KR20190076767A - Manufacturing method of a positive electrode active material for rechargeable battery, positive electrode active material for rechargeable battery manufacture using the same, and rechargeable battery including the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a positive electrode active material for a rechargeable battery with improved productivity while securing excellent lifespan properties of a lithium rechargeable battery, a positive electrode active material for a rechargeable battery manufactured by using the same and a rechargeable battery including the same. The method for manufacturing a positive electrode active material for a rechargeable battery comprises the following steps of: mixing a metal oxide, a lithium compound and a binder to prepare a mixture; inputting the mixture to a molded article preparing device and preparing a molded article; and filling the molded article into a sintering container to perform sintering. The molded article has an aspect ratio (major axis / minor axis) of 0.3 to 1.0 and the moisture content of 0.5 to 9 wt%.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a cathode active material for a secondary battery, a cathode active material for a secondary battery manufactured using the same, and a secondary battery comprising the cathode active material for the secondary battery. BACKGROUND ART < RTI ID = 0.0 > BATTERY INCLUDING THE SAME}

The present invention relates to a method for producing a cathode active material for a secondary battery, a cathode active material for a secondary battery manufactured using the same, and a secondary battery comprising the cathode active material. More particularly, the present invention relates to a method for manufacturing a cathode active material for a secondary battery, And a method of manufacturing a positive electrode active material for a battery.

Lithium secondary batteries are widely used as energy storage devices for various devices as their application fields are expanded. Accordingly, in order to improve the energy density of a lithium secondary battery, development of a high-capacity electrode active material has been progressed.

Generally, a lithium secondary battery is manufactured by using a material capable of reversible intercalation / deintercalation of lithium ions as a cathode active material and an anode active material, and charging an electrolyte between the anode and the cathode including the cathode active material and the anode active material.

As the cathode active material of the lithium secondary battery, a lithium composite metal compound or the like is used. Such a cathode active material can be produced by calcining a powdery raw material at a high temperature.

In the process of producing the cathode active material, the firing is performed in an atmosphere of air containing oxygen. At this time, the firing atmosphere gas must be easily circulated so that the raw material and oxygen can be easily contacted to improve the firing efficiency .

Accordingly, various attempts have been made to improve the firing efficiency and to improve the productivity of the cathode active material manufacturing process.

The present embodiments provide a method for producing a positive electrode active material for a lithium secondary battery having improved productivity while securing excellent lifetime characteristics of the lithium secondary battery, a positive electrode active material produced thereby, and a secondary battery comprising the same.

A method of preparing a cathode active material for a lithium secondary battery according to an embodiment of the present invention includes the steps of: preparing a mixture by mixing a metal hydroxide, a lithium compound, and a binder; injecting the mixture into a molding machine to produce a molded body; (Long axis / short axis) in the range of 0.3 to 1.0 and a water content in the range of 0.5 to 9% by weight.

In addition, the present invention may include a cathode active material for a lithium secondary battery manufactured by the above-described production method.

The lithium secondary battery according to an embodiment of the present invention may include a cathode, a cathode, and an electrolyte including the cathode active material for the lithium secondary battery.

The method for producing a cathode active material for a lithium secondary battery according to an embodiment of the present invention is excellent in process productivity using a molded body manufacturing machine because a molded body is manufactured so that an aspect ratio and a moisture content satisfy a specific range.

In addition, since the carbonaceous material produced in the firing process can be easily discharged, the amount of the raw material that can be loaded in the firing vessel can be significantly increased, thereby ensuring excellent productivity in the production of the cathode active material have.

In addition, the lithium secondary battery including the cathode active material produced by the above-mentioned method can secure excellent lifetime characteristics.

FIG. 1 illustrates an example of a molded body manufactured according to a method of manufacturing a cathode active material for a secondary battery according to an embodiment.
2A is a plan view of yz in Fig.
2B is a cross-sectional view taken along the line xz in FIG.
3 illustrates another example of a molded body manufactured according to the method for manufacturing a cathode active material for a secondary battery according to an embodiment.
Fig. 4 shows a state in which the molded body of Fig. 3 is mounted on an inner fire wall.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In addition, since the sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings.

Also, throughout the specification, when an element is referred to as "including" an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Hereinafter, a method of manufacturing a cathode active material for a secondary battery according to an embodiment of the present invention will be described in detail.

A method of manufacturing a cathode active material for a secondary battery according to one embodiment includes the steps of preparing a mixture by mixing a metal hydroxide, a lithium source, and a binder, adding the mixture to a molding machine to produce a molded body, And firing the mixture.

At this time, the molded article has an aspect ratio (major axis / minor axis) of 0.3 to 1.0 and a water content of 0.5 to 9 wt%.

Specifically, the aspect ratio of the molded article, that is, the major axis / minor axis value may range from 0.3 to 1.0, or from 0.5 to 0.8. When the aspect ratio of the molded article satisfies the above range, the molded article has excellent strength and can maintain the shape of the molded article during the transfer process.

The water content of the shaped body may also be, for example, in the range of 0.5 wt% to 9 wt%, more specifically 1 wt% to 8 wt% or 1 wt% to 7 wt%. If the water content of the molded product is less than 0.5% by weight, the aggregation of the mixture is not achieved and the molded product is difficult to produce. In addition, when the water content exceeds 9% by weight, it is difficult to produce a molded body in a desired shape, and the mixture adheres to the molded body manufacturing machine in the molding process.

In the present specification, the moisture content can be measured by putting the produced molded body into a moisture content measuring apparatus and comparing the weights before and after the moisture is evaporated.

FIG. 1 illustrates an example of a molded body manufactured according to a method of manufacturing a cathode active material for a secondary battery according to an embodiment. FIG. 2a is a plan view of FIG. 1, and FIG. 2b is a sectional view of FIG.

Referring to FIG. 1, the molded body manufactured in the molding step of this embodiment may be in the form of a briquette as shown in FIG.

Further, referring to Figs. 2A and 2B, the edge R can be represented by R1 in Fig. 2A and R2 in Fig. 2B.

The molded body indicated by R1 and R2 in Figs. 2A and 2B, respectively, may have an R size of the edge of 1.0 mm or more, more specifically, 1.0 mm to 20 mm or 1.0 mm to 8.0 mm. If the R size of the edge of the formed article is less than 1.0 mm, the formed article may be damaged in the process of charging the formed article into the sintered container in the firing step to be described later. Accordingly, there is a problem in that the amount of residual lithium on the surface of the finally prepared cathode active material increases due to insufficient flow of air such as oxygen during firing.

FIG. 3 illustrates another example of a molded body manufactured according to the method of manufacturing a cathode active material according to an embodiment, that is, a spherical molded body. Referring to FIG. 3, the formed body 100 may include a precursor 10 and lithium carbonate 20.

Therefore, the shape of the molded body is not limited to the brittle shape shown in FIG. 1, but may be spherical or elliptical, as shown in FIG. 3, or may be a mixture thereof.

At this time, the average long diameter of the molded body, that is, the average longest diameter of the molded body may be in the range of 5 mm to 100 mm or 40 to 60 mm. When the average long diameter of the formed body is less than 5 mm, the size of the voids formed in the molded body is small, and the gas can not flow smoothly. Further, when the average long diameter of the molded product exceeds 100 mm, the molded product is deformed in the sintering process, and the contact area between the sintered container and the molded product is increased, thereby decreasing the service life of the sintered container.

That is, the formed body according to the present embodiment is manufactured to have a large size of 500 times or more of the particle size such as a metal hydroxide or a lithium compound, thereby forming voids in the formed body, filling the body with the calcined vessel, Can be performed.

Oxygen required for the reaction can be easily introduced through the pores to increase the firing efficiency, and the reaction by-products can smoothly discharge the water vapor and the carbon dioxide from the firing vessel.

Next, the density of the formed body may be in the range of 1.5 g / cc to 3.0 g / cc, or 2.0 g / cc to 2.8 g / cc.

When the density of the molded body is less than 1.5 g / cc, the amount of the raw material filled per unit firing vessel is not significantly different from the case where the metal hydroxide and the powder of the lithium compound are fired without producing the molded body, There is a problem. In addition, when the density of the molded body is 3.0 g / cc or more, the discharge of carbon dioxide and steam generated in the molded body in the firing step is not smooth, resulting in a problem that the capacity per unit weight of the cathode active material for lithium secondary batteries decreases.

By manufacturing the molded body with high density in this manner, the amount of powder loaded per unit firing vessel in the firing step can be remarkably increased, and productivity can be improved remarkably.

Hereinafter, each step of the method of manufacturing the cathode active material for a secondary battery according to the present embodiment will be described in more detail.

First, the step of mixing a metal hydroxide, a lithium raw material and a binder to prepare a mixture will be described.

The mixture can be produced by, for example, mixing a metal hydroxide, a lithium compound and a binder into a mixer and mixing.

At this time, as the mixer, for example, a granulator or an intensive mixer may be used.

The metal hydroxide used in the production of the molded article of the present embodiment is a secondary particle having an average particle diameter of 10 to 20 占 퐉 in the form of aggregated primary particles of 1 占 퐉 or less.

Here, the metal hydroxide may include a compound represented by the following formula (1) or (2).

[Chemical Formula 1]

M 1 _x M 2 _y M 3 _z (OH) _{2 + δ}

M1, M2 and M3 are selected from the group consisting of Ni, Co, Mn and combinations thereof, and 0? X? 1, 0? Y? 1, 0? Z? ? 1, 0.0????? 0.02, 0 <x + y + z?

(2)

M 1 _x M 2 _y M 3 _z (OH) _{2 + δ}

M1, M2 and M3 are selected from the group consisting of Ni, Co, Al and combinations thereof, 0.8?? X?? 1, 0? Y? 0.2, 0? Z? ? 0.2, 0.0????? 0.02, and 0 <x + y + z?

Such a metal hydroxide can be produced by a conventional method known in the art and is not particularly limited. For example, the metal hydroxide can be produced by a solid phase reaction method, coprecipitation method, sol-gel method, hydrothermal synthesis method or the like.

The amount of the metal hydroxide to be added may be in the range of 67 to 72% by weight based on the entire mixture, and may be in the range of 67 to 70% by weight.

In the lithium compound used for the production of the porous structure, the lithium carbonate or lithium hydroxide is a secondary particle having an average particle diameter of several micrometers in the form of aggregated primary particles of 1 탆 or less, for example, lithium carbonate or hydroxide Lithium.

The amount of the lithium compound to be added may range from 28% by weight to 33% by weight, specifically from 28% by weight to 30% by weight, based on the whole mixture.

On the other hand, the binder serves to bind metal hydroxide and lithium compound, and may include, for example, water. At this time, the amount of the binder to be added may be 0.5 wt% to 9 wt%. If the content of the water-containing binder is less than 0.5% by weight, binding of the molded article is difficult. When the content of the binder containing water is more than 9% by weight, the viscosity of the mixture of the metal hydroxide, the lithium compound and the binder is lowered, making it difficult to produce a molded article in a desired shape.

The binder may further include at least one of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) in addition to water.

The content of at least one of the polyvinyl alcohol (PVA) and the polyvinyl pyrrolidone (PVP) may range from 0% to 1% by weight based on the mixture of the metal hydroxide and the lithium compound have. These binders help the binder in the process of producing the molded article but are burned in the baking process. Therefore, when an excessive amount of the binder is added, carbon dioxide is generated in a large amount during the firing process, and the residual lithium carbonate concentration on the surface of the cathode active material may increase, so that the content of the binder preferably satisfies the above range.

On the other hand, the mixture of the metal hydroxide, the lithium compound and the binder may further contain additives as required.

The additive may be at least one selected from the group consisting of, for example, oxides or hydroxides of at least one of Zr, Ti, W, Al, Mg, V, Co and Ni, nitrates and combinations thereof. It is not. In this embodiment, the additive may include Zr (OH) ₄ , which may be contained in an amount ranging from 0.01% by weight to 1% by weight based on the entire mixture of the metal hydroxide and the lithium compound. The additive can improve the stability by substituting the metal ion of the cathode active material and acts as an oxide form on the surface of the cathode active material to prevent the reaction with the electrolyte solution.

Next, the mixture is introduced into a molding machine to produce a molded article.

At this time, as the molded body producing machine, for example, at least one of a briquetting machine and a granulator may be used. It is extremely advantageous in that the productivity of the molded article can be further improved when the molded body according to the present embodiment is molded using a briquetting machine.

The production process of the molded body can be carried out, for example, for 0.3 to 2 seconds at a pressure range of 10 to 100 MPa using a briquetting machine.

Thereafter, a step of filling the formed body with the fired body and firing is performed.

Specifically, the firing step may include a step of loading the molded body into a firing vessel, disposing a firing vessel in the firing furnace, and supplying at least one of an oxygen-containing gas and an inert gas to the firing furnace and firing .

That is, firing may be performed by, for example, performing an oxygen-containing gas or an inert gas atmosphere at a temperature of 400 to 1100 for 10 to 30 hours, but is not limited thereto. The temperature and time of firing may be appropriately changed as necessary.

As the firing container, for example, alumina, mullite, or a material having a coating layer formed thereon can be used, and any material that is inert to the raw material and has durability under the firing temperature can be used without limitation.

Further, the firing container to be disposed in the firing furnace, for example, the firing chamber may be one, or two or more firing containers may be stacked and fired in two or more layers.

Thereafter, after the firing step, the fired compact is cooled and pulverized.

The cooling and pulverization can be carried out by a conventional method known in the art and are not particularly limited.

The cooling can be carried out at a cooling rate of, for example, 1 / min to 10 / min from a firing temperature to at least 200. The cooled compact is pulverized to obtain a cathode active material for a secondary battery according to this embodiment.

In the process for producing the cathode active material for a secondary battery, the firing process is performed by supplying at least one of an oxygen-containing gas and an inert gas as described above. At this time, the oxygen-containing gas flowing from the outside must be easily circulated in the firing container, for example, the fire-resistant container. In this case, the raw material filled in the firing vessel is in contact with oxygen, and the firing efficiency can be improved.

In the firing process, steam and carbon dioxide, which are reaction byproducts, are generated. Among these byproducts, carbon dioxide is heavier than the oxygen-containing gas used for controlling the firing atmosphere, and thus remains in the firing vessel and reacts with the lithium oxide on the surface of the cathode active material during the cooling process to form lithium carbonate.

However, if the concentration of lithium carbonate on the surface of the cathode active material increases, the dispersibility of the cathode active material in slurry production may deteriorate. In addition, when such a cathode active material is applied to a lithium secondary battery, there is a problem in that the capacity of the battery is reduced to deteriorate the life characteristics. Therefore, it is necessary to smoothly discharge the carbon dioxide generated during the firing process.

To this end, the present invention has developed a method for producing a molded body having an aspect ratio and a water content satisfying a specific range as described above, and then putting the mixture into a firing step to prepare a cathode active material for a lithium secondary battery. In this case, the productivity of the molded body manufacturing process is improved, and voids are formed inside the molded body. Through these pores, the flow of oxygen can be smoothly performed, the firing efficiency can be increased, and the carbon dioxide generated in the firing process can be easily discharged. As a result, the amount of powder that can be filled per unit firing vessel in the firing process can be increased, and productivity is also significantly improved.

The cathode active material prepared according to one embodiment of the present invention can be usefully used for the anode of a lithium secondary battery. The lithium secondary battery includes a cathode and an electrolyte including a cathode active material prepared by the above-described method together with a cathode.

Specifically, the lithium secondary battery according to an embodiment of the present invention may include an electrode assembly including a cathode, a cathode, and a separator disposed between the anode and the cathode.

The negative electrode may be prepared by preparing a composition for forming a negative electrode active material layer by mixing a negative electrode active material, a binder and a conductive material, and then applying the composition to an anode current collector such as copper.

As the negative electrode active material, a material capable of intercalating / deintercalating lithium is used. Examples of the negative active material include lithium metal, lithium alloy, coke, artificial graphite, natural graphite, Lt; / RTI &gt;

Examples of the binder include polyvinyl alcohol, carboxymethylcellulose / styrene-butadiene rubber, hydroxypropylene cellulose, diacetylene cellulose, polyvinyl chloride, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene Polypropylene and the like can be used, but the present invention is not limited thereto. The binder may be mixed in an amount of 1 to 30% by weight based on the total amount of the composition for forming the negative electrode active material layer.

The conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and specifically includes graphite such as natural graphite and artificial graphite; Carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used. The conductive material may be mixed in an amount of 0.1 to 30% by weight based on the total amount of the composition for forming the anode active material layer.

The anode includes the cathode active material prepared by the method for producing a cathode active material according to an embodiment. That is, the cathode active material, the binder and optionally the conductive material may be mixed to prepare a composition for forming a cathode active material layer, and then the composition may be applied to a cathode current collector such as aluminum. Further, the conductive material, binder and solvent are used in the same manner as in the case of the above-mentioned anode.

As the electrolyte to be filled in the lithium secondary battery, a non-aqueous electrolyte or a known solid electrolyte may be used, and a lithium salt dissolved therein may be used.

The lithium salt may be, for example, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiSbF ₆ , LiAlO ₄ , LiAlCl ₄ , LiCl, and LiI may be used.

Examples of the solvent of the non-aqueous electrolyte include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate; Chain carbonates such as dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate; Esters such as methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate and? -Butyrolactone; Ethers such as 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane and 2-methyltetrahydrofuran; Nitriles such as acetonitrile; Amides such as dimethylformamide, and the like can be used, but the present invention is not limited thereto. These may be used singly or in combination. Particularly, a mixed solvent of cyclic carbonate and chain carbonate can be preferably used.

As the electrolyte, a gelated polymer electrolyte in which an electrolyte solution is impregnated with a polymer electrolyte such as polyethylene oxide or polyacrylonitrile, or an inorganic solid electrolyte such as LiI or Li ₃ N can be used.

The separator may be an olefin-based polymer such as polypropylene, which is chemically resistant and hydrophobic; A sheet or a nonwoven fabric made of glass fiber, polyethylene or the like can be used. When a solid electrolyte such as a polymer is used as the electrolytic solution, the solid electrolytic solution may also serve as a separation membrane.

Hereinafter, the present invention will be described in more detail with reference to experimental examples. These experimental examples are only for illustrating the present invention, and the present invention is not limited thereto.

Example  One

(1) Preparation of cathode active material

Ni ₀ as metal hydroxide _{. 6} Co _{0 . 2 Mn 0 .2 (OH) 2} , a mixture was prepared by the Li ₂ CO ₃ and water, the lithium raw material input to the mixer.

The mixture was poured into a briquetting machine to prepare a shaped body. The produced molded article had an aspect ratio (long axis / short axis) of 0.6, a water content of 6% by weight, and an average long diameter of 50 mm.

The molded body was filled in a saggar of mullite material, and then fired at 900 DEG C in a sintering furnace in an air atmosphere. A state in which the molded article is loaded in the firing container is shown in Fig. The amounts of the filled bodies are shown in Table 1 below.

The sintered material was pulverized and classified according to the firing to prepare a cathode active material for a lithium secondary battery.

(2) Production of secondary battery

The positive electrode active material for a lithium secondary battery prepared in (1) above, 2 wt% of a conductive material (Denka Black), 2 wt% of a binder (PVDF) and 1 wt% of a thickener (CMC) (NMP) solvent to prepare a slurry.

The slurry was uniformly applied to an aluminum (Al) current collector, compressed by a roll press, and vacuum-dried in a 100 ° C vacuum oven for 12 hours to prepare a positive electrode.

Lithium metal (Li-metal) was used as a counter electrode, and a mixed solvent of ethylene carbonate (EC: Ethylene Carbonate): dimethyl carbonate (DMC, Dimethyl Carbonate) ₆ solution was used.

Using each of the above components, a 2032 half-coin cell was fabricated according to a conventional manufacturing method.

Comparative Example  One

A precursor of the metal hydroxide form including nickel, cobalt, and manganese was prepared by coprecipitation.

A half cell was prepared in the same manner as in Example 1, except that Li ₂ CO ₃ , which is a lithium source material, was prepared and uniformly mixed with the precursor to fill the saggar.

At this time, the fill amount of the mixture filled in the inner wall is shown in Table 1 below.

Comparative Example  2

Ni ₀ as metal hydroxide _{. 6} Co _{0 . 2 Mn 0 .2 (OH) 2} , a mixture was prepared by the Li ₂ CO ₃ and water, the lithium raw material input to the mixer.

At this time, water was added so as to be 15% by weight based on the total weight of the mixture.

The mixture was introduced into a briquetting machine to prepare a molded article.

However, since the formed body did not fall off well in the briquetting machine, it was difficult to measure the aspect ratio, and thus it was difficult to carry out the firing process.

Experimental Example  1 - Residue on the surface of the cathode active material Lithium sheep  Measure

The residual lithium content on the surface of the cathode active material prepared according to Example 1 and Comparative Example 1 was measured by acid-base titration using dilute hydrochloric acid (HCl). The results are shown in Table 1 below.

Experimental Example  2 - Evaluation of life characteristics

The lifetime characteristics of the half-cells produced according to Example 1 and Comparative Example 1 were evaluated.

First, charging and discharging were performed at 0.1 C in a range of 2.5 V to 4.25 V at 25 캜 using a charge / discharge device (Maccor) to which a constant current was applied. The initial discharge capacity and initial charge / discharge efficiency were shown in Table 1 below . The same method was repeated 50 times to calculate the discharge capacity ratio at 50 times to one discharge capacity to determine the capacity retention rate, which was defined as the cycle life.

division Example 1 Comparative Example 1 Amount of fill per unit (kg) 6 3 Residual LiOH (ppm) on the cathode active material surface 700 1000 Residual Li ₂ CO ₃ (ppm) on the cathode active material surface 1500 3500 Initial discharge capacity (mA / g, @ 0.1C) 176 173 Initial Charge / Discharge Efficiency (%) 91 88 Capacity retention rate (%) (50 ^th / 1 ^st @ 1C) 98 96

The results are shown in Table 1. Referring to Table 1, in the case of the cathode active material produced according to Example 1 in which a molded body having the same characteristics as those of this embodiment was manufactured and fired, as compared with Comparative Example 1 in which the powder was fired without producing a molded body, It can be seen that the amount of lithium hydroxide and lithium carbonate remaining in the electrolyte solution is reduced by 30% or more. Therefore, it can be confirmed that when the cathode active material is manufactured after the sintered body having a specific aspect ratio and moisture content as in the present embodiment is manufactured, the effect of reducing the residual lithium content on the surface of the active material is excellent.

As a result, it can be confirmed that the lithium secondary battery including the cathode active material prepared in the same manner as in Example 1 does not deteriorate the lifetime characteristics and has excellent lifetime characteristics.

However, even when a molded article is produced, when the water content is high and the water content of the mixture of the metal hydroxide and the lithium compound is high, it is difficult to produce the molded article properly.

In addition, in the case of Example 1, it can be confirmed that the amount of charge per unit in the unit is doubled as compared with Comparative Example 1. [

Therefore, when the cathode active material is manufactured according to an embodiment of the present invention, the residual lithium content of the surface can be reduced, and the amount of the raw material that can be filled per unit firing vessel can be increased The productivity can be remarkably improved.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: molded article
10: precursor
20: Lithium carbonate

Claims (16)

Mixing a metal hydroxide, a lithium compound and a binder to prepare a mixture;
Adding the mixture to a molding machine to produce a molded body; And
Filling the molded body into a firing vessel and firing the firing vessel;
Lt; / RTI &gt;
Wherein the shaped body has an aspect ratio (major axis / minor axis) in the range of 0.3 to 1.0 and a water content in the range of 0.5 wt% to 9 wt%. The method according to claim 1,
Wherein the size of the edge R of the molded body is 1.0 mm or more. The method according to claim 1,
Wherein the density of the molded body is in the range of 1.5 g / cc to 3.0 g / cc. The method according to claim 1,
Wherein the average diameter of the molded body is in the range of 5 mm to 100 mm. The method according to claim 1,
The shape of the molded body is,
Wherein the cathode active material is at least one selected from the group consisting of spherical, oval, shell, and mixed forms thereof. The method according to claim 1,
The above-
Wherein at least one of the briquetting machine and the granulator is a briquetting machine and a granulator. The method according to claim 1,
Wherein the binder comprises water. 8. The method of claim 7,
Wherein the binder further comprises at least one of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP). 9. The method of claim 8,
Wherein the content of at least one of the polyvinyl alcohol (PVA) and the polyvinyl pyrrolidone (PVP) is in the range of 0 wt% to 1 wt% based on the mixture of the metal hydroxide and the lithium compound A method for producing a cathode active material. The method according to claim 1,
Wherein the metal hydroxide comprises a compound represented by the following general formula (1) or (2).
[Chemical Formula 1]
M 1 _x M 2 _y M 3 _z (OH) _{2 + δ}
Wherein M1, M2, and M3 are selected from the group consisting of Ni, Co, Mn and combinations thereof, 0? X? 1, 0? Y? 1, 0? Z ?? 1, 0.0????? 0.02, 0 <x + y + z?
(2)
M 1 _x M 2 _y M 3 _z (OH) _{2 + δ}
Wherein M1, M2, and M3 are selected from the group consisting of Ni, Co, Al and combinations thereof, 0.8?? X?? 1, 0? Y? 0.2, 0? Z ? 0.2, 0.0????? 0.02, 0 <x + y + z? The method according to claim 1,
The lithium compound,
Lithium carbonate or lithium hydroxide, and a method for producing the cathode active material for a secondary battery. The method according to claim 1,
The mixture may contain,
And at least one additive selected from the group consisting of oxides or hydroxides of at least one of Zr, Ti, W, Al, Mg, V, Co and Ni, nitrates and combinations thereof. The method according to claim 1,
Wherein the firing comprises:
Placing the molded body in a firing vessel, placing the firing vessel in a firing furnace, and
Supplying at least one of an oxygen-containing gas and an inert gas to the firing furnace and firing
Wherein the positive electrode active material is a positive electrode active material. The method according to claim 1,
After the firing step
And cooling and calcining the fired compacted product. The method for producing a cathode active material for a secondary battery according to claim 1, The positive electrode active material for a lithium secondary battery according to any one of claims 1 to 14. anode;
cathode; And
Comprising an electrolyte,
Wherein the positive electrode comprises the positive electrode active material according to claim 15.

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