KR101510528B1 - Method for producing electrode active material agglomerates for lithium secondary battery by spray drying process and the electrode active material particles prepared therefrom - Google Patents

Abstract

The present invention provides a novel method for preparing agglomerates in which a plurality of nano powders are agglomerated and coagulated by a spray drying process, and an electrode active material powder for agglomerate structure produced by the method.
In the present invention, it is possible to replace a liquid phase process requiring synthesis of a secondary cell powder of a conventional aggregate structure with a high temperature and a large amount of organic matter by a simple gas phase process, It is possible to synthesize a new material having an agglomerate structure composed of nano powder of several nanometers in size with various compositions. Therefore, it can be effectively applied to all fields of cathode materials, anode materials, and the like in the field of secondary batteries.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrode active material powder for a lithium secondary battery having an agglomerate structure by a spray drying process and an electrode active material powder prepared therefrom,

The present invention relates to a novel synthesis technique of an electrode active material having an aggregate structure composed of nano powder and which can be usefully used in the field of secondary batteries and a method of synthesizing a positive electrode active material and a negative electrode active material powder of a lithium ion secondary battery having an aggregate structure, .

Generally, micron-sized powders used in secondary batteries are difficult to withstand high current density and are difficult to achieve high current and high capacity. Due to these problems, nano-sized powders are agglomerated to synthesize micron-sized powders. Because nanosized powders produce higher capacities at higher current densities and exhibit better electrochemical properties than micron sized powders. Nano-sized powders required for forming such aggregate structure are generally synthesized through a multistage process by a liquid phase process and a pulverization process. In the multi-step process by the liquid phase process, a plurality of raw materials are mixed to obtain a phase of a desired substance, but since they are not mixed uniformly, a large amount of organic matter and a high temperature are required, , Device problems in high-temperature synthesis, low crystallinity of ceramic powder, contamination of materials, and the like. Therefore, it is necessary to develop the technology by the meteorological process in order to develop the new material with high purity nano size powder structure.

The gas phase process is a synthesis process from low temperature to high temperature and is widely applied to the synthesis of metal powder materials with high crystallinity and high purity. Especially, spray pyrolysis process using liquid droplets in which metal components are dissolved is widely applied to mass production of metal powder materials having thin shells. Under these spray pyrolysis processes, it is economically problematic to synthesize nano-sized powders because of the need for organic materials and high temperature to make metal powder having a thin, thin shell.

On the other hand, the spray drying process is a low-temperature synthesis process in which liquid droplets are passed through a nozzle together with a gas at a high temperature to generate a large amount of thin metal powder, which is hollowed by instantaneous volume expansion and drying. , And silica are being commercially applied to the production of ceramic materials. However, there are few studies to obtain nanosize powders by pulverization process after obtaining particles with a thin shell by using a spray drying process. Therefore, there is a need to develop a nano-sized powder using a spray drying process and a new technique for synthesizing a material having an aggregate structure.

As described above, the present invention has been devised in order to develop a novel synthesis method for economically mass-producing nano-sized powders having an aggregate structure.

More specifically, in the present invention, liquid droplets containing various metal components are synthesized and heat-treated through a first spray-drying process to obtain a hollow ceramic ceramic primary shell having a thin shell and then pulverized to obtain a nano- The present inventors have developed a novel synthesis technique for synthesizing an electrode active material powder having an agglomerate structure composed of nano-sized powder by synthesizing powders, precisely controlling physical properties of the powder, and performing a second spray drying process.

Accordingly, the present invention provides a novel manufacturing method of synthesizing a secondary battery material having an aggregate structure made of nano-sized powder by the above two-step spray drying process, and a method of providing a secondary battery powder having an aggregate structure .

The present invention relates to a process for preparing a first spray solution comprising: (a) mixing a precursor containing at least one metal, a chelating agent and a solvent to form a first spray solution; (b) preparing primary particles in the form of a hollow sphere by first spray drying and heat treatment using the first spray solution; (c) pulverizing the produced primary particles in the form of hollow bodies to prepare nanoparticles; And (d) spray-drying the second spraying solution containing the nanoparticles to form spherical secondary particles in which a plurality of primary particles are assembled with each other to form agglomerated secondary particles. A method for producing an electrode active material powder is provided.

According to a preferred embodiment of the present invention, when the final electrode active material is a cathode active material or an anode active material, the precursors may be different from each other.

For example, when the electrode active material is a cathode active material, the precursor preferably includes at least one metal selected from the group consisting of Li, Ni, Co, Mn, Al, V, Fe, P and Cr, In the case of the negative electrode active material, the precursor preferably contains at least one metal selected from the group consisting of Li, Ti, Si, Co, Mn, Zn, Cu, Fe, Mo and Sn.

According to another preferred embodiment of the present invention, the chelating agent may be selected from the group consisting of a carboxylic acid having at least one carboxyl group, oxalic acid, ethylenediamine acetic acid, citric acid, and combinations thereof.

According to another preferred embodiment of the present invention, it is preferable that the manufacturing method further comprises a step of post-heat-treating the secondary particles formed in step (d) at 300 to 1,000 ° C in an air atmosphere or a nitrogen atmosphere.

The present invention also provides an electrode active material powder for a lithium secondary battery comprising spherical secondary particles agglomerated by agglomerating a plurality of primary nanoparticles and a lithium ion Thereby providing a secondary battery.

Here, the secondary battery electrode active material powder may be any one of a cathode material and an anode material.

According to the present invention, a complicated liquid phase process for synthesizing a secondary cell powder having a conventional aggregate structure can be replaced with gas phase processes, thereby providing an economical, mass-productivity, and environmentally friendly new manufacturing method.

In addition, since a novel material having an aggregate structure having uniform and various compositions can be synthesized, it is possible to provide powders of various compositions having an aggregate structure applicable to various fields such as secondary batteries and phosphors.

Further, by replacing the existing liquid phase process in which a problem such as a high temperature, a variety of organic matter residues, and a long reaction time is brought about in order to obtain a nano-sized powder having a uniform composition and a coagulated material, Of the nano-sized powder and the agglomerate structure made of the nano-sized powder can be easily synthesized.

Furthermore, it is possible to obtain secondary battery powders having various aggregate structures easily by controlling the composition of the spraying solution used in the spray drying process, and the size of the agglomerate powder can be easily controlled by adjusting the concentration of the slurry.

1 is a scanning electron microscope (SEM) and X-ray diffraction pattern of a precursor powder of hollow hollow structure synthesized by a first spray drying process according to Example 1 and a Co ₃ O ₄ powder obtained through heat treatment.
FIG. 2 is a scanning electron microscope (SEM) and a transmission electron microscope (TEM) photograph of the Co ₃ O ₄ powder prepared through post-heat treatment and pulverization according to Example 1.
FIG. 3 is a scanning electron microscope (SEM) image of a nano-sized powder obtained through a pulverizing process according to Example 1, which is produced as a powder of an aggregate structure through a second spray drying process.
FIG. 4 is a scanning electron microscope (SEM) photograph of the electrode active material powders prepared by changing the post-heat treatment temperature of the powder of the aggregate structure prepared in Example 1. FIG.
FIG. 5 is a graph showing a nitrogen isothermic adsorption curve and pore distribution of Co ₃ O ₄ powder prepared by post heat treatment in Example 1. FIG.
FIG. 6 is a graph of electrochemical characteristics of Co ₃ O ₄ powder prepared through post-heat treatment in Example 1. FIG.
FIG. 7 is a scanning electron microscope (SEM) photograph of a powder in which Co and C are combined by heat treating the precursor of the hollow structure synthesized in Example 2 in a nitrogen atmosphere. FIG.
8 is a scanning electron microscope (SEM) photograph showing a cross-section of a powder obtained by post-heat-treating a powder having an aggregate structure in Example 2. Fig.
9 is a graph of nitrogen isothermic adsorption curve and pore distribution of the post-heat treated powder in Example 2. FIG.
10 is a scanning electron microscope (SEM) photograph of a precursor synthesized to form an aggregate structure in Example 3, a post-heat treated powder, and a pulverized powder.
11 is a scanning electron microscope (SEM) photograph of the precursor of aggregate structure prepared through the second spray drying process and the powders prepared by post-heat treatment of the powder pulverized in Example 3.
12 is a scanning electron microscope (SEM) photograph showing a cross-section of the agglomerate structure powder post-heat-treated in Example 3. Fig.
13 is a graph showing the electrochemical characteristics of Li (Ni _1/3 Co _1/3 Mn _1/3 ) O ₂ powder of agglomerate structure produced through post heat treatment in Example 3
14 is a scanning electron microscope (SEM) photograph of a precursor powder, a post-heat treated powder, a pulverized powder, and an aggregate structure precursor powder in Example 4;

Hereinafter, the present invention will be described in detail.

In the present invention, a complex liquid phase process requiring a high temperature, a large amount of organic matter and a long reaction time is replaced with a gas phase process in order to synthesize existing nano-sized powders, Which is capable of synthesizing a secondary battery material having a low melting point and a low melting point.

For this purpose, the present invention relates to a process for producing a coagulated powder by performing a spray drying process in two stages, more specifically, through a first spray drying process, a hollow hollow hollow shell having a uniform composition and easy to be crushed The nano-sized powders are heat treated and pulverized to produce nano-sized powders. After the second-order spray-drying process, the pulverized nano-sized powders are agglomerated into agglomerates ( agglomerates powder, preferably an electrode active material powder for a lithium secondary battery.

That is, when grinding a micron-sized powder having a particle shape in the form of particles filled in the body to make the aggregate, it is difficult to uniformly crush the powder with nano-sized powder. In contrast, since the primary powder synthesized through the first spraying process in the present invention is a hollow sphere structure having a thin hollow shell, it can be easily pulverized in the subsequent pulverizing step to obtain a nano-sized powder having a uniform size .

Further, in the conventional electrode active material for a lithium secondary battery, a lithium precursor, a metal precursor, and the like are not mixed with each other, and various phases are present in a complex state, resulting in deterioration of the performance of the battery. Since all constituent components are uniformly mixed from the first step, an electrode active material for a lithium secondary battery having various and uniform compositions can be produced without limitation.

In addition, in the present invention, since various organic materials used in conventional liquid phase processes are not used, it is environmentally friendly and mass productivity and economical efficiency can be improved by applying a vapor phase process simplifying the complexity of the conventional liquid phase process.

In addition, the composition and structure of the composite powder material of the aggregate structure can be easily changed by controlling the composition of the spray solution, and the size of the aggregate powder can be easily controlled by controlling the concentration of the slurry used for agglomeration.

Hereinafter, a method for producing an electrode active material powder for a secondary battery having an aggregate structure made of a nano-sized powder according to the present invention and an electrode active material powder for a secondary battery will be described.

However, the present invention is not limited to the following production methods, and the steps of each process may be modified or selectively mixed if necessary.

In one preferred embodiment of the above process, (a) mixing a precursor containing at least one metal, a chelating agent and a solvent to produce a first spray solution; (b) preparing primary particles in the form of a hollow sphere by first spray drying and heat treatment using the first spray solution; (c) pulverizing the produced primary particles in the form of hollow bodies to prepare ceramic nanoparticles; And (d) second spray-drying the second spraying solution containing the ceramic nanoparticles to form spherical secondary particles in which a plurality of primary particles are assembled with each other to form agglomerated spherical secondary particles .

≪ Method for producing secondary cell powder having agglomerate structure composed of nano powder >

The method of manufacturing the secondary cell powder of the aggregate structure according to the present invention will be described in more detail as follows.

1) Step 1: Preparation of spray solution by mixing metal precursor, chelating agent and solvent

In the synthesis of the electrode active material powder for a lithium secondary battery, the precursor of the components constituting the electrode active material is selected according to the applications such as an anode and a cathode to prepare a spray solution.

The precursor material of the electrode active material for a secondary battery may be a salt of salts such as acetate, nitrate, chloride, hydroxide, or carbonate, which is easily soluble in a solvent such as water or alcohol. An oxide may be used.

In the case where the electrode active material is a cathode active material, the precursor may be a compound containing at least one metal selected from the group consisting of Li, Ni, Co, Mn, Al, V, Fe, P and Cr. When the electrode active material is an anode active material, the precursor may be a compound containing at least one metal selected from the group consisting of Li, Ti, Si, Co, Mn, Zn, Cu, Fe, Mo and Sn. At this time, the precursor compounds described above may be used singly or two or more kinds of them may be used in combination to derive the optimum composition combination.

It is also possible to use oxides of each component, which are inexpensive, by dissolving them in acids such as nitric acid, sulfuric acid, acetic acid and hydrochloric acid. In a specific case, a metal-organic compound-bonded metal organic compound such as titanium tetraisopropoxide (TTIP), tetraethoxyorthosilicate (TEOS) or the like may be used as a precursor material.

The present invention uses a chelating agent to form a primary body in the form of a hollow body. Chelating agents which can be used are compounds having at least one carboxyl group, for example a carboxylic acid, oxalic acid, ethylenediamine acetic acid, citric acid or a mixture of one or more thereof.

The content of the chelating agent is not particularly limited as long as it is in the form of a hollow body, for example, 0.01 to 1 mol based on the total reactants.

The solvent usable in the present invention is not particularly limited as long as it can dissolve the precursor compound easily and can be applied to a vapor phase process such as a spray drying process. For example, distilled water, alcohol, or a mixture thereof can be used.

There is no particular limitation as long as the concentration of the spraying solution formed by dissolving the precursor compound in a solvent can be applied to the spray drying process to form particles of a desired size. At this time, when the concentration of the spraying solution is higher than the saturation solubility, a uniform precursor solution can not be produced, so that it is impossible to synthesize a desired aggregate structure. Therefore, the concentration of the spraying solution in the present invention can be appropriately adjusted within the concentration range in which the solubility of each component constituting the aggregate is allowed, that is, within the saturation solubility. For example, when the concentration is as low as 0.02 mol or less, the productivity of the powder is lowered, which may cause a problem.

2) Second stage: primary spray drying and heat treatment to produce primary particles in the form of hollow bodies

In the second step, the precursor solution (first spraying solution) is injected into a spraying device to generate a droplet uniformly containing the desired composition, and then the droplets are introduced into the reactor to be dried and then heat- Type primary particles are obtained.

Non-limiting examples of usable atomizers include ultrasonic atomizers, first and second atomic air nozzle atomizers, ultrasonic nozzle atomizers, filter expansion droplet generators, (FEAG), a disk type droplet generating device, and the like. Especially, ultrasound and nozzle spraying apparatus are preferable for ultrafine powder synthesis of several micron size (탆) for use in displays and capacitors.

At this time, the average diameter of the droplets according to the present invention is preferably adjusted to a range of 1 to 20 mu m.

The gas for transporting the above-mentioned droplet is not particularly limited. For example, air, oxygen, or the like can be used.

Thereafter, when the droplet is passed through a nozzle together with a hot gas in the spray-drying reactor to undergo drying and bulk expansion, a ceramic hollow ceramic body precursor powder having a thin, thin shell is produced.

Here, the temperature of a conventional carrier gas applied to the first spray drying process is operated at a temperature of 100 DEG C or higher for drying of the constituents and evaporation of water. If the temperature exceeds 400 ° C, there may be a problem in the reactor. Thus, in view of the foregoing, the temperature of the carrier gas according to the present invention may be in the range of 100 ° C or higher, preferably in the range of 100 to 400 ° C.

In nozzles for spraying liquid droplets, the pressure of the nozzle can be used in a commonly used pressure range, but it is difficult to obtain a powder with a thin shell at a pressure of 2 bar or more, and a droplet may not be generated at a pressure of 0.1 bar or less have. Accordingly, the pressure of the nozzle according to the present invention is preferably in the range of 0.1 to 2 bar.

In the present invention, not only the composition of the materials constituting the ceramic powder but also the temperature of the carrier gas, the flow rate of the carrier gas for transporting the droplet, the amount of the droplet to be fed into the reactor, the pressure of the nozzle, The composition of the active material powder for a lithium ion secondary battery to be synthesized can be determined by controlling various variables such as the concentration of the constituent metal components.

After the first spray drying process as described above, a precursor powder having a thin and thin shell is synthesized, and the synthesized ceramic powder passes through a cyclone and is recovered in a glass recovery column.

Then, the hollow precursor powder having a thin shell, which is synthesized by the first spray drying process, is subjected to heat treatment in an atmosphere of air, oxygen, nitrogen, or the like to form a thin, thin shell structure composed of metal components of a desired composition The primary powder of the active material for the ion secondary battery is obtained.

The size of the primary particles after the second step is not particularly limited, but may be, for example, in the range of 1 to 100 mu m in average diameter.

3) Step 3: Formation of nano-size powder by crushing of ceramic powder

In the second step, a ceramic powder having a desired phase of a material is pulverized through a primary spray drying process and a heat treatment to obtain a nano-sized active material powder for a secondary battery.

In this case, the pulverizing process can be used without limitation in the conventional processes known in the art, and can be pulverized together with zirconia balls and distilled water, for example.

Here, the rpm of the pulverizer is not particularly limited, but may be 400 rpm or more, and preferably 400 to 600 rpm, for example. There is no limitation on the milling time, but the milling time according to the present invention may be in the range of 1 hour or more, preferably 1 hour to 6 hours.

The size of the nano-sized powder after the third step is not particularly limited, but may be, for example, an average diameter in the range of 10 to 100 nm.

4) Step 4: Powder production of agglomerate structure by secondary spray drying process of nano-sized powder

The nano-sized ceramic powder obtained through the pulverization process in the third step is subjected to a second spray drying process to produce an aggregate structure powder.

In order to perform the second spray drying process in the present invention, a nano size powder and a solvent are mixed and dispersed to prepare a second spray solution (slurry). At this time, the concentration of the second spraying solution (slurry) is preferably in the range of 10 to 70% by weight of the nanoparticles relative to the solvent, but is not particularly limited thereto.

Here, the temperature of a conventional carrier gas applied to the second spray drying process is operated at a temperature of 300 ° C or less to produce aggregate structure, and it must operate at a temperature of 100 ° C or more for evaporation of water and organic matter. Accordingly, the temperature of the carrier gas in the second spray drying process for obtaining the aggregate structure according to the present invention may be in the range of 100 to 300 ° C.

The inside of the reactor in the fourth step may be air or a nitrogen atmosphere, but is not particularly limited thereto.

The method for preparing an electrode active material powder for a lithium secondary battery according to the present invention may further comprise post-heat treating the particles of the aggregate structure obtained in the range of 300 to 1,000 ° C. in an air atmosphere or a nitrogen atmosphere if necessary It is possible. In the post heat treatment process, the heat treatment atmosphere may be different depending on the kind of the final desired substance. This post-heat treatment causes crystal growth.

After the fourth step, an electrode active material powder for a lithium secondary battery having an aggregate structure is synthesized, and the synthesized aggregate powder is recovered by utilizing a high-temperature bag filter or an electrostatic precipitator.

The size of the final agglomerate powder produced through the above-described process is not particularly limited. For example, the final agglomerate powder may have an average diameter in the range of 1 to 30 mu m, preferably 5 to 20 mu m.

≪ Secondary Battery Electrode Active Material Powder of Aggregate Structure Consisting of Nano-sized Particles >

The present invention provides an agglomerated active material powder for a lithium ion secondary battery comprising nano-sized particles prepared as described above.

The composition of the aggregate structure powder according to the present invention may be any composition used for the lithium ion secondary battery without limitation and may be, for example, a cathode active material or an anode active material.

For example, the cathode active material may be further represented by a compound represented by one of the following general formulas (1) to (11).

???????? Li _x Mn _1-y M _y A ₂ ????? (1)

???????? Li _x Mn _1-y M _y O _{2 -z} X _z ????? (2)

???????? Li _x Mn ₂ O _{4 -z} X _z ????? (3)

???????? Li _x Mn _2-y M _y M ' _z A ₄ ????? (4)

Li _x Ni _1-y M _y A ₂ (5)

Li _x Ni _1-y M _y O _{2 -z} X _z (6)

Li _x Ni _1-y Co _y O _{2 -z} X _z (7)

Li _x Ni _{1- y z} Co _y M _z A _? (8)

Li _x Ni _{1- y z} Co _y M _z O _{2 -?} X _? (9)

Li _x Ni _{1- y z} Mn _y M _z A _? (10)

Li _x Ni _{1- y z} Mn _y M _z O _{2 -?} X _? (11)

In this formula,

0.9? X? 1.1, 0? Y? 0.5, 0? Z? 0.5, 0?

M and M 'are the same as or different from each other and are independently selected from the group consisting of Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, , Sr, V, and rare earth elements,

A is selected from the group consisting of O, F, S and P,

X is selected from the group consisting of F, S and P.

The negative electrode active material may be a metal oxide represented by the following general formula (12), a metal represented by the general formula (13) or an alloy thereof.

[Chemical Formula 12]

M _x O _y

In Formula 12,

M is a metal containing Ti, Co, Mn, Ni, V, Fe, Cu, P, Zr, Mo, Cr or a combination thereof; 0 < x <

 [Chemical Formula 13]

A _z B _a

In Formula 13,

A and B are metals containing Co, Cu, Zn, Ni, Sn or a combination thereof and 0 < z <

The aggregate powder according to the present invention is a spherical secondary particle form in which a plurality of pulverized primary nanoparticles are aggregated with one another. The average diameter may be in the range of 1 to 30 mu m, preferably in the range of 5 mu m to 20 mu m.

Since the aggregate structure powder according to the present invention has excellent electrochemical characteristics, it can be usefully applied to the technical field where such properties are required.

Accordingly, the present invention provides an article comprising a powder for a secondary battery having an aggregate structure made of nano-sized particles manufactured by the above-described method. At this time, the product can be usefully used for cathode material and anode material.

<Electrode for Lithium Secondary Battery and Lithium Secondary Battery>

In addition, the present invention provides an electrode including the electrode active material, and a secondary battery including the electrode, preferably a lithium secondary battery.

The secondary battery of the present invention is not particularly limited except that the electrode active material powder having the aggregate structure described above is used, and can be produced according to a conventional method known in the art. For example, a separation membrane may be inserted between an anode and a cathode, and a nonaqueous electrolyte may be charged.

Here, the secondary battery of the present invention includes a cathode, an anode, a separator, and an electrolyte as a battery component, wherein components of the anode, the cathode, the separator, the electrolyte, and other additives, if necessary, It corresponds to the element of the secondary battery.

The electrode according to the present invention can be manufactured according to a conventional method known in the art. For example, the electrode active material (or negative electrode active material) having the above-described aggregate structure and the binder and, if necessary, the conductive material and the dispersant are mixed and stirred The slurry may be prepared by coating (coating) the slurry on a current collector, compressing the slurry, and then drying the slurry.

In this case, the electrode materials such as dispersion medium, binder, conductive material, current collector and the like can be used as those known in the art, and the content thereof can also be controlled within a usual range.

Also, the non-aqueous electrolyte includes electrolytic components commonly known in the art, such as an electrolyte salt and an electrolyte solvent.

The electrolyte salt is ^{(i) Li +, Na +} , a cation and (ⅱ) selected from the group consisting of _{^{K + PF 6 -, BF 4}} -, Cl -, Br -, I -, ClO 4 -, AsF 6 -, A combination of anions selected from the group consisting of CH ₃ CO ₂ ^- , CF ₃ SO ₃ ^- , N (CF ₃ SO ₂ ) ₂ ^- and C (CF ₂ SO ₂ ) ₃ ^- . Specific examples of the lithium salt include LiClO ₄ , LiCF ₃ SO ₃ , LiPF ₆ , LiBF ₄ , LiAsF ₆ , and LiN (CF ₃ SO ₂ ) ₂ . These electrolyte salts may be used alone or in combination of two or more.

The electrolyte solvent may be selected from cyclic carbonates, linear carbonates, lactones, ethers, esters, acetonitriles, lactams, and ketones.

Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) and fluoroethylene carbonate (FEC). Examples of the linear carbonate include diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), and methyl propyl carbonate (MPC). Examples of the lactone include gamma butyrolactone (GBL), and examples of the ether include dibutyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, and the like. Examples of the ester include methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl pivalate and the like. Examples of the lactam include N-methyl-2-pyrrolidone (NMP), and the ketone is polymethyl vinyl ketone. The halogen derivative of the organic solvent may be used, but is not limited thereto. In addition, the organic solvent may be glyme, diglyme, triglyme, or tetraglyme. These organic solvents may be used alone or in combination of two or more.

The separator may use any porous material that interrupts the internal short circuit of both electrodes and impregnates the electrolyte. Examples thereof include polypropylene-based, polyethylene-based, polyolefin-based porous separation membranes, or composite porous separation membranes in which an inorganic material is added to the above-mentioned porous separation membranes.

Hereinafter, the present invention will be described in more detail with reference to the following examples. It should be understood that these examples are for the purpose of illustrating the present invention more specifically, and the scope of the present invention is not limited to these examples. It will be apparent to those skilled in the art that the present invention is not limited thereto.

Example 1: Secondary battery powder synthesis of single component type aggregate structure

A positive electrode material and negative electrode material aims to synthesize all of the secondary battery in a variety of material composition was prepared using the material of the Co ₃ O ₄ nanoparticles of the aggregate structure consisting of Co ₃ O _4.

Powders of Co ₃ O ₄ agglomerate structure were synthesized by spray drying under various manufacturing conditions by varying the temperature of the carrier gas transporting the droplets, the concentration of the spraying solution, the flow rate of the carrier gas, and the addition of organic matter.

As a raw material of the Co component, Co nitrate was used. Citric acid was used as a chelating agent. The total concentration of the total solution of the precursor containing cobalt and citric acid was 0.5M. As the droplet generating device, droplets of various sizes are generated and nozzles which are easy to mass produce are used.

The first ceramic powder synthesized by the first spray drying process had a hollow sphere structure with a thin hollow shell. The synthesized Co ₃ O ₄ powder was oxidized in a box furnace maintained at 200 ° C. for 3 hours to finally produce a hollow hollow structure having a Co ₃ O ₄ phase.

1 is a scanning electron microscope (SEM) and a transmission electron microscope (TEM) photograph of a Co ₃ O ₄ precursor powder having a hollow hollow structure synthesized by a first spray drying process and a powder obtained through heat treatment, and X Ray diffraction pattern.

Referring to FIG. 1 (a), all of the synthesized powders had a size of several tens of microsamples and had a thin shell. FIG. 1 (b) shows a scanning electron microscope (SEM) image of the powder obtained by heat-treating the Co ₃ O ₄ precursor powder obtained in the spray drying process. Fig. 1 (c) shows an X-ray diffraction pattern of the powders obtained in Figs. 1 (a) and 1 (b). The precursor powder of Co ₃ O ₄ obtained by the spray drying process shown in FIG. 1 (a) was amorphous, but it was found that the powder of FIG. 1 (b) after heat treatment obtained a pure Co ₃ O ₄ phase .

2 is a scanning electron microscope (SEM) image and a transmission electron microscope (SEM) image of a nano-sized powder obtained by pulverizing Co ₃ O ₄ powder subjected to heat treatment.

2 (a) and 2 (b) are scanning electron microscope (SEM) and transmission electron microscope (TEM) photographs, respectively. According to FIG. 2 (b), it was found that the nano-sized powder obtained through the pulverization process had an average size of 10 nm.

FIG. 3 is a scanning electron microscope and cross-sectional photographs of a secondary powder having an agglomerate structure obtained through a second spray drying process of a nano-sized powder obtained through pulverization. 3 (a) and 3 (b) are respectively a scanning electron microscope and a sectional photograph.

As can be seen from the scanning electron microscope (SEM) photograph of FIG. 3 (a), the size is 1 to 2 μm in size, and 8 to 10 μm in size. On the other hand, FIG. 3 (b) shows that the secondary powder of the agglomerate structure obtained through the spraying process forms a agglomerates structure with a powder of several nanometers in size.

FIG. 4 shows a scanning electron microscopic photograph of powders obtained by varying the heat treatment temperature of the Co ₃ O ₄ powder having the aggregate structure.

4 (a) shows the Co ₃ O ₄ powder of the aggregate structure is heat-treated at 200 ° C, FIG. 4 (b) shows 400 ° C, FIG. 4 (SEM) photographs of the powders heat-treated in each case.

FIG. 5 shows the nitrogen isotherm adsorption curve and pore size distribution of the Co ₃ O ₄ powder obtained through post-heat treatment. Due to the large number of pores in the aggregate structure, it had a large specific surface area of 5.94 m ² g ^-1 and fine pores of 18 nm.

FIG. 6 is a graph of electrochemical characteristics of Co ₃ O ₄ powder obtained through post-heat treatment. Showed high capacity and stable cycle characteristics even at a current density of 1400 mA / g.

Example 2: Aggregate structure of single component system and carbon composite powder Synthesis of powder

The composite material containing carbon in the same composition as in Example 1 was synthesized into a flocculated structure by post-heat treatment in a nitrogen atmosphere instead of post-heat treatment in the same manner as in Example 1 above.

When the heat treatment is performed in an air atmosphere, the materials used as the chelating agent are all burnt to remain in the final powder. However, when the heat treatment is performed in a nitrogen atmosphere, the material used as the chelating agent is decomposed into carbon and remains in the final powder do.

7 is a scanning electron microscope (SEM) image of powders in which Co and C are mixed with each other by heat treating the precursor of the hollow structure in a nitrogen atmosphere.

7 (a), 7 (b), 7 (c), and 7 (d) are graphs showing the results of a scanning electron microscope (SEM) of powders obtained by heat-treating powders of precursors, heat-treated nitrogen, powders of aggregated structure, It is a microscope (SEM) photograph.

8 is a scanning electron microscope (SEM) photograph showing a cross section of a powder obtained by heat-treating a powder having an aggregate structure.

FIG. 8 (a) is a low magnification image, and FIG. 8 (b) is a scanning electron microscope (SEM) photograph of a high magnification, showing that nano-sized particles are filled with carbon.

9 shows the nitrogen isotherm adsorption curve and pore size distribution of the powder obtained through the post-heat treatment. Due to the large number of pores in the aggregate structure, it had a large specific surface area of 45 m ² g ^-1 and fine pores of 21 nm.

Example 3: Secondary cell powder synthesis of multicomponent aggregate structure

Under the same manufacturing conditions as in Example 1, a Li (Ni _1/3 Co _1/3 Mn _1/3 ) O ₂ cathode material was synthesized as an agglomerate structure.

More specifically, Li nitrate, Ni nitrate, Co nitrate and Mn nitrate were used as raw materials for Li, Ni, Co and Mn components. Citric acid was used as a chelating agent. The total concentration of the total solution of lithium, nickel, cobalt, manganese and citric acid in the precursor was 0.5M. As the droplet generating device, droplets of various sizes are generated and nozzles which are easy to mass produce are used.

FIG. 10 is a scanning electron microscope (SEM) photograph of a precursor synthesized to form a coagulated structure, a powder after heat treatment, and a powder obtained by pulverizing the heat-treated powder.

10 (a) is a Li-Ni-Co-Mn-O precursor powder having a hollow structure with a thin hollow shell synthesized through a first spray drying process. Referring to FIG. 10 (b) And the nano-sized particles are connected to each other. 10 (c) is a scanning electron microscope (SEM) image of a nano-sized powder obtained by pulverizing powder of a hollow structure composed of nano-sized particles. It was found that the powder was a nanometer sized powder which can not be measured by a scanning electron microscope photograph.

11 is a scanning electron microscope (SEM) photograph of the precursor of the aggregate structure obtained through the second spray drying process and the powders obtained by heat treatment of the nano-sized powder.

11 (a) is a precursor of the aggregate structure after the second spray drying process, FIG. 11 (b) is a heat treatment at 800 ° C., FIG. 11 (c) is heat treatment at 900 ° C., SEM photographs of the obtained powders.

12 is a scanning electron microscope (SEM) image of a cross-section of a powder of aggregate structure.

12 (a) and 12 (b) are scanning electron micrographs of a low magnification and a high magnification, respectively. As shown in FIG. 12, all of the aggregate structure powders were filled.

13 is a graph showing electrochemical characteristics of Li (Ni _1/3 Co _1/3 Mn _1/3 ) O ₂ powder obtained through post-heat treatment. FIG. 13 shows that the device exhibited high capacity and stable characteristics even at a high current density.

Example 4: Powder synthesis of multi-component complex agglomerate structure

Li ₂ MnO ₃ --Li (Ni _1/3 Co _1/3 Mn _1/3 ) O ₂ cathode material was synthesized as an agglomerate structure under the same production conditions as in Example 1 above.

14 is an SEM micrograph of a precursor powder, a heat-treated powder, a pulverized powder, and an aggregate structure precursor powder of a multicomponent composite. Unlike Example 3 having a single phase, in Example 4, a composite powder in which two phases of Li ₂ MnO ₃ and Li (Ni _1/3 Co _1/3 Mn _1/3 ) O ₂ are present in a complex and uniform state Were synthesized.

Claims (16)

(a) mixing a precursor containing at least one metal, a chelating agent and a solvent to produce a first spray solution;
(b) primary spray drying and heat treatment using the first spray solution to prepare primary particles in the form of a hollow body;
(c) pulverizing the produced primary particles in the form of hollow bodies to prepare nanoparticles; And
(d) spray-drying the second spraying solution containing the nanoparticles to form spherical secondary particles in which a plurality of primary nanoparticles are aggregated with each other to form agglomerated spherical secondary particles
Wherein the electrode active material powder for a lithium secondary battery comprises: The method of claim 1, wherein the precursor of step (a) is selected from the group consisting of acetate, nitrate, chloride, hydroxide, carbonate, and oxide containing metal. Wherein the electrode active material powder for lithium secondary batteries is at least one selected from the group consisting of lithium, The method according to claim 1, wherein when the electrode active material is a cathode active material, the precursor includes at least one metal selected from the group consisting of Li, Ni, Co, Mn, Al, V, Fe, Wherein the electrode active material powder for lithium secondary battery is a lithium secondary battery. The method according to claim 1, wherein when the electrode active material is an anode active material, the precursor includes at least one metal selected from the group consisting of Li, Ti, Si, Co, Mn, Zn, Cu, Fe, Wherein the electrode active material powder for lithium secondary battery is a lithium secondary battery. 2. The electrode active material powder for a lithium secondary battery according to claim 1, wherein the chelating agent is selected from the group consisting of carboxylic acid having at least one carboxyl group, oxalic acid, ethylenediamine acetic acid, citric acid, and combinations thereof. Way. The method according to claim 1, wherein the step (b) comprises injecting the first spraying solution into a spraying device to generate droplets, and then injecting droplets formed into the reactor to dry the electrode active material powder for a lithium secondary battery. 7. The method of claim 6, wherein in step (b), the atomizing device is selected from the group consisting of an ultrasonic atomizing device, a first-body air nozzle atomizing device, an air body nozzle nozzle atomizing device, an ultrasonic nozzle atomizing device, a filter expansion droplet generating device Wherein the electrode active material powder is selected from the group consisting of a droplet generating device and a droplet generating device. The method of claim 1, wherein the first spray drying temperature in step (b) is in the range of from 100 to 400 캜,
Wherein the heat treatment temperature is in a range of 200 to 500 &lt; RTI ID = 0.0 &gt; C. &Lt; / RTI &gt; The method according to claim 1, wherein the crushing rate in the step (c) ranges from 400 to 600 rpm. The method according to claim 1, wherein the concentration of the second spraying solution in the step (d) ranges from 10 to 70% by weight of the nanoparticles relative to the solvent. The method for producing an electrode active material powder for a lithium secondary battery according to claim 1, further comprising post-heat-treating the secondary particles formed in the step (d) in an air atmosphere or a nitrogen atmosphere at 300 to 1,000 ° C . 12. An electrode active material powder for a lithium secondary battery, produced by the method according to any one of claims 1 to 11, comprising spherical secondary particles in which a plurality of primary nanoparticles are assembled and aggregated. The electrode active material powder for a lithium secondary battery according to claim 12, which is a cathode active material selected from the group of compounds represented by the following Chemical Formulas 1 to 11:
???????? Li _x Mn _1-y M _y A ₂ ????? (1)
???????? Li _x Mn _1-y M _y O _{2 -z} X _z ????? (2)
???????? Li _x Mn ₂ O _{4 -z} X _z ????? (3)
???????? Li _x Mn _2-y M _y M ' _z A ₄ ????? (4)
Li _x Ni _1-y M _y A ₂ (5)
Li _x Ni _1-y M _y O _{2 -z} X _z (6)
Li _x Ni _1-y Co _y O _{2 -z} X _z (7)
Li _x Ni _{1- y z} Co _y M _z A _? (8)
Li _x Ni _{1- y z} Co _y M _z O _{2 -?} X _? (9)
Li _x Ni _{1- y z} Mn _y M _z A _? (10)
Li _x Ni _{1- y z} Mn _y M _z O _{2 -?} X _? (11)
In this formula,
0.9? X? 1.1, 0? Y? 0.5, 0? Z? 0.5, 0?
M and M 'are the same as or different from each other and are independently selected from the group consisting of Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, , Sr, V, and rare earth elements,
A is selected from the group consisting of O, F, S and P,
X is selected from the group consisting of F, S and P. The electrode active material powder for a lithium secondary battery according to claim 12, which is a metal oxide represented by the following formula (12) or a metal or alloy negative electrode active material represented by the following formula (13).
[Chemical Formula 12]
M _x O _y
In Formula 12,
M is a metal containing Ti, Co, Mn, Ni, V, Fe, Cu, P, Zr, Mo, Cr or a combination thereof; 0 < x <
[Chemical Formula 13]
A _z B _a
In Formula 13,
A and B are metals containing Co, Cu, Zn, Ni, Sn or a combination thereof and 0 < z < The electrode active material powder for a lithium secondary battery according to claim 12, wherein the electrode active material powder for a lithium secondary battery is in the form of spherical microparticles having an average diameter ranging from 1 m to 30 m. A lithium ion secondary battery comprising the electrode active material powder of claim 12.

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