KR102043783B1 - 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 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 including the same. According to one or more exemplary embodiments, a method of manufacturing a cathode active material for a secondary battery includes preparing a mixture by mixing a metal hydroxide, a lithium compound, and a binder, preparing a molded body by introducing the mixture into a molded body maker, and then firing the molded body into a plastic container. And a step of firing the same, wherein the molded body may have an aspect ratio (long axis / short axis) of 0.3 to 1.0 and a water content of 0.5% to 9% by weight.

Description

A method of manufacturing a cathode active material for a secondary battery, a cathode active material for a secondary battery manufactured by using the same, and a secondary battery comprising the same. BATTERY INCLUDING THE SAME}

The present invention relates to a method of manufacturing a cathode active material for a secondary battery, a cathode active material for a secondary battery manufactured using the same, and a secondary battery including the same. More specifically, a secondary battery having improved productivity by adjusting the aspect ratio and moisture content of a molded product to an appropriate range. It relates to a method for producing a positive electrode active material for batteries.

Lithium secondary batteries have been widely used as energy storage devices of various devices as their applications are expanded. Accordingly, in recent years, in order to improve the energy density of lithium secondary batteries, development of high capacity electrode active materials has been in progress.

In general, a lithium secondary battery is prepared by using a material capable of reversible intercalation / deintercalation of lithium ions as a positive electrode active material and a negative electrode active material, and filling an electrolyte between a positive electrode and a negative electrode including the same.

A lithium composite metal compound or the like is used as a cathode active material of a lithium secondary battery, and the cathode active material may be manufactured by baking a raw material in powder form at a high temperature.

In the firing process of preparing the positive electrode active material, firing is performed in an atmosphere of air containing oxygen. At this time, the firing atmosphere gas can be easily distributed so that the raw material and oxygen can easily contact each other to improve the firing efficiency. .

Therefore, various attempts have been made to improve the firing efficiency, thereby improving the productivity of the cathode active material manufacturing process.

The embodiments provide a method of manufacturing a cathode active material for a lithium secondary battery with improved productivity while securing excellent life characteristics of a lithium secondary battery, a cathode active material manufactured thereby, and a secondary battery including the same.

Method for producing a positive electrode active material for a lithium secondary battery according to an embodiment of the present invention, preparing a mixture by mixing a metal hydroxide, a lithium compound and a binder, the step of introducing the mixture into a molding machine to produce a molded body, and the Filling the molded body into a firing container and firing, wherein the molded body may have an aspect ratio (long axis / short axis) of 0.3 to 1.0 and a water content of 0.5 to 9 wt%.

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

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

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

In addition, since the produced fired body can easily discharge carbon dioxide generated in the firing process, it is possible to remarkably increase the amount of raw materials that can be loaded into the fired container, thereby ensuring excellent productivity in manufacturing the positive electrode active material. have.

In addition, the lithium secondary battery including the cathode active material manufactured by the above method may ensure excellent life characteristics.

1 exemplarily illustrates an example of a molded product manufactured according to a method of manufacturing a cathode active material for a secondary battery according to one embodiment.
FIG. 2A is a yz plan view of FIG. 1.
FIG. 2B is a xz cross-sectional view of FIG. 1.
3 illustrates another example of a molded article manufactured according to a method of manufacturing a cathode active material for a secondary battery according to one embodiment.
Figure 4 shows a state in which the molded body of Figure 3 is loaded on the saggar.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, the present invention is not necessarily limited to the illustrated.

In addition, throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding the other components unless otherwise stated.

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.

According to one or more exemplary embodiments, a method of manufacturing a cathode active material for a secondary battery may include preparing a mixture by mixing a metal hydroxide, a lithium raw material, and a binder, preparing the molded body by inserting the mixture into a molded body maker, and then firing the molded body into a plastic container. Filling and firing may be included.

At this time, the molded body is characterized in that the aspect ratio (long axis / short axis) is in the range of 0.3 to 1.0, the water content is in the range of 0.5% by weight to 9% by weight.

Specifically, the aspect ratio of the molded body, that is, the long axis / short axis value may be in the range of 0.3 to 1.0, or in the range of 0.5 to 0.8. When the aspect ratio of the molded body satisfies the above range, the strength of the molded body is excellent and the shape of the molded body can be well maintained during the transfer process.

In addition, the water content of the molded body may be, for example, in the range of 0.5% to 9% by weight, more specifically 1% to 8% by weight or 1% to 7% by weight. If the water content of the molded body is less than 0.5% by weight, the mixture is not agglomerated and the production of the molded body is difficult. In addition, when the moisture content exceeds 9% by weight, it is difficult to produce a molded product in a desired shape, and there is a problem that the mixture does not stick to the molded product maker during the molding process.

In the present specification, the moisture content may be measured by comparing the weight before and after evaporating the water into a molded article prepared in the moisture content measuring equipment.

1 illustrates an example of a molded body manufactured according to the method of manufacturing a cathode active material for a secondary battery according to one embodiment, FIG. 2A is a yz 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 process of the present embodiment may have a briquette shape as shown in FIG. 1.

2A and 2B, the edge R may be represented as R1 of FIG. 2A and R2 of FIG. 2B.

The molded bodies represented by R1 and R2 in FIGS. 2A and 2B, respectively, may have an R size of at least 1.0 mm, more specifically, 1.0 mm to 20 mm or 1.0 mm to 8.0 mm. When the R size of the edge of the molded body is less than 1.0 mm, the molded body may be damaged in the process of charging the molded body into the firing container in the firing process described later. Accordingly, there is a problem that the amount of residual lithium increases on the surface of the finally prepared cathode active material due to poor flow of oxygen during firing.

3 illustrates another example of a molded body manufactured according to the method of manufacturing a positive electrode active material according to one embodiment, that is, a spherical shaped body by way of example. Referring to FIG. 3, the manufactured molded body 100 may include a precursor 10 and lithium carbonate 20.

Accordingly, the shape of the molded body may be spherical or elliptical, as shown in FIG.

At this time, the average long diameter of the molded body, that is, the average length of the longest diameter in the molded body may be in the range of 5mm to 100mm or 40 to 60mm. If the average long diameter of the molded body is less than 5mm, the size of the voids formed in the molded body is small, there is a problem that the gas is not smoothly entered. In addition, when the average long diameter of the molded body exceeds 100mm, deformation occurs in the molded body in the firing process, and the contact area between the plastic container and the molded body increases, thereby reducing the life of the plastic container.

That is, the molded article according to the present embodiment is formed to have a size larger than 500 times with respect to the particle size such as metal hydroxide or lithium compound to form voids in the molded article, and then fill it in a baking container to prepare a cathode active material. Can be performed.

Through such pores, oxygen necessary for the reaction in the firing process can be easily introduced to increase the firing efficiency, and the reaction by-products can smoothly discharge water vapor and carbon dioxide from the firing vessel.

Next, the density of the formed body may range from 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 raw material filled per unit firing container is not significantly different from that of the case where the metal hydroxide and the lithium compound powder are loaded and fired without producing the molded body, so that the productivity is not improved. There is a problem. In addition, when the density of the molded body is 3.0g / cc or more, carbon dioxide and water vapor generated in the molded body are not discharged smoothly in the firing process, and as a result, the capacity per unit weight of the positive electrode active material for a lithium secondary battery may be reduced.

In this way, by manufacturing the molded body having a high density, it is possible to significantly increase the amount of powder filled per unit firing container in the firing process, it is possible to significantly improve the productivity.

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

First, a step of preparing a mixture by mixing a metal hydroxide, a lithium raw material and a binder will be described.

The mixture may be prepared by, for example, adding a metal hydroxide, a lithium compound, and a binder to a mixer and mixing the same.

At this time, as a mixer, for example, a granulator or an intensive mixer can 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 μm to 20 μm in the form of aggregated primary particles of 1 μm or less.

In this case, the metal hydroxide may include a compound represented by Formula 1 or Formula 2.

[Formula 1]

M1 _x M2 _y M3 _z (OH) _{2 + δ}

In Formula 1, M1, M2, M3 are each selected from the group consisting of Ni, Co, Mn and combinations thereof, 0 ≤ x ≤ ≤ 1, 0 ≤ y ≤ ≤ 1, 0 ≤ z ≤ ≤ 1, 0.0 ≤ δ ≤ ≤ 0.02, 0 <x + y + z ≤ ≤ 1.

[Formula 2]

M1 _x M2 _y M3 _z (OH) _{2 + δ}

In Formula 1, M1, M2, M3 are each selected from the group consisting of Ni, Co, Al, and combinations thereof, 0.8 ≤ x x ≤ 1, 0 ≤ y ≤ 0.2, 0 ≤ z ≤ ≤ 0.2, 0.0 ≤ δ ≤ ≤ 0.02, 0 <x + y + z ≤ ≤ 1.

Such metal hydroxides may be prepared by conventional methods known in the art, and are not particularly limited, and for example, may be prepared using a solid phase reaction method, a coprecipitation method, a sol-gel method, a hydrothermal synthesis method, or the like.

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

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

The amount of the lithium compound added may range from 28 wt% to 33 wt%, specifically, from 28 wt% to 30 wt%, based on the entire mixture.

Meanwhile, the binder serves to bind the metal hydroxide and the lithium compound, and may include, for example, water. In this case, the amount of the binder may be 0.5% by weight to 9% by weight. When the content of the binder containing water is less than 0.5% by weight, it is difficult to bind the molded body. In addition, when the content of the binder containing water exceeds 9% by weight, the viscosity of the mixture of the metal hydroxide, the lithium compound and the binder is lowered, there is a disadvantage that it is difficult to manufacture the molded body in the desired shape.

In addition, the binder, in addition to water, for example, may further include at least one of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP).

The content of at least one of the polyvinyl alcohol (PVA) and the polyvinyl pyrrolidone (PVP) may range from 0 wt% to 1 wt% based on the mixture of the metal hydroxide and the lithium compound. have. Such a binder is a material that helps to bind in the process of producing a molded body but is burned in the firing process. Therefore, when the binder is added in an excessive amount, a large amount of carbon dioxide may be generated during the firing process, so that the residual lithium carbonate concentration on the surface of the positive electrode active material may increase, so that the content of the binder satisfies the above range.

Meanwhile, the mixture of the metal hydroxide, the lithium compound, and the binder may further include an additive as necessary.

The additive may be, for example, at least one selected from the group consisting of oxides, hydroxides, nitrates, and combinations thereof of at least one of Zr, Ti, W, Al, Mg, V, Co, and Ni, but is not limited thereto. It is not. In the present embodiment, the additive may include Zr (OH) ₄ , which may be included in an amount ranging from 0.01 wt% to 1 wt% based on the entire mixture of the metal hydroxide and the lithium compound. The additive may improve stability by substituting metal ions of the positive electrode active material, and remains in an oxide form on the surface of the positive electrode active material to prevent reaction with the electrolyte.

Next, the mixture is introduced into a molded article manufacturing step to produce a molded article.

In this case, for example, at least one of a briquetting machine and a granulator may be used as the molded product maker. The molding according to the present embodiment is particularly advantageous in that the productivity of the molding can be further improved when molding using a briquetting machine.

The manufacturing process of the molded body may be performed for 0.3 to 2 seconds in the pressure range of 10 to 100 MPa using, for example, a briquetting machine.

Thereafter, the step of firing the molded article prepared as described above is filled in a firing container.

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

That is, the firing may be performed by, for example, 10 hours to 30 hours at a temperature range of 400 to 1100 under an oxygen-containing gas or an inert gas atmosphere, but is not limited thereto. The temperature to time of baking can be suitably changed as needed.

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

In addition, one baking container, for example, a saggar pack, which is arranged in a firing furnace may be one, or two or more may be stacked and two or more layers may be fired.

Subsequently, after the firing step, the fired and pulverized compact is performed.

Cooling and grinding can be carried out by conventional methods known in the art, and are not particularly limited.

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

In the process of manufacturing the positive electrode active material for the secondary battery, the firing process is performed by supplying at least one of an oxygen-containing gas or an inert gas as described above. At this time, the oxygen-containing gas flowing from the outside should be easily distributed in the baking container, for example, the saggar. This is because in this case, the raw material filled in the firing container and oxygen can be contacted to improve the firing efficiency.

In addition, in the firing process, reaction by-products of water vapor and carbon dioxide are generated. Among these by-products, carbon dioxide, in particular, is heavier than the oxygen-containing gas used to control the firing atmosphere and thus remains in the firing vessel and reacts with lithium oxide on the surface of the positive electrode active material to form lithium carbonate during the temperature reduction process.

However, when the concentration of lithium carbonate on the surface of the positive electrode active material is increased, in the case of preparing a slurry using the positive electrode active material, dispersibility may be lowered, resulting in poor processability. In addition, when the positive electrode active material is applied to a lithium secondary battery, there is a problem in that the capacity of the battery is reduced to decrease the life characteristics. Therefore, it is necessary to smoothly discharge carbon dioxide generated during the firing step.

To this end, in the present invention, as described above, after preparing a molded article having an aspect ratio and a water content satisfying a specific range, a mixture thereof was introduced into a firing process, and then a method of manufacturing a cathode active material for a lithium secondary battery was developed. In this case, productivity of the molded product manufacturing process is improved, and the molded product manufactured as described above has voids formed therein. Through such pores, the inflow of oxygen is smooth, thereby increasing the firing efficiency, and the emission of carbon dioxide generated in the firing process is facilitated. Accordingly, the amount of powder that can be filled per unit firing container in the firing process can also be increased, so that the productivity is remarkably improved.

The positive electrode active material prepared according to the embodiment of the present invention may be usefully used for the positive electrode of a lithium secondary battery. The lithium secondary battery includes a cathode and an electrolyte including a cathode active material manufactured 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 positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode.

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

As the negative electrode active material, a material capable of intercalating / deintercalating lithium is used, and for example, lithium metal, lithium alloy, coke, artificial graphite, natural graphite, organic polymer compound combustion body, carbon fiber, or the like. Use

The binder may be polyvinyl alcohol, carboxymethyl cellulose / styrene-butadiene rubber, hydroxypropylene cellulose, diacetylene cellulose, polyvinyl chloride, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene or Polypropylene may be used, but is not limited thereto. The binder may be mixed in an amount of 1 to 30 wt% 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 conductivity without causing chemical changes to the battery. Specifically, graphite such as natural graphite and artificial graphite; Carbon blacks 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 powder, aluminum powder and nickel powder; Conductive whiskeys 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 wt% based on the total amount of the negative electrode active material layer forming composition.

The positive electrode includes a positive electrode active material manufactured by a method of manufacturing a positive electrode active material according to an embodiment. That is, the positive electrode active material, the binder, and optionally a conductive material may be mixed to prepare a composition for forming a positive electrode active material layer, and then the composition may be applied to a positive electrode current collector such as aluminum to produce the composition. In addition, a conductive material, a binder, and a solvent are used similarly to the case of the positive electrode mentioned above.

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

The lithium salt is, 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 _At least one selected from the group consisting of ₄ , LiAlCl ₄ , LiCl, and LiI can be used.

As a solvent of the said non-aqueous electrolyte, For example, Cyclic carbonate, such as ethylene carbonate, propylene carbonate, butylene carbonate, 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 γ-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, etc. can be used, but it is not limited to this. These can be used individually or in combination of multiple pieces. In particular, a mixed solvent of a cyclic carbonate and a linear carbonate can be preferably used.

As the electrolyte, a gel 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 polymer such as polypropylene having chemical resistance and hydrophobicity; Sheets or nonwovens made of glass fibers, polyethylene, and the like can be used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

Hereinafter, the present invention will be described in more detail through 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 Positive Electrode Active Material

Metal hydroxide as Ni _{0 . 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 put into a briquetting machine to prepare a molded 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 mullite saggar, and then fired at 900 ° C. in a sintering furnace in an air atmosphere. The state which the molded object was mounted in the baking container is shown in FIG. At this time, the amount of the molded body filled is 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) Preparation of Secondary Battery

N-methyl-2-pyrroli was 96% by weight of the cathode active material for lithium secondary battery (1), 2% by weight of a conductive material (Denka Black), 2% by weight of a binder (PVDF), and 1% by weight of a thickener (CMC). The slurry was prepared by uniformly mixing in a Don (NMP) solvent.

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

Li-metal (Li-metal) is used as the counter electrode, and 1 mol of LiPF is used in a mixed solvent in which a volume ratio of ethylene carbonate (EC) to dimethyl carbonate (DMC) is 1: 1 as an electrolyte. _{6 A} solution was used.

Using each component described above, a 2032 half coin cell was manufactured according to a conventional manufacturing method.

Comparative example  One

Coprecipitation was used to prepare precursors in the form of metal hydroxides including nickel, cobalt, and manganese.

A half cell was manufactured in the same manner as in Example 1, except that Li ₂ CO ₃ , a lithium raw material, was prepared and uniformly mixed with the precursor to be filled in saggar.

At this time, the filling amount of the mixture filled in the saggar pack is shown in Table 1 below.

Comparative example  2

Metal hydroxide as Ni _{0 . 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 to 15% by weight based on the total weight of the mixture.

The mixture was put into a briquetting machine to prepare a molded body.

However, the molded body did not fall well in the briquetting machine, so it was difficult to measure the aspect ratio, and accordingly, the firing process was difficult to proceed.

Experimental Example  1-residual of positive electrode active material surface Lithium amount  Measure

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

Experimental Example  2-Life Characterization

The life characteristics of the half cells prepared according to Example 1 and Comparative Example 1 were evaluated.

First, using a charger (Maccor) to which a constant current is applied, charge and discharge at 0.1C within a range of 25 ℃, 2.5V to 4.25V, the initial discharge capacity and the initial charge and discharge efficiency are shown in Table 1 below. It was. In addition, charging and discharging were carried out 50 times in the same manner to calculate the capacity retention rate by calculating the ratio of 50 discharge capacity to one discharge capacity, which was defined as the cycle life.

division Example 1 Comparative Example 1 Filling capacity per unit fireproof (kg) 6 3 Residual LiOH (ppm) on the surface of the positive electrode active material 700 1000 Residual Li ₂ CO ₃ (ppm) on the surface of the positive electrode active material 1500 3500 Initial discharge capacity (mA / g, @ 0.1C) 176 173 Initial charge and discharge efficiency (%) 91 88 Capacity Retention Rate (%) (50 ^th / 1 ^st @ 1C) 98 96

Referring to Table 1, in the case of the positive electrode active material prepared according to Example 1, after the molded product having the same characteristics as in the present Example was fired, the surface was compared with Comparative Example 1 in which the powder was fired without producing the molded product. It can be seen that the amount of lithium hydroxide and lithium carbonate remaining in the resin was reduced by 30% or more. Therefore, when manufacturing a cathode active material after manufacturing a fired body having a specific aspect ratio and water content as in the present embodiment, it can be confirmed that the effect of reducing the residual lithium content on the surface of the active material is excellent.

Accordingly, even in the case of the lithium secondary battery including the cathode active material manufactured as in Example 1, the lifespan characteristics were not lowered, and it was confirmed that the battery had excellent life characteristics.

However, even when the molded body was manufactured, it was difficult to properly manufacture the molded body when the water content was high in the mixture of the metal hydroxide and the lithium compound due to the large amount of water input.

In addition, in the case of Example 1, when compared with Comparative Example 1, it can be seen that the load per unit fireproof box also increased by about twice.

Therefore, when manufacturing the cathode active material according to an embodiment of the present invention, it is possible to reduce the residual lithium content of the surface, while increasing the amount of raw material that can be filled per unit firing container while ensuring excellent life characteristics Therefore, productivity can be remarkably improved.

The present invention is not limited to the above embodiments, but may be manufactured in various forms, and a person skilled in the art to which the present invention pertains has another specific form without changing the technical spirit or essential features of the present invention. It will be appreciated that the present invention may be practiced as. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

100: molded body
10: precursor
20: lithium carbonate

Claims (16)

Mixing a metal hydroxide, a lithium compound, and a binder to prepare a mixture;
Injecting the mixture into a molding machine to produce a molding; And
Filling the molded body into a firing container and firing it;
Including,
The molded article has an aspect ratio (long axis / short axis) of 0.3 to 1.0, a water content of 1% to 7% by weight,
The metal hydroxide includes a compound represented by the following formula (1) or formula (2),
The lithium compound is a method for producing a positive electrode active material for secondary batteries which is lithium carbonate or lithium hydroxide.
[Formula 1]
Ni _x Co _y Mn _z (OH) _{2 + δ}
(In Formula 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, 0.0 ≦ δ ≦ 0.02, 0 <x + y + z ≦ 1)
[Formula 2]
Ni _x Co _y Al _z (OH) _{2 + δ}
(In Formula 2, 0.8 ≤ x ≤ 1, 0 ≤ y ≤ 0.2, 0 ≤ z ≤ 0.2, 0.0 ≤ δ ≤ 0.02, 0 <x + y + z ≤ 1) The method of claim 1,
The size of the corner R of the molded body is 1.0mm or more manufacturing method of the positive electrode active material for secondary batteries. The method of claim 1,
Density of the molded body is a method of producing a positive electrode active material for secondary batteries in the range of 1.5g / cc to 3.0g / cc. The method of claim 1,
The average long diameter of the molded body is a method for producing a positive electrode active material for secondary batteries range from 5mm to 100mm. The method of claim 1,
The shape of the molded body,
The manufacturing method of the positive electrode active material for secondary batteries which is at least one of spherical shape, an elliptical shape, a briquette shape, and the shape which mixed these. The method of claim 1,
The molded article manufacturing machine,
A method of manufacturing a cathode active material for a secondary battery, which is at least one of a briquetting machine and a granulator. delete The method of claim 1,
The binder may further include at least one of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP). The method of claim 8,
The content of at least one of the polyvinyl alcohol (PVA) and the polyvinyl pyrrolidone (PVP) is in the range of 0% to 1% by weight based on the mixture of the metal hydroxide and the lithium compound. Method for producing a positive electrode active material. delete delete The method of claim 1,
The mixture is
A method for producing a cathode active material for secondary batteries, further comprising at least one additive selected from the group consisting of oxides, hydroxides, nitrates, and combinations of at least one of Zr, Ti, W, Al, Mg, V, Co, and Ni. The method of claim 1,
The firing step,
Placing the molded body in a firing vessel, and placing the firing vessel in a firing furnace;
Supplying and firing at least one of an oxygen-containing gas and an inert gas to the kiln
Method for producing a cathode active material for a secondary battery comprising a. The method of claim 1,
After the firing step
The method of manufacturing a cathode active material for a secondary battery further comprising the step of cooling and pulverizing the calcined molded body. The cathode active material for a lithium secondary battery prepared by any one of claims 1 to 6, 8, 9, and 12 to 14. anode;
cathode; And
Contains an electrolyte,
The positive electrode is a lithium secondary battery comprising the positive electrode active material of claim 15.

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