JP7064717B2 - Manufacturing method of positive electrode active material for non-aqueous electrolyte secondary battery - Google Patents

Description

The present invention relates to a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery.

With the widespread use of mobile devices such as mobile phones and laptop computers, the development of compact and lightweight secondary batteries with high energy density is strongly desired.
Also, in the environment-friendly automobiles called xEVs, the shift from hybrid electric vehicles (HEVs) to plug-in hybrid electric vehicles (PHEVs) and electric vehicles (BEVs) that require high-capacity secondary batteries is progressing. This BEV has a shorter mileage per charge than a gasoline-powered vehicle, and in order to improve this, it is required to increase the capacity of the secondary battery.

As a secondary battery satisfying such a requirement, there is a positive electrode active material for a non-aqueous electrolyte secondary battery, and a typical secondary battery is a lithium ion secondary battery.
This lithium ion secondary battery is composed of a negative electrode, a positive electrode, an electrolytic solution, and the like, and the active material of the negative electrode and the positive electrode is a material capable of desorbing and inserting lithium.
Lithium-ion secondary batteries are currently being actively researched and developed. Among them, lithium-ion secondary batteries using a layered or spinel-type lithium metal composite oxide as a positive electrode material are 4V class. Since a high voltage can be obtained, it is being put into practical use as a battery having a high energy density.

The materials that have been mainly proposed so far are lithium-cobalt composite oxide (LiCoO ₂ ), which is relatively easy to synthesize, lithium-nickel composite oxide (LiNiO ₂ ), and lithium-nickel-cobalt-manganese composite oxidation. Examples thereof include a substance (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) and a lithium-manganese composite oxide using manganese (LiMn ₂ O ₄ ).

In recent years, with the rapid spread of electric vehicles, the demand for lithium-ion secondary batteries with high energy density as a driving power source is increasing, and in particular, Co and thermal stability are required for high energy density. LiNiO ₂ (LiNi _{1-xy Co x} Aly O ₂ , NCA) to which Al has been added for enhancing has been attracting attention.

Further, in the calcining synthesis of LiNiO ₂ , a mixed powder obtained by mixing a lithium compound and a nickel compound such as an oxide or a hydroxide is filled in a funnel or the like and calcined in an oxygen atmosphere, and the LiNiO ₂ is efficient. As a production method, a technique for granulating a mixed powder of a lithium compound and a nickel compound using water as a binder (Patent Document 1) has been reported.
However, since water is used as the binder, there is a problem that the oxygen partial pressure at the time of firing is lowered and the reaction between the lithium compound and the nickel compound is hindered. Further, although a nozzle or the like is normally used when adding water to the binder, there is a concern that contamination may occur due to deterioration of the nozzle or the like.

Japanese Unexamined Patent Publication No. 2000-72446

In order to efficiently mass-produce LiNiO ₂ such as NCA (hereinafter, may be collectively referred to as "lithium-nickel composite oxide"), a method of filling a large amount of mixed powder in a funnel and baking it. However, since oxygen is involved in the synthesis of the lithium-nickel composite oxide, increasing the layer thickness of the mixed powder in the pot reduces the chance that oxygen comes into contact with the mixed powder inside the pot and reacts. In some cases, the firing was completed before the product was completely completed, which deteriorated the product quality.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to be able to produce a compound having a desired crystal structure by firing with high productivity, and to produce lithium having a high purity near a chemical substance composition. -It is an object of the present invention to provide a method for producing a lithium-nickel composite oxide suitable for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, which can easily produce a substance having a nickel composite oxide-based layered rock salt structure.

The first invention of the present invention is a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery containing a lithium-nickel composite oxide, which comprises a mixing step of mixing a nickel compound and a lithium compound to obtain a mixture. The granulation step comprises a granulation step of dry-granulating the mixture to obtain a granulated product composed of the mixture, and a firing step of calcining the granulated product to obtain a lithium-nickel composite oxide. , A non-aqueous electrolyte secondary battery characterized in that a sheet-shaped granulated product is formed using a roll, and the sheet-shaped granulated product is roughly crushed or cut to form a plate-shaped granulated product. This is a method for producing a positive electrode active material for use.

In the second invention of the present invention, the granulation step in the first invention causes the mixture to pass between rolls at a roll linear pressure of 4.9 kN / cm to 10 kN / cm, whereby the sheet-like granulation is performed. It is a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, which is characterized by obtaining a product.

A third aspect of the present invention is a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, wherein the lithium compound in the first and second inventions is lithium hydroxide.

A fourth aspect of the present invention is characterized in that the bulk density of the plate-shaped granules in the first to third inventions is 1.1 to 1.5 times the bulk density of the mixture. This is a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery.

A fifth aspect of the present invention is characterized in that, in the firing steps of the first to fourth inventions, the plate-shaped granules are loaded in a funnel having a layer thickness of 1 mm or more and fired. This is a method for manufacturing a positive electrode active material for an aqueous electrolyte secondary battery.

A sixth aspect of the present invention is a non-aqueous electrolyte secondary battery, which comprises a pulverization step of pulverizing the obtained lithium-nickel composite oxide after the firing step of the first to fifth inventions. This is a method for producing a positive electrode active material for use.

According to the seventh aspect of the present invention, the obtained lithium-nickel composite oxide is washed with water after the firing step in any one of the first to fifth inventions or after the pulverization step in the sixth invention. It is a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, which comprises a step and a drying step of drying the washed lithium-nickel composite oxide.

In the eighth invention of the present invention, the lithium-nickel composite oxide in the first to seventh inventions has a general formula: Liz Ni _{1-xy Co x My} O ₂ (where 0 ≦ _x ≦ 0). .35, 0 ≦ y ≦ 0.35, 0.90 ≦ z ≦ 1.20, M is one or more elements selected from Al, Mn, Mo, W, Mg, Si, B, Nb, V, Ti) It is a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, which is characterized by the above.

INDUSTRIAL APPLICABILITY According to the present invention, a positive electrode active material for a non-aqueous electrolyte secondary battery can be easily produced with high productivity. In particular, it is possible to easily produce a lithium-nickel composite oxide having a chemical quantitative composition that is suitable as a positive electrode active material for a non-aqueous electrolyte secondary battery with high purity on an industrial scale. Extremely high industrial value.

It is a graph which shows the profile by the XRD measurement of the calcined composition of Example 1 of this invention. It is a graph which shows the profile by the XRD measurement of the calcined composition of the comparative example 1. FIG. It is sectional drawing of the coin type battery used for battery evaluation.

[Manufacturing method of positive electrode active material for non-aqueous electrolyte secondary battery]
The present invention is a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery containing a lithium-nickel composite oxide, and is a mixing step of mixing at least a nickel compound containing nickel and a lithium compound in a predetermined amount to obtain a mixture. It is characterized by including a granulation step of drying the mixture to obtain a granulated product and a firing step of calcining the granulated product to obtain a lithium-nickel composite oxide. In addition, if necessary, a crushing step of crushing the lithium-nickel composite oxide after firing, a water washing step of washing and filtering the crushed lithium-nickel composite oxide, and a water-washed lithium-nickel composite oxide. It may be provided with a drying step of drying the composite oxide.

The lithium-nickel composite oxide obtained through the above steps has a crystal structure having a layered structure, and is usually in the form of secondary particles in which primary particles are aggregated. The lithium-nickel composite oxide contains at least Li (lithium) and Ni (nickel), and contains Co (cobalt), Al (aluminum), Mn (manganese), Mo (molybdenum), W (tungsten), and Mg (magnesium). ), Si (silicon), B (boron), Nb (niob), V (vanadium), Ti (tungsten) may contain one or more elements.
Further, the lithium-nickel composite oxide has a general formula: Liz Ni _{1-x-y Co x} My O ₂ (however, 0 ≦ x ≦ 0.35, 0 ≦ _y ≦ 0.35, 0.90 ≦. z ≦ 1.20, M is preferably one or more elements selected from Al, Mn, Mo, W, Mg, Si, B, Nb, V, and Ti), and more preferably the general formula: Li _z Ni. _{1-xy Co x} Ally O ₂ (where 0.03 ≦ x ≦ 0.10, 0.03 ≦ y ≦ 0.10, 0.93 <z <1.03). Such a lithium-nickel composite oxide is suitably used as a positive electrode active material for a non-aqueous electrolyte secondary battery.
Hereinafter, each step will be described in detail.

(Mixing process)
The mixing step is a step in which a nickel compound containing at least nickel and, if necessary, cobalt, aluminum and the like and a lithium compound such as lithium hydroxide and lithium carbonate are weighed in a predetermined amount and then mixed to form a mixed powder.
A general mixer can be used for mixing, and for example, a shaker mixer, a Lady Gemixer, a Julia mixer, a V blender, or the like can be used. Further, this mixing may be sufficiently mixed to the extent that the skeletons of the nickel compound and the lithium compound are not destroyed.

The blending ratio of the nickel compound and the lithium compound is such that the ratio (Li / Me ratio) of the Li element in the lithium compound to the metal element (Me) in the nickel compound is in the range of 0.90 to 1.20. It is preferable to mix them. If the mixing is not sufficient, the Li / Me ratio may vary among the individual particles, and problems such as insufficient battery characteristics may occur.

As the lithium compound, lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate or a mixture thereof can be used, but it is preferable to use lithium hydroxide having a strong binding property from the viewpoint of dry granulation described later.

As the nickel compound, an oxide, a hydroxide or the like can be used, but it is preferable to use an oxide from the viewpoint of reactivity with lithium. Hereinafter, nickel composite oxides and nickel composite hydroxides containing at least nickel and, if necessary, cobalt, aluminum and the like will be described in more detail.

The nickel composite oxide is obtained by oxidizing the nickel composite hydroxide described later. By using an oxide, the amount of water vapor generated during the firing process is reduced, the reaction becomes much easier to proceed, and the firing time is significantly shortened.
Oxidation of the nickel composite hydroxide can be performed by oxidative roasting (heat treatment). Oxidative roasting is preferably carried out, for example, at 600 ° C. or higher and 800 ° C. or lower, 0.5 hours or longer and 3.0 hours or lower. If the temperature of oxidative roasting is less than 600 ° C., moisture may remain and oxidation may not proceed sufficiently.

On the other hand, when the temperature of oxidative roasting exceeds 800 ° C., the composite oxides may be bonded to each other to form coarse particles. In addition, since it uses a lot of energy, it is not industrially suitable from the viewpoint of cost. If the oxidative roasting time is less than 0.5 hours, the oxidation of the nickel composite hydroxide does not proceed sufficiently, and if it exceeds 3.0 hours, the energy cost increases, which is not industrially suitable.

The nickel composite hydroxide contains at least nickel and, if necessary, cobalt, aluminum and the like. Further, manganese, molybdenum, tungsten, magnesium, silicon, boron, niobium, vanadium, titanium and the like may be contained. The method for producing this nickel composite hydroxide is not particularly limited, but for example, a crystallization method can be used.
The composition of the nickel composite hydroxide obtained by this crystallization method becomes uniform in the entire particles, and the composition of the finally obtained lithium-nickel composite oxide also becomes uniform. Since the ratio of each metal element contained in the nickel composite hydroxide is inherited to the nickel composite oxide and the lithium-nickel composite oxide, the composition of the nickel composite hydroxide is finally obtained. The composition of the nickel composite oxide can be similar to that of a metal other than lithium.

The nickel composite hydroxide can be produced, for example, by performing a crystallization reaction in which an aqueous solution containing nickel, cobalt, aluminum and the like is stirred and neutralized with an alkaline aqueous solution.
As the metal salt used when preparing an aqueous solution of nickel or the like, sulfate, chloride, nitrate or the like can be used. Further, if necessary, the crystallization reaction may be carried out in the presence of a complexing agent such as an ammonium ion feeder.
The nickel composite hydroxide obtained by the crystallization method is composed of secondary particles in which the primary particles are aggregated, and the lithium-nickel composite oxide obtained from the nickel composite hydroxide particles is also the secondary particles in which the primary particles are aggregated. It is composed of particles.

The crystallization method is not particularly limited, and for example, a continuous crystallization method, a batch method, or the like can be used.
The continuous crystallization method is, for example, a method of continuously recovering the nickel composite hydroxide overflowing from the reaction vessel, and can easily produce a large amount of nickel composite hydroxides having the same composition. Further, since the nickel composite oxide obtained by the continuous crystallization method has a wide particle size distribution, the packing density of the lithium-nickel composite oxide obtained by using the nickel composite oxide can be improved.

Further, the particle size of the nickel composite hydroxide is, for example, 1 μm or more and 50 μm or less.
The batch method can obtain a nickel composite hydroxide having a more uniform particle size and a narrow particle size distribution. The lithium-nickel composite oxide obtained by using the nickel composite hydroxide obtained by the batch method can react more uniformly with the lithium compound at the time of firing. Further, the nickel composite hydroxide obtained by the batch method can reduce the mixing of fine powder, which is one of the causes of deterioration of cycle characteristics and output characteristics when used in a secondary battery.

(Granulation process)
The granulation step is a step of dry-granulating the mixture without using a binder. For example, the mixed powder is passed between two rolls to which pressure is applied and compacted to dry-granulate the mixture. Therefore, it is preferable to obtain a granulated product composed of a mixture.
In this step, granulation is possible without lowering the reaction efficiency at the time of firing, as compared with the case of using a binder such as water or resin. That is, when a binder is used, more gas is generated than in conventional firing, the oxygen partial pressure on the surface of the mixture increases, and the reactivity decreases.
On the other hand, in the present invention, since a roll utilizing the binding property of the lithium compound is used, it can be consolidated even in dry granulation without using any binder, and does not cause contamination or deterioration of reactivity.

In addition, by granulating, the air permeability between the granulated products is maintained even when the bulk density of the mixture is increased, and the synthetic reaction at the time of firing can be improved in the entire funnel. It can be done and reactivity can be ensured.
Further, since the contact area with the filter bowl, which the mixture was in contact with, can be reduced, the frequency of container breakage problems such as cracking can be reduced, and contamination with the product can be reduced.

Further, since the specific gravity and the particle shape of the lithium salt and the nickel salt are different, even if they are mixed, they are separated when vibration or the like is applied, and the chemical quantitative composition may be locally deviated. Since granulation significantly limits the fluidity of the raw material particles, local compositional deviation does not occur during handling and transportation, and product quality can be improved.

At the time of granulation, it is preferable to pass this mixture between rolls having a roll linear pressure of 4.9 kN / cm to 10 kN / cm to obtain granulated products.
By applying a roll linear pressure of 4.9 kN / cm or more between the rolls, the granulated state can be maintained even during firing. However, if the roll linear pressure exceeds 10 kN / cm, the particles of the nickel compound in the mixture may be cracked and the cycle characteristics and output characteristics may be deteriorated when used in a secondary battery.

The obtained granulated product is in the form of a sheet, and the thickness thereof is preferably 1 mm or more. The upper limit is not particularly limited, but it is preferable that the granulated product does not collapse during handling, and it is preferably 100 mm or less. In addition, since the granulated product is in the form of a sheet, it should be roughly crushed or cut into a plate shape to make it easy to handle and to make it easy to fill in the furnace in the firing process described later. preferable.
The width of the flat surface (the surface flattened by the roll) of the plate-shaped granulated product is preferably at least 5 mm or more. By setting the width of the flat surface of the plate-shaped granulated product to at least 1 mm or more, it is possible to increase the filling amount in the filter pot in the firing step. The upper limit of the width of this plane may be appropriately adjusted according to the shape and size of the filter pot to be used.

As described above, in the present invention, in order to first form a sheet-shaped granule using a roll and then coarsely crush or cut it into a plate-like product, a plate-shaped granule is formed using a molding machine. It is possible to produce granulated products with higher productivity than that.

Further, the bulk density of the plate-shaped granulated product is preferably 1.1 to 1.5 times the bulk density of the mixture before granulation. If the bulk density of the granulated product is less than 1.1 times the bulk density of the mixture before granulation, the consolidation may be insufficient and the granulated product may collapse during handling. If the bulk density of the granulated product exceeds 1.5 times the bulk density of the mixture before granulation, the particles of the nickel compound in the mixture may be cracked when compacted with a roll.

(Baking process)
The firing step is a step of firing the granulated product to obtain a lithium-nickel composite oxide.
In the firing step, it is preferable that the plate-shaped granulated product (mixture) is loaded in a filter pot with a layer thickness of 1 mm or more and fired. As a result, the amount of the mixture that can be filled per pot can be increased as compared with the conventional firing, so that the productivity can be improved.

The firing temperature may be a known condition depending on the composition of the desired lithium-nickel composite oxide and the like. For example, in NCA containing nickel, cobalt and aluminum, the firing temperature can be 650 ° C. or higher and 850 ° C. or lower. Further, it is preferable to bake in an oxidizing atmosphere. As a result, the reactivity between the nickel compound and the lithium compound can be improved, the firing time can be shortened, and the productivity can be further improved.

Since the nickel compound is a specific chemical substance and the lithium compound is an alkaline salt, care must be taken when handling it. When used as a powder, dust is generated when filling the pot, and the working environment However, in the present invention, since the above-mentioned mixture is granulated, the handling and working environment after that can be remarkably improved. Further, when the powder is used as a powder due to the atmospheric gas introduced at the time of firing, it may be scattered in the firing furnace and adhere to the wall surface or the like in the furnace, but by making it a granulated product, the scattering at the time of firing can be suppressed.

(Crushing process)
After the firing step, the obtained lithium-nickel composite oxide may have agglomeration or light sintering necking. Therefore, a crushing step of crushing the obtained lithium-nickel composite oxide as an operation to loosen the agglomeration or light sintering necking should be further provided. Is preferable. A known technique can be used in the crushing step.

(Washing process and drying process)
If impurities or the like remain in the lithium-nickel composite oxide after firing or crushed, and these impurities affect the battery characteristics, a water washing step of washing the lithium-nickel composite oxide with water may be further provided. preferable. In the water washing step, a known technique can be used, for example, washing with pure water can be used. Further, after washing with water, a drying step of performing a drying process for removing water is provided. Known techniques can also be used in the drying step.

Hereinafter, examples of the present invention will be described together with comparative examples.

Nickel oxide powder with an average particle size of 11 μm and lithium hydroxide with an average particle size of 300 μm or less obtained by oxidatively roasting a nickel composite hydroxide having a composition molar ratio of Ni: Co: Al = 88: 9: 3. Was placed in a container and mixed (mixing step).
In order to dry-granulate only the mixture, it is put into a dry granulator (roller compactor), compacted with two rolls in the device without using a binder, and then roughly crushed to a thickness of about 10 mm square. A 1 mm plate-shaped granule was obtained.
The roll linear pressure between the two rolls was set to 4.9 kN / cm (granulation step). When the granulated product was placed in a container having a volume of 90000 mL and the bulk density was measured so as not to apply compaction and vibration, the bulk density was 1.2 times the bulk density of the mixture before granulation.

The obtained plate-shaped granules were placed in a ceramic furnace and calcined in a calcining furnace having an oxidizing atmosphere at a temperature of 765 ° C. to obtain a calcined composite. In addition, the amount to be filled in the filter pot was 1.2 times as large as that of Comparative Example 1 (without granulation step) described later in terms of bulk density (baking step).

After the obtained calcined compound was crushed, the XRD (X-ray diffraction) profile of the calcined compound was measured using Cu K _α rays. As shown in FIG. 1, lithium having a layered rock salt structure was measured. It was confirmed that the nickel composite oxide was obtained.
The bar graph at the bottom of FIGS. 1 and 2 is a profile of the identification object "LiNi _0.9 Co _0.1 O ₂ ".

Using this lithium-nickel composite oxide, a 2032 type coin-type battery 1 shown in FIG. 3 was manufactured and the battery characteristics were measured.
The coin-type battery 1 is composed of a case 2 and an electrode 3 housed in the case 2.
The case 2 has a positive electrode can 2a that is hollow and has one end open, and a negative electrode can 2b that is arranged in the opening of the positive electrode can 2a. When the negative electrode can 2b is arranged in the opening of the positive electrode can 2a, , A space for accommodating the electrode 3 is formed between the negative electrode can 2b and the positive electrode can 2a.
The electrode 3 is composed of a positive electrode 3a, a separator 3c, and a negative electrode 3b, and is laminated so as to be arranged in this order. The positive electrode 3a contacts the inner surface of the positive electrode can 2a, and the negative electrode 3b contacts the inner surface of the negative electrode can 2b. It is housed in the case 2.

The case 2 is provided with a gasket 2c, and the gasket 2c fixes the relative movement between the positive electrode can 2a and the negative electrode can 2b so as to maintain a non-contact state. Further, the gasket 2c also has a function of sealing the gap between the positive electrode can 2a and the negative electrode can 2b and airtightly blocking the space between the inside and the outside of the case 2.

The coin-type battery 1 as described above was manufactured as follows.
First, 52.5 mg of the positive electrode active material for a non-aqueous electrolyte secondary battery, 15 mg of acetylene black, and 7.5 mg of polytetrafluoroethylene resin (PTFE) are mixed and press-molded to a diameter of 11 mm and a thickness of 100 μm at a pressure of 100 MPa. , A positive electrode 3a was produced. The prepared positive electrode 3a was dried in a vacuum dryer at 120 ° C. for 12 hours.
Using the positive electrode 3a, the negative electrode 3b, the separator 3c, and the electrolytic solution, the above-mentioned coin-type battery 1 was produced in a glove box having an Ar atmosphere in which the dew point was controlled to −80 ° C.
For the negative electrode 3b, a graphite powder having an average particle size of about 20 μm punched into a disk shape having a diameter of 14 mm and a negative electrode sheet coated with polyvinylidene fluoride on a copper foil were used. Further, a polyethylene porous membrane having a film thickness of 25 μm was used for the separator 3c. As the electrolytic solution, an equal amount mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) using 1M LiClO ₄ as a supporting electrolyte (manufactured by Tomiyama Pure Chemical Industries, Ltd.) was used.

The initial discharge capacity and positive electrode resistance indicating the performance of the manufactured coin-type battery 1 were evaluated as follows.
After the obtained coin-type battery 1 is manufactured and left to stand for about 24 hours to stabilize the open circuit voltage OCV (Open Circuit Voltage), the current density with respect to the positive electrode is set to 0.1 mA / cm ² and the cutoff voltage is 4.3 V. The battery was charged up to, and the capacity at that time was taken as the charging capacity. The capacity when discharged to a cutoff voltage of 3.0 V after a one-hour rest was defined as the initial discharge capacity.
As a result of the measurement, the charge capacity was 229 mAh / g and the discharge capacity was 210 mAh / g.

(Comparative Example 1)
A calcined composite was obtained under the same conditions as in Example 1 except that the granulation step was not carried out.
When the XRD profile was measured in the same manner as in Example 1, it was confirmed that a lithium-nickel composite oxide having a layered rock salt structure was obtained as shown in FIG. Further, when a coin-type battery 1 was produced using this lithium-nickel composite oxide in the same manner as in Example 1 and the battery characteristics were measured, the charge capacity was 229 mAh / g and the discharge capacity was 208 mAh / g.

Comparing Example 1 and Comparative Example 1, in Example 1, a lithium-nickel composite oxide having a target layered rock salt structure was obtained in the same manner as in Comparative Example 1 produced by the conventional production method, and this was used. It was shown that the battery characteristics of the manufactured batteries were also the same. On the other hand, in the firing step, since the granulation step was provided in Example 1, the filling amount in the funnel was 1.2 times, and the productivity of the firing step was 1.2 times as much as the granulated product. It was shown to be.

1 Coin-type battery 2 Case 2a Positive electrode can 2b Negative electrode can 2c Gasket 3 Electrode 3a Positive electrode 3b Negative electrode 3c Separator

Claims (8)

A method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery containing a lithium-nickel composite oxide.
A mixing step of mixing a nickel compound and a lithium compound to obtain a mixture,
A granulation step of dry-granulating the mixture to obtain a granulated product composed of the mixture.
Including a firing step of calcining the granulated product to obtain a lithium-nickel composite oxide.
The non-granulation step is characterized in that a sheet-shaped granulated product is formed by using a roll, and the sheet-shaped granulated product is roughly crushed or cut to form a plate-shaped granulated product. A method for manufacturing a positive electrode active material for an aqueous electrolyte secondary battery. The first aspect of claim 1, wherein the granulation step obtains the sheet-shaped granulated product by passing the mixture through the rolls at a roll linear pressure of 4.9 kN / cm to 10 kN / cm. A method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery. The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein the lithium compound is lithium hydroxide. The non-aqueous electrolyte according to any one of claims 1 to 3, wherein the bulk density of the plate-shaped granulated product is 1.1 to 1.5 times the bulk density of the mixture. A method for manufacturing a positive electrode active material for a secondary battery. 2. The non-aqueous electrolyte 2 according to any one of claims 1 to 4, wherein in the firing step, the plate-shaped granulated product is loaded in a funnel having a layer thickness of 1 mm or more and fired. A method for manufacturing a positive electrode active material for a secondary battery. The positive electrode activity for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 5, further comprising a crushing step of crushing the obtained lithium-nickel composite oxide after the firing step. Method of manufacturing the substance. After the firing step according to any one of claims 1 to 5 or after the crushing step according to claim 6, a water washing step of washing the obtained lithium-nickel composite oxide with water and the water-washed lithium. The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 6, further comprising a drying step of drying the nickel composite oxide. The lithium-nickel composite oxide has a general formula: Liz Ni _{1-x-y Co x} My O ₂ (where 0 ≦ x ≦ 0.35, 0 ≦ _y ≦ 0.35, 0.90 ≦ z). ≤ 1.20, M is one or more elements selected from Al, Mn, Mo, W, Mg, Si, B, Nb, V, Ti), any one of claims 1 to 7. The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to the above item.

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