JP5451228B2 - Lithium transition metal oxide with layer structure - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention can be used as a positive electrode active material of a lithium battery, and particularly exhibits excellent performance as a positive electrode active material of a battery mounted on an electric vehicle (EV) or a hybrid electric vehicle (HEV). The present invention relates to a lithium transition metal oxide having a layer structure.

  Lithium batteries, especially lithium secondary batteries, have features such as high energy density and long life, so they can be used in home appliances such as video cameras, portable electronic devices such as notebook computers and mobile phones. It is used as a power source, and recently, it is also used for large batteries mounted on electric vehicles (EV) and hybrid electric vehicles (HEV).

  A lithium secondary battery is a secondary battery with a structure in which lithium is melted as ions from the positive electrode during charging, moves to the negative electrode and is stored, and reversely, lithium ions return from the negative electrode to the positive electrode during discharging. It is known to be caused by the potential of the positive electrode active material.

Known positive electrode active materials for lithium secondary batteries include lithium manganese oxide (LiMn ₂ O ₄ ) having a spinel structure, and lithium transition metal oxides such as LiCoO ₂ and LiNiO ₂ having a layer structure. For example, since LiCoO ₂ has a large charge / discharge capacity and excellent diffusibility for occluding and desorbing lithium ions, most of the commercially available lithium secondary batteries are LiCoO having a high voltage of 4 V as a positive electrode active material. ₂ is used. However, since Co is extremely expensive, development of a lithium transition metal oxide having a layer structure that can be used as an alternative material for LiCoO ₂ has been demanded.

Lithium transition metal oxides having a layer structure, such as LiCoO ₂ and LiNiO ₂ , are represented by the general formula LiMeO ₂ (Me: transition metal), and these crystal structures have a space group R-3m (“−” is usually “ 3 ”is attached to the upper part to indicate reversal. The same applies hereinafter). In addition, Li ion, Me ion, and oxide ion occupy the 3a site, 3b site, and 6c site, respectively, and a layer made of Li ions (Li layer), a layer made of Me ions (Me layer), and oxide ions A plurality of O layers are stacked, and a Me layer and a Li layer are alternately stacked via O layers.

As an invention relating to a lithium transition metal oxide (LiM _x O ₂ ) having a layer structure, in Patent Document 1, an alkaline solution is added to a mixed aqueous solution of manganese and nickel to coprecipitate manganese and nickel, and lithium hydroxide is added. In addition, an active material represented by the formula: LiNi _x Mn _1-x O ₂ (where 0.7 ≦ x ≦ 0.95) obtained by firing is disclosed.

Patent Document 2 is composed of oxide crystal particles containing three kinds of transition metals, the crystal structure of the crystal particles is a layered structure, and the arrangement of oxygen atoms constituting the oxide is cubic close-packed packing. , Li [Li _x ( _AP B _Q C _R ) _1-x ] O ₂ (wherein A, B and C are three different transition metal elements, −0.1 ≦ x ≦ 0.3, 0 .. 2 ≦ P ≦ 0.4, 0.2 ≦ Q ≦ 0.4, 0.2 ≦ R ≦ 0.4).

  In Patent Document 3, in order to provide a layered lithium nickel manganese composite oxide powder having a high bulk density, at least a lithium source compound, a nickel source compound, and a manganese source compound, which are pulverized and mixed, are mixed with a nickel atom [Ni]. Layered lithium-nickel-manganese composite oxide powder by drying and firing a slurry containing a molar ratio [Ni / Mn] of 0.7 to 9.0 as a molar ratio [Ni / Mn] to manganese atom [Mn] Then, a method for producing a layered lithium nickel manganese composite oxide powder in which the composite oxide powder is pulverized is disclosed.

Patent Document 4 discloses a lithium transition metal composite oxide having a crystallite size increased by mixing vanadium (V) and / or boron (B), that is, a general formula Li _X M _Y O _Z-δ. (Wherein M represents Co or Ni as a transition metal element, and satisfies the relationship of (X / Y) = 0.98 to 1.02 and (δ / Z) ≦ 0.03). Vanadium ((V + B) / M) = 0.001 to 0.05 (molar ratio) with respect to the transition metal element (M) that includes the transition metal composite oxide and constitutes the lithium transition metal composite oxide. A substance containing V) and / or boron (B), having a primary particle diameter of 1 μm or more, a crystallite diameter of 450 mm or more, and a lattice strain of 0.05% or less is disclosed.

In Patent Document 5, for the purpose of providing a positive active material for a non-aqueous secondary battery comprising primary particles that maintains high bulk density and battery characteristics and does not cause cracking, Co, Ni, and Mn A powdered lithium composite oxide of monodispersed primary particles mainly composed of one element selected from the group and lithium, having an average particle diameter (D50) of 3 to 12 μm and a specific surface area of 0 0.2 to 1.0 m ² / g, the bulk density is 2.1 g / cm ³ or more, and the inflection point of the volume reduction rate by the Cooper plot method does not appear until 3 ton / cm ^2. A positive electrode active material for an aqueous secondary battery has been proposed.

Patent Document 6 discloses a layered rock-salt-type lithium composite material belonging to the R-3m space group as a positive electrode active material that has high thermal stability in a charged state and that has a high initial discharge capacity and good cycle characteristics. an _{oxide, Liα (Ni 1-xy Co} x M y) O β ·· formula (1) (x, y in atomic ratio, 0.05 ≦ x ≦ 0.35,0.01 ≦ y ≦ 0.20, M is one or more elements selected from Mn, Fe, Al, Ga, and Mg, α and β are atomic ratios when the sum of Ni, Co, and element M is 1, and 0 <α < 1.1, 1.9 <β <2.1), the oxygen positional parameter (Zo) is 0.2360 to 0.2420, and the lithium-oxygen distance of formula (2) A positive electrode active material for a lithium secondary battery comprising a lithium composite oxide having (d) of 0.2100 nm to 0.2150 nm is opened. It is shown.

JP-A-8-171910 JP 2003-17052 A Japanese Patent Laid-Open No. 2003-34536 JP 2004-253169 A JP 2004-355824 A JP 2002-124261 A

  Batteries installed in electric vehicles (EV: Electric Vehicle, abbreviated as “EV”) and hybrid vehicles (HEV: Hybrid Electric Vehicle, abbreviated as “HEV”) are used in video cameras, laptop computers, mobile phones, etc. Unlike batteries that are charged / discharged between the limit areas of the charge / discharge depth, such as batteries for consumer products, they are charged / discharged mainly in the central area of the charge / discharge depth (SOC (State Of Charge) = 20 to 80%). The Therefore, in developing a positive electrode active material for a battery mounted on an EV or HEV, it is required to develop a positive electrode active material that can further increase the output of the battery in consideration of such usage conditions. .

  Therefore, an object of the present invention relates to a lithium transition metal oxide having a layer structure, and is excellent in a battery used to repeat charge / discharge mainly in a central region of charge / discharge depth, specifically, SOC of about 20 to 80%. The object is to provide a new lithium transition metal oxide as a positive electrode active material capable of exerting an output.

The present invention has the general formula Li _{1 + x} M _1-xy M′yO _2-δ (where M is an element composed of any one element of Mn, Co and Ni, or a combination of two or more thereof) M ′ is a transition element existing between a Group 3 element and a Group 11 element in the periodic table, or an element composed of a combination of two or more thereof.) The crystal structure belongs to the trigonal crystal of the space group R-3m, the oxygen site occupancy obtained by the Rietveld method is 0.982 <oxygen site occupancy ≦ 0.998, and the 3b site− A lithium transition metal oxide having a layer structure is proposed in which the distance between 6c sites is 1.95 cm <3b sites−6c site distance ≦ 2.05 mm.

When the lithium transition metal oxide of the present invention is mainly used as a positive electrode active material of a lithium secondary battery that is used by repeatedly charging and discharging at a central region of charge / discharge depth, specifically, SOC 20 to 80%, In particular, the output of the battery can be increased. The reason why the output characteristics can be improved is that the transition metal element present between the Group 3 element and the Group 11 element of the periodic table has an electron number equal to or greater than that of Ni, Mn, and Co, which are the main components. Therefore, it can be considered that by replacing some of these, the distance between the 3b site and 6C site can be selectively extended to an appropriate range, thereby increasing the output of the battery. it can.
Therefore, the lithium transition metal oxide having the layer structure of the present invention is particularly excellent for use as a positive electrode active material of a battery mounted on an electric vehicle (EV) or a hybrid electric vehicle (HEV).

It is the figure which showed the structure of the cell for electrochemical evaluation produced for the battery evaluation of the sample obtained by the Example and the comparative example. It is the figure which showed the structure of the 2032 type | mold coin type | mold battery produced in order to evaluate the battery characteristic of the sample obtained by the test example and the comparative test example. 2 is a chart of a volume-based particle size distribution of a lithium transition metal oxide powder (sample) obtained in Test Example 1. FIG. 4 is a SEM photograph of the lithium transition metal oxide powder (sample) obtained in Test Example 1. 6 is a chart of a volume-based particle size distribution of a lithium transition metal oxide powder (sample) obtained in Comparative Test Example 2. 4 is a SEM photograph of lithium transition metal oxide powder (sample) obtained in Comparative Test Example 2.

  Hereinafter, although embodiment of this invention is described, this invention is not limited to the following embodiment.

(composition)
The lithium transition metal oxide of the present embodiment (hereinafter referred to as “the present Li transition metal oxide”) is a lithium transition metal oxide represented by the general formula (1) Li _{1 + x} M _1-xy M′yO _2−δ It is a powder mainly composed of an object.

In addition, unless otherwise specified, “with a main component” includes the meaning that allows other components to be included as long as the function of the main component is not hindered. Although the content ratio of the main component is not specified, it includes a case where it occupies at least 50% by mass or more, particularly 70% by mass or more, especially 90% by mass or more, especially 95% by mass or more (including 100%). For example, the present Li-transition metal oxide may contain 1.0 wt% or less of SO ₄ as impurities and 0.1 wt% or less of other elements. This is because it is considered that the amount of this amount hardly affects the characteristics of the present Li transition metal oxide.

  In the general formula (1), the “M element” may be any element of any one of Mn, Co, and Ni or a combination of two or more thereof. Among these, it is preferable that all three elements of Mn, Co, and Ni are included.

The “M ′ element” is a transition element present between the Group 3 element and the Group 11 element of the periodic table, or an element composed of a combination of two or more thereof.
Examples of transition elements present between Group 3 elements to Group 11 elements of the periodic table include scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), lanthanum (La), Ce (cerium), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), luteti (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), and the like. .
Among these, from the viewpoint of improving output, an element composed of Ti, Zr, Nb, Mo, W, or a combination of two or more of these is preferable.

When the general formula (1) is expressed by Li _{1 + x} (Mn _α Co _β Ni _γ ) _1-xy M ′ _y O _2−δ , the molar ratio (α) of Mn is 0.10 ≦ α ≦ 0. .40, particularly 0.18 ≦ α ≦ 0.35, and more preferably 0.18 ≦ α ≦ 0.31.
The molar ratio (β) of Co is preferably 0.10 ≦ β ≦ 0.40, particularly 0.18 ≦ β ≦ 0.35, and particularly 0.18 ≦ β ≦ 0.31. Even more preferred.
The molar ratio (γ) of Ni is preferably 0.30 ≦ γ ≦ 0.75, particularly 0.31 ≦ γ ≦ 0.59, and particularly 0.36 ≦ γ ≦ 0.59. Even more preferred.

  In the general formula (1), “1 + x” indicating the molar ratio of Li is preferably 1.00 ≦ 1 + x ≦ 1.08, and 1.01 ≦ 1 + x ≦ 1.07. And more preferably 1.03 ≦ 1 + x ≦ 1.07, and more preferably 1.05 ≦ 1 + x ≦ 1.07.

“Y” indicating the molar ratio of the M ′ element is preferably 0.001 ≦ y ≦ 0.03, particularly preferably 0.001 ≦ y ≦ 0.01, and particularly 0.001 ≦ y. More preferably, y ≦ 0.005.
By increasing the molar ratio of the M ′ element, it is possible to further increase the output by increasing the distance between the 3b site and the 6c site. However, the discharge capacity of the battery decreases as the substitution amount of the M ′ element increases. Therefore, the substitution amount of the M ′ element is preferably y ≦ 0.03, particularly preferably y ≦ 0.01, and particularly preferably y ≦ 0.005.
The atomic ratio of oxygen may have some nonstoichiometry (for example, represented by 2-δ), or a part of oxygen may be substituted with fluorine.

(Crystal structure)
The crystal structure of the present Li transition metal oxide belongs to the trigonal space group R-3m, the Li ion occupies the 3a site, the M and M 'ions occupy the 3b site, and the oxide ion occupies the 6c site. To do.
Here, “3a site”, “3b site” and “6c site” mean Wyckoff positions indicating atomic positions.

In the present Li transition metal oxide, the distance between the 3b site and the 6c site (referred to as “3b-6c distance”) is 1.95Å <3b-6c distance ≦ 2.05Å mainly from the viewpoint of increasing the output. It is important that 1.96? ≤3b-6c distance? 2.02 ?, particularly 1.97? ≤3b-6c distance≤1.99 ?.
The charge / discharge reaction in the positive electrode active material proceeds in the following steps, and it is considered that the output can be improved by increasing the reaction rate in each stage.
1) The movement of Li ⁺ ions proceeds in a redox reaction in the solid phase of the positive electrode active material, that is, in pairs with electron transfer between the active material host lattice and the current collector. Since this oxidation-reduction reaction propagates throughout the active material while maintaining electrical neutrality, electrons and Li ⁺ ions move through the host lattice.
2) When ions and electrons enter and exit, the valence of atoms constituting the host material of the active material changes, and the rearrangement of the lattice proceeds accordingly. For this reason, the host material of the active material is formed as Li ⁺ ions come in and out by extending the distance between the 3b site and 6c site to an appropriate range, that is, by giving the ion bonding property more than the covalent bonding property. It can be presumed that the valence change of the atoms proceeding rapidly proceeds and the output characteristics can be improved.
The distance between the 3b site and the 6c site can be extended by substitution of the M ′ element, but can also be extended by raising the firing temperature.

(Oxygen seat occupancy rate)
It is important that the oxygen site occupancy (referred to as “Occ”) of the Li transition metal oxide obtained by the Rietveld method is 0.982 <Occ ≦ 0.998, and 0.983 ≦ Oc ≦ 0.998. It is preferable that there is particularly preferable, and it is more preferable that 0.989 ≦ Occ ≦ 0.998.
By controlling the distance between the 3b site and 6c site to a predetermined range and controlling the oxygen seat occupancy ratio to 0.982 <Occ ≦ 0.998, the influence on the electron density can be preferably adjusted. It is considered that the crystal structure can be further stabilized.
The control of the oxygen seat occupancy can be adjusted by selecting the firing atmosphere. For example, if firing in an atmosphere having an oxygen concentration of about 21% or less, oxygen deficiency is likely to occur compared to firing in an oxygen atmosphere (oxygen of about 100%), so the oxygen seat occupancy is lower than 1.0. Can be adjusted as follows.

(Crystallite diameter / D50)
In the present Li transition metal oxide, the average particle diameter (D50) obtained by the laser diffraction scattering particle size distribution measurement method is compared with the crystallite diameter obtained by the measurement method by the Rietveld method (for details, refer to the measurement conditions in the examples). The ratio (crystallite diameter / D50) is preferably 0.03 to 0.13, more preferably 0.03 to 0.12, and particularly preferably 0.03 to 0.11.
When the ratio of crystallite diameter / D50 is 0.03 to 0.13, it is used as a positive electrode active material for a battery that is used by repeatedly charging and discharging in the central region (for example, SOC 20 to 80%) of the charging and discharging depth. In particular, excellent life characteristics (also referred to as cycle characteristics) and output characteristics (characteristics evaluated in the low temperature capacity test 3 and 6 in the examples) can be exhibited.

Here, “crystallite” means the largest group that can be regarded as a single crystal, and can be obtained by performing XRD measurement and performing Rietveld analysis.
In the present invention, the smallest unit particle composed of a plurality of crystallites and surrounded by a grain boundary when observed by SEM (for example, 3000 times) is referred to as “primary particle”. Accordingly, the primary particles include single crystals and polycrystals.
Further, in the present invention, a plurality of primary particles aggregate together so as to share a part of each outer periphery (grain boundary) and are isolated from other particles in the present invention are referred to as “secondary particles” or “aggregated particles”. .
Incidentally, the laser diffraction / scattering particle size distribution measurement method is a measurement method in which agglomerated powder particles are regarded as one particle (aggregated particle) to calculate the particle size, and the average particle size (D50) is 50% volume cumulative particle. The diameter, that is, the diameter of 50% cumulative from the finer one of the cumulative percentage notation of the measured particle size converted into volume in the chart of the volume standard particle size distribution.

(Crystallite diameter)
The crystallite diameter of the present Li transition metal oxide, that is, the crystallite diameter determined by the measurement method by the Rietveld method (details are described in the Examples section) is preferably 0.01 μm to 0.50 μm. It is preferably 0.05 μm to 0.40 μm, more preferably 0.05 μm to 0.30 μm, and particularly preferably 0.07 μm to 0.27 μm.
By relatively reducing the crystallite diameter of the present Li transition metal oxide, the output tends to be increased.
The crystallite diameter can be adjusted by the transition metal composition ratio (for example, composition ratio such as Mn: Co: Ni ratio, Li: Mn ratio, etc.), raw material particle size, firing conditions, and the like. For example, the crystallite diameter can be reduced by lowering the firing temperature.

(Average particle size of primary particles)
The average particle size of the primary particles of the present Li transition metal oxide is preferably 0.5 μm to 5.0 μm, particularly 0.7 μm to 4.0 μm, especially 1.0 μm to 3.0 μm. Is preferred.
The average particle diameter of the primary particles was observed using a scanning electron microscope (HITACHI S-3500N) at an acceleration voltage of 20 kV and a magnification of 3000 times, and the primary particle image of the electron micrograph was analyzed by image analysis software (analysis made by OLYMPUS). FIVE).

(D50)
The average particle diameter (D50) obtained by the laser diffraction scattering type particle size distribution measuring method of the present Li transition metal oxide is preferably 1.0 μm ≦ D50 ≦ 4.0 μm, and particularly 1.5 μm ≦ D50 ≦ 3. It is preferably 0 μm, particularly 2.0 μm ≦ D50 <3.0 μm.

(D90)
The 90% cumulative diameter (D90) obtained by the laser diffraction scattering type particle size distribution measurement method of the present Li transition metal oxide is preferably 2.0 μm to 10.0 μm, particularly 2.5 μm to 8.0 μm, In particular, the thickness is preferably 3.0 μm to 6.0 μm.
By adjusting the 90% integrated diameter (D90) to 2.0 μm to 10.0 μm, that is, adjusting the particle size of the coarse powder to the range of 2.0 μm to 10.0 μm, The present coarse foreign particles, particularly metallic coarse foreign particles such as iron, nickel, chromium, and zinc can be removed, and the occurrence of minute short circuits can be suppressed. Therefore, when a battery is formed using the present Li transition metal oxide as the positive electrode active material, the coarse foreign particles can be prevented from eluting from the positive electrode, segregating and depositing on the negative electrode, breaking through the separator and causing an internal short circuit.
It has been confirmed that the presence of impurities inside the positive electrode active material crystal does not affect the occurrence of a micro short circuit. By adjusting D90 to 2.0 μm to 10.0 μm, the positive electrode active material crystal The idea of removing coarse foreign particles present on the outside of the metal to prevent the occurrence of micro short circuits is completely different from the idea of reducing the so-called total iron content.

(Particle size distribution)
Further, the Li transition metal oxide is preferably one in which the particle size distribution curve (histogram curve) is a mountain when a chart of the volume reference particle size distribution is obtained using a laser diffraction scattering type particle size distribution measuring apparatus.

(Iron content)
The amount of iron of the present Li transition metal oxide, that is, the amount of iron per weight of the present Li transition metal oxide is preferably 0 ppb <the amount of iron <75 ppb, particularly preferably 0 ppb <the amount of iron <35 ppb.

(Production method)
Next, the manufacturing method of this Li transition metal oxide powder is demonstrated.

  The present Li transition metal oxide powder is prepared by mixing raw materials, for example, a lithium salt compound, an M element compound, and an M ′ element compound, and pulverizing with a wet pulverizer or the like until the average particle size (D50) is 2 μm or less. Then, it is granulated and dried using a thermal spray dryer or the like, fired, classified as necessary, and an average particle diameter (D50) and a crystallite diameter are determined using a collision type pulverizer equipped with a classification mechanism. It can be obtained by grinding so that the ratio falls within a predetermined range, further heat-treating as necessary, and further classifying as necessary. However, the manufacturing method of the lithium transition metal oxide of the present invention is not limited to such a manufacturing method. For example, a granulated powder for firing may be produced by a so-called coprecipitation method.

Examples of the lithium salt compound include lithium hydroxide (LiOH), lithium carbonate (Li ₂ CO ₃ ), lithium nitrate (LiNO ₃ ), LiOH · H ₂ O, lithium oxide (Li ₂ O), other fatty acid lithium and lithium halogen. And the like. Of these, lithium hydroxide salts, carbonates and nitrates are preferred.

Examples of the M element compound include a manganese salt compound, a nickel salt compound, and a cobalt salt compound.
The kind of manganese salt compound is not particularly limited. For example, manganese carbonate, manganese nitrate, manganese chloride, manganese dioxide and the like can be used, and among these, manganese carbonate and manganese dioxide are preferable. Among these, electrolytic manganese dioxide obtained by an electrolytic method is particularly preferable.
The kind of the nickel salt compound is not particularly limited, and for example, nickel carbonate, nickel nitrate, nickel chloride, nickel oxyhydroxide, nickel hydroxide, nickel oxide, etc. can be used, among which nickel carbonate, nickel hydroxide, nickel oxide are used. preferable.
The type of cobalt salt compound is not particularly limited, and for example, basic cobalt carbonate, cobalt nitrate, cobalt chloride, cobalt oxyhydroxide, cobalt hydroxide, cobalt oxide and the like can be used. Cobalt, cobalt oxide, and cobalt oxyhydroxide are preferred.

  Examples of the M ′ element compound include oxides containing carbonate and hydroxide of M ′ element.

The mixing of the raw materials is preferably performed by adding a liquid medium such as water or a dispersant and wet mixing to form a slurry, and the obtained slurry is preferably pulverized by a wet pulverizer. However, dry pulverization may be performed.
And it is preferable to grind | pulverize so that an average particle diameter (D50) may be 2 micrometers or less, especially an average particle diameter (D50) 0.5 micrometer-1.0 micrometer.

  The granulation method may be wet or dry as long as the various raw materials pulverized in the previous step are dispersed in the granulated particles without being separated, and the extrusion granulation method, rolling granulation method, fluidized granulation method, A mixed granulation method, a spray drying granulation method, a pressure molding granulation method, or a flake granulation method using a roll or the like may be used. However, when wet granulation is performed, it is necessary to sufficiently dry before firing. As a drying method, it may be dried by a known drying method such as a spray heat drying method, a hot air drying method, a vacuum drying method, a freeze drying method, etc. Among them, the spray heat drying method is preferable. The spray heat drying method is preferably performed using a heat spray dryer (spray dryer).

Firing is performed at a temperature of 850 to 1100 ° C. (in the calcined product in the calcining furnace) in an air atmosphere, an atmosphere in which the oxygen partial pressure is adjusted, a carbon dioxide gas atmosphere, or other atmosphere in a calcining furnace. It is preferably fired so as to hold for 0.5 to 30 hours at a temperature when a thermocouple is brought into contact. At this time, it is preferable to select firing conditions in which the transition metal is dissolved at the atomic level and exhibits a single phase.
The kind of baking furnace is not specifically limited. For example, it can be fired using a rotary kiln, a stationary furnace, or other firing furnace.

  The classification after firing has technical significance of adjusting the particle size distribution of the agglomerated powder and removing foreign matter, and it is preferable to classify so that the average particle diameter (D50) is 10 μm to 50 μm.

The pulverization after classification is performed by using a collision type pulverizer with a classification mechanism, for example, a counter jet mill with a classification rotor so that the ratio of the average particle diameter (D50) and the crystallite diameter falls within a predetermined range. Is preferred.
More preferably, the powder is pulverized so that the particle size distribution curve (histogram curve) of the powder becomes a mountain. That is, the particle size distribution of the obtained powder is measured by a laser diffraction / scattering particle size distribution measurement method, and the obtained volume-based particle size frequency distribution curve (histogram curve) shows a particle size distribution curve having one peak. It is preferable to grind as follows. At this time, the “peak” in the volume-based particle size distribution curve (histogram curve) means that the slope of the frequency distribution curve indicating the volume-based particle size frequency distribution (histogram) is positive when viewed from the smaller particle size to the larger particle size. The point that changes to negative. Note that even if a peak having a peak top with a frequency of less than 0.5% in the volume-based particle size distribution is present, its influence can be ignored. Therefore, such a peak is included in the peak targeted by the present invention. Make it not exist.
The powder particles obtained by pulverization with a collision type pulverizer with a classification mechanism are usually non-spherical.

  The heat treatment is preferably performed for 0.5 to 20 hours in an atmosphere of 300 ° C. to 700 ° C., preferably 600 ° C. to 700 ° C. in an air atmosphere. At this time, if the temperature is lower than 300 ° C., the effect of the heat treatment is difficult to obtain and the fine powder may remain without being sintered. On the other hand, if the heat treatment is performed at a temperature higher than 700 ° C., sintering starts and the present invention is aimed. It becomes impossible to obtain the powder characteristics.

  The classification after the heat treatment has a technical significance of adjusting the particle size distribution of the agglomerated powder and removing the foreign matter, and it is preferable to classify in the range of an average particle diameter (D50) of 1.0 μm to 4.0 μm.

(Characteristics / Applications)
The present Li transition metal oxide powder can be effectively used as a positive electrode active material of a lithium battery after being crushed and classified as necessary.
For example, this Li transition metal oxide powder, a conductive material made of carbon black, etc., and a binder made of Teflon (Teflon is a registered trademark of DUPONT, USA) binder, etc. are mixed to form a positive electrode mixture. Can be manufactured. Such a positive electrode mixture is used for the positive electrode, for example, a material that can store and desorb lithium such as lithium or carbon is used for the negative electrode, and lithium such as lithium hexafluorophosphate (LiPF ₆ ) is used for the non-aqueous electrolyte. A lithium secondary battery can be formed by using a salt dissolved in a mixed solvent such as ethylene carbonate-dimethyl carbonate. However, the present invention is not limited to the battery having such a configuration.

A lithium battery equipped with the present Li transition metal oxide powder as a positive electrode active material has excellent life characteristics (cycle characteristics) when it is repeatedly charged and discharged in the central region of the charge / discharge depth (for example, SOC 20-80%). In particular, it exhibits excellent output characteristics, and is particularly excellent in the use of a positive electrode active material of a lithium battery used as a power source for driving a motor mounted on an electric vehicle (EV) or a hybrid electric vehicle (HEV). Yes.
The “hybrid vehicle” is a vehicle that uses two power sources, that is, an electric motor and an internal combustion engine, and includes a plug-in hybrid vehicle.
The term “lithium battery” is intended to encompass all batteries containing lithium or lithium ions in the battery, such as lithium primary batteries, lithium secondary batteries, lithium ion secondary batteries, and lithium polymer batteries.

(Explanation of terms)
In the present specification, when expressed as “X to Y” (X and Y are arbitrary numbers), unless otherwise specified, “preferably greater than X” and “preferably Y” together with the meaning of “X to Y”. It means “smaller”. Further, X and Y at that time are numerical values considering rounding.
Further, when expressed as “X or more” or “Y or less” (X and Y are arbitrary numbers), it means “preferably larger than X” or “preferably smaller than Y” unless otherwise specified. To do. Further, X and Y at that time are numerical values considering rounding.

  Next, the present invention will be further described based on examples and comparative examples, but the present invention is not limited to the examples shown below.

<Measurement of crystallite diameter, oxygen site occupancy, and site-to-site distance by Rietveld method>
The Rietveld method is a method of refining the crystal structure parameters from the diffraction intensity obtained by powder X-ray diffraction or the like. This method assumes a crystal structure model, and refines various parameters of the crystal structure so that the X-ray diffraction pattern derived from the structure and the measured X-ray diffraction pattern match as much as possible.

  In the measurement of the X-ray diffraction pattern of this example, an X-ray diffractometer using Cu-Kα rays (D8 ADVANCE manufactured by Bruker AXS Co., Ltd.) was used, and analysis was performed using a FundamentalParameter. . Using the X-ray diffraction pattern obtained from the range of diffraction angle 2θ = 15 to 120 °, analysis software Topas Version 3 was used.

The crystal structure is attributed to the space group R-3m trigonal (Trigonal), the 3a site is Li, the 3b site is Mn, Co, Ni, the substitution element M ′ and the excess Li content x, and the 6c site is Assuming that it is occupied by O, the oxygen occupancy (Occ.), The crystallite diameter (Gauss), and the distance between 3b-6c sites were determined. It is assumed that the isotropic temperature factor (Beq.) Is 1, and refinement is performed to Rwp <5.0 and GOF <1.3.
As a refinement procedure, Beq = 1 is fixed, and each variable does not change in a state where the z coordinate of oxygen, the seat occupancy, the crystallite diameter (Gauss), and the bond distance between each site are variables. Repeated until.

The above Rwp and GOF are values obtained by the following formulas (see: “Practice of powder X-ray analysis”, edited by Japan Analytical Chemistry X-ray Analysis Research Roundtable, published by Asakura Shoten. February 2002) 10 days, Table 6.2 of p107).
Rwp = [Σ _i wi {yi-fi (x) ² } / Σ _i wiyi ² ] ^1/2
Re = [(NP) / Σiwiyi ² ] ^1/2
GOF = Rwp / Re
However, wi is a statistical weight, yi is an observation intensity, fi (x) is a theoretical diffraction intensity, N is the total number of data points, and P is the number of parameters to be refined.

Other equipment specifications and conditions used for other measurement and Rietveld method analysis are as follows. In the analysis, it was assumed that the lithium transition metal oxide belonging to the trigonal crystal belongs to the hexagonal crystal.
Sample disp (mm): Refine
Generate Bond-lengths / errors: Refine
Detector: PSD
Detector Type: VANTEC-1
High Voltage: 5616V
Discr. Lower Level: 0.45V
Discr. Window Width: 0.15V
Grid Lower Level: 0.075V
Grid Window Width: 0.524V
Flood Field Correction: Disabled
Primary radius: 250mm
Secondary radius: 250mm
Receiving slit width: 0.1436626mm
Divergence angle: 0.3 °
Filament Length: 12mm
Sample Length: 25mm
Receiving Slit Length: 12mm
Primary Sollers: 2.623 °
Secondary Sollers: 2.623 °
Lorentzian, 1 / Cos: 0.01630098Th

Det. 1 voltage: 760.00V
Det. 1 gain: 80.000000
Det. 1 discr. 1 LL: 0.6900000
Det. 1 discr. 1 WW: 1.078000
Scan Mode: Continuous Scan
Scan Type: Locked Coupled
Spinner Speed: 15rpm
Divergence Slit: 0.300 °
Start: 15.000000
Time per step: 1s
Increment: 0.01460
#Steps: 7152
Generator voltage: 35kV
Generator current: 40 mA

As for the valence of each element used for refinement, the values of Li (1+), Ni (2+), Co (3+), Mn (4+) are used for convenience. The values shown in Table 1 were used.
For transition elements other than these, the following valences may be used for convenience.
Sc (3+), V (4+), Cr (4+), Mn (4+), Fe (4+), Cu (3+), Zn (2+), Y (3+), Tc ( 4+), Ru (4+), Rh (5+), Pd (3+), Ag (3+), La (3+), Ce (4+), Pr (4+), Nd (3+ ), Pm (3+), Sm (3+), Eu (3+), Gd (3+), Tb (4+), Dy (3+), Ho (3+), Er (3+), Tm (3+), Yb (3+), Lu (3+), Hf (4+), Ta (4+), Re (4+), Os (4+), Ir (4+), Pt ( 4+), Au (3+)

<Measurement of average particle diameter (D50), 90% integrated diameter (D90)>
The particle size distribution of the samples (powder) obtained in Examples and Comparative Examples was measured as follows.

Using a sample circulator for laser diffraction particle size distribution analyzer (“Microtorac ASVR” manufactured by Nikkiso Co., Ltd.), a sample (powder) was put into water and irradiated with ultrasonic waves of 40 watts at a flow rate of 40 mL / sec for 360 seconds. Thereafter, the particle size distribution was measured using a laser diffraction particle size distribution measuring instrument “HRA (X100)” manufactured by Nikkiso Co., Ltd., and D50 and D90 were determined from the obtained volume-based particle size distribution chart.
The water-soluble solvent used in the measurement was water that passed through a 60 μm filter, the solvent refractive index was 1.33, the particle permeability was reflected, the measurement range was 0.122 to 704.0 μm, and the measurement time was The average value measured twice for 30 seconds was used as the measured value.

<Measurement and evaluation of iron content>
The sample (powder) was slurried and a magnet coated with tetrafluoroethylene was put into the slurry to attach the magnetic deposit to the magnet. Then, JIS G 1258: 1999 was referred to, and the magnet attached to the magnet The kimono was acid-dissolved to determine the amount of iron. Next, this will be described in detail.
In addition, since the magnetized material adhering to the magnet is a very small amount, it is necessary to immerse the magnet together in an acidic solution to dissolve the magnetized material in an acid solution. Then, the magnet (100mT-150mT, cylindrical shape, diameter 2cm, length 5cm, surface area 37.7cm < ² >) covered with tetrafluoroethylene was used for the magnet, and the intensity | strength of each magnet was measured before the measurement. The strength of the magnet was measured using a TESLA METER model TM-601 manufactured by KANETEC.

In a 1000 cc polypropylene pot, 100 g of lithium transition metal oxide powder (sample) and 500 cc of ion exchange water are put into a slurry, and one magnet (100 mT to 150 mT) is put into this slurry, and a ball mill is added. The sample was placed on a rotating gantry and rotated at 60 rpm for 30 minutes.
Next, the magnet is taken out, placed in a 300 mL tall beaker, immersed in ion-exchanged water, and 3 by a two-frequency method (simultaneous oscillation of 28 kHz / 38 kHz) using an ultrasonic cleaner (model US-205, manufactured by SND Corporation). The ion-exchanged water in which the magnet was immersed was exchanged, and the fine powder magnetically attached to the magnet was removed by repeating the exchange of ion-exchanged water and washing with ultrasonic waves 8 times in this way.

  Next, the magnet is taken out and placed in a 100 mL graduated cylinder and immersed in aqua regia (a liquid in which concentrated hydrochloric acid and concentrated nitric acid are mixed at a volume ratio of 3: 1) so that the magnet is completely submerged. The magnetized material was dissolved by heating at 30 ° C. for 30 minutes. Next, the magnet is taken out from the aqua regia, the aqua regia in which the magnetic deposits are dissolved is diluted with ion-exchanged water, the diluted aqua regia is analyzed by ICP, the amount of Fe is quantified, and the amount of iron per sample weight is calculated. did.

Based on the amount of iron per sample weight obtained, lithium transition metal oxide powders were evaluated and selected according to the following criteria.
0 ppb <iron amount <35 ppb: ◎ (preferably applicable)
35 ppb ≤ iron content <75 ppb: ○ (adoptable)
75 ppb ≤ iron amount: × (not applicable)

<Battery evaluation>
Considering the charge / discharge depth (SOC = 20 to 80%) in which the battery is mainly used in EV and HEV, the following battery evaluation was performed.

In 8.00 g of lithium transition metal oxide powder (sample) as a positive electrode active material, 1.00 g of acetylene black (manufactured by Denki Kagaku Kogyo) as a conductive material, and N-methyl-2-pyrrolidone (NMP) 8.30 g of a solution containing 12 wt% of polyvinylidene fluoride (PVDF, manufactured by Kishida Chemical Co., Ltd.) and 5 mL of N-methyl-2-pyrrolidone (NMP) are mixed, and a planetary stirring and deaerator (Mazerustar KK manufactured by Kurabo Industries Co., Ltd.) -50S) to obtain a paste-like positive electrode mixture.
This paste-like positive electrode mixture was applied onto an aluminum foil as a current collector using an applicator with a clearance adjusted to 350 μm, vacuum-dried at 120 ° C. overnight, punched out with a 14 mmφ punch, and 4 t / cm ^2. A positive electrode plate was obtained by press-consolidating at a pressure of

When producing the battery, immediately before producing the battery, this positive electrode was vacuum-dried at 120 ° C. for 120 minutes to remove the adhering moisture and incorporated in the battery.
Further, the weight of an aluminum foil having a diameter of 14 mmφ was obtained in advance, the weight of the aluminum foil was subtracted from the weight of the positive electrode plate, and the weight of the applied positive electrode mixture was obtained. Further, when the content of the positive electrode active material was determined from the mixing ratio of the positive electrode active material, acetylene black and PVDF, the positive electrode active material in one positive electrode plate was about 40 mg.

The electrochemical evaluation cell “TOMCELL (registered trademark)” in FIG. 1 was produced using metal Li having a diameter of 20 mm and a thickness of 1.0 mm as the negative electrode.
That is, as shown in FIG. 1, the positive electrode plate 3 is disposed in the center of the inner side of the lower body 1 made of organic electrolyte resistant stainless steel. On the upper surface of the positive electrode plate 3, a polypropylene separator (“Celguard 2400”) 4 impregnated with an electrolytic solution is disposed, and the separator 4 is fixed by a Teflon spacer 5 (“Teflon” is a registered trademark of DUPONT USA). . Further, on the upper surface of the separator 4, the negative electrode 6 is disposed below, the spacer 7 also serving as a negative electrode terminal is disposed, the upper body 2 is placed on the upper surface, the screws are tightened, the battery is sealed, and the electrochemical An evaluation cell was produced.
As the electrolytic solution, a mixture of EC and DMC in a volume ratio of 3: 7 was used as a solvent, and a solution obtained by dissolving 1 mol / L of LiPF ₆ as a solute was used.

  In the cycle test 1, charge and discharge were repeated 30 times at 45 ° C. in the range of the electrode potential from 3.0 V to 4.3 V. The ratio of the discharge capacity after 30 cycles to the discharge capacity at the third cycle was defined as a cycle retention rate, and the relative value when the cycle retention rate of Example 1 was set to 100 was evaluated. Charging / discharging was performed at a constant current value corresponding to the 0.2C rate. The C rate represents a current value for charging / discharging the entire capacity of the battery over one hour as a 1C rate, and how many times the current value is charged / discharged. The 0.2C rate means charging / discharging at a current value 0.2 times the 1C rate, and indicates a current value for charging / discharging the entire battery capacity in 5 hours.

  In cycle test 2, charging and discharging were repeated 30 times at 55 ° C. in the range of SOC: 20 to 80%. The ratio of the discharge capacity at the 30th cycle to the discharge capacity at the 3rd cycle was defined as a cycle retention rate, and the relative value was evaluated when the cycle retention rate of Example 1 was 100. Here, SOC means the depth of charge, and SOC 80% means charging at a current value of 0.2 C from the open circuit voltage to 4.1 V at 25 ° C. and then charging at a constant voltage of 4.3 V. It means a state of charge of 80% of the capacity.

  In the low-temperature capacity confirmation test 3, the charge / discharge cycle of charging and discharging in the range of 3.0 to 4.3 V at a constant current of 1 C rate at 0 ° C. was repeated, and the discharge capacity of the third cycle was measured. Evaluation was made with a relative value when the discharge capacity at the third cycle of 1 was 100.

Example 1
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And titanium oxide having an average particle diameter (D50) of 2.1 μm in a molar ratio of Li: Mn: Co: Ni: Ti = 1.07: 0.30: 0.30: 0.30: 0.03 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%.
To the obtained slurry (raw material powder 20 kg), polycarboxylic acid ammonium salt (SN Dispersant 5468 manufactured by San Nopco Co., Ltd.) as a dispersant was added 6 wt% of the slurry solid content, and pulverized at 1300 rpm for 29 minutes with a wet pulverizer. The average particle size (D50) was 0.7 μm.
The obtained pulverized slurry was granulated and dried using a thermal spray dryer (spray dryer, OC-16 manufactured by Okawahara Chemical Co., Ltd.). At this time, a rotating disk was used for spraying, and granulation drying was performed by adjusting the temperature so that the rotation speed was 21,000 rpm, the slurry supply amount was 24 kg / hr, and the outlet temperature of the drying tower was 100 ° C.

  The obtained granulated powder was baked at 975 ° C. for 20 hours in the air using a stationary electric furnace. The fired powder obtained by firing is classified with a sieve having an opening of 75 μm, and the powder under the sieve is rotated by a classification rotor using a collision type pulverizer with a classification mechanism (Counterjet mill “100AFG / 50ATP” manufactured by Hosokawa Micron). Number: 14900 rpm, pulverization air pressure: 0.6 MPa, pulverization nozzle φ: 2.5 × 3 used, powder supply amount: 4.5 kg / h, pulverization, lithium transition metal oxide powder (sample )

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Example 2)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And zirconia oxide having an average particle diameter (D50) of 13 μm in a molar ratio of Li: Mn: Co: Ni: Zr = 1.07: 0.30: 0.30: 0.30: 0.03 Then, water was added and mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%. Thereafter, the same treatment as in Example 1 was performed to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Example 3)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And niobium oxide having an average particle size (D50) of 2.9 μm in a molar ratio of Li: Mn: Co: Ni: Nb = 1.07: 0.30: 0.30: 0.30: 0.03 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%. Thereafter, the same treatment as in Example 1 was performed to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

Example 4
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And molybdenum oxide having an average particle diameter (D50) of 1.9 μm in a molar ratio of Li: Mn: Co: Ni: Mo = 1.07: 0.30: 0.30: 0.30: 0.005 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%. Thereafter, the same treatment as in Example 1 was performed to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Example 5)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And tungsten oxide having an average particle diameter (D50) of 2.5 μm in a molar ratio of Li: Mn: Co: Ni: W = 1.07: 0.30: 0.30: 0.30: 0.005 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%. Thereafter, the same treatment as in Example 1 was performed to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Example 6)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And titanium oxide having an average particle diameter (D50) of 2.1 μm in a molar ratio of Li: Mn: Co: Ni: Ti = 1.07: 0.18: 0.17: 0.55: 0.03 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%.
Thereafter, a treatment was performed in the same manner as in Example 1 except that the firing conditions were changed to 900 ° C. for 20 hours to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Example 7)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And titanium oxide having an average particle diameter (D50) of 2.1 μm in a molar ratio of Li: Mn: Co: Ni: Ti = 1.06: 0.30: 0.30: 0.30: 0.03 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%.
Thereafter, the same treatment as in Example 1 was performed to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Example 8)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And titanium oxide having an average particle diameter (D50) of 2.1 μm in a molar ratio of Li: Mn: Co: Ni: Ti = 1.08: 0.30: 0.30: 0.30: 0.03 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%.
Thereafter, the same treatment as in Example 1 was performed to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

Example 9
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And titanium oxide having an average particle diameter (D50) of 2.1 μm in a molar ratio of Li: Mn: Co: Ni: Ti = 1.08: 0.17: 0.18: 0.54: 0.03 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%.
Thereafter, a treatment was performed in the same manner as in Example 1 except that the firing conditions were changed to 900 ° C. for 20 hours to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Example 10)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm And titanium oxide having an average particle diameter (D50) of 2.1 μm in a molar ratio of Li: Mn: Co: Ni: Ti = 1.06: 0.19: 0.19: 0.53: 0.03 The slurry was weighed, added with water, mixed and stirred to prepare a slurry having a solid content concentration of 50 wt%.
Thereafter, a treatment was performed in the same manner as in Example 1 except that the firing conditions were changed to 900 ° C. for 20 hours to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and battery characteristics were evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Comparative Example 1)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, cobalt oxyhydroxide with an average particle size (D50) of 14 μm, and nickel hydroxide with an average particle size (D50) of 25 μm In a molar ratio of Li: Mn: Co: Ni = 1.07: 0.31: 0.31: 0.31, added water, mixed and stirred to a solid content concentration of 50 wt%. A slurry was prepared. Thereafter, the same treatment as in Example 1 was performed to obtain a lithium transition metal oxide powder (sample).

The obtained lithium transition metal oxide powder (sample) was measured for crystallite diameter, oxygen site occupancy, intersite distance, and iron content, and thermal stability was evaluated.
Further, with respect to the obtained lithium transition metal oxide powder (sample), a chart of volume-based particle size distribution using a laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. Was found to have a single particle size distribution. That is, the differential inflection point was one point.
Each element concentration shown in Table 1 is a value calculated from an analysis value by ICP.

(Discussion)
From the results in Table 1, as in Example 1-10, in the lithium transition metal oxide as the positive electrode active material, Mn, Co and part of Ni, which are main component elements, are Ti, Zr, Nb, Mo, It was confirmed that the output of the battery can be increased by substituting with any of W to make the oxygen site occupancy constant within a certain range and the distance between the 3b site and 6c site within a certain range.

From the results of Example 1-10 and other experimental results, from the viewpoint of further stabilizing the crystal structure and increasing the output, the oxygen site occupancy (Occ) is 0.982 <Occ ≦ 0.998. It is important that 0.983 ≦ Oc ≦ 0.998, particularly 0.989 ≦ Occ ≦ 0.998.
In addition, with respect to the distance between the 3b site and the 6c site, it is important that 1.95 mm <3b site−6c site distance ≦ 2.05 mm mainly from the viewpoint of increasing the output, and 1.96 mm ≦ 3b site−. It is preferable that the distance between 6c sites ≦ 2.02 mm, and it can be considered that the distance between 1.97 mm ≦ 3b sites−6c sites ≦ 1.99 mm is even more preferable.

By setting the distance between the 3b site and the 6c site within an appropriate range, the covalent bond is strengthened, so that the ion bondability of the 3a site and the 6c site is strengthened, and Li ions enter and exit smoothly by oxidation and reduction. It can be inferred that it is possible to improve the above.
Considering the above points, the transition metal element present between the Group 3 element and the Group 11 element in the periodic table has an electron number equal to or greater than that of Ni, Mn, and Co, which are the main components. Therefore, like the elements such as Ti, Zr, Nb, Mo, and W shown in Example 1-10, by substituting a part of the main components such as Ni, Mn, and Co, between the 3b site and the 6C site It can be considered that the distance can be selectively set to an appropriate range, which can increase the output of the battery.

[Additional test]
In order to obtain knowledge about the ratio of the crystallite diameter determined by the Rietveld method (crystallite diameter / D50) to the average particle diameter (D50) determined by the laser diffraction / scattering particle size distribution measurement method, the following test was performed.

<Measurement of crystallite size by Rietveld method>
The Rietveld method is a method for refining the crystal structure parameters from the diffraction intensity obtained by powder X-ray diffraction or the like. This method assumes a crystal structure model, and refines various parameters of the crystal structure so that the X-ray diffraction pattern derived from the structure and the measured X-ray diffraction pattern match as much as possible.

  In the measurement of the X-ray diffraction pattern of this example, an X-ray diffractometer using Cu-Kα rays (D8 ADVANCE manufactured by Bruker AXS Co., Ltd.) was used, and analysis was performed using a FundamentalParameter. . Using the X-ray diffraction pattern obtained from the range of diffraction angle 2θ = 15 to 120 °, analysis software Topas Version 3 was used.

The crystal structure is attributed to the trigonal space group R-3m, with Li occupied at the 3a site, Mn, Co, Ni, and excess Li content x at the 3b site, and O occupied at the 6c site. The crystallite diameter (Gauss) and the crystal distortion (Gauss) were obtained. It is assumed that the isotropic temperature factor (Beq.) Is 1, and refinement is performed to Rwp <5.0 and GOF <1.3.
As a refinement procedure, Beq = 1 was fixed and the crystallite diameter (Gauss) was used as a variable, and repeated until each variable was not changed.

The above Rwp and GOF are values obtained by the following formulas (see: “Practice of powder X-ray analysis”, edited by Japan Analytical Chemistry X-ray Analysis Research Roundtable, published by Asakura Shoten. February 2002) 10 days, Table 6.2 of p107).
_{Rwp = [Σ i wi {yi} -fi (x) 2} / Σ i wiyi 2] 1/2
Re = [(NP) / Σ _i wiyi ² ] ^1/2
GOF = Rwp / Re
However, wi is a statistical weight, yi is an observation intensity, fi (x) is a theoretical diffraction intensity, N is the total number of data points, and P is the number of parameters to be refined.

Other specifications and conditions used for other measurements and Rietveld method analysis are as follows. In the analysis, it was assumed that the lithium transition metal oxide belonging to the trigonal crystal belongs to the hexagonal crystal.
Sample disp (mm): Refine
Generate Bond-lengths / errors: Refine
Detector: PSD
Detector Type: VANTEC-1
High Voltage: 5616V
Discr. Lower Level: 0.45V
Discr. Window Width: 0.15V
Grid Lower Level: 0.075V
Grid Window Width: 0.524V
Flood Field Correction: Disabled
Primary radius: 250mm
Secondary radius: 250mm
Receiving slit width: 0.1436626mm
Divergence angle: 0.3 °
Filament Length: 12mm
Sample Length: 25mm
Receiving Slit Length: 12mm
Primary Sollers: 2.623 °
Secondary Sollers: 2.623 °
Lorentzian, 1 / Cos: 0.01630098Th

Det. 1 voltage: 760.00V
Det. 1 gain: 80.000000
Det. 1 discr. 1 LL: 0.6900000
Det. 1 discr. 1 WW: 1.078000
Scan Mode: Continuous Scan
Scan Type: Locked Coupled
Spinner Speed: 15rpm
Divergence Slit: 0.300 °
Start: 15.000000
Time per step: 1s
Increment: 0.01460
#Steps: 7152
Generator voltage: 35kV
Generator current: 40 mA

<Measurement of average particle diameter (D50), 90% integrated diameter (D90)>
The particle size distribution of the sample (powder) was measured as follows.

Using a sample circulator for laser diffraction particle size distribution analyzer (“Microtorac ASVR” manufactured by Nikkiso Co., Ltd.), a sample (powder) is put into a water-soluble solvent, and ultrasonic waves of 40 watts are applied for 360 seconds at a flow rate of 40 mL / sec. After irradiation, the particle size distribution was measured using a laser diffraction particle size distribution measuring instrument “HRA (X100)” manufactured by Nikkiso Co., Ltd., and D50 and D90 were determined from the obtained volume-based particle size distribution chart.
The water-soluble solvent used in the measurement was water that passed through a 60 μm filter, the solvent refractive index was 1.33, the particle permeability was reflected, the measurement range was 0.122 to 704.0 μm, and the measurement time was The average value measured twice for 30 seconds was used as the measured value.

The average particle size (D50) obtained by the laser diffraction / scattering particle size distribution measurement method is the value obtained from image data such as an SEM image, at least in the case of a lithium transition metal oxide powder as in the present invention. It is possible to estimate. Here, the particle size distribution chart of the volume-based particle size distribution obtained by measuring with the laser diffraction particle size distribution measuring machine of the sample (average particle size D50 = 2.3 μm) obtained in Test Example 1 and its SEM image (magnification: 3 and 4 are shown in FIGS. 3 and 4, and the volume-based particle size distribution obtained by measuring with the laser diffraction particle size distribution measuring machine of the sample (average particle size D50 = 0.9 μm) obtained in Comparative Test Example 2 FIG. 5 and FIG. 6 show the particle size distribution chart and SEM image (magnification: 10,000 times). As can be seen by comparing these FIGS. 3-6, the particle diameter of the largest primary particle that can be confirmed by the SEM image is approximately the same as the average particle diameter (D50) obtained from the laser diffraction particle size distribution analyzer. Therefore, the average particle diameter (D50) obtained by the laser diffraction / scattering particle size distribution measurement method can be obtained instead by measuring the particle diameter of the largest primary particle in the SEM image.
In the case of a sample taken from an electrode, it is a mixture containing a conductive material, etc., but as described above, when ultrasonic waves are sufficiently dispersed over 360 seconds or more, laser diffraction particle size measurement It was confirmed that the particle size of the peak top of the chart of the volume-based particle size distribution obtained by measuring using a machine almost coincides with the average particle size (D50) of the lithium transition metal oxide powder used. Yes.

<Battery evaluation>
In a mortar, 8.0 g of the sample (powder) obtained in the test example and the comparative test example, 1.0 g of acetylene black (manufactured by Denki Kagaku Kogyo) as a conductive material, and 1.0 g of PVDF as a binder are placed. After mixing, 5 mL of N-methyl-2-pyrrolidone (NMP) was mixed and kneaded using a planetary stirring and defoaming device (Mazerustar KK-50S manufactured by Kurabo Industries) to obtain a paste.
This paste was applied onto an aluminum foil using a Baker type applicator having a clearance of 350 μm, dried, punched with a 14 mmφ punch, and pressed with a pressure of 4 t / cm ² to obtain a positive electrode plate. The weight of the positive electrode plate and the weight of only the aluminum foil punched with a 14 mmφ punch were subtracted, and the sample weight was calculated from the above mixed weight ratio. As a result, the sample weight in one positive electrode plate was 0.04 g.
The coin cell battery shown in FIG. 2 was prepared by using Li metal of Φ16 mm × 0.5 mm thickness for the negative electrode and 1M-LiPF ₆ / EC + DMC (3: 7 vol ratio) for the electrolyte. A test was conducted.

  In the cycle test 4, charging and discharging were repeated 30 times at 45 ° C. in the range of the electrode potential from 3.0 V to 4.3 V. The ratio of the discharge capacity after 30 cycles to the discharge capacity at the third cycle was defined as a cycle retention rate, and the relative value when the cycle retention rate of Comparative Test Example 1 was set to 100 was evaluated. Charging / discharging was performed at a constant current value corresponding to the 0.2C rate. The C rate represents a current value for charging / discharging the entire capacity of the battery over one hour as a 1C rate, and how many times the current value is charged / discharged. The 0.2C rate means charging / discharging at a current value 0.2 times the 1C rate, and indicates a current value for charging / discharging the entire battery capacity in 5 hours.

  In cycle test 5, charging and discharging were repeated 30 times at 45 ° C. in the range of SOC: 50 to 80%. The ratio of the discharge capacity at the 30th cycle to the discharge capacity at the 3rd cycle was defined as a cycle retention rate, and the relative value when the cycle retention rate of Comparative Test Example 1 was set to 100 was evaluated. Here, SOC means the depth of charge, and SOC 80% means charging at a current value of 0.2 C from the open circuit voltage to 4.1 V at 25 ° C. and then charging at a constant voltage of 4.3 V. It means a state of charge of 80% of the capacity.

  In the low-temperature capacity confirmation test 6, a charge / discharge cycle of charging and discharging in the range of 3.0 to 4.3 V at a constant current of 1 C rate at 0 ° C. was repeated, and the discharge capacity of the third cycle was measured, and a comparative test Evaluation was made based on relative values when the discharge capacity at the third cycle in Example 1 was 100.

The coin cell battery of FIG. 2 will be described.
A stainless steel current collector 13 is also spot welded inside a positive electrode case 11 made of stainless steel that is resistant to organic electrolyte. A positive electrode 15 made of the positive electrode mixture is pressure-bonded to the upper surface of the current collector 13. On the upper surface of the positive electrode 15, a separator 16 made of a microporous polypropylene resin impregnated with an electrolytic solution is disposed. In the opening of the positive electrode case, a sealing plate 12 having a negative electrode 14 made of metal Li bonded below is disposed with a polypropylene gasket 17 interposed therebetween, thereby sealing the battery. The sealing plate 12 serves as a negative electrode terminal and is made of stainless steel like the positive electrode case.
The battery diameter was 20 mm, and the total battery height was 3.2 mm. As the electrolytic solution, a mixture of ethylene carbonate and 1,3-dimethoxy carbonate in a volume ratio of 3: 7 was used as a solvent, and a solution obtained by dissolving 1 mol / L of LiPF ₆ as a solute was used.

(Test Example 1)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, nickel hydroxide with an average particle size (D50) of 25 μm, and cobalt oxyhydroxide with an average particle size (D50) of 14 μm In a molar ratio of Li: Mn: Ni: Co = 1.06: 0.31: 0.31: 0.32, added with water, mixed and stirred to a solid content concentration of 50 wt%. A slurry was prepared.
To the obtained slurry (raw material powder 20 kg), polycarboxylic acid ammonium salt (SN Dispersant 5468 manufactured by San Nopco Co., Ltd.) as a dispersant was added 6 wt% of the slurry solid content, and pulverized at 1300 rpm for 29 minutes with a wet pulverizer. The average particle size (D50) was 0.7 μm.
The obtained pulverized slurry was granulated and dried using a thermal spray dryer (spray dryer, OC-16 manufactured by Okawahara Chemical Co., Ltd.). At this time, a rotating disk was used for spraying, and granulation drying was performed by adjusting the temperature so that the rotation speed was 21,000 rpm, the slurry supply amount was 24 kg / hr, and the outlet temperature of the drying tower was 100 ° C.

  The obtained granulated powder was baked at 975 ° C. for 20 hours in the air using a stationary electric furnace. The fired powder obtained by firing is classified with a sieve having an opening of 75 μm, and the powder under the sieve is rotated by a classification rotor using a collision type pulverizer with a classification mechanism (Counterjet mill “100AFG / 50ATP” manufactured by Hosokawa Micron). Number: 14900 rpm, pulverization air pressure: 0.6 MPa, pulverization nozzle φ: 2.5 × 3 used, powder supply amount: 4.5 kg / h, pulverization, lithium transition metal oxide powder (sample )

About the obtained lithium transition metal oxide powder (sample), a volume-based particle size distribution chart is obtained using a laser diffraction particle size distribution measuring instrument (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. As a result, the particle size distribution was a mountain. That is, the differential inflection point was one point.
The average particle size (D50) of each raw material was determined from the volume-based particle size distribution chart obtained using the laser diffraction particle size distribution analyzer (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. It is the value of D50 obtained.

(Test Example 2)
The lithium transition metal oxide powder obtained in Test Example 1 was heat-treated in an atmosphere at 650 ° C. for 10 hours, classified with a sieve having an opening of 250 μm, and the sieve was collected to recover the lithium transition metal oxide. The treatment was performed in the same manner as in Test Example 1 except that powder (sample) was obtained.
About the obtained lithium transition metal oxide powder (sample), a volume-based particle size distribution chart is obtained using a laser diffraction particle size distribution measuring instrument (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. As a result, the particle size distribution was a mountain.

(Test Example 3)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, nickel hydroxide with an average particle size (D50) of 25 μm, and cobalt oxyhydroxide with an average particle size (D50) of 14 μm Were measured so that the molar ratio of Li: Mn: Ni: Co = 1.07: 0.30: 0.32: 0.31 and the firing temperature was 960 ° C. The same treatment was performed to obtain a lithium transition metal oxide powder (sample).
About the obtained lithium transition metal oxide powder (sample), a volume-based particle size distribution chart is obtained using a laser diffraction particle size distribution measuring instrument (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. As a result, the particle size distribution was a mountain.

(Test Example 4)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, nickel hydroxide with an average particle size (D50) of 25 μm, and cobalt oxyhydroxide with an average particle size (D50) of 14 μm And a molar ratio of Li: Mn: Ni: Co = 1.05: 0.31: 0.32: 0.32, except that the firing temperature is 950 ° C. and the heat treatment temperature is 600 ° C. Were processed in the same manner as in Test Example 2 to obtain a lithium transition metal oxide powder (sample).
About the obtained lithium transition metal oxide powder (sample), a volume-based particle size distribution chart is obtained using a laser diffraction particle size distribution measuring instrument (“Microtorac ASVR / HRA (X100)” manufactured by Nikkiso Co., Ltd.) as described above. As a result, the particle size distribution was a mountain.

(Test Example 5)
Li: Mn: Ni: Co in a molar ratio of lithium carbonate having an average particle diameter (D50) of 8 μm, manganese sulfate pentahydrate, nickel sulfate hexahydrate, and cobalt sulfate heptahydrate = 1.01: 0.33: 0.33: 0.33.

Place 2.5 L of city water in a 10 L airtight container (with oil jacket) with a stirrer, and add the above manganese sulfate pentahydrate, nickel sulfate hexahydrate, cobalt sulfate hexahydrate. It was dissolved and adjusted by adding water to 4 L.
25 wt% ammonia water (manufactured by Agata Chemical Industry Co., Ltd.) was added thereto, and a 6 mol / L aqueous sodium hydroxide solution was added while stirring the solution, and the pH was adjusted to 11.5 using a pH meter. The bath temperature was kept at 45 ° C. and stirred for 12 hours. The precipitate after stirring is repeatedly decanted and washed until the conductivity of the supernatant is 1 mS or less, and then the reaction solution is solid-liquid separated by filtration, and the solid content is dried at 120 ° C. for 10 hours to obtain a metal hydroxide raw material. Obtained.
The lithium carbonate was added to the obtained metal hydroxide raw material and mixed well with a ball mill to obtain a raw material mixed powder, and this raw material mixed powder was fired at 900 ° C. for 20 hours in the atmosphere to obtain a fired powder.
The obtained calcined powder was classified with a sieve having an opening of 75 μm, and the powder under the sieve was classified using a collision type pulverizer with a classification mechanism (counter jet mill “100AFG / 50ATP” manufactured by Hosokawa Micron), with a classification rotor rotation speed of 14900 rpm. The pulverization was performed under the conditions of a pulverization air pressure of 0.6 MPa, a pulverization nozzle φ2.5 × 3, and a powder supply amount of 4.5 kg / h.
The obtained powder was heat-treated in an atmosphere of 650 ° C. for 10 hours, classified with a sieve having an opening of 250 μm, and the sieve was collected to obtain a lithium transition metal oxide powder (sample).

(Comparative Test Example 1)
Li: Mn: Ni: Co = 1.01: 0.33 in a molar ratio of lithium carbonate, manganese sulfate pentahydrate, nickel sulfate hexahydrate, and cobalt sulfate hexahydrate : 0.33: 0.33: 0.33: After that, firing, classification, heat treatment, and classification were performed in the same manner as in Test Example 5 except that pulverization was not performed using a collision type pulverizer with a classification mechanism. Lithium transition metal oxide powder (sample) was obtained.

(Comparative Test Example 2)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, nickel hydroxide with an average particle size (D50) of 25 μm, and cobalt oxyhydroxide with an average particle size (D50) of 14 μm Are measured so that the molar ratio of Li: Mn: Ni: Co = 1.07: 0.31: 0.31: 0.31 is obtained, and then Tokyo Nara is used instead of the collision-type crusher with a classification mechanism. Lithium transition metal oxide powder (sample) was obtained by wet pulverization, dry granulation, firing and classification in the same manner as in Test Example 1 except that pulverization was performed using a production pin mill.

(Comparative Test Example 3)
Lithium carbonate with an average particle size (D50) of 8 μm, electrolytic manganese dioxide with an average particle size (D50) of 22 μm, nickel hydroxide with an average particle size (D50) of 25 μm, and cobalt oxyhydroxide with an average particle size (D50) of 14 μm And in a molar ratio of Li: Mn: Ni: Co = 1.05: 0.31: 0.32: 0.32, and then pulverization using a collision type pulverizer with a classification mechanism. Except for the above, wet pulverization, dry granulation, firing and classification were performed in the same manner as in Test Example 1 to obtain a lithium transition metal oxide powder (sample).

(Discussion)
As a result of Table 2, although all of Test Examples 1 to 5 did not show superior performance in the cycle test 4 compared to the conventional product (Comparative Test Example 1), the central region of the charge / discharge depth (for example, SOC 50-80%) ), The results of cycle test 5 in which charging and discharging were repeated showed that Test Examples 1 to 4 all showed superior performance compared to the conventional product (Comparative Test Example 1), and Test Example 5 was also the conventional product (Comparative). Results almost the same as those of Test Example 1) were obtained. Moreover, when the low temperature capacity | capacitance confirmation test 6, ie, the test for investigating an output characteristic, all the test examples 1-5 showed the outstanding performance compared with the conventional product (comparative test example 1).
As a result, it is important that the ratio of the crystallite diameter obtained by the Rietveld method to the average particle diameter (D50) obtained by the laser diffraction / scattering particle size distribution measurement method is 0.03 to 0.13. I understood.

  Regarding the relationship between the ratio of crystallite diameter / average particle diameter (D50) and the battery characteristics (life characteristics and output characteristics) when used in the central region of the charge / discharge depth, various tests are conducted. Although not confirmed, in the lithium transition metal oxide having a layer structure, by defining the ratio of crystallite diameter / average particle diameter (D50), the structure is stabilized with fewer active points in the particles, Furthermore, the internal diffusion of lithium ions during charge / discharge is improved, and the secondary particle size is small and the specific surface area is large, so the reaction area with the electrolyte is increased, and the current on the particle surface near the interface with the electrolyte is increased. This is thought to be due to the fact that the density is relaxed. In addition, it is considered to be related to stabilization by keeping resistance to volume expansion / contraction due to occlusion / desorption of lithium ions small due to difficulty in propagation of volume change due to charge / discharge.

The lithium transition metal oxide targeted in the above test example is represented by the general formula Li _{1 + x} M _1-xy M ′.
_y O _2-δ (wherein M is an element composed of any one element of Mn, Co and Ni or a combination of two or more of these elements. M ′ is an element derived from a Group 3 element in the periodic table) Although the composition is different from the lithium transition metal oxide represented by a transition element existing between group 11 elements or an element composed of a combination of two or more thereof, the relationship between the crystallite diameter and D50 The same can be said for.

Claims (7)

General formula Li _{1 + x} M _1-xy M ′ _y O _2−δ (wherein M is an element composed of any one element of Mn, Co and Ni, or a combination of two or more thereof. M ′ Is a lithium transition metal oxide represented by any one of Ti, Zr, Nb, Mo, W, or a combination of two or more thereof, and has a crystal structure of three directions in the space group R-3m Oxygen site occupancy determined by the Rietveld method is 0.982 <oxygen site occupancy ≦ 0.998, and the distance between 3b site and 6c site is 1.95 cm <3b site and 6c site. The distance between the particles is ≦ 2.05 mm, and the ratio of the crystallite diameter (crystallite diameter / D50) determined by the Rietveld method to the average particle diameter (D50) determined by the laser diffraction / scattering particle size distribution measurement method is 0.03˜ characterized in that it is a 0.13, Lithium transition metal oxide having a structure. 2. The lithium transition metal oxide according to claim 1, wherein the crystallite diameter determined by the Rietveld method is 0.01 μm to 0.50 μm. 3. The lithium transition metal oxide according to claim 1, wherein an average particle diameter (D50) obtained by a laser diffraction / scattering particle size distribution measurement method is 1.0 μm ≦ D50 ≦ 4.0 μm. 3. The lithium transition metal oxide according to claim 1, wherein an average particle diameter (D50) obtained by a laser diffraction / scattering particle size distribution measurement method is 2.0 μm ≦ D50 <3.0 μm. 5. The lithium transition metal oxide according to claim 1 , wherein the iron amount per weight of the lithium transition metal oxide is 0 ppb <iron amount <75 ppb. Lithium battery comprising a lithium transition metal oxide according as the positive electrode active material to claim 1. A lithium battery for an electric vehicle or a hybrid electric vehicle comprising the lithium transition metal oxide according to any one of claims 1 to 5 as a positive electrode active material.

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