JP4591716B2 - Lithium transition metal compound powder for positive electrode material of lithium secondary battery, production method thereof, spray-dried product, and calcined precursor, positive electrode for lithium secondary battery and lithium secondary battery using the same - Google Patents

Description

  The present invention relates to a lithium transition metal-based compound powder used as a positive electrode material for a lithium secondary battery, a method for producing the same, a spray-dried body, and a firing precursor, and a lithium secondary battery using the lithium transition metal-based compound powder The present invention relates to a positive electrode for a battery and a lithium secondary battery including the positive electrode for a lithium secondary battery.

  Lithium secondary batteries are excellent in energy density and output density, and are effective in reducing the size and weight. Therefore, the demand for power supplies for portable devices such as notebook computers, mobile phones, and handy video cameras is growing rapidly. ing. Lithium secondary batteries are also attracting attention as power sources for electric vehicles and power load leveling, and in recent years, demand for power sources for hybrid electric vehicles is rapidly expanding. In particular, in electric vehicle applications, it is necessary to be excellent in low cost, safety, life (particularly under high temperature) and load characteristics, and improvements in materials are desired.

Among the materials constituting the lithium secondary battery, as the positive electrode active material, a substance having a function capable of desorbing and inserting lithium ions can be used. There are various types of these positive electrode active material materials, each having its own characteristics. In addition, a common problem for improving performance is to improve load characteristics, and improvements in materials are strongly desired.
Furthermore, there is a demand for a material with a good performance balance that is excellent in low cost, safety, and life (particularly under high temperatures).

  Currently, lithium manganese composite oxides having a spinel structure, layered lithium nickel composite oxides, layered lithium cobalt composite oxides, and the like have been put into practical use as positive electrode active material materials for lithium secondary batteries. All of the lithium secondary batteries using these lithium-containing composite oxides have advantages and disadvantages in terms of characteristics. That is, a lithium manganese composite oxide having a spinel structure is inexpensive and relatively easy to synthesize, and is excellent in safety when used as a battery, but has a low capacity and inferior high-temperature characteristics (cycle and storage). Layered lithium-nickel composite oxides have high capacity and excellent high-temperature characteristics, but are difficult to synthesize, have inferior safety when used as batteries, and have drawbacks such as requiring careful storage. Layered lithium cobalt-based composite oxides are widely used as power sources for portable devices because they are easy to synthesize and have an excellent balance of battery performance. However, they are not sufficient in safety and costly. It is a drawback.

  Under such circumstances, lithium nickel manganese cobalt-based composite oxides having a layered structure have been overcome as disadvantages of these positive electrode active material materials as a potential candidate for active material materials that can overcome or be reduced as much as possible and have an excellent battery performance balance. Proposed. Particularly, in recent years, demands for lowering costs, higher voltages, and increasing safety demands are promising as positive electrode active material materials that can meet any of the demands.

However, the degree of cost reduction, higher voltage, and safety varies depending on the composition ratio. Therefore, further cost reduction, use with a higher upper limit voltage, and higher safety requirements Therefore, it is necessary to select and use one having a limited composition range, such as setting the manganese / nickel atomic ratio to 1 or more, or reducing the cobalt ratio. However, a lithium secondary battery using a lithium nickel manganese cobalt based composite oxide having such a composition range as a positive electrode material has reduced load characteristics such as rate and output characteristics. It was necessary.

Conventionally, with respect to lithium nickel manganese cobalt-based composite oxide having a composition range in which the manganese / nickel atomic ratio is 1 or more and the cobalt ratio is reduced to a value defined by the present invention or less, Patent Documents 1 to 3 and Non-Patent Documents 1 to 24.
However, according to Patent Documents 1 to 3 and Non-Patent Documents 1 to 24, there is no description relating to pore control of active material particles as defined by the present invention, and the necessary conditions for improving battery performance in the present invention. Therefore, it is extremely difficult to improve the battery performance as shown by the present invention only with these technologies.

On the other hand, Patent Document 4 discloses porous particles made of a lithium composite oxide mainly composed of one or more elements selected from the group consisting of Co, Ni, and Mn, and lithium. Particles having an average pore diameter in the pore distribution measurement in the range of 0.1 to 1 μm and a total volume of pores having a diameter of 0.01 to 1 μm being 0.01 cm ³ / g or more are non-aqueous. It is disclosed that it can be used as a positive electrode active material for a secondary battery, and this can improve the load characteristics of the battery without impairing the filling property of the positive electrode active material into the positive electrode.

However, the lithium composite oxide particles described in Patent Document 4 have a problem that the load characteristics are still insufficient, although the applicability is improved.
On the other hand, Patent Document 5 discloses lithium composite oxide particles whose mercury intrusion amount under a specific high-pressure load condition is not more than a predetermined upper limit in the measurement by mercury intrusion method, and the mercury intrusion described above. A sub-peak whose amount is equal to or greater than a predetermined lower limit or whose average pore radius is within a predetermined range, and in which the peak top exists in a specific pore radius region in addition to the conventional main peak in the pore distribution curve When the lithium composite oxide particles having a lithium secondary oxide particle are used as a positive electrode material for a lithium secondary battery, the low temperature load characteristics of the lithium secondary battery can be improved, and the coating property at the time of producing the positive electrode is excellent and suitable. It is described that it can be a positive electrode material for a lithium secondary battery.

However, the lithium composite oxide particles described in Patent Document 5 show an improvement effect with a composition having a relatively large cobalt ratio, but the load characteristics are still insufficient for the composition range defined by the present invention. was there.
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  That is, the object of the present invention is to improve load characteristics such as rate and output characteristics when used as a positive electrode material for a lithium secondary battery, and more preferably to reduce costs, increase voltage resistance, and increase safety. Lithium transition metal-based compound powder for lithium secondary battery positive electrode material and method for producing the same, positive electrode for lithium secondary battery using this lithium transition metal-based compound powder, and positive electrode for lithium secondary battery It is providing a lithium secondary battery provided with.

  As a result of intensive studies to achieve the above-mentioned problems, the inventors of the present invention have controlled the powder properties so that the mercury intrusion amount during pressurization by the mercury intrusion method is within the above range in the lithium transition metal compound, and By controlling so that the peak of the pore distribution curve has the characteristics as described above, as a lithium secondary battery positive electrode material, in addition to cost reduction, high voltage resistance, high safety, load such as rate and output characteristics The inventors have found that lithium transition metal-based compound powders that can be compatible with improved characteristics can be obtained, and the present invention has been completed.

That is, the lithium transition metal compound powder for a lithium secondary battery positive electrode material of the present invention has a mercury intrusion amount of 0.8 cm ³ in a mercury intrusion curve by a mercury intrusion method at a pressure of 3.86 kPa to 413 MPa. / g or more, ^{3 cm} 3 / g Ri der hereinafter, bulk density and wherein 0.5 to 1.5 g / cm ³ der Rukoto (claim 1).
Here, the lithium transition metal-based compound powder of the present invention has a main distribution peak in a pore distribution curve by a mercury intrusion method having a peak top at a pore radius of 300 nm or more and 1000 nm or less, and a pore radius of 80 nm. As described above, it is preferable not to have a sub-peak in which a peak top exists below 300 nm.

The lithium transition metal-based compound powder of the present invention has a pore volume of 0.5 cm ³ related to a main peak having a peak top at a pore radius of 300 nm or more and 1000 nm or less in a pore distribution curve by a mercury intrusion method. / G or more and 1.5 cm ³ / g or less is preferable (Claim 3).
The lithium transition metal compound powder of the present invention is ultrasonically dispersed for 5 minutes using a laser diffraction / scattering particle size distribution measuring device with a refractive index of 1.24 and a particle size standard as a volume standard. It is preferable that the median diameter measured after output 30 W and frequency 22.5 kHz is 0.6 μm or more and 5 μm or less.

Moreover, it is preferable that the lithium transition metal type compound powder of the present invention is a lithium nickel manganese cobalt type composite oxide represented by the following composition formula (I).
Li [Li _{z / (2 + z)} {(Li _x Ni _{(1-3x) / 2} Mn _{(1 + x) / 2} ) _1-y Co _y } _{2 / (2 + z)} ] O ₂ ... composition formula (I )
(However, 0 ≦ x ≦ 0.33
0 ≦ y ≦ 0.2
−0.02 ≦ z ≦ 0.2 (1-y) (1-3x))
Further, the lithium transition metal-based compound powder of the present invention preferably has a bulk density of 0.5 to 1.5 g / cm ³ (Claim 6).

The lithium transition metal compound powder of the present invention preferably has a BET specific surface area of 1.5 to ⁵ m ² / g (Claim 7).
Further, the lithium transition metal compound powder of the present invention preferably has a C value of 0.005 wt% or more and 0.2 wt% or less when the content carbon concentration is C (wt%) ( Claim 8).

The method for producing a lithium transition metal compound powder of the present invention is obtained by pulverizing a lithium compound and at least one or more transition metal compounds in a liquid medium, and spray-drying a slurry in which these are uniformly dispersed. The spray-dried product is fired in an oxygen-containing gas atmosphere (claim 9) .

In the method for producing a lithium transition metal compound powder according to the present invention, the lithium compound is preferably lithium carbonate .

The positive electrode for a lithium secondary battery of the present invention has a positive electrode active material layer containing such a lithium transition metal-based compound powder of the present invention and a binder on a current collector (claim). Item 11 ).
The lithium secondary battery of the present invention is a lithium secondary battery comprising a negative electrode capable of inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a positive electrode capable of inserting and extracting lithium. Such a positive electrode for a lithium secondary battery of the present invention is used (claim 12 ).

  When the lithium transition metal-based compound for a lithium secondary battery positive electrode material of the present invention is used as a lithium secondary battery positive electrode material, it is possible to achieve both reduction in cost and safety and improvement in load characteristics. For this reason, according to the present invention, a lithium secondary battery that is inexpensive, highly safe, and excellent in performance even when used at a high charging voltage is provided.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. However, the description of constituent elements described below is an example (representative example) of an embodiment of the present invention, and is not specified by these contents.
[Lithium transition metal compound powder]
The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material of the present invention has a mercury intrusion amount of 0.8 cm ³ / g at a pressure of 3.86 kPa to 413 MPa in a mercury intrusion curve by a mercury intrusion method. The above is 3 cm ³ / g or less.

<Mercury intrusion method>
The lithium transition metal compound powder for a lithium secondary battery positive electrode material of the present invention is characterized by satisfying a specific condition in measurement by a mercury intrusion method. Therefore, before describing the particles of the present invention, the mercury intrusion method will be briefly described first.
The mercury intrusion method is a method for obtaining information such as specific surface area and pore size distribution from the relationship between pressure and the amount of mercury intruded into a pore of a sample such as porous particles while applying pressure. It is.

  Specifically, first, the container containing the sample is evacuated and filled with mercury. Mercury has a high surface tension, and as it is, mercury does not penetrate into the pores on the sample surface, but when pressure is applied to the mercury and the pressure is gradually increased, the pores increase in size from the smallest to the smallest. Gradually mercury enters the pores. If a change in the mercury liquid level (that is, the amount of mercury intruded into the pores) is detected while the pressure is continuously increased, a mercury intrusion curve representing the relationship between the pressure applied to the mercury and the amount of mercury intruded can be obtained. .

Here, assuming that the pore shape is cylindrical, the radius is r, the surface tension of mercury is δ, and the contact angle is θ, the size in the direction of pushing mercury out of the pore is −2πrδ (cos θ). (If θ> 90 °, this value is positive). Moreover, since the magnitude of the force in the direction of pushing mercury into the pores under the pressure P is represented by πr ² P, the following formulas (1) and (2) are derived from the balance of these forces. It will be.

  In the case of mercury, values of surface tension δ = 480 dyn / cm and contact angle θ = 140 ° are generally used. When these values are used, the radius of the pore into which mercury is injected under the pressure P is expressed by the following formula (3).

  That is, since there is a correlation between the pressure P applied to mercury and the radius r of the pore into which mercury enters, the size of the pore radius of the sample and its volume are calculated based on the obtained mercury intrusion curve. A pore distribution curve representing the relationship can be obtained. For example, when the pressure P is changed from 0.1 MPa to 100 MPa, the pores in the range from about 7500 nm to about 7.5 nm can be measured.

Note that the approximate measurement limit of the pore radius by the mercury intrusion method is that the lower limit is about 2 nm or more and the upper limit is about 200 μm or less, and the pores in a relatively large range compared to the nitrogen adsorption method described later. It can be said that it is suitable for analysis of distribution.
Measurement by the mercury intrusion method can be performed using an apparatus such as a mercury porosimeter. Specific examples of the mercury porosimeter include an autopore manufactured by Micromeritics, a pore master manufactured by Quantachrome, and the like.

The particles of the present invention are characterized in that, in the mercury intrusion curve by this mercury intrusion method, the amount of mercury intrusion at the time of pressure increase from 3.86 kPa to 413 MPa is 0.8 cm ³ / g or more and 3 cm ³ / g or less. To do. Mercury intrusion volume is usually 0.8 cm ³ / g or more, preferably 0.85 cm ³ / g or more, more preferably 0.9 cm ³ / g or more, and most preferably 1.0 cm ³ / g or more, usually 3 cm ³ / G or less, preferably 2.5 cm ³ / g or less, more preferably 2 cm ³ / g or less, and most preferably 1.8 cm ³ / g or less. When the upper limit of this range is exceeded, the voids become excessive, and when the particles of the present invention are used as the positive electrode material, the filling rate of the positive electrode active material into the positive electrode plate is lowered, and the battery capacity is restricted. On the other hand, if the lower limit of the range is not reached, voids between the particles become excessively small. Therefore, when a battery is produced using the particles of the present invention as a positive electrode material, lithium diffusion between particles is inhibited and load characteristics are deteriorated. To do.

In the particles of the present invention, when a pore distribution curve is measured by a mercury intrusion method described later, a specific main peak described below usually appears.
In the present specification, the “pore distribution curve” refers to the total pore volume per unit weight (usually 1 g) of pores having a radius equal to or larger than the radius of the pores on the horizontal axis, The value obtained by differentiating the logarithm of the pore radius is plotted on the vertical axis, and is usually expressed as a graph connecting the plotted points. In particular, the pore distribution curve obtained by measuring the particles of the present invention by the mercury intrusion method is appropriately referred to as “the pore distribution curve according to the present invention” in the following description.

In this specification, “main peak” refers to the largest peak among the peaks of the pore distribution curve, and “sub peak” refers to a peak other than the main peak of the pore distribution curve.
In the present specification, “peak top” refers to the point at which the coordinate value of the vertical axis takes the largest value in each peak of the pore distribution curve.

<Main peak>
The main peak of the pore distribution curve according to the present invention has a peak top whose pore radius is usually 300 nm or more, preferably 310 nm or more, most preferably 325 nm or more, and usually 1000 nm or less, preferably 950 nm or less. Preferably it exists in 900 nm or less, More preferably, it is 850 nm or less, Most preferably, it exists in the range of 800 nm or less. When the upper limit of this range is exceeded, when the battery is made using the porous particles of the present invention as the positive electrode material, lithium diffusion in the positive electrode material is inhibited, or the conductive path is insufficient, and the load characteristics may be reduced. There is sex.

  On the other hand, below the lower limit of this range, when a positive electrode is produced using the porous particles of the present invention, the necessary amount of conductive material and binder increases, and the positive electrode plate (positive electrode current collector) is increased. The filling rate of the active material is restricted, and the battery capacity may be restricted. In addition, with the formation of fine particles, the mechanical properties of the coating film at the time of coating become hard or brittle, and there is a possibility that the coating film is likely to be peeled off during the winding process during battery assembly.

Further, the pore volume of the main peak of the pore distribution curve according to the present invention is preferably usually 0.5 cm ³ / g or more, preferably 0.52cm ³ / g or more, more preferably 0.55 cm ³ / g or more, most preferably 0.57cm ³ / g or more and usually 1.5 cm ³ / g or less, preferably ^{1 cm} 3 / g or less, more preferably 0.8 cm ³ / g or less, and most preferably 0. 7 cm ³ / g or less. When the upper limit of this range is exceeded, the voids become excessive, and when the particles of the present invention are used as the positive electrode material, the positive electrode active material filling rate into the positive electrode plate may be low, and the battery capacity may be limited. is there. On the other hand, if the lower limit of this range is not reached, voids between the particles become excessively small. Therefore, when a battery is produced using the particles of the present invention as a positive electrode material, lithium diffusion between secondary particles is inhibited, and load characteristics are reduced. May be reduced.

<Sub-peak>
The pore distribution curve according to the present invention may have a plurality of sub-peaks in addition to the main peak described above, but does not exist within a pore radius range of 80 nm or more and 300 nm or less. To do.

<composition>
The lithium transition metal compound of the present invention is a compound having a structure capable of desorbing and inserting Li ions, and examples thereof include sulfides, phosphate compounds, and lithium transition metal composite oxides. . Examples of sulfides include compounds having a two-dimensional layered structure such as TiS ₂ and MoS ₂ , and strong compounds represented by the general formula Me _x Mo ₆ S ₈ (Me is various transition metals including Pb, Ag, and Cu). Examples thereof include a sugar compound having a three-dimensional skeleton structure. Examples of the phosphate compound include those belonging to the olivine structure, and are generally represented by LiMePO ₄ (Me is at least one or more transition metals), specifically LiFePO ₄ , LiCoPO ₄ , LiNiPO ₄ , Examples include LiMnPO ₄ . Examples of the lithium transition metal composite oxide include spinel structures capable of three-dimensional diffusion and those belonging to a layered structure capable of two-dimensional diffusion of lithium ions. Those having a spinel structure are generally expressed as LiMe ₂ O ₄ (Me is at least one transition metal), specifically, LiMn ₂ O ₄ , LiCoMnO ₄ , LiNi _0.5 Mn _1.5 O. ₄ and CoLiVO ₄ . Those having a layered structure are generally expressed as LiMeO ₂ (Me is at least one or more transition metals), specifically, LiCoO ₂ , LiNiO ₂ , LiNi _1-x Co _x O ₂ , LiNi _{1-x. -y Co x Mn y O 2,} LiNi 0.5 Mn 0.5 O 2, Li 1.2 Cr 0.4 Mn 0.4 O 2, Li 1.2 Cr 0.4 Ti 0.4 O 2, Examples include LiMnO ₂ .

The lithium transition metal-based compound of the present invention preferably includes a crystal structure belonging to an olivine structure, a spinel structure, or a layered structure from the viewpoint of lithium ion diffusion. Among these, those including a crystal structure belonging to a layered structure are particularly preferable.
Here, the layered structure will be described in more detail. As a typical crystal system having a layered structure, there are those belonging to the α-NaFeO ₂ type such as LiCoO ₂ and LiNiO ₂ , which are hexagonal and have a space group due to their symmetry.

(Hereinafter referred to as “layered R (−3) m structure”).
However, the layered LiMeO ₂ is not limited to the layered R (−3) m structure. In addition to this, LiMnO ₂ called so-called layered Mn is an orthorhombic and space-group Pm2m layered compound, and Li ₂ MnO ₃ called so-called 213 phase is Li [Li _1/3 Mn _2/3 ]. O ₂ , which is a monoclinic space group C2 / m structure, is also a layered compound in which a Li layer, a [Li _1/3 Mn _2/3 ] layer, and an oxygen layer are stacked.

Here, the chemical meaning of the Li composition (z and x) in the lithium transition metal compound of the present invention will be described in more detail below.
As described above, the layered structure is not necessarily limited to the R (-3) m structure, but is preferably one that can be attributed to the R (-3) m structure from the viewpoint of electrochemical performance. In order to explain in detail, the following description will be made assuming that the layered structure is an R (-3) m structure.

In the present invention, among lithium transition metals having a layered structure,
The ratio of Li [Ni _1/2 Mn _1/2 ] O ₂ is (1-3x) (1-y),
The ratio of Li [Li _1/3 Mn _2/3 ] O ₂ is 3x (1-y),
The ratio of LiCoO ₂ is y
Layered lithium transition metal composite oxide, which is assumed to be a solid solution, ie, [Li] ^(3a) [Li _x Ni _{(1-3x) / 2} Mn _{(1 + x) / 2} ) _(1-y) Co _y ] ^{( 3b)} O ₂ (II)
Those having a basic structure are preferred.

Here, (3a) and (3b) represent different metal sites in the layered R (-3) m structure, respectively.
However, in the present invention, Li is added in excess of z mol with respect to the composition of the formula (II), and is dissolved.
^{_{[Li] (3a) [Li}} z / (2 + z) {Li x Ni (1-3x) / 2 Mn (1 + x) / 2) (1-y) Co y} 2 / (2 + z)] (3b) O 2 (I)
(However, 0 ≦ x ≦ 0.33, 0 ≦ y ≦ 0.2, −0.02 ≦ z ≦ 0.2 (1-y) (1-3x)), (3a), (3b) Each represent a different metal site in the layered R (-3) m structure. )
The lithium transition metal represented by these is preferable.

In addition, this notation indicates that, in a layered lithium transition metal composite oxide expressed as LiMeO ₂ (Me is a transition metal), when an excess Li of z moles is dissolved in a transition metal site (3b site), [Li] ^(3a) [Li _{z / (2 + z)} Me _{2 / (2 + z)} ] ^(3b) O ₂
It is expressed in the same way as what is expressed.
In order to obtain x, y, and z in the composition formula of the lithium transition metal compound, each transition metal and Li are analyzed by an inductively coupled plasma emission spectrometer (ICP-AES), and Li / Ni / Mn / Co It is calculated by calculating the ratio of. That is, x and y are determined by the Ni / Mn and Co / Ni ratios, and z is the Li / Ni molar ratio Li / Ni = {2 + 2z + 2x (1-y)} / {(1-3x) (1-y) }
It can be obtained from

  From a structural point of view, it is considered that both Li related to z and Li related to x are substituted by the same transition metal site. Here, the difference between Li related to x and Li related to z is whether or not the valence of Ni is greater than two (whether or not trivalent Ni is generated). That is, since x is a value linked with the Mn / Ni ratio (Mn rich degree), the Ni valence does not vary only by this x value, and Ni remains divalent. On the other hand, z can be regarded as Li that increases the Ni valence, and z is an index of the Ni valence (the ratio of Ni (III)).

  When the Ni valence (m) accompanying the change in z is calculated from the above composition formula, it is assumed that the Co valence is trivalent and the Mn valence is tetravalent, and m = 2z / {(1- y) (1-3x)} + 2. This calculation result means that the Ni valence is not determined only by z but is a function of x and y. If z = 0, the Ni valence remains divalent regardless of the values of x and y. When z is a negative value, it means that the amount of Li contained in the active material is less than the stoichiometric amount, and those having a very large negative value may not have the effect of the present invention. There is sex. On the other hand, even if the z value is the same, it means that the Ni valence increases as the composition is rich in Mn (x value is large) and / or Co rich (y value is large). The rate characteristics and output characteristics are improved, but on the other hand, the capacity tends to decrease. From this, it can be said that the upper limit of the z value is more preferably defined as a function of x and y as described above.

In addition, when the y value is in the range of 0 ≦ y ≦ 0.2 and the amount of Co is small, in addition to reducing the cost, it was used as a lithium secondary battery designed to be charged at a high charging potential. In some cases, cycle characteristics and safety are improved.
As described above, the battery using the lithium transition metal compound powder having the above composition as the positive electrode active material has a disadvantage that the conventional rate and output performance are inferior, but the lithium nickel cobalt composite oxide of the present invention is mercury. The amount of mercury intrusion at the time of pressurization in the press-in curve is large, and the pore capacity between crystal particles is large. Therefore, the load characteristics necessary as the positive electrode active material can be improved.

-Lithium nickel manganese cobalt complex oxide The lithium transition metal compound for the lithium secondary battery positive electrode material of the present invention is preferably a lithium nickel manganese cobalt complex oxide and includes a crystal structure belonging to a layered structure. More preferably, the composition is represented by the following formula (I).

Li [Li _{z / (2 + z)} {(Li _x Ni _{(1-3x) / 2} Mn _{(1 + x) / 2} ) _1-y Co _y } _{2 / (2 + z)} ] O ₂ ... composition formula (I )
(However, 0 ≦ x ≦ 0.33
0 ≦ y ≦ 0.2
−0.02 ≦ z ≦ 0.2 (1-y) (1-3x))
In the above formula (I), the value of z is −0.02 or more, preferably −0.01 or more, more preferably 0 or more, still more preferably 0.01 (1-y) (1−3x) or more, Preferably it is 0.02 (1-y) (1-3x) or more, 0.2 (1-y) (1-3x) or less, preferably 0.19 (1-y) (1-3x) or less. More preferably, it is 0.18 (1-y) (1-3x) or less, and most preferably 0.17 (1-y) (1-3x) or less. If the lower limit is not reached, the conductivity will decrease, and if the upper limit is exceeded, the amount of substitution to the transition metal site will increase so much that the battery capacity will be reduced. is there.

On the other hand, if z is too large, the carbon dioxide absorbability of the active material powder increases, so that it becomes easy to absorb carbon dioxide in the atmosphere. As a result, it is estimated that the concentration of contained carbon increases.
On the other hand, if z is too small, the amount of Li for forming a layer mainly composed of a layered structure is clearly insufficient, and it is estimated that a different phase such as a spinel phase appears.
The value of x is 0 or more and 0.33 or less, preferably 0.30 or less, more preferably 0.25 or less, and most preferably 0.20 or less. If the lower limit is not reached, stability at a high voltage is lowered, and safety is easily lowered. If the upper limit is exceeded, a heterogeneous phase is likely to be generated, or battery performance may be degraded.

The value of y is 0 or more, preferably 0.01 or more and 0.2 or less, preferably 0.18 or less, more preferably 0.15 or less, and most preferably 0.1 or less.
In the composition range of the above formula (I), the closer the z value is to the lower limit that is a constant ratio, the lower the rate characteristics and output characteristics of the battery, and the lower the z value is to the upper limit, Although the rate characteristics and output characteristics of the battery are improved, there is a tendency for the capacity to decrease. Moreover, the lower the x value, that is, the closer the manganese / nickel atomic ratio is to 1, the lower the charge voltage, the higher the capacity, but there is a tendency that the cycle characteristics and safety of the battery set with a higher charge voltage tend to decrease. In addition, the closer the x value is to the upper limit, the more the cycle characteristics and safety of the battery set at a higher charge voltage are improved, while the discharge capacity, rate characteristics, and output characteristics tend to decrease. In addition, the closer the y value is to the lower limit, the lower the load characteristics such as the rate characteristics and output characteristics when the battery is used. Conversely, the closer the y value is to the upper limit, the rate characteristics when the battery is used. However, the cycle characteristics and safety when set at a high charging voltage are lowered, and the raw material cost tends to increase. The present invention has been completed as a result of intensive studies to overcome this conflicting tendency, and it is important that the composition parameters x, y, and z are within specified ranges.

In the composition of the formula (I), the atomic ratio of the oxygen amount is described as 2 for convenience, but there may be some non-stoichiometry. For example, the atomic ratio of oxygen can be in the range of 2 ± 0.1.
When the lithium transition metal compound of the present invention is a lithium nickel manganese cobalt composite oxide powder, a substitution element may be introduced into the structure. The substitution element is selected from any one or more of Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, Nb, Zr, Mo, W, and Sn. These substitution elements are appropriately replaced with Ni, Mn, and Co elements in a range of 20 atomic% or less.

<Reason why the particles of the present invention provide the above effects>
Since the lithium composite oxide particles of the present invention have a moderately large pore volume, it is possible to increase the contact area between the surface of the positive electrode active material and the electrolytic solution when a battery is produced using this. It is presumed that the load characteristics necessary as the positive electrode active material have been improved.

<Other preferred embodiments>
In the following description, the other characteristics of the particles of the present invention will be described in detail. However, this is only a preferable aspect, and the other characteristics of the particles of the present invention are particularly limited as long as the above characteristics are provided. It is not done.

<Median diameter and 90% integrated diameter ( _D90 )>
The median diameter of the lithium transition metal based compound powder of the present invention is usually 0.6 μm or more, preferably 0.8 μm or more, more preferably 1 μm or more, most preferably 1.1 μm or more, and usually 5 μm or less, preferably 4. It is 5 μm or less, more preferably 4 μm or less, still more preferably 3.5 μm or less, and most preferably 3 μm or less. If the lower limit is not reached, there may be a problem in applicability at the time of forming the positive electrode active material layer, and if the upper limit is exceeded, battery performance may be lowered.

The 90% cumulative diameter (D ₉₀ ) of the secondary particles of the lithium transition metal-based compound powder of the present invention is usually 10 μm or less, preferably 9 μm or less, more preferably 8 μm or less, most preferably 7 μm or less, and usually 1 μm. The thickness is preferably 2 μm or more, more preferably 3 μm or more, and most preferably 3.5 μm or more. If the upper limit is exceeded, battery performance may be reduced, and if the lower limit is not reached, there may be a problem in applicability when forming the positive electrode active material layer.

In the present invention, the median diameter and the 90% integrated diameter (D ₉₀ ) as the average particle diameter are set to a refractive index of 1.24 using a known laser diffraction / scattering particle size distribution measuring device, and the particle diameter standard is determined. Measured as a volume reference. In the present invention, a 0.1 wt% sodium hexametaphosphate aqueous solution was used as a dispersion medium used in the measurement, and measurement was performed after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz).

<The bulk density>
The bulk density of the lithium transition metal compound powder for a lithium secondary battery positive electrode material of the present invention is usually 0.5 g / cc or more, preferably 0.6 g / cc or more, more preferably 0.7 g / cc or more, most preferably. Is 0.8 g / cc or more. Below this lower limit, the powder filling property and electrode preparation may be adversely affected, and the positive electrode using this as an active material is usually 1.5 g / cc or less, preferably 1.4 g / cc or less, more preferably Is 1.3 g / cc or less, most preferably 1.2 g / cc or less. While the bulk density exceeding this upper limit is preferable for improving powder filling properties and electrode density, the specific surface area may become too low, and battery performance may be reduced.
In the present invention, the bulk density is a powder obtained when 5 to 10 g of lithium nickel manganese cobalt composite oxide powder as a lithium transition metal compound is placed in a 10 ml glass graduated cylinder and tapped 200 times with a stroke of about 20 mm. Body filling density (tap density) g / cc was determined.

<BET specific surface area>
The lithium nickel manganese composite oxide powder of the present invention also has a BET specific surface area of usually 1.5 m ² / g or more, preferably 1.7 m ² / g or more, more preferably 2 m ² / g or more, most preferably 2.5 m ² / g or more, usually 5 m ² / g or less, preferably 4.5 m ² / g or less, more preferably 4 m ² / g or less, and most preferably 3.5 m ² / g or less. If the BET specific surface area is smaller than this range, the battery performance is likely to be lowered, and if it is larger, the bulk density is difficult to increase, and there is a possibility that a problem is likely to occur in the coating property at the time of forming the positive electrode active material.

  The BET specific surface area can be measured by a known BET type powder specific surface area measuring device. In the present invention, an OMS Riken: AMS8000 type automatic powder specific surface area measuring device was used, nitrogen was used as an adsorption gas, and helium was used as a carrier gas. Specifically, the powder sample is heated and deaerated with a mixed gas at a temperature of 150 ° C., then cooled to liquid nitrogen temperature to adsorb the nitrogen / helium mixed gas, and then heated to room temperature with water. The adsorbed nitrogen gas was desorbed, the amount was detected by a heat conduction detector, and the specific surface area of the sample was calculated from this.

<Contained carbon concentration C>
The C value of the lithium transition metal compound powder of the present invention is usually 0.005% by weight or more, preferably 0.01% by weight or more, more preferably 0.015% by weight or more, and most preferably 0.02% by weight. These are usually 0.2% by weight or less, preferably 0.15% by weight or less, more preferably 0.12% by weight or less, and most preferably 0.1% by weight or less. If the lower limit is not reached, battery performance may be reduced. If the upper limit is exceeded, swelling due to gas generation when the battery is produced may increase or battery performance may be reduced.

In the present invention, the carbon concentration C of the lithium transition metal-based compound powder is determined by measurement by an oxygen gas combustion (high-frequency heating furnace type) infrared absorption method, as shown in the Examples section below.
In addition, from the carbon concentration contained in the lithium lithium transition metal compound powder obtained by the carbon analysis described later, in the lithium transition metal compound powder analyzed by ion chromatography and the numerical value assuming that the carbon is all derived from carbonate ions Therefore, the C value can be regarded as indicating information on the amount of carbonate compound, particularly lithium carbonate.

On the other hand, like lithium iron phosphate compounds (general formula: LiFePO ₄ ), the active material itself may be compounded with carbon to impart conductivity to a compound having extremely low electron conductivity, Even if it is a high lithium transition metal compound, when it is combined with conductive carbon as a method for further enhancing the electronic conductivity, a C amount exceeding the above specified range may be detected. The C value of the lithium transition metal-based compound powder when such a treatment is performed is not limited to the specified range.
On the other hand, in the lithium transition metal compound powder defined by the present invention, a very small amount of lithium is present as carbonate, and does not affect the lithium composition (x, z) defined by the composite oxide powder. .

<Average primary particle size>
The average primary particle diameter of the lithium transition metal compound of the present invention is preferably 0.05 μm or more and 1 μm or less. The lower limit is more preferably 0.1 μm or more, further preferably 0.15 μm or more, most preferably 0.2 μm or more, and the upper limit is more preferably 0.8 μm or less, still more preferably 0.7 μm or less, most preferably Is 0.6 μm or less. When the above upper limit is exceeded, the powder filling property is adversely affected or the specific surface area is reduced, so that there is a possibility that the battery performance such as rate characteristics and output characteristics may be lowered. If the lower limit is not reached, there is a possibility that problems such as inferior reversibility of charge / discharge due to the undeveloped crystals.

  In addition, the average particle diameter of the primary particle in this invention is an average diameter observed with the scanning electron microscope (SEM), and the particle diameter of about 10-30 primary particles using a 30,000 times SEM image. It can be calculated as an average value.

<Volume resistivity>
The lower limit of the volume resistivity value when the lithium transition metal compound of the present invention is compacted at a pressure of 40 MPa is preferably 1 × 10 ³ Ω · cm or more, more preferably 5 × 10 ³ Ω · cm or more. 1 × 10 ⁴ Ω · cm or more is more preferable. The upper limit is preferably 5 × 10 ⁷ Ω · cm or less, more preferably 1 × 10 ⁷ Ω · cm or less, and further preferably 5 × 10 ⁶ Ω · cm or less. If this volume resistivity exceeds this upper limit, the load characteristics when used as a battery may be reduced. On the other hand, if the volume resistivity is below this lower limit, the safety of the battery may be reduced.

  In the present invention, the volume resistivity of the lithium transition metal based compound powder is such that the four probe / ring electrode, the electrode spacing is 5.0 mm, the electrode radius is 1.0 mm, the sample radius is 12.5 mm, and the applied voltage limiter is 90 V. The volume resistivity measured in a state where the lithium transition metal-based compound powder is compacted at a pressure of 40 MPa. The volume resistivity can be measured, for example, by using a powder resistance measuring device (for example, Lorester GP powder resistance measuring system manufactured by Dia Instruments Co., Ltd.) with a powder probe unit on a powder under a predetermined pressure. It can be carried out.

<Powder X-ray diffraction peak>
The lithium transition metal-based compound powder of the present invention preferably does not have a diffraction peak at 2θ = 31 ± 1 ° in a powder X-ray diffraction pattern using CuKα rays. Here, “does not include” includes those having a diffraction peak that does not adversely affect the battery performance of the present invention. That is, this diffraction peak is derived from the spinel phase, but if the spinel phase is included, the capacity, rate characteristics, high-temperature storage characteristics, and high-temperature cycle characteristics of the battery are reduced. For this reason, the diffraction peak may have a diffraction peak that does not adversely affect the battery performance of the present invention, but 2θ = 31 based on the (003) peak area of 2θ = 18.5 ± 1 ° The diffraction peak area at ± 1 ° is preferably 0.5% or less, more preferably 0.2% or less, and particularly preferably no diffraction peak at all. In other words, this diffraction peak is derived from the spinel phase, and if the spinel phase is included, the capacity, rate characteristics, high-temperature storage characteristics, and high-temperature cycle characteristics of the battery tend to deteriorate, so there is no such diffraction peak. Is preferred.

[Method for producing lithium transition metal compound]
The method for producing a lithium transition metal compound in the present invention is not limited to a specific production method. For example, a lithium nickel manganese cobalt composite oxide will be described as an example. A slurry in which a compound and a cobalt compound are dispersed in a liquid medium can be spray-dried, and then the mixture can be fired.

Hereinafter, a method for producing a lithium nickel manganese cobalt composite oxide powder as a lithium transition metal compound of the present invention will be described in detail.
Among the raw material compounds used for the preparation of the slurry in producing the lithium nickel manganese cobalt based composite oxide by the method of the present invention, the lithium compounds include Li ₂ CO ₃ , LiNO ₃ , LiNO ₂ , LiOH, LiOH · H. ₂ O, LiH, LiF, LiCl, LiBr, LiI, CH ₃ OOLi, Li ₂ O, Li ₂ SO ₄ , dicarboxylic acid Li, citric acid Li, fatty acid Li, alkyllithium and the like can be mentioned. Preferred among these lithium compounds, in that upon firing process does not generate toxic substances such as SO _x, NO _x, nitrogen atom or sulfur atom, a lithium compound containing no halogen atoms, also at the time of firing It is a compound that tends to form voids by generating cracked gas in the secondary particles of the spray-dried powder by generating cracked gas. Taking these points into consideration, Li ₂ CO ₃ , LiOH in particular LiOH.H ₂ O is easy to handle and relatively inexpensive, and Li ₂ CO ₃ is preferable. These lithium compounds may be used alone or in combination of two or more. Also good.

As the nickel _{compound, Ni (OH) 2, NiO} , NiOOH, NiCO 3,
2NiCO ₃ .3Ni (OH) ₂ .4H ₂ O, NiC ₂ O ₄ .2H ₂ O, Ni (NO ₃ ) ₂ .6H ₂ O, NiSO ₄ , NiSO ₄ .6H ₂ O, fatty acid nickel, nickel halide, etc. Is mentioned. Among these, in that upon firing process does not generate toxic substances such as SO _x, NO _X,
Nickel compounds such as Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ , 2NiCO ₃ .3Ni (OH) ₂ .4H ₂ O, NiC ₂ O ₄ .2H ₂ O are preferred. Further, Ni (OH) ₂ , NiO from the viewpoint of being available as an industrial raw material at a low cost and having high reactivity.
Ni (OH) ₂ , NiOOH, NiCO ₃ , and Ni (OH) ₂ are particularly preferable from the viewpoint of easily forming voids in the secondary particles of the spray-dried powder by generating decomposition gas during firing.
NiOOH, NiCO ₃ . These nickel compounds may be used individually by 1 type, and may use 2 or more types together.

Further, as the manganese compound, manganese oxides such as Mn ₂ O ₃ , MnO ₂ , Mn ₃ O ₄ , M
Examples include nCO ₃ , Mn (NO ₃ ) ₂ , MnSO ₄ , manganese acetate, manganese dicarboxylate, manganese citrate, manganese salts such as manganese fatty acid, oxyhydroxides, halides such as manganese chloride, and the like. Among these manganese compounds, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ , and MnCO ₃ do not generate gases such as SO _x and NO _x during firing, and can be obtained at low cost as industrial raw materials. Therefore, it is preferable. Furthermore, these manganese compounds may be used individually by 1 type, and may use 2 or more types together.

Cobalt compounds include Co (OH) ₂ , CoOOH, CoO, Co ₂ O ₃ , C
o ₃ O ₄ , Co (OCOCH ₃ ) ₂ .4H ₂ O, CoCl ₂ , Co (NO ₃ ) ₂ .6H ₂ O, Co
(SO ₄ ) ₂ · 7H ₂ O, CoCO _{3 and the} like. Among them, SO _x , N during the firing process
Co (OH) ₂ , CoOOH, CoO, Co ₂ O ₃ , Co ₃ O ₄ , and CoCO ₃ are preferable in that no harmful substances such as O _x are generated. Co (OH) ₂ and CoOOH are highly reactive. In addition, Co (OH) ₂ , CoOOH, and CoCO ₃ are particularly preferable from the viewpoint that voids are easily formed in the secondary particles of the spray-dried powder due to generation of decomposition gas during firing. These cobalt compounds may be used individually by 1 type, and may use 2 or more types together.

  In addition to the above Li, Ni, Mn, and Co raw material compounds, other elements are substituted to introduce the above-mentioned foreign elements, and voids in secondary particles formed by spray drying described later are efficiently formed. It is possible to use a group of compounds intended to be used. In addition, the addition stage of the compound used for the purpose of efficiently forming the voids of the secondary particles used here can be selected either before or after mixing the raw materials depending on the property. It is. In particular, it is preferable to add a compound that is easily decomposed due to mechanical shear stress applied by the mixing step after the mixing step.

The method for mixing the raw materials is not particularly limited, and may be wet or dry. For example, a method using an apparatus such as a ball mill, a vibration mill, or a bead mill can be used. Wet mixing in which the raw material compound is mixed in a liquid medium such as water or alcohol is preferable because more uniform mixing is possible and the reactivity of the mixture can be increased in the firing step.
The mixing time varies depending on the mixing method, but it is sufficient that the raw materials are uniformly mixed at the particle level. For example, in a ball mill (wet or dry type), usually about 1 to 2 days, and in a bead mill (wet continuous method) Is usually about 0.1 to 6 hours.

In the raw material mixing stage, it is preferable that the raw material is pulverized in parallel. As the degree of pulverization, the particle diameter of the raw material particles after pulverization is an index, but the average particle diameter (median diameter) is usually 0.3 μm or less, preferably 0.25 μm or less, and most preferably 0.2 μm or less. . If the average particle size of the pulverized raw material particles is too large, the reactivity in the firing process is lowered and the composition is difficult to be uniformized. However, making particles smaller than necessary leads to an increase in pulverization cost, so that the average particle size is usually 0.01 μm or more, preferably 0.02 μm or more, more preferably 0.05 μm or more. It ’s fine. A means for realizing such a degree of pulverization is not particularly limited, but a wet pulverization method is preferable. Specific examples include dyno mill.
The median diameter of the pulverized particles in the slurry described in the examples of the present invention is set to a refractive index of 1.24 by a known laser diffraction / scattering particle size distribution measuring apparatus, and the particle diameter reference is set to the volume reference. Measured. In the present invention, a 0.1 wt% sodium hexametaphosphate aqueous solution was used as a dispersion medium used in the measurement, and measurement was performed after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz). The median diameter of the spray-dried body described later is the same as that except that the measurement was performed after ultrasonic dispersion for 0, 1, 3, and 5 minutes, respectively.

<Spray drying process>
After the wet mixing, it is then usually subjected to a drying process. The method is not particularly limited, but spray drying is preferable from the viewpoints of uniformity of the generated particulate matter, powder flowability, powder handling performance, and efficient production of dry particles.

[Spray-dried powder]
In the method for producing a lithium nickel manganese cobalt based composite oxide powder of the present invention, a powder obtained by agglomerating primary particles to form secondary particles is obtained by pulverizing by wet pulverization and then spray drying. . The spray-dried powder formed by agglomerating primary particles to form secondary particles is a geometric feature of the spray-dried powder of the present invention. Examples of the shape confirmation method include SEM observation and cross-sectional SEM observation.

  The median diameter (value measured without applying ultrasonic dispersion) of the powder obtained by spray drying which is also a firing precursor of the lithium nickel manganese cobalt based composite oxide powder of the present invention is usually 15 μm or less, more preferably Is 12 μm or less, more preferably 9 μm or less, and most preferably 7 μm or less. However, since it tends to be difficult to obtain a too small particle size, it is usually 3 μm or more, preferably 4 μm or more, more preferably 5 μm or more. In the case of producing a particulate material by the spray drying method, the particle size can be controlled by appropriately selecting the spray format, the pressurized gas flow supply rate, the slurry supply rate, the drying temperature, and the like.

  In addition, the spray-dried powder of lithium nickel manganese cobalt based composite oxide powder according to the present invention is characterized by a weak cohesion between primary particles, which examines changes in median diameter accompanying ultrasonic dispersion. Can be confirmed. Here, the upper limit of the median diameter of spray-dried particles when measured after applying ultrasonic dispersion “Ultra Sonic” (output 30 W, frequency 22.5 kHz) for 5 minutes is usually 4 μm or less, preferably 3.5 μm or less. More preferably, it is 3 μm or less, more preferably 2.5 μm or less, most preferably 2 μm or less, and the lower limit is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, most preferably It is 0.2 μm or more. Lithium nickel manganese cobalt composite oxide particles fired using spray-dried particles having a median diameter after ultrasonic dispersion larger than the above value have few voids between the particles, and the load characteristics are not improved. On the other hand, lithium nickel manganese cobalt-based composite oxide particles fired using spray-dried particles whose median diameter after ultrasonic dispersion is smaller than the above values have too many voids between them, resulting in a decrease in bulk density. There is a possibility that problems such as poor coating properties may occur.

  Further, the bulk density of the spray-dried powder of the lithium nickel manganese cobalt composite oxide powder for a lithium secondary battery positive electrode material of the present invention is usually 0.1 g / cc or more, preferably 0.3 g / cc or more, more preferably 0.5 g / cc or more, most preferably 0.7 g / cc or more. Below this lower limit, there is a possibility of adversely affecting powder filling properties and powder handling, and is usually 1.7 g / cc or less, preferably 1.6 g / cc or less, more preferably 1.5 g / cc. Hereinafter, it is most preferably 1.4 g / cc or less. The bulk density exceeding this upper limit is preferable for powder filling properties and powder handling, but the specific surface area may be too low, and the reactivity in the firing step may be reduced.

In addition, if the powder obtained by spray drying has a small specific surface area, the reactivity between the raw material compounds is reduced in the next firing step, so as described above, the starting material is pulverized before spray drying, etc. It is preferable that the specific surface area be increased as much as possible by the above means. On the other hand, excessively high specific surface area is not only industrially disadvantageous, but also may result in failure to obtain the lithium transition metal compound of the present invention. Accordingly, the spray-dried particles thus obtained have a BET specific surface area of usually 10 m ² / g or more, preferably 20 m ² / g or more, more preferably 30 m ² / g or more, most preferably 35 m ² / g or more. Usually, it is preferably 70 m ² / g or less, preferably 65 m ² / g or less, and most preferably 60 m ² / g or less.

Here, in the present invention, the “firing precursor” means a lithium transition metal compound precursor before firing obtained by treating a spray-dried body. For example, a decomposition gas may be generated or sublimated during the above-described firing to form a compound that forms voids in the secondary particles, and the spray-dried body may be used as the firing precursor.
The fired precursor thus obtained is then fired. This firing condition depends on the composition and the lithium compound raw material used, but as a tendency, if the firing temperature is too high, the primary particles grow too much. Conversely, if the firing temperature is too low, the crystal structure becomes undeveloped, and the specific surface area is low. Too big. The firing temperature is usually 800 ° C. or higher, preferably 850 ° C. or higher, more preferably 900 ° C. or higher, most preferably 950 ° C. or higher, and usually 1100 ° C. or lower, preferably 1075 ° C. or lower, more preferably 1050 ° C. or lower, Most preferably, it is 1025 degrees C or less.

  For firing, for example, a box furnace, a tubular furnace, a tunnel furnace, a rotary kiln or the like can be used. The firing process is usually divided into three parts: temperature increase, maximum temperature retention, and temperature decrease. The second maximum temperature holding portion is not necessarily limited to one time, and may include two or more stages depending on the purpose, which means that aggregation is eliminated to the extent that secondary particles are not destroyed. The temperature raising, maximum temperature holding, and temperature lowering steps may be repeated twice or more with a crushing step or a pulverization step which means crushing to primary particles or even fine powder.

  In the temperature raising step, the temperature in the furnace is usually raised at a temperature raising rate of 1 ° C./min to 10 ° C./min. Even if this rate of temperature rise is too slow, it takes time and is industrially disadvantageous. However, if it is too fast, the furnace temperature does not follow the set temperature depending on the furnace. The rate of temperature rise is preferably 2 ° C./min or more, more preferably 3 ° C./min or more, preferably 7 ° C./min or less, more preferably 5 ° C./min or less.

  Although the holding time in the maximum temperature holding step varies depending on the temperature, it is usually 30 minutes or more, preferably 3 hours or more, more preferably 5 hours or more, most preferably 6 hours or more within the above-mentioned temperature range, and 50 Time or less, preferably 25 hours or less, more preferably 20 hours or less, and most preferably 15 hours or less. If the firing time is too short, it becomes difficult to obtain a lithium nickel manganese cobalt based composite oxide powder with good crystallinity, and it is not practical to be too long. If the firing time is too long, it will be disadvantageous because it will be necessary to crush afterwards or it will be difficult to crush.

In the temperature lowering step, the temperature in the furnace is usually decreased at a temperature lowering rate of 0.1 ° C./min to 10 ° C./min. If it is too slow, it takes time and is industrially disadvantageous. However, if it is too fast, the uniformity of the object tends to be lacking or the deterioration of the container tends to be accelerated. The temperature lowering rate is preferably 1 ° C./min or more, more preferably 3 ° C./min or more, preferably 7 ° C./min or less, more preferably 5 ° C./min or less.
As the atmosphere during firing, an oxygen-containing gas atmosphere such as air can be used. Usually, the atmosphere has an oxygen concentration of 1% by volume or more, preferably 10% by volume or more, more preferably 15% by volume or more, and 100% by volume or less, preferably 50% by volume or less, more preferably 25% by volume or less.

In such a production method, in order to produce the lithium transition metal-based compound powder having the specific composition of the present invention, a lithium compound, a nickel compound, a manganese compound, and cobalt can be used when the production conditions are constant. The target Li / Ni / Mn / M molar ratio can be controlled by adjusting the mixing ratio of each compound when preparing a slurry in which the compound is dispersed in a liquid medium.
According to the lithium transition metal-based compound thus obtained, the balance of performance is low, with low swelling due to gas generation, high capacity, excellent load characteristics such as rate and output, excellent low-temperature output characteristics, and storage characteristics. A positive electrode material for a lithium secondary battery is provided.

[Positive electrode for lithium secondary battery]
The positive electrode for a lithium secondary battery of the present invention is formed by forming a positive electrode active material layer containing a lithium nickel manganese composite oxide powder for a lithium secondary battery positive electrode material of the present invention and a binder on a current collector. Is.
The positive electrode active material layer is usually formed by mixing a positive electrode material, a binder, and a conductive material and a thickener, which are used as necessary, in a dry form into a sheet shape, and then pressing the positive electrode current collector on the positive electrode current collector. Alternatively, these materials are dissolved or dispersed in a liquid medium to form a slurry, which is applied to the positive electrode current collector and dried.

  As the material for the positive electrode current collector, metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, and carbon materials such as carbon cloth and carbon paper are usually used. Of these, metal materials are preferable, and aluminum is particularly preferable. As for the shape, in the case of a metal material, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, etc., and in the case of a carbon material, a carbon plate, a carbon thin film, a carbon cylinder Etc. Among these, metal thin films are preferable because they are currently used in industrialized products. In addition, you may form a thin film suitably in mesh shape.

  When a thin film is used as the positive electrode current collector, its thickness is arbitrary, but it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 100 mm or less, preferably 1 mm or less, more preferably 50 μm or less. The range of is preferable. If it is thinner than the above range, the strength required for the current collector may be insufficient. On the other hand, if it is thicker than the above range, the handleability may be impaired.

  The binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material that is stable with respect to the liquid medium used during electrode production may be used. Specific examples include polyethylene, Resin polymers such as polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose, SBR (styrene butadiene rubber), NBR (acrylonitrile butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, ethylene・ Rubber polymers such as propylene rubber, styrene / butadiene / styrene block copolymers and hydrogenated products thereof, EPDM (ethylene / propylene / diene terpolymers), styrene / ethylene / butadiene / ethylene copolymers, Styrene / isoprene styrene bromide Copolymer and its hydrogenated thermoplastic elastomeric polymer, syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer, etc. Fluorine polymers such as soft resinous polymers, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymers, ion conductivity of alkali metal ions (especially lithium ions) And a polymer composition having the same. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  The ratio of the binder in the positive electrode active material layer is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, and usually 80% by weight or less, preferably 60% by weight or less. More preferably, it is 40% by weight or less, and most preferably 10% by weight or less. If the proportion of the binder is too low, the positive electrode active material cannot be sufficiently retained and the positive electrode has insufficient mechanical strength, which may deteriorate battery performance such as cycle characteristics. Battery capacity and conductivity may be reduced.

  The positive electrode active material layer usually contains a conductive material in order to increase conductivity. There are no particular restrictions on the type, but specific examples include metal materials such as copper and nickel, graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, and amorphous carbon such as needle coke. And carbon materials. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios. The proportion of the conductive material in the positive electrode active material layer is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 1% by weight or more, and usually 50% by weight or less, preferably 30%. % By weight or less, more preferably 20% by weight or less. If the proportion of the conductive material is too low, the conductivity may be insufficient, and conversely if it is too high, the battery capacity may be reduced.

  As the liquid medium for forming the slurry, it is possible to dissolve or disperse the lithium nickel manganese composite oxide powder that is the positive electrode material, the binder, and the conductive material and the thickener used as necessary. As long as it is a possible solvent, the type is not particularly limited, and either an aqueous solvent or an organic solvent may be used. Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N , N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran (THF), toluene, acetone, dimethyl ether, dimethylacetamide, hexamethylphosphalamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, etc. be able to. In particular, when an aqueous solvent is used, a dispersant is added together with the thickener, and a slurry such as SBR is slurried. In addition, these solvents may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

The content of the lithium transition metal-based compound powder of the present invention as the positive electrode material in the positive electrode active material layer is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, and usually 99%. .9% by weight or less, preferably 99% by weight or less. If the proportion of the lithium transition metal compound powder in the positive electrode active material layer is too large, the strength of the positive electrode tends to be insufficient, and if it is too small, the capacity may be insufficient.
The thickness of the positive electrode active material layer is usually about 10 to 200 μm.
The positive electrode active material layer obtained by coating and drying is preferably consolidated by a roller press or the like in order to increase the packing density of the positive electrode active material.
Thus, the positive electrode for a lithium secondary battery of the present invention can be adjusted.

[Lithium secondary battery]
The lithium secondary battery of the present invention includes the above-described positive electrode for a lithium secondary battery of the present invention capable of occluding and releasing lithium, a negative electrode capable of occluding and releasing lithium, and a non-aqueous electrolyte using a lithium salt as an electrolytic salt, Is provided. Further, a separator for holding a nonaqueous electrolyte may be provided between the positive electrode and the negative electrode. In order to effectively prevent a short circuit due to contact between the positive electrode and the negative electrode, it is desirable to interpose a separator in this way.

<Negative electrode>
The negative electrode is usually configured by forming a negative electrode active material layer on a negative electrode current collector, similarly to the positive electrode.
As a material of the negative electrode current collector, a metal material such as copper, nickel, stainless steel, nickel-plated steel, or a carbon material such as carbon cloth or carbon paper is used. Among these, in the case of a metal material, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, etc., and in the case of a carbon material, a carbon plate, a carbon thin film, a carbon cylinder, etc. are mentioned. Among these, metal thin films are preferable because they are currently used in industrialized products. In addition, you may form a thin film suitably in mesh shape. When a metal thin film is used as the negative electrode current collector, the preferred thickness range is the same as the range described above for the positive electrode current collector.

The negative electrode active material layer includes a negative electrode active material. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions, but it can usually occlude and release lithium from the viewpoint of high safety. A carbon material is used.
Although there is no restriction | limiting in particular as a carbon material, The graphite (graphite), such as artificial graphite and natural graphite, and the thermal decomposition thing of organic substance on various thermal decomposition conditions are mentioned. Examples of pyrolysis products of organic matter include coal-based coke, petroleum-based coke, coal-based pitch carbide, petroleum-based pitch carbide, or carbide obtained by oxidizing these pitches, needle coke, pitch coke, phenol resin, crystalline cellulose, etc. And carbon materials obtained by partially graphitizing these, furnace black, acetylene black, pitch-based carbon fibers, and the like. Among them, graphite is preferable, and particularly preferable is artificial graphite, purified natural graphite, or graphite material containing pitch in these graphites manufactured by subjecting easy-graphite pitch obtained from various raw materials to high-temperature heat treatment. Therefore, those subjected to various surface treatments are mainly used. One of these carbon materials may be used alone, or two or more thereof may be used in combination.

When a graphite material is used as the negative electrode active material, the d value (interlayer distance) of the lattice plane (002 plane) determined by X-ray diffraction by the Gakushin method is usually 0.335 nm or more, and usually 0.34 nm or less, preferably Is preferably 0.337 nm or less.
Further, the ash content of the graphite material is usually 1% by weight or less, particularly 0.5% by weight or less, and particularly preferably 0.1% by weight or less, based on the weight of the graphite material.

Further, the crystallite size (Lc) of the graphite material determined by X-ray diffraction by the Gakushin method is usually 30 nm or more, preferably 50 nm or more, and particularly preferably 100 nm or more.
The median diameter of the graphite material determined by the laser diffraction / scattering method is usually 1 μm or more, especially 3 μm or more, more preferably 5 μm or more, especially 7 μm or more, and usually 100 μm or less, especially 50 μm or less, more preferably 40 μm or less, especially 40 μm or less. It is preferable that it is 30 micrometers or less.

Moreover, the BET specific surface area of the graphite material is usually 0.5 m ² / g or more, preferably 0.7 m ² / g or more, more preferably 1.0 m ² / g or more, and further preferably 1.5 m ² / g. or more, and usually 25.0 m ² / g or less, preferably 20.0 m ² / g, more preferably 15.0 m ² / g or less, still more preferably 10.0 m ² / g or less.
Further, when performing Raman spectroscopy using argon laser light for graphite material, and strength _{I A} of the peak _{P A} is detected in the range of 1580～1620Cm ^-1, it is detected in the range of 1350 ^-1 that intensity ratio _I a / _{I B} of the intensity _{I B} of a peak _{P B} is what is preferably 0 to 0.5. Further, the half width of the peak _{P A} is preferably 26cm ^-1 or less, 25 cm ^-1 or less is more preferable.

In addition to the above-mentioned various carbon materials, it can also be used as a negative electrode active material of other materials capable of inserting and extracting lithium. Specific examples of negative electrode active materials other than carbon materials include metal oxides such as tin oxide and silicon oxide, nitrides such as Li _2.6 Co _0.4 N, and lithium alloys such as lithium alone and lithium aluminum alloys. Can be mentioned. One of these materials other than the carbon material may be used alone, or two or more thereof may be used in combination. Moreover, you may use in combination with the above-mentioned carbon material.
As in the case of the positive electrode active material layer, the negative electrode active material layer is usually prepared by slurrying the above-described negative electrode active material, a binder, and optionally a conductive material and a thickener in a liquid medium. It can manufacture by apply | coating to a negative electrode electrical power collector, and drying. As the liquid medium, the binder, the thickener, the conductive material, and the like that form the slurry, the same materials as those described above for the positive electrode active material layer can be used.

<Nonaqueous electrolyte>
As the non-aqueous electrolyte, for example, known organic electrolytes, polymer solid electrolytes, gel electrolytes, inorganic solid electrolytes, and the like can be used. Of these, organic electrolytes are preferable. The organic electrolytic solution is configured by dissolving a solute (electrolyte) in an organic solvent.

  Here, the type of the organic solvent is not particularly limited. For example, carbonates, ethers, ketones, sulfolane compounds, lactones, nitriles, chlorinated hydrocarbons, ethers, amines, esters, amides. A phosphoric acid ester compound or the like can be used. Typical examples include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene carbonate, ethylene carbonate, vinylene carbonate, vinyl ethylene carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 4-methyl-2- Pentanone, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile Benzonitrile, butyronitrile, valeronitrile, 1,2-dichloroethane, dimethylformamide, dimethyl sulfoxide, trimethyl phosphate, triethyl phosphate, etc. Et compounds, hydrogen atoms may be partially substituted with a halogen atom. Moreover, these single or 2 or more types of mixed solvents can be used.

  The organic solvent described above preferably contains a high dielectric constant solvent in order to dissociate the electrolytic salt. Here, the high dielectric constant solvent means a compound having a relative dielectric constant of 20 or more at 25 ° C. Among the high dielectric constant solvents, it is preferable that ethylene carbonate, propylene carbonate, and compounds in which hydrogen atoms thereof are substituted with other elements such as halogen or alkyl groups are contained in the electrolytic solution. The proportion of the high dielectric constant solvent in the electrolyte is preferably 20% by weight or more, more preferably 25% by weight or more, and most preferably 30% by weight or more.

If the content of the high dielectric constant solvent is less than the above range, desired battery characteristics may not be obtained.
In addition, in the organic electrolyte, a gas such as CO ₂ , N ₂ O, CO, and SO ₂ , vinylene carbonate, polysulfide S _x ^{2−, and the} like that enables efficient charge and discharge of lithium ions on the negative electrode surface You may add the additive which forms a film in arbitrary ratios. Of these, vinylene carbonate is particularly preferable.

The type of the electrolytic salt is not particularly limited, and any conventionally known solute can be used. Specific examples include LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , LiBOB, LiCl, LiBr, CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₃ CF ₃ ) _{2 and the} like. Any one of these electrolytic salts may be used alone, or two or more thereof may be used in any combination and ratio. In addition, any ratio of an additive that forms a good film that enables efficient charge and discharge of lithium ions on the negative electrode surface, such as gas such as CO ₂ , N ₂ O, CO, SO ₂ , and polysulfide S _x ²⁻ May be added.

The lithium salt of the electrolytic salt is usually contained in the electrolytic solution so as to have a concentration of 0.5 mol / L to 1.5 mol / L. Even if it is less than 0.5 mol / L or more than 1.5 mol / L, the electrical conductivity may be lowered, and the battery characteristics may be adversely affected. The lower limit is preferably 0.75 mol / L or more and the upper limit is 1.25 mol / L or less.
Even when a polymer solid electrolyte is used, the type thereof is not particularly limited, and any known crystalline / amorphous inorganic substance can be used as the solid electrolyte. Examples of the crystalline inorganic solid electrolyte include LiI, Li ₃ N, Li _{1 + x} J _x Ti _2-x (PO ₄ ) ₃ (J = Al, Sc, Y, La), Li _0.5-3x RE _{0. .5 + x} TiO ₃ (RE = La, Pr, Nd, Sm) and the like. Moreover, as an amorphous inorganic solid electrolyte, for example, 4.9L
Examples include oxide glasses such as iI-34.1 Li ₂ O-61B ₂ O ₅ and 33.3Li ₂ O-66.7SiO ₂ . Any one of these may be used alone, or two or more may be used in any combination and ratio.

<Separator>
When the above-described organic electrolyte is used as the electrolyte, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit between the electrodes. The material and shape of the separator are not particularly limited, but those that are stable with respect to the organic electrolyte used, have excellent liquid retention properties, and can reliably prevent short-circuiting between electrodes are preferable. Preferable examples include microporous films, sheets, nonwoven fabrics and the like made of various polymer materials. Specific examples of the polymer material include polyolefin polymers such as nylon, cellulose acetate, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, polypropylene, polyethylene, and polybutene. In particular, from the viewpoint of chemical and electrochemical stability, which is an important factor for separators, polyolefin polymers are preferable. From the viewpoint of self-occluding temperature, which is one of the purposes of use of separators in batteries, polyethylene is preferred. Is particularly desirable.

  When using a separator made of polyethylene, it is preferable to use ultra-high molecular weight polyethylene from the viewpoint of maintaining high-temperature shape, and the lower limit of the molecular weight is preferably 500,000, more preferably 1,000,000, and most preferably 1,500,000. On the other hand, the upper limit of the molecular weight is preferably 5 million, more preferably 4 million, and most preferably 3 million. This is because if the molecular weight is too large, the fluidity becomes too low, and the pores of the separator may not close when heated.

<Battery shape>
The lithium secondary battery of the present invention is produced by assembling the above-described positive electrode for a lithium secondary battery of the present invention, a negative electrode, an electrolyte, and a separator used as necessary into an appropriate shape. Furthermore, other components such as an outer case can be used as necessary.
The shape of the lithium secondary battery of the present invention is not particularly limited, and can be appropriately selected from various commonly employed shapes according to the application. Examples of commonly used shapes include a cylinder type with a sheet electrode and separator in a spiral shape, an inside-out cylinder type with a combination of pellet electrode and separator, and a coin type with a stack of pellet electrode and separator. Can be mentioned. The method for assembling the battery is not particularly limited, and can be appropriately selected from various commonly used methods according to the shape of the target battery.

<Charge potential of the positive electrode when fully charged>
In addition, the lithium secondary battery of the present invention is preferably designed so that the initial charge potential of the positive electrode in a fully charged state is 4.5 V (vs. Li ^/ Li ⁺ ) or higher. That is, the lithium transition metal-based compound powder for a lithium secondary battery positive electrode material of the present invention is charged at a high charging potential of 4.5 V (vs. Li ^/ Li ⁺ ) or more for the first time according to the specific composition described above. When used as a lithium secondary battery designed in the above, it effectively exhibits the effect of improving cycle characteristics and safety. However, it is also possible to use the charging potential as less than 4.5V.

  The general embodiment of the lithium secondary battery of the present invention has been described above. However, the lithium secondary battery of the present invention is not limited to the above-described embodiment, and various modifications are possible as long as the gist thereof is not exceeded. Can be implemented.

Examples The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples unless it exceeds the gist.
[Method for measuring physical properties]
The physical properties and the like of lithium transition metal-based compound powders produced in each Example and Comparative Example described below were measured as follows.

Composition (Li / Ni / Mn / Co):
It was determined by ICP-AES analysis.
Measurement of various physical properties by mercury intrusion method:
As a measuring device by the mercury intrusion method, Autopore III9420 manufactured by Micromeritics was used. Moreover, as measurement conditions of the mercury intrusion method, measurement was performed while increasing the pressure from 3.86 kPa to 413 MPa at room temperature. The mercury surface tension value was 480 dyn / cm, and the contact angle value was 141.3 °.

Average primary particle size:
It calculated | required from the SEM image of 30,000 times.
Secondary particle median diameter:
Measurements were made after 5 minutes of ultrasonic dispersion.
The bulk density:
4 to 10 g of the sample powder was put into a 10 ml glass graduated cylinder, and the powder packing density when tapped 200 times with a stroke of about 20 mm was obtained.

Specific surface area:
Obtained by BET method.
Contained carbon concentration C:
An EMIA-520 carbon sulfur analyzer manufactured by HORIBA, Ltd. was used. A sample of several tens to 100 mg was weighed into an air-baked magnetic crucible, a combustion aid was added, and carbon was extracted by combustion in a high-frequency heating furnace in an oxygen stream. CO ₂ in the combustion gas was quantified by non-dispersive infrared absorption spectrophotometry. For sensitivity calibration, 150-15 low alloy steel No. 1 (C guaranteed value: 0.469% by weight) manufactured by Japan Iron and Steel Federation was used.

Volume resistivity:
Using a powder resistivity measurement device (Dia Instruments: Lorester GP powder low efficiency measurement system PD-41), the sample weight is 3 g, and a powder probe unit (four probe / ring electrode, electrode spacing 5.0 mm) The electrode resistivity is 1.0 mm, the sample radius is 12.5 mm, and the applied voltage limiter is 90 V. The volume resistivity [Ω · cm] of the powder under various pressures is measured, and the volume resistivity under a pressure of 40 MPa is measured. The values were compared.

Crystal phase:
It calculated | required by the powder X-ray-diffraction pattern using a CuK alpha ray.
[Powder X-ray Diffraction Measuring Device] PANalytical PW1700
[Measurement conditions] X-ray output: 40 kV, 30 mA, scanning axis: θ / 2θ
Scanning range (2θ): 10.0-90.0 °
Measurement mode: Continuous
Reading width: 0.05 °, scanning speed: 3.0 ° / min.
Slit: DS 1 °, SS 1 °, RS 0.2mm
Median diameter of pulverized particles in slurry:
Using a known laser diffraction / scattering particle size distribution measuring device, the refractive index was set to 1.24, and the particle diameter standard was measured as the volume standard. In addition, 0.1% by weight sodium hexametaphosphate aqueous solution is used as a dispersion medium, and ultrasonic dispersion for 5 minutes (output 30 W, frequency 22.5 kHz)
Measurements were made later.

Median diameter as an average particle diameter of the raw material Li ₂ CO ₃ powder:
Using a known laser diffraction / scattering particle size distribution measuring apparatus (LA-920, manufactured by Horiba, Ltd.), the refractive index was set to 1.24, and the particle diameter standard was measured as a volume standard. Further, ethyl alcohol was used as a dispersion medium, and measurement was performed after ultrasonic dispersion for 5 minutes (output 30 W, frequency 22.5 kHz).

Physical properties of particulate powder obtained by spray drying:
The form was confirmed by SEM observation and cross-sectional SEM observation. The median diameter and 90% cumulative diameter (D ₉₀ ) as the average particle diameter are set to a refractive index of 1.24 using a known laser diffraction / scattering particle size distribution measuring device (LA-920, manufactured by Horiba, Ltd.) The particle diameter standard was measured using the volume standard. Further, a 0.1 wt% sodium hexametaphosphate aqueous solution was used as a dispersion medium, and measurement was performed after 0 minutes, 1 minute, 3 minutes, and 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz). The specific surface area was determined by the BET method. The bulk density was determined as the powder packing density when 4 to 6 g of sample powder was put in a 10 ml glass graduated cylinder and tapped 200 times with a stroke of about 20 mm.

[Production of Lithium Transition Metal Compound Powder (Examples and Comparative Examples)]
Example 1
Li ₂ CO ₃ , Ni (OH) ₂ , and Mn ₃ O ₄ were weighed so as to have a molar ratio of Li: Ni: Mn = 1.267: 0.250: 0.583, mixed, and then mixed. Pure water was added to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Particulate powder obtained by spray-drying the slurry with a spray dryer, about 15 g, was charged into an alumina crucible, fired at 950 ° C. for 12 hours in an air atmosphere (heating rate 5 ° C./min.), And then crushed. The volume resistivity is 3.7 × 10 ⁶ Ω · cm, the carbon concentration is 0.092 wt%, and the composition is Li _1.088 (Li _0.167 Ni _0.254 Mn _0.579 ) O ₂ . Lithium nickel manganese composite oxide (x = 0.167, y = 0, z = 0.088) was obtained. The average primary particle diameter is 0.2 μm, the median diameter is 1.7 μm, the 90% cumulative diameter (D ₉₀ ) is 3.6 μm, the bulk density is 0.8 g / cc, and the BET specific surface area is 3.1 m ² / g. Met.

(Example 2)
Li ₂ CO ₃ , Ni (OH) ₂ , and Mn ₃ O ₄ were weighed so as to have a molar ratio of Li: Ni: Mn = 1.267: 0.250: 0.583, mixed, and then mixed. Pure water was added to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Particulate powder obtained by spray-drying the slurry with a spray dryer, about 15 g, was charged into an alumina crucible, fired at 1000 ° C. for 12 hours in an air atmosphere (heating rate 5 ° C./min.), Then crushed. The volume resistivity is 9.2 × 10 ⁵ Ω · cm, the carbon concentration is 0.059 wt%, and the composition is Li _1.067 (Li _0.167 Ni _0.254 Mn _0.579 ) O ₂ . Lithium nickel manganese composite oxide (x = 0.167, y = 0, z = 0.067) was obtained. The average primary particle diameter is 0.5 μm, the median diameter is 2.6 μm, the 90% cumulative diameter (D ₉₀ ) is 4.6 μm, the bulk density is 1.0 g / cc, and the BET specific surface area is 2.1 m ² / g. Met.

(Example 3)
Li ₂ CO ₃ , Ni (OH) ₂ , and Mn ₃ O ₄ were weighed and mixed so as to have a molar ratio of Li: Ni: Mn = 1.21: 0.333: 0.556. Pure water was added to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.17 μm using a circulating medium agitation type wet pulverizer.
Particulate powder obtained by spray-drying the slurry with a spray dryer, about 15 g, was charged into an alumina crucible, fired at 900 ° C. for 12 hours in an air atmosphere (heating rate 5 ° C./min.), And then crushed. The volume resistivity is 2.0 × 10 ⁵ Ω · cm, the carbon concentration is 0.084 wt%, and the composition is Li _1.066 (Li _0.111 Ni _0.334 Mn _0.555 ) O ₂ . Lithium nickel manganese composite oxide (x = 0.111, y = 0, z = 0.066) was obtained. Moreover, it confirmed that the crystal structure was comprised including the layered R (-3) m structure. The average primary particle diameter is 0.2 μm, the median diameter is 2.7 μm, the 90% cumulative diameter (D ₉₀ ) is 5.1 μm, the bulk density is 0.8 g / cc, and the BET specific surface area is 3.0 m ² / g. Met.

Example 4
Li ₂ CO ₃ , NiO, Mn ₃ O ₄ were weighed and mixed so that the molar ratio of Li: Ni: Mn = 1.20: 0.50: 0.50 was added, and then pure water was added thereto. A slurry was prepared. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.21 μm using a circulating medium agitation type wet pulverizer.
Particulate powder obtained by spray-drying the slurry with a spray dryer, about 15 g, was charged into an alumina crucible and calcined at 950 ° C. for 12 hours in an air atmosphere (heating rate 5 ° C./min.) And then crushed. And a lithium nickel manganese composite having a volume resistivity of 4.6 × 10 ⁴ Ω · cm, a carbon concentration of 0.050 wt%, and a composition of Li _1.133 (Ni _0.501 Mn _0.499 ) O _2. An oxide (x = 0, y = 0, z = 0.133) was obtained. The average primary particle diameter is 0.6 μm, the median diameter is 3.8 μm, the 90% cumulative diameter (D ₉₀ ) is 6.1 μm, the bulk density is 1.0 g / cc, and the BET specific surface area is 1.9 m ² / g. Met.

(Example 5)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH are weighed so as to have a molar ratio of Li: Ni: Mn: Co = 1.143: 0.278: 0.463: 0.167 After mixing, pure water was added to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.18 μm using a circulating medium agitation type wet pulverizer.
Particulate powder obtained by spray-drying the slurry with a spray dryer, about 15 g, was charged into an alumina crucible, fired at 950 ° C. for 12 hours in an air atmosphere (heating rate 5 ° C./min.), And then crushed. The volume resistivity is 5.0 × 10 ⁵ Ω · cm, the carbon concentration is 0.052% by weight, and the composition is Li _0.986 (Li _0.093 Ni _0.281 Mn _0.458 Co _0.168. ) O ₂ lithium nickel manganese cobalt composite oxide (x = 0.112, y = 0.168, z = −0.014) was obtained. The average primary particle diameter is 0.3 μm, the median diameter is 3.0 μm, the 90% cumulative diameter (D ₉₀ ) is 5.1 μm, the bulk density is 1.0 g / cc, and the BET specific surface area is 2.6 m ² / g. Met.

(Example 6)
Weigh Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , and CoOOH so that the molar ratio of Li: Ni: Mn: Co = 1.10: 0.45: 0.45: 0.10 After mixing, pure water was added to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Particulate powder obtained by spray-drying the slurry with a spray dryer, about 15 g, was charged in an alumina crucible and fired at 925 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.). When pulverized, the volume resistivity is 1.9 × 10 ⁴ Ω · cm, the carbon concentration is 0.043 wt%, and the composition is Li _1.125 (Ni _0.455 Mn _0.445 Co _0.100 ) O. ₂ lithium nickel manganese cobalt composite oxide (x = 0, y = 0.100, z
= 0.125). The average primary particle diameter is 0.2 μm, the median diameter is 1.1 μm, the 90% cumulative diameter (D ₉₀ ) is 1.6 μm, the bulk density is 0.9 g / cc, and the BET specific surface area is 3.3 m ² / g. Met.

(Example 7)
Li ₂ CO ₃ , Ni (OH) ₂ , and Mn ₃ O ₄ were weighed and mixed so as to have a molar ratio of Li: Ni: Mn = 1.15: 0.50: 0.50. Pure water was added to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.14 μm using a circulating medium agitation type wet pulverizer.
Particulate powder obtained by spray-drying the slurry with a spray dryer, about 15 g, was charged into an alumina crucible and fired at 1000 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.). When pulverized, lithium nickel having a volume resistivity of 2.1 × 10 ⁴ Ω · cm, a carbon concentration of 0.045 wt%, and a composition of Li _1.166 (Ni _0.504 Mn _0.496 ) O ₂ Manganese composite oxide (x = 0, y = 0, z = 0.166) was obtained. The average primary particle diameter is 0.5 μm, the median diameter is 3.3 μm, the 90% cumulative diameter (D ₉₀ ) is 5.6 μm, the bulk density is 1.2 g / cc, and the BET specific surface area is 1.9 m ² / g. Met.

(Comparative Example 1)
Ni (OH) ₂ and Mn ₃ O ₄ were weighed and mixed so as to have a molar ratio of Ni: Mn = 0.250: 0.583, and then pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Li ₂ CO ₃ powder having a median diameter of 9 μm was added to and mixed with the particulate powder obtained by spray drying the slurry with a spray dryer. About 100 g of this mixed powder was equally divided into 6 crucibles made of alumina and fired at 950 ° C. for 12 hours under air flow (heating rate 5 ° C./min.) And then crushed to obtain a volume resistivity. Lithium nickel manganese composite oxide (1.4 × 10 ⁶ Ω · cm, carbon concentration is 0.034 wt%, composition is Li _1.035 (Li _0.167 Ni _0.252 Mn _0.581 ) O ₂ ( x = 0.167, y = 0, z = 0.035). The average primary particle diameter is 0.3 μm, the median diameter is 5.7 μm, the 90% cumulative diameter (D ₉₀ ) is 8.6 μm, the bulk density is 1.7 g / cc, and the BET specific surface area is 2.0 m ² / g. Met.

(Comparative Example 2)
Ni (OH) ₂ and Mn ₃ O ₄ were weighed and mixed at a molar ratio of Ni: Mn = 0.333: 0.556, and then mixed with pure water to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.15 μm using a circulating medium agitation type wet pulverizer.
To the particulate powder obtained by spray-drying the slurry with a spray dryer, Li ₂ CO ₃ powder having a median diameter of 9 μm was added and mixed. About 15.9 g of this mixed powder was charged into an alumina crucible, fired at 1000 ° C. for 12 hours under air flow (temperature raising / lowering rate 5 ° C./min.), And then crushed to have a volume resistivity of 9.4 × 10 ⁴ Ω · cm, the concentration of carbon contained is 0.045 wt%, and the composition is Li _1.082 (Li _0.111 Ni _0.335 Mn _0.554 ) O _2, a lithium nickel manganese composite oxide (x = 0. 111, y = 0, z = 0.082). Moreover, it confirmed that the crystal structure was comprised including the layered R (-3) m structure. The average primary particle diameter is 0.4 μm, the median diameter is 5.9 μm, the 90% cumulative diameter (D ₉₀ ) is 8.8 μm, the bulk density is 1.5 g / cc, and the BET specific surface area is 1.1 m ² / g. Met.

(Comparative Example 3)
Ni (OH) ₂ and Mn ₃ O ₄ were weighed and mixed so as to have a molar ratio of Ni: Mn = 0.50: 0.50, and then pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Li ₂ CO ₃ powder having a median diameter of 9 μm was added to and mixed with the particulate powder obtained by spray drying the slurry with a spray dryer. About 87.8 g of this mixed powder was charged equally in 6 pieces of crucible made of alumina, calcined at 1000 ° C. for 12 hours under air flow (heating rate 5 ° C./min.), Crushed, and volume resistance A lithium nickel manganese composite oxide having a rate of 3.9 × 10 ⁴ Ω · cm, a carbon concentration of 0.031 wt%, and a composition of Li _1.084 (Ni _0.505 Mn _0.495 ) O ₂ (x = 0, y = 0, z = 0.084). Moreover, it confirmed that the crystal structure was comprised including the layered R (-3) m structure. The average primary particle diameter is 0.5 μm, the median diameter is 4.7 μm, the 90% cumulative diameter (D ₉₀ ) is 6.9 μm, the bulk density is 1.6 g / cc, and the BET specific surface area is 1.2 m ² / g. Met.

(Comparative Example 4)
Ni (OH) ₂ and Mn ₃ O ₄ were weighed and mixed so as to have a molar ratio of Ni: Mn = 0.50: 0.50, and then pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Li ₂ CO ₃ powder having a median diameter of 9 μm was added to and mixed with the particulate powder obtained by spray drying the slurry with a spray dryer. About 15 g of this mixed powder was put into an alumina crucible, fired at 1000 ° C. for 12 hours under air flow (temperature raising / lowering rate 3.33 ° C./min.), And then crushed to have a volume resistivity of 1.2 ×. 10 ⁴ Ω · cm, carbon concentration is 0.035 wt%, composition of Li _1.152 (Ni _0.505 Mn _0.495 ) O ₂ lithium nickel manganese composite oxide (x = 0, y = 0, z = 0.152) was obtained. The average primary particle diameter is 0.6 μm, the median diameter is 6.1 μm, the 90% cumulative diameter (D ₉₀ ) is 9.1 μm, the bulk density is 1.5 g / cc, and the BET specific surface area is 0.7 m ² / g. Met.

(Comparative Example 5)
Ni (OH) ₂ , Mn ₃ O ₄ , and CoOOH were weighed and mixed so as to have a molar ratio of Ni: Mn: Co = 0.278: 0.463: 0.167, and then pure water was added thereto. In addition, a slurry was prepared. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.

Li ₂ CO ₃ powder having a median diameter of 9 μm was added to and mixed with the particulate powder obtained by spray drying the slurry with a spray dryer. About 15.4 g of this mixed powder was charged into an alumina crucible, fired at 900 ° C. for 12 hours under air flow (heating temperature increase / decrease rate of 5 ° C./min.), And then crushed to have a volume resistivity of 1.1 ×. 10 ⁶ Ω · cm, carbon concentration is 0.046 wt%, and the composition is Li _0.960 (Ni _0.280 Mn _0.459 Co _0.168 ) O ₂ lithium nickel manganese cobalt composite oxide (x = 0) .112, y = 0.168, z = −0.040). The average primary particle diameter is 0.2 μm, the median diameter is 5.2 μm, the 90% cumulative diameter (D ₉₀ ) is 7.7 μm, the bulk density is 1.8 g / cc, and the BET specific surface area is 2.2 m ² / g. Met.

(Comparative Example 6)
Ni (OH) ₂ , Mn ₃ O ₄ , and Co (OH) ₂ were weighed and mixed so as to have a molar ratio of Ni: Mn: Co = 0.45: 0.45: 0.10. Pure water was added to the slurry to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.15 μm using a circulating medium agitation type wet pulverizer.
LiOH powder pulverized to a median diameter of 20 μm or less was added to and mixed with the particulate powder obtained by spray drying the slurry with a spray dryer. About 13.1 g of this mixed powder was charged into an alumina crucible and fired at 950 ° C. for 10 hours under air flow (heating rate 5 ° C./mi
n. The volume resistivity is 1.7 × 10 ⁴ Ω · cm, the carbon concentration is 0.031 wt%, and the composition is Li _1.130 (Ni _0.443 Mn _0.453 Co _{0 .105} ) O ₂ lithium nickel manganese cobalt composite oxide (x = 0, y = 0.105, z = 0.130) was obtained. The average primary particle size is 0.5 μm, the median diameter is 11.1 μm, the 90% cumulative diameter (D ₉₀ ) is 18.4 μm, the bulk density is 1.8 g / cc, and the BET specific surface area is 1.3 m ² / g. Met.

  Tables 1 and 2 show the compositions and physical property values of the lithium transition metal-based compound powders (positive electrode materials) produced in Examples and Comparative Examples.

[Production and evaluation of batteries]
Using the lithium nickel manganese cobalt composite oxide powders produced in Examples 1 to 5 and Comparative Examples 1 to 5 described above as positive electrode materials (positive electrode active materials), lithium secondary batteries were produced by the following method. And evaluated.
Rate test:
75% by weight of each of the lithium nickel manganese cobalt composite oxide powders produced in Examples 1 to 5 and Comparative Examples 1 to 5, 20% by weight of acetylene black, and 5% by weight of polytetrafluoroethylene powder were weighed. The material was mixed thoroughly in a mortar, and a thin sheet was punched out using a 9 mmφ punch. At this time, the total weight was adjusted to about 8 mg. This was pressure-bonded to an aluminum expanded metal to obtain a 9 mmφ positive electrode.

An electrolytic solution in which LiPF ₆ is dissolved at a concentration of 1 mol / L in a solvent of EC (ethylene carbonate): EMC (ethyl methyl carbonate) = 3: 7 (volume ratio) using the 9 mmφ positive electrode as a test electrode and a lithium metal plate as a counter electrode. A coin-type cell was assembled using a porous polyethylene film having a thickness of 25 μm as a separator.
With respect to the obtained coin-type cell, in the initial two cycles, the charging upper limit voltage was set to 4.8 V, and constant current / constant voltage charging (current density: up to 4.8 V at 0.137 mA / cm ² (0.1 C)) After constant current charge, constant voltage charge until 0.01C is achieved, and then the discharge lower limit voltage is set to 3.0 V and constant current discharge (current density 0.137 mA / cm 2 (0.1 C)) is performed. It was. Subsequently, in the third cycle, constant current / constant voltage charging with a constant current of 0.1 C and a charging upper limit voltage set to 4.4 V (current density: up to 4.4 V at 0.137 mA / cm 2 (0.1 C)) After constant current charge, constant voltage charge until 0.01C), a charge / discharge 1 cycle test was conducted by constant current discharge with the discharge lower limit voltage set to 3.0 V, and the 4th to 11th cycles were further reduced to 0. 2C constant current / constant voltage charging (constant current charging to 4.4V at 0.2C, then constant voltage charging to 0.01C), 0.1C, 0.2C, 0.5C, 1C, 3C, 5C , 7C, and 9C were tested with constant current discharge. However, the current corresponding to 1 C was assumed to be 150 mA per 1 g of active material. 0.1C discharge capacity (mAh / g) at the first cycle (initial discharge capacity) at this time, 0.1C discharge capacity (mAh / g) at the fourth cycle (discharge capacity at the fourth cycle) [a]), 7 1C discharge capacity (mAh / g) at the cycle (7th cycle discharge capacity [b]), and the percentage (%) of the 7th cycle discharge capacity [b] with respect to the 4th cycle discharge capacity [a], The 9C discharge capacity (mAh / g) was examined, and the results are shown in Table 3.

  In addition, as an acceptance criterion of the examples, the initial discharge capacity in the first cycle is 200 mAh / g or more, the 1C discharge capacity in the seventh cycle is 150 mAh / g or more, and the percentage of the 1C discharge capacity with respect to the 0.1 C discharge capacity. (%) Was set to 82% or more, and the 9C discharge capacity at the 11th cycle was set to 60 mAh / g or more.

Furthermore, using the lithium nickel manganese cobalt composite oxide powders manufactured in Examples 6 and 7 and Comparative Example 6 described above as positive electrode materials (positive electrode active materials), lithium secondary batteries were produced by the following method. And evaluated.
Rate test:
75% by weight of each of the lithium nickel manganese cobalt composite oxide powders prepared in Examples 6 and 7 and Comparative Examples 4 and 6, 20% by weight of acetylene black, and 5% by weight of polytetrafluoroethylene powder were weighed. The product was mixed well in a mortar, and a thin sheet was punched out using a 9 mmφ punch. At this time, the total weight was adjusted to about 8 mg. This was pressure-bonded to an aluminum expanded metal to obtain a 9 mmφ positive electrode.
This 9 mmφ positive electrode is used as a test electrode, a lithium metal plate is used as a counter electrode, and LiPF ₆ is added to a solvent of EC (ethylene carbonate): DMC (dimethyl carbonate): EMC (ethyl methyl carbonate) = 3: 3: 4 (volume ratio). Using an electrolytic solution dissolved at 1 mol / L, a coin-type cell was assembled using a porous polyethylene film having a thickness of 25 μm as a separator.
For the obtained coin-type cell, in the initial two cycles, the charging upper limit voltage was set to 4.4 V, and constant current / constant voltage charging (current density: up to 4.4 V at 0.137 mA / cm ² (0.1 C)) After constant current charging, constant voltage charging was performed until 0.01 C was reached, and then the discharge lower limit voltage was set to 3.0 V, and constant current discharging (current density 0.137 mA / cm ² (0.1 C)) was performed. went. Furthermore, in the 3rd to 10th cycles, 0.2C constant current / constant voltage charging (constant current charging up to 4.4V at 0.2C and then constant voltage charging to 0.01C), 0.1C, 0.2C , 0.5C, 1C, 3C, 5C, 7C, and 9C constant current discharges were tested. However, the current corresponding to 1 C was assumed to be 150 mA per 1 g of active material. 0.1C discharge capacity (mAh / g) at the first cycle (initial discharge capacity) at this time, 0.1C discharge capacity (mAh / g) at the third cycle (discharge capacity at the third cycle) [a]), 6 1C discharge capacity (mAh / g) at the cycle (6th cycle discharge capacity [b]) and 9C discharge capacity (mAh / g) at the 10th cycle) (discharge capacity [c] at the 10th cycle) Are shown in Table 4.
In addition, as an acceptance criterion of the examples, the initial discharge capacity in the first cycle is 170 mAh / g or more, the 0.1C discharge capacity in the third cycle is 175 mAh / g or more, and the 1C discharge capacity in the sixth cycle is 155 mAh / g. As described above, the 9C discharge capacity at the 10th cycle was set to 110 mAh / g or more.

From Table 3, the following is clear.
In Comparative Examples 1 to 4, since the mercury intrusion amount is too small, the discharge capacity of the battery is low for both the low rate and the high rate.
In Comparative Example 5, in addition to the amount of mercury intrusion being too small, the Li amount z is less than the lower limit, so the discharge capacity of the battery is low for both low rate and high rate.
The following is clear from Table 4.
In Comparative Examples 4 and 6, since the amount of mercury intrusion is too small, the discharge capacity of the battery is low for both the low rate and the high rate as compared with the example samples (Examples 7 and 6) having substantially the same Co molar ratio (y).

In contrast, by using the lithium transition metal compound powder of the present invention having a specific amount of mercury intrusion as a positive electrode material, cycle deterioration during high voltage use can be suppressed, capacity is high, and load characteristics are excellent. It can be seen that a positive electrode material for a lithium secondary battery having a good performance balance is provided.
Table 5 shows the powder properties (median diameter, bulk density, specific surface area) of the spray-dried bodies (fired precursors) in Examples 1 to 5 and Comparative Examples 1 to 5.

From Table 5, Examples 1-5 have a median diameter after ultrasonic dispersion (5 minutes) of 0.1 μm or more and 1 μm or less, and a BET specific surface area of 10-60 m ² / g, whereas Comparative Examples 1-5. It is clear that 5 is greater than 1 μm (all greater than 5 μm) and greater than 60 m ² / g.

  The use of the lithium secondary battery of the present invention is not particularly limited, and can be used for various known uses. Specific examples include notebook computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, and transceivers. Electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, lighting equipment, toys, game machines, watches, strobes, cameras, power tools, automotive power sources, and the like.

In Example 1, it is a graph which shows the pore distribution curve of the manufactured lithium nickel manganese complex oxide powder. In Example 2, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese complex oxide. In Example 3, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese complex oxide. In Example 4, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese complex oxide. In Example 5, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese cobalt complex oxide. In Comparative example 1, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese complex oxide. In Comparative Example 2, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese complex oxide. In Comparative example 3, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese complex oxide. In Comparative example 4, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese complex oxide. In Comparative Example 5, it is a graph showing the pore distribution curve of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 1, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese complex oxide. In Example 2, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese composite oxide. In Example 3, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese composite oxide. In Example 4, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese composite oxide. In Example 5, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide. In Comparative example 1, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese complex oxide. In Comparative example 2, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese complex oxide. In Comparative example 3, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese complex oxide. In Comparative example 4, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese complex oxide. In Comparative example 5, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt complex oxide. In Example 1, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In Example 2, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In Example 3, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In Example 4, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In Example 5, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide manufactured. In Comparative example 1, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In comparative example 2, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In Comparative example 3, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In Comparative Example 4, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In Comparative example 5, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese cobalt complex oxide. In Example 6, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 7, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese complex oxide. In Comparative example 6, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese cobalt complex oxide. In Example 6, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide. In Example 7, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese composite oxide. In Comparative example 6, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide. In Example 6, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide manufactured. In Example 7, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese complex oxide. In the comparative example 6, it is a graph which shows the XRD pattern of the manufactured lithium nickel manganese cobalt complex oxide.

Claims (12)

In mercury intrusion curve obtained by mercury intrusion porosimetry, mercury penetration amount at boosting the pressure 3.86kPa to 413MPa is, 0.8 cm ³ / g or more, ^{3 cm} 3 / g Ri der below, a bulk density of 0.5 to 1 .5g / cm ³ der Rukoto lithium secondary and wherein the battery positive electrode material for a lithium transition metal based compound powder.   The pore distribution curve by the mercury intrusion method has a main peak having a peak top at a pore radius of 300 nm or more and 1000 nm or less, and has no sub-peak having a peak top at a pore radius of 80 nm or more and less than 300 nm. The lithium transition metal-based compound powder according to claim 1. In the pore distribution curve by the mercury intrusion method, the pore volume related to the main peak having a peak top at a pore radius of 300 nm or more and 1000 nm or less is 0.5 cm ³ / g or more and 1.5 cm ³ / g or less. The lithium transition metal-based compound powder according to claim 1 or 2.   The median diameter measured after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz) using a laser diffraction / scattering particle size distribution analyzer with a refractive index of 1.24 and a particle size standard as a volume standard. The lithium transition metal-based compound powder according to any one of claims 1 to 3, wherein is 0.6 to 5 µm. The lithium transition metal-based compound powder according to any one of claims 1 to 4, which is a lithium nickel manganese cobalt-based composite oxide represented by the following composition formula (I). Li [Li _{z / (2 + z)} {(Li _x Ni _{(1-3x) / 2} Mn _{(1 + x) / 2} ) _1-y Co _y } _{2 / (2 + z)} ] O _2. (I)
(However, 0 ≦ x ≦ 0.33
0 ≦ y ≦ 0.2
−0.02 ≦ z ≦ 0.2 (1-y) (1-3x)) The lithium transition metal-based compound powder according to any one of claims 1 to 5, wherein a bulk density is 0.5 to 1.5 g / cm ³ . BET specific surface area is 1.5-5 m < ² > / g, The lithium transition metal type compound powder of any one of Claim 1 thru | or 6 characterized by the above-mentioned.   The lithium according to any one of claims 1 to 7, wherein the C value is 0.005 wt% or more and 0.2 wt% or less when the carbon content is C (wt%). Transition metal compound powder.   A spray-dried body obtained by pulverizing a lithium compound and at least one or more transition metal compounds in a liquid medium and spray-drying a slurry in which these are uniformly dispersed is fired in an oxygen-containing gas atmosphere. The method for producing a lithium transition metal-based compound powder according to any one of claims 1 to 8. The production method according to claim 9, wherein the lithium compound is lithium carbonate.   9. A lithium secondary battery comprising a positive electrode active material layer containing the lithium transition metal-based compound powder according to claim 1 and a binder on a current collector. Positive electrode. A lithium secondary battery comprising a negative electrode capable of inserting and extracting lithium, a nonaqueous electrolyte containing a lithium salt, and a positive electrode capable of inserting and extracting lithium, wherein the lithium secondary battery according to claim 11 is used as the positive electrode. A lithium secondary battery using a positive electrode for a battery.