JP6509581B2 - Transition metal-containing carbonate compound, method for producing the same, method for producing positive electrode active material, and positive electrode for lithium ion secondary battery and lithium ion secondary battery - Google Patents

Description

  The present invention relates to a transition metal-containing carbonate compound, a method for producing the same, a method for producing a positive electrode active material, and a positive electrode for a lithium ion secondary battery and a lithium ion secondary battery.

As a positive electrode active material contained in the positive electrode of a lithium ion secondary battery, a lithium-containing composite oxide, in particular, LiCoO ₂ is well known. However, in recent years, size reduction and weight reduction are required for portable electronic devices and lithium ion secondary batteries for vehicles, and the discharge capacity of lithium ion secondary batteries per unit mass of positive electrode active material (hereinafter simply referred to as discharge) Further improvement of the capacity is also required. As a positive electrode active material capable of further increasing the discharge capacity of a lithium ion secondary battery, a positive electrode active material having a high content of Li and Mn, that is, a so-called lithium-rich positive electrode active material attracts attention.

  The positive electrode active material is usually produced by mixing a transition metal compound (carbonate or hydroxide), a so-called precursor, and a lithium compound, and calcining the obtained mixture to obtain a lithium-containing composite oxide. Ru. As the precursor, a transition metal-containing carbonate compound is suitable in that a positive electrode active material having a large specific surface area is obtained, and as a result, a lithium ion secondary battery having good battery characteristics is obtained.

  The transition metal-containing carbonate compound is, for example, a reaction vessel while continuously supplying an aqueous solution containing either one or both of Ni ion and Co ion and Mn ion and an aqueous solution containing carbonate ion to the reaction vessel. The mixture liquid is stirred to precipitate the transition metal-containing carbonate compound, and at the same time, the mixture liquid is withdrawn through the filter medium to concentrate the transition metal-containing carbonate compound to grow particles of the transition metal-containing carbonate compound; It is manufactured by the so-called concentration method.

  However, transition metal-containing carbonate compounds obtained by the concentration method have the problem of low circularity. When a transition metal-containing carbonate compound having a low degree of circularity is used as a precursor, a lithium-containing composite oxide having a low degree of circularity can be obtained. When a lithium-containing composite oxide having a low degree of circularity is used as a positive electrode active material, the density of the positive electrode active material in the positive electrode decreases, and therefore the discharge capacity of the lithium ion secondary battery per unit volume of the positive electrode active material becomes insufficient. .

The following method has been proposed as a method for producing a transition metal-containing carbonate compound close to a spherical shape.
Using an apparatus having an external circulation path for extracting a part of the mixed solution in the reaction tank and returning it to the reaction tank, the flow rate in the external circulation path is set to 1 m / sec or more, Ni ions and Mn in the middle of the external circulation path A method of supplying an aqueous solution containing ions, an aqueous solution containing carbonate ions, and the like (Patent Document 1).

However, the transition metal-containing carbonate compound obtained by the method described in Patent Document 1 has a problem that the particle size distribution is wide (D ₉₀ / D ₁₀ is large). When a transition metal-containing carbonate compound having a wide particle size distribution is used as a precursor, a lithium-containing composite oxide having a wide particle size distribution can be obtained. Since the positive electrode active material composed of a lithium-containing composite oxide having a wide particle size distribution has many coarse particles, the coatability at the time of applying the slurry containing the positive electrode active material to the positive electrode current collector is deteriorated. In addition, after the slurry containing the positive electrode active material is coated on the positive electrode current collector, the coarse particles are easily broken when rolling, and the cycle characteristics of the lithium ion secondary battery become insufficient.

International Publication No. 2013/111487

  The present invention can produce a transition metal-containing carbonate compound having high circularity and narrow particle size distribution; Transition metal-containing carbonate compound having high circularity and narrow particle size distribution; Lithium having high circularity and narrow particle size distribution Method of manufacturing a positive electrode active material containing a composite oxide containing the same; positive electrode for lithium ion secondary battery capable of improving discharge capacity and cycle characteristics of lithium ion secondary battery; Lithium ion secondary battery having good discharge capacity and cycle characteristics The purpose is to provide

The present invention has the following aspects.
[1] (a) A step of continuously or intermittently supplying the following aqueous solution A, the following aqueous solution B and the following seed crystal solution C to the reaction tank respectively and (b) while performing the step (a) Stir a mixed solution containing the following aqueous solution A, the following aqueous solution B and the following seed crystal solution C supplied to the reaction vessel to grow a transition metal-containing carbonate compound containing either one or both of Ni and Co and Mn. And (c) a step of continuously or intermittently extracting a part of the mixed solution containing the transition metal-containing carbonate compound in the reaction vessel while carrying out the step (b). And a method of producing a transition metal-containing carbonate compound.
Aqueous solution A: an aqueous solution containing either or both of Ni ions and Co ions and Mn ions.
Aqueous solution B: aqueous solution containing carbonate ion.
Seed solution C: A solution containing seed crystals consisting of a carbonate compound containing either or both of Ni and Co and Mn, and having a D ₅₀ of less than 5 μm.
[2] In the step (a), the aqueous solution A and the seed crystal solution C are simultaneously supplied to the reaction vessel, and the pH of the liquid mixture in the reaction vessel is in the range of 7 to 9 in the aqueous solution B. The method for producing a transition metal-containing carbonate compound according to [1], wherein the transition metal-containing carbonate compound is supplied continuously or intermittently so that the fluctuation is within ± 0.2.
[3] The method for producing a transition metal-containing carbonate compound of [1] or [2], wherein in the step (b), the transition metal-containing carbonate compound is grown until D ₅₀ becomes ₅ to 15 μm.
[4] In the step (b), the mixed solution containing the aqueous solution A, the aqueous solution B and the seed crystal solution C supplied to the reaction vessel is in the range of 30 to 50 ° C. and the fluctuation range is ± 2 The manufacturing method of the transition metal containing carbonate compound in any one of [1]-[3] which hold | maintains, hold | maintaining at (C).
[5] A seed crystal comprising the carbonate compound, wherein the seed crystal solution C stirs the mixed solution while supplying the aqueous solution A and the aqueous solution B continuously or intermittently to the seed crystal solution preparation tank, respectively. The manufacturing method of the transition metal containing carbonate compound in any one of [1]-[4] which is obtained by depositing.
[6] Ni _x Co _y Mn _z M _(1-x-y-z) CO ₃ (where x is 0.15 to 0.5, y is 0 to 0.33, and z is 0.33 to 0.85, x + y + z is 1 or less, and M is Mg, Ca, Ba, Sr, Al, Cr, Fe, Ti, Zr, Y, Nb, Mo, Ta, W, And one or more selected from the group consisting of Ce and La. The values at a 50% cumulative frequency of circularity are 0.970 or more, and D ₉₀ / D ₁₀ is 2 to 6. , Transition metal-containing carbonate compounds.
[7] The transition metal-containing carbonate compound of [6], wherein D ₅₀ is ₅ to 15 μm.
[8] A method for producing a positive electrode active material containing a lithium-containing composite oxide, wherein (d) a transition obtained by the method for producing a transition metal-containing carbonate compound according to any one of the above [1] to [5]. Having a step of mixing the metal-containing carbonate compound, or the transition metal-containing carbonate compound of the above [6] or [7] and a lithium compound, and calcining the obtained mixture to obtain a lithium-containing composite oxide, Method of manufacturing positive electrode active material.
[9] The lithium-containing composite oxide includes Li _α Ni _x Co _y Mn _z M _(1-xyz) O _β (wherein α is 1.1 to 1.7 and x is 0.15 to 0.5, y is 0 to 0.33, z is 0.33 to 0.85, x + y + z is 1 or less, and β is Li, Ni, Co , And the number of moles of oxygen element (O) necessary to satisfy the valences of Mn and M).
[10] A positive electrode active material layer including the positive electrode active material obtained by the method of producing a positive electrode active material according to the above [8] or [9], a conductive material, and a binder is formed on a positive electrode current collector Positive electrode for lithium ion secondary battery.
[11] A lithium ion secondary battery comprising the positive electrode for a lithium ion secondary battery of the above [10], a negative electrode, and a non-aqueous electrolyte.

According to the method for producing a transition metal-containing carbonate compound of the present invention, it is possible to produce a transition metal-containing carbonate compound having a high degree of circularity and a narrow particle size distribution.
The transition metal-containing carbonate compound of the present invention has a high degree of circularity and a narrow particle size distribution.
According to the method for producing a positive electrode active material of the present invention, it is possible to produce a positive electrode active material containing a lithium-containing composite oxide having a high degree of circularity and a narrow particle size distribution.
The positive electrode for a lithium ion secondary battery of the present invention can improve the discharge capacity and cycle characteristics of the lithium ion secondary battery.
The lithium ion secondary battery of the present invention has good discharge capacity and cycle characteristics.

It is a schematic block diagram which shows an example of a seed crystallization liquid preparation apparatus. It is a schematic block diagram which shows the other example of a seed-crystal liquid preparation apparatus. It is a schematic block diagram which shows the other example of a seed-crystal liquid preparation apparatus. It is a schematic block diagram which shows an example of the manufacturing apparatus used for the manufacturing method of the transition metal containing carbonate compound of this invention.

The following definitions of terms apply throughout the specification and claims.
“D ₅₀ ” is a particle diameter at a point of 50% in the cumulative volume distribution curve where the total volume of the particle size distribution determined on a volume basis is 100%, that is, the volume based cumulative 50% diameter.
“D ₁₀ ” is a particle diameter at a point of 10% in the cumulative volume distribution curve where the total volume of the particle size distribution determined on a volume basis is 100%, that is, a volume based cumulative 10% diameter.
“D ₉₀ ” is the particle diameter at a point of 90% in the cumulative volume distribution curve where the total volume of the particle size distribution determined on a volume basis is 100%, that is, the volume-based cumulative 90% diameter.
The “particle size distribution” is obtained from the frequency distribution and the cumulative volume distribution curve measured by a laser scattering particle size distribution measuring apparatus (for example, a laser diffraction / scattering type particle size distribution measuring apparatus etc.). The measurement is carried out by sufficiently dispersing the powder in an aqueous medium by ultrasonic treatment or the like.
“Circularity” is the ratio (X / Y) of the circumference X of the circle equal to the area of the projected image of the particle and the circumference Y of the projected image of the particle, and the value is in the range of 0 to 1 Become. As the degree of circularity is closer to 1, the shape is closer to a circle. The degree of circularity is determined by an apparatus (for example, a flow type particle image analyzer etc.) which is calculated using an image analysis method.
“Value at the 50% cumulative frequency of circularity” means the circularity for all particles in the image, the horizontal axis is the circularity (0 to 1), and the vertical axis is the cumulative frequency of circularity (0 to 1) The distribution curve which is 100%) is created, and the distribution curve is obtained by reading the value of the degree of circularity when the cumulative frequency is 50%.
"Specific surface area" is a value measured by the BET (Brunauer, Emmet, Teller) method. In the measurement of the specific surface area, nitrogen gas is used as the adsorption gas.
The notation “Li” indicates that the element is not elemental Li but the element Li unless otherwise noted. The same applies to the other elements such as Ni, Co and Mn.
The compositional analysis of the transition metal-containing carbonate compound and the lithium-containing composite oxide is performed by inductively coupled plasma analysis (hereinafter referred to as ICP). Further, the ratio of the elements of the lithium-containing composite oxide is a value in the lithium-containing composite oxide before the first charge (also referred to as activation treatment).

<Method of producing transition metal-containing carbonate compound>
The method for producing a transition metal-containing carbonate compound of the present invention comprises the following step (a), the following step (b) and the following step (c).
(A) A step of continuously or intermittently supplying an aqueous solution A, an aqueous solution B and a seed crystal solution C and, if necessary, another solution D to the reaction vessel.
(B) Stirring the mixed solution containing the aqueous solution A, the aqueous solution B and the seed crystal solution C supplied to the reaction vessel while carrying out the step (a), one or both of Ni and Co and Mn Growing the transition metal-containing carbonate compound.
(C) A step of continuously or intermittently withdrawing a portion of the mixed solution containing the transition metal-containing carbonate compound in the reaction vessel from the reaction vessel while carrying out the step (b).

(Aqueous solution A)
The aqueous solution A is an aqueous solution containing metal ions, and contains either or both of Ni ions and Co ions and Mn ions.
The aqueous solution A is optionally one or more members selected from the group consisting of Mg, Ca, Ba, Sr, Al, Cr, Fe, Ti, Zr, Y, Nb, Mo, Ta, W, Ce and La. It may contain ions of other metals M.

As the aqueous solution A, either or both of Ni sulfate and Co sulfate and Mn sulfate are preferable because the material cost is relatively low and a positive electrode active material having excellent powder properties can be obtained. Is preferably dissolved in water.
Examples of the sulfate of Ni include nickel (II) sulfate hexahydrate, nickel (II) sulfate heptahydrate, and nickel (II) ammonium sulfate hexahydrate.
Examples of the sulfate of Co include cobalt (II) sulfate heptahydrate, cobalt (II) ammonium sulfate hexahydrate and the like.
Examples of the sulfate of Mn include manganese (II) sulfate pentahydrate, manganese (II) ammonium sulfate hexahydrate and the like.

  The ratio of Ni ions, Co ions, Mn ions and M ions in the aqueous solution A is the same as the ratio of Ni, Co, Mn and M contained in the transition metal-containing carbonate compound.

  0.1-3 mol / kg is preferable and, as for the density | concentration of the sum total of the metal ion in the aqueous solution A, 0.5-2.5 mol / kg is more preferable. If the total concentration of metal ions is equal to or higher than the lower limit value, productivity can be increased. If the total concentration of the metal ions is below the upper limit value, the metal ions can be sufficiently dissolved in water.

(Aqueous solution B)
The aqueous solution B is an aqueous solution containing carbonate ions.
The aqueous solution B is one of the raw materials of the transition metal-containing carbonate compound, and also plays a role as a pH adjuster for precipitating the transition metal-containing carbonate compound.

As the aqueous solution B, at least one carbonate selected from the group consisting of carbonates of Na and carbonates of K is dissolved in water from the viewpoint of relatively low material cost and easy preparation of the aqueous solution B Is preferred.
Examples of carbonates of Na include sodium carbonate and sodium hydrogen carbonate.
Examples of the carbonate of K include potassium carbonate and potassium hydrogen carbonate.
As the carbonate, sodium carbonate and potassium carbonate are preferable from the viewpoint of being inexpensive and easy to control the particle diameter of the transition metal-containing carbonate compound.

  0.1-3 mol / kg is preferable and, as for the density | concentration of the sum total of the carbonate ion in the aqueous solution B, 0.5-2.5 mol / kg is more preferable. If the total concentration of carbonate ions is within the above range, it is easy to precipitate the transition metal-containing carbonate compound.

(Seed solution C)
The seed crystal solution C is a solution containing a seed crystal consisting of a carbonate compound containing either or both of Ni and Co and Mn, and having a D ₅₀ of less than 5 μm. Then, in the seed crystal solution C, seed crystals are dispersed in a dispersion medium. The composition of the seed crystals may be the same as or different from the composition of the transition metal-containing carbonate compound obtained by the production method of the present invention. The composition of the seed crystals is preferably the same as the composition of the transition metal-containing carbonate compound obtained by the production method of the present invention.

The seed crystal D ₅₀ is less than 5 μm, preferably 1 to 4 μm, and more preferably 1.5 to 3.5 μm. When the seed crystal D ₅₀ is less than 5 μm, the particle size distribution of the seed crystals becomes narrow, and as a result, the particle size distribution of the transition metal-containing carbonate compound obtained by growing the seed crystals also becomes narrow. Furthermore, if seed crystals of D ₅₀ is 1μm or more, seed crystals in step (b) it is likely to grow larger transition metal-containing carbonate compound particle size.

  1-50 mass% is preferable, and, as for solid content concentration of the seed crystal solution C, 5-35 mass% is more preferable. If the solid content concentration is 1% by mass or more, the productivity of the transition metal-containing carbonate compound can be increased. If the solid content concentration is 50% by mass or less, it is easy to handle as a liquid.

(Other solution D)
Other solutions D include, for example, aqueous solutions containing ammonia or ammonium salts. The aqueous solution containing ammonia or ammonium salt functions to adjust the pH and the solubility of the transition metal element. Examples of ammonium salts include ammonium chloride, ammonium sulfate and ammonium nitrate. Preferably, the ammonia or ammonium salt is supplied to the mixture simultaneously with the supply of the aqueous solution A.

(solvent)
As a solvent of the aqueous solution A, the aqueous solution B, and the other solution D, and as a dispersion medium of the seed crystal solution C, water is preferable. If the sulfate and carbonate can be dissolved, a mixed medium containing an aqueous medium other than water with an upper limit of 20% based on the total mass of the solvent may be used as the solvent.
Examples of the aqueous medium other than water include methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, butanediol, glycerin and the like.

(Step of preparing seed crystal solution C)
The seed crystal solution C is prepared, for example, by mixing the aqueous solution A and the aqueous solution B, and optionally, the other solution D, reacting transition metal ions and carbonate ions, and either or both of Ni and Co and Mn. It can obtain by precipitating the seed crystal which consists of the carbonate compound which contains.

Examples of the method of preparing a seed crystal solution C containing seed crystals having a D ₅₀ of less than 5 μm include the following methods (i) to (iii). Either method is a method of forming seed crystals with a D ₅₀ of less than 5 μm while grinding particles of a growing carbonate compound.
(I) A method of preparing seed crystal solution C while irradiating ultrasonic waves.
(Ii) A method of preparing seed crystal solution C while stirring the mixture using a shaft generator that applies a shear force to the mixture.
(Iii) A method of preparing seed crystal solution C while passing the mixture through an external circulation line provided with a circulating ultrasonic homogenizer in the middle.

FIG. 1 is a schematic configuration view showing an example of a seed crystal solution preparation apparatus used for the method (i).
The seed crystal solution preparation apparatus 1a includes a seed crystal solution preparation tank 10 with a baffle, a stirring device with a two-stage inclined paddle type stirring blade 12 for stirring the mixture in the seed crystal solution preparation tank 10, and a seed crystal solution. An aqueous solution A supply line 14 for supplying the aqueous solution A to the preparation tank 10, an aqueous solution B supply line 16 for supplying the aqueous solution B to the seed crystal solution preparation tank 10, and a part of the mixture in the seed crystal solution preparation tank 10 Then, the mixed solution circulation line 20 returned to the seed crystal preparation tank 10, the pump 22 provided on the mixed solution circulation line 20, and the mixed solution circulation line 20 on the downstream side of the pump 22 , A filtrate discharge line 26 for discharging the liquid that has passed through the filter material of the MF membrane module 24, a pump 28 provided in the middle of the filtrate discharge line 26, a seed crystal solution preparation tank Water bath 30 heating 10 from the outside Includes an ultrasonic irradiation means provided together in a water bath 30 (not shown), and a mixed liquid discharge line for discharging a mixture of TaneAkiraeki preparation tank 10 (not shown).

FIG. 2 is a schematic configuration view showing an example of a seed crystal solution preparation apparatus used for the method (ii).
The seed crystal preparation apparatus 1 b includes a seed crystal preparation tank 10 with a baffle, a shaft generator 32 for stirring the mixture in the seed crystal preparation tank 10, and an aqueous solution for supplying the aqueous solution A to the seed crystal preparation tank 10. After extracting a part of the mixed solution in the seed crystal solution preparation tank 10 and the aqueous solution B feed line 16 for supplying the aqueous solution B to the seed crystal solution preparation tank 10 with the A supply line 14 and the seed crystal solution preparation tank 10 A mixed solution circulation line 20 to be returned to the pump, a pump 22 provided in the middle of the mixed solution circulation line 20, and an MF membrane module 24 provided in the middle of the mixed solution circulation line 20 and downstream of the pump 22; A filtrate discharge line 26 for discharging the liquid that has passed through the filter material of the MF membrane module 24, a pump 28 provided in the middle of the filtrate discharge line 26, and a hot water bath 30 for heating the seed crystal preparation tank 10 from the outside , Seed crystal solution preparation tank 1 And a mixed liquid discharge line for discharging (not shown) the mixture of the inner.

FIG. 3 is a schematic configuration view showing an example of a seed crystal solution preparation apparatus used for the method (iii).
The seed crystal preparation apparatus 1c includes a seed crystal preparation tank 10 with a baffle, a stirrer with a two-stage inclined paddle type stirring blade 12 for stirring the mixture in the seed crystal preparation tank 10, and a seed crystal preparation An aqueous solution A supply line 14 for supplying the aqueous solution A to the preparation tank 10, an aqueous solution B supply line 16 for supplying the aqueous solution B to the seed crystal solution preparation tank 10, and a part of the mixture in the seed crystal solution preparation tank 10 Then, the mixed solution circulation line 20 returned to the seed crystal preparation tank 10, the pump 22 provided on the mixed solution circulation line 20, and the mixed solution circulation line 20 on the downstream side of the pump 22 And the filter material of the MF membrane module 24 and the MF membrane module 24 provided in the middle of the mixed solution circulation line 20 and on the downstream side of the circulation ultrasonic homogenizer 34 and the filter medium of the MF membrane module 24. Drain the fluid A filtrate discharge line 26, a pump 28 provided in the middle of the filtrate discharge line 26, and a mixed solution extraction line 36 for extracting a part of the mixed solution in the seed crystal preparation tank 10 without passing through a filter medium; And a water bath 30 for heating the seed crystal preparation tank 10 from the outside.

  The MF membrane module 24 is provided with a filter medium (hollow fiber membrane, ceramic membrane, etc.), and a part of the mixed solution not containing seed crystals that has passed through the filter medium is sent to the filtrate discharge line 26 and seed crystals not passed through the filter medium. The remaining portion (concentrated liquid) of the mixed liquid containing the above is returned to the mixed liquid circulation line 20 on the downstream side.

  When the aqueous solution A and the aqueous solution B are supplied to the seed crystal preparation tank 10, the seed crystal preparation tank 10 is preferable because it is easy to precipitate the seed crystal composed of a carbonate compound and to control the particle diameter of the seed crystal. It is preferable to add the aqueous solution A and the aqueous solution B continuously or intermittently, respectively, and it is more preferable to add at least the aqueous solution A continuously.

  When mixing the aqueous solution A and the aqueous solution B in the seed crystal preparation tank 10, it is preferable to carry out while stirring. As a drive source of a stirring apparatus, a three-one motor etc. are mentioned, for example. As a stirring blade of a stirring apparatus, stirring blades, such as an anchor type and a propeller type, are mentioned besides the paddle type of the example of illustration.

  Therefore, as the seed crystal solution C, the aqueous solution A and the aqueous solution B supplied to the seed crystal solution preparation tank 10 while the aqueous solution A and the aqueous solution B are continuously or intermittently supplied to the seed crystal solution preparation tank 10 respectively. It is preferable that the liquid mixture contained in the mixture is stirred to precipitate seed crystals of a carbonate compound.

When the aqueous solution A and the aqueous solution B are supplied to the seed crystal preparation tank 10, it is preferable to previously add ion exchanged water, pure water, distilled water or the like to the seed crystal preparation tank 10.
When the aqueous solution A and the aqueous solution B are supplied to the seed crystal preparation tank 10, it is more preferable to control the pH of the mixture in the seed crystal preparation tank 10 using the aqueous solution B or another solution D.

7-9 are preferable from a point which a carbonate compound tends to precipitate, and, as for pH of the liquid mixture in the seed crystal solution preparation tank 10, 7.5-8.5 are more preferable.
The fluctuation range of the pH of the mixture in the seed crystal preparation tank 10 is preferably ± 0.2, more preferably ± 0.1, from the viewpoint of sufficiently narrowing the particle size distribution of the seed crystals.

The temperature of the mixture in the seed crystal preparation tank 10 is preferably 20 to 70 ° C., and more preferably 30 to 50 ° C., from the viewpoint that the carbonate compound tends to precipitate.
The range of fluctuation of the temperature of the mixture in the seed crystal preparation tank 10 is preferably ± 2 ° C., more preferably ± 1 ° C., from the viewpoint of sufficiently narrowing the particle size distribution of the seed crystals.

  When mixing the aqueous solution A and the aqueous solution B in the seed crystal preparation tank 10, mixing is preferably performed under a nitrogen gas atmosphere or an argon gas atmosphere from the viewpoint of suppressing the oxidation of the seed crystals, which is a cost aspect. It is more preferable to mix under nitrogen gas atmosphere.

  The precipitation of seed crystals consisting of a carbonate compound may be a method (concentration method) of extracting a part of the mixture in the seed crystal preparation tank 10 through a filter medium and concentrating the mixture (concentration method). The method may be a method (overflow method) in which a part of the mixed liquid in the liquid preparation tank 10 is extracted together with seed crystals without using a filter medium to keep the concentration of the seed crystals low.

(manufacturing device)
FIG. 4 is a schematic configuration view showing an example of a production apparatus used in the method for producing a transition metal-containing carbonate compound of the present invention.
The manufacturing apparatus includes a seed crystal solution preparation apparatus 1, a seed crystal solution storage tank 2 storing the seed crystal solution C prepared by the seed crystal solution preparation apparatus 1, and a seed crystal supplied from the seed crystal solution storage tank 2 Transfer the seed crystal solution C prepared in the seed crystal solution preparation apparatus 1 to the seed crystal solution storage tank 2 with the particle growth apparatus 3 for growing the seed crystals in the solution C into the transition metal-containing carbonate compound having a large particle diameter The first seed crystal liquid transfer line 4 and the second seed crystal liquid transfer line 5 for transferring the seed crystal liquid C stored in the seed crystal liquid storage tank 2 to the particle growth apparatus 3 are provided.

Examples of the seed crystal preparation device 1 include the above-described seed crystal preparation device 1a, the seed crystal preparation device 1b, and the seed crystal preparation device 1c.
The particle growth apparatus 3 includes a reaction vessel 40 with a baffle, a stirring device with a two-stage inclined paddle type stirring blade 42 for stirring the mixture in the reaction vessel 40, and an aqueous solution A for supplying the aqueous solution A to the reaction vessel 40. A supply line 44, an aqueous solution B supply line 46 for supplying the aqueous solution B to the reaction tank 40, a seed crystal liquid C supply line 48 for supplying the seed crystal liquid C to the reaction tank 40, and one of the mixed liquids in the reaction tank 40 And a pump 52 provided in the middle of the mixed liquid extraction line 50, and a heating means (not shown) for heating the reaction tank 40 from the outside.

(Step (a))
The aqueous solution A, the aqueous solution B and the seed solution C are continuously or intermittently supplied to the reaction vessel 40, respectively. In the step (a), in addition to the above liquid, another solution D may be supplied continuously or intermittently as needed.

  When the aqueous solution A, the aqueous solution B and the seed crystal solution C are supplied to the reaction tank 40, the seed crystals are easily grown into a transition metal-containing carbonate compound having a large particle diameter in step (b), and the transition metal-containing carbonate It is preferable to add the aqueous solution A, the aqueous solution B, and the seed crystal solution C to the reaction tank 40 continuously or intermittently from the viewpoint of easily controlling the particle diameter of the compound. Among them, it is more preferable to add the aqueous solution A and the seed crystal solution C continuously.

  When the aqueous solution A, the aqueous solution B and the seed crystal solution C are supplied to the reaction vessel 40, at least the aqueous solution A is added to the reaction vessel 40 in order to increase the circularity of the transition metal-containing carbonate compound and to narrow the particle size distribution. It is preferable to simultaneously supply the seed crystal solution C. It is more preferable to simultaneously supply the aqueous solution A, the aqueous solution B and the seed crystal solution C.

When the aqueous solution A, the aqueous solution B and the seed crystal solution C are supplied to the reaction tank 40, it is preferable to put ion exchange water, pure water, distilled water or the like in the reaction tank 40 in advance.
When the aqueous solution A, the aqueous solution B and the seed crystal solution C are supplied to the reaction tank 40, it is more preferable to control the pH of the mixture in the reaction tank 40 using the aqueous solution B or the other solution D.

The pH of the liquid mixture in the reaction tank 40 is preferably maintained at a predetermined pH of 7 to 9 in view of the tendency of the seed crystals to grow to a transition metal-containing carbonate compound having a large particle diameter in step (b). More preferably, the pH is maintained at a predetermined pH of 7.5 to 8.5.
The range of fluctuation of the pH of the liquid mixture in the reaction vessel 40 at the time of holding at a predetermined pH is preferably ± 0.2 from the viewpoint of sufficiently narrowing the particle size distribution of the transition metal-containing carbonate compound, ± 0.1 Is more preferred.

  The supply amount of the aqueous solution A per unit time may be appropriately set in consideration of the balance between productivity and the circularity and particle size distribution of the transition metal-containing carbonate compound. As the amount of the aqueous solution A supplied per unit time increases, the productivity can be increased. The smaller the amount of the aqueous solution A supplied per unit time, the higher the circularity of the transition metal-containing carbonate compound and the narrower the particle size distribution.

  The supply amount of the aqueous solution B per unit time may be appropriately set so that the pH of the mixture in the reaction tank is in the range of 7 to 9 and the fluctuation range is ± 0.2.

The supply amount of the seed crystal solution C per unit time may be appropriately set according to the target D ₅₀ of the transition metal-containing carbonate compound. When the supply amount per unit time of the seed crystal solution C is increased based on the supply amount per unit time of the aqueous solution A, D ₅₀ of the transition metal-containing carbonate compound decreases and the per unit time of the seed crystal solution C per unit time reducing the supply amount, the transition metal-containing D ₅₀ of the carbonate compound is increased.

Supplying rate at which the feed rate and TaneAkiraeki C per unit time of the aqueous solution A from the viewpoint of reducing the variation of D _50, while obtaining the transition metal-containing carbonate compound of D ₅₀ of interest, a certain It is preferable to keep When the supply amount per unit time of the aqueous solution A and the fluctuation range of the supply amount per unit time of the seed crystal solution C become large, the D ₅₀ of the transition metal-containing carbonate compound will vary. In the case of continuously producing another lot of transition metal-containing carbonate compounds having a different D ₅₀ , either one or both of the supply amount per unit time of the aqueous solution A and the supply amount per unit time of the seed crystal solution C are stepwise It may be changed to

(Step (b))
While carrying out the step (a), the mixed solution containing the aqueous solution A, the aqueous solution B and the seed crystal solution C supplied to the reaction vessel 40 is stirred to grow the transition metal-containing carbonate compound. The transition metal ion and the carbonate ion react to precipitate the transition metal-containing carbonate compound around the seed crystal, and the seed crystal grows into a transition metal-containing carbonate compound having a large particle diameter. The transition metal-containing carbonate compound is preferably grown to a D _{50 of 5} to 15 μm.

  By mixing the aqueous solution A, the aqueous solution B and the seed crystal solution C in the reaction tank 40, the circularity of the transition metal-containing carbonate compound can be made high and the particle size distribution can be narrowed by stirring the mixture. As a drive source of a stirring apparatus, a three-one motor etc. are mentioned, for example. As a stirring blade of a stirring apparatus, stirring blades, such as an anchor type and a propeller type, are mentioned besides the paddle type of the example of illustration.

The temperature of the liquid mixture in the reaction tank 40 is preferably maintained at a predetermined temperature of 20 to 70 ° C. from the viewpoint that the transition metal-containing carbonate compound tends to precipitate, and is maintained at a predetermined temperature of 30 to 50 ° C. Is more preferred.
The fluctuation range of the temperature of the liquid mixture in the reaction vessel 40 at the time of holding at a predetermined temperature is preferably ± 2 ° C., more preferably ± 1 ° C. from the viewpoint of sufficiently narrowing the particle size distribution of the transition metal-containing carbonate compound. preferable.

  When mixing the aqueous solution A, the aqueous solution B and the seed crystal solution C in the reaction tank 40, mixing should be performed under a nitrogen gas atmosphere or an argon gas atmosphere in order to suppress the oxidation of the transition metal-containing carbonate compound. It is preferable to mix under nitrogen gas atmosphere from the viewpoint of cost.

Transition metal-containing carbonate compound _is more preferably grown until _{D 50} is _{6～14Myuemu,} be grown to _{D 50} is 8~11μmm more preferred. The transition metal-containing carbonate compound can be suitably used as a precursor of a positive electrode active material which can sufficiently increase the discharge capacity of a lithium ion secondary battery if D ₅₀ is grown to the above range.

(Step (c))
While performing the step (b), a part of the mixture containing the transition metal-containing carbonate compound in the reaction vessel 40 is continuously or intermittently withdrawn from the reaction vessel 40 without passing through the filter medium.

The extraction of the liquid mixture from the reaction tank 40 is performed, for example, as follows.
-The mixed solution should be the same as the sum of the supplied amounts per unit time of each solution (aqueous solution A, aqueous solution B, seed solution C and other solution D). Remove continuously or intermittently.
-When the volume of the mixture in the reaction vessel 40 exceeds a predetermined threshold, the mixture above the threshold is continuously or intermittently withdrawn.
The liquid mixture overflowing from the reaction tank 40 is discharged as it is.

The extracted transition metal-containing carbonate compound is preferably separated from the mixture by filtration or centrifugation. For filtration or centrifugation, a pressure filter, a vacuum filter, a centrifugal classifier, a filter press, a screw press, a rotary dehydrator, or the like can be used.
The transition metal-containing carbonate compound is preferably washed to remove impurity ions. Examples of the washing method include a method of repeatedly performing pressure filtration and dispersion in distilled water.

After washing, it is preferred to dry the transition metal-containing carbonate compound.
60-200 degreeC is preferable and 80 degreeC-130 degreeC of a drying temperature is more preferable. When the drying temperature is at least the lower limit value, the transition metal-containing carbonate compound can be dried in a short time. If the drying temperature is equal to or less than the upper limit value, oxidation of the transition metal-containing carbonate compound can be suppressed.
The drying time is preferably 1 to 300 hours, more preferably 5 to 120 hours.

(Mechanism of action)
In the method for producing a transition metal-containing carbonate compound of the present invention described above, a seed crystal solution C containing seed crystals is supplied together with an aqueous solution A containing transition metal ions and an aqueous solution B containing carbonate ions, Since the transition metal-containing carbonate compound is precipitated around the seed crystals by reacting ions and carbonate ions, the generation of new nuclei (seed crystals) is suppressed while the supplied seed crystals have a large particle size. Transition metal-containing carbonate compounds can be grown. Therefore, the particle size distribution of the transition metal-containing carbonate compound can be narrowed.
In addition, since a part of the mixed solution is continuously or intermittently withdrawn from the reaction vessel without passing through the filter medium, it is possible to maintain the concentration of the transition metal-containing carbonate compound in the mixed solution in the reaction vessel low. Crystals can be slowly grown to large transition metal-containing carbonate compounds. Therefore, the circularity of the transition metal-containing carbonate compound can be increased, and the particle size distribution can be further narrowed.

(Other forms)
In the method for producing a transition metal-containing carbonate compound of the present invention, (a) supplying the aqueous solution A, the aqueous solution B and the seed crystal solution C continuously or intermittently to the reaction vessel, and (b) While carrying out the step (a), the mixture containing the aqueous solution A, the aqueous solution B and the seed crystal solution C supplied to the reaction vessel is stirred, and a transition metal containing either or both of Ni and Co and Mn. A step of growing the contained carbonate compound, and (c) carrying out the step (b), continuously or intermittently part of the mixture containing the transition metal-containing carbonate compound in the reaction vessel from the reaction vessel The method is not limited to the manufacturing method using the apparatus of the illustrated example as long as the method includes the steps of

<Transition metal-containing carbonate compound>
The transition metal-containing carbonate compound of the present invention is represented by Ni _x Co _y Mn _z M _(1-x-y-z) CO ₃ , and the value at a 50% cumulative frequency of circularity is 0.970 or more. , D ₉₀ / D ₁₀ are 2 to 6.

  x represents the molar ratio of Ni contained in the transition metal-containing carbonate compound. x is 0.15 to 0.5, preferably 0.15 to 0.45, and more preferably 0.2 to 0.4. If x is in the above range, it is possible to obtain a positive electrode active material that can increase the discharge capacity and charge / discharge efficiency of the lithium ion secondary battery.

  y represents the molar ratio of Co contained in the transition metal-containing carbonate compound. y is 0 to 0.33, preferably 0 to 0.2, and more preferably 0 to 0.15. If y is in the above range, it is possible to obtain a positive electrode active material that can increase the discharge capacity and charge / discharge efficiency of the lithium ion secondary battery.

z represents the molar ratio of Mn contained in the transition metal-containing carbonate compound. z is 0.33 to 0.85, preferably 0.5 to 0.8, and more preferably 0.5 to 0.7. If z is in the above range, it is possible to obtain a positive electrode active material that can increase the discharge capacity and charge / discharge efficiency of the lithium ion secondary battery.
The total amount (x + y + z) of x, y and z does not exceed 1.

  The transition metal-containing carbonate compound may optionally contain other metal element M. Examples of other metal elements M include Mg, Ca, Ba, Sr, Al, Cr, Fe, Ti, Zr, Nb, Mo, Ta, W, Ce, La and the like. Mg, Al, Cr, Fe, Ti or Zr is preferable from the viewpoint that a positive electrode active material capable of increasing the discharge capacity of the lithium ion secondary battery is easily obtained.

  The value at the 50% cumulative frequency of circularity of the transition metal-containing carbonate compound is 0.970 or more, preferably 0.972 or more, and more preferably 0.975 or more. If the value at the 50% cumulative frequency of the degree of circularity is equal to or more than the lower limit value, a positive electrode active material containing a lithium-containing composite oxide having a high degree of circularity can be obtained. As a result, the density of the positive electrode active material in the positive electrode becomes high, and the discharge capacity of the lithium ion secondary battery per unit volume of the positive electrode active material becomes sufficiently high. The upper limit of the 50% cumulative frequency of circularity of the transition metal-containing carbonate compound is 1.

D ₉₀ / D ₁₀ of the transition metal-containing carbonate compound is 2 to 6, preferably 2 to 5, and more preferably 2.5 to 3.5. If D _{90 /} D ₁₀ is more than the above lower limit, it is easy to manufacture the transition metal-containing carbonate compound. If D ₉₀ / D ₁₀ is equal to or less than the upper limit value, the particle size distribution of the transition metal-containing carbonate compound is narrow, so a lithium-containing composite oxide having a narrow particle size distribution can be obtained. Since the positive electrode active material containing a lithium-containing composite oxide having a narrow particle size distribution has few coarse particles, the coatability at the time of applying the slurry containing the positive electrode active material to the positive electrode current collector is improved. In addition, after the slurry containing the positive electrode active material is applied to the positive electrode current collector, the frequency at which coarse particles are broken when rolling is reduced, and the deterioration of the cycle characteristics of the lithium ion secondary battery can be suppressed.

Transition metal-containing _{D 50} of the carbonate compound is preferably 5 to 15 [mu] m, more preferably 6～14Myuemu, more preferably 8～11Myuemu. If D ₅₀ of the transition metal-containing carbonate compound is within the above range, a positive electrode active material capable of sufficiently increasing the discharge capacity of the lithium ion secondary battery can be obtained.

The specific surface area of the transition metal-containing carbonate compound is preferably ^{50~300m 2 / g, 100~250m 2 /} g is more preferable. If the specific surface area of the transition metal-containing carbonate compound is within the above range, the specific surface area of the lithium-containing composite oxide can be easily controlled within the preferable range. The specific surface area of the transition metal-containing carbonate compound is a value measured after drying the transition metal-containing carbonate compound at 120 ° C. for 15 hours.

1-2 g / cm < ³ > is preferable and, as for the tap density of a transition metal containing carbonate compound, 1.2-1.8 g / cm < ³ > is more preferable. If the tap density of the transition metal-containing carbonate compound is within the above range, the tap density of the lithium-containing composite oxide can be easily controlled within the preferable range.

  The transition metal-containing carbonate compound of the present invention can be obtained, for example, by the method for producing a transition metal-containing carbonate compound described above.

(Mechanism of action)
In the transition metal-containing carbonate compound of the present invention described above, the value at the 50% cumulative frequency of the circularity is 0.970 or more, and D ₉₀ / D ₁₀ is 2 to 6, so that it is circular. Degree of particle size distribution is narrow. In addition, since the degree of circularity is high and the particle size distribution is narrow and the composition has a specific composition, it is possible to obtain a positive electrode active material capable of making the discharge capacity and cycle characteristics of the lithium ion secondary battery excellent.

<Method of manufacturing positive electrode active material>
The method for producing a positive electrode active material of the present invention is a method for producing a positive electrode active material containing a lithium-containing composite oxide, and comprises the following step (d), the following step (e) and the following step (f).
(D) A transition metal-containing carbonate compound obtained by the method for producing a transition metal-containing carbonate compound of the present invention, or a mixture obtained by mixing the transition metal-containing carbonate compound of the present invention and a lithium compound Step of firing to obtain a lithium-containing composite oxide.
(E) A step of washing the lithium-containing composite oxide as required.
(F) optionally forming a coating on the surface of the lithium-containing composite oxide.

(Step (d))
For example, the transition metal-containing carbonate compound obtained in step (c) and the lithium compound are mixed and fired. Thereby, lithium containing complex oxide is obtained.
The ratio of Li, Ni, Co, Mn and M contained in the lithium-containing composite oxide is the same as the ratio of Li, Ni, Co, Mn and M contained in the mixture of the transition metal-containing carbonate compound and the lithium compound. is there.

The lithium compound is preferably at least one selected from the group consisting of lithium carbonate, lithium hydroxide and lithium nitrate, and lithium carbonate is more preferable from the viewpoint of easy handling.
Examples of the method of mixing the transition metal-containing carbonate compound and the lithium compound include a method using a rocking mixer, a Nauta mixer, a spiral mixer, a cutter mill, a V mixer, and the like.

As a baking apparatus, an electric furnace, a continuous baking furnace, a rotary kiln, etc. are mentioned.
Since the transition metal-containing carbonate compound is oxidized at the time of firing, the firing is preferably performed in the air, and is particularly preferably performed while supplying air.
The air supply rate is preferably 10 to 200 mL / min, and more preferably 40 to 150 mL / min, per 1 L of internal volume of the furnace.
By supplying air at the time of firing, the transition metal element in the transition metal-containing carbonate compound is sufficiently oxidized, and a positive electrode active material including a lithium-containing composite oxide having high crystallinity and an intended crystal phase is obtained. can get.

  The firing may be one-step firing or may be two-step firing in which main firing is performed after temporary firing. Two-stage firing is preferable from the viewpoint that Li easily diffuses uniformly into the lithium-containing composite oxide.

The firing temperature in the case of one-stage firing is 500 to 1000 ° C., preferably 600 to 1000 ° C., and particularly preferably 800 to 950 ° C.
400-700 degreeC is preferable and, as for the temperature of the temporary baking in the case of 2 step | paragraph baking, 500-650 degreeC is more preferable.
700-1000 degreeC is preferable and, as for the temperature of this baking in the case of two-step baking, 800-950 degreeC is more preferable.
If the calcination temperature is within the above range, a lithium-containing composite oxide having high crystallinity can be obtained.

The firing time is preferably 4 to 40 hours, more preferably 4 to 20 hours.
If the firing time is within the above range, a lithium-containing composite oxide with high crystallinity can be obtained.

(Step (e))
The lithium-containing composite oxide may be washed with water for the purpose of removing impurities such as Na.
As a washing | cleaning method, the method of mixing and stirring lithium containing complex oxide and water is mentioned, for example. The stirring time is preferably 0.5 to 72 hours.
After washing the lithium-containing composite oxide, it is preferable to separate the lithium-containing composite oxide and water by filtration and to dry the lithium-containing composite oxide. The drying temperature is preferably 50 to 110 ° C. The drying time is preferably 1 to 24 hours.
The dried lithium-containing composite oxide may be further calcined. The firing temperature is preferably 200 to 600 ° C. The firing time is preferably 0.5 to 12 hours.

(Step (f))
Examples of the method for forming a coating on the surface of the lithium-containing composite oxide include a powder mixing method, a gas phase method, a spray coating method, an immersion method and the like. Hereinafter, the case where the coating is a compound of Al will be described.
The powder mixing method is a method of heating after mixing the lithium-containing composite oxide and the compound of Al. The gas phase method is a method of vaporizing an organic compound containing Al such as aluminum ethoxide, aluminum isopropoxide, aluminum acetylacetonate, etc., and bringing the organic compound into contact with the surface of the lithium-containing composite oxide for reaction. . The spray coating method is a method in which a lithium-containing composite oxide is sprayed after being sprayed with a solution containing Al, and then heated.
In addition, an Al water-soluble compound (aluminum acetate, aluminum oxalate, aluminum citrate, aluminum lactate, basic aluminum lactate, aluminum nitrate, etc.) for forming a compound of Al is dissolved in a lithium-containing composite oxide in a solvent. After contacting with the aqueous solution, the solvent may be removed by heating to form a coating containing the compound of Al on the surface of the lithium-containing composite oxide.

The lithium-containing composite oxide can be prepared by using Li _α Ni _x Co _y Mn _z M _(1-x-y-z) O _β (wherein 1.1 ≦ α ≦ 1.7, 0.15 ≦ x ≦ 0.5). , 0 ≦ y ≦ 0.33, 0.33 ≦ z ≦ 0.85, x + y + z = 1. β is an oxygen element necessary to satisfy the valences of Li, Ni, Co, Mn and M ( What is represented by the number of moles of O) is preferred.

  α represents a molar ratio of Li contained in the lithium-containing composite oxide. 1.1-1.5 are preferable and 1.1-1.45 of alpha are more preferable. If α is equal to or more than the lower limit value, the discharge capacity of the lithium ion secondary battery having the positive electrode active material can be increased. If alpha is below the said upper limit, the amount of free lithium on the surface of lithium containing complex oxide can be reduced. If the amount of free lithium is large, the charge / discharge efficiency or rate characteristics of the lithium ion secondary battery may be degraded, or decomposition of the electrolyte may be promoted to cause gas generation of decomposition products.

x shows the molar ratio of Ni contained in lithium containing complex oxide.
y represents the molar ratio of Co contained in the lithium-containing composite oxide.
z shows the molar ratio of Mn contained in lithium containing complex oxide.
The ranges of x, y and z are respectively the same as the ranges of x, y and z in the above-mentioned transition metal-containing carbonate compound, and the preferred ranges are also the same.
The total amount (x + y + z) of x, y and z does not exceed 1.

The lithium-containing composite oxide may contain other metal element M as necessary. The other metal element M is the same as M contained in the above-mentioned transition metal-containing carbonate compound, and preferred metal elements are also the same.
β is the number of moles of oxygen element (O) necessary to satisfy the valences of Li, Ni, Co, Mn and M.

The lithium-containing composite oxide has a layered rock salt type crystal structure of a space group C2 / m and a layered rock salt type crystal structure of a space group R-3 m. The crystal structure of the space group C2 / m is also referred to as lithium-rich phase. Examples of the compound having a crystal structure of the space group _{C2 / m, Li (Li 1/3} Mn 2/3) O 2 and the like. Examples of the compound having a crystal structure of the space group R-3m, LiMeO ₂ (although, Me is, Ni, Co, at least one element selected from Mn.) And the like. It can be confirmed by X-ray diffraction measurement that the lithium-containing composite oxide has these crystal structures.

  The value at the 50% cumulative frequency of the circularity of the positive electrode active material obtained by the above method is preferably 0.970 or more, more preferably 0.972 or more, and still more preferably 0.975 or more. If the value at the 50% cumulative frequency of the degree of circularity is equal to or more than the lower limit value, a positive electrode active material containing a lithium-containing composite oxide having a high degree of circularity can be obtained. As a result, the density of the positive electrode active material in the positive electrode becomes high, and the discharge capacity of the lithium ion secondary battery per unit volume of the positive electrode active material becomes sufficiently high. The upper limit of the 50% cumulative frequency of circularity of the lithium-containing composite oxide is 1.

_D 90 _{/ D 10} of the positive electrode active material obtained by the above method, 2 to 6, more preferably 2 to 5, more preferably 2.5 to 3.5. If D ₉₀ / D ₁₀ is at least the above lower limit value, the production of the lithium-containing composite oxide is easy. If D _{90 /} D ₁₀ is less than the upper limit, it is possible to size distribution to obtain a positive electrode active material comprising a narrow lithium-containing composite oxide. Since the positive electrode active material has few coarse particles, the coatability at the time of applying the slurry containing the positive electrode active material on the positive electrode current collector is improved. In addition, after the slurry containing the positive electrode active material is applied to the positive electrode current collector, the frequency at which coarse particles are broken when rolling is reduced, and the deterioration of the cycle characteristics of the lithium ion secondary battery can be suppressed.

_{D 50} of the positive electrode active material obtained by the above method is preferably from 5 to 15 [mu] m, more preferably 6～14Myuemu, more preferably 8～11Myuemu. If D ₅₀ of the positive electrode active material within the range, sufficiently high discharge capacity of the lithium ion secondary battery.

0.1-10 m < ² > / g is preferable, as for the specific surface area of the positive electrode active material obtained by the said method, 0.5-7 m < ² > / g is more preferable, and 0.5-5 m < ² > / g is especially preferable. If the specific surface area of the positive electrode active material is within the above range, both the discharge capacity and the cycle characteristics of the lithium ion secondary battery can be sufficiently high.

(Mechanism of action)
In the method of manufacturing the positive electrode active material of the present invention described above, since the transition metal-containing carbonate compound having a high degree of circularity and a narrow particle size distribution is used as the precursor, the degree of circularity is high and the particle size distribution is A positive electrode active material containing a narrow lithium-containing composite oxide can be produced.

<Positive electrode for lithium ion secondary battery>
The positive electrode for a lithium ion secondary battery of the present invention (hereinafter referred to as the present positive electrode) contains the positive electrode active material obtained by the method for producing a positive electrode active material of the present invention. Specifically, a positive electrode active material layer containing a positive electrode active material, a conductive material, and a binder is formed on a positive electrode current collector.

Examples of the conductive material include carbon black (acetylene black, ketjen black and the like), graphite, vapor grown carbon fiber, carbon nanotube and the like.
As the binder, fluorine resin (polyvinylidene fluoride, polytetrafluoroethylene, etc.), polyolefin (polyethylene, polypropylene, etc.), polymer or copolymer having unsaturated bond (styrene / butadiene rubber, isoprene rubber, butadiene rubber, etc.) And acrylic acid polymers or copolymers (acrylic acid copolymers, methacrylic acid copolymers, etc.) and the like.
Examples of the positive electrode current collector include aluminum foil and stainless steel foil.

The present positive electrode can be produced, for example, by the following method.
The positive electrode active material, the conductive material and the binder are dissolved or dispersed in a medium to obtain a slurry. The obtained slurry is applied to a positive electrode current collector, and the medium is removed by drying or the like to form a positive electrode active material layer. As needed, after forming a positive electrode active material layer, you may roll with a roll press etc. Thus, the present positive electrode is obtained.
Alternatively, a kneaded material is obtained by kneading the positive electrode active material, the conductive material and the binder with a medium. The obtained kneaded product is rolled to a positive electrode current collector to obtain the present positive electrode.

(Mechanism of action)
In the present positive electrode described above, since the positive electrode active material including the lithium-containing composite oxide having a high degree of circularity is included, the density of the positive electrode active material in the positive electrode becomes high, and lithium ions per unit volume of the positive electrode active material The discharge capacity of the secondary battery is sufficiently high. In addition, since the positive electrode active material containing a lithium-containing composite oxide having a narrow particle size distribution is included, coarse particles are reduced, and the coatability at the time of applying the slurry containing the positive electrode active material to the positive electrode current collector is improved. In addition, after the slurry containing the positive electrode active material is applied to the positive electrode current collector, the frequency at which coarse particles are broken when rolling is reduced, and the deterioration of the cycle characteristics of the lithium ion secondary battery can be suppressed.

<Lithium ion secondary battery>
The lithium ion secondary battery (hereinafter referred to as the present battery) of the present invention has the present positive electrode. Specifically, the positive electrode, the negative electrode, and the non-aqueous electrolyte are included.

(Negative electrode)
The negative electrode contains a negative electrode active material. Specifically, a negative electrode active material layer and, if necessary, a negative electrode active material layer containing a conductive material and a binder are formed on a negative electrode current collector.

  The negative electrode active material may be any material that can occlude and release lithium ions at a relatively low potential. As the negative electrode active material, lithium metal, lithium alloy, lithium compound, carbon material, oxide mainly composed of metal of periodic table group 14, oxide mainly composed of metal of periodic table group 15, carbon compound, silicon carbide compound And silicon oxide compounds, titanium sulfide, and boron carbide compounds.

  As a carbon material of the negative electrode active material, non-graphitizable carbon, artificial graphite, natural graphite, pyrolytic carbons, cokes (pitch coke, needle coke, petroleum coke, etc.), graphites, glassy carbons, organic high materials A molecular compound fired body (phenol resin, furan resin, etc. fired and carbonized at an appropriate temperature), carbon fiber, activated carbon, carbon blacks, etc. may be mentioned.

As a metal of periodic table 14 group used for a negative electrode active material, Si and Sn are mentioned, and Si is preferable.
Other negative electrode active materials include oxides such as iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, titanium oxide and tin oxide, and other nitrides.

As the conductive material of the negative electrode and the binder, the same materials as those of the positive electrode can be used.
Examples of the negative electrode current collector include metal foils such as nickel foil and copper foil.

The negative electrode can be produced, for example, by the following method.
The negative electrode active material, the conductive material and the binder are dissolved or dispersed in a medium to obtain a slurry. The medium is removed by coating the obtained slurry on a negative electrode current collector, drying, pressing or the like to obtain a negative electrode.

(Non-aqueous electrolyte)
Examples of the non-aqueous electrolyte include a non-aqueous electrolytic solution in which an electrolyte salt is dissolved in an organic solvent; an inorganic solid electrolyte; and a solid or gel polymer electrolyte in which an electrolytic salt is mixed or dissolved.

  As an organic solvent, what is well-known as an organic solvent for non-aqueous electrolytes is mentioned. Specifically, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, acetate, butyric acid Ester, propionic acid ester and the like can be mentioned. From the viewpoint of voltage stability, cyclic carbonates (such as propylene carbonate) and linear carbonates (such as dimethyl carbonate and diethyl carbonate) are preferable. An organic solvent may be used individually by 1 type, and may mix and use 2 or more types.

The inorganic solid electrolyte may be a material having lithium ion conductivity.
Examples of the inorganic solid electrolyte include lithium nitride and lithium iodide.

  Examples of the polymer used for the solid polymer electrolyte include ether-based polymer compounds (polyethylene oxide, crosslinked products thereof, etc.), polymethacrylate ester-based polymer compounds, acrylate-based polymer compounds and the like. The polymer compounds may be used alone or in combination of two or more.

As polymers used for gel-like polymer electrolytes, fluorine-based polymer compounds (polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, etc.), polyacrylonitrile, acrylonitrile copolymer, ether polymer compounds ( Polyethylene oxide, its crosslinked body, etc. are mentioned. Examples of the monomer copolymerized with the copolymer include polypropylene oxide, methyl methacrylate, butyl methacrylate, methyl acrylate, butyl acrylate and the like.
As the polymer compound, a fluorine-based polymer compound is preferable from the viewpoint of the stability to the oxidation-reduction reaction.

The electrolyte salt may be any one as long as it is used in a lithium ion secondary battery. Examples of the electrolyte salt include LiClO ₄ , LiPF ₆ , LiBF ₄ , CH ₃ SO ₃ Li and the like.

  A separator may be interposed between the positive electrode and the negative electrode to prevent a short circuit. A porous membrane is mentioned as a separator. The non-aqueous electrolyte is used by impregnating the porous membrane. Further, a porous membrane impregnated with a non-aqueous electrolytic solution and gelled may be used as a gel electrolyte.

  Examples of the material of the battery outer package include nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, a resin material, a film material and the like.

  The shape of the lithium ion secondary battery may, for example, be a coin, a sheet (film), a fold, a winding type, a bottomed cylindrical, a button, or the like, which can be appropriately selected according to the application.

(Mechanism of action)
In the present battery described above, since the present positive electrode is provided, discharge capacity and cycle characteristics are excellent.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.
Examples 2-2, 2-3 and 3-6 are examples, and examples 1 and 2-1 are comparative examples.

(Particle size)
A seed crystal or transition metal-containing carbonate compound is sufficiently dispersed in water by ultrasonic treatment, and measurement is performed using a laser diffraction / scattering particle size distribution measuring apparatus (MT-3300EX, manufactured by Nikkiso Co., Ltd.), and the frequency distribution and cumulative volume A volume-based particle size distribution was obtained by obtaining a distribution curve. D ₁₀ , D ₅₀ and D ₉₀ were determined from the obtained cumulative volume distribution curve.

(Tap density)
The tap density (unit: g / cm ³ ) of the transition metal-containing carbonate compound was calculated from the following equation. V in the following formula is the volume (unit: cm ³ ) of the sample after tapping, weigh the sample (transition metal-containing carbonate compound) in a resin container (volume: 20 cm ³ ) with a scale, and tap the container The sample was attached to an apparatus (KYT-4000K, manufactured by Seishin Enterprise Co., Ltd.), tapped 700 times, and the value of the volume of the sample in the container was read on the scale of the container. In the following formula, m is the mass of the sample (unit: g), which is the mass of the sample added to the resinous container.
ρ _t = m / V

(Specific surface area)
The specific surface area of the transition metal-containing carbonate compound was calculated by a nitrogen adsorption BET method using a specific surface area measurement device (manufactured by Mountech Co., HM model-1208). Degassing was performed at 200 ° C. for 20 minutes.

(Roundness)
The roundness specific surface area of the transition metal-containing carbonate compound was measured using a flow type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation).
For the measured circularity of all particles, create a distribution curve whose horizontal axis is circularity (0 to 1) and whose vertical axis is cumulative frequency of circularity (0 to 100%), in the distribution curve The circularity value was read when the cumulative frequency was 50%.

(Composition analysis)
The compositional analysis of the transition metal-containing carbonate compound was performed using a plasma emission analyzer (SPS3100H, manufactured by SII Nano Technology Inc.).

(Example 1)
Preparation of aqueous solution:
The molar ratio of Ni, Co and Mn in the nickel (II) sulfate, hexahydrate, cobalt (II) sulfate, heptahydrate, manganese (II) sulfate, pentahydrate is the ratio shown in Table 1 Thus, an aqueous solution A was prepared by dissolving in distilled water such that the total concentration of Ni, Co and Mn was 1.5 mol / kg.
An aqueous solution B was prepared by dissolving sodium carbonate in distilled water so as to be 1.5 mol / kg.

Preparation of Transition Metal-Containing Carbonate Compounds:
The particle growth apparatus 3 shown in FIG. 4 was prepared.
A 2-liter baffled glass reaction vessel 40 was charged with 1.9 liters of distilled water. The transition metal-containing carbonate compound was produced by maintaining the liquid in the reaction tank 40 at 30 ± 1 ° C. with a hot water bath.
Aqueous solution A was continuously added at 5 g / min for 25 hours while stirring the solution in the reaction vessel 40 with a two-stage inclined paddle type stirring blade 42.
The initial pH of the mixture in the reaction tank 40 is set to 8.5, and during the addition of the aqueous solution A, the aqueous solution B is added to maintain the pH in the reaction tank 40 at 8.5 ± 0.1, and Ni, Co And a transition metal-containing carbonate compound containing Mn were precipitated.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the reaction vessel 40 so that the precipitated transition metal-containing carbonate compound was not oxidized. A concentration method was adopted as the precipitation method, and during the reaction, a liquid not containing the transition metal-containing carbonate compound was continuously withdrawn using a filter cloth so that the liquid volume in the reaction tank 40 did not exceed 2 L. . Twenty-five hours after the addition of the aqueous solution A was started, the entire amount of the mixture in the reaction vessel 40 was recovered.
In order to remove impurity ions from the obtained transition metal-containing carbonate compound, pressure filtration and dispersion in distilled water were repeated to wash the transition metal-containing carbonate compound. Washing was terminated when the conductivity of the filtrate was less than 50 mS / m, and the transition metal-containing carbonate compound was dried at 120 ° C. for 15 hours. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

(Example 2)
Preparation of aqueous solution:
The molar ratio of Ni, Co and Mn in the nickel (II) sulfate, hexahydrate, cobalt (II) sulfate, heptahydrate, manganese (II) sulfate, pentahydrate is the ratio shown in Table 1 Thus, an aqueous solution A was prepared by dissolving in distilled water such that the total concentration of Ni, Co and Mn was 1.5 mol / kg.
An aqueous solution B was prepared by dissolving sodium carbonate in distilled water so as to be 1.5 mol / kg.

Preparation of seed solution:
A seed crystal preparation apparatus 1a shown in FIG. 1 was prepared.
Into 2 L of baffled glass seed solution preparation tank 10 was added 1.9 L of distilled water. The production of the seed crystal was carried out by maintaining the liquid in the seed crystal preparation tank 10 at 30 ± 1 ° C. with a water bath.
While stirring the solution in the seed crystal preparation tank 10 with a two-stage inclined paddle type stirring blade 12 and irradiating the seed crystal preparation tank 10 with ultrasonic waves, the aqueous solution A is continuously applied at 5 g / min for 14 hours Added to
The initial pH of the mixture in the seed crystal preparation tank 10 is set to 8.0, and during the addition of the aqueous solution A, the aqueous solution B is maintained so as to maintain the pH in the seed crystal preparation tank 10 at 8.0 ± 0.1. Then, a carbonate compound (seed crystal) containing Ni, Co and Mn was precipitated.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the seed crystal preparation tank 10 so that the precipitated seed crystals were not oxidized. A concentration method is adopted as a precipitation method, and during the reaction, a portion of the mixture in the seed crystal preparation tank 10 is circulated to the mixture circulation line 20, and the liquid volume in the seed crystal preparation tank 10 exceeds 2 liters. In order to prevent this, the MF membrane module 24 was used to continuously withdraw the liquid containing no seed crystal. Fourteen hours after the start of the addition of the aqueous solution A, the whole of the mixture in the seed crystal preparation tank 10 was recovered to obtain a seed crystal C. The results and the solid content concentration of the obtained seed crystal solution C are shown in Table 1.

Example 2-1:
The particle growth apparatus 3 shown in FIG. 4 was prepared.
A 2-liter baffled glass reaction vessel 40 was charged with 1.9 liters of distilled water. The transition metal-containing carbonate compound was produced by maintaining the liquid in the reaction tank 40 at 30 ± 1 ° C. with a hot water bath.
Aqueous solution A was continuously added at 5 g / min for 20 hours while stirring the solution in the reaction vessel 40 with a two-stage inclined paddle type stirring blade 42.
The initial pH of the mixture in the reaction tank 40 is set to 8.0, and during the addition of the aqueous solution A, the aqueous solution B is added to maintain the pH in the reaction tank 40 at 8.0 ± 0.1, and Ni, Co And a transition metal-containing carbonate compound containing Mn were precipitated.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the reaction vessel 40 so that the precipitated transition metal-containing carbonate compound was not oxidized. The overflow method was employed as the precipitation method, and the liquid mixture was drawn from the liquid mixture extraction line 50 so that the liquid volume in the reaction tank did not exceed 2 L during the reaction.
The transition metal-containing carbonate compound which overflowed between 6 and 20 hours from the start of the first addition of the aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

Example 2-2:
Forty hours after the start of the first addition of aqueous solution A of Example 2-1, aqueous solution A was continuously added at 5 g / min and seed crystal solution C at 5 g / hour for 21 hours.
During the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added to keep the pH in the reaction vessel 40 at 8.0 ± 0.1, and the seed crystals are grown to contain Ni, Co and Mn. A transition metal-containing carbonate compound was formed.
The transition metal-containing carbonate compound which overflowed during 55 to 64 hours from the start of the first addition of the aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

Example 2-3:
After Example 2-2, 61 hours after the start of the first addition of aqueous solution A of Example 2-1, continuous addition of aqueous solution A at 5 g / min and seed crystal solution C at 15 g / hour for 21 hours did.
During the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added to keep the pH in the reaction vessel 40 at 8.0 ± 0.1, and the seed crystals are grown to contain Ni, Co and Mn. A transition metal-containing carbonate compound was formed.
The transition metal-containing carbonate compound overflowed between 70 and 82 hours from the start of the first addition of aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

(Example 3)
Preparation of aqueous solution:
The nickel (II) sulfate hexahydrate and the manganese (II) sulfate pentahydrate are mixed so that the molar ratio of Ni and Mn is as shown in Table 1, and the total concentration of Ni and Mn is 1. An aqueous solution A was prepared by dissolving in distilled water so as to be 5 mol / kg.
An aqueous solution B was prepared by dissolving sodium carbonate in distilled water so as to be 1.5 mol / kg.

Preparation of seed solution:
A seed crystal preparation device 1b shown in FIG. 2 was prepared.
Into 2 L of baffled glass seed solution preparation tank 10 was added 1.9 L of distilled water. The production of the seed crystal was carried out by maintaining the liquid in the seed crystal preparation tank 10 at 30 ± 1 ° C. with a water bath.
While stirring the solution in the seed crystal preparation tank 10 at 7500 rpm using the shaft generator 32, the aqueous solution A was continuously added at 5 g / min for 22 hours.
The initial pH of the mixture in the seed crystal preparation tank 10 is set to 8.0, and during the addition of the aqueous solution A, the aqueous solution B is maintained so as to maintain the pH in the seed crystal preparation tank 10 at 8.0 ± 0.1. It was added to precipitate a carbonate compound (seed crystal) containing Ni and Mn.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the seed crystal preparation tank 10 so that the precipitated seed crystals were not oxidized. A concentration method is adopted as a precipitation method, and during the reaction, a portion of the mixture in the seed crystal preparation tank 10 is circulated to the mixture circulation line 20, and the liquid volume in the seed crystal preparation tank 10 exceeds 2 liters. In order to prevent this, the MF membrane module 24 was used to continuously withdraw the liquid containing no seed crystal. Fourteen hours after the start of the first addition of the aqueous solution A, 1191.4 g of the mixture in the seed crystal preparation tank 10 was withdrawn from the mixture discharge line.

Twenty-two hours after the start of the first addition of the aqueous solution A, the rotation number of the shaft generator 32 was changed to 5000 rpm, and then the aqueous solution A was continuously added at 5 g / min for 26 hours.
During the addition of the aqueous solution A, the aqueous solution B was added so as to keep the pH in the seed crystal preparation tank 10 at 8.0 ± 0.1, to precipitate a carbonate compound (seed crystal) containing Ni and Mn. .
During the reaction, a portion of the mixture in the seed crystal preparation tank 10 is circulated to the mixture circulation line 20, and the MF membrane module 24 is used so that the liquid volume in the seed crystal preparation tank 10 does not exceed 2 L. The liquid which did not contain seed crystals was continuously withdrawn. After 34 hours from the start of the first addition of the aqueous solution A, 1997.4 g of the mixture in the seed crystal preparation tank 10 was withdrawn from the mixture discharge line. Furthermore, 48 hours after the start of the first addition of aqueous solution A, the whole of the mixture in seed liquid crystal preparation tank 10 was recovered, and the one after 48 hours from the start of the initial addition of aqueous solution A was used as seed crystal solution C . The results and the solid content concentration of the obtained seed crystal solution C are shown in Table 1.

Example 3-1:
The particle growth apparatus 3 shown in FIG. 4 was prepared.
A 2-liter baffled glass reaction vessel 40 was charged with 1.9 liters of distilled water. The transition metal-containing carbonate compound was produced by maintaining the liquid in the reaction tank 40 at 30 ± 1 ° C. with a hot water bath.
While stirring the solution in the reaction vessel 40 with a two-stage inclined paddle type stirring blade 42, aqueous solution A was continuously added at 5 g / min and seed crystal solution C at 5 g / h for 44 hours.
The initial pH of the mixture in the reaction vessel 40 is set to 8.0, and during the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added so as to maintain the pH in the reaction vessel 40 at 8.0 ± 0.1. Seed crystals were grown to form transition metal-containing carbonate compounds including Ni and Mn.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the reaction vessel 40 so that the precipitated transition metal-containing carbonate compound was not oxidized. The overflow method was employed as the precipitation method, and the liquid mixture was drawn from the liquid mixture extraction line 50 so that the liquid volume in the reaction tank did not exceed 2 L during the reaction.
The transition metal-containing carbonate compound which overflowed between 27 and 45 hours from the start of the first addition of aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

Example 3-2:
From 44 hours after the start of the first addition of the aqueous solution A of Example 3-1, the aqueous solution A was continuously added at 5 g / min and the seed crystal solution C at 15 g / hour for 43 hours.
During the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added so as to keep the pH in the reaction vessel 40 at 8.0 ± 0.1, and the seed crystals are grown, and the transition metal containing Ni and Mn is added. Contained carbonate compounds were formed.
The transition metal-containing carbonate compound which overflowed between 66 and 87 hours from the start of the first addition of aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

Example 3-3:
After Example 3-2, 87 hours after the start of the first addition of aqueous solution A of Example 3-1, continuous addition of aqueous solution A at 5 g / min and seed crystal solution C at 25 g / hour for 30 hours did.
During the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added so as to keep the pH in the reaction vessel 40 at 8.0 ± 0.1, and the seed crystals are grown, and the transition metal containing Ni and Mn is added. Contained carbonate compounds were formed.
The transition metal-containing carbonate compound which overflowed between 99 to 117 hours from the start of the first addition of the aqueous solution A and the transition metal-containing carbonate compound in the reaction vessel 40 were recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

(Example 4)
Preparation of aqueous solution:
An aqueous solution A and an aqueous solution B were prepared in the same manner as in Example 3.

Preparation of seed solution:
A seed crystal preparation device 1c shown in FIG. 3 was prepared.
Into 2 L of baffled glass seed solution preparation tank 10 was added 1.9 L of distilled water. The production of the seed crystal was carried out by maintaining the liquid in the seed crystal preparation tank 10 at 30 ± 1 ° C. with a water bath.
Aqueous solution A was continuously added at 5 g / min for 69 hours while stirring the solution in the seed crystal preparation tank 10 with a two-stage inclined paddle type stirring blade 12.
The initial pH of the mixture in the seed crystal preparation tank 10 is set to 8.0, and during the addition of the aqueous solution A, the aqueous solution B is maintained so as to maintain the pH in the seed crystal preparation tank 10 at 8.0 ± 0.1. It was added to precipitate a carbonate compound (seed crystal) containing Ni and Mn.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the seed crystal preparation tank 10 so that the precipitated seed crystals were not oxidized. During the reaction, part of the mixture in the seed crystal preparation tank 10 was circulated through the mixture circulation line 20 and treated with the circulation ultrasonic homogenizer 34. The pump 28 was not operated, and the liquid was not withdrawn from the liquid mixture circulating in the liquid mixture circulation line 20. The overflow method was employed as the precipitation method, and the liquid mixture was drawn from the liquid mixture extraction line 36 so that the liquid volume of the seed crystal preparation tank 10 did not exceed 2 L during the reaction.
A mixed solution which overflowed between 39 and 69 hours from the start of the first addition of the aqueous solution A was recovered, and a seed crystal solution C was obtained. The results and the solid content concentration of the obtained seed crystal solution C are shown in Table 1.

Preparation of Transition Metal-Containing Carbonate Compounds:
The particle growth apparatus 3 shown in FIG. 4 was prepared.
A 2-liter baffled glass reaction vessel 40 was charged with 1.9 liters of distilled water. The transition metal-containing carbonate compound was produced by maintaining the liquid in the reaction tank 40 at 30 ± 1 ° C. with a hot water bath.
While stirring the solution in the reaction vessel 40 with a two-stage inclined paddle type stirring blade 42, the aqueous solution A was continuously added at 5 g / min and the seed crystal solution C at 66 g / h for 42 hours.
The initial pH of the mixture in the reaction vessel 40 is set to 8.0, and during the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added so as to maintain the pH in the reaction vessel 40 at 8.0 ± 0.1. Seed crystals were grown to form transition metal-containing carbonate compounds including Ni and Mn.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the reaction vessel 40 so that the precipitated transition metal-containing carbonate compound was not oxidized. In addition, the overflow method was employed as a precipitation method, and during the reaction, the liquid mixture was drawn from the liquid mixture extraction line 50 so that the liquid volume in the reaction tank did not exceed 2 liters.
The transition metal-containing carbonate compound overflowed between 21 and 42 hours from the start of the first addition of the aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

(Example 5)
Preparation of aqueous solution:
The nickel (II) sulfate hexahydrate and the manganese (II) sulfate pentahydrate are mixed so that the molar ratio of Ni and Mn is as shown in Table 1, and the total concentration of Ni and Mn is 1. An aqueous solution A was prepared by dissolving in distilled water so as to be 5 mol / kg.
An aqueous solution B was prepared by dissolving sodium carbonate in distilled water so as to be 1.5 mol / kg.

Preparation of seed solution:
A seed crystal preparation device 1c shown in FIG. 3 was prepared.
Into 2 L of baffled glass seed solution preparation tank 10 was added 1.9 L of distilled water. The production of the seed crystal was carried out by maintaining the liquid in the seed crystal preparation tank 10 at 30 ± 1 ° C. with a water bath.
Aqueous solution A was continuously added at 5 g / min for 69 hours while stirring the solution in the seed crystal preparation tank 10 with a two-stage inclined paddle type stirring blade 12.
The initial pH of the mixture in the seed crystal preparation tank 10 is set to 8.0, and during the addition of the aqueous solution A, the aqueous solution B is maintained so as to maintain the pH in the seed crystal preparation tank 10 at 8.0 ± 0.1. It was added to precipitate a carbonate compound (seed crystal) containing Ni and Mn.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the seed crystal preparation tank 10 so that the precipitated seed crystals were not oxidized. During the reaction, part of the mixture in the seed crystal preparation tank 10 was circulated through the mixture circulation line 20 and treated with the circulation ultrasonic homogenizer 34. The pump 28 was not operated, and the liquid was not withdrawn from the liquid mixture circulating in the liquid mixture circulation line 20. The overflow method was employed as the precipitation method, and the liquid mixture was drawn from the liquid mixture extraction line 36 so that the liquid volume of the seed crystal preparation tank 10 did not exceed 2 L during the reaction.
A mixed solution which overflowed between 39 and 69 hours from the start of the first addition of the aqueous solution A was recovered, and a seed crystal solution C was obtained. The results and the solid content concentration of the obtained seed crystal solution C are shown in Table 1.

Example 5-1:
The particle growth apparatus 3 shown in FIG. 4 was prepared.
A 2-liter baffled glass reaction vessel 40 was charged with 1.9 liters of distilled water. The transition metal-containing carbonate compound was produced by maintaining the liquid in the reaction tank 40 at 50 ± 1 ° C. with a hot water bath.
While stirring the solution in the reaction vessel 40 with a two-stage inclined paddle type stirring blade 42, the aqueous solution A was continuously added at 5 g / min and the seed crystal solution C at 30 g / h for 92 hours.
The initial pH of the mixture in the reaction vessel 40 is set to 8.0, and during the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added so as to maintain the pH in the reaction vessel 40 at 8.0 ± 0.1. Seed crystals were grown to form transition metal-containing carbonate compounds including Ni and Mn.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the reaction vessel 40 so that the precipitated transition metal-containing carbonate compound was not oxidized. In addition, the overflow method was employed as a precipitation method, and during the reaction, the liquid mixture was drawn from the liquid mixture extraction line 50 so that the liquid volume in the reaction tank did not exceed 2 liters.
The transition metal-containing carbonate compound that overflowed between 21 and 36 hours from the start of the first addition of aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

Example 5-2:
In Example 5-1, the transition metal-containing carbonate compound that overflowed between 63 and 75 hours from the start of the first addition of the aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

Example 5-3:
In Example 5-1, the transition metal-containing carbonate compound which overflowed between 75 to 92 hours from the start of the first addition of the aqueous solution A and the transition metal-containing carbonate compound in the reaction vessel 40 were recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

(Example 6)
Preparation of aqueous solution, seed solution:
An aqueous solution A and an aqueous solution B were prepared in the same manner as in Example 3.
A seed solution C was prepared in the same manner as in Example 4.

Example 6-1:
The particle growth apparatus 3 shown in FIG. 4 was prepared.
A 2-liter baffled glass reaction vessel 40 was charged with 1.9 liters of distilled water. The transition metal-containing carbonate compound was produced by maintaining the liquid in the reaction tank 40 at 50 ± 1 ° C. with a hot water bath.
While stirring the solution in the reaction vessel 40 with a two-stage inclined paddle type stirring blade 42, the aqueous solution A was continuously added at 5 g / minute and the seed crystal solution C at 66 g / hour for 36 hours.
The initial pH of the mixture in the reaction vessel 40 is set to 8.0, and during the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added so as to maintain the pH in the reaction vessel 40 at 8.0 ± 0.1. Seed crystals were grown to form transition metal-containing carbonate compounds including Ni and Mn.
During the precipitation reaction, nitrogen gas was flowed at a flow rate of 0.5 L / min into the reaction vessel 40 so that the precipitated transition metal-containing carbonate compound was not oxidized. In addition, the overflow method was employed as a precipitation method, and during the reaction, the liquid mixture was drawn from the liquid mixture extraction line 50 so that the liquid volume in the reaction tank did not exceed 2 liters.
The transition metal-containing carbonate compound that overflowed between 21 and 36 hours from the start of the first addition of aqueous solution A was recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

Example 6-2:
36 hours after the start of the first addition of the aqueous solution A of Example 6-1, a solution obtained by diluting the aqueous solution A at 5 g / min and doubling the seed crystal solution C was continuously added at 66 g / hour for 30 hours .
During the addition of the aqueous solution A and the seed crystal solution C, the aqueous solution B is added to keep the pH in the reaction vessel 40 at 8.0 ± 0.1, and the seed crystals are grown to contain Ni, Co and Mn. A transition metal-containing carbonate compound was formed.
The transition metal-containing carbonate compound which overflowed between 45 to 66 hours from the start of the first addition of the aqueous solution A and the transition metal-containing carbonate compound in the reaction vessel 40 were recovered. The resulting transition metal-containing carbonate compound was washed and dried as described in Example 1. The results of the above evaluation of the obtained transition metal-containing carbonate compound are shown in Table 2.

The transition metal-containing carbonate compounds of Examples 2-2 to 6 obtained by the production method of the present invention had a high degree of circularity and a narrow particle size distribution.
Although the transition metal-containing carbonate compound of Example 1 obtained by the conventional concentration method had a narrow particle size distribution, it had a low degree of circularity.
The transition metal-containing carbonate compound of Example 2-1 obtained by the conventional overflow method had a wide particle size distribution and a low degree of circularity.

  ADVANTAGE OF THE INVENTION According to the transition metal containing carbonate compound of this invention, the positive electrode active material which can make discharge capacity and cycling characteristics of a lithium ion secondary battery favorable can be obtained.

  1 seed crystal liquid preparation apparatus, 1a seed crystal liquid preparation apparatus, 1b seed liquid crystal preparation apparatus, 1 c seed liquid crystal preparation apparatus, 2 crystal liquid storage tank, 3 particle growth apparatus, 4 first seed crystal liquid transfer line, 5 second seed crystal liquid transfer line, 10 seed crystal liquid preparation tank, 12 stirring blades, 14 aqueous solution A supply line, 16 aqueous solution B supply line, 20 mixed liquid circulation line, 22 pump, 24 MF membrane module, 26 filtrate Discharge line, 28 pumps, 30 hot water baths, 32 shaft generators, 34 circulating ultrasonic homogenizers, 36 mixed liquid extraction lines, 40 reaction vessels, 42 stirring blades, 44 aqueous solution A supply lines, 46 aqueous solution B supply lines, 48 types Crystalline liquid C supply line, 50 mixed liquid extraction line, 52 pump, A aqueous solution, B aqueous solution, C seed liquid

Claims (8)

(A) supplying the following aqueous solution A, the following aqueous solution B and the following seed crystal solution C continuously or intermittently to the reaction vessel,
(B) Stirring a mixed solution containing the following aqueous solution A, the following aqueous solution B and the following seed crystal solution C supplied to the reaction vessel while carrying out the step (a), either one or both of Ni and Co Growing a transition metal-containing carbonate compound containing Mn and Mn;
(C) While carrying out the step (b), a part of the mixed solution containing the transition metal-containing carbonate compound in the reaction vessel is continuously or intermittently withdrawn from the reaction vessel without passing through a filter medium. It possesses a step,
The seed crystal solution C stirs the mixed solution while continuously or intermittently supplying the aqueous solution A and the aqueous solution B to the seed crystal solution preparation tank continuously or intermittently to precipitate seed crystals composed of the carbonate compound. A method for producing a transition metal-containing carbonate compound, which is obtained by :
Aqueous solution A: an aqueous solution containing either or both of Ni ions and Co ions and Mn ions.
Aqueous solution B: aqueous solution containing carbonate ion.
Seed solution C: A solution containing seed crystals consisting of a carbonate compound containing either or both of Ni and Co and Mn, and having a D ₅₀ of less than 5 μm.   In the step (a), the aqueous solution A and the seed crystal solution C are simultaneously supplied to the reaction vessel, and the pH of the mixture in the reaction vessel is in the range of 7 to 9 and the aqueous solution B is The method for producing a transition metal-containing carbonate compound according to claim 1, wherein the compound is continuously or intermittently supplied so that the fluctuation range is ± 0.2. The method for producing a transition metal-containing carbonate compound according to claim 1, wherein the transition metal-containing carbonate compound is grown until the D ₅₀ reaches ₅ to 15 μm in the step (b).   In the step (b), the mixed solution containing the aqueous solution A, the aqueous solution B and the seed crystal solution C supplied to the reaction vessel is maintained in the range of 30 to 50 ° C. and the fluctuation range is ± 2 ° C. The manufacturing method of the transition metal containing carbonate compound as described in any one of Claims 1-3 stirring while stirring. Ni _x Co _y Mn _z M _(1-x-y-z) CO ₃ (where x is 0.15 to 0.5, y is 0 to 0.33, z is 0. 33 to 0.85, x + y + z is 1 or less, M is Mg, Ca, Ba, Sr, Al, Cr, Fe, Ti, Zr, Y, Nb, Mo, Ta, W, Ce and La And one or more selected from the group consisting of
The value at the 50% cumulative frequency of circularity is 0.970 or more,
A transition metal-containing carbonate compound, wherein D ₉₀ / D ₁₀ is 2.5 to 3.5 . D ₅₀ is a 5 to 15 [mu] m, a transition metal-containing carbonate compound according to claim 5. A method of producing a positive electrode active material containing a lithium-containing composite oxide, comprising:
(D) A transition metal-containing carbonate compound obtained by the method for producing a transition metal-containing carbonate compound according to any one of claims 1 to 4 , or a transition metal-containing carbonate according to claim 5 or 6. A method for producing a positive electrode active material, comprising the steps of: mixing a compound and a lithium compound; and calcining the obtained mixture to obtain a lithium-containing composite oxide. In the lithium-containing composite oxide, Li _α Ni _x Co _y Mn _z M _(1-x-y-z) O _β (where α is 1.1 to 1.7 and x is 0.15 ~ 0.5, y is 0-0.33, z is 0.33-0.85, x + y + z is less than 1 and β is Li, Ni, Co, Mn and The manufacturing method of the positive electrode active material according to claim 7 , which is represented by the number of moles of oxygen element (O) necessary to satisfy the valence of M.

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