KR20110121274A - Method of preparing lithium transition metal oxide - Google Patents

Abstract

PURPOSE: A method for manufacturing lithium transition metal oxide is provided to obtain uniform lithium transition metal oxide(LiNi_xCo_1-x-yMn_yO_2) nano particles by mixing reacting materials before lithium transition metal oxide particles are grown. CONSTITUTION: A method for manufacturing lithium transition metal oxide includes the following: Reacting materials containing lithium, nickel, cobalt, and manganese are introduced into a reactor and are mixed at the molecular level in the reactor. The reacting materials are chemically reacted to generate a crystalline nucleus. The chemical reaction is an acid-base reaction. The reacting materials include an acidic material and a base material. A time(TM) required for a mixing process is shorter than a time(TN) required for a crystalline nucleating process. The molar ratio of nickel to lithium, the molar ratio of cobalt to lithium, and the molar ratio of manganese to lithium are respectively 1 or less. The molar ratio of Ni+Co+Mn to lithium is 1 or less. A reactor(10) is a high-gravity rotating packed-bed reactor.

Description

 Method of preparing lithium transition metal oxide

Disclosed is a method for producing a lithium transition metal oxide. More specifically, injecting a reaction raw material including lithium, nickel, cobalt and manganese into the reactor, mixing at the molecular level and chemical reaction (nucleating) by the chemical reaction (chemical reaction) Disclosed is a method for producing a lithium transition metal oxide comprising a.

Lithium transition metal oxide (LiNi _x Co _{1 -x- y} Mn _y O ₂ : 0 <x <1, 0 <y <1, 0 <x + y <1, hereinafter referred to as NCM) is a positive electrode of a lithium secondary battery It is a material that is expected to be used as an active material.

As a manufacturing method of such NCM, there exist a solid-state method and a coprecipitation method, for example.

The solid phase method is a method for producing an NCM by mixing and heat treating a solid phase reaction raw material, and it is difficult to manufacture uniform nanoparticles due to high heat treatment temperature, and to produce uniform nanoparticles of fine particles of several hundred nanometers or less. since the need to use a reactive raw material becomes high reliance on the reaction raw materials falls price competitiveness, a short can be synthesized NCM daily (單一相) is not LiNiO _2, LiCoO ₂ and LiMnO _2, etc. mixed phase (混合相) Fig synthesis of There is a problem.

The coprecipitation method is a method for producing an NCM by using an acidic group reaction, but it is possible to synthesize a single phase NCM having a planar structure.

One embodiment of the present invention is to inject a reaction raw material containing lithium, nickel, cobalt and manganese into the reactor to mix at the molecular level (chemical level) and chemical reaction (chemical reaction) to generate nucleating (nucleating) It provides a method for producing a lithium transition metal oxide comprising the step of.

One aspect of the invention,

Injecting a reaction raw material including lithium, nickel, cobalt and manganese into a reactor and mixing at the molecular level in the reactor; And

It provides a method for producing a lithium transition metal oxide comprising the step of chemical reaction (nucleating) the reaction raw material in the reactor (nucleating).

The chemical reaction may be an acid group reaction.

The reaction raw material may be injected into the reactor in the form of at least one of a solution form and a suspension form.

The reaction raw material may include an acidic raw material and a basic raw material, the acidic raw material may be injected into the reactor through a first raw material injection line, and the basic raw material may be injected into the reactor through a second raw material injection line.

The acidic raw material may include lithium, nickel, cobalt and manganese, and the basic raw material may include a metal hydroxide.

The acidic raw material may include nickel, cobalt and manganese, and the basic raw material may include lithium.

The acidic raw material may include lithium, and the basic raw material may include nickel, cobalt, and manganese.

The basic raw material may include lithium, nickel, cobalt, and manganese, and the acidic raw material may include at least one of an inorganic acid and an organic acid.

The time (T _M ) required for mixing at the molecular level may be shorter than the time (T _N ) required for nucleation.

The T _M may be 10 to 100 μs, and the T _N may be 1 μm or less.

The molar ratio of nickel to lithium (Ni / Li), cobalt (Co / Li) and manganese (Mn / Li) in the reaction raw materials are less than 1, respectively, and the molar ratio of (nickel + cobalt + manganese) (( Ni + Co + Mn) / Li) may be 1 or less.

The reactor includes a chamber defining an internal space, a rotatable permeable packed bed disposed in the chamber and filled with a porous filler, and at least one raw material for injecting the reaction material into the permeable packed layer. It may be a high gravity rotating packed bed reactor having a slurry discharge port for discharging the slurry from the injection line and the inner space.

Centrifugal acceleration of the permeable packed layer may be maintained at 10 ~ 100,000 m / s ² .

According to one embodiment of the present invention, a reaction raw material containing lithium, nickel, cobalt and manganese in the form of inexpensive chloride and / or hydrate is injected into a reactor, mixing at the molecular level and chemical reaction The method of producing a lithium transition metal oxide capable of mass-producing NCM having a particle size of several hundred nanometers or less and having a uniform particle size distribution and high purity at a low cost by including a step of nucleating by reaction) Can be provided.

1 is a cross-sectional view schematically showing a high gravity rotary packed bed reactor used in the method for producing a lithium transition metal oxide according to one embodiment of the present invention.
2, 4, 6 and 8 are TEM photographs of the lithium transition metal oxide nanoparticles prepared in each embodiment of the present invention.
3, 5, 7 and 9 are XRD diffraction patterns of the lithium transition metal oxide nanoparticles prepared in each embodiment of the present invention.

Next, a method of manufacturing a lithium transition metal oxide according to an embodiment of the present invention will be described in detail.

Method for producing a lithium transition metal oxide according to an embodiment of the present invention is a step of injecting a reaction raw material containing lithium, nickel, cobalt and manganese into the reactor mixing at the molecular level in the reactor (mixing at the molecular level) And chemically reacting the reaction raw materials in the reactor to produce nucleating crystals and growing them to nanoscale. Thereafter, the slurry discharged from the reaction may be filtered, washed, dried and / or heat treated to obtain a uniform nano-sized lithium transition metal oxide (NCM).

In the present specification, 'lithium' means a lithium compound, a lithium atom and / or a lithium ion in some cases, and 'nickel' means a nickel compound, a nickel atom and / or a nickel ion in some cases, and 'cobalt' Optionally, it means a cobalt compound, a cobalt atom and / or a cobalt ion, and "manganese" optionally means a manganese compound, a manganese atom and / or manganese ions.

In addition, in the present specification, the "molecular level of mixing" means the level of mixing at which each molecule is mixed. In general, 'mixing' can be divided into 'macro-mixing' and 'micro-mixing', where macro mixing means mixing at the vessel scale, Micro mixing is synonymous with mixing at the molecular level described above.

The reaction raw material may be injected into the reactor in the form of at least one of a solution form and a suspension form.

In addition, the reaction raw material may include an acid raw material and a basic raw material. In this case, the acidic raw material may be injected into the reactor through a first raw material injection line, and the basic raw material may be injected into the reactor through a second raw material injection line. Specifically, the acidic raw material and the basic raw material are injected into the reactor through the first raw material injection line and the second raw material injection line, respectively, mixed at the molecular level in the reactor, and then subjected to a chemical reaction such as an acid group reaction. NCM nanoparticles will be formed.

The acidic raw material may include lithium, nickel, cobalt and manganese. Specifically, the acidic raw material may include lithium chloride, nickel chloride, cobalt chloride and manganese chloride. The acidic raw material may be, for example, a mixed aqueous solution of LiCl / NiCl ₂ / CoCl ₂ / MnCl ₂ or a mixed aqueous suspension. In this case, the basic raw material may include a metal hydroxide such as NaOH.

In addition, the acidic raw material may include nickel, cobalt and manganese, and the basic raw material may include lithium. Specifically, the acidic raw material may include nickel chloride, such as NiCl ₂ , cobalt chloride, such as CoCl _2, and manganese chloride, such as MnCl _2, and the basic raw material may include lithium hydroxide, such as LiOH.

In addition, the acidic raw material may include lithium, and the basic raw material may include nickel, cobalt and manganese. Specifically, the acidic material is a manganese hydroxide as the basic raw material containing lithium chloride such as LiCl, and the Ni (OH) ₂ as a nickel hydroxide, Co (OH) cobalt hydroxide and Mn (OH) _2, such as _2, such as It may include.

In addition, the basic raw material may include lithium, nickel, cobalt and manganese. Specifically, the basic raw material may include lithium hydroxide, nickel hydroxide, cobalt hydroxide and manganese hydroxide. The basic raw material may be, for example, a mixed aqueous solution or a mixed aqueous suspension of LiOH / Ni (OH) ₂ / Co (OH) ₂ / Mn (OH) ₂ . In this case, the acidic raw material may include an inorganic acid and / or an organic acid such as HCl or acetic acid.

Such lithium chloride, nickel chloride, cobalt chloride, manganese chloride, lithium hydroxide, nickel hydroxide, cobalt hydroxide and manganese hydroxide is low price can reduce the manufacturing cost of lithium transition metal oxide nanoparticles.

The chemical reaction may be an acid group reaction in which the acid and the base in the reaction raw material react by one equivalent, thereby losing the properties of the acid and the base.

The time (T _M ) required for mixing at the molecular level may be shorter than the time (T _N ) required for nucleation.

In the present specification, 'T _M ' refers to the time taken from the start of mixing until the composition of the mixture becomes spatially uniform, and 'T _N ' means that the seed formation rate is in equilibrium from the point where the seed starts to form. It means the time it takes to reach and produce seed at a constant rate.

As such, by adjusting T _M to be shorter than T _N , when the maximum mixing between molecules is achieved before the start of nucleation in the reactor, NCM particles having a uniform particle size distribution can be prepared.

The T _M may be 10 to 100 μs, and the T _N may be 1 μm or less. If the T _M is less than 10 GPa, it is not preferable from the economical point of view, and if it exceeds 100 GPa, the particle size uniformity is inferior, which is not preferable. In addition, when the T _N exceeds 1 kPa, an appropriate level of reaction does not occur and thus yield is not preferable.

In the preparation of the NCM nanoparticles, the internal temperature of the reactor may be maintained at 0 ~ 90 ℃, for example, 20 ~ 80 ℃. It is not preferable because the temperature to secure appropriate level of yield is less than 0 ℃, if it exceeds 90 ℃ undesirable control of T _N becomes difficult.

In addition, the molar ratio of nickel to lithium (Ni / Li), cobalt (Co / Li) and manganese (Mn / Li) in the reaction raw materials are less than 1, respectively, and the molar ratio of (nickel + cobalt + manganese). ((Ni + Co + Mn) / Li) may be 1 or less. The molar ratios (Ni / Li, Co / Li, Mn / Li, (Ni + Co + Mn) / Li) have values within the respective numerical ranges, whereby LiNi _x Co _{1 -xy} Mn _y O ₂ (0 < NCMs with chemical structures of x <1, 0 <y <1, 0 <x + y <1) can be prepared.

The residence time of the reaction raw material in the reactor may be 1㎳ ~ 10s, for example, 10㎳ ~ 5s. If the residence time of the reaction raw material is less than 1㎳ is not preferable because the appropriate level of the reaction does not occur, if it exceeds 10s, it is difficult to control the particle size of the NCM, it is not preferable because the economy is poor.

FIG. 1 is a schematic cross-sectional view of a high gravity rotating packed bed reactor used in a method of manufacturing a lithium transition metal oxide according to one embodiment of the present invention.

This high gravity rotary packed reactor 10 is a chamber 11 defining an interior space, a rotatable permeable packed bed disposed in the chamber 11 and filled with a porous filler 12a ( 12) at least one raw material injection line 14-1, 14-2 for injecting the reaction raw material into the transparent filling layer 12; And a slurry outlet 15 for discharging the slurry from the inner space.

The raw material injection lines 14-1 and 14-2 are disposed to extend through the reactor 10 to the center of the rotating shaft of the permeable packed layer 12, and a plurality of injection holes (not shown) are formed at each end of the reactor. The reaction raw material injected into (10) is sprayed into the transparent packed layer 12.

In addition, the reactor 10 may further include a gas outlet 16 for discharging gas from the internal space.

Porous filler 12a may contain titanium which is highly corrosion resistant. Specifically, the porous filler 12a may be titanium foam.

The permeable filler layer 12 is filled with a porous filler 12a therein and transmits the reaction raw material injected into the reactor 10 in the form of a solution or a suspension, and may be rotated by the drive shaft 13. The centrifugal acceleration of the permeable filler 12 can be maintained at 10 ~ 100,000 m / s ² . If the centrifugal acceleration of the permeable packed layer 12 is less than 10 m / s ^{2, the} reaction may not proceed to an appropriate level. On the other hand, it is not easy in the reactor design technology that the centrifugal acceleration of the permeable packed layer 12 exceeds 100,000 m / s ² .

Although the reactor 10 having the above configuration is operated under atmospheric pressure, the reaction raw materials can be mixed at a molecular level by a large centrifugal force by controlling the rotational speed of the permeable packed bed 12, so that the reaction proceeds smoothly even at low temperatures. You can. That is, uniform NCM nanoparticles can be obtained at low temperature by mixing the reaction material of the fine droplets well before the growth of the NCM particles. In addition, the reactor 10 is a continuous reactor can be produced in large quantities NCM.

NCM prepared by the method for producing a lithium transition metal oxide according to an embodiment of the present invention may have an average particle diameter of 0.01 ~ 10㎛, for example, 0.05 ~ 0.8㎛. Therefore, the prepared lithium transition metal oxide may be used as a cathode active material of a lithium secondary battery.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these embodiments.

Example

Example  One

(1) 6.0 mol / L aqueous NaOH solution was prepared and used as the basic raw material.

(2) 2.0 mol / L LiCl aqueous solution, 2.0 mol / L NiCl ₂ aqueous solution, 2.0 mol / L CoCl ₂ aqueous solution and 2.0 mol / L MnCl ₂ aqueous solution were prepared, respectively. The mixture was mixed with each other in a volume ratio of 1: 1: 1 to use the mixed solution as an acidic raw material. At this time, the molar ratio of Ni (Ni / Li), the molar ratio of Co (Mn / Li), and the molar ratio of Mn (Mn / Li) to Li in the LiCl / NiCl ₂ / CoCl ₂ / MnCl ₂ mixed aqueous solution were each 1/3. .

(3) A reactor 10 similar to the reactor of FIG. 1 was manufactured by itself. The specifications of the manufactured reactor 10 were as follows.

Permeable filler layer 12: cylindrical stainless steel material, inner diameter 10 cm, outer diameter 30 cm, thickness 10 cm.

Porous filler (12a): four titanium foams (approximately 400 voids per meter, outer diameter 30cm, inner diameter 10.5cm, axial thickness 2.5cm)

(4) In order to manufacture the NCM nanoparticles, the drive shaft 13 of the reactor 10 is rotated to rotate the permeable packed bed 12 at a speed of 1440 rpm (central acceleration: 60,000 m / s ² ) while the reactor 10 ) Was maintained at 80 ° C.

(5) The acidic raw material prepared in the above (2) and the basic raw material prepared in the above (1) are respectively passed through the first raw material injection line 14-1 and the second raw material injection line 14-2. 10) was continuously injected at a flow rate of 40 L / min to obtain NCM nanoparticles.

(6) The slurry containing the prepared NCM nanoparticles was discharged to the slurry outlet 15.

(7) The slurry was filtered with a filter, washed with water, and dried at a temperature of 120 ° C. in a dryer to obtain NCM nanoparticles.

Example  2

Aqueous solution of 2.0 mol / L of LiOH was prepared and used as a basic raw material, 2.0 mol / L of NiCl ₂ aqueous solution, 2.0 mol / L of CoCl ₂ and 2.0 mol / L of MnCl ₂ aqueous solution were prepared, respectively, NCM nanoparticles were mixed in the same manner as in Example 1, except that the aqueous solution was mixed with each other in a volume ratio of 1: 1: 1, and the mixed solution was used as an acidic raw material, and the internal temperature of the reactor was maintained at 90 ° C. Was prepared, filtered, washed and dried to obtain NCM nanoparticles. In this embodiment, the ratio of the reaction raw material components injected into the reactor 10, that is, the molar ratio of Ni to Li (Ni / Li), the molar ratio of Co to Li (Co / Li) and the molar ratio of Mn to Li (Mn / Li) was each 1/3.

Example  3

A 6.0 mol / L aqueous LiCl solution was prepared and used as an acidic raw material, a 2.0 mol / L aqueous Ni (OH) ₂ solution, a 2.0 mol / L aqueous Co (OH) ₂ solution and 2.0 mol / L Mn (OH) ₂ After each of the aqueous solutions were prepared, the three aqueous solutions were mixed with each other in a volume ratio of 1: 1: 1, and the mixed solution was used as a basic raw material, and the internal temperature of the reactor was maintained at 60 ° C. Except that the basic raw materials are continuously injected into the reactor 10 at a flow rate of 20 L / min and 60 L / min through the first raw material injection line 14-1 and the second raw material injection line 14-2, respectively. Then, NCM nanoparticles were prepared in the same manner as in Example 1, filtered, washed and dried to obtain NCM nanoparticles. In this embodiment, the ratio of the reaction raw material components injected into the reactor 10, that is, the molar ratio of Ni to Li (Ni / Li), the molar ratio of Co to Li (Co / Li) and the molar ratio of Mn to Li (Mn / Li) was each 1/3.

Example  4

A 6.0 mol / L aqueous HCl solution was prepared and used as an acidic raw material. A 2.0 mol / L aqueous LiOH solution, a 2.0 mol / L aqueous Ni (OH) ₂ solution, a 2.0 mol / L aqueous Co (OH) ₂ solution and 2.0 mol / L aqueous solution of Mn (OH) ₂ , respectively, and the four aqueous solutions were mixed with each other in a volume ratio of 3: 1: 1: 1 to use the mixed solution as a basic raw material, and the internal temperature of the reactor was 60 And the acidic raw material and the basic raw material are respectively 50L / min and 25L / in the reactor 10 through the first raw material injection line 14-1 and the second raw material injection line 14-2, respectively. Except for continuously injecting at a flow rate of min, NCM nanoparticles were prepared in the same manner as in Example 1, filtered, washed and dried to obtain NCM nanoparticles.

In this embodiment, the ratio of the reaction raw material components injected into the reactor 10, that is, the molar ratio of Ni to Li (Ni / Li), the molar ratio of Co to Li (Co / Li) and the molar ratio of Mn to Li (Mn / Li) was each 1/3.

Analysis example

TEM photographs and XRD diffraction patterns of the lithium transition metal oxide nanoparticles prepared in Examples 1 to 4 were analyzed and shown in FIGS. 2 to 9, respectively. The specifications and analysis conditions of the TEM and XRD used are shown in Table 1 below.

TEM XRD Specifications manufacturer JEOL Rikagu model name 2100F D / Max-2500VK / PC Analysis condition 200 kV CuKa radiation, speed 4 ° min ^-1

Referring to Figures 2 to 9, despite the use of inexpensive reaction raw material it can be seen that the NCM particles having a relatively uniform particle size distribution and nano-size can be obtained. Specifically, it can be seen from FIGS. 2, 4, 6, and 8 that the particles prepared in Examples 1 to 4 have a nano size and that the particle size distribution of each particle is uniform, and FIGS. 3, 5, and 7 From 9 and 9 it can be seen that each of the particles prepared is NCM (LiNi _x Co _{1 -x- y} Mn _y O ₂ : 0 <x <1, 0 <y <1, 0 <x + y <1) have. Each numerical value (e.g., 100 nm in Fig. 2) shown in Figs. 2, 4, 6 and 8 means the length of the thick bar shown in each figure, and each numerical value indicated in Figs. For example, (111) of FIG. 3 means a crystal plane index.

Although preferred embodiments of the present invention have been described above with reference to the drawings and embodiments, these are merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. You will understand. Therefore, the protection scope of the present invention should be defined by the appended claims.

10: high gravity rotary packed bed reactor 11: chamber
12: permeable filler layer 12a: porous filler
13: drive shaft 14-1, 14-2: raw material injection line
15: slurry outlet 16: gas outlet

Claims (13)

Injecting a reaction raw material including lithium, nickel, cobalt and manganese into a reactor and mixing at the molecular level in the reactor; And
A method for producing a lithium transition metal oxide comprising the step of chemically reacting the reaction raw material in the reactor (nucleating). The method of claim 1,
The chemical reaction is an acid group reaction method for producing a lithium transition metal oxide. The method of claim 1,
The reaction raw material is a method of producing a lithium transition metal oxide is injected into the reactor in the form of at least one of a solution form and a suspension form. The method of claim 3,
The reaction raw material includes an acid raw material and a basic raw material, the acid raw material is injected into the reactor through a first raw material injection line, and the basic raw material is a lithium transition metal oxide injected into the reactor through a second raw material injection line Manufacturing method. The method of claim 4, wherein
The acidic raw material includes lithium, nickel, cobalt and manganese, and the basic raw material is a method of producing a lithium transition metal oxide containing a metal hydroxide. The method of claim 4, wherein
The acidic raw material includes nickel, cobalt and manganese, and the basic raw material comprises a lithium transition metal oxide. The method of claim 4, wherein
The acidic raw material includes lithium, and the basic raw material is a method of producing a lithium transition metal oxide containing nickel, cobalt and manganese. The method of claim 4, wherein
The basic raw material includes lithium, nickel, cobalt and manganese, and the acidic raw material comprises at least one of an inorganic acid and an organic acid. The method of claim 1,
The time (T _M ) required for the mixing of the molecular level is shorter than the time (T _N ) for the production of nuclei. 10. The method of claim 9,
The T _M is 10 ~ 100㎲, and wherein _N T is greater than 1㎳ method for manufacturing a lithium transition metal oxide. The method of claim 1,
The molar ratio of nickel to lithium (Ni / Li), cobalt (Co / Li) and manganese (Mn / Li) in the reaction raw materials are less than 1, respectively, and the molar ratio of (nickel + cobalt + manganese) (( Ni + Co + Mn) / Li) is 1 or less lithium transition metal oxide manufacturing method. The method of claim 1,
The reactor,
A chamber defining an interior space;
A rotatable permeable packed bed disposed in said chamber and filled with a porous filler;
At least one raw material injection line for injecting the reaction raw material into the transparent packing layer; And
A method of producing a lithium transition metal oxide, which is a high gravity rotating packed bed reactor having a slurry outlet for discharging a slurry from the internal space. The method of claim 12,
Centrifugal acceleration of the permeable packed layer is a method of producing a lithium transition metal oxide is maintained at 10 ~ 100,000 m / s ² .

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