KR101217453B1 - Method of producing Ni- composite metal hydroxide, Ni-composite metal hydroxide obtained thereby - Google Patents

Abstract

The present invention relates to a nickel-based composite metal hydroxide which is a precursor for a lithium secondary battery cathode active material of spherical or oval shape and a method for manufacturing the same. More specifically, the nickel-based composite metal hydroxide is Co, Mn, Fe, Mg, Ti, Cu, It contains at least one element selected from Zn, Al, Ca, V, Cr, Mo, nickel-based by adjusting the equivalence ratio to 0.4 or less after the equivalent ratio of the precipitant / metal salt to 1.4 or more in the preparation by the coprecipitation method Provided is a method for preparing a nickel-based composite metal hydroxide which is a precursor for a lithium secondary battery cathode active material having high thermal stability by controlling the average particle size of the composite metal hydroxide larger than 20㎛.

Composite Metal Hydroxide, Coprecipitation Method, Nickel Composite System

Description

Nickel-based composite metal hydroxide, a precursor for lithium secondary battery cathode active materials, and a method of manufacturing the same {Method of producing Ni-composite metal hydroxide, Ni-composite metal hydroxide obtained}

The present invention relates to a method for controlling particle size and particle size distribution of a nickel-based composite metal hydroxide used as a raw material of a cathode active material for a lithium secondary battery.

In recent years, as electronic devices become smaller and more portable, demand for lighter, energy-rich lithium ion secondary batteries instead of nickel / cadmium batteries and nickel hydrogen batteries is increasing. In addition, in the case of batteries used for HEV and EV, not only high capacity and high power but also thermal stability remain a big problem. As the positive electrode active material of the lithium ion secondary battery inserts lithium ions? Has desorbed is a layered compound of LiNiO _2, LiCoO _2, LiMnO ₂ are known as possible. Among them, LiNiO ₂ has received a lot of attention because of its high electric capacity. However, LiNiO ₂ is not practical due to problems in cycle characteristics, storage stability, and high temperature stability in charging and discharging, and LiNi _(1-xy) Co _x having Mn and Co substituted in place of Ni to compensate for this drawback. Mn _y O ₂ is commercially available.

In particular, even in the same LiNi _(1-xy) Co _x Mn _y O _{2 The} safety is different depending on the size of the particles, the larger the particles, the higher the safety.

Solid phase method and coprecipitation method are generally used to synthesize LiNi _(1-xy) Co _x Mn _y O _{2. In} the solid phase method, raw materials of Ni, Co, Mn and Li are mixed and pulverized. As a method of obtaining an active material, it is difficult to obtain particles having a uniform composition even after grinding, and in the case of the coprecipitation method, an aqueous solution containing a raw material containing Ni, Co, and Mn salts, an aqueous alkali solution used as a precipitant, and a chelate used as a complexing agent It is easy to obtain an active material by mixing with a lithium source using a composite metal hydroxide obtained by a method of simultaneously dropping a solution as a precursor and firing it, but it is easy to obtain particles having a uniform composition, but the particle size of the active material greatly affects the particle size of the precursor. The crystal spheres of the active material are hardly fired at high temperature or grown for a long time in order to make the active material large using a small precursor particle. And the vulnerable haejyeoseo causing the deterioration of battery characteristics.

In the case of synthesizing the nickel-based composite metal hydroxide used as a precursor of LiNi _(1-xyz) Co _x Mn _y M _z O ₂ by coprecipitation method, the average particle size is about 5 to 20 μm as in JP 2008-195608 It is common to make particles of more than 20㎛. In order to make particles larger than 20㎛, a large amount of particles can be obtained by remarkably increasing the reaction time or by reducing agitation power. I do not lose.

The present invention is to solve the problems of the prior art as described above, after the addition of the equivalent ratio of the precipitant / metal salt to 1.4 or more during the preparation of the nickel-based composite metal hydroxide of the nickel-based composite metal hydroxide by adjusting the equivalent ratio to 0.4 or less Particles with an average particle size greater than 20 μm can be formed.

The present invention to achieve the above object,

It is represented by the following formula (1), provides a nickel-based composite metal hydroxide having an average particle size larger than 20㎛. The composite metal hydroxide is produced in an inert environment or in the presence of a reducing agent, and the reducing agent is preferably hydrazine.

[Formula 1]

Ni _(1-xyz) Co _x Mn _y M _z (OH) ₂

(In Formula 1, M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, x, y, z is not particularly limited, but 0 <x ≤ 1/3, 1/10 ≤ y ≤ 1/2, 0 ≤ z ≤ 1/10)

In another embodiment of the present invention is represented by the following formula (2), provides a nickel-based composite metal oxyhydroxide having an average particle size larger than 20 ㎛. The composite metal oxyhydroxide is produced in an active environment or in the presence of an oxidizing agent, and the oxidizing agent is preferably hydrogen peroxide (H ₂ O ₂ ).

(2)

Ni _(1-xyz) Co _x Mn _y M _z OOH

Wherein M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, and x, y, and z are not particularly limited, but 0 <x≤1 / 3, 1 / 10≤y≤1 / 2, 0≤z≤1 / 10

The present invention comprises the steps of forming a seed by putting a metal salt aqueous solution, a precipitating agent and a complexing agent; Growing the particles rapidly by adding an equivalent ratio of the precipitant / metal salt to 1.4 or more and then adjusting the equivalent ratio to 0.4 or less; And it provides a method for producing a nickel-based composite metal hydroxide batch reaction comprising the step of maintaining the equivalent ratio of the precipitant / metal salt to 1.0 to increase the density of the particles, nickel-based composite metal hydroxide is represented by the following formula 1 and the average particle size Is characterized by forming particles larger than 20 mu m.

[Formula 1]

Ni _(1-xyz) Co _x Mn _y M _z (OH) ₂

Wherein M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, and x, y, and z are not particularly limited, but 0 <x≤1 / 3, 1 / 10≤y≤1 / 2, 0≤z≤1 / 10

The preparation process by the nickel-based composite metal hydroxide batch reaction is carried out in an inert environment or in the presence of a reducing agent, the reducing agent is preferably used hydrazine (hydrazine).

According to another embodiment of the present invention to form a mother particle (seed) by putting an aqueous metal salt solution, a precipitating agent and a complex salt; Growing the particles rapidly by adding an equivalent ratio of the precipitant / metal salt to 1.4 or more and then adjusting the equivalent ratio to 0.4 or less; And it provides a method of producing a nickel-based composite metal oxyhydroxide batch reaction comprising the step of maintaining the equivalent ratio of the precipitant / metal salt to 1.0 to increase the density of the particles, nickel-based composite metal oxyhydroxide is represented by the formula It is characterized by forming particles having a particle size larger than 20 μm.

[Formula 2]

Ni _(1-xyz) Co _x Mn _y M _z OOH

Wherein M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, and x, y, and z are not particularly limited, but 0 <x≤1 / 3, 1 / 10≤y≤1 / 2, 0≤z≤1 / 10

The nickel-based composite metal oxyhydroxide batch reaction is carried out in an active environment or in the presence of an oxidizing agent, and the oxidizing agent is preferably hydrogen peroxide (H ₂ O ₂ ).

According to the manufacturing method of the present invention, Ni _(1-xyz) Co _x Mn _y M, which is an allele larger than 20 μm, which is difficult to be produced by the conventional method in the preparation of a nickel-based composite metal hydroxide used as a precursor of a cathode active material for a lithium secondary battery _Z (OH) ₂ can be synthesized with a short reaction time, and thus, the active material LiNi _(1-xyz) Co _x Mn _y M _z O _{2 can} also be synthesized to the required size and is commercially useful.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

Nickel-based composite metal hydroxide according to an embodiment of the present invention is represented by the following formula 1, characterized in that the average particle size is larger than 20㎛. The composite metal hydroxide is produced in an inert environment or in the presence of a reducing agent, and the reducing agent is preferably hydrazine.

[Formula 1]

Ni _(1-xyz) Co _x Mn _y M _z (OH) ₂

(In Formula 1, M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, x, y, z is not particularly limited, but 0 <x ≤ 1/3, 1/10 ≤ y ≤ 1/2, 0 ≤ z ≤ 1/10)

Nickel-based composite metal oxyhydroxide according to another embodiment of the present invention is represented by the following formula (2), characterized in that the average particle size is larger than 20㎛. The composite metal oxyhydroxide is produced in an active environment or in the presence of an oxidizing agent, and the oxidizing agent is preferably hydrogen peroxide (H ₂ O ₂ ).

(2)

Ni _(1-xyz) Co _x Mn _y M _z OOH

Wherein M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, and x, y, and z are not particularly limited, but 0 <x≤1 / 3, 1 / 10≤y≤1 / 2, 0≤z≤1 / 10

As the metal salt compound used as a raw material of the metal salt in the composite metal hydroxide or composite metal oxyhydroxide, one or more compounds containing a divalent (2+) metal salt such as sulfate-based, nitrate-based or chloride-based may be selected and used. The compound is dissolved in distilled water and used as an aqueous solution. At this time, the concentration of the metal salt aqueous solution is suitably 1.0 to 5.0 mol / l, and particularly preferably 1.5 to 3.0 mol / l.

In addition, as the precipitating agent, one or more alkali metal aqueous solution may be selected and used. Particularly, NaOH is preferably used. In this case, the concentration of NaOH aqueous solution is preferably 4 to 10 mol / l.

The particle diameter of the nickel-based composite metal hydroxide or composite metal oxyhydroxide according to the present invention is the most characteristic part of larger than 20㎛, which is possible by using a method of controlling the equivalent ratio to a specific ratio. In the case of existing nickel-based composite metal hydroxides, the average particle radius is generally about 5 to 20 µm when synthesized by coprecipitation. In order to make particles larger than 20 µm, the reaction time is significantly increased or the stirring force is decreased. Although it is possible to produce particles to a certain extent, it is possible to improve the productivity by reducing the amount or obtaining the particles of the desired form by adjusting the equivalent ratio according to the present invention.

Adjusting the equivalence ratio according to the present invention is characterized in that the equivalent ratio of the precipitant / metal salt is added to 1.4 or more to make the state of OH ^- ion excess, and then controlled to the equivalent ratio of 0.4 or less to rapidly grow the particles. That is, the amount of NaOH as a precipitant may be injected so that the equivalent ratio is 1.4 or more, and then adjusted to 0.4 or less to prepare particles having an average particle size larger than 20 μm.

When an equivalent ratio of precipitant / metal salt is added to 1.4 or more in an atmosphere in which a certain amount of seed is present, an excessive amount of OH- ⁻ ions is present. After adjusting the equivalence ratio to 0.4 or less, M ^{2 +} metal ions react rapidly with OH ^- ions in the reaction solution and do not form new particles, but combine with the adjacent particles (seed). The particle size grows rapidly.

On the other hand, in the case of the existing Japanese patent, the equivalent ratio of the precipitant / metal salt is produced by the method of controlling the pH, which is almost maintained at 1, so that the growth of particles and the formation of new particles are also performed. Only composite metal hydroxides of size or less are produced, making it difficult to produce an average particle size larger than 20 mu m.

In the composition according to the present invention, it is based on the method for producing high density nickel hydroxide, but is reacted while adding an appropriate reducing agent or flowing an inert gas. Normally, sufficient agitation force is required to form dense particles, but at this time, unstable cobalt ions or manganese ions are partially oxidized due to air drying, and thus a high density product is not obtained. In order to suppress such oxidation, it manufactures in an inert gas atmosphere or adding a reducing agent. In this case, the reducing agent added is not particularly limited, but hydrazine is preferably used.

Manufacturing method

Nickel-based composite metal hydroxide batch production method according to an embodiment of the present invention comprises the steps of forming a seed by putting a metal salt aqueous solution, a precipitating agent and a complexing agent; Growing the particles rapidly by adding an equivalent ratio of the precipitant / metal salt to 1.4 or more and then adjusting the equivalent ratio to 0.4 or less; And maintaining the equivalence ratio of the precipitant / metal salt to 1.0 to increase the compactness of the particles, wherein the average particle size of the nickel-based composite metal hydroxide is greater than 20 μm.

[Formula 1]

Ni _(1-xyz) Co _x Mn _y M _z (OH) ₂

Wherein M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, and x, y, and z are not particularly limited, but 0 <x≤1 / 3, 1 / 10≤y≤1 / 2, 0≤z≤1 / 10

The preparation process by the nickel-based composite metal hydroxide batch reaction is carried out in an inert environment or in the presence of a reducing agent, the reducing agent is preferably used hydrazine (hydrazine).

In the nickel-based composite metal oxyhydroxide batch reaction according to another embodiment of the present invention, a step of forming a mother particle (seed) by putting an aqueous metal salt solution, a precipitating agent and a complexing agent; Growing the particles rapidly by adding an equivalent ratio of the precipitant / metal salt to 1.4 or more and then adjusting the equivalent ratio to 0.4 or less; And maintaining the equivalent ratio of the precipitant / metal salt to 1.0 to increase the density of the particles, it is represented by the formula 2 and characterized in that the average particle size of the nickel-based composite metal oxyhydroxide is formed larger than 20㎛.

[Formula 2]

Ni _(1-xyz) Co _x Mn _y M _z OOH

Wherein M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, and x, y, and z are not particularly limited, but 0 <x≤1 / 3, 1 / 10≤y≤1 / 2, 0≤z≤1 / 10

The nickel-based composite metal oxyhydroxide batch reaction is carried out in an active environment or in the presence of an oxidizing agent, and the oxidizing agent is preferably hydrogen peroxide (H ₂ O ₂ ).

The nickel-based composite metal hydroxide manufacturing method according to the present invention goes through the following three steps.

1) a predetermined amount of deionized water and a complexing agent in a sealed co-precipitation reactor, and then a metal salt aqueous solution and a precipitant to form a seed (seed);

2) A metal salt solution, a precipitant, and a complexing agent are simultaneously added dropwise to the reaction solution in which the seed particles are formed. In this case, an equivalent ratio of the precipitant / metal salt is added to 1.4 or more to make an OH ^- ion excess, and an equivalent ratio of 0.4 or less. Rapidly growing the particles by adjusting to;

3) simultaneously dropping an aqueous metal salt solution, a precipitant, and a complexing agent, wherein the precipitant and the metal salt are added in a 1: 1 equivalent weight to form particles densely;

Particle size is determined in the second phase of rapid growth of the three phases. If the equivalence ratio is 1.4 or less or 0.4 or more in the step of rapidly growing the particles, it is not preferable because the reaction time should be long to make it 20 µm or less or larger than 20 µm.

Hereinafter, the present invention will be described in detail based on the following Examples, but the following examples are provided to illustrate the present invention, and the present invention is not limited thereto. In the Examples and Comparative Examples of the present invention, the manufacturing method was performed by the following method. .

Example  One

(a) preparing a seed;

A 25 L sealed coprecipitation reactor was used to maintain a rotational speed of 300 rpm, a temperature of 50 ° C., 10 L of deionized water, and a total of 2 mol / L of metal salts (nickel sulfate, manganese sulfate, cobalt sulfate) and aqueous ammonia (ignition). 8), 8 mol / L of sodium hydroxide solution was added to form a seed. At this time, the concentration of ammonia added was 6g / ℓ, Ni ion concentration in the reactor was set to 1000ppm.

(b) the rapid growth phase of the particles;

A metal salt aqueous solution, sodium hydroxide solution, and ammonia water are added to a stirred coprecipitation reactor in which seed particles are formed. In this case, the total metal salt concentration of nickel sulfate, manganese sulfate, and cobalt sulfate was 2.0 mol / l, and the molar ratio of the metal salt solution was 5: 2: 3 of nickel: cobalt: manganese. Ml / min. Ammonia water was used as a 10wt% solution, and the feed rate was adjusted to 6g / ℓ. 8 mol / l of sodium hydroxide solution was used, and the feed rate was adjusted to maintain 1.6 in equivalence ratio of sodium hydroxide solution / metal salt solution, followed by 30 minutes, and then the aqueous metal salt solution and ammonia water in the absence of sodium hydroxide solution. Put in for 30 minutes.

(c) increasing the density of rapidly growing particles;

Into the coprecipitation reactor in which the suspension of the rapidly growing particles is stirred, the reaction rate of sodium hydroxide solution is adjusted so that the equivalence ratio of sodium hydroxide solution / metal salt solution is 1.0 equivalent, and the reaction is carried out with a metal salt solution, sodium hydroxide solution and ammonia water for 10 hours. , And aged for 1 hour in the absence of input to complete the particles. In Example 1 above, a nickel-based composite metal hydroxide having an average particle diameter of 33 μm was obtained, and the composition of the nickel-based composite metal hydroxide was confirmed to satisfy Formula 1 as Ni _0.5 Co _0.2 Mn _0.3 (OH) ₂ . On the other hand, DSC results of the active material synthesized with such a precursor showed a calorific value of 928J / g.

Example  2

After maintaining the equivalence ratio 1.8 for 30 minutes in the rapid growth stage (b) of the particles, the particles were completed in the same manner as in Example 1 except that the sodium hydroxide solution was adjusted to the equivalence ratio 0.2 and maintained for 30 minutes (Example 1 And composition is the same). In Example 2 described above, particles having an average particle diameter of 30 µm were obtained.

Example  3

After maintaining the equivalence ratio 1.4 for 30 minutes in the rapid growth step (b) of the particles, the particles were completed in the same manner as in Example 1 except that the sodium hydroxide solution was adjusted to the equivalence ratio 0.4 and maintained for 30 minutes (Example 1 And composition is the same). In Example 3, particles having an average particle diameter of 25 µm were obtained, and a calorific value of 1103 J / g was obtained by DSC of the active material synthesized with the precursor.

Comparative example  One

Using a 25 L sealed coprecipitation reactor, the rotation speed was maintained at 300 rpm, the temperature was maintained at 50 ° C., 10 L of deionized water was added, and a metal salt aqueous solution having a total of 2 mol / l metal salt, aqueous ammonia, and sodium hydroxide solution having 8 mol / l was added. Particles were formed. At this time, the concentration of ammonia added was 6g / ℓ, the pH in the reactor was 10.7.

A metal salt aqueous solution, sodium hydroxide solution, and ammonia water are added to a stirred coprecipitation reactor in which seed particles are formed. In this case, the total metal salt concentration of nickel sulfate, manganese sulfate, and cobalt sulfate was 2.0 mol / l, and the molar ratio of the metal salt solution was 5: 2: 3 of nickel: cobalt: manganese. Ml / min. Ammonia water was used as a 10wt% solution, and the feed rate was adjusted to 6g / ℓ.

The sodium hydroxide solution was 8 mol / l in concentration, and the sodium hydroxide solution input rate was adjusted so that the equivalence ratio of the sodium hydroxide solution / metal salt aqueous solution was 1.0 equivalent. The reaction was carried out while adding a metal salt aqueous solution, sodium hydroxide solution, and ammonia water for 10 hours at the above charging rate, followed by aging for 1 hour in the absence of addition, to complete the particles. The average particle diameter of the obtained nickel-based composite metal hydroxide was 15 μm. Particles were obtained, and DSC of the active material synthesized with this precursor showed a calorific value of 1205 J / g.

Comparative Example 2

Except having made the reaction time in the said comparative example 1 into 20 hours, it carried out similarly to the comparative example 1, and completed the particle | grain, and the average particle diameter of the obtained nickel-type composite metal hydroxide was 17 micrometers.

1 is a graph showing the particle size distribution of the nickel-based composite metal hydroxide obtained in Example 1. FIG.

2 is a graph showing the particle size distribution of the nickel-based composite metal hydroxide obtained in Comparative Example 1. FIG.

3 is a SEM (Scanning Electron Microscope) photograph of the nickel-based composite metal hydroxide obtained from Example 1. FIG.

FIG. 4 is a SEM (Scanning Electron Microscope) photograph of the nickel-based composite metal hydroxide obtained from Comparative Example 1.

5 is a DSC result graph of an active material made of a precursor having a ratio of Ni: Co: Mn obtained from Examples 1, 3, and Comparative Example 1, 5: 2: 3, respectively.

Claims (12)

delete delete delete delete delete delete In the production by a nickel-based composite metal hydroxide batch reaction that is a precursor for a lithium secondary battery cathode active material, Adding a metal salt aqueous solution, a precipitating agent and a complexing agent to form a seed; Growing the particles rapidly by adding an equivalent ratio of the precipitant / metal salt to 1.4 or more and then adjusting the equivalent ratio to 0.4 or less; And A nickel-based composite metal, which is a precursor for a lithium secondary battery cathode active material, which forms a particle having an average particle size greater than 20 μm, including the step of increasing the density of particles by maintaining the equivalence ratio of the precipitant / metal salt at 1.0. Process for the preparation of hydroxides. [Formula 1] Ni _(1-xyz) Co _x Mn _y M _z (OH) ₂ Wherein M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, and x, y, and z are not particularly limited, but 0 <x≤1 / 3, 1 / 10≤y≤1 / 2, 0≤z≤1 / 10 8. The method of claim 7, The lithium secondary battery cathode active material may be manufactured by a nickel-based composite metal hydroxide batch reaction in an inert atmosphere of 1% or less of oxygen, in the presence of a reducing agent of 0.5% by weight or less of the raw material solution, or in a simultaneous atmosphere. A method for producing a nickel-based composite metal hydroxide which is a precursor for metals. The method of claim 8, wherein the inert gas is nitrogen, and the reducing agent is hydrazine. 9. In the production by a nickel-based composite metal oxyhydroxide batch reaction, Adding a metal salt aqueous solution, a precipitating agent and a complexing agent to form a seed; Growing the particles rapidly by adding an equivalent ratio of the precipitant / metal salt to 1.4 or more and then adjusting the equivalent ratio to 0.4 or less; And The nickel-based composite metal, which is a precursor for a lithium secondary battery cathode active material, which forms a particle having an average particle size greater than 20 μm, including the step of increasing the density of particles by maintaining an equivalent ratio of a precipitant / metal salt at 1.0 Method for producing oxyhydroxide. [Formula 2] Ni _(1-xyz) Co _x Mn _y M _z OOH Wherein M is at least one element selected from Fe, Mg, Ti, Cu, Zn, Al, Ca, V, Cr, Mo, and x, y, and z are not particularly limited, but 0 <x≤1 / 3, 1 / 10≤y≤1 / 2, 0≤z≤1 / 10 11. The method of claim 10, The lithium secondary battery cathode active material may be manufactured by a nickel-based composite metal oxyhydroxide batch reaction in an active atmosphere of 20% or more of oxygen, or in the presence of an oxidizing agent of 0.5% by weight or less of the raw material solution, or in the same atmosphere. A method for producing a nickel-based composite metal oxyhydroxide which is a precursor. The method of claim 11, The active gas is oxygen or air, the oxidizing agent is a hydrogen peroxide (H ₂ O ₂ ), the method for producing a nickel-based composite metal oxy hydroxide as a precursor for a lithium secondary battery cathode active material.

Images