JP5687169B2 - Positive electrode active material for lithium secondary battery, method for producing the same, and lithium secondary battery - Google Patents

Description

  The present invention relates to a positive electrode active material powder for a lithium secondary battery, a production method thereof, and a lithium secondary battery.

In recent years, electronic devices have become rapidly portable and cordless. In addition, electric vehicles have been actively developed to solve environmental and energy problems.
Accordingly, lithium secondary batteries having high voltage and high energy density are attracting attention as power sources for driving electronic devices.

As one means for obtaining a high energy density lithium secondary battery, a solid solution positive electrode has been studied.
For example, Patent Document 1 below proposes using a solid solution of LiNiO ₂ and Li ₂ MnO ₃ as the positive electrode active material.

  However, although the lithium secondary battery using the solid solution of Patent Document 1 has a large discharge capacity, when it is used with a high charge / discharge potential, the cycle characteristics are poor and the battery is easily deteriorated by repeated charge / discharge. is there.

In addition, a method in which the solid solution is subjected to oxidation treatment as a positive electrode active material (see, for example, Patent Document 2 and Patent Document 3), or a general formula: xLi ₂ MO _3. (1-x) Li [Ni _{1-y -Z} Co _y A _z ] O ₂ (x is a number satisfying 0.4 ≦ x ≦ 1.0, M is one or more elements selected from the group consisting of Mn, Ti and Zr; A is one or more elements selected from the group consisting of B, Al, Ga and In, and 0 <y ≦ 0.3 and 0 <z ≦ 0.1.) A method for use as an active material has been proposed, but a high capacity and further improved cycle characteristics are desired.

Japanese Patent Application Laid-Open No. 09-55211 JP 2008-270201 A JP 2010-108873 A

  Accordingly, an object of the present invention is a positive electrode active material powder for a lithium secondary battery that has a high capacity, suppresses deterioration due to charge / discharge at a high potential, and can be a lithium secondary battery excellent in cycle characteristics, and It is an object of the present invention to provide a production method and a lithium secondary battery having high cycle capacity and excellent cycle characteristics using the same.

As a result of intensive studies in view of the above circumstances, the present inventors have determined that the lithium nickel composite oxide represented by the general formula (1) having a specific range of colors in the L ^* a ^* b ^* color system. The product imparts to the lithium secondary battery excellent battery performance as a positive electrode active material, specifically, high capacity, low battery charge / discharge deterioration, and excellent cycle characteristics. As a result, the present invention has been completed.

That is, the present invention (1) has the following general formula:
_{xLi 2 MO 3 · (1-} x) Li [Ni 1-y-z M y Me z] O 2 (1)
(In the formula, M represents a metal element selected from Mn, Ti and Zr. Me represents an element having an atomic number of 11 or more other than Mn, Ti, Zr and Ni . X represents 0.4 ≦ x ≦ 0. 6 and y are 0 ≦ y ≦ 0.6, and z is 0 ≦ z ≦ 0.1.), And L in the L ^* a ^* b ^* color system, ^* value from 15.0 to 25.0, a value ^* is 1.00-15.0, ^{b *} value Ri der -5.0～5.0, average particle diameter determined from the particle size distribution measurement ( D ₅₀ ) is 1 μm or more and 30 μm or less, 10% cumulative diameter (D ₁₀ ) is 1 μm or more and 10 μm or less, 90% cumulative diameter (D ₉₀ ) is 15 μm or more and 50 μm or less, and the relative frequency in the particle size of D ₅₀ is 10 % Or less of the positive electrode active material powder for a lithium secondary battery.

The present invention (2) has the following general formula:
_{xLi 2 MO 3 · (1-} x) Li [Ni 1-y-z M y Me z] O 2 (1)
(In the formula, M represents a metal element selected from Mn, Ti and Zr. Me represents an element having an atomic number of 11 or more other than Mn, Ti, Zr and Ni . X represents 0.4 ≦ x ≦ 0. 6 and y are 0 <y ≦ 0.6, and z is 0 ≦ z ≦ 0.1.) A method for producing a positive electrode active material for a lithium secondary battery comprising a lithium nickel composite oxide. And
A slurry containing a nickel source and an M source, or a nickel source, an M source and a Me source and having an average solid content of 0.1 to 2.0 μm in a spray drying apparatus equipped with a four-fluid nozzle, A spray-drying step in which the feed rate is 50 to 150 kg / hour and the pressure of the spray gas is 0.1 MPa or more to obtain a spray-dried product by spray-drying, and then the spray-dried product and the lithium source are mixed. A firing raw material mixing step for obtaining a firing raw material mixture;
A firing step of firing the firing raw material mixture to obtain a positive electrode active material powder for a lithium secondary battery comprising the lithium nickel-based composite oxide represented by the general formula (1);
Have a, the spray-dried product with an average particle diameter determined from the particle size distribution measurement value _{(D 50)} is 1.0μm or more 30.0μm or less, 10% cumulative diameter _{(D 10)} is 1.0μm or more 10.0μm In the following, lithium _{90 having} a 90% cumulative diameter (D ₉₀ ) of not less than 15.0 μm and not more than 50.0 μm and a relative frequency in the particle size of D ₅₀ adjusted to 10.0% or less. The manufacturing method of the positive electrode active material powder for secondary batteries is provided.

  In addition, the present invention (3) provides a lithium secondary battery obtained by using the positive electrode active material powder for a lithium secondary battery according to the present invention (1) as a positive electrode active material. It is.

  According to the positive electrode active material powder for a lithium secondary battery of the present invention, it is possible to provide a lithium secondary battery having a high capacity, suppressing deterioration due to charge / discharge at a high potential, and having excellent cycle characteristics.

Schematic diagram of a four fluid nozzle device. Schematic of a spray drying apparatus equipped with a four-fluid nozzle. 2 is a particle size distribution diagram of the spray-dried product obtained in Example 1. FIG. 4 is a particle size distribution diagram of the spray-dried product obtained in Comparative Example 1. FIG. 2 is a particle size distribution diagram of the lithium nickel composite oxide obtained in Example 1. FIG. 2 is a particle size distribution diagram of the lithium nickel composite oxide obtained in Example 1. FIG. 2 is an X-ray diffraction diagram of the lithium nickel composite oxide obtained in Example 1. FIG.

The positive electrode active material powder for a lithium secondary battery of the present invention has the following general formula (1):
_{xLi 2 MO 3 · (1-} x) Li [Ni 1-y-z M y Me z] O 2 (1)
(In the formula, M represents a metal element selected from Mn, Ti and Zr. Me represents Mn, Ti, Zr and other elements having an atomic number of 11 or more. X represents 0.4 ≦ x ≦ 0.6. , Y is 0 ≦ y ≦ 0.6, and z is 0 ≦ z ≦ 0.1.), L ^* a ^* b ^* L ^* in the color system value from 15.0 to 25.0, a value ^* is 1.00 to 15.0, ^{b *} values Ri der -5.0～5.0, average particle size (D determined from the particle size distribution measurement value ₅₀ ) is from 1 μm to 30 μm, the 10% cumulative diameter (D ₁₀ ) is from 1 μm to 10 μm, the 90% cumulative diameter (D ₉₀ ) is from 15 μm to 50 μm, and the relative frequency in the particle size of D ₅₀ is 10%. It is as follows .

M in the general formula (1) represents a metal element selected from Mn, Ti and Zr, and among these, Mn is particularly preferable from the viewpoint of obtaining a high discharge capacity.
Further, Me in the general formula (1) is an element added as necessary, and is an element having an atomic number of 11 or more other than Mn, Ti, Zr and Ni. Preferable examples of the Me element include Ca, Mg, Al, Si, P, V, Cr, Fe, Co, Cu, Zn, Nb, Mo, Ag, and Sr. Or 2 or more types may be sufficient.

The x in the general formula (1), preferably 0.4 ≦ x ≦ 0.6, y is, 0 ≦ y ≦ 0.6, preferably 0.4 ≦ y ≦ 0.6, also , Z is 0 ≦ z ≦ 0.1, preferably 0 ≦ z ≦ 0.08.

The positive electrode active material powder for a lithium secondary battery of the present invention has been used as a conventional positive electrode active material powder for a lithium secondary battery among the lithium nickel-based composite oxides represented by the general formula (1). The object color is different from the one. That is, the L ^* value in the L ^* a ^* b ^* color system of the positive electrode active material powder for a lithium secondary battery of the present invention is 15.0 to 25.0, preferably 18.0 to 22.0. The a value ^* is 1.00 to 15.0, preferably 5.0 to 10.0, and the b ^* value is −5.0 to 5.0, preferably 0 to 5.0. The L ^* a ^* b ^* color system of the positive electrode active material powder for a lithium secondary battery according to the present invention has an L ^* value, a ^* value, and b ^* value in the above ranges, which is excellent for a lithium secondary battery. Since battery performance can be imparted, it is possible to obtain a lithium secondary battery having high capacity and excellent cycle characteristics in which deterioration due to charge / discharge at a high potential is suppressed.

On the other hand, the conventional formula (1) positive electrode active material powder for a lithium secondary battery comprising a lithium-nickel-based composite oxide represented by the, L ^* a ^* b ^* in the color system, L ^* value is 22. 0 to 30.0, a value ^* is in the range of 0 to 5.0, and b ^* value is in the range of 0 to -10.0. As far as the present inventors know, in the L ^* a ^* b ^* color system None of the L ^* value, a value ^*, and b ^* value ranges within the scope of the present invention are satisfied.

In the present ^invention, in the L ^* a * ^{b *} color system, ^{L *} value, a value ^* and ^{b *} values are the color difference measured by a color difference meter, it is defined in Japanese Industrial Standard JIS Z 8730 Yes.
The L ^* value in the L ^* a ^* b ^* color system represents lightness ^{. The} higher the value, the whiter the color, the 100 becomes perfect white, the smaller the value, the black, and 0 the complete black. The a value and the b value represent hues, and the larger the a value, the deeper the red color, the smaller the a value, the darker the green color, the larger the b value, the darker the yellow color, and the smaller the b value, the blue color. It becomes darker.

  The positive electrode active material for a lithium secondary battery of the present invention is a powder, and the color difference measurement of the powder is performed by a method of slurrying a powder sample, a method of pelletizing, and a method of filling a dedicated petri dish However, in the positive electrode active material for a lithium secondary battery of the present invention, a method of filling a petri dish and measuring is preferable. This is a method of slurrying a positive electrode active material for a lithium secondary battery, because it causes a change in composition due to Li desorption in the slurry and causes a color change. This is because it is not preferable because color change occurs due to reflection on the pellet surface or pressurization.

The positive electrode active material powder for a lithium secondary battery of the present invention comprises secondary particles formed by agglomerating primary particles of the lithium nickel composite oxide represented by the general formula (1), and the secondary particles It contains primary particles that are broken or cannot be aggregated. The positive electrode active material for a lithium secondary battery according to the present invention has an average particle size determined from a laser diffraction / scattering method of 1 μm or more and 30 μm or less and a particle size of 1.0 μm or more and 5.0 μm or less, Coarse particles having a larger particle size than the fine particles are included in a specific range.
That is, the particle size distribution of the positive electrode active material powder for a lithium secondary battery of the present invention has an average particle size (D ₅₀ ) of 1 μm or more and 30 μm or less, preferably 5 in the measured particle size distribution obtained from the laser diffraction / scattering method. 1.0 μm to 25.0 μm, 10% cumulative diameter (D ₁₀ ) of 1 μm to 10 μm, preferably 1.0 μm to 8.0 μm, 90% cumulative diameter (D ₉₀ ) of 15 μm to 50 μm, preferably and at 15μm or 30μm or less, and less relative frequency of 10% in the particle size of _{D 50,} preferably 8% or less than 2%. The positive electrode active material powder for a lithium secondary battery of the present invention has a particle size distribution in the above range, thereby improving the electrode density of the lithium secondary battery and further improving the discharge capacity.
In the present invention, although the particle size distribution of the positive electrode active material powder for the lithium secondary battery is in the above range, it is not clear why the performance of the lithium secondary battery such as electrode density can be further improved. The present inventors presume that small particles enter the gaps between the large particles to improve the filling property.

  The particle size distribution of the positive electrode active material powder for a lithium secondary battery is 1 with a laser diffraction / scattering method (measuring device: manufactured by Nikkiso Co., Ltd., Microtrac MT3300EXII particle size analyzer, MTEX-SDU, dispersion medium: water, ultrasonic homogenizer). It is a volume frequency particle size distribution measured by minute pretreatment. In the frequency particle size distribution measurement, the region between 2000 μm and 0.023 μm is divided into 132 channel particle size distribution bands, the particle distribution is obtained, and the intermediate value of each distribution band is determined as the particle size “D (μm ) ”, And the percentage of the volume of the particles in each distribution band with respect to the total volume of the particles is defined as the frequency value“ P (%) ”of the particles having the particle diameter D (μm).

  The average particle size of the primary particles of the positive electrode active material powder for a lithium secondary battery of the present invention is an average particle size determined by observation with a scanning electron micrograph (SEM), preferably 0.1 to 10.0 μm. Is preferably 0.1 to 5.0 μm from the viewpoint of obtaining a high discharge capacity.

Moreover, the tap density of the positive electrode active material powder for a lithium secondary battery of the present invention is 0.5 g / cm ³ or more, preferably 0.5 to 2.5 g / cm ³ , so that the electrode density is high. From the viewpoint of

The tap density in the present invention is based on the method of apparent density or apparent specific volume described in JIS-K-5101, and 5 g of sample is put into a 5 ml graduated cylinder by the tap method and tapped 500 times. After standing, read the volume, the following formula:
Tap density (g / ml) = F / V
(Where F represents the mass (g) of the processed sample in the receiver, and V represents the volume (ml) of the sample after tapping.).

Moreover, the BET specific surface area of the positive electrode active material powder for lithium secondary batteries of this invention is 0.5-3.0 m < ² > / g, Preferably it is 1.0-3.0 m < ² > / g. When the BET specific surface area of the positive electrode active material powder for a lithium secondary battery is in the above range, the safety of the lithium secondary battery is increased.

  The amount of lithium carbonate remaining in the positive electrode active material powder for a lithium secondary battery is 0.5% by mass or less, preferably 0.4% by mass or less. Further, the amount of lithium hydroxide remaining in the positive electrode active material powder for a lithium secondary battery is 0.5% by mass or less, preferably 0.4% by mass or less. When the amount of lithium carbonate and lithium hydroxide remaining in the positive electrode active material powder for a lithium secondary battery is in the above range, swelling of the lithium secondary battery can be suppressed, and safety can be improved.

The positive electrode active material powder for a lithium secondary battery of the present invention contains (1) a nickel source and an M source, or (2) a nickel source, an M source and a Me source, and has an average particle size of 0.1% in solid content. A spray-dried product obtained by spray-drying a slurry of up to 2.0 μm in a spray-drying apparatus equipped with a four-fluid nozzle at a slurry supply rate of 50-150 kg / hour and a spray gas pressure of 0.1 MPa or more. A spray-drying step for obtaining a firing raw material mixture step, wherein the spray-dried product and a lithium source are mixed to obtain a firing raw material mixture;
A firing step of firing the firing raw material mixture to obtain a positive electrode active material powder for a lithium secondary battery comprising the lithium nickel-based composite oxide represented by the general formula (1);
It is manufactured by performing the manufacturing method of the positive electrode active material powder for lithium secondary batteries characterized by having.

  The spray drying step according to the positive electrode active material powder for a lithium secondary battery of the present invention includes (1) nickel source and M source, or (2) slurry containing nickel source, M source and Me source by spray drying. This is a step of obtaining a spray-dried product.

  In the spray drying step, the slurry to be spray dried is a slurry containing (1) a nickel source and an M source or (2) a nickel source, an M source and a Me source.

The nickel source in the spray drying process is not particularly limited. For example, nickel hydroxide or oxide such as Ni (OH) ₂ , NiO, NiOOH; NiCO ₃ .6H ₂ O, Ni (NO ₃ ) ₂ Inorganic salts of nickel such as 6H ₂ O, NiSO ₄ , NiSO ₄ .6H ₂ O, NiC ₂ O ₄ .2H ₂ O; and organic nickel compounds such as fatty acid nickel. Among these, as the nickel source, Ni (OH) ₂ is preferable from the viewpoint that it can be obtained as an industrial raw material at a low cost and the reactivity is high. Of course, a plurality of types of nickel sources may be used. The nickel source in the spray drying process is preferably a compound that is hardly soluble in the dispersion medium.

  The M source according to the spray drying process is a compound having an M element. The M element is one or more metal elements selected from Mn, Ti and Zr, and the M source is an oxide, hydroxide, oxyhydroxide, carbonate, nitrate, sulfate of the M element. And organic acid salts.

  In the spray drying process, the slurry to be spray-dried is a nickel source, if necessary, for the purpose of further improving the performance of the lithium secondary battery, such as battery safety, discharge capacity, and rapid charge / discharge. The aforementioned Me source other than the M source can be contained. The Me source is a compound containing the Me element, and preferable examples of the Me element include, for example, Ca, Mg, Al, Si, P, V, Cr, Fe, Co, Cu, Zn, Nb, Mo, Ag, and One or two or more selected from Sr and the like, and examples of the Me source include Me element oxides, hydroxides, oxyhydroxides, carbonates, nitrates, sulfates, and organic acid salts.

  In this production method, the nickel source, the M source, the Me source, and the lithium source described later are preferably those having as little impurity content as possible in order to produce a high-purity positive electrode active material.

  In the spray-drying step, in the slurry to be spray-dried, a nickel source, an M source, and a Me source used as necessary are dispersed in a dispersion medium. Examples of the dispersion medium include water and an aqueous solution in which a water-soluble organic solvent is blended with water.

  In the spray-drying process, the content ratio of the nickel source and the M source in the slurry to be spray-dried, and the content ratio of the Me element used as necessary, what composition ratio of the lithium nickel-based composite oxide is produced? However, the ratio (Ni / A) of the number of moles of nickel in terms of atoms to the total number of moles (A) in terms of atoms of nickel, M element, and Me element is preferably 0.1-0. 5, particularly preferably 0.1 to 0.3, and the ratio of the number of moles in terms of atoms of M element to the total number of moles in terms of atoms of nickel, M element and Me element (A) (M / A) Is preferably 0.5 to 0.9, particularly preferably 0.6 to 0.9. When the slurry contains a compound having the Me element, the ratio of the number of moles of the Me element in terms of atoms to the total number of moles (A) of the nickel, M element, and Me element (Me / A) is preferably 0. More than 0.4, particularly preferably more than 0 and 0.3 or less. When the slurry does not contain Me element, the total number of moles (A) is the total number of moles in terms of atoms of nickel and M element, and when the slurry contains two or more types of Me element, Me The number of moles of elements in terms of atoms is the total number of moles of moles in terms of atoms of each Me element.

  In the spray drying step, the solid content concentration of the slurry to be spray dried is a mass ratio of the solid content to the whole slurry, preferably 10.0 to 50.0% by mass, particularly preferably 15.0 to 50.0% by mass. More preferably, the content is 20.0 to 50.0% by mass from the viewpoint of improving productivity.

  In the spray-drying step, the slurry to be spray-dried may further contain additives such as a dispersant such as Poise 2100 (manufactured by Kao Corporation) and San Nopco 5468 (manufactured by San Nopco).

  In the spray drying step, the average particle size of the solid content in the slurry to be spray dried is 0.1 to 2.0 μm, preferably 0.1 to 1.6 μm. When the average particle size of the solid content in the slurry is in the above range, the discharge capacity of the lithium secondary battery is increased. The reason why the average particle size of the solid content in the slurry is within the above range is that if the average particle size of the solid content in the slurry is less than 0.1 μm, the slurry viscosity becomes high and spray spraying becomes difficult. Further, when the average particle size of the solid content in the slurry is larger than 2.0 μm, the primary particles are large and a sufficient charge / discharge capacity cannot be obtained.

  The slurry to be spray-dried is obtained by wet-grinding a nickel source, an M source, and an Me source used as necessary in a dispersion medium. In this wet pulverization, the wet pulverization is performed until the average particle size of the solid content in the slurry obtained by the laser diffraction / scattering method becomes 0.1 to 2 μm, preferably 0.1 to 1.6 μm. In the wet pulverization, the average particle size of the solid content in the slurry can be controlled by appropriately selecting the wet pulverization conditions.

  As an apparatus for performing wet pulverization, it is preferable to use a media mill from the viewpoint of controlling the average particle size of the solid content in the slurry to be in the above range. As the media mill, a bead mill, a ball mill, a paint shaker, Examples include attritors and sand mills.

  For example, when wet pulverization is performed using a bead mill, the wet pulverization conditions such as solid content concentration, presence / absence and use of a dispersant, bead particle size, mill frequency, number of wet pulverization treatments, input speed, etc. are appropriately selected. Thus, the average particle size of the solid content in the slurry obtained by wet pulverization, that is, the slurry to be spray-dried is adjusted.

  In the spray drying step, a spray-dried product is obtained by spray-drying the slurry adjusted so that the solid content has a predetermined particle property.

  In the spray drying process, in the present invention, the raw material mixed slurry is performed by a spray drying apparatus equipped with a four-fluid nozzle.

  There are known methods for drying the slurry other than a method using a spray drying apparatus equipped with a four-fluid nozzle, but it is advantageous to use a spray drying apparatus equipped with a four-fluid nozzle in this production method. Based on the knowledge, this drying method is adopted. Specifically, when a spray drying apparatus equipped with a four-fluid nozzle is used, finer particles of solid material particles can be obtained compared to other spray drying methods. Moreover, the obtained spray-dried product can be easily obtained with a particle size distribution described later by appropriately selecting the spray-drying conditions.

The four-fluid nozzle is a device that causes a gas to collide with a mixture of a raw material and a liquid at the tip of the nozzle to make it into a mist. FIG. 1 shows a schematic diagram of an embodiment of a four-fluid nozzle. The schematic diagram of one Embodiment of the spray-drying apparatus provided with the 4 fluid nozzle in FIG. 2 is shown.
The spray drying apparatus provided with a four-fluid nozzle used in this manufacturing method basically includes a four-fluid nozzle (1) and a drying chamber (7). The spray drying apparatus equipped with a four-fluid nozzle has two liquid flow paths (2a, 2b) and two gas flow paths (3a, 3b) in the nozzle (1), and compressed air (4 ) Causes the spray liquid (5) to be thinly stretched at the fluid flow surface (6) to produce droplets (8) atomized by the strong shock wave generated at the focal point (4a) at the edge of the four-fluid nozzle, and hot air is introduced inside. This is a device for obtaining fine particles (9) by bringing droplets (8) into contact with hot air in a drying chamber (7) that can be supplied and drying instantaneously.
In addition, the spray-drying apparatus provided with the 4-fluid nozzle is already well-known (For example, Unexamined-Japanese-Patent No. 08-281155 gazette, an industrial research group issue "Chemical apparatus" June, 2000, pp. 60-65, an industrial research group publication. “Chemical equipment”, June 2002, pages 85 to 90, etc.) and is commercially available.
1 and 2, a straight edge type is shown as the four-fluid nozzle, but a circle edge type can also be used in the same manner.

In the spray drying step, the average particle size (D ₅₀ ) is 1 μm or more and 30 μm or less, preferably 1.0 μm or more and 20.0 μm in the particle size distribution measurement value obtained from the laser diffraction / scattering method for the spray dried product obtained by spray drying. In the following, the 10% cumulative diameter (D ₁₀ ) is 1 μm to 10 μm, preferably 5.0 μm to 25 μm, the 90% cumulative diameter (D ₉₀ ) is 15 μm to 50 μm, preferably 15 μm to 30 μm, and the relative frequency of particle sizes D ₅₀ of less than 10%, preferably adjusted to be 8% or more than 2%. When the particle size distribution of the spray-dried product is in the above range, the positive electrode active material for a lithium secondary battery finally obtained can easily be obtained in the above-described preferable particle size distribution range. In order to obtain a spray-dried product having the particle size distribution, in the spray-drying process according to the present invention, it is particularly important to perform the supply rate of the mixed slurry and the pressure of the spray gas within a predetermined range.

  In addition, the particle size distribution of the spray-dried product is measured by a laser diffraction / scattering method (measuring device: manufactured by Nikkiso Co., Ltd., Microtrac MT3300EXII particle size analyzer, MTEX-SDU, dispersion medium: water, ultrasonic homogenizer for 1 minute). Is a volume frequency particle size distribution. In the frequency particle size distribution measurement, the region between 2000 μm and 0.023 μm is divided into 132 channel particle size distribution bands, the particle distribution is obtained, and the intermediate value of each distribution band is determined as the particle size “D (μm ) ”, And the percentage of the volume of the particles in each distribution band with respect to the total volume of the particles is defined as the frequency value“ P (%) ”of the particles having the particle diameter D (μm).

The supply rate of the slurry is 50 to 150 kg / hour, preferably 50 to 100 kg / hour. In this production method, when the supply rate of the slurry is within the range, it becomes easy to obtain a spray-dried product having a particle size characteristic within the above range. On the other hand, when the slurry supply rate is less than 50 kg / hour, it is difficult to obtain a target particle size. On the other hand, when the slurry supply rate is greater than 150 kg / min, the particle size tends to be larger than the target particle size. Because.

  The pressure of the spray gas is 0.1 MPa or more, preferably 0.2 to 0.5 MPa. This is because the particle size becomes too large when the pressure of the atomizing gas is less than 0.1 MPa. In many cases, air is used as the atomizing gas.

  Further, in the spray drying step, the temperature when drying the droplets obtained from the four-fluid nozzle is 150 to 400 ° C., preferably 200 to 400 ° C. at the inlet temperature of the spray drying device, so that the above particle size characteristics are obtained. It becomes easy to obtain a spray-dried product having

The spray-dried product preferably has a BET specific surface area of 50 to 150 m ² / g, preferably 60 to 90 m ² / g, from the viewpoint of obtaining a product having moderate cohesiveness. BET of the spray-dried product obtained by spray-drying by appropriately selecting the drying conditions such as the drying temperature in the spray-drying step, the solid content concentration, the average particle size of the solid content in the slurry obtained in the wet pulverization step, etc. The specific surface area can be adjusted to the above range.

  A baking raw material mixing process is a process of mixing a spray-dried product and a lithium source to obtain a baking raw material mixture.

The lithium source related to the firing raw material mixing step is not particularly limited, and for example, lithium hydroxide or oxide such as LiOH, Li ₂ O, LiOH · H ₂ O; Li ₂ CO ₃ , LiNO ₃ , LiSO ₄ Inorganic salts of lithium such as organic lithium compounds such as alkyl lithium and lithium acetate. Of these, LiOH, LiOH.H ₂ O, Li ₂ CO _{3 and the} like are preferable as the lithium source.

  The average particle size of the lithium source is preferably 1 to 100 μm, particularly preferably 5 to 80 μm. When the average particle size of the lithium source is in the above range, uniform mixing with the spray-dried product becomes possible, and the reactivity becomes good.

  The mixing amount of the lithium source with respect to the spray-dried product is an atomic conversion molar ratio, and Li / A is 1.20 to 1.80, preferably 1.30 to 1.70, particularly preferably 1.35 to 1. The amount is 65. In addition, A refers to the total number of moles of atomic conversion of nickel, M element, and Me element used as needed.

  The spray-dried product of the present invention obtained by performing the spray-drying process is excellent in reactivity with the lithium source, and therefore the positive electrode for a lithium secondary battery with a small residual amount of lithium carbonate and lithium hydroxide that causes battery swelling. An active material powder can be obtained.

  As a method of mixing the spray-dried product and the lithium source in the firing raw material mixing step, for example, spray drying using mechanical means such as a Henschel mixer, a Nauter mixer, a ribbon blender, a V-type mixer, etc. And a method of mixing the lithium source with the product.

  The firing step is a step of firing a firing raw material mixture to obtain a positive electrode active material powder for a lithium secondary battery made of a lithium nickel-based composite oxide.

  In the firing step, the firing temperature when firing the firing raw material mixture is 900 to 1100 ° C, preferably 950 to 1100 ° C. When the firing temperature of the firing raw material mixture is in the above range, the capacity and capacity retention rate of the lithium secondary battery are increased. The firing time when firing the firing raw material mixture is 2.0 to 20 hours, preferably 5.0 to 15.0 hours. The firing atmosphere when firing the firing raw material root mixture is not particularly limited, and examples include an air atmosphere or an oxygen atmosphere.

And after baking a baking raw material mixture by a baking process, it cools suitably, and if it crushes and / or grinds as needed, the positive electrode active material powder for lithium secondary batteries which consists of the target lithium nickel type complex oxide Is obtained. The crushing and / or pulverization performed as necessary is appropriately performed when the positive electrode active material powder for a lithium secondary battery obtained by firing the firing raw material mixture is in a brittlely bonded block form. Do.
Moreover, in this invention, you may perform baking as many times as desired. Alternatively, for the purpose of making the powder characteristics uniform, the fired material may be pulverized and then refired.

  The average particle size of the solid content in the slurry to be spray-dried, the average particle size of the spray-dried product obtained by performing the spray-drying step, the average particle size of the lithium source mixed in the firing raw material mixing step, and the The average particle diameter of the positive electrode active material powder for a lithium secondary battery obtained by the method for producing a positive electrode active material powder for a lithium secondary battery is an average particle diameter determined by a laser diffraction / scattering method. Nikkiso Co., Ltd., product name: Microtrac MT3300EXII particle size analyzer, model: average particle size measured using MTEX-SDU. In the laser diffraction / scattering method, a slurry or powder dispersed in a dispersion medium is irradiated with laser light, and scattered light incident on the particles is detected by a detector. The scattering angle of the detected scattered light is forward scattering (0 <θ <90 °) for large particles, and side scattering or backscattering (90 ° <θ <180 °) for small particles. From the measured angular distribution value, the particle size distribution is calculated using information such as the incident light wavelength and the refractive index of the particles. Further, the average particle size is calculated from the obtained particle size distribution. For example, a 0.1% by mass sodium hexametaphosphate aqueous solution is used as a dispersant used in the measurement.

  A lithium secondary battery according to the present invention is a lithium secondary battery that uses the positive electrode active material powder for lithium secondary battery as a positive electrode active material, and includes a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte containing a lithium salt. Become. The positive electrode is formed, for example, by applying and drying a positive electrode mixture on a positive electrode current collector, and the positive electrode mixture includes a positive electrode active material, a conductive agent, a binder, and a filler added as necessary. Consists of. In the lithium secondary battery according to the present invention, the positive electrode active material powder for a lithium secondary battery of the present invention is uniformly applied to the positive electrode. For this reason, the lithium secondary battery according to the present invention has a high capacity and particularly excellent cycle characteristics.

  The content of the positive electrode active material contained in the positive electrode mixture is 70 to 100% by mass, preferably 90 to 98% by mass.

  The positive electrode current collector is not particularly limited as long as it is an electronic conductor that does not cause a chemical change in the constituted battery. For example, stainless steel, nickel, aluminum, titanium, calcined carbon, aluminum, and stainless steel Examples of the surface include carbon, nickel, titanium, and silver surface-treated. The surface of these materials may be oxidized and used, or the current collector surface may be provided with irregularities by surface treatment. Examples of the current collector include foils, films, sheets, nets, punched ones, lath bodies, porous bodies, foam bodies, fiber groups, nonwoven fabric molded bodies, and the like. The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm.

  The conductive agent is not particularly limited as long as it is an electron conductive material that does not cause a chemical change in the constructed battery. For example, graphite such as natural graphite and artificial graphite, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, carbon black such as thermal black, conductive fibers such as carbon fiber and metal fiber, Examples include metal powders such as carbon fluoride, aluminum and nickel powder, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive materials such as polyphenylene derivatives. Examples of graphite include scaly graphite, scaly graphite, and earthy graphite. These can be used alone or in combination of two or more. The compounding ratio of the conductive agent is 1 to 50% by mass, preferably 2 to 30% by mass in the positive electrode mixture.

Examples of the binder include starch, polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, regenerated cellulose, diacetylcellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer ( EPDM), sulfonated EPDM, styrene butadiene rubber, fluoro rubber, tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, fluorinated Vinylidene-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene Oroethylene copolymer, polychlorotrifluoroethylene, vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetra Fluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer or its (Na ⁺ ) ion cross-linked product, ethylene-methacrylic acid copolymer or its (Na ⁺ ) Ionic cross-linked product, ethylene-methyl acrylate copolymer or its (Na ⁺ ) ionic cross-linked product, ethylene-methyl methacrylate copolymer or its (Na ⁺ ) ionic cross-linked product, polysaccharides such as polyethylene oxide, heat Plastic tree , Polymers having rubber elasticity, and these may be used individually or in combination. In addition, when using the compound containing a functional group which reacts with lithium like a polysaccharide, it is preferable to add the compound like an isocyanate group and to deactivate the functional group, for example. The blending ratio of the binder is 1 to 50% by mass, preferably 5 to 15% by mass in the positive electrode mixture.

  The filler suppresses the volume expansion of the positive electrode in the positive electrode mixture, and is added as necessary. As the filler, any fibrous material can be used as long as it does not cause a chemical change in the constructed battery. For example, olefinic polymers such as polypropylene and polyethylene, and fibers such as glass and carbon are used. Although the addition amount of a filler is not specifically limited, 0-30 mass% is preferable in a positive mix.

  The negative electrode is formed by applying and drying a negative electrode material on the negative electrode current collector. The negative electrode current collector is not particularly limited as long as it is an electronic conductor that does not cause a chemical change in a configured battery. For example, stainless steel, nickel, copper, titanium, aluminum, calcined carbon, copper or stainless steel Examples of the steel surface include carbon, nickel, titanium, silver surface-treated, and an aluminum-cadmium alloy. Further, the surface of these materials may be used after being oxidized, or the surface of the current collector may be used with surface roughness by surface treatment. Examples of the current collector include foils, films, sheets, nets, punched ones, lath bodies, porous bodies, foam bodies, fiber groups, nonwoven fabric molded bodies, and the like. The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm.

The negative electrode material is not particularly limited, and examples thereof include carbonaceous materials, metal composite oxides, lithium metals, lithium alloys, silicon-based alloys, tin-based alloys, metal oxides, conductive polymers, and chalcogen compounds. And Li—Co—Ni-based materials. Examples of the carbonaceous material include non-graphitizable carbon materials and graphite-based carbon materials. Examples of the metal composite oxide include Sn _P (M ¹ ) _1-p (M ² ) _{q Or} (wherein M ¹ represents one or more elements selected from Mn, Fe, Pb and Ge, M ² represents one or more elements selected from Al, B, P, Si, Group 1, Group 2, Group 3 and a halogen element in the periodic table, and 0 <p ≦ 1, 1 ≦ q ≦ 3 ,. showing a 1 ≦ r ≦ 8), Li x Fe 2 O 3 (0 ≦ x ≦ 1), Li x WO 2 (0 ≦ x ≦ 1), include compounds of lithium titanate. As the metal _{oxide, GeO, GeO 2, SnO,} SnO 2, PbO, PbO 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, Bi 2 O 3 Bi ₂ O ₄ , Bi ₂ O _{5 and the} like. Examples of the conductive polymer include polyacetylene and poly-p-phenylene.

  As the separator, an insulating thin film having a large ion permeability and a predetermined mechanical strength is used. Sheets and non-woven fabrics made of olefin polymers such as polypropylene, glass fibers or polyethylene are used because of their organic solvent resistance and hydrophobicity. The pore diameter of the separator may be in a range generally useful for batteries, for example, 0.01 to 10 μm. The thickness of the separator may be in a general battery range, and is, for example, 5 to 300 μm. In addition, when solid electrolytes, such as a polymer, are used as electrolyte mentioned later, a solid electrolyte may serve as a separator.

  The non-aqueous electrolyte containing a lithium salt is composed of a non-aqueous electrolyte and a lithium salt. As the non-aqueous electrolyte, a non-aqueous electrolyte, an organic solid electrolyte, or an inorganic solid electrolyte is used. Examples of the non-aqueous electrolyte include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, and 2-methyl. Tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 3-methyl -2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, diethyl ether, 1,3- Ropansaruton, methyl propionate, and a solvent obtained by mixing one or more aprotic organic solvents such as ethyl propionate.

  Examples of the organic solid electrolyte include a polyethylene derivative, a polyethylene oxide derivative or a polymer containing the same, a polypropylene oxide derivative or a polymer containing the same, a phosphate ester polymer, polyphosphazene, polyaziridine, polyethylene sulfide, polyvinyl alcohol, polyvinylidene fluoride, Examples thereof include a polymer containing an ionic dissociation group such as polyhexafluoropropylene, and a mixture of a polymer containing an ionic dissociation group and the above non-aqueous electrolyte.

As the inorganic solid electrolytes, nitrides Li, halides, oxygen acid salts, can be used sulfides, for _{example, Li 3 N, LiI, Li} 5 NI 2, Li 3 N-LiI-LiOH, LiSiO 4 _{, LiSiO 4 -LiI-LiOH, Li} 2 SiS 3, Li 4 SiO 4, Li 4 SiO 4 -LiI-LiOH, P 2 S 5, Li 2 S or _{Li 2 S-P 2 S 5} , Li 2 S-SiS ₂ , Li ₂ S—GeS ₂ , Li ₂ S—Ga ₂ S ₃ , Li ₂ S—B ₂ S ₃ , Li ₂ S—P ₂ S ₅ —X, Li ₂ S—SiS ₂ —X, Li ₂ S -GeS in _{2 -X, Li 2 S-Ga} 2 S 3 -X, Li 2 S-B 2 S 3 -X, ( wherein at least X is selected LiI, B ₂ S _3, or from Al ₂ S ₃ One or more).

Further, when the inorganic solid electrolyte is amorphous (glass), lithium phosphate (Li ₃ PO ₄ ), lithium oxide (Li ₂ O), lithium sulfate (Li ₂ SO ₄ ), phosphorus oxide (P ₂ O ₅₎ ), Compounds containing oxygen such as lithium borate (Li ₃ BO ₃ ), Li ₃ PO _4-x N _{2x / 3} (x is 0 <x <4), Li ₄ SiO _4-x N _{2x / 3} (x is Nitrogen such as 0 <x <4), Li ₄ GeO _4-x N _{2x / 3} (x is 0 <x <4), Li ₃ BO _3-x N _{2x / 3} (x is 0 <x <3) The compound to be contained can be contained in the inorganic solid electrolyte. By adding the compound containing oxygen or the compound containing nitrogen, the gap between the formed amorphous skeletons can be widened, the hindrance to movement of lithium ions can be reduced, and ion conductivity can be further improved.

As the lithium salt, those dissolved in the non-aqueous electrolyte are used. For example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiB ₁₀ Cl ₁₀ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium tetraphenylborate, Examples thereof include salts in which one kind or two or more kinds such as imides are mixed.

  Moreover, the compound shown below can be added to a nonaqueous electrolyte for the purpose of improving discharge, a charge characteristic, and a flame retardance. For example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivative, sulfur, quinoneimine dye, N-substituted oxazolidinone and N, N-substituted imidazolidine, ethylene glycol dialkyl ether , Ammonium salt, polyethylene glycol, pyrrole, 2-methoxyethanol, aluminum trichloride, conductive polymer electrode active material monomer, triethylenephosphonamide, trialkylphosphine, morpholine, aryl compounds with carbonyl group, hexamethylphosphine Holic triamide and 4-alkylmorpholine, bicyclic tertiary amine, oil, phosphonium salt and tertiary sulfonium salt, phosphazene, carbonate ester, ionic Body, and the like. In order to make the electrolyte nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride can be included in the electrolyte. In addition, carbon dioxide gas can be included in the electrolytic solution in order to make it suitable for high-temperature storage.

  The lithium secondary battery according to the present invention is a lithium secondary battery excellent in battery performance, particularly in cycle characteristics, and the shape of the battery may be any shape such as a button, a sheet, a cylinder, a corner, or a coin type.

  The use of the lithium secondary battery according to the present invention is not particularly limited. For example, a laptop computer, a laptop computer, a pocket word processor, a mobile phone, a cordless cordless handset, a portable CD player, a radio, an LCD TV, a backup power source, and an electric shaver. And electronic devices such as memory cards and video movies, and consumer electronic devices such as automobiles, electric vehicles, and game machines.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

(Examples 1-4 and Comparative Examples 1-7)
(B) Spray drying step Manganese carbonate (average particle size 27.3 μm) and nickel hydroxide (average particle size 20.3 μm) were weighed so as to have a molar ratio of Ni atoms to Mn atoms as shown in Table 1. Then, pure water was added thereto to prepare a slurry having a solid content concentration of 30% by weight. Next, water is added to a bead mill (Star Mill LMZ4 manufactured by Ashizawa Finetech Co., Ltd.), and zirconia balls having a diameter of 0.5 mm are further charged into the bead mill so that the average particle size of the solid content of the slurry becomes the value shown in Table 1. While controlling the conditions of the crushing strength (peripheral speed), a wet crushing process was performed to prepare a slurry having a solid content of 30% by weight.
The average particle size of the solid content of the slurry was determined by a laser diffraction / scattering method (manufactured by Nikkiso Co., Ltd., Microtrac MT3300EXII particle size analyzer, MTEX-SDU).

Next, in Examples 1 to 4 and Comparative Examples 1 to 6, the supply speed shown in Table 2 was applied to a four-fluid nozzle type spray dryer (Okawara Chemical Machine Nozzle Type Spray Dryer NB12) whose inlet temperature was set to the temperature shown in Table 2. Various slurries were supplied at the pressure of the spray gas and the airflow ratio to obtain a spray-dried product. Moreover, in Comparative Example 7, various types of slurries were supplied to the disk-type spray dryer (Okawara Kaoki Spray Dryer OC30) whose inlet temperature was set to the temperature shown in Table 2 at the supply speed, spray gas pressure, and airflow ratio shown in Table 2. To obtain a spray-dried product. Table 3 shows various physical properties of the obtained spray-dried product.
The particle size distribution of the spray-dried product and the positive electrode active material powder of the lithium secondary battery described later is determined by laser diffraction / scattering method (manufactured by Nikkiso Co., Ltd., Microtrac MT3300EXII particle size analyzer, MTEX-SDU, dispersion medium: water, ultrasonic homogenizer). 1 minute pretreatment) and the volume frequency particle size distribution was measured. In the volume frequency particle size distribution measurement, particles between 2000 μm and 0.023 μm were divided into 132 channel particle size distribution bands shown in Table 8. The particle size distribution diagrams of the spray-dried products obtained in Example 1 and Comparative Example 1 are shown in FIGS. 3 and 4, respectively.

(B) Firing raw material mixing step This spray-dried product and lithium carbonate (average particle size 6.1 μm) are in a molar ratio of Li atoms to the total atomic moles (A) of Ni atoms and Mn atoms in the spray-dried product. (Li / A) is weighed so as to have the blending ratio shown in Table 3, and is mixed for 15 seconds at a rotation speed of 20,000 rotations per minute using a household mixer (IFM-660DG, manufactured by Iwatani) as a mixing device. The process was performed and the baking raw material mixture was obtained.

(C) Firing step The calcined raw material mixture obtained above is calcined in an air furnace in the atmosphere, at the temperature and time shown in Table 4, and after cooling, the calcined product is pulverized and classified to obtain a lithium nickel composite oxide. A sample was obtained.

<Evaluation of physical properties of lithium nickel composite oxide>
The color difference, particle size distribution, BET specific surface area, tap density, Li ₂ CO ₃ content, and LiOH content were determined for the lithium nickel composite oxides obtained in the examples and comparative examples. The results are shown in Tables 5 and 6. Moreover, the particle size distribution diagrams of the lithium nickel composite oxide obtained in Example (1) and Comparative Example (1) are shown in FIGS. 5 and 6 and the lithium nickel composite oxide obtained in Example (1). X-ray diffraction patterns are shown in FIG.
(Color difference measurement)
A lithium nickel-based composite oxide sample is filled in a special petri dish, and the L ^* value, a ^* value, and b ^* value are measured three times using a spectral color difference meter (Nippon Denshoku, SE2000). The average value was obtained.
(Measurement of particle distribution)
This was determined by a laser diffraction / scattering method (manufactured by Nikkiso Co., Ltd., Microtrac MT3300EXII particle size analyzer, MTEX-SDU, LOW-WET MT3000II MODE).
(Measurement of tap density)
Dry the graduated cylinder completely and weigh the empty graduated cylinder. About 40 g of sample is weighed on the medicine wrapping paper. Using a funnel, transfer the sample into a 50 ml graduated cylinder. Automatic graduated cylinder Set on D measuring device (Yuasa Ionics Co., Ltd., dual auto tap), adjust tapping frequency to 500, perform tapping, read scale on sample surface, measure weight of graduated cylinder and calculate ( (Tapping height 3.2mm, tapping pace 200 times / min)
(Measurement of Li ₂ CO ₃ content and LiOH content)
5 g of a sample to be measured and 100 g of pure water were weighed in a beaker and stirred for 5 minutes using a magnetic stirrer. Next, the sample solution after stirring was filtered, and 30 ml of the filtrate was titrated with 0.1 N HCl with an automatic titrator (model COMMITITE-2500) to calculate the Li ₂ CO ₃ content and the LiOH content.

<Battery performance test>
(1) Production of Lithium Secondary Battery A positive electrode obtained by mixing 95% by mass of the lithium nickel composite oxide obtained in Examples and Comparative Examples, 2.5% by mass of graphite powder, and 2.5% by mass of polyvinylidene fluoride. A kneading paste was prepared by dispersing this in N-methyl-2-pyrrolidinone. The kneaded paste was applied to an aluminum foil, dried, pressed and punched into a disk with a diameter of 15 mm to obtain a positive electrode plate.
Using this positive electrode plate, a coin-type lithium secondary battery was manufactured using each member such as a separator, a negative electrode, a positive electrode, a current collector plate, a mounting bracket, an external terminal, and an electrolytic solution. Among these, a metal lithium foil was used for the negative electrode, and 1 mol of LiPF ₆ was dissolved in 1 liter of 25:60:15 kneaded solution of ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate.

(2) Evaluation of battery performance The produced lithium secondary battery was operated at room temperature (25 ° C) under the following conditions, and the following battery performance was evaluated.
<Evaluation of cycle characteristics>
After charging the positive electrode to 4.8 V at 0.5 C for 5 hours by constant current voltage (CCCV) charging, charging and discharging to discharge to 2.7 V at a discharge rate of 0.2 C are performed. As one cycle, the discharge capacity for each cycle was measured. This cycle was repeated 20 times, and the capacity retention rate was calculated from the following formula (4) from the discharge capacities of the first and 20th cycles. The discharge capacity at the first cycle was defined as the initial discharge capacity. The results are shown in Table 7.
Capacity maintenance rate (%) =
(Discharge capacity at 20th cycle / discharge capacity at 1st cycle) × 100 (4)

DESCRIPTION OF SYMBOLS 1; 4 Fluid nozzle 2a, 2b; Liquid flow path 3a, 3b; Gas flow path 4a; Focal point 4 of edge tip; Compressed air 5; Spray liquid 6; Fluid flow surface 7; Drying chamber 8;

Claims (8)

The following general formula:
_{xLi 2 MO 3 · (1-} x) Li [Ni 1-y-z M y Me z] O 2 (1)
(In the formula, M represents a metal element selected from Mn, Ti and Zr. Me represents an element having an atomic number of 11 or more other than Mn, Ti, Zr and Ni . X represents 0.4 ≦ x ≦ 0. 6 and y are 0 ≦ y ≦ 0.6, and z is 0 ≦ z ≦ 0.1.), And L in the L ^* a ^* b ^* color system, ^* value from 15.0 to 25.0, a value ^* is 1.00-15.0, ^{b *} value Ri der -5.0～5.0, average particle diameter determined from the particle size distribution measurement ( D ₅₀ ) is 1 μm or more and 30 μm or less, 10% cumulative diameter (D ₁₀ ) is 1 μm or more and 10 μm or less, 90% cumulative diameter (D90) is 15 μm or more and 50 μm or less, and the relative frequency in the particle size of D50 is 10% or less. A positive electrode active material powder for a lithium secondary battery. The positive electrode active material powder for lithium secondary battery according to claim 1, wherein the tap density of 0.5 g / cm ³ or more. BET specific surface area is 0.5-3.0 m < ² > / g, The positive electrode active material powder for lithium secondary batteries as described in any one of Claim 1 or 2 characterized by the above-mentioned. Content of the remaining lithium carbonate is 0.5 mass% or less, The positive electrode active material powder for lithium secondary batteries as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned. The positive electrode active material powder for a lithium secondary battery according to claim 4 , wherein the content of the remaining lithium hydroxide is 0.5 mass% or less. The following general formula:
_{xLi 2 MO 3 · (1-} x) Li [Ni 1-y-z M y Me z] O 2 (1)
(In the formula, M represents a metal element selected from Mn, Ti and Zr. Me represents an element having an atomic number of 11 or more other than Mn, Ti, Zr and Ni . X represents 0.4 ≦ x ≦ 0. 6 and y are 0 <y ≦ 0.6, and z is 0 ≦ z ≦ 0.1.) A method for producing a positive electrode active material for a lithium secondary battery comprising a lithium nickel composite oxide. And
A slurry containing a nickel source and an M source, or a nickel source, an M source and a Me source and having an average solid content of 0.1 to 2.0 μm in a spray drying apparatus equipped with a four-fluid nozzle, A spray-drying step in which the feed rate is 50 to 150 kg / hour and the pressure of the spray gas is 0.1 MPa or more to obtain a spray-dried product by spray-drying, and then the spray-dried product and the lithium source are mixed. A firing raw material mixing step for obtaining a firing raw material mixture;
A firing step of firing the firing raw material mixture to obtain a positive electrode active material powder for a lithium secondary battery comprising the lithium nickel-based composite oxide represented by the general formula (1);
Have a, the spray-dried product with an average particle diameter determined from the particle size distribution measurement value _{(D 50)} is 1.0μm or more 30.0μm or less, 10% cumulative diameter _{(D 10)} is 1.0μm or more 10.0μm In the following, lithium _{90 having} a 90% cumulative diameter (D ₉₀ ) of not less than 15.0 μm and not more than 50.0 μm and a relative frequency in the particle size of D ₅₀ adjusted to 10.0% or less. Manufacturing method of positive electrode active material powder for secondary battery. The method for producing a positive electrode active material powder for a lithium secondary battery according to claim 6 , wherein the spraying temperature is 150 to 400 ° C. A lithium secondary battery obtained by using the positive electrode active material powder for a lithium secondary battery according to any one of claims 1 to 5 as a positive electrode active material.