JP6619832B2 - Oxide positive electrode active material for lithium ion battery, method for producing precursor of oxide positive electrode active material for lithium ion battery, method for producing oxide positive electrode active material for lithium ion battery, positive electrode for lithium ion battery and lithium ion battery - Google Patents

Description

  The present invention relates to an oxide-based positive electrode active material for a lithium ion battery, a method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery, a method for producing an oxide-based positive electrode active material for a lithium ion battery, and a lithium ion battery The present invention relates to a positive electrode and a lithium ion battery.

Lithium-containing transition metal oxides are generally used as the positive electrode active material for lithium ion secondary batteries. Specifically, the layered compound lithium cobaltate (LiCoO ₂ ), the layered compound lithium nickelate (LiNiO ₂ ), the spinel compound lithium manganate (LiMn ₂ O ₄ ), etc., improved characteristics (higher capacity, cycle characteristics, Combining them (blending, granulation, etc.) to improve storage characteristics, internal resistance reduction, rate characteristics) and safety is being promoted. Lithium ion secondary batteries for large-scale applications such as in-vehicle use and load leveling are required to have different characteristics from those of conventional mobile phones and personal computers.

Therefore, Li ₂ MnO ₃ —Li (Ni, Co, Mn) O called Li-rich, Mn-rich, or solid solution positive electrode active material or the like is particularly used in applications requiring a flat discharge curve over a long period of time, such as for load leveling. A positive electrode active material having a composition formula represented by ₂ has been studied. It is known that a positive electrode active material having a discharge capacity of 200 mAh / g or more can be produced by variously changing the ratio of Li ₂ MnO ₃ and Li (Ni, Co, Mn) O ₂ ( For example, Patent Document 1).

JP 2013-161621 A

This solid solution positive electrode active material promotes Li ion conduction in the positive electrode active material by combining Li ₂ MnO ₃ with a layered compound that is thought to have been saturated in Li ion conduction in the conventional positive electrode active material. Thus, it is intended to realize a flat discharge curve and a high capacity at a level not found in conventional layered compounds. However, this Li ₂ MnO ₃ complexation inevitably increases the molar ratio of Li to the transition metal (hereinafter referred to as Li / Me ratio), so that it is necessary to charge a large amount of lithium source such as lithium carbonate during firing. For example, in Patent Document 1, the Li / Me ratio is as high as about 1.2. In such a case, it is sufficient that all Li is successfully converted into a lithium composite oxide at the time of firing. However, in reality, this is not the case. In particular, a material such as Li-rich is always in the form of lithium carbonate or lithium hydroxide even after firing. Thus, a lithium source (hereinafter referred to as alkali) that was not taken into the lithium composite oxide remained.

In addition, since the electronic conductivity is inevitably lowered by the Li ₂ MnO ₃ composite, in Patent Document 1, carbonate is selected as the transition metal precursor. Thereby, it becomes a positive electrode material with small primary particles after firing, so that the interface with the electrolytic solution is increased, a smooth electrode reaction is realized, and a discharge capacity of 200 mAh / g can be secured. At this time, it is inevitable that the tap density is reduced, and therefore, energy density: (electrode density) × (discharge capacity) is reduced. For example, a material containing a relatively large amount of Ni in Li (Ni, Co, Mn) O ₂ can achieve 200 mAh / g. However, even if a transition metal precursor of hydroxide is used in a normal vehicle-mounted / power application, it is sufficient. Since electron conductivity can be ensured, as a result, energy density: (electrode density) × (discharge capacity) is improved. On the other hand, in Li-rich, as described above, since the tap density is low, energy density: (electrode density) × (discharge capacity) is also low, and in order to improve this, further improvement of discharge capacity is required. It was.

  As a means for this, it was expected that increasing the amount of Mn could increase the amount of Li / Me ratio and increase the discharge capacity, but the alkali increased accordingly, and from this point It has been said that there is an upper limit to the discharge capacity, or even if an attempt is made to increase the discharge capacity, there is a high possibility of gelation during electrode preparation.

  Patent Document 1 discloses a process in which ammonia water is dropped into a transition metal aqueous solution to adjust pH to 7 and then sodium carbonate is added in the production of the solid solution positive electrode active material. This method is simple and can easily produce fine primary particles after firing. For example, if a discharge capacity of 250 mAh / g is to be secured, the Li / Me ratio must be charged at about 1.5, Since alkali exceeded 1 mass% and it gelatinized at the time of electrode production, discharge capacity fell and it was difficult to obtain favorable discharge capacity.

  Then, this invention makes it a subject to provide the oxide type positive electrode active material which can make a low alkali amount and high energy density compatible, even if it is a composition with high Li ratio.

In one embodiment of the present invention, the metal composition is Li _a Ni _b Co _c Mn _1-bc
(In the formula, 1.40 ≦ a ≦ 1.48, 0.16 ≦ b ≦ 0.17, 0.16 ≦ c ≦ 0.17)
And an oxide-based positive electrode active material for a lithium ion battery having a residual alkali content of 0.7% by mass or less.

  In another embodiment, the oxide-based positive electrode active material for a lithium ion battery of the present invention has an average particle diameter D50 of 9.0 to 14.0 μm.

In yet another embodiment, the oxide-based positive electrode active material for a lithium ion battery of the present invention has a tap density of 1.4 g / cm ³ or more.

In yet another embodiment of the present invention, an aqueous solution containing an aqueous solution of nickel salt, cobalt salt, manganese salt, aqueous ammonia and carbonate is used as a reaction solution, and the pH in the reaction solution is 9.6-10. 5, including a step of performing a crystallization reaction while controlling the ammonium ion concentration to 2.5 g / L or less and the liquid temperature to 40 to 60 ° C.,
Composition formula _{(Ni x Co y Mn 1-} xy) CO 3
(Wherein, 0.16 ≦ x ≦ 0.17 and 0.16 ≦ y ≦ 0.17). A method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery. .

  In another embodiment of the method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery according to the present invention, the precursor has an average particle diameter D50 of 7.0 to 17.0 μm.

In yet another embodiment of the present invention, the precursor produced by the method of the present invention is obtained by combining the number of metal atoms (Me) made of Ni, Co and Mn with the number of lithium atoms (Me). Li / Me) is mixed to be 1.40 to 1.48 to form a lithium mixture;
Baking the lithium mixture at 750 to 950 ° C. in an air atmosphere;
It is a manufacturing method of the oxide type positive electrode active material for lithium ion batteries containing.

  In yet another embodiment, the present invention is a positive electrode for a lithium ion battery comprising the oxide-based positive electrode active material for a lithium ion battery of the present invention.

  In another embodiment, the present invention is a lithium ion battery provided with the positive electrode for a lithium ion battery of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a composition with a high Li ratio, the oxide type positive electrode active material which can make a low alkali amount and high energy density compatible can be provided.

(Configuration of oxide positive electrode active material for lithium ion battery)
An oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention has a metal composition of Li _a Ni _b Co _c Mn _1-bc
(In the formula, 1.40 ≦ a ≦ 1.48, 0.16 ≦ b ≦ 0.17, 0.16 ≦ c ≦ 0.17)
The residual alkali amount contained is 0.7 mass% or less.

The oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention has a high molar ratio of 1.40 or more and 1.48 or less with respect to the total of other metals (Ni, Co, Mn) of Li in the composition formula. However, it is possible to achieve both a low alkali amount and a high energy density by controlling the residual alkali content to be 0.7% by mass or less. Here, “energy density (mAh / cm ³ )” means (electrode density) × (discharge capacity), and when the energy density is high, other than the effect of increasing the charged amount of a normal battery. In addition, there is an effect that even a small storage battery can store a large amount of electric power. In addition, the discharge capacity said here is the discharge capacity which the lithium ion battery provided with the said positive electrode active material in the positive electrode has. The energy density is preferably at 540mAh / cm ³ or more, more preferably 580mAh / cm ³ or more, still more preferably at 600 mAh / cm ³ or more.

  In the oxide-based positive electrode active material for a lithium ion battery according to the embodiment of the present invention, if the composition of Li is less than 1.40, the amount of lithium is insufficient and it is difficult to maintain a stable crystal structure. There is a possibility that the discharge capacity of a lithium ion battery manufactured using the positive electrode active material may be lowered.

  The average particle diameter D50 of the oxide-based positive electrode active material for a lithium ion battery according to the embodiment of the present invention is preferably 9.0 to 14.0 μm. According to such a configuration, there is an advantage that the powder density is high, and breakage of the metal foil is suppressed at the time of pressing after electrode application. The average particle diameter D50 may be 9.5 μm or more, 10.0 μm or more, or 10.5 μm or more. Further, the average particle diameter D50 may be 13.5 μm or less, 13.0 μm or less, 12.5 μm or less, or 12.0 μm or less.

  The amount of residual alkali contained in the oxide-based positive electrode active material for a lithium ion battery according to the embodiment of the present invention is preferably 0.6% by mass or less, more preferably 0.4% by mass or less, It is more preferably 0.2% by mass or less.

The tap density of the oxide-based positive electrode active material for a lithium ion battery according to the embodiment of the present invention is preferably 1.4 g / cm ³ or more. According to such a configuration, a battery having a high energy density per volume can be configured. The tap density is more preferably 1.5 g / cm ³ or more, and still more preferably 1.6 g / cm ³ or more.

(Method for producing precursor of oxide-based positive electrode active material for lithium ion battery)
Precursor exemplary oxide-based positive electrode active material for a lithium ion battery according to the embodiment of the present invention, composition formula _{(Ni x Co y Mn 1-} xy) CO 3
(Wherein 0.16 ≦ x ≦ 0.17 and 0.16 ≦ y ≦ 0.17).
The method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention uses an aqueous solution containing an aqueous solution of nickel salt, cobalt salt, manganese salt, aqueous ammonia and carbonate as a reaction solution, It includes a step of performing a crystallization reaction while controlling the pH in the reaction solution at 9.6 to 10.5, the ammonium ion concentration at 2.5 g / L or less, and the solution temperature at 40 to 60 ° C.

  The method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention is thus controlled while controlling the pH, ammonium ion concentration, and liquid temperature in the reaction solution within a certain range. A heavy precursor having a low alkali amount and an average particle diameter D50 of 7.0 to 17.0 μm can be produced by this method. By using the precursor, an oxide-based positive electrode active material that can achieve both a low alkali amount and a high energy density can be produced even with a composition having a high Li ratio.

  In the method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention, the pH, ammonium ion concentration, and liquid temperature in the reaction solution are controlled within a certain range as described above. For this purpose, for example, three raw materials, (1) a mixed aqueous solution of nickel salt, cobalt salt, and manganese salt, (2) aqueous ammonia, and (3) an aqueous carbonate solution, are put in a reaction vessel. At the same time, a small amount is continuously fed and reacted. Specifically, in a 10 L reactor, (1) a mixed aqueous solution of nickel salt, cobalt salt and manganese salt is 0.60 L / h, (2) aqueous ammonia is 0.04 L / h, and (3) carbonic acid. An aqueous salt solution may be simultaneously supplied at a rate of 1.2 L / h to cause a crystallization reaction. Thus, by continuously supplying the three raw materials to the reaction tank in small amounts at a time and reacting them, fluctuations in the pH and ammonia concentration of the reaction liquid in the reaction tank are suppressed well, and the pH in the reaction liquid is reduced to 9. It becomes easy to control 6 to 10.5 and ammonium ion concentration to 2.5 g / L or less.

  Examples of the aqueous solution of carbonate in (3) above include aqueous solutions using carbonate salts such as aqueous sodium carbonate solution, aqueous potassium carbonate solution, aqueous sodium bicarbonate solution, and aqueous potassium hydrogen carbonate solution.

  In the method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention, the crystallization reaction is performed while controlling the pH in the reaction solution to 9.6 to 10.5. Is less than 9.6, the particle size of the precursor produced is too large, and there is a risk of breaking through the current collector foil during rolling of the positive electrode active material to the electrode. Moreover, when pH exceeds 10.5, there exists a possibility that the particle size of the precursor to produce | generate may become small too much and the tap density of a positive electrode active material may fall. The pH in the reaction solution may be 9.8 or more, 10.0 or more, 10.3 or less, or 10.1 or less.

  In the method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention, the crystallization reaction is performed while controlling the ammonium ion concentration in the reaction solution to 2.5 g / L or less. According to such a structure, the residual alkali amount of the oxide type positive electrode active material for lithium ion batteries produced using the produced | generated precursor is controllable to 0.7 mass% or less. The ammonium ion concentration in the reaction solution is preferably 2.0 g / L or less, more preferably 1.5 g / L or less, and even more preferably 1.0 g / L or less.

  In the method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention, the crystallization reaction is performed while controlling the liquid temperature of the reaction liquid at 40 to 60 ° C. If the temperature is lower than 60 ° C., the particle size of the precursor to be produced becomes too small, and the tap density of the positive electrode active material may be lowered. There is a fear. The liquid temperature of the reaction solution may be 45 ° C. or higher, or 50 ° C. or higher. Further, the temperature of the reaction solution may be 55 ° C. or less.

(Method for producing oxide-based positive electrode active material for lithium ion battery)
The method for producing an oxide-based positive electrode active material for a lithium ion battery according to an embodiment of the present invention includes a precursor produced by the above-described method and a sum of the number of atoms of metals (Me) made of Ni, Co, and Mn. Mixing so that the ratio (Li / Me) to the number of lithium atoms is 1.40 to 1.48 to form a lithium mixture, and firing the lithium mixture in an air atmosphere at 750 to 950 ° C. Process. If the lithium mixture is baked at a temperature lower than 750 ° C., the precursor and the lithium compound may not be sufficiently reacted. If baked at a temperature higher than 950 ° C., a problem of oxygen desorption from the crystal structure may occur.

  In the solid solution positive electrode active material of Patent Document 1, nucleation is first performed with an aqueous transition metal solution and aqueous ammonia, and then an aqueous sodium carbonate solution is added. In this case, since the nuclei to be produced are relatively small and many are produced, they immediately agglomerate into secondary particles immediately after the production, and then an aqueous sodium carbonate solution is added thereto. By doing so, the agglomerated nuclei grow in the irregular shape. In such a case, it is useful for improving the electrode reaction speed in the point that there are many gaps in the generated secondary particles. As a result, it has been unavoidable that the problem of increased alkali occurs. On the other hand, according to the manufacturing method according to the embodiment of the present invention, an aqueous solution containing an aqueous solution of nickel salt, cobalt salt, manganese salt, aqueous ammonia and carbonate is used as a reaction solution, and the pH in the reaction solution is 9. .6 to 10.5, the ammonium ion concentration is 2.5 g / L or less, and the precursor is prepared by performing the crystallization reaction while controlling the liquid temperature at 40 to 60 ° C., so it reacts well during firing. A precursor of a transition metal to be prepared, which is mixed with a lithium source and a molar ratio of Li / (Ni + Co + Mn) = 1.40 to 1.48 and fired at 750 to 950 ° C. for 2 to 12 hours. Thus, an oxide-based positive electrode active material having a low residual alkali amount and high energy density can be produced.

(Configuration of positive electrode for lithium ion battery and lithium ion battery using the same)
The positive electrode for a lithium ion battery according to an embodiment of the present invention is, for example, an aluminum positive electrode mixture prepared by mixing an oxide-based positive electrode active material for a lithium ion battery having the above-described configuration, a conductive additive, and a binder. It has a structure provided on one side or both sides of a current collector made of foil or the like. Moreover, the lithium ion battery which concerns on embodiment of this invention is equipped with the positive electrode for lithium ion batteries of such a structure. The lithium ion battery according to the embodiment of the present invention may be a liquid lithium ion battery or an all solid lithium ion battery.

  Examples for better understanding of the present invention and its advantages are provided below, but the present invention is not limited to these examples.

As shown below, oxide positive electrode active materials were prepared in Examples 1 to 11 and Comparative Examples 1 to 4, respectively, and the average particle diameter D50, the residual alkali amount, and the tap density (density after 1500 taps) Further, the discharge capacity and electrode density of a lithium ion battery using the positive electrode active material were measured, and the energy density was calculated by (electrode density) × (discharge capacity). Moreover, it confirmed that the powder of the obtained oxide type positive electrode active material was a layered structure by XRD diffraction, and Li, Ni, and the like by an inductively coupled plasma emission spectrometer (ICP-OES) and an ion chromatography method. The contents of Mn and Co were measured. From the analysis results, a, b, and c when the positive electrode active material was represented by a metal composition of Li _a Ni _b Co _c Mn _1-bc were determined.

-Residual alkali amount-
The amount of residual alkali was determined by dispersing 1 g of the produced positive electrode active material powder in 50 mL of pure water, stirring and filtering for 10 minutes, and then mixing the mixture of 10 mL of filtrate and 15 mL of pure water with 0.1 N HCl. Determined by measuring the potential difference.

-Battery characteristics-
The obtained positive electrode active material was weighed with a conductive material (acetylene black) and a binder (polyvinylidene fluoride) at a ratio of 80:10:10, and the binder was dissolved in an organic solvent (N-methylpyrrolidone). A positive electrode active material and a conductive material were mixed to form a slurry, applied onto an Al foil, dried, and pressed at 45 kN to obtain a positive electrode. Subsequently, a 2032 type coin cell for evaluation with Li as the counter electrode was prepared, and the initial characteristics of the battery at 25 ° C. (1M-LiPF ₆ dissolved in EC-DMC (volume ratio 1: 1) in the electrolytic solution ( Charge capacity, discharge capacity, charge / discharge characteristics) were measured. The charging / discharging conditions are charging conditions: CC / CV 4.8V, 0.1C, discharging conditions: CC 0.05C, 3V.

-Electrode density-
From the weight of the positive electrode measured by a micrometer, the weight obtained by subtracting the weight of only the Al foil measured in advance from the weight of the positive electrode that was applied on the Al foil prepared above and dried and pressed at 45 kN to form a positive electrode was used. The thickness obtained by subtracting the thickness of the Al foil measured in advance was defined as the electrode thickness, and the electrode volume was calculated from the obtained electrode thickness and electrode area. The electrode density was calculated from electrode weight / electrode volume.

Example 1
A 1.5 mol / L aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared, and a predetermined amount of each aqueous solution was weighed so that Ni: Co: Mn = 0.167: 0.167: 0.666. The mixed solution was adjusted and fed to a reaction vessel in which a stirring blade was installed inside the container.
Next, while operating the stirring blade, the aqueous ammonia and 1.3 mol / L aqueous sodium carbonate solution were added so that the pH of the mixed solution in the reaction vessel was 10.5 and the ammonium ion concentration was 2.5 g / L. Ni-Co-Mn complex carbonate was co-precipitated by crystallization method. At this time, the temperature of the mixed solution in the reaction vessel was kept warm with a water jacket so as to be 40 ° C.
Further, nitrogen gas was introduced into the reaction vessel in order to prevent oxidation of the coprecipitate generated by the reaction. As long as the gas introduced into the reaction tank is a gas that does not promote oxidation, such as helium, neon, argon, carbon dioxide, etc., it can be used without being limited to the nitrogen gas described above.
The coprecipitated precipitate was suctioned and filtered, washed with pure water, and dried at 120 ° C. for 12 hours. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 7.8 μm.
Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn in the composite carbonate compound particles is Me, the ratio (Li / Me) to the number of lithium (Li) atoms is 1.44. Mixing with lithium hydroxide, mixing in an automatic mortar for 30 minutes, filling the mixed powder into an alumina mortar, firing in a muffle furnace at 900 ° C. for 8 hours in the air, and oxide-based positive electrode active material Was made. The positive electrode active material had an average particle diameter D50 of 10.0 μm, a residual alkali amount as low as 0.29 mass%, and a tap density as high as 1.5 g / cc.
Next, the positive electrode active material, the conductive material acetylene black, and the binder polyvinylidene fluoride are weighed in a ratio of 90: 5: 5, and the polyvinylidene fluoride binder is used as an organic solvent (N-methylpyrrolidone). It melt | dissolved, mixed with the said positive electrode active material and the electrically conductive material, it was made into a slurry, apply | coated on the aluminum foil, it was made to dry, and it press-molded, and formed the positive electrode.
Next, as a battery structure, a 2032 type coin cell for evaluation was prepared using a negative electrode as a Li metal foil, and 1M-LiPF ₆ was dissolved in EC-DMC (volume ratio 1: 1) in an electrolytic solution. The battery initial characteristics of the charge capacity were measured at ° C. As a result, the discharge capacity of the battery structure was 253 mAh / g, and showed a good energy density.

(Example 2)
Example 2 is the same as Example 1 except that the composite carbonate compound particles and lithium hydroxide in Example 1 are mixed and the temperature for firing in the muffle furnace is 850 ° C. for 8 hours in the atmosphere. Under the conditions, an oxide-based positive electrode active material for a lithium ion battery was produced. As a result, the average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles was 7.8 μm. The average particle diameter D50 of the positive electrode active material was 9.4 μm, the residual alkali amount was as low as 0.40 mass%, and the tap density was as high as 1.4 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 2 was 265 mAh / g, and showed a good energy density.

(Example 3)
In Example 3, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn of the composite carbonate compound particles in Example 1 is Me, the ratio (Li / Me) to the number of lithium atoms is 1.48. An oxide-based positive electrode active material for a lithium ion battery was produced under the same conditions as in Example 1 except that. As a result, the average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles was 7.8 μm. The average particle diameter D50 of the positive electrode active material was 9.5 μm, the residual alkali amount was as low as 0.50% by mass, and the tap density was as high as 1.4 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 3 was 250 mAh / g, and showed a good energy density.

Example 4
In Example 4, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn of the composite carbonate compound particles in Example 1 is Me, the ratio (Li / Me) to the number of lithium atoms is 1.48. An oxide-based positive electrode active material for a lithium ion battery was produced under the same conditions as in Example 1 except that the temperature for firing in the muffle furnace was 850 ° C. As a result, the average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles was 7.8 μm. The average particle diameter D50 of the positive electrode active material was 9.1 μm, the residual alkali amount was as low as 0.62% by mass, and the tap density was as high as 1.4 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 4 was 257 mAh / g, and showed a good energy density.

(Example 5)
In Example 5, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn of the composite carbonate compound particle in Example 1 is Me, the ratio (Li / Me) to the number of lithium atoms is 1.44. An oxide-based positive electrode active material for a lithium ion battery was produced under the same conditions as in Example 1 except that the temperature for firing in the muffle furnace was 750 ° C. As a result, the average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles was 7.8 μm. The average particle diameter D50 of the positive electrode active material was 9.2 μm, the residual alkali amount was as low as 0.55 mass%, and the tap density was as high as 1.4 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 5 was 251 mAh / g, and showed a good energy density.

(Example 6)
In Example 6, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn of the composite carbonate compound particles in Example 1 is Me, the ratio to the number of lithium atoms (Li / Me) is 1.44. An oxide-based positive electrode active material for a lithium ion battery was produced under the same conditions as in Example 1 except that the temperature for firing in the muffle furnace was 800 ° C. As a result, the average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles was 7.8 μm. The average particle diameter D50 of the positive electrode active material was 9.4 μm, the residual alkali amount was as low as 0.49 mass%, and the tap density was as high as 1.4 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 6 was 262 mAh / g, and showed a good energy density.

(Example 7)
In Example 7, the mixing ratio of each aqueous solution of the coprecipitation reaction in Example 1 was adjusted to be Ni: Co: Mn = 0.17: 0.17: 0.66, and the pH of the mixed solution was 9 .6, without adding ammonia, the temperature of the mixed solution in the coprecipitation reaction tank was changed to 60 ° C. to perform coprecipitation. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 16.1 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn in the composite carbonate compound particles is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.40. And was fired in the air at 900 ° C. for 8 hours in a muffle furnace to prepare a positive electrode active material. This positive electrode active material had an average particle diameter D50 of 13.9 μm, a residual alkali amount as low as 0.32 mass%, and a tap density as high as 1.5 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 7 was 271 mAh / g, and showed a good energy density.

(Example 8)
In Example 8, the mixing ratio of each aqueous solution in the coprecipitation reaction in Example 1 was adjusted to be Ni: Co: Mn = 0.170: 0.170: 0.660, and the pH of the mixed solution was 9 .6, without adding ammonia, the temperature of the mixed solution in the coprecipitation reaction tank was changed to 60 ° C. to perform coprecipitation. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 16.1 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn of the composite carbonate compound particles is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.40. And baked in a muffle furnace at 850 ° C. for 8 hours in the air to prepare a positive electrode active material. This positive electrode active material had an average particle diameter D50 of 12.8 μm, a residual alkali amount as low as 0.40 mass%, and a tap density as high as 1.5 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 8 was 275 mAh / g, and showed a good energy density.

Example 9
In Example 9, the mixing ratio of each aqueous solution of the coprecipitation reaction in Example 1 was adjusted to be Ni: Co: Mn = 0.160: 0.160: 0.680, and the pH of the mixed solution was 9 .6, without adding ammonia, the temperature of the mixed solution in the coprecipitation reaction tank was changed to 60 ° C. to perform coprecipitation. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 16.1 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn in the composite carbonate compound particles is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.44. And was fired in the air at 900 ° C. for 8 hours in a muffle furnace to prepare a positive electrode active material. This positive electrode active material had an average particle diameter D50 of 13.8 μm, a residual alkali amount as low as 0.47% by mass, and a tap density as high as 1.5 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 9 was 261 mAh / g, and showed a good energy density.

(Example 10)
In Example 10, the mixing ratio of each aqueous solution of the coprecipitation reaction in Example 1 was adjusted to be Ni: Co: Mn = 0.160: 0.160: 0.680, and the pH of the mixed solution was 9 .6, without adding ammonia, the temperature of the mixed solution in the coprecipitation reaction tank was changed to 60 ° C. to perform coprecipitation. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 16.1 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn in the composite carbonate compound particles is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.44. And was fired in the air at 850 ° C. for 8 hours in a muffle furnace to produce a positive electrode active material. This positive electrode active material had an average particle diameter D50 of 12.6 μm, a residual alkali amount as low as 0.46% by mass, and a tap density as high as 1.6 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 10 was 273 mAh / g, and showed a good energy density.

(Example 11)
In Example 11, the mixing ratio of each aqueous solution of the coprecipitation reaction in Example 1 was adjusted to be Ni: Co: Mn = 0.160: 0.160: 0.680, and the pH of the mixed solution was 9 .6, without adding ammonia, the temperature of the mixed solution in the coprecipitation reaction tank was changed to 60 ° C. to perform coprecipitation. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 16.1 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn in the composite carbonate compound particles is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.40. And was fired in the air at 950 ° C. for 8 hours in a muffle furnace to produce a positive electrode active material. This positive electrode active material had an average particle diameter D50 of 13.8 μm, a residual alkali amount as low as 0.25% by mass, and a tap density as high as 1.6 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Example 11 was 255 mAh / g, and showed a good energy density.

(Comparative Example 1)
In Comparative Example 1, Ni: Co: Mn = 0.160: 0.160: 0.680 was adjusted in the coprecipitation reaction in Example 1, and the pH of the mixed solution was 10.1 and ammonia was added. Without co-precipitation, the temperature of the mixed solution in the coprecipitation reactor was set to 40 ° C. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 11.5 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn of the composite carbonate compound particle is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.20. And was fired in the air at 850 ° C. for 8 hours in a muffle furnace to produce a positive electrode active material. The average particle diameter D50 of this positive electrode active material is 9.8 μm, and since the mixing ratio of lithium hydroxide is small, the residual alkali amount is as low as 0.09 mass%, and the lithium ratio is low, so that the crystallinity The tap density was as low as 1.2 g / cc, which was small compared to the examples.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Comparative Example 1 was 135 mAh / g, and a good energy density could not be obtained.

(Comparative Example 2)
In Comparative Example 2, Ni: Co: Mn = 0.160: 0.160: 0.680 was adjusted in the coprecipitation reaction in Example 1, and the pH of the mixed solution was 10.1 and ammonia was added. Without co-precipitation, the temperature of the mixed solution in the coprecipitation reactor was set to 40 ° C. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 11.5 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn in the composite carbonate compound particles is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.52. And was fired in the air at 850 ° C. for 8 hours in a muffle furnace to produce a positive electrode active material. This positive electrode active material had an average particle diameter D50 of 9.3 μm, a residual alkali amount as high as 0.77% by mass, and a tap density of 1.4.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for lithium ion battery prepared in Comparative Example 2 is as low as 235 mAh / g, and the amount of residual alkali is large. It is considered that a decrease in discharge capacity due to gelation of the system positive electrode active material occurred, and a good energy density could not be obtained.

(Comparative Example 3)
In Comparative Example 3, Ni: Co: Mn = 0.160: 0.160: 0.680 was adjusted in the coprecipitation reaction in Example 1, and the pH of the mixed solution was 10.1 and ammonia was added. Without co-precipitation, the temperature of the mixed solution in the coprecipitation reactor was set to 40 ° C. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 11.5 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn in the composite carbonate compound particles is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.56. And was fired in the air at 850 ° C. for 8 hours in a muffle furnace to produce a positive electrode active material. The positive electrode active material had an average particle diameter D50 of 10.7 μm, a residual alkali amount as high as 0.86% by mass, and a tap density of 1.3 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Comparative Example 3 was 215 mAh / g, and a good energy density could not be obtained.

(Comparative Example 4)
In Comparative Example 4, Ni: Co: Mn = 0.160: 0.160: 0.680 was adjusted in the coprecipitation reaction in Example 1, and the pH of the mixed solution was 10.1 and ammonia was added. Without co-precipitation, the temperature of the mixed solution in the coprecipitation reactor was set to 40 ° C. The average particle diameter D50 of the Ni—Co—Mn composite carbonate compound particles thus produced was 11.5 μm. Next, when the sum of the number of atoms of the metal composed of Ni, Co, and Mn in the composite carbonate compound particles is Me, the lithium hydroxide is adjusted so that the ratio (Li / Me) to the number of lithium atoms is 1.70. And was fired in the air at 850 ° C. for 8 hours in a muffle furnace to produce a positive electrode active material. This positive electrode active material had an average particle diameter D50 of 11.5 μm, a residual alkali amount as high as 1.38% by mass, and a tap density of 1.4 g / cc.
The discharge capacity of the battery structure made of the oxide-based positive electrode active material for a lithium ion battery produced in Comparative Example 4 was 189 mAh / g, and a good energy density could not be obtained.
Test conditions and evaluation results according to Examples 1 to 11 and Comparative Examples 1 to 4 are shown in Tables 1 and 2.

Claims (8)

The metal composition is Li _a Ni _b Co _c Mn _1-bc
(In the formula, 1.40 ≦ a ≦ 1.48, 0.16 ≦ b ≦ 0.17, 0.16 ≦ c ≦ 0.17)
An oxide-based positive electrode active material for a lithium ion battery, wherein the residual alkali content is 0.7% by mass or less.   2. The oxide-based positive electrode active material for a lithium ion battery according to claim 1, wherein the average particle diameter D50 is 9.0 to 14.0 μm. ^{3. The} oxide-based positive electrode active material for a lithium ion battery according to claim 1, wherein the tap density is 1.4 g / cm ³ or more. An aqueous solution containing an aqueous solution of nickel salt, cobalt salt, manganese salt, aqueous ammonia and carbonate is used as a reaction solution, the pH in the reaction solution is 9.6 to 10.5, and the ammonium ion concentration is 2.5 g / L or less. , Including a step of performing a crystallization reaction while controlling the liquid temperature at 40 to 60 ° C.,
Composition formula _{(Ni x Co y Mn 1-} xy) CO 3
(In formula, it is 0.16 <= x <= 0.17, 0.16 <= y <= 0.17.) The manufacturing method of the precursor of the oxide type positive electrode active material for lithium ion batteries is represented.   The method for producing a precursor of an oxide-based positive electrode active material for a lithium ion battery according to claim 4, wherein the average particle diameter D50 of the precursor is 7.0 to 17.0 μm. 6. The precursor produced by the method according to claim 4 or 5, wherein the ratio (Li / Me) of the sum of the number of atoms of metal (Me) made of Ni, Co and Mn to the number of atoms of lithium is 1. Mixing to form 40 to 1.48 to form a lithium mixture;
Baking the lithium mixture at 750 to 950 ° C. in an air atmosphere;
The manufacturing method of the oxide type positive electrode active material for lithium ion batteries containing.   The positive electrode for lithium ion batteries provided with the oxide type positive electrode active material for lithium ion batteries as described in any one of Claims 1-3.   The lithium ion battery provided with the positive electrode for lithium ion batteries of Claim 7.