JP2018070442A - Nickel composite hydroxide and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nickel composite hydroxide that contains uniformly reduced amounts of sulfate radicals and chlorine.SOLUTION: This invention relates to a nickel composite hydroxide represented by NiCoAl(OH)(0.05≤x≤0.35, 0.01≤y≤0.2, x+y<0.4, and -0.2≤α≤0.2), and includes spherical secondary particles formed by aggregation of a plurality of primary particles. The secondary particles have an average particle diameter of 3 μm or more and 20 μm or less. In the secondary particles, [(d90-d10)/(average particle diameter)], the index which shows the spreading of particle size distribution, is more than 0.55 but 1.20 or less, sulfate radical content is 0.4 mass% or less and chlorine content is 0.05 mass% or less.SELECTED DRAWING: None

Description

  The present invention relates to a nickel composite hydroxide and a method for producing a nickel composite hydroxide.

  In recent years, with the widespread use of portable electronic devices such as mobile phones and laptop computers, development of small and lightweight non-aqueous electrolyte secondary batteries having high energy density is strongly desired. In addition, development of a high output secondary battery is strongly desired as a battery for electric vehicles including hybrid vehicles. As a secondary battery satisfying such requirements, there is a lithium ion secondary battery. A lithium ion secondary battery includes a negative electrode, a positive electrode, an electrolyte, and the like, and a material capable of detaching and inserting lithium is used as an active material for the negative electrode and the positive electrode.

  Research and development of lithium ion secondary batteries are currently being actively conducted. Among them, lithium ion secondary batteries using a layered or spinel type lithium metal composite oxide as a positive electrode material have a high voltage of 4V. Therefore, practical use is progressing as a battery having a high energy density.

In a battery using a lithium cobalt composite oxide (LiCoO ₂ ) that is relatively easy to synthesize as a positive electrode active material of a lithium ion secondary battery, many developments have been made so far to obtain excellent initial capacity characteristics and cycle characteristics. It has already been achieved, and various results have already been obtained. However, since the lithium cobalt composite oxide uses a rare and expensive cobalt compound as a raw material, it causes a cost increase of the positive electrode active material and further the battery using the positive electrode active material, and the replacement of the positive electrode active material is desired. ing.

Therefore, lithium nickel composite oxide (LiNiO ₂ ), which can be expected to have a higher capacity using nickel cheaper than cobalt, has attracted attention. Lithium-nickel composite oxide not only has a low cost but also has a lower electrochemical potential than lithium-cobalt composite oxide. Therefore, decomposition due to oxidation of the electrolyte is less problematic, and higher capacity can be expected. Since it shows a high battery voltage as well as the system, it has been actively developed.

  However, the lithium-nickel composite oxide is said to have inferior cycle characteristics when compared to a cobalt-based lithium ion secondary battery when a lithium-ion secondary battery is produced using a material obtained by synthesizing a metal component other than lithium purely as a positive electrode active material. There are drawbacks. In addition, there is a disadvantage that battery performance is relatively easily lost when used or stored in a high temperature environment.

In order to solve such disadvantages, for example, Patent Document 1 has a layered structure for the purpose of improving storage characteristics such as self-discharge characteristics and structural stability of lithium ion secondary batteries and cycle characteristics of batteries. and the following formula _{Li x Ni a Co b M c} O 2 (0.8 ≦ x ≦ 1.2,0.01 ≦ a ≦ 0.99,0.01 ≦ b ≦ 0.99,0.01 ≦ c ≦ 0.3, 0.8 ≦ a + b + c ≦ 1.2, and M is a lithium-containing composite oxide represented by (at least one element selected from Al, V, Mn, Fe, Cu, and Zn) A positive electrode active material for a lithium secondary battery is proposed.

In Patent Document 2, LiNi _x M _1-x O ₂ (M is Co, Mn, as a positive electrode active material for the purpose of realizing a battery with high capacity and good cycle characteristics and high rate discharge characteristics. One or more of Cr, Fe, V, and Al, x: 1> x ≧ 0.5) has been proposed.

  The lithium nickel composite oxides as described in Patent Documents 1 and 2 are higher in charge capacity and discharge capacity and improved in cycle characteristics than the lithium cobalt composite oxide, but are charged only for the first charge / discharge. There is a problem that the discharge capacity is smaller than the capacity, and the so-called irreversible capacity defined by the difference between the two is large.

  The lithium-nickel composite oxide is usually manufactured from a step of mixing a nickel composite hydroxide with a lithium compound and baking. And nickel composite hydroxide contains impurities, such as a sulfate radical derived from a raw material, in the manufacturing process of nickel composite hydroxide. These impurities often inhibit the reaction with lithium in the step of mixing and baking the lithium compound, and lower the crystallinity of the lithium nickel composite oxide having a layered structure.

  Lithium nickel composite oxide with low crystallinity has a problem in that when a battery is formed as a positive electrode material, Li diffusion in the solid phase is inhibited and the capacity is reduced. Furthermore, the impurities contained in the nickel composite hydroxide remain in the lithium nickel composite oxide even after mixing with the lithium compound and firing. Since these do not contribute to the charge / discharge reaction, when the battery is constructed, the negative electrode material has to be used for the battery by an amount corresponding to the irreversible capacity of the positive electrode material. As a result, the capacity per unit weight and unit volume of the entire battery is reduced. Moreover, it is calculated | required to suppress the excess lithium accumulate | stored in the negative electrode as an irreversible capacity | capacitance from a viewpoint of improving safety.

  For this reason, a lithium nickel composite oxide having a lower impurity content is required. To this end, a nickel composite hydroxide having a lower impurity content is required.

  As a method for producing a nickel composite hydroxide having a low impurity content, Patent Document 3 discloses a nonaqueous electrolyte secondary battery comprising nickel cobalt manganese composite hydroxide particles represented by the following general formula (1). A method for producing a precursor of a positive electrode active material, wherein nickel cobalt manganese composite hydroxide particles are washed with a carbonate aqueous solution having a carbonate concentration of 0.1 mol / L or more, and a non-aqueous electrolyte secondary A method for producing a precursor of a positive electrode active material for a battery is disclosed.

General formula: Ni _x Co _y Mn _z M _t (OH) ₂ (1)
(In the formula, M represents at least one element selected from Mg, Ca, Ba, Sr, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W, and 0.3 ≦ x ≦ 0.4, 0.3 ≦ y ≦ 0.4, 0.3 ≦ z ≦ 0.4, 0 ≦ t ≦ 0.1, and x + y + z + t = 1.)
However, according to the method for producing a precursor of the positive electrode active material for a non-aqueous electrolyte secondary battery disclosed in Patent Document 3, the nickel-cobalt-manganese composite hydroxide particles subjected to the cleaning are locally contaminated. There is a concern that the content becomes high.

  For this reason, for example, there is a possibility that a nickel composite hydroxide that is reduced evenly with respect to the sulfate content or chlorine content that is particularly problematic as impurities cannot be obtained.

Japanese Patent Laid-Open No. 08-213015 Japanese Patent Laid-Open No. 09-129230 JP2015-162322A

  Therefore, in view of the problems of the above-described conventional techniques, an object of one aspect of the present invention is to provide a nickel composite hydroxide in which the content of sulfate radicals and chlorine is uniformly reduced.

In order to solve the above problems, according to one aspect of the present invention,
In one aspect of the present invention, the general formula _{Ni 1-x-y Co x} Al y (OH) 2 + α (0.05 ≦ x ≦ 0.35,0.01 ≦ y ≦ 0.2, x + y <0.4, −0.2 ≦ α ≦ 0.2),
Containing spherical secondary particles formed by aggregation of a plurality of primary particles,
The secondary particles have an average particle size of 3 μm or more and 20 μm or less, and the secondary particles are an index indicating the spread of the particle size distribution [(d90−d10) / average particle size] larger than 0.55. 20 or less,
Provided is a nickel composite hydroxide having a sulfate radical content of 0.4 mass% or less and a chlorine content of 0.05 mass% or less.

  According to one embodiment of the present invention, it is possible to provide a nickel composite hydroxide in which the content of sulfate radicals and chlorine is uniformly reduced.

  Below, one structural example of the manufacturing method of nickel composite hydroxide and nickel composite hydroxide is demonstrated in detail. Note that the present invention is not limited to the following detailed description unless otherwise specified. The embodiment according to the present invention will be described in the following order.

1. Nickel composite hydroxide 2. Manufacturing method of nickel composite hydroxide 3. Positive electrode active material for non-aqueous electrolyte secondary battery 4. Manufacturing method of positive electrode active material for non-aqueous electrolyte secondary battery Non-aqueous electrolyte secondary battery

1. Nickel Nickel composite hydroxide of the composite hydroxide present embodiment, the general formula _{Ni 1-x-y Co x} Al y (OH) 2 + α (0.05 ≦ x ≦ 0.35,0.01 ≦ y ≦ 0 .2, x + y <0.4, −0.2 ≦ α ≦ 0.2). And it is preferable that content of a sulfate radical is 0.4 mass% or less, and content of chlorine is 0.05 mass% or less.

Further, the nickel composite hydroxide of the present embodiment contains spherical secondary particles formed by aggregation of a plurality of primary particles, and the secondary particles have an average particle size of 3 μm or more and 20 μm or less, The secondary particles preferably have [(d90−d10) / average particle size], which is an index indicating the spread of the particle size distribution, greater than 0.55 and not greater than 1.20.
[Composition of nickel composite hydroxide]
Nickel composite hydroxide of the present embodiment, the general formula _{Ni 1-x-y Co x} Al y (OH) 2 + α (0.05 ≦ x ≦ 0.35,0.01 ≦ y ≦ 0.2, x + y < 0.4, −0.2 ≦ α ≦ 0.2).

  In the above general formula, x indicating the cobalt content is 0.05 ≦ x ≦ 0.35. A non-aqueous electrolyte secondary battery using a positive electrode active material for a non-aqueous electrolyte secondary battery (hereinafter, also simply referred to as “positive electrode active material”) obtained from the nickel composite hydroxide by appropriately containing cobalt The cycle characteristics of the crystal lattice (hereinafter also simply referred to as “battery”) and the expansion / contraction behavior of the crystal lattice due to Li insertion / desorption associated with charge / discharge can be reduced.

  When the cobalt content x is 0.05 or more, the positive electrode active material obtained from the nickel composite hydroxide is preferable because the above-described effects can be sufficiently exhibited. However, if the cobalt content is too high and x exceeds 0.35, the initial discharge capacity of the battery using the positive electrode active material obtained from the nickel composite hydroxide may be greatly reduced, and the cost is further reduced. There are also disadvantages.

  Therefore, x indicating the cobalt content of the nickel composite hydroxide of this embodiment is preferably 0.05 ≦ x ≦ 0.35, and a positive electrode active material obtained from the nickel composite hydroxide is used. In view of the battery characteristics and cost of the conventional battery, 0.07 ≦ x ≦ 0.25 is more preferable, and 0.10 ≦ x ≦ 0.20 is further preferable.

  In the above general formula, y indicating the aluminum content is 0.01 ≦ y ≦ 0.2, and preferably 0.01 ≦ y ≦ 0.1. When the aluminum content is in the above range, the durability and safety of the battery using the positive electrode active material obtained from the nickel composite hydroxide can be improved.

  In particular, it is preferable that aluminum is uniformly distributed inside the nickel composite hydroxide particles. When aluminum is uniformly distributed inside the nickel composite hydroxide particles, a greater effect can be obtained with the same aluminum content as compared with the case where the uniformity of aluminum distribution is low. A battery using a positive electrode active material obtained from an oxide has an advantage that a decrease in battery capacity can be suppressed.

  As described above, it is preferable to set the aluminum content y to 0.01 or more because the above-described effects can be obtained particularly sufficiently. In addition, when the aluminum content y is 0.2 or less, when the positive electrode active material obtained from the nickel composite hydroxide is used as a positive electrode material of a battery, the positive electrode active material is subjected to an oxidation-reduction reaction in the battery. This is because the metal element that contributes is particularly sufficiently contained, so that the battery capacity can be particularly increased, which is preferable. For this reason, as above-mentioned, it is preferable that y which shows aluminum content is 0.01 <= y <= 0.2.

  Furthermore, the total atomic ratio of the cobalt content x and the aluminum content y can be x + y <0.4. This is because when the total atomic ratio of the cobalt content and the aluminum content is 0.4 or more, the capacity of the battery using the positive electrode active material obtained from the nickel composite hydroxide may be reduced.

The method for analyzing the composition of the nickel composite hydroxide of the present embodiment is not particularly limited, but can be determined using chemical analysis by ICP emission spectroscopy.
[Particle structure]
The nickel composite hydroxide of the present embodiment can contain spherical secondary particles formed by aggregating a plurality of primary particles, and can also be composed of such spherical secondary particles. The shape of the primary particles constituting the secondary particles is not particularly limited, and various forms such as a plate shape, a needle shape, a rectangular parallelepiped shape, an elliptical shape, and a rhombohedral shape can be adopted. In particular, the primary particles constituting the secondary particles preferably have one or more shapes selected from a plate shape and a needle shape. In addition, the aggregation state of the plurality of primary particles constituting the secondary particles is not particularly limited, and may be a form of aggregation in a random direction or a form of aggregation in the major axis direction of the primary particles radially from the center. May be.

  As the aggregation state, it is preferable that primary particles of one or more shapes selected from a plate shape and a needle shape are aggregated in a random direction to form secondary particles. This is because, in the case of such a structure, voids are almost uniformly formed between the primary particles, and when the lithium compound is mixed and baked to form the positive electrode active material, the molten lithium compound becomes secondary particles. This is because the lithium is sufficiently diffused.

In addition, although the shape observation method of a primary particle and a secondary particle is not specifically limited, It can observe by observing the cross section of a nickel composite hydroxide using a scanning electron microscope.
[Average particle size]
In the nickel composite hydroxide of the present embodiment, it is preferable that the secondary particles contained therein have an average particle size of 3 μm or more and 20 μm or less. This is because when the average particle size of the secondary particles contained is 3 μm or more, a positive electrode active material is generated from the nickel composite hydroxide, and the packing density of the particles can be sufficiently increased when used as a positive electrode. This is because the battery capacity per unit volume can be increased. On the other hand, by making the average particle size of the secondary particles contained in the nickel composite hydroxide of this embodiment 20 μm or less, the specific surface area of the positive electrode active material generated from the nickel composite hydroxide is sufficiently increased. Can do. For this reason, by using the positive electrode active material for the positive electrode of the battery, a sufficient interface between the positive electrode active material and the battery electrolyte can be secured, reaction resistance can be suppressed, and the output characteristics of the battery can be improved. It is possible and preferable. Therefore, the nickel composite hydroxide preferably contains secondary particles having an average particle size of 3 μm or more and 20 μm or more.

  In particular, when the average particle size of the secondary particles contained in the nickel composite hydroxide of the present embodiment is 7 μm or more and 15 μm or less, in a battery using a positive electrode active material obtained from the nickel composite hydroxide for the positive electrode, the unit volume The battery capacity per unit can be particularly increased, and the output characteristics of the battery can be particularly improved, which is more preferable.

The method for measuring the average particle diameter is not particularly limited, and can be determined from, for example, the volume integrated value measured with a laser light diffraction / scattering particle size analyzer.
[Impurity content]
Nickel composite hydroxides usually originate from manufacturing processes and contain sulfate radicals and chlorine as impurities. Sulfate radicals and chlorine are derived from, for example, the raw materials used in the crystallization process described later.

  On the other hand, the nickel composite hydroxide of this embodiment has a sulfate radical content of 0.4% by mass or less, and preferably 0.3% by mass or less. Furthermore, the nickel composite hydroxide of the present embodiment has a chlorine content of 0.05% by mass or less, and preferably 0.03% by mass or less.

  This is because, by setting the sulfate radical content in the nickel composite hydroxide to 0.4 mass% or less, a positive electrode active material is produced. Therefore, the nickel composite hydroxide and the lithium compound are mixed and fired. This is because the reaction between lithium and the nickel composite hydroxide can proceed without being hindered. Moreover, it is because the crystallinity of the lithium nickel composite oxide having a layered structure, which is a positive electrode active material obtained by the reaction between the nickel composite hydroxide and the lithium compound, can be made sufficiently high.

  Moreover, in order to produce a positive electrode active material by setting the chlorine content in the nickel composite hydroxide to 0.05 mass% or less, the nickel composite hydroxide and the lithium compound are mixed and fired. In addition, the reaction between lithium and nickel composite hydroxide can proceed without being inhibited. Moreover, it is because the crystallinity of the lithium nickel composite oxide having a layered structure, which is a positive electrode active material obtained by the reaction between the nickel composite hydroxide and the lithium compound, can be made sufficiently high.

  When a battery having a high crystallinity using lithium nickel composite oxide as a positive electrode active material is constructed, Li diffusion is sufficiently promoted in the solid phase, and the battery capacity can be increased.

  Impurities contained in the nickel composite hydroxide also remain in the lithium nickel composite oxide obtained by mixing and firing the nickel composite hydroxide and the lithium compound. Since these impurities do not contribute to the charge / discharge reaction, when the battery is configured, the negative electrode material has to be used in the battery by an amount corresponding to the irreversible capacity of the positive electrode material. As a result, the capacity per unit weight and unit volume of the entire battery is reduced. Further, it is preferable to suppress excess lithium accumulated in the negative electrode as an irreversible capacity from the viewpoint of enhancing safety. For this reason, from the viewpoint of increasing the battery capacity per unit weight or unit volume, and also from the viewpoint of improving safety, the sulfate radical content of the nickel composite hydroxide of the present embodiment is 0.4% by mass or less. The chlorine content is preferably 0.05% by mass or less.

  Furthermore, the chlorine in the nickel composite hydroxide is mainly contained in the form of LiCl or NaCl in the lithium nickel composite oxide when the lithium nickel composite oxide as the positive electrode active material is produced from the nickel composite hydroxide. Remains. Since LiCl and NaCl are highly hygroscopic, when the positive electrode active material is used in a battery, it causes moisture to be brought into the battery and further causes deterioration of the battery. For this reason, it is preferable that the chlorine content in the nickel composite hydroxide of the present embodiment is 0.05% by mass or less.

  In addition, the nickel composite hydroxide of the present embodiment can be a nickel composite hydroxide in which the sulfate radicals and the chlorine content are uniformly reduced. For this reason, when the nickel composite hydroxide of the present embodiment is sampled at a plurality of locations, it is preferable that the sulfate radical content and the chlorine content satisfy the above-described ranges at all locations. When the sample is sampled and evaluated, the variation of the sulfate radical content and the chlorine content is preferably ± 20% or less.

In addition, when the nickel composite hydroxide is sampled at a plurality of locations and the content of sulfate radicals and chlorine is evaluated, the number of sampling locations is not particularly limited. For example, sampling is performed at 2 to 10 locations. It is preferable to carry out.
[Particle size distribution]
The secondary particles contained in the nickel composite hydroxide of the present embodiment have an index ((d90-d10) / average particle size) that indicates the spread of the particle size distribution of the particles and is greater than 0.55 and less than or equal to 1.20. Preferably there is.

  When the positive electrode active material obtained from the nickel composite hydroxide of the present embodiment is used as a positive electrode material of a battery, the particle size distribution of the positive electrode active material preferably has a certain spread. This is because when the particle size distribution of the positive electrode active material has a certain spread, the electrode plate of the battery produced using the positive electrode active material can sufficiently secure the particle density per electrode plate, and the unit weight of the battery This is because the battery capacity per unit or unit volume can be increased.

  Here, according to the study of the inventors of the present invention, the positive electrode active material and the secondary particles contained in the nickel composite hydroxide as the raw material of the positive electrode active material have the same particle size distribution spread. doing. When [(d90−d10) / average particle size], which is an index indicating the spread of the particle size distribution of the secondary particles contained in the nickel composite hydroxide, is greater than 0.55, it is generated from the nickel composite hydroxide. In the electrode plate of the battery using the positive electrode active material, the particle density per electrode plate can be sufficiently increased, which is preferable.

  However, when [(d90-d10) / average particle size] is greater than 1.20, fine particles having a very small particle size with respect to the average particle size, or particles having a very large particle size with respect to the average particle size (Large-diameter particles) are present in an excessive amount. When the positive electrode active material produced from such nickel composite hydroxide is used, the battery capacity per unit weight or per unit volume can be increased.

  However, when a positive electrode is formed using a positive electrode active material in which a large amount of fine particles are present, heat may be generated due to local reaction of the fine particles, and the fine particles are selectively deteriorated, resulting in poor cycle characteristics. It is not preferable because there is a risk of doing so. On the other hand, when a positive electrode is formed using a positive electrode active material having a large number of large particles, the reaction area between the electrolyte and the positive electrode active material may not be sufficient, and the battery output may decrease due to an increase in reaction resistance. This is not preferable.

  Therefore, the secondary particles contained in the nickel composite hydroxide of the present embodiment have an index ((d90-d10) / average particle size) that indicates an expansion of the particle size distribution of the particles, greater than 0.55 and 1.20. The following is preferable. When the secondary particles contained in the nickel composite hydroxide of the present embodiment have such a particle size distribution, for a battery using a positive electrode active material obtained from the nickel composite hydroxide, per unit weight or per unit volume This is preferable because the battery capacity can be increased and the cycle characteristics and battery output can be increased.

  In addition, in the index [(d90−d10) / average particle size] indicating the spread of the particle size distribution, d10 is the cumulative volume of all particles when the number of particles in each particle size is accumulated from the smaller particle size. It means the particle size which becomes 10% of the total volume. Further, d90 means a particle size in which the cumulative volume becomes 90% of the total volume of all particles when the number of particles in each particle size is accumulated from the smallest particle size.

  The method for obtaining the average particle diameter and d90 and d10 is not particularly limited, and for example, it can be obtained from the volume integrated value measured with a laser light diffraction / scattering particle size analyzer. In addition, it can obtain | require similarly about the average particle diameter in other part of this specification, d90, and d10.

  According to the nickel composite hydroxide of the present embodiment, the sulfate radicals and the chlorine content can be uniformly reduced. For this reason, when a non-aqueous electrolyte secondary battery is produced using a positive electrode active material obtained from the nickel composite hydroxide, the battery can be a battery having a large battery capacity and excellent safety. For this reason, the nickel composite hydroxide of this embodiment is a battery material for an electric vehicle that is driven only by electric energy, or a non-aqueous electrolyte for a plug-in hybrid vehicle that can be charged directly from an outlet using an insertion plug. It can be suitably used as a precursor of a positive electrode active material of a secondary battery.

2. Manufacturing method of nickel composite hydroxide One structural example of the manufacturing method of the nickel composite hydroxide of this embodiment is demonstrated. In addition, since the nickel composite hydroxide described above can be manufactured by the method for manufacturing the nickel composite hydroxide of the present embodiment, a part of the overlapping description is omitted.

  The manufacturing method of the nickel composite hydroxide of this embodiment can have the following processes.

A supply step of supplying the nickel composite hydroxide slurry into the squeezing means via a supply pipe.
A filtration step of filtering the nickel composite hydroxide slurry by a squeezing means to obtain a nickel composite hydroxide cake.
A washing step of washing the nickel composite hydroxide cake in the pressing means.

  And the said washing | cleaning process can have the following steps further.

In a state where the nickel composite hydroxide cake is squeezed by the squeezing means, an alkaline liquid is supplied to the nickel composite hydroxide cake via the cleaning liquid pipe connected to the squeezing means, and the nickel composite hydroxide cake is washed. First washing step.
The 2nd washing | cleaning step which supplies an alkaline liquid in a pressing means via supply piping in the state which is not squeezing nickel composite hydroxide cake, and re-squeezes nickel composite hydroxide cake after that.

Hereinafter, each step will be described.
[Supply process, Filtration process]
Since the nickel composite hydroxide obtained by various methods contains impurities, the impurities can be removed by performing a filtration step and a cleaning step described later.

  As a method of cleaning the nickel composite hydroxide, for example, a method of adding nickel composite hydroxide to an alkaline liquid, slurrying and cleaning, and then filtering can be considered. Moreover, after supplying the slurry containing the nickel composite hydroxide produced | generated from the coprecipitation process to a filter and making it into a cake, the method of conveying a cake to another washing | cleaning means and washing | cleaning etc. can also be considered.

  However, it is preferable to carry out filtration and washing using a squeezing means that can continuously carry out filtration and washing with the same equipment. For this reason, it is preferable to set it as the process of supplying a nickel composite hydroxide slurry in a pressing means via the supply piping connected to this pressing means in a pressing means.

  And in a filtration process, the nickel composite hydroxide slurry supplied in the pressing means can be filtered by the pressing means to obtain a nickel composite hydroxide cake.

In addition, as a pressing means, what is necessary is just a means which can implement filtration and washing | cleaning about nickel composite hydroxide slurry as mentioned above, and is not specifically limited. As the squeezing means capable of performing filtration and washing, for example, one or more types selected from a filter press, a belt filter and the like can be preferably used.
[Washing process]
The cleaning process can have two cleaning steps, the following first cleaning step and second cleaning step. Each step will be specifically described below.
(First cleaning step)
In a 1st washing | cleaning step, in the state which pressed the nickel composite hydroxide cake by the pressing means after the filtration process as stated above, it is made into a nickel composite hydroxide cake as washing | cleaning liquid via the washing liquid piping connected to the pressing means. An alkaline liquid can be supplied to wash the nickel composite hydroxide cake.

  When an alkaline liquid, which is a cleaning liquid, is passed through the filtered nickel composite hydroxide cake under pressure, the cleaning liquid is uniformly passed through the cake, improving the cleaning efficiency and reducing the amount of cleaning liquid. The amount of impurities in the nickel composite hydroxide can be uniformly reduced to the target concentration.

  As the cleaning liquid used in the first cleaning step, an alkaline liquid can be preferably used. The alkaline liquid used as the cleaning liquid is not particularly limited, but is preferably at least one aqueous solution selected from sodium carbonate, potassium carbonate, sesquisodium carbonate, sodium bicarbonate, potassium bicarbonate, and sodium hydroxide.

  Also, the concentration of the alkaline liquid is not particularly limited. For example, the lower limit is preferably 0.10 mol / L or more, more preferably 0.15 mol / L or more, and More preferably, it is 20 mol / L or more. Moreover, it is preferable that an upper limit is 2.00 mol / L or less, and it is more preferable that it is 1.50 mol / L or less.

  By using an alkaline liquid having a concentration of 0.10 mol / L or more as the cleaning liquid, impurities in the nickel composite hydroxide particles, particularly sulfate radicals and chlorine, can be removed by the ion exchange action of ions contained in the cleaning liquid. This is because it can be efficiently removed. However, even if the concentration exceeds 2.00 mol / L, a large difference does not occur in the effect of removing impurities in the nickel composite hydroxide particles, and therefore it is preferably 2.00 mol / L or less.

  The liquid temperature (water temperature) of the alkaline liquid used as the cleaning liquid is not particularly limited, but is preferably 15 ° C. or higher and 50 ° C. or lower, for example. This is because when the temperature of the cleaning liquid is within the above range, the ion exchange reaction becomes active and the impurity removal proceeds efficiently.

  The supply amount of the alkaline liquid used as the cleaning liquid in the first cleaning step is not particularly limited. For example, it is preferably 1000 mL or more, more preferably 2000 mL or more with respect to 1000 g of the nickel composite hydroxide. preferable. The upper limit value of the supply amount of the alkaline liquid used as the cleaning liquid in the first cleaning step is not particularly limited, but is preferably 5000 mL or less with respect to 1000 g of nickel composite hydroxide, for example.

  This is because, in the first cleaning step, the supply amount of the alkaline liquid used as the cleaning liquid is set to 1000 mL or more with respect to 1000 g of the nickel composite hydroxide, thereby sufficiently removing impurity ions contained in the nickel composite hydroxide. Because it can be done. Moreover, even if it supplies more alkaline liquid than 5000 mL with respect to 1000 g of nickel composite hydroxide, there is not much difference in an effect about impurity removal.

  In the first cleaning step, the alkaline liquid used as the cleaning liquid is supplied and the cleaning time is not particularly limited, but may be, for example, 0.2 hours or more and 1 hour or less.

  In the first cleaning step, after cleaning using an alkaline liquid as a cleaning liquid, it is preferable to perform cleaning with pure water by switching the cleaning liquid to pure water as necessary. This is to remove cationic impurities such as sodium derived from the alkaline liquid used as the cleaning liquid. The method of cleaning with pure water is not particularly limited. For example, it is preferable to perform continuous water cleaning with pure water by switching the cleaning liquid to pure water after water cleaning using an alkaline liquid as a cleaning liquid. That is, in a state where the nickel composite hydroxide cake is squeezed by the squeezing means, pure water is supplied to the nickel composite hydroxide cake via the cleaning liquid pipe connected to the squeezing means, and the nickel composite hydroxide cake is washed. be able to.

  In the first washing step, the squeezing pressure when squeezing the nickel composite hydroxide cake may be lower than the re-pressing pressure in re-squeezing the nickel composite hydroxide cake in the second washing step of the next step. preferable. This is because if the pressing pressure in the first cleaning step is higher than the re-pressing pressure in the second cleaning step, a portion where the cake becomes locally consolidated is formed, and the cleaning liquid may not flow easily.

  In the first washing step, the pressing pressure when pressing the nickel composite hydroxide cake is not particularly limited, but is preferably 0.2 MPa or more and 0.5 MPa or less, for example.

  By setting the pressing pressure in the first cleaning step to 0.2 MPa or more, the nickel composite hydroxide cake can be fully squeezed as a whole, and the ion-exchanged cleaning solution containing impurities can be converted into nickel composite. This is because it can be sufficiently removed from the hydroxide cake and the amount of impurities can be sufficiently reduced. On the other hand, if the pressing pressure in the first cleaning step is too high, there is a risk that the nickel composite hydroxide cake will be excessively pressed and the cleaning liquid will not flow easily, but if the pressing pressure is 0.5 MPa or less, The cleaning liquid is preferable because it can be surely distributed over the entire nickel composite hydroxide cake and can be uniformly cleaned.

In addition, also when wash | cleaning a nickel composite hydroxide cake with pure water after washing | cleaning by a washing | cleaning liquid as mentioned above, it is preferable that the nickel composite hydroxide cake is squeezed. And although it does not specifically limit about the pressing pressure at the time of wash | cleaning a nickel composite hydroxide cake with a pure water, It is preferable that it is 0.2 MPa or more and 0.5 MPa or less for the same reason as the above-mentioned case.
(Second cleaning step)
The squeezing means is usually connected to a cleaning liquid pipe for supplying a cleaning liquid, a supply pipe for supplying an object to be squeezed to the squeezing means, and a drain pipe for discharging the squeezed liquid to the outside. Yes.

  And when wash | cleaning by a pressing means, it is common to wash | clean by supplying a cleaning liquid only from cleaning liquid piping. That is, as in the first cleaning step, the cleaning liquid is generally supplied only from the cleaning liquid piping and cleaning is performed.

  However, according to the study of the inventors of the present invention, in addition to the first cleaning step, the second cleaning step is performed, and in this second cleaning step, the cleaning liquid is supplied from the supply pipe which is a pipe different from the cleaning liquid pipe. It has been found that the impurities in the nickel composite hydroxide cake can be significantly and uniformly reduced by supplying.

  According to the study by the inventors of the present invention, the nickel composite hydroxide cake in the supply pipe or in the vicinity of the outlet of the supply pipe is not easily cleaned if the cleaning liquid is supplied from the cleaning liquid pipe. For this reason, there is a possibility that nickel composite hydroxide cake that has not been sufficiently cleaned may be mixed in only by performing the first cleaning step described above. Therefore, the second cleaning step is performed, and in the second cleaning step, the cleaning liquid is supplied from the supply pipe, so that the supply pipe and the nickel composite hydroxide cake near the outlet can be sufficiently cleaned. The impurity concentration in the nickel composite hydroxide cake can be greatly and uniformly reduced.

  As the cleaning liquid used in the second cleaning step, an alkaline liquid can be preferably used. Although it does not specifically limit as an alkaline liquid used as a washing | cleaning liquid, What was demonstrated as an alkaline liquid which can be used suitably at a 1st washing | cleaning step can be used preferably.

  Also, the concentration of the alkaline liquid is not particularly limited. For example, the lower limit is preferably 0.10 mol / L or more, more preferably 0.15 mol / L or more, and More preferably, it is 20 mol / L or more. Moreover, it is preferable that an upper limit is 2.00 mol / L or less, and it is more preferable that it is 1.50 mol / L or less.

  By using an alkaline liquid having a concentration of 0.10 mol / L or more as the cleaning liquid, impurities in the nickel composite hydroxide particles, particularly sulfate radicals and chlorine, can be removed by the ion exchange action of ions contained in the cleaning liquid. This is because it can be removed efficiently. However, even if the concentration exceeds 2.00 mol / L, a large difference does not occur in the effect of removing impurities in the nickel composite hydroxide particles, and therefore it is preferably 2.00 mol / L or less.

  The liquid temperature (water temperature) of the alkaline liquid used as the cleaning liquid is not particularly limited, but is preferably 15 ° C. or higher and 50 ° C. or lower, for example. This is because when the temperature of the cleaning liquid is within the above range, the ion exchange reaction becomes active and the impurity removal proceeds efficiently.

  The supply amount of the alkaline liquid used as the cleaning liquid in the second cleaning step is not particularly limited. For example, it is preferably 150 mL or more, more preferably 250 mL or more with respect to 1000 g of nickel composite hydroxide. preferable. The upper limit of the supply amount of the alkaline liquid used as the cleaning liquid in the second cleaning step is not particularly limited, but is preferably 5000 mL or less with respect to 1000 g of the nickel composite hydroxide, for example.

  This is because, in the second cleaning step, the supply amount of the alkaline liquid used as the cleaning liquid is 150 mL or more with respect to 1000 g of the nickel composite hydroxide, thereby sufficiently removing impurity ions contained in the nickel composite hydroxide. Because it can be done. Moreover, even if it supplies more alkaline liquid than 5000 mL with respect to 1000 g of nickel composite hydroxide, there is not much difference in an effect about impurity removal.

  Note that the alkaline liquid used as the cleaning liquid in the first cleaning step and the alkaline liquid used as the cleaning liquid in the second cleaning step may be the same or different. However, in order to avoid that different kinds of cations derived from the cleaning liquid remain in the nickel composite hydroxide cake, it is preferable to use the same alkaline liquid as the cleaning liquid in the first cleaning step and the second cleaning step. .

  In the second cleaning step, an alkaline liquid as a cleaning liquid is supplied and the cleaning time is not particularly limited, but may be, for example, 0.05 hours or more and 1 hour or less.

  Also in the second cleaning step, as described in the first cleaning step, after cleaning using an alkaline liquid as the cleaning liquid, it is preferable to perform cleaning with pure water by switching the cleaning liquid to pure water as necessary. This is to remove cationic impurities such as sodium derived from the alkaline liquid used as the cleaning liquid. The method of cleaning with pure water is not particularly limited. For example, it is preferable to perform continuous water cleaning with pure water by switching the cleaning liquid to pure water after water cleaning using an alkaline liquid as a cleaning liquid. That is, pure water is supplied to the nickel composite hydroxide cake through a supply pipe connected to the squeezing means in a state where the nickel composite hydroxide cake is not compressed, and the nickel composite hydroxide cake is washed. Can do.

  In the second cleaning step, it is preferable to re-squeeze the nickel composite hydroxide cake after passing an alkaline liquid or pure water. By re-pressing, cation impurities remaining in the nickel composite hydroxide cake can be removed together with moisture, and the amount of impurities in the nickel composite hydroxide cake can be further reduced. Moreover, it is because the usage-amount of the hot air used can be reduced by implementing the drying process etc., for example after a 2nd washing | cleaning step by lowering | hanging the moisture content of a nickel composite hydroxide cake.

  In the second washing step, the re-pressing pressure when re-pressing the nickel composite hydroxide cake is not particularly limited, but is preferably, for example, 0.25 MPa or more and 0.8 MPa or less. This is because the nickel composite hydroxide cake can be sufficiently re-pressed by setting the re-pressing pressure to 0.25 MPa or more. From the nickel composite hydroxide cake, the washing liquid containing impurities and the washing water are sufficient. This is because it can be removed. Moreover, as will be described later, for example, the cake can be easily dried when a drying process or the like is performed after the second cleaning step, and in that case, the cleaning liquid and the cleaning water containing impurities can be sufficiently removed. This is because the impurity concentration can be particularly reduced.

  However, if the pressure exceeds 0.8 MPa, the pressure applied to the compressed rubber or the filter cloth increases, and the filter cloth may be broken, and therefore, the recompression pressure is preferably 0.8 MPa or less.

  In addition, when the obtained nickel composite hydroxide cake is subjected to a drying step or the like after completion of the cleaning step, the nickel composite hydroxide cake can be easily recovered from the squeezing means for efficient drying. The composite hydroxide cake is preferably dehydrated so that the water content is 10% or more and 30% or less.

  The manufacturing method of the nickel composite hydroxide of this embodiment can also have arbitrary processes in addition to the above-mentioned supply process, filtration process, and washing | cleaning process.

  For example, it may have a coprecipitation process for producing a nickel composite hydroxide.

A configuration example of the coprecipitation step will be described below.
[Co-precipitation process]
In the coprecipitation step, the nickel composite hydroxide slurry to be supplied to the pressing means can be generated in the supply step described above.

  A coprecipitation process can have the following steps, for example.

  An initial aqueous solution preparation step of preparing an initial aqueous solution containing an Ni / Co-containing mixed aqueous solution containing nickel and cobalt, an ammonium ion supplier, and an aluminum source in a reaction vessel.

And the alkaline solution supply step which supplies an alkaline solution, Ni / Co containing mixed aqueous solution, an ammonium ion supply body, an aluminum source etc. to an initial stage aqueous solution continuously, and forms mixed aqueous solution.
In the alkaline solution supply step, it is preferable to control the pH value of the mixed aqueous solution, which is measured with the liquid temperature of 25 ° C. as a reference, to be 11.0 or higher and 12.8 or lower.

  In the alkaline solution supply step, the nickel composite hydroxide can be co-precipitated in the reaction tank so as to have the atomic ratio of the general formula of the nickel composite hydroxide described above, and the nickel composite can be overflowed from the reaction tank. The hydroxide can be recovered.

  In the coprecipitation step, since the nucleation reaction and the particle growth reaction proceed simultaneously in the same reaction tank, the particle size distribution of the obtained nickel composite hydroxide can be widened.

Hereinafter, each step will be described.
(Initial aqueous solution preparation step)
In the initial aqueous solution preparation step of the coprecipitation step, an initial aqueous solution containing a Ni / Co-containing mixed aqueous solution containing nickel and cobalt, an ammonium ion supplier, and an aluminum source can be prepared in the reaction vessel. Hereinafter, each component contained in the initial aqueous solution will be described.
(1) Ni / Co-containing mixed aqueous solution The salt such as nickel salt and cobalt salt used in the Ni / Co-containing mixed aqueous solution containing nickel and cobalt is not particularly limited as long as it is a water-soluble compound. Sulfates, nitrates, chlorides and the like can be used. For example, nickel sulfate or cobalt sulfate can be preferably used.

  The concentration of the metal salt in the Ni / Co-containing mixed aqueous solution is preferably 1 mol / L or more and 2.6 mol / L or less, more preferably 1 mol / L or more and 2.2 mol / L or less in total of the metal salts. . This is because when the metal salt concentration of the Ni / Co-containing mixed aqueous solution is 1 mol / L or more, the resulting nickel composite hydroxide slurry can have a sufficiently high slurry concentration. This is because an oxide can be generated. However, if the metal salt concentration of the Ni / Co-containing mixed aqueous solution exceeds 2.6 mol / L, crystal precipitation or freezing may occur at -5 ° C or lower, and the equipment piping may be clogged. This is not preferable because it requires cost and costs.

Furthermore, the amount of supplying the Ni / Co-containing mixed aqueous solution to the reaction vessel is not particularly limited, but for example, the crystallized product concentration at the time when the crystallization reaction is finished is adjusted to be 30 g / L or more and 250 g / L or less It is preferable to adjust the crystallized substance concentration to be 80 g / L or more and 150 g / L or less. This is because when the concentration of the crystallized product at the time when the crystallization reaction is finished is 30 g / L or more, the aggregation of the primary particles can be made to proceed particularly sufficiently, and should be 250 g / L or less. This is because the Ni / Co-containing mixed aqueous solution to be added can be sufficiently diffused in the reaction vessel to obtain a nickel composite hydroxide slurry having a particularly uniform composition.
(2) Ammonium ion supplier The ammonium ion supplier is not particularly limited as long as it is a water-soluble compound. For example, one kind selected from ammonia, ammonium sulfate, ammonium chloride, ammonium carbonate, ammonium fluoride, and the like. The above can be preferably used. In particular, one or more selected from ammonia and ammonium sulfate can be used more preferably.

  The ammonium ion donor can function as a complexing agent. Even if the pH value of the mixed aqueous solution is controlled within a wide range of 11.0 or more and 12.8 or less in the alkaline solution supply step to be described later by adding the ammonium ion supplier, the nickel composite hydroxide can be used. This is because the generation rate can be kept sufficiently high. In addition, even when the pH value of the mixed aqueous solution is controlled within the above range, when the obtained nickel composite hydroxide is filtered, the formation of fine particles that hinder the filtration is suppressed, and the nickel composite hydroxide is suppressed. This is because the secondary particles can be made into spherical particles.

  In the reaction vessel, the ammonia concentration in the initial aqueous solution and the mixed aqueous solution is preferably 3 g / L or more and 25 g / L or less.

  As described above, the ammonium ion supplier acts as a complexing agent and stabilizes the solubility of metal ions in the initial aqueous solution and the mixed aqueous solution by setting the ammonia concentration in the initial aqueous solution and the mixed aqueous solution to 3 g / L or more. And can be held constant. For this reason, primary particles of nickel composite hydroxide having a uniform shape and particle size can be formed. Furthermore, by setting the ammonia concentration to 3 g / L or more, it is possible to produce a nickel composite hydroxide containing secondary particles having an appropriate spread of particle size distribution suitable for use as a raw material for the positive electrode active material. .

  On the other hand, by setting the ammonia concentration in the initial aqueous solution and the mixed aqueous solution to 25 g / L or less, it is possible to prevent the solubility of metal ions from becoming too large, and the resulting nickel composite hydroxide has a composition shift. Can be prevented.

Note that the solubility of metal ions varies with the variation of the ammonia concentration in the initial aqueous solution and the mixed aqueous solution, and the uniformity of the composition inside the nickel composite hydroxide particles may be reduced. For this reason, it is preferable to control the fluctuation range of the ammonia concentration in the initial aqueous solution and the mixed aqueous solution to be small. For example, the ammonia concentration is more preferably controlled so that the range between the upper limit value and the lower limit value is 5 g / L and is within the range. Even in this case, the upper and lower limits of ammonia are preferably 3 g / L or more and 25 g / L or less.
(3) Aluminum source The aluminum source is not particularly limited, but it is preferable to use an aqueous sodium aluminate solution. The aqueous sodium aluminate solution can be obtained, for example, by dissolving a predetermined amount of sodium aluminate in water to obtain an aqueous solution, and adding a predetermined amount of sodium hydroxide. In order to uniformly disperse aluminum inside the nickel composite hydroxide particles, a mixed aqueous solution containing nickel and cobalt and a sodium aluminate aqueous solution may be added simultaneously to the reaction vessel. At this time, it is preferable to adjust the respective metal concentrations of nickel, cobalt, and aluminum so as to meet the target composition ratio indicated by the general formula of the nickel composite hydroxide.
(Alkaline solution supply step)
In the alkaline solution supply step, an alkaline solution, a Ni / Co-containing mixed aqueous solution, an ammonium ion supplier, an aluminum source, and the like can be continuously supplied to the initial aqueous solution to form a mixed aqueous solution.

  The alkaline solution used in the alkaline solution supply step is not particularly limited, but an aqueous solution of an alkali metal hydroxide is preferably used. As the alkali metal hydroxide, since it is easy to control the amount of addition, it is preferable to use a compound that is easily dissolved in water, for example, one or more selected from lithium hydroxide, sodium hydroxide, and potassium hydroxide. It is preferable.

  In the alkaline solution supply step, the method of adding the alkaline solution to the reaction vessel is not particularly limited, and it is preferable to add the alkaline solution with a pump capable of controlling the flow rate such as a metering pump. In addition, when adding an alkaline solution, it is preferable to add so that pH value of mixed aqueous solution may be hold | maintained at 11.0 or more and 12.8 or less on the basis of liquid temperature of 25 degreeC.

  In the alkaline solution supply step, when supplying the Ni / Co-containing mixed aqueous solution and the aluminum source, the respective metal concentrations of nickel, cobalt, and aluminum in the mixed aqueous solution are the target indicated by the general formula of the nickel composite hydroxide. It is preferable to adjust so as to match the composition ratio.

  As the Ni / Co-containing mixed aqueous solution, ammonium ion supplier, and aluminum source added to the initial aqueous solution in the alkaline solution supplying step, the same materials as those described in the initial aqueous solution can be preferably used. Then, explanation is omitted.

  The temperature of the mixed aqueous solution in the alkaline solution supply step is not particularly limited, but is preferably 50 ° C. or higher and 80 ° C. or lower, for example.

Moreover, the manufacturing method of the nickel composite hydroxide of this embodiment can also have a drying process which dries the obtained nickel composite hydroxide cake after a washing | cleaning process.
[Drying process]
In the drying step, the nickel composite hydroxide cake obtained by the washing step can be dried. The nickel composite hydroxide cake can be made into powder by drying.

  The drying means used in the drying step is not particularly limited, and various drying means can be used. For example, a drying method such as hot air drying can be used, and as a drying equipment, a stationary dryer, a batch type or continuous type air dryer using hot air heated by steam or the like can be used. .

3. Positive electrode active material for nonaqueous electrolyte secondary battery A positive electrode active material for a nonaqueous electrolyte secondary battery can be produced using the nickel composite hydroxide described above as a precursor.

  The positive electrode active material of the present embodiment is made of a lithium nickel composite oxide composed of a hexagonal lithium-containing composite oxide having a layered structure. Since the lithium nickel composite oxide uses the nickel composite hydroxide described above as a precursor, the lithium nickel composite oxide has a predetermined composition and average particle size, and can have a predetermined particle size distribution. For this reason, the positive electrode active material of this embodiment is excellent in cycle characteristics and safety, and is suitable as a positive electrode material of a nonaqueous electrolyte secondary battery.

[composition]
The positive electrode active material of the present embodiment is made of lithium-nickel-cobalt-aluminum composite oxide, the composition has the general _{formula: Li t Ni 1-x-} y Co x Al y O 2 + β ( where in the formula, 0.97 ≦ t ≦ 1.20, 0.05 ≦ x ≦ 0.35, 0.01 ≦ y ≦ 0.2, x + y <0.4, −0.2 ≦ β ≦ 0.2. The

  In the positive electrode active material of this embodiment, the atomic ratio t of lithium preferably satisfies 0.97 ≦ t ≦ 1.20. By setting the lithium atomic ratio t to 0.97 or more, the reaction resistance of the positive electrode in a battery using the positive electrode active material can be sufficiently suppressed, so that the output of the battery can be particularly increased. However, when the atomic ratio t of lithium is greater than 1.20, the initial discharge capacity of a battery using the positive electrode active material may be reduced and the reaction resistance of the positive electrode may be increased. Accordingly, the atomic ratio t of lithium is preferably 0.97 ≦ t ≦ 1.20, and more preferably the lower limit of the atomic ratio t of lithium is 1.05 or more.

  By including cobalt in the positive electrode active material, good cycle characteristics can be obtained. This is because by replacing a part of nickel in the crystal lattice with cobalt, the expansion and contraction behavior of the crystal lattice due to lithium desorption due to charge / discharge can be reduced. The atomic ratio x of cobalt is preferably 0.05 ≦ x ≦ 0.35, and considering the improvement of battery characteristics and safety, 0.07 ≦ x ≦ 0.25 is more preferable, and 0.10 ≦ x. More preferably, ≦ 0.20.

  In the positive electrode active material, the atomic ratio y of aluminum to the atoms of all metals other than lithium is preferably 0.01 ≦ y ≦ 0.2, and more preferably 0.01 ≦ y ≦ 0.1. . By adding aluminum to the positive electrode active material, the durability and safety of the battery can be improved when used as the positive electrode active material of the battery. In particular, in the positive electrode active material, when aluminum is uniformly distributed inside the particles of the positive electrode active material, the entire particle can exert the effect of improving the durability and safety of the battery. Even if it exists, there exists an advantage that the bigger effect is acquired and the fall of battery capacity can be suppressed.

  As described above, in the positive electrode active material, the atomic ratio y of aluminum to atoms of all metals other than lithium is preferably 0.01 or more. This is because durability (cycle characteristics) and safety can be particularly improved when the atomic ratio y of aluminum to atoms of all metals other than lithium is 0.01 or more.

  Further, the atomic ratio y of aluminum to the atoms of all metals other than lithium in the positive electrode active material is preferably 0.2 or less. This is because, when the atomic ratio y of aluminum to the atoms of all metals other than lithium is 0.2 or less, when the positive electrode active material is used as a positive electrode material of a battery, the positive electrode active material is oxidized / reduced in the battery. This is because the metal element contributing to the reaction is particularly sufficiently contained, so that the battery capacity can be particularly increased, which is preferable.

  The positive electrode active material has inherited the properties of the above-described nickel composite hydroxide as a precursor, and the sulfate radical content is preferably 0.4% by mass or less, more preferably 0.3% by mass or less. In addition, the chlorine content is preferably 0.05% by mass or less, and more preferably 0.03% by mass or less.

  The average particle diameter of the positive electrode active material particles (secondary particles) is preferably 3 μm or more and 25 μm or less. By setting the average particle diameter of the positive electrode active material particles within the above range, the battery capacity per volume can be increased for the battery using the positive electrode active material, and the output characteristics of the battery can be made particularly good. it can.

  It is preferable that [(d90−d10) / average particle size], which is an index indicating the spread of the particle size distribution of the positive electrode active material, is greater than 0.55 and not greater than 1.20. By satisfying the range of [(d90-d10) / average particle diameter] of the positive electrode active material, a battery using this positive electrode active material for the positive electrode has a high capacity per unit weight or capacity per unit volume, Moreover, it is excellent in safety, and good cycle characteristics and battery output can be obtained.

4). Method for Producing Positive Electrode Active Material for Nonaqueous Electrolyte Secondary Battery Next, a configuration example of the method for producing the positive electrode active material of the present embodiment will be described.

  The method for producing the positive electrode active material of the present embodiment is not particularly limited as long as it is a production method that can be produced from the nickel composite hydroxide described above, but it is more reliable if the following method for producing a positive electrode active material is adopted. Since a positive electrode active material can be manufactured, it is preferable.

  The manufacturing method of the positive electrode active material of this embodiment can have the following processes.

A heat treatment process in which nickel composite hydroxide as a raw material for the positive electrode active material is heat treated.
A mixing step in which a nickel composite hydroxide subjected to heat treatment and a lithium compound are mixed to form a mixture.

  A firing step of firing the mixture formed in the mixing step.

  In addition, after a baking process, the baked fired material can also be crushed as needed (crushing process).

  Through the above steps, a lithium nickel composite oxide, that is, a positive electrode active material can be obtained. Hereinafter, each step will be described.

  In the heat treatment step, residual moisture of the nickel composite hydroxide can be removed, and the nickel composite hydroxide can be decomposed into a nickel composite oxide. The heat treatment temperature in the heat treatment step is not particularly limited, but the heat treatment temperature is preferably 300 ° C. or higher and 800 ° C. or lower. This is because moisture removal and decomposition of the nickel composite hydroxide can proceed sufficiently by setting the heat treatment temperature to 300 ° C. or higher. However, the heat treatment temperature is preferably 800 ° C. or lower from the viewpoint of suppressing aggregation of the produced nickel composite oxide due to sintering.

  In the heat treatment step, the atmosphere in which the heat treatment is performed is not particularly limited, and is preferably performed in an air stream that can be easily performed.

  In the mixing step, the nickel composite hydroxide after the heat treatment, that is, the nickel composite oxide and the lithium compound can be mixed.

  Although it does not specifically limit as a lithium compound used at a mixing process, For example, 1 or more types selected from lithium hydroxide, lithium nitrate, and lithium carbonate can be used preferably. This is because the above-described lithium compound is relatively easily available. In particular, in consideration of ease of handling and quality stability, it is more preferable to use lithium hydroxide as the lithium compound in the mixing step.

  The mixing means for mixing the nickel composite oxide and the lithium compound in the mixing step is not particularly limited. For example, various mixers generally used in the mixing process can be used. For example, one or more types selected from a shaker mixer, a Laedige mixer, a Julia mixer, a V blender, and the like can be used. When these mixers are used, it is preferable to select conditions so that the nickel composite oxide and the lithium compound can be sufficiently mixed to such an extent that the particles of nickel composite oxide and the like are not destroyed.

  In the firing step, the mixture formed in the mixing step can be fired. The firing temperature in the firing step is not particularly limited, but is preferably 700 ° C. or higher and 850 ° C. or lower, and more preferably 720 ° C. or higher and 820 ° C. or lower.

  This is because when the temperature at which the mixture formed in the mixing step is baked is 700 ° C. or higher, lithium can be sufficiently diffused in the mixture, and residual lithium and unreacted particles are prevented from remaining. In addition, the crystal structure of the obtained lithium nickel composite oxide can be sufficiently adjusted. For this reason, in the battery using the lithium nickel composite oxide which is the obtained positive electrode active material, sufficient battery characteristics can be exhibited.

  However, if the temperature for firing the mixture formed in the mixing step exceeds 850 ° C., aggregation of the resulting lithium nickel composite oxide may be promoted. For this reason, it is preferable that the upper limit of the temperature which bakes the mixture formed at the mixing process is 850 degrees C or less.

  In the firing step, the firing time for firing the mixture formed in the mixing step is not particularly limited, but for example, preferably 3 hours or more, and more preferably 6 hours or more. Although the upper limit of baking time is not specifically limited, For example, it is preferable to set it as 24 hours or less.

  This is because the lithium nickel composite oxide can be sufficiently generated by setting the firing time for firing the mixture formed in the mixing step to 3 hours or longer. That is, the reaction rate can be sufficiently increased.

  In the firing step, the atmosphere at the time of firing the mixture formed in the mixing step is preferably an oxidizing atmosphere, and particularly contains oxygen within a range of oxygen volume of 18 volume% to 100 volume%. It is more preferable that the atmosphere be

  In the method for producing a positive electrode active material as described above, since the raw material uses the above-described sulfate radical, which is an impurity, and a nickel composite hydroxide in which the content of chlorine is suppressed to be low, it is mixed with a lithium compound. When firing, the reaction with lithium is not inhibited, and the decrease in crystallinity of the lithium nickel composite oxide can be suppressed. Thereby, the positive electrode active material obtained by this method for producing a positive electrode active material has few impurities remaining inside and has high crystallinity. For this reason, the non-aqueous electrolyte secondary battery using the positive electrode active material has a higher battery capacity per unit weight and unit volume as a whole battery, higher capacity than before, and excellent safety. It can be set as a secondary battery.

5. Non-aqueous electrolyte secondary battery A configuration example of the non-aqueous electrolyte secondary battery of the present embodiment will be described.

  The non-aqueous electrolyte secondary battery of this embodiment can be a non-aqueous electrolyte secondary battery using the positive electrode active material described above. More specifically, the nonaqueous electrolyte secondary battery of the present embodiment can have a positive electrode using the positive electrode active material described above. The non-aqueous electrolyte secondary battery can be provided with a structure substantially similar to that of a general non-aqueous electrolyte secondary battery except that the positive electrode active material described above is used as the positive electrode material. .

  The nonaqueous electrolyte secondary battery of the present embodiment has a structure including a case, and a positive electrode, a negative electrode, a nonaqueous electrolyte solution, and a separator housed in the case.

  Specifically, the nonaqueous electrolyte secondary battery of the present embodiment can have a structure in which an electrode body impregnated with a nonaqueous electrolyte solution is sealed in a battery case. The electrode body here has a structure in which a positive electrode and a negative electrode are laminated via a separator, and can be impregnated with a non-aqueous electrolyte solution as described above. Hereinafter, each member which comprises a non-aqueous electrolyte secondary battery is demonstrated.

  The positive electrode is a sheet-like member. For example, a positive electrode mixture paste formed by mixing a positive electrode active material, a conductive material, and a binder is applied to the surface of a current collector made of aluminum foil and formed by drying. can do. Further, for example, a mixture of a positive electrode active material, a conductive material, and a binder can be formed, and dried as necessary to obtain a positive electrode.

  The negative electrode is a sheet-like member formed by applying a negative electrode mixture paste containing a negative electrode active material to the surface of a metal foil current collector such as copper and drying it. Moreover, lithium metal processed into a desired shape can also be used as the negative electrode.

  As the separator, for example, a thin film such as polyethylene or polypropylene and a film having many fine holes can be used. In addition, if it has a function of a separator, it will not specifically limit.

The nonaqueous electrolytic solution is obtained by dissolving a lithium salt as a supporting salt in an organic solvent. As the organic solvent, ethylene carbonate, propylene carbonate, diethyl carbonate and the like can be used. As the electrolyte salt, LiPF ₆ , LiBF ₄ , LiClO ₄ or the like can be used.

  The non-aqueous electrolyte secondary battery of the present embodiment has a positive electrode using a positive electrode active material having the above-described sulfate radical and a nickel composite hydroxide with suppressed chlorine content as a precursor. For this reason, the capacity | capacitance per unit weight as a whole battery and the capacity | capacitance per unit volume are high capacity | capacitance, irreversible capacity | capacitance is small, and it can be set as the safety | security high.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited to these Examples.

Here, first, an evaluation method of the nickel composite hydroxide obtained in this example and the comparative example will be described.
(Evaluation of composition of nickel composite hydroxide)
The composition of the nickel composite hydroxide was measured with a high frequency inductively coupled plasma (ICP) emission spectroscopic analyzer (ICPS-8100, manufactured by Shimadzu Corporation) after the sample was dissolved in nitric acid.
(Evaluation of sulfate radical content of nickel composite hydroxide)
The sulfate radical content was measured by measuring the content of sulfur element with an ICP emission spectroscopic analyzer (ICPS-8100, manufactured by Shimadzu Corporation) after dissolving the obtained nickel composite hydroxide in nitric acid. the amount of elemental sulfur was determined by converting the SO _4.

The sulfate radical content was evaluated by taking samples from arbitrary five locations for the nickel composite hydroxides obtained in the examples and comparative examples, and subjecting each sample to the above evaluation.
(Evaluation of chlorine content of nickel composite hydroxide)
Chlorine content was measured with an automatic titrator (Hiranuma Sangyo Co., Ltd., COM-1600).

In addition, the evaluation of chlorine content took the sample from arbitrary 5 places about the nickel composite hydroxide obtained by each Example and the comparative example, respectively, and used for the said evaluation about each sample.
(Evaluation of average particle size and particle size distribution of nickel composite hydroxide)
The secondary particles contained in the nickel composite hydroxide were measured for d10, d90, and average particle diameter using a laser light diffraction / scattering particle size analyzer (Model: MT3300EXII manufactured by Microtrack Bell Co., Ltd.).

  In addition, d10 means the particle size in which the cumulative volume becomes 10% of the total volume of all particles when the number of particles in each particle size is accumulated from the smaller particle size. Further, d90 means a particle size in which the cumulative volume becomes 90% of the total volume of all particles when the number of particles in each particle size is accumulated from the smallest particle size.

Moreover, (d90-d10) / average particle diameter was computed from the measured value.
(Evaluation method of battery characteristics)
In evaluating the battery characteristics, a lithium nickel composite oxide as a positive electrode active material was generated from the nickel composite hydroxide produced in each of the examples and comparative examples. A method for producing the lithium nickel composite oxide will be described below.

  The nickel composite hydroxide produced in Examples and Comparative Examples was heat-treated at a temperature of 700 ° C. for 6 hours in an air stream having an oxygen content of 21% by volume to recover the nickel composite oxide (heat treatment step).

  Subsequently, lithium hydroxide was weighed so that Li / Me = 1.025 and mixed with the recovered nickel composite oxide to form a mixture (mixing step). In addition, Me of said Li / Me means the sum total of metals other than lithium in a mixture, ie, nickel, cobalt, and aluminum. Mixing was performed using a shaker mixer apparatus (TURBULA Type T2C manufactured by Willy et Bacofen (WAB)).

  Next, the mixture obtained in the mixing step was calcined at 500 ° C. for 4 hours in an oxygen stream having an oxygen content of 100% by volume, and then calcined at 730 ° C. for 24 hours (firing step).

  After firing, the product was cooled to room temperature, and the recovered product was crushed (crushing step).

  Through the above steps, a lithium nickel composite oxide as a positive electrode active material was obtained.

  Next, a non-aqueous electrolyte secondary battery was produced using the obtained lithium nickel composite oxide.

  According to the above-described procedure, 70% by mass of the positive electrode active material powder obtained from the nickel composite hydroxide prepared in each example and comparative example, 20% by mass of acetylene black as a conductive material, and PTFE ( (Polytetrafluoroethylene) was added and mixed in an amount of 10% by mass, and 150 mg was taken out from this to produce a pellet to obtain a positive electrode.

  Lithium metal was used as the negative electrode.

As the non-aqueous electrolyte solution, an equivalent mixed solution (manufactured by Toyama Pharmaceutical Co., Ltd.) of ethylene carbonate (EC) and diethyl carbonate (DEC) using 1M LiClO ₄ as a supporting salt was used.

  Then, a 2032 type coin battery was fabricated using each of the above members in an Ar atmosphere glove box whose dew point was controlled at −80 ° C.

  About the produced coin battery, initial stage discharge capacity was evaluated and initial stage efficiency was computed.

The produced coin battery is left for about 24 hours, and after the open circuit voltage OCV (open circuit voltage) is stabilized, the current density with respect to the positive electrode is set to 0.5 mA / cm ² and charged to a cutoff voltage of 4.3 V to obtain an initial charge capacity. did. And the capacity | capacitance when it discharged to the cut-off voltage 3.0V after the rest for 1 hour was made into the initial stage discharge capacity. The initial efficiency was calculated as initial discharge capacity / initial charge capacity × 100 (%).

  In Examples and Comparative Examples, a special grade reagent manufactured by Wako Pure Chemical Industries, Ltd. is used for each sample for the production of nickel composite hydroxide.

Below, the manufacturing conditions of the nickel composite hydroxide of each Example and a comparative example are demonstrated.
[Example 1]
The following coprecipitation step was performed to produce a nickel composite hydroxide.

  Ni / Co-containing mixed aqueous solution containing nickel sulfate and cobalt chloride, 25% by mass of ammonia water, and aluminium so that the molar ratio of nickel: cobalt: aluminum is 81.5: 15.0: 3.5. A sodium acid aqueous solution was simultaneously added to the reaction vessel to prepare an initial aqueous solution (initial aqueous solution preparation step). In addition, the density | concentration of the metal salt of Ni / Co containing mixed aqueous solution of nickel sulfate and cobalt chloride was 2.0 mol / L.

  Then, with respect to the initial aqueous solution, while controlling the pH to 11.8 on the basis of the liquid temperature of 25 ° C., the reaction temperature to 50 ° C., and the ammonia concentration to be kept at 10 g / L, Ni / Co containing mixed aqueous solution, 25 mass% ammonia water, and sodium aluminate aqueous solution were added (alkaline solution supply step).

  At this time, the Ni / Co-containing mixed aqueous solution and sodium aluminate were added so that the molar ratio of nickel, cobalt, and aluminum in the obtained mixed aqueous solution maintained the molar ratio in the initial aqueous solution.

  By carrying out the coprecipitation step having the initial aqueous solution preparation step and the alkaline solution supply step, nickel composite hydroxide (nickel cobalt aluminum composite) composed of spherical secondary particles in which plate-like primary particles are aggregated. Hydroxide). After the inside of the reaction vessel was stabilized, the nickel composite hydroxide slurry was recovered from the overflow port.

  Next, the obtained nickel composite hydroxide slurry 40L having a slurry concentration of 100 g / L is used as a pressing means in a filter press (Nippon Filtration Equipment Co., Ltd. model: PFS-0.48-25) as a pressing means. It supplied via the connected supply piping (supply process).

  Next, the nickel composite hydroxide slurry was filtered using a filter press as a pressing means to obtain a nickel composite hydroxide cake (filtration step).

  And the nickel composite hydroxide cake was wash | cleaned and filtered with the following procedures (washing | cleaning process).

  The pressure of the pressure by the filter press is 0.4 MPa, and the temperature of the alkaline liquid as the cleaning liquid is 25 ° C. and 1.0 mol through the cleaning liquid pipe connected to the filter press while pressing the nickel composite hydroxide cake. 8 L of / L sodium carbonate aqueous solution was supplied. The alkaline liquid as the cleaning liquid was supplied over 0.3 hours. Thereby, the nickel composite hydroxide cake was washed (first washing step).

  After completion of the first washing step, the squeezing by the filter press was temporarily stopped.

  Next, in a state where the nickel composite hydroxide cake has not been squeezed, the liquid temperature which is an alkaline liquid as a cleaning liquid is 25 ° C., 1.0 mol / 1 L of sodium carbonate aqueous solution was supplied. The alkaline liquid as the cleaning liquid was supplied over 0.1 hour.

  In addition, after supplying the alkaline liquid, 9 L of pure water was supplied as washing water to the supply pipe. Thereafter, the cake was dehydrated by flowing air for 20 minutes while re-pressing the cake again at 0.7 MPa (second washing step).

  The obtained nickel composite hydroxide cake was dried at 120 ° C. for 15 hours by a stationary dryer to obtain a nickel composite hydroxide.

  The obtained nickel composite hydroxide was evaluated as described above. The evaluation results are shown in Table 1.

In addition, the evaluation of the sulfate content of the nickel composite hydroxide and the evaluation of the chlorine content were carried out by collecting samples from any five locations of the nickel composite hydroxide obtained as described above. . However, the evaluation results of the sulfate radical content and the chlorine content are the same in the evaluation results of the five samples, and only one value is shown in Table 1. The same applies to Examples 2 to 11.
[Example 2]
In the first washing step, a nickel composite hydroxide was produced in the same manner as in Example 1 except that the pressing pressure of the nickel composite hydroxide cake was 0.2 MPa, and the above-described evaluation was performed. The evaluation results are shown in Table 1.
[Example 3]
In the first washing step, a nickel composite hydroxide was produced in the same manner as in Example 1 except that the pressing pressure of the nickel composite hydroxide cake was 0.5 MPa, and the above-described evaluation was performed. The evaluation results are shown in Table 1.
[Example 4]
In the second washing step, a nickel composite hydroxide was produced in the same manner as in Example 1 except that the recompression pressure of the nickel composite hydroxide cake was 0.5 MPa, and the above-described evaluation was performed. The evaluation results are shown in Table 1.
[Example 5]
In the first washing step, a nickel composite hydroxide was produced in the same manner as in Example 1 except that the pressing pressure of the nickel composite hydroxide cake was 0.1 MPa, and the above-described evaluation was performed. The evaluation results are shown in Table 1.
[Example 6]
In the first washing step, except that the pressing pressure of the nickel composite hydroxide cake was 0.7 MPa, and in the second cleaning step, the recompression pressure of the nickel composite hydroxide cake was 0.8 MPa. A nickel composite hydroxide was produced in the same manner as in Example 1, and the above-described evaluation was performed. The evaluation results are shown in Table 1.
[Example 7]
In the first cleaning step, except that the pressing pressure of the nickel composite hydroxide cake was 0.7 MPa, and in the second cleaning step, the re-pressing pressure of the nickel composite hydroxide cake was 0.4 MPa. A nickel composite hydroxide was produced in the same manner as in Example 1, and the above-described evaluation was performed. The evaluation results are shown in Table 1.
[Example 8]
In the first cleaning step, except that the pressing pressure of the nickel composite hydroxide cake was 0.2 MPa, and in the second cleaning step, the re-pressing pressure of the nickel composite hydroxide cake was 0.3 MPa. A nickel composite hydroxide was produced in the same manner as in Example 1, and the above-described evaluation was performed. The evaluation results are shown in Table 1.
[Example 9]
In the coprecipitation step, the supply rate of each supply liquid is reduced from that in Example 1, which is an index indicating the spread of the particle size distribution of the obtained nickel composite hydroxide [(d90-d10) / average particle Nickel composite hydroxide was prepared in the same manner as in Example 1 except that the [diameter] was 0.61, and the above-described evaluation was performed.

The evaluation results are shown in Table 1.
[Example 10]
In the coprecipitation step, the feed rate of each feed solution is increased from that in Example 1, which is an index indicating the spread of the particle size distribution of the obtained nickel composite hydroxide [(d90-d10) / average particle Nickel composite hydroxide was prepared in the same manner as in Example 1 except that the [diameter] was 1.18, and the above-described evaluation was performed.

The evaluation results are shown in Table 1.
[Example 11]
In the first washing step and the second washing step, nickel composite water is used in the same manner as in Example 1 except that a potassium carbonate aqueous solution having an alkaline liquid temperature of 25 ° C. and 1.0 mol / L is used as the washing liquid. An oxide was prepared and evaluated as described above.

  In the first cleaning step, 8 L of the potassium carbonate aqueous solution was supplied, and in the second cleaning step, 1 L of the potassium carbonate aqueous solution was supplied.

The evaluation results are shown in Table 1.
[Comparative Example 1]
The second washing step was not carried out. After the first washing step was completed, the cake was depressurized by flowing air for 20 minutes while continuing to re-press the cake at 0.7 MPa. A nickel composite hydroxide was produced in the same manner as in Example 1, and the above-described evaluation was performed. The evaluation results are shown in Table 1.

  The evaluation of the sulfate content of the nickel composite hydroxide and the evaluation of the chlorine content were carried out by collecting samples from any of the five nickel composite hydroxides obtained as described above. Table 1 shows the evaluation results of the lowest sulfate group content and chlorine content.

得られたニッケル複合水酸化物については、既述のニッケル複合水酸化物の組成の評価を実施したところ、実施例１〜１１、及び比較例１のいずれについても、Ｎｉ_{０．８１５}Ｃｏ_０．１５Ａｌ_{０．０３５}（ＯＨ）_２の組成になっていることが確認できた。

The obtained nickel composite hydroxide was evaluated for the composition of the nickel composite hydroxide described above _{. As a result} , for both Examples 1 to 11 and Comparative Example 1, Ni _0.815 Co _0. It was confirmed that the composition was ₁₅ Al _0.035 (OH) ₂ .

  In Examples 1 to 11, when the cross section of the obtained nickel composite hydroxide was observed with a scanning electron microscope, a plurality of plate-like primary particles aggregated to form spherical secondary particles. It was confirmed that

  According to the results shown in Table 1, in Examples 1 to 11, the sulfate content of the nickel composite hydroxide is 0.4% by mass or less, and the chlorine content is 0.05% by mass or less. Met. Moreover, it has also confirmed that the content of sulfate radicals and chlorine could be suppressed uniformly low.

  For this reason, the initial discharge capacity of the non-aqueous electrolyte secondary battery using the positive electrode active material obtained from the nickel composite hydroxide of Examples 1 to 11 is 180 mAh / g or more, and the initial efficiency is 85% in all cases. From the above, it was confirmed that the battery capacity was high.

  On the other hand, in Comparative Example 1 in which the second washing step was not performed, the sulfate radical was 0.42% by mass and chlorine was 0.09% by mass. Moreover, in the same sample, the sulfate radicals and the chlorine content varied, confirming that they were not uniform. Specifically, in Comparative Example 1, the evaluation results of the sulfate radical content and the chlorine content of the five samples that were evaluated had a maximum value and a minimum value of ± 20% of the median value, respectively. It was confirmed that the range was exceeded.

  And the initial discharge capacity of the nonaqueous electrolyte secondary battery using the positive electrode active material obtained from the nickel composite hydroxide of Comparative Example 1 is 173 mAh / g, and the initial efficiency is 83% in all cases. It was confirmed that the value was lower than that of Example 11.

Claims (6)

Formula _{Ni 1-x-y Co x} Al y (OH) 2 + α (0.05 ≦ x ≦ 0.35,0.01 ≦ y ≦ 0.2, x + y <0.4, -0.2 ≦ α ≦ 0.2),
Containing spherical secondary particles formed by aggregation of a plurality of primary particles,
The secondary particles have an average particle size of 3 μm or more and 20 μm or less, and the secondary particles are an index indicating the spread of the particle size distribution [(d90−d10) / average particle size] larger than 0.55. 20 or less,
A nickel composite hydroxide having a sulfate radical content of 0.4 mass% or less and a chlorine content of 0.05 mass% or less. Supplying a nickel composite hydroxide slurry into the squeezing means via a supply pipe;
The nickel composite hydroxide slurry is filtered by the squeezing means, and the nickel composite hydroxide cake is filtered.
A washing step of washing the nickel composite hydroxide cake in the pressing means,
The washing step includes
An alkaline liquid is supplied to the nickel composite hydroxide cake through a cleaning liquid pipe connected to the pressing means in a state where the nickel composite hydroxide cake is compressed by the pressing means, and the nickel composite hydroxide is supplied. A first washing step for washing the cake;
The 2nd washing | cleaning step which supplies an alkaline liquid in the said pressing means via the said supply piping in the state which is not pressing the said nickel composite hydroxide cake, and re-presses the said nickel composite hydroxide cake after that And a method for producing a nickel composite hydroxide.   The method for producing a nickel composite hydroxide according to claim 2, wherein the alkaline liquid is at least one aqueous solution selected from sodium carbonate, potassium carbonate, sodium sesquicarbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, and sodium hydroxide. . In the first washing step, the pressing pressure when pressing the nickel composite hydroxide cake is:
The manufacturing method of the nickel composite hydroxide of Claim 2 or 3 lower than the re-pressing pressure at the time of re-pressing the said nickel composite hydroxide cake in a said 2nd washing | cleaning step.   The nickel composite hydroxide according to any one of claims 2 to 4, wherein in the first cleaning step, a pressing pressure when the nickel composite hydroxide cake is squeezed is 0.2 MPa or more and 0.5 MPa or less. Manufacturing method.   The nickel composite water according to any one of claims 2 to 5, wherein in the second cleaning step, a re-pressing pressure when the nickel composite hydroxide cake is re-pressed is 0.25 MPa or more and 0.8 MPa or less. Production method of oxide.