JP2019133881A - Positive electrode active material for lithium ion battery, lithium ion battery, and manufacturing method of positive electrode active material for lithium ion battery - Google Patents

Abstract

To provide a positive electrode active material for a lithium ion battery having good battery characteristics.SOLUTION: A positive electrode active material for a lithium ion battery is represented by a composition formula of LiNiCoMnO(in the above formula, 1.00≤a≤1.02, 0.85≤b≤0.9, 0.07≤c≤0.12, 0.01≤d≤0.05, and b+c+d=1) and has α×β×γ of 3 to 6 and a primary particle aspect ratio of 1 to 4 when a specific surface area is α (m/g), 1500 times tap density is β (g/cc), 10% volume diameter (D10) is γ (μm).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a positive electrode active material for a lithium ion battery, a lithium ion battery, and a method for producing a positive electrode active material for a lithium ion battery.

Currently used lithium ion batteries include a layered compound LiMeO ₂ as a positive electrode active material (Me is a cation selected to be trivalent on average, and always contains a redox cation), a spinel compound LiMe ₂ O ₄ ( Hereinafter, Me is the same as described above), olivine LiMeXO ₄ (X is a cation selected so as to have a valence of + V), fluorite type compound Li ₅ MeO _{4, and the} like can be taken out per mass of the positive electrode active material. As for the amount of electricity, a value of approximately 100 to 250 mAh / g has been proposed.

However, positive electrode active materials that can stably extract 200 mAh / g are limited, and high such as LiNi _a Co _b Mn _c O ₂ (0.7 ≦ a <1, a + b + c = 1) Such as those with Ni composition (commonly called high nickel) or xLi ₂ MnO _3- (1-x) LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (0 <x <1) There is only such a solid solution. Among these, high nickel is attracting a great deal of attention in that the electrode packing density can be increased to a level equivalent to that of a LiCoO ₂ positive electrode active material conventionally used.

When this high nickel is manufactured, as described in paragraphs 0141 to 0144 of Patent Document 1, for example, it is common to fire in an oxygen atmosphere. This is because when Ni ²⁺ in nickel cobalt manganese composite hydroxide particles is oxidized to Ni ³⁺ during firing, in addition to the stoichiometric amount of oxygen necessary for oxidation, the generated Ni ³⁺ is This is to ensure the oxygen partial pressure necessary to maintain the valence.

As described in Patent Document 1, the positive electrode active material containing Ni ³⁺ thus produced can produce a battery exhibiting very good rate characteristics by adjusting the surface coating and powder physical properties. .

Japanese Patent No. 6026679

  However, in Patent Document 1, a high-capacity and high-power positive electrode active material is obtained by adjusting values obtained by dividing the surface coating, the average secondary particle diameter, the BET specific surface area, and the heavy density by the light density. Careful adjustment reduces the degree of freedom in battery design, and the capacity that was originally considered to be high depending on conditions may be reduced, which may adversely affect battery characteristics.

  This invention makes it a subject to provide the positive electrode active material for lithium ion batteries with favorable battery characteristics.

In one embodiment of the present invention completed based on the above knowledge, a composition formula: Li _a Ni _b Co _c Mn _d O ₂
(In the above formula, 1.00 ≦ a ≦ 1.02, 0.85 ≦ b ≦ 0.9, 0.07 ≦ c ≦ 0.12, 0.01 ≦ d ≦ 0.05, b + c + d = 1)
When the specific surface area is α (m ² / g), the 1500 times tap density is β (g / cc), and the 10% volume diameter (D10) is γ (μm), α × β × γ is It is a positive electrode active material for lithium ion batteries having a primary particle aspect ratio of 1 to 4 and 3 to 6.

In another embodiment, the present invention is a positive electrode active material having a core particle and a coating provided on the surface of the core particle,
Composition _{formula: Li a Ni b Co c Mn} d Mz e O 2
(In the above formula, 1.004 ≦ a ≦ 1.02, 0.85 ≦ b ≦ 0.9, 0.07 ≦ c ≦ 0.12, 0.01 ≦ d ≦ 0.05, 0 ≦ e ≦ 0.005, b + c + d = 1, Mz is W, Ti, Zr At least one selected from)
When the specific surface area is α (m ² / g), the 1500 times tap density is β (g / cc), and the 10% volume diameter (D10) is γ (μm), α × β × γ is 3 to 6, the aspect ratio of primary particles is 1 to 4, and the coating film is a positive electrode active material for a lithium ion battery that is formed of particles containing Mz and is formed in an island shape.

  In yet another embodiment, the positive electrode active material for a lithium ion battery of the present invention has a median diameter of 3 to 15 μm.

In still another embodiment of the present invention, the positive electrode active material (positive electrode active material A) and a composition formula: Li _a Ni _b Co _c Mn _d O ₂
(In the above formula, 1.00 ≦ a ≦ 1.02, 0.80 ≦ b <0.85, 0.10 <c ≦ 0.15, 0.01 ≦ d ≦ 0.05, b + c + d = 1), and the specific surface area is α (m ² / g ), When 1500 times tap density is β (g / cc) and 10% volume diameter (D10) is γ (μm), α × β × γ is 3 to 6, and the aspect ratio of primary particles is 1 It is the positive electrode active material for lithium ion batteries formed by mixing the positive electrode active material B which is -4.

  In still another embodiment of the positive electrode active material for a lithium ion battery of the present invention, the positive electrode active material B has a median diameter of 3 to 8 μm.

  In yet another embodiment, the positive electrode active material for a lithium ion battery of the present invention is obtained by mixing the positive electrode active material A and the positive electrode active material B in a mass ratio of 10:90 to 90:10.

In yet another embodiment of the present invention, a positive electrode active material having the positive electrode active material A of the present invention, a core particle and a coating provided on the surface of the core particle,
Composition _{formula: Li a Ni b Co c Mn} d Mz e O 2
(In the above formula, 1.004 ≦ a ≦ 1.02, 0.80 ≦ b <0.85, 0.10 <c ≦ 0.15, 0.01 ≦ d ≦ 0.05, 0 ≦ e ≦ 0.015, b + c + d = 1, Mz is W, Ti, Zr When the specific surface area is α (m ² / g), the 1500 times tap density is β (g / cc), and the 10% volume diameter (D10) is γ (μm) In addition, α × β × γ is 3 to 6, the aspect ratio of primary particles is 1 to 4, and the coating is made of particles containing Mz and is formed in an island shape. It is a positive electrode active material for lithium ion batteries formed by mixing the substance C.

  In still another embodiment of the positive electrode active material for a lithium ion battery of the present invention, the positive electrode active material C has a median diameter of 3 to 8 μm.

  In still another embodiment, the positive electrode active material for a lithium ion battery of the present invention is obtained by mixing the positive electrode active material A and the positive electrode active material C in a mass ratio of 10:90 to 90:10.

  In yet another embodiment, the present invention is a lithium ion battery including a positive electrode including the positive electrode active material for a lithium ion battery of the present invention, a negative electrode, and an electrolyte containing an electrolytic solution or a solid electrolyte.

  In yet another embodiment of the present invention, the positive electrode active material for a lithium ion battery of the present invention or a method for producing the positive electrode active material B, the true density is 3.7 to 3.8 g / cc, A step of dry-mixing nickel cobalt manganese hydroxide powder having a tap density of 1.3 to 1.9 g / cc with lithium hydroxide, and the powder obtained by dry-mixing the powder in an oxygen atmosphere at 400 to 500 ° C. The method for producing a positive electrode active material for a lithium ion battery includes a step of firing at 700 to 800 ° C. after firing without cooling and heating.

In yet another embodiment of the present invention, the positive electrode active material for a lithium ion battery of the present invention or a method for producing the positive electrode active material C, the true density is 3.7 to 3.8 g / cc, A step of dispersing nickel cobalt manganese hydroxide particles having a tap density of 1.3 to 1.9 g / cc in water to form a slurry; at least one median selected from the group consisting of TiO ₂ , ZrO ₂ , and WO ₃ A step of adding particles having a diameter of 0.1 to 0.8 μm to the slurry and spray-drying, a step of dry-mixing the spray-dried product generated by the spray-drying with lithium hydroxide, and a powder obtained by the dry-mixing This is a method for producing a positive electrode active material for a lithium ion battery, comprising a step of firing the body at 400 to 500 ° C. in an oxygen atmosphere, raising the temperature without cooling, and further firing at 700 to 800 ° C.

  ADVANTAGE OF THE INVENTION According to this invention, the positive electrode active material for lithium ion batteries with a favorable battery characteristic can be provided.

It is a schematic diagram of an electrolytic oxidation apparatus. 4 is a SEM image of Example 3.

[Positive electrode active material for lithium ion battery according to Embodiment 1]
The positive electrode active material for a lithium ion battery according to Embodiment 1 of the present invention has a composition formula: Li _a Ni _b Co _c Mn _d O ₂
(In the above formula, 1.00 ≦ a ≦ 1.02, 0.85 ≦ b ≦ 0.9, 0.07 ≦ c ≦ 0.12, 0.01 ≦ d ≦ 0.05, b + c + d = 1), and the specific surface area is α (m ² / g ), When 1500 times tap density is β (g / cc) and 10% volume diameter (D10) is γ (μm), α × β × γ is 3 to 6, and the aspect ratio of primary particles is 1 ~ 4.

The positive electrode active material for a lithium ion battery according to Embodiment 1 of the present invention has a specific surface area of α (m ² / g), a 1500 times tap density of β (g / cc), and a 10% volume diameter (D10) of γ (μm ), Α × β × γ is controlled to be 3-6. α × β represents the total surface area of the positive electrode active material in a tapped volume. By controlling α × β × γ, which is obtained by multiplying α × β by γ, which is the 10% volume diameter (D10) of the positive electrode active material, to 3 to 6, while maintaining good filling properties of the positive electrode active material Thus, the spread of the particle size distribution can be suppressed, and battery characteristics such as discharge capacity and cycle characteristics are improved.

  Since the positive electrode active material for a lithium ion battery according to Embodiment 1 of the present invention includes primary particles and secondary particles, and the aspect ratio of the primary particles is controlled to be as small as 1 to 4, the positive electrode active material particles are heavy. As a result, the direct current resistance can be reduced as a result of improving the electronic conductivity in the positive electrode active material. The aspect ratio of the primary particles may be 1.2 or more, 1.4 or more, 3.5 or less, or 2.5 or less.

  The median diameter of the positive electrode active material for a lithium ion battery according to Embodiment 1 of the present invention is preferably 3 to 15 μm. When the median diameter is smaller than 3 μm, the unevenness of the positive electrode active material particles may be increased, and such a positive electrode active material particle may take up a large amount of solvent during the electrode preparation, which may make the electrode preparation difficult. In addition, there is a possibility that the positive electrode active material may be peeled off from the current collector when the battery is used. If the median diameter is larger than 15 μm, the movement of lithium ions in the electrode during charging / discharging may take a long distance, and the required output may not be obtained depending on the operating current value, and the cathode active material particles themselves may crack. May be easier.

[Positive electrode active material for lithium ion battery according to Embodiment 2]
The positive electrode active material for a lithium ion battery according to Embodiment 2 of the present invention is a positive electrode active material having a core particle and a coating provided on the surface of the core particle,
Composition _{formula: Li a Ni b Co c Mn} d Mz e O 2
(In the above formula, 1.004 ≦ a ≦ 1.02, 0.85 ≦ b ≦ 0.9, 0.07 ≦ c ≦ 0.12, 0.01 ≦ d ≦ 0.05, 0 ≦ e ≦ 0.005, b + c + d = 1, Mz is W, Ti, Zr When the specific surface area is α (m ² / g), the 1500 times tap density is β (g / cc), and the 10% volume diameter (D10) is γ (μm) In addition, α × β × γ is 3 to 6, the aspect ratio of the primary particles is 1 to 4, and the coating is composed of particles containing Mz and is formed in an island shape.

The positive electrode active material for a lithium ion battery according to Embodiment 2 of the present invention has a specific surface area of α (m ² / g), a 1500 times tap density of β (g / cc), and a 10% volume diameter (D10) of γ (μm ), Α × β × γ is controlled to be 3-6. α × β represents the total surface area of the positive electrode active material in a tapped volume. By controlling α × β × γ, which is obtained by multiplying α × β by γ, which is the 10% volume diameter (D10) of the positive electrode active material, to 3 to 6, while maintaining good filling properties of the positive electrode active material Thus, the spread of the particle size distribution can be suppressed, and battery characteristics such as discharge capacity and cycle characteristics are improved.

  Since the positive electrode active material for a lithium ion battery according to Embodiment 2 of the present invention includes primary particles and secondary particles, and the aspect ratio of the primary particles is controlled to be as small as 1 to 4, the positive electrode active material particles are heavy. As a result, the direct current resistance can be reduced as a result of improving the electronic conductivity in the positive electrode active material. The aspect ratio of the primary particles may be 1.2 or more, 1.4 or more, 3.5 or less, or 2.5 or less.

  In Patent Document 1 described above, an additive that does not directly contribute to charge / discharge is coated on the entire surface of the positive electrode active material particles (coating layer), whereas the positive electrode active for a lithium ion battery according to Embodiment 2 of the present invention. In the substance, the coating is composed of particles containing Mz (at least one selected from W, Ti, and Zr) and is formed in an island shape. Therefore, according to the positive electrode active material for a lithium ion battery according to Embodiment 2 of the present invention, it is possible to reduce the amount of the additive that does not directly contribute to charging / discharging, and therefore, the discharge capacity and cycle characteristics are high in output. It becomes good.

  The median diameter of the positive electrode active material for a lithium ion battery according to Embodiment 2 of the present invention is preferably 3 to 15 μm. When the median diameter is smaller than 3 μm, the unevenness of the positive electrode active material particles may be increased, and such a positive electrode active material particle may take up a large amount of solvent during the electrode preparation, which may make the electrode preparation difficult. In addition, there is a possibility that the positive electrode active material may be peeled off from the current collector when the battery is used. If the median diameter is larger than 15 μm, the movement of lithium ions in the electrode during charging / discharging may take a long distance, and the required output may not be obtained depending on the operating current value, and the cathode active material particles themselves may crack. May be easier.

[Positive electrode active material for lithium ion battery according to Embodiment 3]
The positive electrode active material for a lithium ion battery according to Embodiment 3 of the present invention includes a positive electrode active material (referred to as positive electrode active material A) according to Embodiment 1 or 2, and a composition formula: Li _a Ni _b Co _c Mn _d O ₂
(In the above formula, 1.00 ≦ a ≦ 1.02, 0.80 ≦ b <0.85, 0.10 <c ≦ 0.15, 0.01 ≦ d ≦ 0.05, b + c + d = 1), and the specific surface area is α (m ² / g ), When 1500 times tap density is β (g / cc) and 10% volume diameter (D10) is γ (μm), α × β × γ is 3 to 6, and the aspect ratio of primary particles is 1 It mixes with the positive electrode active material B which is -4. Since the positive electrode active material A is superior in discharge capacity and the positive electrode active material B is excellent in cycle characteristics, a good volume energy density and cycle characteristics can be realized by this mixing.

  The median diameter of the positive electrode active material B for a lithium ion battery is preferably 3 to 8 μm. This is because the positive electrode active material A is superior in discharge capacity, and it is better to use a relatively large particle diameter from the viewpoint of improving the volume energy density when blending, whereas the positive electrode active material B has a cycle characteristic. Since it is excellent, it is better to use a relatively small particle diameter because it is better to reduce the movement distance of lithium ions during charging and discharging.

  In the positive electrode active material for a lithium ion battery according to Embodiment 3 of the present invention, the positive electrode active material A and the positive electrode active material B are preferably mixed in a mass ratio of 10:90 to 90:10. According to such a configuration, the output may be improved in addition to the cycle characteristics.

[Positive electrode active material for lithium ion battery according to Embodiment 4]
A positive electrode active material for a lithium ion battery according to Embodiment 4 of the present invention is a positive electrode active material having positive electrode active material A according to Embodiment 1 or 2, core particles and a coating provided on the surface of the core particles. composition _{formula: Li a Ni b Co c Mn} d Mz e O 2
(In the above formula, 1.004 ≦ a ≦ 1.02, 0.80 ≦ b <0.85, 0.10 <c ≦ 0.15, 0.01 ≦ d ≦ 0.05, 0 ≦ e ≦ 0.015, b + c + d = 1, Mz is W, Ti, Zr When the specific surface area is α (m ² / g), the 1500 times tap density is β (g / cc), and the 10% volume diameter (D10) is γ (μm) In addition, α × β × γ is 3 to 6, the primary particles have an aspect ratio of 1 to 4, the coating is composed of particles containing Mz, and is formed in an island shape. Mixed. Since the positive electrode active material A is superior in discharge capacity and the positive electrode active material C is superior in cycle characteristics, a good volume energy density and cycle characteristics can be realized by this mixing.

  The median diameter of the positive electrode active material C for a lithium ion battery is preferably 3 to 8 μm. This is because the positive electrode active material A is superior in discharge capacity, and it is better to use a relatively large particle diameter from the viewpoint of improving the volume energy density when blending, whereas the positive electrode active material C has a cycle characteristic. Since it is excellent, it is better to use a relatively small particle diameter because it is better to reduce the movement distance of lithium ions during charging and discharging.

  In the positive electrode active material for a lithium ion battery according to Embodiment 4 of the present invention, the positive electrode active material A and the positive electrode active material C are preferably mixed at a mass ratio of 10:90 to 90:10. According to such a configuration, the output may be improved in addition to the cycle characteristics.

[Method for Producing Cathode Active Material for Lithium Ion Battery According to Embodiments 1 to 4 of the Present Invention]
Next, an embodiment of a method for producing positive electrode active materials A to C for lithium ion batteries according to Embodiments 1 to 4 of the present invention will be described in detail. First, an aqueous transition metal solution in which nickel sulfate, cobalt sulfate, and manganese sulfate are dissolved, an aqueous caustic soda solution (hereinafter sometimes referred to as “caustic”), an aqueous ammonia solution (hereinafter sometimes referred to as “anhydrous”). These are prepared and charged into one reaction vessel or a reaction vessel in the reaction apparatus to form a slurry containing transition metal hydroxide (hereinafter, sometimes referred to as “precursor”) particles. Under the present circumstances, you may react, making it circulate between crossflow filtration apparatuses.

  At this time, it is preferable to produce the precursor powder so that the true density is 3.7 to 3.8 g / cc and the tap density is 1.3 to 1.9 g / cc. There is no particular method for obtaining these precursor powders, and this can be achieved by selecting production conditions suitable for the above from known crystallization methods. In the production of the precursor particles, in addition to the above transition metal aqueous solution / caustic / aqueous solution, an aqueous solution of guanidine or guanidine derivative (L-arginine ethyl ester sulfate, agmatine sulfate, etc.) (hereinafter referred to as `` G (Sometimes referred to as “liquid”).

  The obtained precursor particles are filtered, washed with water by a known method, and dried. These precursor particles may be dispersed in pure water, and oxides of Ti, Zr, and W may be added and dispersed therein as an additive, and spray dried using a micromist dryer or the like. At this time, Ti, Zr, and W oxides adhere to the surface of the precursor (hereinafter, sometimes referred to as “coating precursor”). In this case, it is preferable to use an oxide of Ti, Zr, and W having an average particle diameter D50 of 0.1 to 0.8 μm. Further, Ti · Zr · W is preferably present in an island shape on the surface of the coating precursor. This can be easily confirmed by the coating precursor EPMA or the like.

  The precursor / coating precursor and lithium hydroxide monohydrate have a molar ratio of Li / (Ni + Co + Mn + additive if any) of 1.00 to 1.02 (1.004 to 1.02 when using a coating precursor). And dry-mix. At this time, lithium hydroxide monohydrate is preferably pulverized in advance by a jet mill so that D90 is smaller than 20 μm (if D90 is smaller than 20 μm at the acquisition stage, this step can be skipped). ). The dry mixing can be performed using a Henschel mixer, a Nauter mixer, or the like, but is preferably performed using a Henschel mixer. The number of revolutions and the like can be arbitrarily set so that they can be mixed well. For example, in the case of a 20 L Henschel mixer, it is preferable to mix at 1000 to 2000 rpm for 4 to 6 minutes. The mixed powder is fired in a firing furnace such as a muffle furnace, tunnel kiln, pusher furnace, roller hearth kiln. It is more preferable to use a roller hearth kiln that can be easily mass-produced. As an operation at the time of firing, the temperature is first raised to 400 to 500 ° C. in 2 to 3 hours from the oxygen atmosphere, and the temperature after the temperature rise is maintained for 3 to 10 hours while keeping the temperature. Then, the temperature is raised without cooling and kept at 700 to 800 ° C. for 1 to 10 hours. Then cool to room temperature. The produced fired product has a block shape.

  The fired block can be crushed with a roll crusher and a pulverizer in dry air to obtain a positive electrode active material powder. The dew point of dry air is preferably −30 ° C. or lower. More preferably, it is −40 ° C. or lower. Further, the obtained positive electrode active material powder may be electrolytically oxidized using the apparatus of FIG.

  The positive electrode active material A thus obtained is used alone or by blending the positive electrode active material A and the positive electrode active material B or the positive electrode active material C in dry air. To do. The blend can be easily produced using, for example, a Nauter mixer.

[Lithium ion battery]
A positive electrode for a lithium ion battery is produced using the positive electrode active material for a lithium ion battery according to each embodiment of the present invention, and further using the positive electrode for a lithium ion battery, a negative electrode, and an electrolyte containing an electrolyte or a solid electrolyte. Thus, a lithium ion battery can be manufactured.

Examples for better understanding of the present invention and its advantages are provided below, but the present invention is not limited to these examples. In addition, after taking out from the baking furnace in each case, it managed in dry air fundamentally except the case where it was necessary to adjust atmosphere at the time of evaluation. Further, TiO ₂ and ZrO ₂ having a median diameter of 0.3 to 0.4 μm and WO ₃ having a median diameter of 0.6 to 0.7 μm were used.

(Example 1)
Prepare transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate: cobalt sulfate: manganese sulfate is 85: 12: 3, and put them in one reaction tank. A precursor powder of Ni _0.85 Co _0.12 Mn _0.03 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing with water and drying.

This Ni _0.85 Co _0.12 Mn _0.03 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are put in one bag so that Li / (Ni + Co + Mn) is 1.01 in an air atmosphere with a humidity of 60%. The sample was weighed and the bag was inflated so that the opening was grasped by hand so that the powder did not leak. The hand that was not grasped was placed on the bottom of the bag, and the bag was shaken with both hands to roughly mix. All of the coarsely mixed powder (crude mixed powder) was put into a Henschel mixer from the bag, mixed at 1500 rpm for 5 minutes, and the mixed powder (mixed powder) was filled in an alumina slag. Fill the firing furnace with oxygen, put the alumina sagger in the firing furnace to an oxygen atmosphere of 0.1 MPa, hold at 490 ° C. (indicated as “pre-baking temperature” in the table) for 8 hours, and then raise the temperature. And kept at 700 ° C. (indicated as “calcination temperature” in the table) for 4 hours. This was cooled to room temperature at 5 ° C./min. After cooling, the alumina mortar was taken out from the firing furnace into dry air and crushed with a roll crusher and an ACM pulverizer to obtain a positive electrode active material of Example 1.

(Example 2)
Prepare transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate: cobalt sulfate: manganese sulfate is 85: 12: 3, and put them in one reaction tank. A precursor powder of Ni _0.85 Co _0.12 Mn _0.03 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing with water and drying. In the same manner as in Example 1, this was mixed with lithium hydroxide, baked, and pulverized to obtain a positive electrode active material of Example 2.

(Example 3)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 90: 7: 3 in separate tanks. A precursor powder of Ni _0.9 Co _0.07 Mn _0.03 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing with water and drying. Except that this Ni _0.9 Co _0.07 Mn _0.03 (OH) ₂ and LiOH · H ₂ O having a D90 of 20 μm or less were weighed in one bag and the firing temperature was 740 ° C., the same as in Example 2. The positive electrode active material of Example 3 was obtained.

(Example 4)
Prepare transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 89.5: 7.1: 3, and put them in one reaction tank. A precursor powder of Ni _0.895 Co _0.071 Mn _0.03 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

Ni _0.895 Co _0.071 Mn _0.03 (OH) ₂ and ZrO ₂ are mixed so that Ni: Co: Mn: Zr = 0.895: 0.071: 0.03: 0.0036 and the solid content is 10 wt% in total. Ni _0.895 Co _0.071 Mn _0.03 Zr _0.0036 (OH) _{2 in which} Zr is coated with Ni _0.895 Co _0.071 Mn _0.03 (OH) ₂ in an island shape. Got.

This Ni _0.895 Co _0.071 Mn _0.03 Zr _0.0036 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are _combined in one atmosphere so that Li / (Ni + Co + Mn) is 1.018 in an air atmosphere with a humidity of 60%. A positive electrode active material of Example 4 was obtained in the same manner as in Example 1 except that it was weighed in a bag and the firing temperature was 720 ° C.

(Example 5)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 89.3: 7.2: 3.1 in separate tanks. The precursor powder of Ni _0.893 Co _0.072 Mn _0.031 (OH) ₂ having the true density and tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

The Ni _0.893 Co _0.072 Mn _0.031 (OH) ₂ , ZrO _2, and TiO ₂ are mixed so that Ni: Co: Mn: Zr: Ti = 0.893: 0.072: 0.031: 0.0028: 0.0013 and the solid content is as a whole. dispersed in pure water to a 10 wt% concentration, subjected to spray drying in Fujisaki electric Ltd. micro mist dryer, Ni and Zr and Ti is coated on the islands to _{Ni 0.893 Co 0.072 Mn 0.031 (OH} ) 2 0.893 Co _0.072 Mn _0.031 Zr _0.0028 Ti _0.0013 (OH) ₂ was obtained.

This Ni _0.893 Co _0.072 Mn _0.031 Zr _0.0028 Ti _0.0013 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are set so that Li / (Ni + Co + Mn) is 1.000 in an air atmosphere with a humidity of 60%. A positive electrode active material of Example 5 was obtained in the same manner as Example 2 except that it was weighed into one bag.

(Example 6)
Prepare a separate tank of transition metal aqueous solution, caustic, and aqueous solution prepared so that nickel sulfate, cobalt sulfate, and manganese sulfate have a molar ratio of 88.1: 10: 1.9, and guanidine sulfate aqueous solution as G solution. Ni _0.881 Co _0.10 Mn _0.019 (OH) ₂ precursor powder having the true density and the tap density shown in Table 1 is obtained by putting it into one reaction vessel, reacting by crystallization method, filtering, washing and drying. Obtained.

The Ni _0.881 Co _0.10 Mn _0.019 (OH) ₂ and WO ₃ are mixed so that Ni: Co: Mn: W = 0.881: 0.10: 0.019: 0.001 and the total solid content is 10 wt%. Ni _0.881 Co _0.10 Mn _0.019 W _0.001 (OH) ₂ coated with Ni _0.881 Co _0.10 Mn _0.019 (OH) ₂ in an island shape after being spray-dried with a micro mist dryer manufactured by Fujisaki Electric. Got.

This Ni _0.881 Co _0.10 Mn _0.019 W _0.001 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are _combined in one atmosphere so that Li / (Ni + Co + Mn) is 1.005 in an air atmosphere with a humidity of 60%. A positive electrode active material of Example 6 was obtained in the same manner as in Example 1 except that it was weighed in a bag and the firing temperature was 720 ° C.

(Example 7)
Prepare transition metal aqueous solution, caustic and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 87.5: 7.5: 5, and put them in one reaction tank. The precursor powder of Ni _0.875 Co _0.075 Mn _0.05 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

This Ni _0.875 Co _0.075 Mn _0.05 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are put in one bag so that Li / (Ni + Co + Mn) is 1.020 in an air atmosphere with a humidity of 60%. The sample was weighed and the bag was inflated so that the opening was grasped by hand so that the powder did not leak. The hand that was not grasped was placed on the bottom of the bag, and the bag was shaken with both hands to roughly mix. All of the coarsely mixed powder (crude mixed powder) was put into a Henschel mixer from the bag and mixed at 1500 rpm for 5 minutes, and the mixed powder (mixed powder) was filled in an alumina sagger. The firing furnace was filled with oxygen, and the alumina sagger was placed in a firing furnace to make an oxygen atmosphere of 0.1 MPa, held at 500 ° C. for 8 hours, then heated to 700 ° C. for 4 hours. This was cooled to room temperature at 5 ° C./min. After cooling, the alumina bowl is taken out from the firing furnace into dry air, crushed with a roll crusher and an ACM pulverizer, and subjected to electrolytic oxidation at 10 V in supercritical oxygen for 30 seconds using the apparatus shown in FIG. A positive electrode active material was obtained.

(Example 8)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 87.0: 12: 1 in separate tanks. A precursor powder of Ni _0.870 Co _0.12 Mn _0.01 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing with water and drying.

This Ni _0.870 Co _0.12 Mn _0.01 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are put in one bag so that Li / (Ni + Co + Mn) is 1.000 in an air atmosphere with a humidity of 60%. A positive electrode active material of Example 8 was obtained in the same manner as in Example 1 except that weighing was performed, the pre-baking temperature was 480 ° C., and the baking temperature was 740 ° C.

(Production Example 1)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 80.0: 15: 5 in separate tanks. The precursor powder of Ni _0.800 Co _0.15 Mn _0.05 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing with water and drying.

This Ni _0.800 Co _0.15 Mn _0.05 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are put in one bag so that Li / (Ni + Co + Mn) is 1.020 in an air atmosphere with a humidity of 60%. A positive electrode active material of Production Example 1 was obtained in the same manner as in Example 1 except that weighing was performed and the firing temperature was set to 740 ° C.

(Production Example 2)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 84.0: 15: 1, and put them in one reaction tank. A precursor powder of Ni _0.840 Co _0.15 Mn _0.01 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an _analysis method, filtering, washing with water and drying.

This Ni _0.840 Co _0.15 Mn _0.01 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are put in one bag so that Li / (Ni + Co + Mn) is 1.000 in an air atmosphere with a humidity of 60%. A positive electrode active material of Production Example 2 was obtained in the same manner as in Example 1 except that weighing was performed and the firing temperature was 720 ° C.

(Production Example 3)
Prepare a separate tank of transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 83.9: 11.1: 5, and guanidine sulfate aqueous solution as G solution. Ni _0.839 Co _0.111 Mn _0.05 (OH) ₂ precursor powder having the true density and tap density shown in Table 1 is obtained by putting it into one reaction vessel, reacting by crystallization, filtering, washing and drying. Obtained.

_{Except that} this Ni _0.839 Co _0.111 Mn _0.05 (OH) ₂ and LiOH · H ₂ O having a D90 of 20 μm or less were weighed in one bag and the firing temperature was 720 ° C., the same as in Example 1. A positive electrode active material of Production Example 3 was obtained.

(Production Example 4)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 82.8: 14.7: 2.5 in separate tanks. A precursor powder of Ni _0.828 Co _0.147 Mn _0.025 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an _analysis method, filtering, washing with water and drying.

Ni _0.828 Co _0.147 Mn _0.025 (OH) ₂ and WO ₃ are _mixed so that Ni: Co: Mn: W = 0.828: 0.147: 0.025: 0.002 and the total solid content is 10 wt%. Ni _0.828 Co _0.147 Mn _0.025 W _0.002 (OH) ₂ coated with Ni _0.828 Co _0.147 Mn _0.025 (OH) ₂ in an island shape after spray drying with a micro mist dryer manufactured by Fujisaki Electric. Got.

This Ni _0.828 Co _0.147 Mn _0.025 W _0.002 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are _combined into one so that Li / (Ni + Co + Mn) is 1.010 in an air atmosphere with a humidity of 60%. A positive electrode active material of Production Example 4 was obtained in the same manner as in Example 7, except that it was weighed in a bag and the firing temperature was 730 ° C.

(Production Example 5)
Prepare transition metal aqueous solution, caustic and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 84.0: 14.0: 2, and put them in separate reactors. A precursor powder of Ni _0.840 Co _0.140 Mn _0.02 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an _analysis method, filtering, washing and drying.

The Ni _0.840 Co _0.140 Mn _0.02 (OH) ₂ , TiO ₂ and WO ₃ are combined so that Ni: Co: Mn: Ti: W = 0.840: 0.140: 0.02: 0.003: 0.006 and the solid content is as a whole. dispersed in pure water to a 10 wt% concentration, subjected to spray drying in Fujisaki electric Ltd. micro mist dryer, Ni which Ti and W were coated in an island shape on the _{Ni 0.840 Co 0.140 Mn 0.02 (OH} ) 2 0.840 Co _0.140 Mn _0.02 Ti _0.003 W _0.006 (OH) ₂ was obtained.

This Ni _0.840 Co _0.140 Mn _0.02 Ti _0.003 W _0.006 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are set so that Li / (Ni + Co + Mn) is 1.020 in an air atmosphere with a humidity of 60%. A positive electrode active material of Production Example 5 was obtained in the same manner as Example 1 except that it was weighed into one bag and the pre-baking temperature was 480 ° C.

(Production Example 6)
Prepare transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 81.8: 15: 3.2. A precursor powder of Ni _0.818 Co _0.15 Mn _0.032 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

_{Except that} this Ni _0.818 Co _0.15 Mn _0.032 (OH) ₂ and LiOH · H ₂ O having a D90 of 20 μm or less were weighed in one bag and the firing temperature was 740 ° C., the same as in Example 1. A positive electrode active material of Production Example 6 was obtained.

(Production Example 7)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 80.4: 14.9: 3.3 in separate tanks. The precursor powder of Ni _0.804 Co _0.149 Mn _0.033 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an _analysis method, filtering, washing with water and drying.

Ni _0.804 Co _0.149 Mn _0.033 (OH) ₂ and ZrO ₂ are mixed so that Ni: Co: Mn: Zr = 0.804: 0.149: 0.033: 0.014 and the total solid content is 10 wt%. Ni _0.804 Co _0.149 Mn _0.033 Zr _0.014 (OH) _{2 in which} Zr is coated with Ni _0.804 Co _0.149 Mn _0.033 (OH) ₂ in an island shape. Got.

This Ni _0.804 Co _0.149 Mn _0.033 Zr _0.014 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are _combined in one atmosphere so that Li / (Ni + Co + Mn) is 1.008 in an atmospheric atmosphere with a humidity of 60%. A positive electrode active material of Production Example 7 was obtained in the same manner as in Example 1 except that it was weighed in a bag and the firing temperature was 740 ° C.

(Production Example 8)
Prepare the transition metal aqueous solution, caustic and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 80.6: 14.8: 3.1 in separate tanks. A precursor powder of Ni _0.806 Co _0.148 Mn _0.031 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

The Ni _0.806 Co _0.148 Mn _0.031 (OH) ₂ , ZrO ₂ and TiO ₂ are _mixed so that Ni: Co: Mn: Zr: Ti = 0.006: 0.148: 0.031: 0.01: 0.005 and the total solid content is dispersed in pure water to a 10 wt% concentration, subjected to spray drying in Fujisaki electric Ltd. micro mist dryer, Ni and Zr and Ti is coated on the islands to _{Ni 0.806 Co 0.148 Mn 0.031 (OH} ) 2 0.806 Co _0.148 Mn _0.031 Zr _0.01 Ti _0.005 (OH) ₂ was obtained.

This Ni _0.806 Co _0.148 Mn _0.031 Zr _0.01 Ti _0.005 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are set so that Li / (Ni + Co + Mn) is 1.005 in an air atmosphere with a humidity of 60%. A positive electrode active material of Production Example 8 was obtained in the same manner as Example 1 except that it was weighed in one bag and the firing temperature was 720 ° C.

(Comparative Example 1)
Prepare transition metal aqueous solution prepared so that nickel sulfate, cobalt sulfate, and manganese sulfate have a molar ratio of 85: 12: 3, caustic, and aqueous solution in separate tanks. A precursor powder of Ni _0.850 Co _0.12 Mn _0.03 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an _analysis method, filtering, washing with water and drying. This was mixed with lithium hydroxide, fired and crushed in the same manner as in Example 1 to obtain a positive electrode active material of Comparative Example 1.

(Comparative Example 2)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 90: 7: 3 in separate tanks. A precursor powder of Ni _0.9 Co _0.07 Mn _0.03 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing with water and drying.

This Ni _0.9 Co _0.07 Mn _0.03 (OH) ₂ and LiOH · H ₂ O having a D90 of 20 μm or less were weighed in one bag, the pre-baking temperature was set to 530 ° C., and the baking temperature was set to 780 ° C. A positive electrode active material of Comparative Example 2 was obtained in the same manner as Example 2 except that.

(Comparative Example 3)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 89.4: 7.2: 3 in separate tanks. A precursor powder of Ni _0.894 Co _0.072 Mn _0.03 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an _analysis method, filtering, washing and drying.

Ni _0.894 Co _0.072 Mn _0.03 (OH) ₂ and ZrO ₂ are mixed so that Ni: Co: Mn: Zr = 0.894: 0.072: 0.03: 0.0037 and the total solid content is 10 wt%. Ni _0.894 Co _0.072 Mn _0.03 Zr _0.0037 (OH) _{2 in which} Zr is coated with Ni _0.894 Co _0.072 Mn _0.03 (OH) ₂ in an island shape by spraying with a micro mist dryer manufactured by Fujisaki Electric. Got.

This Ni _0.894 Co _0.072 Mn _0.03 Zr _0.0037 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are _combined in one atmosphere so that Li / (Ni + Co + Mn) is 1.042 in an atmospheric atmosphere with a humidity of 60%. A positive electrode active material of Comparative Example 3 was obtained in the same manner as in Example 1 except that it was weighed in a bag, the pre-baking temperature was 470 ° C., and the baking temperature was 740 ° C.

(Comparative Example 4)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 89.3: 7.2: 3.1 in separate tanks. The precursor powder of Ni _0.893 Co _0.072 Mn _0.031 (OH) ₂ having the true density and tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

The Ni _0.893 Co _0.072 Mn _0.031 (OH) ₂ , ZrO _2, and TiO ₂ are mixed so that Ni: Co: Mn: Zr: Ti = 0.893: 0.072: 0.031: 0.0028: 0.0013 and the solid content is as a whole. dispersed in pure water to a 10 wt% concentration, subjected to spray drying in Fujisaki electric Ltd. micro mist dryer, Ni and Zr and Ti is coated on the islands to _{Ni 0.893 Co 0.072 Mn 0.031 (OH} ) 2 0.893 Co _0.072 Mn _0.031 Zr _0.0028 Ti _0.0013 (OH) ₂ was obtained.

This Ni _0.893 Co _0.072 Mn _0.031 Zr _0.0028 Ti _0.0013 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are set so that Li / (Ni + Co + Mn) is 1.000 in an air atmosphere with a humidity of 60%. A positive electrode active material of Comparative Example 4 was obtained in the same manner as Example 2 except that it was weighed into one bag and the firing temperature was 760 ° C.

(Comparative Example 5)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 80.6: 9.8: 9.6 in separate tanks. A precursor powder of Ni _0.806 Co _0.098 Mn _0.096 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

This Ni _0.806 Co _0.098 Mn _0.096 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are put in one bag so that Li / (Ni + Co + Mn) is 1.020 in an air atmosphere with a humidity of 60%. A positive electrode active material of Comparative Example 5 was obtained in the same manner as Example 1 except that the measurement was performed and the firing temperature was 840 ° C.

(Comparative Example 6)
Prepare transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 81.8: 15: 3.2. A precursor powder of Ni _0.818 Co _0.15 Mn _0.032 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

_{Except that} this Ni _0.818 Co _0.15 Mn _0.032 (OH) ₂ and LiOH · H ₂ O having a D90 of 20 μm or less were weighed in one bag and the firing temperature was 680 ° C., the same as in Example 1. A positive electrode active material of Comparative Example 6 was obtained.

(Comparative Example 7)
Prepare the transition metal aqueous solution, caustic, and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 80.4: 14.9: 3.3 in separate tanks. The precursor powder of Ni _0.804 Co _0.149 Mn _0.033 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an _analysis method, filtering, washing with water and drying.

Ni _0.804 Co _0.149 Mn _0.033 (OH) ₂ and ZrO ₂ are mixed so that Ni: Co: Mn: Zr = 0.804: 0.149: 0.033: 0.014 and the total solid content is 10 wt%. Ni _0.804 Co _0.149 Mn _0.033 Zr _0.014 (OH) _{2 in which} Zr is coated with Ni _0.804 Co _0.149 Mn _0.033 (OH) ₂ in an island shape. Got.

This Ni _0.804 Co _0.149 Mn _0.033 Zr _0.014 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are _{combined in a single} atmosphere so that Li / (Ni + Co + Mn) is 1.008 in an air atmosphere with a humidity of 60%. A positive electrode active material of Comparative Example 7 was obtained in the same manner as in Example 1 except that it was weighed in a bag and the firing temperature was 680 ° C.

(Comparative Example 8)
Prepare the transition metal aqueous solution, caustic and aqueous solution prepared so that the molar ratio of nickel sulfate, cobalt sulfate, and manganese sulfate is 80.6: 14.8: 3.1 in separate tanks. A precursor powder of Ni _0.806 Co _0.148 Mn _0.031 (OH) ₂ having the true density and the tap density shown in Table 1 was obtained by reacting by an analysis method, filtering, washing and drying.

The Ni _0.806 Co _0.148 Mn _0.031 (OH) ₂ , ZrO ₂ and TiO ₂ are _mixed so that Ni: Co: Mn: Zr: Ti = 0.006: 0.148: 0.031: 0.01: 0.005 and the total solid content is dispersed in pure water to a 10 wt% concentration, subjected to spray drying in Fujisaki electric Ltd. micro mist dryer, Ni and Zr and Ti is coated on the islands to _{Ni 0.806 Co 0.148 Mn 0.031 (OH} ) 2 0.806 Co _0.148 Mn _0.031 Zr _0.01 Ti _0.005 (OH) ₂ was obtained.

This Ni _0.806 Co _0.148 Mn _0.031 Zr _0.01 Ti _0.005 (OH) ₂ and LiOH.H ₂ O having a D90 of 20 μm or less are set so that Li / (Ni + Co + Mn) is 1.005 in an air atmosphere with a humidity of 60%. A positive electrode active material of Comparative Example 8 was obtained in the same manner as Example 1 except that it was weighed in one bag and the firing temperature was 820 ° C.

(Example 9)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 6 were mixed at a mass ratio of 80:20 in dry air to obtain a positive electrode active material of Example 9.

(Example 10)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 6 were mixed at a mass ratio of 70:30 in dry air to obtain a positive electrode active material of Example 10.

(Example 11)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 6 were mixed at a mass ratio of 60:40 in dry air to obtain a positive electrode active material of Example 11.

(Example 12)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 6 were mixed at a mass ratio of 50:50 in dry air to obtain a positive electrode active material of Example 12.

(Example 13)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 8 were mixed at a mass ratio of 70:30 in dry air to obtain a positive electrode active material of Example 13.

(Example 14)
The positive electrode active material of Example 5 and the positive electrode active material of Production Example 8 were mixed at a mass ratio of 80:20 in dry air to obtain a positive electrode active material of Example 14.

(Example 15)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 1 were mixed at a mass ratio of 90:10 in dry air to obtain a positive electrode active material of Example 15.

(Example 16)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 2 were mixed at a mass ratio of 75:25 in dry air to obtain a positive electrode active material of Example 16.

(Example 17)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 3 were mixed at a mass ratio of 60:40 in dry air to obtain a positive electrode active material of Example 17.

(Example 18)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 4 were mixed at a mass ratio of 50:50 in dry air to obtain a positive electrode active material of Example 18.

(Example 19)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 5 were mixed at a mass ratio of 40:60 in dry air to obtain a positive electrode active material of Example 19.

(Example 20)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 7 were mixed at a mass ratio of 25:75 in dry air to obtain a positive electrode active material of Example 20.

(Example 21)
The positive electrode active material of Example 5 and the positive electrode active material of Production Example 6 were mixed at a mass ratio of 10:90 in dry air to obtain a positive electrode active material of Example 21.

(Example 22)
The positive electrode active material of Example 3 and the positive electrode active material of Production Example 6 were mixed at a mass ratio of 95: 5 in dry air to obtain a positive electrode active material of Example 22.

(Example 23)
The positive electrode active material of Example 5 and the positive electrode active material of Production Example 8 were mixed at a mass ratio of 5:95 in dry air to obtain a positive electrode active material of Example 23.

(Comparative Example 9)
The positive electrode active material of Comparative Example 4 and the positive electrode active material of Comparative Example 6 were mixed in dry air at a mass ratio of 95: 5 to obtain a positive electrode active material of Comparative Example 9.

(Comparative Example 10)
The positive electrode active material of Example 3 and the positive electrode active material of Comparative Example 5 were mixed in dry air at a mass ratio of 70:30 to obtain a positive electrode active material of Comparative Example 10.

(Comparative Example 11)
The positive electrode active material of Comparative Example 2 and the positive electrode active material of Production Example 8 were mixed in dry air at a mass ratio of 70:30 to obtain a positive electrode active material of Comparative Example 11.

(Evaluation)
Each evaluation was carried out under the following conditions using the samples of Examples, Production Examples and Comparative Examples thus prepared.
-Evaluation of SEM and EPMA-
JSM-7000F type manufactured by JEOL Ltd. was used for SEM observation and EPMA measurement. As an example of the SEM image, FIG. The primary particle aspect ratio is determined by reading the longest part of each primary particle from the SEM image as the major axis diameter, and out of the lines perpendicular to the straight line connecting both ends of the longest part, the longest part is the minor axis diameter. And (major axis diameter) / (minor axis diameter) of each primary particle was calculated from the values of the major axis diameter and minor axis diameter, and the average value was taken as the primary particle aspect ratio of each example. At this time, the number of measurements n for obtaining an average value was 10 or more. In addition, the presence or absence of island coating was determined by a conventional method from the mapping image of EPMA Ti, Zr, and W.

-10% volume diameter D10: Evaluation of γ and median diameter-
The 10% volume diameter D10: γ and the median diameter were defined as 10% volume diameter and median diameter in the particle size distribution measured by a laser diffraction method using Microtrack MT3000EX II manufactured by Nikkiso Co., Ltd.

-Evaluation of specific surface area-
The specific surface area was measured by degassing the positive electrode active material at 150 ° C. for 2 hours, and then using BET method (1) using a mixed gas of 70 atm% -N ₂ 30% as adsorption gas with Monosorb manufactured by Cantachrome. The point method was used for measurement.

-Evaluation of true density-
The true density was measured with Accupic II 1340 manufactured by Shimadzu Corporation.

-Evaluation of tap density of precursor and coating precursor-
The tap density of the precursor and the coating precursor was measured using a tap denser manufactured by Seishin Enterprise Co., Ltd., 10 g of the powder sample was placed in a graduated cylinder, and the tap density was measured from the volume after tapping 30 times.

-Evaluation of tap density β of positive electrode active material-
The tap density β of the positive electrode active material was measured using a tap denser manufactured by Seishin Enterprise Co., Ltd., and 10 g of the powder sample was placed in a graduated cylinder and the tap density was measured from the volume after tapping 1500 times.

-Evaluation of battery characteristics (Liquid lithium ion battery)-
In dry air, the obtained positive electrode active material, conductive material (Denka Black), and binder (PVdF) are weighed in a ratio of 90: 5: 5, and the binder is dissolved in an organic solvent (N-methylpyrrolidone). Then, a positive electrode active material and a conductive material were mixed to form a slurry, applied onto an Al foil, dried, and pressed to obtain a positive electrode. Subsequently, a 2032-type coin cell for evaluation with a Li metal foil as a counter electrode was produced in a glove box in an argon atmosphere, and LiPF ₆ was used as an electrolytic solution, and a volume ratio of EC and DMC in a 1: 1 mixed solvent of 1M was used. The initial capacity obtained at a discharge rate of 0.05 C (25 ° C., upper limit voltage for charging: 4.3 V, lower limit voltage for discharging: 3.0 V) was measured using the sample dissolved at the concentration. In addition, a 2032 type coin cell manufactured under the same conditions as above and with the same electrolyte solution was charged at a discharge rate of 1 C, a charge upper limit voltage of 4.3 V, and a discharge lower limit voltage of 3.0 V in a thermostatic chamber set at 55 ° C. Discharge, and perform the same charge and discharge up to 20 cycles with this as the first cycle, calculate the discharge capacity at 20th cycle as a percentage when the discharge capacity at 1st cycle is 100%, capacity maintenance rate after 20 cycles (%).

-Output evaluation (Liquid lithium ion battery)-
・ Production method of negative electrode Raw material coke obtained from desulfurized oil and light oil was mixed with graphite material obtained by heating in a nitrogen gas stream and polyvinylidene fluoride as a binder at a mass ratio of 92: 8. After adding -methyl-2-pyrrolidinone and kneading, it was made into a paste and applied to one side of a copper foil, followed by drying and rolling operations to produce a negative electrode. The coating amount per unit area of the negative electrode was set to 10 mg / cm ² as the mass of the graphite material.

-Manufacturing method of a positive electrode The positive electrode was produced in dry air. First, the positive electrode active material produced in each example, each production example, and each comparative example, and polyvinylidene fluoride and acetylene black as a binder were mixed at a mass ratio of 89: 6: 5, and N-methyl- After 2-pyrrolidinone was added and kneaded, it was made into a paste and applied to one side of an aluminum foil, followed by drying and rolling operations to produce positive electrodes for each example, each production example, and each comparative example. The coating amount per unit area of each positive electrode was set to 20 mg / cm ² as the mass of the positive electrode active material.

Battery assembly Each positive electrode, negative electrode, separator, electrolyte, and battery shell component described above were introduced into a glove box filled with argon gas, and a battery was assembled by a conventional method. The electrolyte used was a solution in which lithium hexafluorophosphate (LiPF ₆ ) was dissolved at a concentration of 1 mol / L in a solvent in which ethylene carbonate and ethyl methyl carbonate were mixed at a volume ratio of 3: 7. .

-Battery test The obtained battery was installed in a constant temperature room of 55 degreeC, and the following charge / discharge test was done. First, it was charged with a constant current until the battery voltage reached 4.2 V at a current of 4 mA. After a pause (1) for 10 minutes, the battery was discharged at a constant current until the battery voltage reached 3.0 V with the same current. These charging, resting, and discharging were defined as one charging / discharging cycle (1), and the charging / discharging cycle (1) was repeated three times. After that, constant current / constant voltage charging was performed with a charging current of 30 mA, a charging voltage of 4.2 V, and a charging time of 3 hours. After 10 minutes of rest (2), the battery voltage was 3.0 with the same current (30 mA). The battery was discharged at a constant current until V was reached. These charging, resting, and discharging are defined as one charging / discharging cycle (2), and the charging / discharging cycle (2) is repeated three times. Next, the charging current is 30 mA, the charging voltage is 4.2 V, and the charging time is 3 hours. The constant current / constant voltage charging was performed, and after 10 minutes of rest (3), the battery was discharged at a constant current at 75 mA until the battery voltage reached 3.0V. When a series of processes from the start of the 10-minute pause (3) to the completion of the constant-current discharge is defined as a constant-current discharge process A, the open-circuit voltage (OCV) after the 10-minute pause of the constant-current discharge process A and the constant current From the closed circuit voltage (CCV) 3 seconds after the start of the constant current discharge of the discharge process A and the discharge current (I) 3 seconds after the start of the discharge of the constant current discharge process A, the output (unit W) of the laminated exterior battery is Calculated by the formula.
Output (unit W) = (OCV−CCV) × I
These conditions and results are shown in Tables 1-3.

1 Electrolytic oxidation (anodic oxidation) equipment
2 Supercritical oxygen (pressure: 5.1MPa, temperature: 160K)
3 Cathode
4 Anode drum (rotates at 5 rpm with outer shell)
5 Active material during electrolytic oxidation
6 Separator

Claims (12)

Composition formula: Li _a Ni _b Co _c Mn _d O ₂
(In the above formula, 1.00 ≦ a ≦ 1.02, 0.85 ≦ b ≦ 0.9, 0.07 ≦ c ≦ 0.12, 0.01 ≦ d ≦ 0.05, b + c + d = 1)
Represented by
Α × β × γ is 3-6 when the specific surface area is α (m ² / g), 1500 times tap density is β (g / cc), and 10% volume diameter (D10) is γ (μm). A positive electrode active material for a lithium ion battery, wherein the primary particles have an aspect ratio of 1 to 4. A positive electrode active material having a core particle and a coating provided on the surface of the core particle,
Composition _{formula: Li a Ni b Co c Mn} d Mz e O 2
(In the above formula, 1.004 ≦ a ≦ 1.02, 0.85 ≦ b ≦ 0.9, 0.07 ≦ c ≦ 0.12, 0.01 ≦ d ≦ 0.05, 0 ≦ e ≦ 0.005, b + c + d = 1, Mz is W, Ti, Zr At least one selected from)
Represented by
Α × β × γ is 3-6 when the specific surface area is α (m ² / g), 1500 times tap density is β (g / cc), and 10% volume diameter (D10) is γ (μm). Yes, the primary particles have an aspect ratio of 1 to 4,
The said coating film is a positive electrode active material for lithium ion batteries which is comprised by the particle | grains containing the said Mz, and is formed in the island form.   3. The positive electrode active material for a lithium ion battery according to claim 1, wherein the median diameter is 3 to 15 μm. The positive electrode active material A according to any one of claims 1 to 3,
Composition formula: Li _a Ni _b Co _c Mn _d O ₂
(In the above formula, 1.00 ≦ a ≦ 1.02, 0.80 ≦ b <0.85, 0.10 <c ≦ 0.15, 0.01 ≦ d ≦ 0.05, b + c + d = 1)
Represented by
Α × β × γ is 3-6 when the specific surface area is α (m ² / g), 1500 times tap density is β (g / cc), and 10% volume diameter (D10) is γ (μm). A positive electrode active material B having an aspect ratio of primary particles of 1 to 4;
A positive electrode active material for lithium ion batteries obtained by mixing   5. The positive electrode active material for a lithium ion battery according to claim 4, wherein the positive electrode active material B has a median diameter of 3 to 8 μm.   6. The positive electrode active material for a lithium ion battery according to claim 4, wherein the positive electrode active material A and the positive electrode active material B are mixed at a mass ratio of 10:90 to 90:10. The positive electrode active material A according to any one of claims 1 to 3,
A positive electrode active material having a core particle and a coating provided on the surface of the core particle,
Composition _{formula: Li a Ni b Co c Mn} d Mz e O 2
(In the above formula, 1.004 ≦ a ≦ 1.02, 0.80 ≦ b <0.85, 0.10 <c ≦ 0.15, 0.01 ≦ d ≦ 0.05, 0 ≦ e ≦ 0.015, b + c + d = 1, Mz is W, Ti, Zr At least one selected from)
Represented by
Α × β × γ is 3-6 when the specific surface area is α (m ² / g), 1500 times tap density is β (g / cc), and 10% volume diameter (D10) is γ (μm). Yes, the primary particles have an aspect ratio of 1 to 4,
The coating film is composed of particles containing the Mz and is formed into an island-like positive electrode active material C;
A positive electrode active material for lithium ion batteries obtained by mixing   8. The positive electrode active material for a lithium ion battery according to claim 7, wherein the median diameter of the positive electrode active material C is 3 to 8 μm.   9. The positive electrode active material for a lithium ion battery according to claim 7, wherein the positive electrode active material A and the positive electrode active material C are mixed at a mass ratio of 10:90 to 90:10.   A lithium ion battery comprising a positive electrode comprising the positive electrode active material for a lithium ion battery according to any one of claims 1 to 9, a negative electrode, and an electrolyte containing an electrolytic solution or a solid electrolyte. A method for producing the positive electrode active material for a lithium ion battery according to claim 1 or 3, or the positive electrode active material B in the positive electrode active material for a lithium ion battery according to claim 4 or 6,
A step of dry-mixing nickel cobalt manganese hydroxide powder having a true density of 3.7 to 3.8 g / cc and a tap density of 1.3 to 1.9 g / cc with lithium hydroxide; and
The powder obtained by dry mixing is fired at 400 to 500 ° C. in an oxygen atmosphere, heated without cooling, and further fired at 700 to 800 ° C. Production method. A method for producing the positive electrode active material for a lithium ion battery according to claim 2 or 3, or the positive electrode active material C in the positive electrode active material for a lithium ion battery according to claim 7 or 8,
A step of dispersing nickel cobalt manganese hydroxide particles having a true density of 3.7 to 3.8 g / cc and a tap density of 1.3 to 1.9 g / cc in water to form a slurry;
Adding at least one particle having a median diameter of 0.1 to 0.8 μm selected from the group consisting of TiO ₂ , ZrO ₂ , and WO ₃ to the slurry and spray-drying;
A step of dry-mixing the spray-dried product produced by the spray-drying with lithium hydroxide; and
The powder obtained by dry mixing is fired at 400 to 500 ° C. in an oxygen atmosphere, heated without cooling, and further fired at 700 to 800 ° C. Production method.