KR20190132633A - Method for producing lithium nickel composite oxide - Google Patents

Abstract

The method for producing a lithium nickel composite oxide is a method for producing a lithium nickel composite oxide represented by the general formula (I), which includes a mixing step of mixing a lithium compound and a nickel-containing metal composite compound to obtain a mixture, and firing the mixture. And a post-treatment step including a firing step of obtaining a fired product and a washing step of washing the fired product, wherein the mixing step includes a molar ratio of lithium contained in the lithium compound and a metal element in the nickel-containing metal composite compound ( Li / Me) is mixed so that the ratio exceeds 1, and the total amount of the residual sulfuric acid root and the residual lithium carbonate in the lithium nickel composite oxide obtained after the post-treatment step is 0.3% by mass or less, and the content of sodium is 50 ppm. It includes the process of processing so that it becomes the following.

Description

Method for producing lithium nickel composite oxide

The present invention relates to a method for producing a lithium nickel composite oxide.

This application claims priority in March 31, 2017 based on Japanese Patent Application No. 2017-072868 for which it applied to Japan, and uses the content for it here.

Lithium nickel composite oxide is used as a positive electrode active material for lithium secondary batteries (hereinafter may be described as a "positive electrode active material"). Lithium secondary batteries have already been put to practical use not only in small power supplies such as mobile phone applications and notebook PC applications, but also in medium-sized and large power supplies such as automobile applications and electric power storage applications.

As a manufacturing method of a lithium nickel complex oxide, the method provided with the manufacturing process of a lithium nickel complex oxide precursor, the mixing process of a lithium compound and the said precursor, a baking process, and the washing process after a baking process is known (for example, a patent document 1 to 3).

International Publication No. 2013/015007 International Publication No.2014 / 115380 International Publication No. 2014/189108

The washing process after the baking process is a process for the purpose of removing impurities. However, depending on the washing method, in a lithium secondary battery using a lithium nickel composite oxide as the positive electrode active material, the output at a high current rate at a high voltage may decrease. For example, there is a problem that impurities are left in the case of insufficient washing, lithium is eluted in the case of over-cleaning, and battery characteristics are lowered.

This invention is made | formed in view of the said situation, and makes it a subject to provide the manufacturing method of the lithium nickel composite oxide with high output at the high current rate at high voltage.

That is, this invention includes invention of following [1]-[9].

[1] A method for producing a lithium nickel composite oxide represented by the following General Formula (I), comprising: a mixing step of mixing a lithium compound and a nickel-containing metal composite compound to obtain a mixture, and firing the mixture to fire a fired product It has a post-processing process including the process and the washing process of washing a baking material, In the said mixing process, the molar ratio (Li / Me) of lithium contained in the said lithium compound, and the metal element in a nickel containing metal composite compound is 1 And the total amount of residual sulfate sulfate and residual lithium carbonate in the lithium nickel composite oxide obtained after the post-treatment step was 0.3 mass% with respect to the total mass of the lithium nickel composite oxide. And a step of treating the sodium content to be 50 ppm or less with respect to the total mass of the lithium nickel composite oxide. Method for producing a lithium nickel composite oxide.

Li [Li _x (Ni _(1-yzw) Co _y Mn _z M _w ) _1-x ] O ₂ ... (I)

In formula (I), 0 <x <0.2, 0 <y <0.5, 0 <z <0.8, 0 <w <0.1, y + z + w <1, M is Fe, Cu, Ti, Mg, Al Or at least one metal selected from the group consisting of W, B, Mo, Nb, Zn, Sn, Zr, Ga and V.)

[2] The method for producing a lithium nickel composite oxide according to [1], wherein in formula (I), y + z + w ≦ 0.3.

[3] The method for producing a lithium nickel composite oxide according to [1] or [2], wherein the firing temperature is 300 ° C or more and 1000 ° C or less.

[4] The method for producing a lithium nickel composite oxide according to any one of [1] to [3], wherein the post-treatment step includes a drying step of drying the obtained lithium nickel composite oxide after the washing step.

[5] The method for producing a lithium nickel composite oxide according to any one of [1] to [3], wherein the post-treatment step includes a refiring step of refiring the obtained lithium nickel composite oxide after the washing step.

[6] The method for producing a lithium nickel composite oxide according to [4], wherein the post-treatment step includes a refiring step of refiring the obtained lithium nickel composite oxide after the drying step.

[7] In the post-treatment step, the lithium nickel composite oxide obtained after the washing step is mixed with a compound of at least one element selected from the group consisting of aluminum, boron, titanium, zirconium, and tungsten, The manufacturing method of the lithium nickel complex oxide in any one of [1]-[3] including the coating process which coat | covers the surface with the compound of the said element.

[8] The post-treatment step of [1] to [3], wherein the lithium nickel composite oxide and the aluminum compound obtained after the washing step are mixed, and the coating step of coating the aluminum compound on the surface of the lithium nickel composite oxide is carried out. The manufacturing method of the lithium nickel complex oxide as described in any one.

[9] In the post-treatment step, after the drying step, the obtained lithium nickel composite oxide and a compound of at least one element selected from the group consisting of aluminum, boron, titanium, zirconium, and tungsten are mixed to form a lithium nickel composite oxide. The manufacturing method of the lithium nickel composite oxide as described in [4] including the coating | covering process which coat | covers the surface of this with the compound of the said element.

[10] The lithium nickel composite according to [4], wherein the post-treatment step includes a coating step of mixing the lithium nickel composite oxide and the aluminum compound obtained after the drying step and coating the surface of the lithium nickel composite oxide with an aluminum compound. Method for preparing oxides.

[11] In the post-treatment step, the total amount of residual sulfate and lithium carbonate in the lithium nickel composite oxide obtained after the drying step is 0.6% by mass or less with respect to the total mass of the lithium nickel composite oxide, and the content of sodium The manufacturing method of the lithium nickel composite oxide as described in any one of [6]-[10] which processes so that it may become 50 ppm or less with respect to the total mass of a lithium nickel composite oxide.

According to the present invention, a method for producing a lithium nickel composite oxide having a high output at a high current rate at a high voltage can be provided.

1: A is a schematic block diagram which shows an example of a lithium ion secondary battery.
1B is a schematic configuration diagram showing an example of a lithium ion secondary battery.

<Method for producing lithium nickel composite oxide>

Some aspects of this invention are a manufacturing method of the lithium nickel complex oxide represented by the following general formula (I). This embodiment is a post-process including a mixing step of mixing a lithium compound and a nickel-containing metal composite compound to obtain a mixture, a firing step of firing the mixture to obtain a fired product, and a washing step of washing the fired product. Has a process.

In other words, some embodiments of the present invention provide a post-treatment process including mixing a lithium compound and a nickel-containing metal composite compound to obtain a mixture, firing the mixture to obtain a fired product, and washing the fired product. Has

In the present embodiment, the mixing step is mixed so that the molar ratio (Li / Me) of the lithium contained in the lithium compound and the metal element in the nickel-containing metal composite compound is a ratio exceeding one.

According to the production method of the present embodiment, the total amount of the residual sulfate sulfate and residual lithium carbonate in the lithium nickel composite oxide obtained after the post-treatment step is 0.3 mass% or less with respect to the total mass of the lithium nickel composite oxide, and the content of sodium It includes the process of processing so that it may be 50 ppm or less with respect to the gross mass of a lithium nickel complex oxide.

In addition, in this specification, "the total amount of residual sulfate sulfate and residual lithium carbonate in a lithium nickel composite oxide obtained after a post-processing process is 0.3 mass% or less with respect to the total mass of a lithium nickel composite oxide, and content of sodium is lithium 50 ppm or less with respect to the total mass of the nickel composite oxide ”means that impurities such as residual sulfate, residual lithium carbonate and sodium do not enter the crystal structure of the lithium nickel composite oxide obtained after the post-treatment step. It means that impurities exist outside the crystal structure. In other words, the residual nickel sulfate, residual lithium carbonate, and sodium may be attached to the surface of the lithium nickel composite oxide.

Li [Li _x (Ni _(1-yzw) Co _y Mn _z M _w ) _1-x ] O ₂ ... (I)

In formula (I), 0 <x <0.2, 0 <y <0.5, 0 <z <0.8, 0 <w <0.1, y + z + w <1, M is Fe, Cu, Ti, Mg, Al Or at least one metal selected from the group consisting of W, B, Mo, Nb, Zn, Sn, Zr, Ga and V.)

The amount of residual sulfate root relative to the total mass of the lithium nickel composite oxide in the lithium nickel composite oxide obtained after the post-treatment step is, after dissolving the powder of the lithium nickel composite oxide in hydrochloric acid, followed by an inductively coupled plasma luminescence analyzer (S.I. It can measure using Nanotechnology Co., Ltd. product, SPS3000).

The amount of residual lithium carbonate with respect to the total mass of a lithium nickel complex oxide in the lithium nickel complex oxide obtained after a post-processing process can be calculated | required by the neutralization titration method shown below.

20 g of lithium nickel composite oxide and 100 g of pure water are put in a 100 ml beaker and stirred for 5 minutes. After stirring, the lithium nickel composite oxide is filtered, 0.1 mol / L hydrochloric acid is added dropwise to 60 g of the filtrate obtained, and the pH of the filtrate is measured with a pH meter. The appropriate amount of hydrochloric acid when the pH of the filtrate was 8.3 ± 0.1 was set to A ml, and the appropriate amount of hydrochloric acid when the pH was 4.5 ± 0.1 was B ml. Based on the following calculation formula, carbonic acid contained in the lithium nickel composite oxide Calculate the lithium concentration. In addition, the molecular weight (73.882) of lithium carbonate is calculated by setting the atomic weight of Li to 6.941, the atomic weight of C to 12, and the atomic weight of O to 16.

Lithium Carbonate Concentration (%) = 0.1 × (B-A) / 1000 × 73.882 / (20 × 60/100) × 100

The amount of sodium relative to the total mass of the lithium nickel composite oxide in the lithium nickel composite oxide obtained after the post-treatment step was determined by the inductively coupled plasma emission spectrometry using an inductively coupled plasma luminescence analyzer (SPS3000, manufactured by SAI Nanotechnology Co., Ltd.). Can be obtained by

In addition, general formula (I) does not contain H, C, S, and Na derived from residual sulfate sulfate, residual lithium carbonate, and sodium. This is because the residual sulfate sulfate, residual lithium carbonate and sodium contained in the lithium nickel composite oxide are not included in the crystal structure of the lithium nickel composite oxide.

EMBODIMENT OF THE INVENTION Hereinafter, preferable embodiment of the manufacturing method of the lithium nickel complex oxide of this invention is described.

`` First embodiment ''

1st Embodiment is a manufacturing method of the lithium nickel complex oxide represented by General formula (I), Comprising: The mixing process of mixing a lithium compound and a nickel containing metal composite compound, and obtaining a mixture, and calcining the said mixture, and obtaining a fired material The post-processing process including the baking process and the washing | cleaning process which wash | cleans the said baking material is provided in this order.

In other words, the present embodiment has a post-treatment step including mixing a lithium compound and a nickel-containing metal composite compound to obtain a mixture, firing the mixture to obtain a fired product, and washing the fired product. .

Hereinafter, each process is demonstrated.

[Mixing process]

The mixing step is a step of mixing the lithium compound and the nickel-containing metal composite compound to obtain a mixture. This step firstly comprises an essential metal composed of metals other than lithium compounds, that is, Ni, Co and Mn, and, as desired, Fe, Cu, Ti, Mg, Al, W, B, Mo, Nb. To prepare a nickel-containing metal composite compound containing any one or more of any one of Zn, Sn, Zr, Ga, and V, and mix the nickel-containing metal composite compound with a suitable lithium compound, and then calcining the resulting mixture. desirable. As a nickel containing metal composite compound, a nickel containing metal composite hydroxide or a nickel containing metal composite oxide is preferable. Below, a mixing process is demonstrated dividing into the manufacturing process of a nickel containing metal composite compound, and the manufacturing process of a lithium nickel complex oxide.

(Manufacturing process of nickel containing metal composite compound)

The nickel-containing metal composite compound can usually be produced by a known batch coprecipitation method or continuous coprecipitation method. Hereinafter, as a metal, the manufacturing method is explained in full detail, taking the nickel containing metal composite hydroxide containing nickel, cobalt, and manganese as an example.

The nickel-containing metal composite hydroxide is a co-precipitation method, in particular by the continuous method described in Japanese Laid-Open Patent Publication No. 2002-201028, by reacting a nickel salt solution, cobalt salt solution, manganese solution, and complexing agents, Ni _1- Nickel-containing metal composite hydroxides represented by _yz Co _y Mn _z (OH) ₂ (wherein, 0 <x ≦ 0.2, 0 <y ≦ 0.5, 0 <z ≦ 0.8) can be produced.

Although it does not specifically limit as nickel salt which is a solute of the said nickel salt solution, For example, any of nickel sulfate, nickel nitrate, nickel chloride, and nickel acetate can be used. As cobalt salt which is a solute of the said cobalt salt solution, any of cobalt sulfate, cobalt nitrate, cobalt chloride, and cobalt acetate can be used, for example. As manganese salt which is a solute of the said manganese salt solution, any of manganese sulfate, manganese nitrate, manganese chloride, and manganese acetate can be used, for example. The above metal salt is used in the ratio corresponding to the composition ratio of said Ni _1-yz Co _y Mn _z (OH) ₂ . That is, the amount of each metal salt is defined so that the molar ratio of nickel, cobalt, and manganese in the mixed solution containing the metal salt corresponds to (1-yz): y: z in the composition formula (I) of the lithium nickel composite oxide. .

Moreover, water is used as a solvent.

As the complexing agent, complexes can be formed with ions of nickel, cobalt, and manganese in an aqueous solution. Diamine tetraacetic acid, nitrilotriacetic acid, uracil diacetic acid, and glycine. The complexing agent does not need to be included as desired, and when the complexing agent is included, the amount of the complexing agent contained in the mixed solution containing the nickel salt solution, the cobalt salt solution, the manganese salt solution, the M salt solution and the complexing agent is, for example, For example, the molar ratio with respect to the sum total of the moles of metal salt is larger than 0 and is 2.0 or less.

During precipitation, alkali metal hydroxides (eg sodium hydroxide and potassium hydroxide) are added if necessary to adjust the pH value of the aqueous solution.

In addition to the nickel salt solution, cobalt salt solution, and manganese salt solution, when a complexing agent is continuously supplied to the reaction tank, nickel, cobalt, and manganese react to produce Ni _1-yz Co _y Mn _z (OH) ₂ . . At the time of reaction, the temperature of a reaction tank is controlled in the range of 20 degreeC or more and 80 degrees C or less, for example, 30 degreeC or more and 70 degrees C or less, pH value in a reaction tank is, for example, 40 degreeC measurement pH 9 or more and pH 13 or less, Preferably it is controlled in the range of pH 11 or more and pH 13 or less, and the substance in a reaction tank is stirred suitably. The reactor is of the type which overflows the formed reaction precipitate for separation.

Regarding the reaction conditions, depending on the size of the reaction tank to be used and the like, the reaction conditions may be optimized while monitoring various physical properties of the finally obtained lithium nickel composite oxide.

After the above reaction, the obtained reaction precipitate is washed with water and then dried to isolate the nickel-containing metal composite hydroxide as the nickel-containing metal composite compound. Moreover, you may wash | clean the reaction deposit obtained as needed with the alkaline solution containing weakly acidic water or sodium hydroxide or potassium hydroxide.

In addition, although the nickel containing metal composite hydroxide is manufactured in said example, you may prepare a nickel containing metal composite oxide. When preparing a nickel containing metal composite oxide, it can be prepared, for example by performing the process of contacting the said coprecipitation slurry and an oxidizing agent, or drying a nickel containing metal composite hydroxide, and then heat-processing.

(Manufacturing Process of Lithium Nickel Composite Oxide)

The nickel-containing metal composite oxide or nickel-containing metal composite hydroxide is dried and then mixed with a lithium compound. The drying conditions are not particularly limited, but for example, nickel-containing metal composite oxides or nickel-containing metal composite hydroxides are not oxidized and reduced (that is, conditions in which the oxide remains an oxide and the hydroxide remains a hydroxide). May be any of the conditions under which the nickel-containing metal composite hydroxide is oxidized (that is, under conditions where the hydroxide is oxidized to an oxide) and under conditions under which the nickel-containing metal composite compound is reduced (that is, under conditions where the oxide is reduced to hydroxide). In order to prevent oxidation and reduction, an inert gas such as nitrogen, helium and argon may be used. Oxygen or air may be used under the condition that the nickel-containing metal composite hydroxide is oxidized. Moreover, what is necessary is just to use reducing agents, such as hydrazine and sodium sulfite, in inert gas atmosphere as conditions for reducing a nickel containing metal composite oxide. As a lithium compound, any one of lithium carbonate, lithium nitrate, lithium sulfate, lithium acetate, lithium hydroxide, lithium oxide, lithium chloride, and lithium fluoride, or two or more thereof can be mixed and used.

After drying of a nickel containing metal composite oxide or a nickel containing metal composite hydroxide, you may classify suitably. The lithium compound and the nickel-containing metal composite compound described above are mixed so that the molar ratio (Li / Me) of the metal element in the lithium and nickel-containing metal composite compound in the lithium compound becomes a ratio exceeding one. In this embodiment, it mixes so that the ratio of the number-of-moles of lithium in a lithium compound, and the total number-of-moles of nickel, cobalt, manganese, and arbitrary metals contained in a nickel containing metal composite compound becomes a ratio exceeding 1.

[Firing process]

By baking the mixture of a nickel containing metal composite compound and a lithium compound, the baking powder which is a lithium nickel composite oxide is obtained. In addition, dry air, an oxygen atmosphere, an inert atmosphere, etc. are used for baking, and a some heating process is performed if necessary.

Although there is no restriction | limiting in particular as baking temperature of the mixture of the said nickel containing metal composite oxide or nickel containing metal composite hydroxide, and a lithium compound, It is preferable that it is 300 degreeC or more from a viewpoint which can prevent the fall of a charge capacity, and is 350 degreeC or more It is more preferable, and it is still more preferable that it is 400 degreeC or more. Moreover, although there is no restriction | limiting in particular, From a viewpoint of obtaining the lithium nickel complex oxide of the target composition which can prevent volatilization of Li, it is preferable that it is 1000 degrees C or less, and it is more preferable that it is 950 degrees C or less.

Volatilization of Li can be controlled by firing temperature.

The upper limit and the lower limit of the firing temperature can be arbitrarily combined. For example, it is preferable that baking temperature is 300 degreeC or more and 1000 degrees C or less, It is more preferable that they are 350 degreeC or more and 950 degrees C or less, It is still more preferable that they are 400 degreeC or more and 950 degrees C or less.

It is preferable to make baking time into the sum total time from a temperature start to a month until a temperature maintenance is complete | finished, for 1 hour or more and 30 hours or less. If total time is 30 hours or less, volatilization of Li can be prevented and deterioration of battery performance can be prevented.

If the total time is 1 hour or more, the development of the crystal proceeds well, and the battery performance can be improved.

It is preferable that the time from the temperature start to the calcination temperature is 0.5 hours or more and 20 hours or less. A more uniform lithium nickel composite oxide can be obtained as long as the time from the start of temperature rise until the firing temperature is in this range. Moreover, it is preferable that time from reaching baking temperature until completion | finish of temperature maintenance is 0.5 hour or more and 20 hours or less. If the time from reaching the firing temperature to the end of the temperature holding is within this range, the development of the crystal proceeds better, and the battery performance can be further improved.

Moreover, it is also effective to perform preliminary baking before said baking. It is preferable to perform the temperature of such preliminary baking for 1 to 10 hours in 300-850 degreeC. By performing preliminary baking, the baking time can be shortened in some cases.

By performing a baking process on said conditions, volatilization of lithium can be suppressed. As a result, a lithium nickel composite oxide having a high output at a high current rate at a high voltage can be obtained.

[Post-processing process]

The post-treatment step includes a washing step of washing the calcined product obtained in the firing step, and the sum of the residual sulfate root and the residual lithium carbonate of the lithium nickel composite oxide obtained after the post-treatment step is based on the total mass of the lithium nickel composite oxide. 0.3 mass% or less, and it is the process of postprocessing so that sodium may be 50 ppm or less with respect to the gross mass of a lithium nickel complex oxide.

[Cleaning process]

A washing | cleaning process mixes a washing | cleaning liquid and a baking material, forms a slurry, and wash | generates the baking material powder by stirring this slurry. In that case, although the density | concentration (slurry density | concentration) of the slurry which mixed the washing | cleaning liquid and the baking substance powder is not specifically limited, From the viewpoint of suppressing elution of Li, the mass of the baking substance powder with respect to a washing | cleaning liquid is adjusted to 50 g / L or more. It is preferable to adjust, and it is more preferable to adjust to 100 g / L or more.

Moreover, it is preferable to adjust the density | concentration (slurry density | concentration) of the slurry which mixed the washing | cleaning liquid and baking material powder to 2000 g / L or less from a viewpoint of having sufficient handling property, and to adjust to 1000 g / L or less desirable.

In short, it is preferable that the mass of the baking powder with respect to a washing | cleaning liquid is adjusted to 50 g / L or more and 2000 g / L or less, and, as for a slurry, it is more preferable to adjust to 100 g / L or more and 1000 g / L or less.

When Li is eluted by the washing step, Li / Me of the lithium nickel composite oxide, that is, the molar ratio of lithium (molar ratio of lithium to the total amount of metal elements except lithium) decreases, but the Li / Me decrease by adjusting the slurry concentration. Can be controlled.

It is preferable that it is 1-30 micrometers, and, as for the average secondary particle diameter of the baked material powder provided to a washing | cleaning process, it is more preferable that it is 3-20 micrometers. When the average secondary particle size of the fired powder is 1 to 30 µm, the contact area between the fired powder and the cleaning liquid is adjusted, and excessive elution of Li contained in the lithium nickel composite oxide can be suppressed.

The average secondary particle diameter of the fired powder can be measured using a laser diffraction scattering particle size distribution measuring device. Specifically, using a laser diffraction particle size distribution analyzer (Horiba, Ltd., model number: LA-950), 0.1 g of the fired powder was added to 50 ml of a 0.2% by mass aqueous solution of sodium hexamethaphosphate, and the fired powder was The dispersed liquid dispersion is obtained. Particle size distribution is measured about the obtained dispersion liquid, and a cumulative particle size distribution curve on a volume basis is obtained. In the obtained cumulative particle size distribution curve, the value of the particle diameter (D50) seen from the microparticle side at the time of 50% accumulation is made into the average secondary particle diameter of the fired powder.

As a washing | cleaning liquid used for a washing | cleaning process, water and an alkaline solution are mentioned, for example. In this embodiment, it is preferable that it is water.

Although washing | cleaning time is not specifically limited, From a viewpoint of fully removing an impurity, it is preferable to set it as 1 minute or more, and it is more preferable to set it as 5 minutes or more. Moreover, from a viewpoint of improving productivity, 60 minutes or less are preferable and 30 minutes or less are more preferable. In other words, the washing time is preferably 1 minute or more and 60 minutes or less, and more preferably 5 minutes or more and 30 minutes or less.

By performing a washing | cleaning process on said conditions, an impurity can fully be removed and it can suppress that a lithium elutes in a slurry. As a result, a lithium nickel composite oxide having a high output at a high current rate at a high voltage can be obtained.

In the present embodiment, "impurity" refers to sulfur-containing ions (residual sulfate roots) such as SO ₄ ^2- remaining on the surface of the particles contained in the lithium nickel composite oxide after the firing step, residual lithium carbonate, and pH control. The thing which the coprecipitation residue of the alkali metal to use remains.

When sulfate is used as a transition metal, the sulfate root resulting from this may remain. In this embodiment, the generation source of residual sulfate root as an impurity is not specifically limited, For example, even when a sulfate is not used, the sulfur containing compound etc. which remain on the surface of particle | grains etc. originate in various materials to be used for an impurity. Shall be.

In addition, when lithium carbonate as an impurity uses lithium carbonate as a lithium source (lithium compound), the residual lithium carbonate resulting from this is mentioned. In addition, even when lithium sources other than lithium carbonate are used, the lithium carbonate which may be generated by reaction with carbon dioxide in the air is also included in the "impurity".

Examples of sodium as impurities include sodium sulfate, sodium carbonate, sodium bicarbonate, sodium hydroxide, and the like as coprecipitation residues of alkali metals used for pH control.

In this embodiment, it is preferable to post-process so that the sum total of the residual sulfate sulfate and residual lithium carbonate of the lithium nickel complex oxide obtained after a post-process may be 0.27 mass% or less with respect to the total mass of a lithium nickel composite oxide, and it is 0.24 mass It is more preferable to post-process so that it may become% or less. Although the minimum of the sum total of the residual sulfate sulfate and residual lithium carbonate contained in the lithium nickel composite oxide obtained after a post-processing process is so preferable that it is small, it is about 0.03 mass% with respect to the gross mass of a lithium nickel composite oxide, for example.

Moreover, it is preferable to post-process sodium so that it may become 25 ppm or less with respect to the gross mass of a lithium nickel complex oxide, and it is more preferable to post-process so that it may become 15 ppm or less. Although the lower limit of the ratio of sodium contained in the lithium nickel composite oxide obtained after a post-treatment process is so preferable that it is small, it is about 5 ppm with respect to the total mass of a lithium nickel composite oxide, for example.

`` Second Embodiment ''

This embodiment has a drying process further after a washing | cleaning process in the post-processing process of the said 1st Embodiment. That is, the manufacturing method of the lithium nickel composite oxide of this embodiment has a mixing process, a baking process, and a post-processing process (washing process and a drying process) in this order. In other words, in the method for producing a lithium nickel composite oxide of the present embodiment, a lithium compound and a nickel-containing metal composite compound are mixed to obtain a mixture, the mixture is calcined to obtain a fired product, and the fired product is washed. And a post-treatment step including the step, wherein the post-treatment step further includes drying the washing.

The temperature and method for drying the lithium nickel composite oxide in the drying step are not particularly limited, but the drying temperature is preferably 30 ° C or higher, more preferably 40 ° C or higher, and 50 ° C or higher from the viewpoint of sufficiently removing moisture. More preferred.

Moreover, it is preferable that it is 300 degrees C or less from a viewpoint of preventing abnormality from forming in a surface, It is more preferable that it is 250 degrees C or less, It is further more preferable that it is 200 degrees C or less.

Here, the above shows what has a crystal structure different from the lithium nickel composite oxide of this embodiment, and shows the compound of rock salt structure like nickel oxide, for example.

`` Third embodiment ''

This embodiment has a refire process further after a washing | cleaning process in the post-processing process of the said 1st Embodiment. That is, the manufacturing method of the lithium nickel composite oxide of this embodiment has a mixing process, a baking process, and a post-processing process (a washing process and a recalcination process) in this order. In other words, in the method for producing a lithium nickel composite oxide of the present embodiment, a lithium compound and a nickel-containing metal composite compound are mixed to obtain a mixture, the mixture is calcined to obtain a fired product, and the fired product is washed. And a post-treatment step including the step, wherein the post-treatment step further includes recalculating the wash. The description about the mixing process, the baking process, and the washing process in this embodiment is the same as that in the said 1st Embodiment.

[Plastic process]

Although there is no restriction | limiting in particular as the baking temperature of the recalcination process of a lithium nickel complex oxide, It is preferable that it is 300 degreeC or more from a viewpoint which can prevent the fall of a charge capacity, It is more preferable that it is 350 degreeC or more, It is 400 degreeC or more More preferred. Moreover, although there is no restriction | limiting in particular, From a viewpoint of obtaining the lithium nickel complex oxide of the target composition which can prevent volatilization of Li, it is preferable that it is 1000 degrees C or less, and it is more preferable that it is 950 degrees C or less.

Volatilization of Li can be controlled by firing temperature.

The upper limit and the lower limit of the firing temperature can be arbitrarily combined. For example, it is preferable that the baking temperature of a refiring process is 300 degreeC or more and 1000 degrees C or less, It is more preferable that they are 350 degreeC or more and 950 degrees C or less, It is further more preferable that they are 400 degreeC or more and 950 degrees C or less.

The refiring time is preferably set to a total time of 1 hour or more and 30 hours or less from the start of the temperature rise until the temperature maintenance is completed. If total time is 30 hours or less, volatilization of Li can be prevented and deterioration of battery performance can be prevented.

If the total time is 1 hour or more, the development of the crystal proceeds well, and the battery performance can be improved.

It is preferable that the time from the temperature start to the calcination temperature is 0.5 hours or more and 20 hours or less. A more uniform lithium nickel composite oxide can be obtained as long as the time from the start of temperature rise until the firing temperature is in this range. Moreover, it is preferable that time from reaching baking temperature until completion | finish of temperature maintenance is 0.5 hour or more and 20 hours or less. If the time from reaching the firing temperature to the end of the temperature holding is within this range, the development of the crystal proceeds better, and the battery performance can be further improved.

Moreover, it is also effective to perform preliminary baking before said baking. It is preferable to perform the temperature of such preliminary baking for 1 to 10 hours in 300-850 degreeC.

In addition, by performing the refiring process under the above conditions, impurities such as lithium carbonate can be reduced.

In a post-treatment step having a washing step and a refiring step, the washing step and the refiring step can be carried out under the above conditions, whereby impurities can be sufficiently removed, and further, lithium can be prevented from leaching in the slurry in the washing step. Can be. As a result, a lithium nickel composite oxide having a high output at a high current rate at a high voltage can be obtained.

`` Fourth Embodiment ''

This embodiment has a refiring process further after a drying process in the post-processing process of the said 2nd Embodiment. That is, the manufacturing method of the lithium nickel composite oxide of 4th Embodiment has a mixing process, a baking process, and a post-processing process (a washing process, a drying process, and a recalcination process) in this order. In other words, in the method for producing a lithium nickel composite oxide of the present embodiment, a lithium compound and a nickel-containing metal composite compound are mixed to obtain a mixture, the mixture is calcined to obtain a fired product, and the fired product is washed. It has a post-processing process containing the thing, a post-processing process further includes drying the said washing | cleaning thing and recalcining the dry matter.

The description about the mixing process, the baking process, the washing process, the drying process, and the refiring process in this embodiment is the same as that in the said embodiment.

`` Fifth Embodiment ''

This embodiment has a coating | coating process further after a washing | cleaning process in the post-processing process of said 1st Embodiment. That is, the manufacturing method of the lithium nickel composite oxide of this embodiment has a mixing process, a baking process, and a post-processing process (washing process and a coating process) in this order. In other words, in the method for producing a lithium nickel composite oxide of the present embodiment, a lithium compound and a nickel-containing metal composite compound are mixed to obtain a mixture, the mixture is calcined to obtain a fired product, and the fired product is washed. It has a post-processing process containing the thing, and a post-processing process further includes coating the said washing | cleaning material with a coating material. The description about the mixing process, the baking process, and the washing process in this embodiment is the same as that in the said 1st Embodiment.

[Coating process]

A coating layer can be formed on the surface of the secondary particle of a lithium nickel composite oxide by mixing a coating material raw material and a lithium nickel composite oxide, and heat-processing as needed.

As the coating material, oxides, hydroxides, carbonates, nitrates, sulfates, halides, oxalates or alkoxides of at least one element selected from the group consisting of aluminum, boron, titanium, zirconium and tungsten can be used. It is preferable. The coating material is, for example, aluminum oxide, aluminum hydroxide, aluminum sulfate, aluminum chloride, aluminum alkoxide, boron oxide, boric acid, titanium oxide, titanium chloride, titanium alkoxide, zirconium oxide, zirconium chloride, tungsten oxide, tungstic acid, or the like. Can be mentioned. As a coating raw material, aluminum oxide, aluminum hydroxide, boron oxide, boric acid, titanium oxide, zirconium oxide, and tungsten oxide are preferable.

In order for the coating material to be coated on the surface of the lithium nickel composite oxide more efficiently, the coating material is preferably finer than the secondary particles of the lithium nickel composite oxide. Specifically, the average secondary particle diameter of the lithium nickel composite oxide is preferably 1 to 30 µm, and more preferably 3 to 20 µm. It is preferable that it is 1 micrometer or less, and, as for the average secondary particle diameter of a coating material raw material, it is more preferable that it is 0.1 micrometer or less. The smaller the lower limit of the average secondary particle size of the coating material is preferable, for example, but is 0.001 µm.

The average secondary particle diameter of a lithium nickel composite oxide can be measured using a laser diffraction scattering particle size distribution measuring device. Specifically, using a laser diffraction particle size distribution analyzer (Horiba, Ltd., model number: LA-950), 0.1 g of lithium nickel composite oxide was added to 50 ml of 0.2 mass% sodium hexamethaphosphate aqueous solution, and the lithium nickel composite The dispersion liquid which disperse | distributed oxide is obtained. Particle size distribution is measured about the obtained dispersion liquid, and a cumulative particle size distribution curve on a volume basis is obtained. In the obtained cumulative particle size distribution curve, the value of the particle diameter (D50) seen from the microparticle side at the time of 50% accumulation is made into the average secondary particle diameter of a lithium nickel composite oxide.

The average secondary particle diameter of the coating material is also measured in the same order.

The mixing of the coating material and the lithium nickel composite oxide may be performed in the same manner as the mixing at the time of producing the lithium nickel composite oxide. The method of mixing using the mixing apparatus which does not have strong grinding | pulverization without providing mixing media, such as a method of mixing using the powder mixer which has a stirring blade inside, is preferable. In addition, the coating layer can be more firmly adhered to the surface of the lithium nickel composite oxide by maintaining in an atmosphere containing water after mixing.

It is preferable that it is 0.01-10 mass% with respect to the gross mass of a coating material raw material and a lithium nickel composite oxide, and, as for the ratio of the coating material raw material at the time of mixing of a coating material raw material and a lithium nickel composite oxide, it is more preferable that it is 0.1-5 mass%. desirable.

The heat treatment conditions (temperature, holding time) in the heat processing performed as needed after mixing of a coating material raw material and a lithium nickel composite oxide may differ according to the kind of coating material raw material. It is preferable to set heat processing temperature in the range of 300-850 degreeC, and it is preferable that it is the temperature below the baking temperature of the said lithium nickel complex oxide. If the temperature is higher than the lithium nickel composite oxide sintering temperature, the coating material may be dissolved with the lithium nickel composite oxide so that a coating layer may not be formed. It is preferable to set the holding time in heat processing shorter than the holding time at the time of baking. As an atmosphere in heat processing, the same atmospheric gas as the said baking is mentioned.

Moreover, impurities can be reduced by performing heat processing on said conditions.

By using a method such as sputtering, CVD or vapor deposition, a coating layer may be formed on the surface of the lithium nickel composite oxide to obtain a positive electrode active material for a lithium secondary battery.

Moreover, the positive electrode active material for lithium secondary batteries may be obtained by mixing and baking the said lithium nickel composite oxide, a lithium compound, and a coating material raw material.

In addition, in this specification, the coating layer does not need to cover the whole surface of a lithium nickel complex oxide, and should just cover at least 30% or more.

By performing the coating process mentioned above, a coating material raw material and the lithium compound which exists in the surface of a lithium nickel composite oxide can react by heat processing, and a coating layer can be formed in the surface of a lithium nickel composite oxide. When the temperature of heat processing is 800 degreeC or more, the lithium atom in the particle | grains of a lithium nickel complex oxide diffuses into a coating layer, and the coating layer containing a coating material raw material and lithium may be formed in the surface of a lithium nickel composite oxide.

In a post-treatment step having a cleaning step and a coating step, impurities can be sufficiently removed by performing the cleaning step and the coating step under the above conditions, and further, it is possible to suppress the elution of lithium in the slurry in the cleaning step. . As a result, a lithium nickel composite oxide having a high output at a high current rate at a high voltage can be obtained.

`` Sixth Embodiment ''

This embodiment has a coating | coating process further after a drying process in the post-processing process of said 2nd Embodiment. That is, the manufacturing method of the lithium nickel composite oxide of 6th Embodiment has a mixing process, a baking process, and a post-processing process (washing process, a drying process, and a coating process) in this order. In other words, in the method for producing a lithium nickel composite oxide of the present embodiment, a lithium compound and a nickel-containing metal composite compound are mixed to obtain a mixture, the mixture is calcined to obtain a fired product, and the fired product is washed. It has a post-processing process containing the thing, and a post-processing process further includes drying the said washing | cleaning thing, and covering the said dry matter with coating material. The description about the mixing process, the baking process, the washing process, the drying process, and the coating process in this embodiment is the same as the description in the said embodiment.

In the post-treatment step of the fourth embodiment and the sixth embodiment, the sum of the residual sulfuric acid root and the residual lithium carbonate of the lithium nickel composite oxide obtained after the drying step is 0.6% by mass or less with respect to the total mass of the lithium nickel composite oxide, Moreover, it is the process of processing so that sodium may be 50 ppm or less with respect to the gross mass of a lithium nickel complex oxide.

In this invention, said 2nd Embodiment-6th Embodiment is preferable, 4th-6th Embodiment is more preferable, 4th Embodiment or 6th Embodiment is especially preferable.

<Lithium nickel composite oxide>

The lithium nickel composite oxide produced by the method for producing a lithium nickel composite oxide of the present invention is represented by general formula (I).

Li [Li _x (Ni _(1-yzw) Co _y Mn _z M _w ) _1-x ] O ₂ ... (I)

In formula (I), 0 <x <0.2, 0 <y <0.5, 0 <z <0.8, 0 <w <0.1, y + z + w <1, M is Fe, Cu, Ti, Mg, Al Or at least one metal selected from the group consisting of W, B, Mo, Nb, Zn, Sn, Zr, Ga and V.)

From a viewpoint of obtaining a lithium secondary battery with a higher initial coulomb efficiency, it is more preferable that x in general formula (I) is 0.005 or more, and it is especially preferable that it is 0.01 or more. From the viewpoint of obtaining a lithium secondary battery having a higher capacity retention rate, x in General Formula (I) is preferably 0.15 or less, more preferably 0.12 or less, and particularly preferably 0.09 or less. By setting x to the above range, a lithium secondary battery having a high initial coulombic efficiency and a high capacity retention can be obtained. When x becomes 0 or less, the capacity may fall.

The upper limit and lower limit of x can be arbitrarily combined. For example, it is preferable that x is 0.005 or more and 0.15 or less, It is more preferable that it is 0.01 or more and 0.12 or less, It is especially preferable that they are 0.01 or more and 0.09 or less.

In addition, from the viewpoint of obtaining a lithium secondary battery having high cycle characteristics, y in General Formula (I) is preferably 0.005 or more, more preferably 0.01 or more, and particularly preferably 0.05 or more. From the viewpoint of obtaining a lithium secondary battery having high thermal stability, y in General Formula (I) is preferably 0.4 or less, more preferably 0.35 or less, and particularly preferably 0.33 or less.

The upper limit and the lower limit of y can be arbitrarily combined. For example, it is preferable that they are 0.005 or more and 0.4 or less, It is more preferable that they are 0.01 or more and 0.35 or less, It is especially preferable that they are 0.05 or more and 0.33 or less.

From the viewpoint of obtaining a lithium secondary battery having high cycle characteristics, z in General Formula (I) is preferably 0.005 or more, more preferably 0.01 or more, and particularly preferably 0.015 or more. Moreover, from a viewpoint of obtaining the lithium secondary battery with high storage characteristic in high temperature (for example, in 60 degreeC environment), it is preferable that z in the said General formula (I) is 0.4 or less, It is more preferable that it is 0.38 or less, It is especially preferable that it is 0.35 or less.

The upper limit and lower limit of z can be arbitrarily combined. For example, z is preferably 0.005 or more and 0.4 or less, more preferably 0.01 or more and 0.38 or less, and particularly preferably 0.015 or more and 0.35 or less.

Moreover, it is preferable that w in the said General formula (I) exceeds 0, It is more preferable that it is 0.0005 or more, It is especially preferable that it is 0.001 or more. It is preferable that w in the said General formula (I) is 0.09 or less, It is more preferable that it is 0.08 or less, It is especially preferable that it is 0.07 or less.

The upper limit and lower limit of w can be arbitrarily combined. For example, it is preferable that w is more than 0 and is 0.09 or less, It is more preferable that it is 0.0005 or more and 0.08 or less, It is especially preferable that it is 0.001 or more and 0.07 or less.

In General Formula (I), it is preferable that y + z + w ≤ 0.3.

M in General Formula (I) represents at least one metal selected from the group consisting of Fe, Cu, Ti, Mg, Al, W, B, Mo, Nb, Zn, Sn, Zr, Ga and V. .

In addition, from the viewpoint of obtaining a lithium secondary battery having high cycle characteristics, M in General Formula (I) is preferably one or more selected from the group consisting of Ti, Mg, Al, W, B, and Zr, and thermally. It is preferable that it is 1 or more types chosen from the group which consists of Al, W, B, and Zr from a viewpoint of obtaining a highly stable lithium secondary battery.

The lithium nickel composite oxide produced by the method for producing a lithium nickel composite oxide of the present invention may have a coating layer.

The coating layer contains a compound of at least one element selected from the group consisting of aluminum, boron, titanium, zirconium and tungsten. The coating layer may contain a lithium compound. It is preferable that a coating layer is an aluminum compound, It is more preferable that it is lithium aluminate, It is still more preferable that it is lithium-aluminate.

In this embodiment, the coating layer may contain 1 or more types of metals chosen from the group which consists of Mn, Fe, Co, and Ni.

In the present embodiment, the composition of the coating layer can be confirmed by using STEM-EDX elemental line analysis, inductively coupled plasma emission analysis, electron beam microanalyzer analysis, or the like in the secondary particle cross section. Confirmation of the crystal structure of the coating layer can be performed using powder X-ray diffraction or electron beam diffraction.

(Layered structure)

The crystal structure of the lithium nickel composite oxide is a layered structure, more preferably a hexagonal crystal structure or a monoclinic crystal structure.

The hexagonal crystal structure is P3, P3 ₁ , P3 ₂ , R3, P-3, R-3, P312, P321, P3 ₁ 12, P3 ₁ 21, P3 ₂ 12, P3 ₂ 21, R32, P3m1, P31m , P3c1, P31c, R3m, R3c, P-31m, P-31c, P-3m1, P-3c1, R-3m, R-3c, P6, P6 ₁ , P6 ₅ , P6 ₂ , P6 ₄ , P6 ₃ , P-6, P6 / m, P6 ₃ / m, P622, P6 ₁ 22, P6 ₅ 22, P6 ₂ 22, P6 ₄ 22, P6 ₃ 22, P6mm, P6cc, P6 ₃ cm, P6 ₃ mc, P-6m2 , P-6c2, P-62m, P-62c, P6 / mmm, P6 / mcc, P6 ₃ / mcm, and P6 ₃ / mmc.

In addition, the monoclinic crystal structures include P2, P2 ₁ , C2, Pm, Pc, Cm, Cc, P2 / m, P2 ₁ / m, C2 / m, P2 / c, P2 ₁ / c, and C2 / c. It belongs to any one space group chosen from the group which consists of these.

Among them, from the viewpoint of obtaining a lithium secondary battery having a high discharge capacity, the crystal structure is particularly preferably a hexagonal crystal structure belonging to the space group R-3m or a monoclinic crystal structure belonging to C2 / m. .

The lithium compound used in the present invention can be used by mixing any one of lithium carbonate, lithium nitrate, lithium sulfate, lithium acetate, lithium hydroxide, lithium oxide, lithium chloride, and lithium fluoride or two or more thereof. In these, either or both of lithium hydroxide and lithium carbonate is preferable.

From the viewpoint of improving the handling properties of the positive electrode active material for lithium secondary batteries, the lithium carbonate component contained in the lithium nickel composite oxide is preferably 0.4 mass% or less, more preferably 0.39 mass% or less with respect to the total mass of the lithium nickel composite oxide. It is especially preferable that it is 0.38 mass% or less.

Moreover, it is preferable that the lithium hydroxide component contained in a lithium nickel complex oxide is 0.4 mass% or less with respect to the gross mass of a lithium nickel composite oxide, and it is 0.39 mass% or less from a viewpoint of improving the handling property of the positive electrode active material for lithium secondary batteries. It is preferable and it is especially preferable that it is 0.38 mass% or less.

The lithium carbonate component and the lithium hydroxide component contained in the lithium nickel composite oxide can be obtained by the neutralization titration method shown below.

<Determination of Lithium Carbonate in Lithium Nickel Composite Oxide (Neutralization Titration)>

20 g of lithium nickel composite oxide and 100 g of pure water are put in a 100 ml beaker and stirred for 5 minutes. After stirring, the lithium nickel composite oxide was filtered, 0.1 mol / L hydrochloric acid was added dropwise to 60 g of the remaining filtrate, and the pH of the filtrate was measured with a pH meter. A proper amount of hydrochloric acid at pH = 8.3 ± 0.1 is set to A ml, and an appropriate amount of hydrochloric acid at pH = 4.5 ± 0.1 is set to B ml, and the lithium carbonate concentration contained in the lithium nickel composite oxide is calculated from the following formula. . In the following formula, the molecular weight of lithium carbonate is Li in each atomic weight; 6.941, C; 12, O; It calculates as 16.

Lithium Carbonate Concentration (%) = 0.1 × (B-A) / 1000 × 73.882 / (20 × 60/100) × 100

Lithium hydroxide concentration (%) = 0.1 × (2A-B) / 1000 × 23.941 / (20 × 60/100) × 100

<Lithium secondary battery>

Next, while demonstrating the structure of a lithium secondary battery, the positive electrode which used the positive electrode active material for lithium secondary batteries using the lithium nickel composite oxide manufactured by the manufacturing method of the lithium nickel composite oxide of this invention as a positive electrode active material of a lithium secondary battery, and this A lithium secondary battery having a positive electrode will be described.

An example of the lithium secondary battery of this embodiment has a positive electrode and a negative electrode, the separator clamped between a positive electrode and a negative electrode, and the electrolyte solution arrange | positioned between a positive electrode and a negative electrode.

1A and 1B are schematic diagrams showing an example of the lithium secondary battery of the present embodiment. The cylindrical lithium secondary battery 10 of this embodiment is manufactured as follows.

First, as shown in FIG. 1A, a pair of separators 1 having a band shape, a band-shaped positive electrode 2 having a positive electrode lead 21 at one end, and a band shape having a negative electrode lead 31 at one end The negative electrode 3 is laminated in the order of the separator 1, the positive electrode 2, the separator 1, and the negative electrode 3, and wound to form the electrode group 4.

Subsequently, as shown in FIG. 1B, after the electrode group 4 and the insulator (not shown) are accommodated in the battery can 5, the bottom of the can is sealed, and the electrode group 4 is impregnated with the electrolyte solution 6. An electrolyte is disposed between the positive electrode 2 and the negative electrode 3. In addition, the lithium secondary battery 10 can be manufactured by sealing the upper part of the battery can 5 with the top insulator 7 and the sealing body 8.

As the shape of the electrode group 4, for example, a cross-sectional shape when the electrode group 4 is cut in the vertical direction with respect to the axis of the winding is a column having a circle, an ellipse, a rectangle, and a rounded rectangle. The shape of a phase is mentioned.

Moreover, as a shape of the lithium secondary battery which has such an electrode group 4, the shape prescribed | regulated by IEC60086 which is a standard with respect to the battery which the International Electrotechnical Commission (IEC) determined, or JIS C 8500 can be employ | adopted. For example, shapes, such as a cylinder and a square, are mentioned.

In addition, a lithium secondary battery is not limited to the said winding type structure, The laminated type structure which repeatedly laminated the laminated structure of a positive electrode, a separator, a negative electrode, and a separator may be sufficient. As a laminated lithium secondary battery, what is called a coin type battery, a button type battery, and a paper type (or sheet type) battery can be illustrated.

Hereinafter, each structure is demonstrated in order.

(Positive electrode)

The positive electrode of this embodiment can be manufactured by first preparing the positive electrode mixture containing a positive electrode active material, a electrically conductive material, and a binder, and supporting a positive electrode mixture on a positive electrode electrical power collector.

(Challenge)

As the conductive material of the positive electrode of the present embodiment, a carbon material can be used. Graphite powder, carbon black (for example, acetylene black), a fibrous carbon material, etc. are mentioned as a carbon material. Since carbon black is fine and has a large surface area, it is possible to increase the conductivity inside the positive electrode and improve the charge / discharge efficiency and the output characteristics by adding a small amount to the positive electrode mixture.However, when the carbon black is added too much, the positive electrode mixture by the binder and the positive electrode current collector Both the binding force and the binding force inside the positive electrode mixture are lowered, which causes the internal resistance to increase.

It is preferable that the ratio of the electrically conductive material in positive mix is 5 mass parts or more and 20 mass parts or less with respect to 100 mass parts of positive electrode active materials. When using fibrous carbon materials, such as graphitized carbon fiber and a carbon nanotube, as a electrically conductive material, this ratio can also be reduced.

(bookbinder)

Thermoplastic resin can be used as a binder which the positive electrode of this embodiment has.

Examples of the thermoplastic resin include polyvinylidene fluoride (hereinafter sometimes referred to as PVdF), polytetrafluoroethylene (hereinafter may be referred to as PTFE), ethylene tetrafluoride, propylene hexafluoropropylene, and vinylidene fluoride. Fluorine resins such as a den copolymer, a hexafluoropropylene-vinylidene fluoride copolymer, and an ethylene tetrafluoride-perfluorovinyl ether copolymer; Polyolefin resin, such as polyethylene and a polypropylene, is mentioned.

You may use these thermoplastic resins in mixture of 2 or more types. By using a fluorine resin and a polyolefin resin as a binder, the ratio of the fluorine resin to the whole positive electrode mixture is 1 mass% or more and 10 mass% or less, and the ratio of the polyolefin resin is 0.1 mass% or more and 2 mass% or less, It is possible to obtain a positive electrode mixture having both a high adhesive force and a high internal binding force.

(Positive electrode collector)

As a positive electrode electrical power collector which the positive electrode of this embodiment has, the strip | belt-shaped member which uses metal materials, such as Al, Ni, stainless steel as a forming material, can be used. Especially, it is preferable to make Al into a forming material and to process into a thin film form from the point which is easy to process and inexpensive.

As a method of carrying a positive electrode mixture on a positive electrode electrical power collector, the method of press-molding a positive electrode mixture on a positive electrode electrical power collector is mentioned. In addition, the cathode mixture may be pasted using an organic solvent, and the paste of the cathode mixture obtained may be applied to at least one surface side of the cathode current collector, dried, pressed and fixed to support the cathode mixture on the cathode current collector.

When pasteurizing a positive mix, as an organic solvent which can be used, Amine solvents, such as N, N- dimethylaminopropylamine and diethylene triamine; Ether solvents such as tetrahydrofuran; Ketone solvents such as methyl ethyl ketone; Ester solvents such as methyl acetate; Amide solvents such as dimethylacetamide and N-methyl-2-pyrrolidone (hereinafter may be referred to as NMP).

As a method of apply | coating the paste of positive mix to a positive electrode electrical power collector, the slit die coating method, the screen coating method, the curtain coating method, the knife coating method, the gravure coating method, and an electrostatic spray method are mentioned, for example.

By the method mentioned above, a positive electrode can be manufactured.

(Negative)

The negative electrode of the lithium secondary battery of this embodiment should be able to dope and dedope lithium ion at a potential lower than a positive electrode, and the electrode by which the negative electrode mixture containing a negative electrode active material is carried by the negative electrode electrical power collector, and a negative electrode active material alone The electrode which consists of these is mentioned.

(Negative Electrode Active Material)

As a negative electrode active material which a negative electrode has, a carbon material, a chalcogen compound (oxide, a sulfide, etc.), a nitride, a metal, or an alloy can mention the material which can dope and dedope lithium ion at a potential lower than a positive electrode.

As a carbon material which can be used as a negative electrode active material, graphite, such as natural graphite and artificial graphite, coke, carbon black, pyrolytic carbon, carbon fiber, and an organic high molecular compound sintered compact are mentioned.

Oxides usable as the negative electrode active material, SiO _2, SiO _x such as SiO formula of silicon oxide represented by (wherein, x is a positive real number); Oxides of titanium represented _{by the} formula TiO _x (here, x is a positive real number) such as TiO ₂ and TiO; Oxide of vanadium represented _{by the} formula VO _x (here, x is a positive real number) such as V ₂ O ₅ and VO ₂ ; Oxides of iron represented _{by the} formula FeO _x (where x is a positive real number) such as Fe ₃ O ₄ , Fe ₂ O ₃ , and FeO; An oxide of tin represented _{by the} formula SnO _x (here, x is a positive real number) such as SnO ₂ and SnO; Oxides of tungsten represented _{by the} general formula WO _x (where x is a positive real number) such as WO ₃ and WO ₂ ; And metal composite oxides containing lithium, such as Li ₄ Ti ₅ O ₁₂ and LiVO ₂ , and titanium or vanadium.

As a sulfide which can be used as a negative electrode active material, sulfides of titanium represented by a formula TiS _x (where x is a positive real number) such as Ti ₂ S ₃ , TiS ₂ , TiS; Sulfides of vanadium represented _{by the} formula VS _x (where x is a positive real number) such as V ₃ S ₄ , VS ₂ and VS; Sulfides of iron represented _{by the} formula FeS _x (where x is a positive real number) such as Fe ₃ S ₄ , FeS ₂ , and FeS; Sulfides of molybdenum represented _{by the} formula MoS _x (where x is a positive real number) such as Mo ₂ S ₃ and MoS ₂ ; Sulfides of tin represented _{by the} formula SnS _x (here, x is a positive real number) such as SnS ₂ and SnS; Sulfides of tungsten represented _{by the} formula WS _x (where x is a positive real number) such as WS ₂ ; Sulfide of antimony represented _{by the} formula SbS _x (where x is a positive real number) such as Sb ₂ S ₃ ; And sulfides of selenium represented _{by the} formula SeS _x (here, x is a positive real number) such as Se ₅ S ₃ , SeS ₂ , and SeS.

Nitride as usable as the negative electrode active _{material, Li 3 N, Li 3-} x A x N ( wherein, A is any one or both of Ni and Co, 0 a <x <3.) Include lithium-containing nitrides such as Can be.

1 type of these carbon materials, oxides, sulfides, and nitrides may be used, or may be used in combination of 2 or more type. In addition, these carbon materials, oxides, sulfides, and nitrides may be either crystalline or amorphous.

Moreover, lithium metal, a silicon metal, a tin metal, etc. are mentioned as a metal which can be used as a negative electrode active material.

As an alloy which can be used as a negative electrode active material, Li alloy, such as Li-Al, Li-Ni, Li-Si, Li-Sn, Li-Sn-Ni; Silicon alloys such as Si-Zn; Tin alloys such as Sn-Mn, Sn-Co, Sn-Ni, Sn-Cu, Sn-La; It may also include alloys such as _{Cu 2 Sb, La 3 Ni 2} Sn 7.

These metals and alloys are mainly used alone as electrodes after being processed into thin films, for example.

In the negative electrode active material, the potential of the negative electrode hardly changes from the uncharged state to the fully charged state at the time of charging (good dislocation flatness), and the capacity retention rate at the time of repeated charge / discharge with low average discharge potential ( The carbon material which has graphite as a main component, such as natural graphite and artificial graphite, is used preferably for such reasons. The shape of the carbon material may be, for example, flaky like natural graphite, spherical like mesocarbon microbeads, fibrous like graphitized carbon fibers, or aggregates of fine powder.

The said negative electrode mixture may contain a binder as needed. Examples of the binder include thermoplastic resins, and specific examples include PVdF, thermoplastic polyimide, carboxymethyl cellulose, polyethylene, and polypropylene.

(Negative current collector)

As a negative electrode electrical power collector which a negative electrode has, the strip | belt-shaped member which uses metal materials, such as Cu, Ni, stainless steel, as a forming material, is mentioned. Especially, since it is difficult to make an alloy with lithium and it is easy to process, it is preferable to use Cu as a forming material and to process into thin film form.

As a method of supporting the negative electrode mixture on such a negative electrode current collector, as in the case of the positive electrode, a method of forming a paste using a method by pressure molding, a solvent, or the like, coating on a negative electrode current collector, pressing after drying and pressing Can be mentioned.

(Separator)

As a separator which the lithium secondary battery of this embodiment has, for example, it has a form of a porous membrane, a nonwoven fabric, a woven fabric, etc. which consist of materials, such as polyolefin resin, such as polyethylene and a polypropylene, a fluororesin, and a nitrogen-containing aromatic polymer. Material can be used. Moreover, you may form a separator using these materials 2 or more types, and you may laminate | stack these materials and form a separator.

In the present embodiment, the separator has a permeation resistance of 50 seconds / 100 cc or more, 300 seconds /, in accordance with the Gurley method defined in JIS P 8117, in order to allow the electrolyte to permeate well during battery use (at charge and discharge). It is preferable that it is 100 cc or less, and it is more preferable that it is 50 second / 100 cc or more and 200 second / 100 cc or less.

Moreover, the porosity of a separator becomes like this. Preferably it is 30 volume% or more and 80 volume% or less with respect to the volume of a separator, More preferably, it is 40 volume% or more and 70 volume% or less. The separator may be a laminate of separators having different porosities.

(Electrolyte amount)

The electrolyte solution which the lithium secondary battery of this embodiment has contains an electrolyte and an organic solvent.

Examples of the electrolyte included in the electrolyte include LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN ( SO ₂ CF ₃ ) (COCF ₃ ), Li (C ₄ F ₉ SO ₃ ), LiC (SO ₂ CF ₃ ) ₃ , Li ₂ B ₁₀ Cl ₁₀ , LiBOB (where BOB is bis (oxalato) borate. ), LiFSI (where FSI is bis (fluorosulfonyl) imide), lower aliphatic lithium carboxylate salt, LiAlCl ₄ and the like, and lithium compounds such as these may be used. Among them, the electrolyte is selected from the group consisting of fluorine-containing LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ and LiC (SO ₂ CF ₃ ) ₃ . It is preferable to use what contains at least 1 type.

Moreover, as an organic solvent contained in the said electrolyte solution, For example, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-trifluoromethyl- 1, 3- dioxolan-2-one, 1 Carbonates, such as a 2-di (methoxycarbonyloxy) ethane; 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropylmethylether, 2,2,3,3-tetrafluoropropyldifluoromethylether, tetrahydrofuran, 2-methyltetrahydro Ethers such as furan; Esters such as methyl formate, methyl acetate and γ-butyrolactone; Nitriles such as acetonitrile and butyronitrile; Amides such as N, N-dimethylformamide and N, N-dimethylacetamide; Carbamates such as 3-methyl-2-oxazolidone; Sulfur-containing compounds such as sulfolane, dimethyl sulfoxide, 1,3-propanesultone, or those in which fluoro groups are further introduced into these organic solvents (substitute one or more of the hydrogen atoms of the organic solvent with fluorine atoms) can be used. Can be.

As an organic solvent, it is preferable to mix and use 2 or more types of these. Especially, the mixed solvent containing carbonates is preferable, The mixed solvent of cyclic carbonate and acyclic carbonate, and the mixed solvent of cyclic carbonate and ether are more preferable. As a mixed solvent of a cyclic carbonate and an acyclic carbonate, the mixed solvent containing ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate is preferable. The electrolytic solution using such a mixed solvent has a wide operating temperature range, hardly deteriorates even when charging and discharging at a high current rate, hardly deteriorates even after long use, and graphite such as natural graphite and artificial graphite as an active material of a negative electrode. Even when the material is used, it has many features of being hardly decomposable.

The electrolyte is, due to high safety of the lithium secondary battery is obtained, it is preferable to use an electrolytic solution comprising an organic solvent having a lithium compound and a fluorine substituent containing fluorine such as LiPF _6. A mixed solvent containing ethers having a fluorine substituent, such as pentafluoropropylmethyl ether, 2,2,3,3-tetrafluoropropyldifluoromethyl ether and dimethyl carbonate, is charged and discharged at a high current rate. Even if it carries out, since a capacity retention is high, it is more preferable.

You may use a solid electrolyte instead of said electrolyte solution. As a solid electrolyte, organic type polymer electrolytes, such as a high molecular compound containing at least 1 sort (s) of a polyethylene oxide type high molecular compound, a polyorganosiloxane chain, or a polyoxyalkylene chain, can be used, for example. Moreover, what is called a gel type thing which hold | maintained the nonaqueous electrolyte solution to a high molecular compound can also be used. In addition, Li ₂ S-SiS ₂ , Li ₂ S-GeS ₂ , Li ₂ SP ₂ S ₅ , Li ₂ SB ₂ S ₃ , Li ₂ S-SiS ₂ -Li ₃ PO ₄ , Li ₂ S-SiS ₂ -Li ₂ And inorganic solid electrolytes containing sulfides such as SO ₄ and Li ₂ S-GeS ₂ -P ₂ S ₅ , and mixtures of two or more thereof may be used. By using these solid electrolytes, the safety of a lithium secondary battery may be improved more.

Moreover, in the lithium secondary battery of this embodiment, when using a solid electrolyte, a solid electrolyte may play the role of a separator, and in that case, a separator may not be needed.

Since the lithium metal composite oxide of this embodiment mentioned above uses the positive electrode active material of the above structures, the life of the lithium secondary battery using a positive electrode active material can be extended.

Moreover, since the positive electrode of the above structure has the positive electrode active material for lithium secondary batteries of this embodiment mentioned above, the lifetime of a lithium secondary battery can be extended.

Moreover, since the lithium secondary battery of the above structure has the positive electrode mentioned above, it becomes a lithium secondary battery with a long life compared with the former.

EXAMPLE

Next, the present invention will be described in more detail with reference to Examples.

In the present Example, evaluation of the positive electrode active material for lithium secondary batteries, the production evaluation of the positive electrode for lithium secondary batteries, and the lithium secondary battery was performed as follows.

(1) Evaluation of Positive Electrode Active Material for Lithium Secondary Battery

1 Composition Analysis of Lithium Nickel Composite Oxide, Determination of Residual Sulfate and Residual Lithium Sulfate in Li-nickel Composite Oxide

The composition analysis of the lithium nickel composite oxide produced by the method described below and the measurement of the residual sulfate and residual lithium sulfate present in the lithium nickel composite oxide were performed by inductively coupled plasma emission after dissolving the powder of the lithium nickel composite oxide obtained in hydrochloric acid. It carried out using the analyzer (SPS3000 by SAI Nano Technology Co., Ltd.).

2 Determination of Metal Elements in Lithium Nickel Composite Oxides

The inductively coupled plasma luminescence analysis device (SPS3000, manufactured by SAI Nano Technology Co., Ltd.) was used to analyze by inductively coupled plasma luminescence analysis.

(2) Production of positive electrode for lithium secondary battery

The positive electrode active material for a lithium secondary battery, the electrically conductive material (acetylene black), and the binder (PVdF) obtained by the manufacturing method mentioned later are added so that it may become a composition of the positive electrode active material for a lithium secondary battery: conductive material: binder = 92: 5: 3 (mass ratio), and By kneading, a paste-like positive electrode mixture was prepared. In preparing the positive mix, N-methyl-2-pyrrolidone was used as an organic solvent.

The obtained positive electrode mixture was applied to an Al foil having a thickness of 15 μm to be a current collector, and vacuum dried at 60 ° C. for 3 hours to obtain a positive electrode for a lithium secondary battery. The electrode area of this positive electrode for lithium secondary batteries was 1.65 cm <2>.

(3) Preparation of a lithium secondary battery (coin type half cell)

The following operation was performed in the glove box of dry air atmosphere.

The positive electrode for lithium secondary batteries produced in "(2) Production of positive electrode for lithium secondary batteries" was placed on the underside of the parts (manufactured by Hosen Corporation) for coin-type battery R2032 with the aluminum foil face downward, and the laminated film separator thereon. (The porous heat-resistant porous layer was laminated (thickness 16 micrometers) on the polyethylene porous film). 300 µl of the electrolyte was injected therein. The electrolyte is ethylene carbonate (hereinafter sometimes referred to as EC), dimethyl carbonate (hereinafter sometimes referred to as DMC), and ethyl methyl carbonate (hereinafter sometimes referred to as EMC). 35 (volume ratio) mixed solution, (may be shown as follows, LiPF ₆ / EC + DMC + EMC.) the LiPF ₆ was dissolved to be a 1.0 mol / ℓ was used.

Next, metal lithium is used as the negative electrode, the negative electrode is placed on the upper side of the laminated film separator, the top cover is covered via a gasket, and the coking is caulked with a lithium secondary battery (coin-type half cell R2032. May be referred to as.

(4) discharge capacity

The charge / discharge test was performed on the conditions shown below using the half cell produced by "(3) manufacture of a lithium secondary battery (coin type half cell)."

<Discharge test>

<The production of a lithium secondary battery (coin type half cell)> The discharge rate test was done on the conditions shown below using the half cell produced by. The 3 CA discharge capacity retention rate in the discharge rate test was calculated as follows.

<Discharge rate test>

Test temperature 25 ℃

Maximum charging voltage 4.45 V, charging time 8 hours, charging current 0.2 CA constant current constant voltage charging

Discharge voltage 2.5 V, constant current discharge

By calculating the discharge capacity when the constant current was discharged at 0.2 CA and the discharge capacity when the battery was discharged at 3 CA, the 3 CA discharge capacity retention rate obtained by the following equation was obtained. The higher the 3 CA discharge capacity retention rate, the higher the output power.

<3CA discharge capacity retention rate>

3 CA discharge capacity retention rate (%)

= (Discharge capacity in 3 CA / discharge capacity in 0.2 CA) × 100

(Example 1)

[Mixing process]

1. Preparation of lithium nickel composite oxide 1

As the nickel-containing metal composite compound, fine nickel cobalt manganese aluminum metal composite hydroxide 1 (Ni _0.875 Co _0.095 Mn _0.02 Al _0.01 (OH) ₂ ) was produced by a continuous coprecipitation method. The obtained nickel cobalt manganese aluminum metal composite hydroxide 1 was heated up to 650 degreeC at the temperature increase rate of 100 degreeC / hour in dry air atmosphere using the electric furnace, and was kept at 650 degreeC for 5 hours. Then, it cooled to room temperature and obtained nickel cobalt manganese aluminum metal composite oxide 1.

The nickel cobalt manganese aluminum metal composite oxide 1 and the lithium hydroxide powder were weighed and mixed so that Li / (Ni + Co + Mn + Al) = 1.10 (molar ratio).

[Firing process]

Then, it baked at 760 degreeC for 5 hours in oxygen atmosphere, and obtained the fired material 1.

[Post-processing process]

Then, the post-processing process which has the following washing | cleaning process, a drying process, and a coating process was implemented.

Cleaning process

The calcined material 1 was washed with 11 mass times water with respect to the mass of the calcined material 1.

Drying process

Then, the baked 1 was dried at 150 degreeC for 12 hours, and the washing | cleaning dry powder 1 was obtained.

· Coating process

The dry cleaning powder 1 and aluminum oxide (Alumina C by Nihon Aerosil Co., Ltd., average 13 nm of average particle diameter) were dry-mixed with the mixer, and the mixed powder was obtained. At this time, Al of aluminum oxide was 0.015 mol with respect to 1 mol of total contents of Ni, Co, Mn, and Al of washing | cleaning dry powder 1. That is, the ratio of the atomic ratio of Al of aluminum oxide to the sum of atomic ratios of Ni, Co, Mn and Al in the washing and drying powder 1 was 1.5 mol%. The obtained powder was calcined at 760 ° C. for 10 hours in an oxygen atmosphere to obtain lithium nickel composite oxide 1.

2. Evaluation of washing dry powder 1 and lithium nickel composite oxide 1

The composition analysis of the washing and drying powder 1 was performed, and when it responded to General formula (1), it was x = 0.006, y = 0.093, z = 0.020, w = 0.009.

The composition analysis of lithium nickel complex oxide 1 was performed, and it responded to General formula (1), and x = 0.001, y = 0.093, z = 0.020, w = 0.022.

The 3CA discharge capacity retention rate at 4.45 V of the lithium nickel composite oxide 1 was 85.4%.

(Example 2)

[Mixing process]

1. Preparation of lithium nickel composite oxide 2

As the nickel-containing metal composite compound, fine nickel cobalt manganese aluminum metal composite hydroxide 2 (Ni _0.875 Co _0.095 Mn _0.02 Al _0.01 (OH) ₂ ) was produced by a continuous coprecipitation method. The obtained nickel cobalt manganese aluminum metal composite hydroxide 2 was heated up to 650 degreeC at the temperature increase rate of 100 degreeC / hour in dry air atmosphere using the electric furnace, and was hold | maintained at 650 degreeC for 5 hours. Thereafter, the mixture was allowed to cool to room temperature to obtain nickel cobalt manganese aluminum metal composite oxide 2.

Nickel cobalt manganese aluminum metal composite oxide 2 and lithium hydroxide powder were weighed and mixed so that Li / (Ni + Co + Mn + Al) = 1.10 (molar ratio).

[Firing process]

Then, it baked at 760 degreeC for 5 hours in oxygen atmosphere, and obtained the baked material 2.

[Post-processing process]

Then, the post-processing process which has the following washing | cleaning process, a drying process, and a recalcination process was implemented.

Cleaning process

The baked 2 was washed with 11 mass times water with respect to the mass of the baked 2.

Drying process

Then, the baked 2 was dried at 150 degreeC for 12 hours, and the washing and drying powder 2 was obtained.

Recycling process

Thereafter, the washed and dried powder 2 was calcined at 760 ° C. for 10 hours in an oxygen atmosphere to obtain a lithium nickel composite oxide 2.

2. Evaluation of washing dry powder 2 and lithium nickel composite oxide 2

The composition analysis of the washing and drying powder 2 was performed, and when it responded to General formula (1), it was x = 0.007, y = 0.093, z = 0.020, w = 0.009.

The composition analysis of lithium nickel complex oxide 2 was performed, and it responded to General formula (1), and x = 0.007, y = 0.094, z = 0.020, w = 0.009.

The 3CA discharge capacity retention rate at 4.45 V of the lithium nickel composite oxide 2 was 76.4%.

(Example 3)

[Mixing process]

1. Preparation of lithium nickel composite oxide 3

As the nickel-containing metal composite compound, fine nickel cobalt manganese aluminum metal composite hydroxide 3 (Ni _0.875 Co _0.095 Mn _0.02 Al _0.01 (OH) ₂ ) was produced by a continuous coprecipitation method. The obtained nickel cobalt manganese aluminum metal composite hydroxide 3 was heated up to 650 degreeC at the temperature increase rate of 100 degreeC / hour in dry air atmosphere using the electric furnace, and was kept at 650 degreeC for 5 hours. Thereafter, the mixture was allowed to cool to room temperature to obtain nickel cobalt manganese aluminum metal composite oxide 3.

Nickel cobalt manganese aluminum metal composite oxide 3 and lithium hydroxide powder were weighed and mixed such that Li / (Ni + Co + Mn + Al) = 1.15 (molar ratio).

[Firing process]

Then, it baked at 720 degreeC in oxygen atmosphere for 10 hours, and obtained the baked 3.

[Post-processing process]

Then, the post-processing process which has the following washing | cleaning process, a drying process, and a coating process was implemented.

Cleaning process

The baked 3 was washed with 12 mass times water with respect to the mass of the baked 3.

Drying process

Then, the baked 3 was dried at 150 degreeC for 12 hours, and the washing and drying powder 3 was obtained.

· Coating process

The dry cleaning powder 3 and aluminum oxide (Alumina C by Nihon Aerosil Co., Ltd., average 13 nm of average particle diameter) were dry-mixed with the mixer, and the mixed powder was obtained. Al of aluminum oxide was 0.015 mol with respect to 1 mol of total contents of Ni, Co, Mn, and Al of washing | cleaning dry powder 3. That is, the ratio of the atomic ratio of Al of aluminum oxide to the sum of atomic ratios of Ni, Co, Mn and Al in the washing and drying powder 3 was 1.5 mol%. The obtained powder was baked at 760 degreeC for 10 hours in oxygen atmosphere, and lithium nickel composite oxide 3 was obtained.

2. Evaluation of washing dry powder 3 and lithium nickel composite oxide 3

The composition analysis of the washing and drying powder 3 was performed, and when it responded to General formula (1), it was x = 0.030, y = 0.094, z = 0.020, w = 0.009.

The composition analysis of lithium nickel complex oxide 3 was performed, and it responded to General formula (1), and x = 0.019, y = 0.092, z = 0.020, w = 0.024.

The 3CA discharge capacity retention rate at 4.45 V of the lithium nickel composite oxide 3 was 78.9%.

(Comparative Example 1)

[Mixing process]

1. Preparation of lithium nickel composite oxide 4

As the nickel-containing metal composite compound, fine nickel cobalt manganese aluminum metal composite hydroxide 4 (Ni _0.875 Co _0.095 Mn _0.02 Al _0.01 (OH) ₂ ) was produced by a continuous coprecipitation method. The obtained nickel cobalt manganese aluminum metal composite hydroxide 4 was heated up to 650 degreeC at the temperature increase rate of 100 degreeC / hour in dry air atmosphere using the electric furnace, and was kept at 650 degreeC for 5 hours. Thereafter, the mixture was allowed to cool to room temperature to obtain nickel cobalt manganese aluminum metal composite oxide 4.

The nickel cobalt manganese aluminum metal composite oxide 4 and the lithium hydroxide powder were weighed and mixed such that Li / (Ni + Co + Mn + Al) = 1.12 (molar ratio).

[Firing process]

Then, it baked at 760 degreeC for 5 hours in oxygen atmosphere, and obtained the baked 4.

[Plastic process]

Thereafter, the calcined product 4 was calcined at 760 ° C. for 10 hours in an oxygen atmosphere to obtain a lithium nickel composite oxide 4.

2. Evaluation of lithium nickel composite oxide 4

The composition analysis of lithium nickel complex oxide 4 was performed, and it responded to General formula (1), and x = -0.002, y = 0.095, z = 0.020, w = 0.010.

The 3CA discharge capacity retention rate at 4.45 V of the lithium nickel composite oxide 4 was 63.9%.

(Comparative Example 2)

[Mixing process]

1. Preparation of lithium nickel composite oxide 5

As the nickel-containing metal composite compound, fine nickel cobalt manganese aluminum metal composite hydroxide 5 (Ni _0.855 Co _0.095 Mn _0.02 Al _0.03 (OH) ₂ ) was produced by a continuous coprecipitation method. The obtained nickel cobalt manganese aluminum metal composite hydroxide 5 was heated up to 650 degreeC at the temperature increase rate of 100 degreeC / hour in dry air atmosphere using the electric furnace, and was kept at 650 degreeC for 5 hours. Thereafter, the mixture was allowed to cool to room temperature to obtain nickel cobalt manganese aluminum metal composite oxide 5.

The nickel cobalt manganese aluminum metal composite oxide 5 and the lithium hydroxide powder were weighed and mixed so that Li / (Ni + Co + Mn + Al) = 1.05 (molar ratio).

[Firing process]

Then, it baked at 770 degreeC in oxygen atmosphere for 5 hours, and obtained the baked material 5.

[Coating process]

The calcined product 5 and aluminum oxide (Alumina C manufactured by Nippon Aerosol Co., Ltd., average primary particle diameter of 13 nm) were dry mixed with a mixer to obtain a mixed powder. Al of aluminum oxide was 0.020 mol with respect to 1 mol of total content of Ni, Co, Mn, and Al of the baking product 5. That is, the ratio of the atomic ratio of Al of aluminum oxide to the sum of the atomic ratios of Ni, Co, Mn and Al in the calcined product 5 was 2.0 mol%. Thereafter, the mixer atmosphere was controlled at 50 ° C and 100% relative humidity, and left to stand for 1 hour. The obtained powder was baked at 770 degreeC for 5 hours in oxygen atmosphere, and lithium nickel composite oxide 5 was obtained.

2. Evaluation of lithium nickel composite oxide 5

The composition analysis of lithium nickel complex oxide 5 was performed, and it responded to General formula (1), and x = 0.003, y = 0.092, z = 0.020, w = 0.047.

The 3CA discharge capacity retention rate at 4.45 V of the lithium nickel composite oxide 5 was 65.1%.

(Comparative Example 3)

[Mixing process]

1. Preparation of lithium nickel composite oxide 6

As a nickel-containing metal composite compound, fine nickel cobalt manganese aluminum metal composite hydroxide 6 (Ni _0.875 Co _0.095 Mn _0.02 Al _0.01 (OH) ₂ ) was produced by a continuous coprecipitation method. The obtained nickel cobalt manganese aluminum metal composite hydroxide 6 was heated up to 650 degreeC at the temperature increase rate of 100 degreeC / hour in dry air atmosphere using the electric furnace, and was kept at 650 degreeC for 5 hours. Then, it cooled to room temperature and obtained nickel cobalt manganese aluminum metal composite oxide 6.

Nickel cobalt manganese aluminum metal composite oxide 6 and lithium hydroxide powder were weighed to have Li / (Ni + Co + Mn + Al) = 1.10 (molar ratio), and tungsten oxide pulverized with a jet mill was weighed and mixed. W of tungsten oxide was 0.004 mol with respect to 1 mol of total contents of Ni, Co, Mn, and Al of lithium nickel composite oxide 6. That is, the ratio of the atomic ratio of W of tungsten oxide to the sum of the atomic ratios of Ni, Co, Mn and Al in the lithium nickel composite oxide 6 was 0.4 mol%.

[Firing process]

Then, it baked at 760 degreeC for 5 hours in oxygen atmosphere, and obtained the fired material 6.

[Post-processing process]

Then, the post-processing process which has the following washing | cleaning process, a drying process, and a coating process was implemented.

Cleaning process

The baked 6 was washed with 12 mass times water with respect to the mass of the baked 6.

Drying process

Then, the baked 6 was dried at 150 degreeC for 12 hours, and the washing and drying powder 6 was obtained.

· Coating process

The dry cleaning powder 6 and aluminum oxide (Alumina C by Nihon Aerosil Co., Ltd., average 13 nm of average particle diameter) were dry-mixed with the mixer, and the mixed powder was obtained. Al of aluminum oxide was 0.015 mol with respect to 1 mol of total contents of Ni, Co, Mn, and Al of washing | cleaning dry powder 6. That is, the ratio of the atomic ratio of Al of aluminum oxide to the sum of atomic ratios of Ni, Co, Mn and Al in the washing and drying powder 6 was 1.5 mol%. The obtained powder was calcined at 760 ° C. for 10 hours in an oxygen atmosphere to obtain lithium nickel composite oxide 6.

2. Evaluation of washing dry powder 6 and lithium nickel composite oxide 6

The composition analysis of the washing and drying powder 6 was performed, and when it responded to General formula (1), it was x = -0.008, y = 0.093, z = 0.021, w = 0.009.

The composition analysis of lithium nickel complex oxide 6 was performed, and it responded to General formula (1), and x = -0.16, y = 0.093, z = 0.021, w = 0.023.

The 3CA discharge capacity retention rate at 4.45 V of the lithium nickel composite oxide 6 was 64.7%.

(Comparative Example 4)

[Mixing process]

1. Preparation of lithium nickel composite oxide 7

As the nickel-containing metal composite compound, fine nickel cobalt manganese aluminum metal composite hydroxide 7 (Ni _0.875 Co _0.095 Mn _0.02 Al _0.01 (OH) ₂ ) was produced by a continuous coprecipitation method. The obtained nickel cobalt manganese aluminum metal composite hydroxide 7 was heated up to 650 degreeC at the temperature increase rate of 100 degreeC / hour in dry air atmosphere using the electric furnace, and was hold | maintained at 650 degreeC for 5 hours. Thereafter, the mixture was allowed to cool to room temperature to obtain nickel cobalt manganese aluminum metal composite oxide 7.

Nickel cobalt manganese aluminum metal composite oxide 7 and lithium hydroxide powder were weighed to have Li / (Ni + Co + Mn + Al) = 1.10 (molar ratio), and tungsten oxide ground by a jet mill was weighed and mixed. W of tungsten oxide was 0.004 mol with respect to 1 mol of total content of Ni, Co, Mn, and Al in lithium nickel complex oxide 7. That is, the ratio of the atomic ratio of W of tungsten oxide to the sum of the atomic ratios of Ni, Co, Mn and Al in the lithium nickel composite oxide 7 was 0.4 mol%.

[Firing process]

Then, it baked at 760 degreeC for 5 hours in oxygen atmosphere, and obtained the fired material 7.

[Post-processing process]

Then, the post-processing process which has the following washing | cleaning process, a drying process, and a coating process was implemented.

Cleaning process

The calcined product 7 was washed with water of 22 mass times relative to the calcined product 7.

Drying process

Thereafter, the calcined product 7 was dried at 150 ° C. for 12 hours to obtain a washing and drying powder 7.

· Coating process

The calcined product 7 and aluminum oxide (Alumina C manufactured by Nippon Aerosol Co., Ltd., average primary particle size 13 nm) were dry mixed with a mixer to obtain a mixed powder. Al of aluminum oxide was 0.015 mol with respect to 1 mol of total contents of Ni, Co, Mn, and Al of washing | cleaning dry powder 7. That is, the ratio of the atomic ratio of Al of aluminum oxide to the sum of the atomic ratios of Ni, Co, Mn and Al in the washing and drying powder 7 was 1.5 mol%. The obtained powder was baked at 760 degreeC for 10 hours in oxygen atmosphere, and lithium nickel complex oxide 7 was obtained.

2. Evaluation of washing dry powder 7 and lithium nickel composite oxide 7

The composition analysis of the washing and drying powder 7 was carried out, and it was x = -0.011, y = 0.094, z = 0.021, w = 0.009 as a result of responding to General formula (1).

The composition analysis of lithium nickel complex oxide 7 was performed, and it responded to General formula (1), and it was x = -0.019, y = 0.093, z = 0.021, w = 0.024.

The 3CA discharge capacity retention rate at 4.45 V of the lithium nickel composite oxide 7 was 68.4%.

The result of Examples 1-3 and Comparative Examples 1-4 is put together in Table 1, and is described. In Table 1 below, "Li / Me" is the molar ratio of lithium in the obtained lithium nickel composite oxide (molar ratio of lithium to the total amount of nickel, cobalt, manganese and aluminum). In the following Table 1, "after a drying process" means the analysis result of the washing dry powder after a drying process in the said post-processing process.

In the following Table 1, "after a plasticity or a coating process" means the result of having analyzed the said lithium nickel complex oxides 1-7.

As shown in Table 1, according to Examples 1 to 3 to which the present invention was applied, a lithium nickel composite oxide having a high output at a high current rate at a high voltage could be produced.

On the other hand, the lithium nickel composite oxide manufactured by Comparative Examples 1-4 which do not apply this invention had the low output in the high current rate at high voltage. Moreover, since the comparative examples 1-2 which did not perform the post-processing process including a washing process have many impurities, it is inferred that the output in the high current rate at high voltage fell. Although Comparative Examples 3-4 performed the post-processing process including a washing | cleaning process, since lithium eluted by over-cleaning, it is inferred that the output in the high current rate at high voltage fell.

Industrial availability

According to the present invention, a method for producing a lithium nickel composite oxide having a high output at a high current rate at a high voltage can be provided.

DESCRIPTION OF SYMBOLS 1 Separator, 2 positive electrode, 3 negative electrode, 4 electrode group, 5 battery can, 6 electrolyte solution, 7 top insulator, 8 sealing body, 10 lithium secondary battery, 21 positive electrode lead, 31 negative electrode lead

Claims (11)

As a manufacturing method of the lithium nickel composite oxide represented by the following general formula (I),
A mixing step of mixing the lithium compound and the nickel-containing metal composite compound to obtain a mixture,
A firing step of firing the mixture to obtain a fired product;
It has a post-processing process including the washing process of washing a baked material,
The said mixing process mixes so that the molar ratio (Li / Me) of lithium contained in the said lithium compound and the metal element in a nickel containing metal complex compound may become a ratio exceeding 1,
In the post-treatment step, the total amount of the residual sulfate sulfate and residual lithium carbonate in the lithium nickel composite oxide obtained after the post-treatment step is 0.3 mass% or less with respect to the total mass of the lithium nickel composite oxide, and the content of sodium is lithium nickel. A process for producing a lithium nickel composite oxide, comprising the step of treating it to be 50 ppm or less with respect to the total mass of the composite oxide.
Li [Li _x (Ni _(1-yzw) Co _y Mn _z M _w ) _1-x ] O ₂ ... (I)
In formula (I), 0 <x <0.2, 0 <y <0.5, 0 <z <0.8, 0 <w <0.1, y + z + w <1, M is Fe, Cu, Ti, Mg, Al Or at least one metal selected from the group consisting of W, B, Mo, Nb, Zn, Sn, Zr, Ga and V.) The method of claim 1,
The method for producing a lithium nickel composite oxide of the general formula (I), wherein y + z + w ≤ 0.3. The method according to claim 1 or 2,
The said nickel baking process WHEREIN: The manufacturing method of the lithium nickel complex oxide whose baking temperature is 300 degreeC or more and 1000 degrees C or less. The method according to any one of claims 1 to 3,
The said post-treatment process WHEREIN: The manufacturing method of the lithium nickel complex oxide which includes the drying process which dries the obtained lithium nickel complex oxide after a washing | cleaning process. The method according to any one of claims 1 to 3,
The said post-treatment process WHEREIN: The manufacturing method of the lithium nickel complex oxide which includes the recalcination process which refires the obtained lithium nickel complex oxide after a washing | cleaning process. The method of claim 4, wherein
The said post-treatment process WHEREIN: The manufacturing method of the lithium nickel complex oxide which includes the recalcination process which refires the obtained lithium nickel complex oxide after a drying process. The method according to any one of claims 1 to 3,
In the post-treatment step, the lithium nickel composite oxide obtained after the washing step is mixed with a compound of at least one element selected from the group consisting of aluminum, boron, titanium, zirconium, and tungsten, and the surface of the lithium nickel composite oxide is A method for producing a lithium nickel composite oxide comprising a coating step of coating with an elemental compound. The method according to any one of claims 1 to 3,
In the post-treatment step, a method of producing a lithium nickel composite oxide comprising a coating step of mixing the lithium nickel composite oxide and the aluminum compound obtained after the washing step and coating the surface of the lithium nickel composite oxide with an aluminum compound. The method of claim 4, wherein
In the post-treatment step, after the drying step, the obtained lithium nickel composite oxide and a compound of at least one element selected from the group consisting of aluminum, boron, titanium, zirconium, and tungsten are mixed to prepare a surface of the lithium nickel composite oxide. A method for producing a lithium nickel composite oxide comprising a coating step of coating with a compound of the element. The method of claim 4, wherein
In the post-treatment step, a method for producing a lithium nickel composite oxide comprising a coating step of mixing the obtained lithium nickel composite oxide and an aluminum compound after the drying step and coating the aluminum compound on the surface of the lithium nickel composite oxide. The method according to any one of claims 6 to 10,
In the post-treatment step, the total amount of residual sulfate sulfate and residual lithium carbonate in the lithium nickel composite oxide obtained after the drying step is 0.6% by mass or less with respect to the total mass of the lithium nickel composite oxide, and the content of sodium is lithium nickel composite A method for producing a lithium nickel composite oxide, which is treated to be 50 ppm or less with respect to the total mass of the oxide.

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