KR20170080812A - Cathode active material for lithium secondary battery and preparing method of the same - Google Patents

Abstract

And a lithium secondary battery including the cathode active material. The present invention also relates to a lithium secondary battery including the cathode active material, a method of manufacturing the same, and a lithium secondary battery including the cathode active material.

Description

Technical Field [0001] The present invention relates to a cathode active material for a lithium secondary battery, and a cathode active material for a lithium secondary battery,

The present invention relates to a positive electrode active material for a lithium secondary battery including a precursor having an improved tap density, a method for producing the positive electrode active material for the lithium secondary battery, and a lithium secondary battery including the positive electrode active material.

As the electric, electronic, communication and computer industries rapidly develop, the demand for high performance and high stability secondary batteries is gradually increasing. Especially, due to the thin and simple miniaturization and portability of precision electric appliances, The battery is also required to be thinned and miniaturized.

In response to this demand, a lithium secondary battery is one of the batteries that has been most popular in recent years.

The lithium secondary battery generally includes a positive electrode, an organic electrolyte, a separator, and a negative electrode. These materials are selected in consideration of battery life, charge / discharge capacity, temperature characteristics, stability and the like.

Accordingly, the anode uses a lithium metal oxide, and the separation membrane uses a solvent free polymer electrolyte or a plasticized polymer electrolyte.

In recent years, a lithium secondary battery using lithium titanium oxide (LTO), which has a higher Li intercalation desorption potential than a carbonaceous material, as a negative electrode active material has been used as the negative electrode in recent years, such as graphite or cokes. Has been put to practical use.

However, there is a problem in that the lifetime of the lithium secondary battery rapidly decreases as the charge and discharge are repeated. In addition, the problem of high temperature characteristics is also serious. For this reason, the electrolyte is decomposed due to moisture or other influences inside the battery, the active material is deteriorated, and the internal resistance of the battery is increased.

A lot of efforts are being made to solve these problems. Among them, as a cathode active material property modifying method for a cathode, a manufacturing method of adding a transition metal oxide to suppress additional side reaction and improve the performance of a battery is generally accepted.

As a method for improving the characteristics of the conventional cathode active material, the precursor is heat-treated to improve the tap density. However, there is a difficulty in the manufacturing process due to the application of atmospheric gas (nitrogen and oxygen) during the heat treatment process, and the powder subjected to the heat treatment at a high temperature (600 ° C or more) has poor processability. Thus, (Slurrying) is difficult to apply to a uniform current collector. In addition, cracks in the particle size occur in the electrode plate pressing process, or the spherical particles are broken and the cell performance is deteriorated.

Another prior art Korean Patent Publication No. 2011-0109879 discloses a method of increasing the size ratio of large particles and small particles in order to optimize the distribution of different kinds of powders. However, in the above-mentioned prior art, when the particle size is increased, the thermal stability is improved. However, since the capacity and rate characteristics are lowered, the particle size can not be increased indefinitely. On the other hand, There is a problem that the thermal stability due to the increase is deteriorated, so that there may be difficulties in practical application. Also, since the cathode active material includes the first lithium-nickel composite oxide and the second lithium-nickel composite oxide having different volume particle distributions, the technology for improving the filling density compared to the conventional cathode active material has a low rate characteristic , It is difficult to solve the deterioration problem when a lithium-nickel composite oxide is used.

The present invention provides a cathode active material for a lithium secondary battery including a precursor having an improved tap density, a method for producing the cathode active material for the lithium secondary battery, and a lithium secondary battery comprising the cathode active material.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to a first aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: preparing a precursor including Ni and Mn and then subjecting the precursor to heat treatment to form a heat treatment precursor; Mixing the heat treatment precursor and the non-heat treatment precursor to form a precursor mixture; And mixing the precursor mixture with a lithium-containing compound, followed by heat treatment to produce a cathode active material represented by the following formula (1): < EMI ID =

[Chemical Formula 1]

Ni _x Mn _y M _z C _1-a O _{2 + b} ;

Wherein M is a metal selected from the group consisting of Co, Al, Mg, Cr, Fe, Ti, Zr, Mo, and combinations thereof, x is 1-yz, y is 0.9 Z is not more than 0.5, a is not more than 1, and b is not more than 2. [

The second aspect of the present invention provides a cathode active material for a lithium secondary battery, comprising a heat-treated precursor and a non-heat-treated precursor,

[Chemical Formula 1]

Ni _x Mn _y M _z C _1-a O _{2 + b} ;

Wherein M is a metal selected from the group consisting of Co, Al, Mg, Cr, Fe, Ti, Zr, Mo and combinations thereof; x is 1-yz; , Z is not more than 0.5, a is not more than 1, and b is not more than 2.

A third aspect of the present invention provides a lithium secondary battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the positive electrode includes a positive electrode active material for a lithium secondary battery according to the second aspect of the present invention as a positive electrode active material.

The present invention provides a lithium secondary battery improved in the density of a cathode plate of a cathode active material and the rate characteristics of charging or discharging rate of a battery by improving the tap density by mixing a precursor obtained by heat treating the cathode active material precursor and a non-heat treating precursor.

In the prior art, it has been attempted to increase the filling density by controlling the particle diameters of the Ni and Mn cathode active materials, or simply by controlling the particle sizes of the same kind and the different kinds of active materials. However, by adjusting the particle diameters of the Ni and Mn cathode active materials, The active material, the conductive agent, and the binder are suspended in an appropriate solvent to produce a slurry, and there is a high possibility that the active material is separated due to the difference in density of the active material. On the other hand, The lithium secondary battery thus produced has a disadvantage that battery performance deteriorates due to the difference in specific surface area and thermal stability is deteriorated. However, in the lithium secondary battery according to one embodiment of the present invention, the tap density and the electrode plate density of the final active material are improved by mixing the heat treatment precursor and the non-heating precursor to improve the filling density of the lithium secondary battery, And the capacity can be improved.

1 (a) to 1 (c) are electron microscope images of the cathode active material precursor particles according to Comparative Examples and one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

Throughout this specification, when a member is " on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this 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.

The terms " about ", " substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

The word " step (or step) " or " step " used to the extent that it is used throughout the specification does not mean " step for.

Throughout this specification, the term " combination (s) thereof " included in the expression of the machine form means a mixture or combination of one or more elements selected from the group consisting of the constituents described in the expression of the form of a marker, Quot; means at least one selected from the group consisting of the above-mentioned elements.

Throughout this specification, the description of "A and / or B" means "A or B, or A and B".

Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments and examples and drawings.

According to a first aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: preparing a precursor including Ni and Mn and then subjecting the precursor to heat treatment to form a heat treatment precursor; Mixing the heat treatment precursor and the non-heat treatment precursor to form a precursor mixture; And mixing the precursor mixture with a lithium-containing compound, followed by heat treatment to produce a cathode active material represented by the following formula (1): < EMI ID =

[Chemical Formula 1]

Ni _x Mn _y M _z C _1-a O _{2 + b} ;

Wherein M is a metal selected from the group consisting of Co, Al, Mg, Cr, Fe, Ti, Zr, Mo, and combinations thereof, x is 1-yz, y is 0.9 Z is not more than 0.5, a is not more than 1, and b is not more than 2. [

In one embodiment herein, the precursor comprising Ni and Mn may be, but not limited to, performed by co-precipitation.

In one embodiment of the invention, the heat treatment of the precursor may be performed at a temperature of about 200 < 0 > C to about 900 < 0 > C, but is not limited thereto. For example, the heat treatment of the precursor may be performed at a temperature of from about 200 캜 to about 900 캜, from about 200 캜 to about 800 캜, from about 200 캜 to about 600 캜, from about 200 캜 to about 400 캜, But may be, but not limited to, performed at 600 캜 to about 900 캜, or at about 800 캜 to about 900 캜.

In one embodiment of the invention, the heat treatment precursor may comprise about 0.01 to about 50 parts by weight of the heat treatment precursor relative to about 100 parts by weight of the precursor, and about 100 parts by weight of the heat treatment precursor But may be, but not limited to, about 50 parts by weight to about 99.99 parts by weight. For example, for about 100 parts by weight of the precursor, if the heat treatment precursor comprises about 0.01 part by weight, the non-heat treating precursor may comprise about 99.99 parts by weight, and about 100 parts by weight of the precursor , And the heat treatment precursor comprises about 50 parts by weight, the non-heat treating precursor may include about 50 parts by weight, but the present invention is not limited thereto.

In one embodiment of the invention, the heat treatment precursor and the non-heat treatment precursor may be mixed to improve the tap density, but the present invention is not limited thereto. In the production of the heat treatment precursor, the tap density of the heat treatment precursor may be controlled according to the heat treatment temperature, but the present invention is not limited thereto.

In one embodiment of the invention, the tap density may be from about 1.5 g / cc to about 3.0 g / cc, but is not limited thereto. For example, the tap density may be from about 1.5 g / cc to about 3.0 g / cc, from about 1.5 g / cc to about 2.8 g / cc, from about 1.5 g / cc to about 2.6 g / From about 1.5 g / cc to about 2.2 g / cc, from about 1.5 g / cc to about 2.0 g / cc, from about 2.0 g / cc to about 3.0 g / cc, from about 2.2 g / cc to about 3.0 g / cc, from about 2.4 g / cc to about 3.0 g / cc, from about 2.6 g / cc to about 3.0 g / cc, or from about 2.8 g / cc to about 3.0.

In one embodiment of the present invention, the precursor mixture and the lithium-containing compound may be mixed in a molar ratio of 1: 1 to 1.5: 1, but the present invention is not limited thereto.

In one embodiment of the invention, the heat treatment of the precursor mixture and the lithium-containing compound is performed by heating from about 800 ° C. to about 1,000 ° C. at a rate of about 1 ° C./min to about 5 ° C./min However, the present invention is not limited thereto. Further, in one embodiment of the present invention, it may include, but is not limited to, maintaining the heating at the heating temperature for about 4 hours to about 10 hours after the heating.

The second aspect of the present invention provides a cathode active material for a lithium secondary battery, comprising a heat-treated precursor and a non-heat-treated precursor,

[Chemical Formula 1]

Ni _x Mn _y M _z C _{1 - a} O _{2 + b} ;

Wherein M is a metal selected from the group consisting of Co, Al, Mg, Cr, Fe, Ti, Zr, Mo and combinations thereof; x is 1-yz; , Z is not more than 0.5, a is not more than 1, and b is not more than 2.

The second aspect of the present invention relates to a cathode active material for a lithium secondary battery produced in accordance with the first aspect of the present invention, and a detailed description thereof is omitted. However, in the first aspect of the present invention, The contents can be equally applied even if the description is omitted from the second aspect.

In one embodiment of the present invention, the tap density may be improved by mixing the heat-treated precursor and the non-heat-treated precursor, but the present invention is not limited thereto.

In one embodiment of the invention, the tap density may be from about 1.5 g / cc to about 3.0 g / cc, but is not limited thereto. For example, the tap density may be from about 1.5 g / cc to about 3.0 g / cc, from about 1.5 g / cc to about 2.8 g / cc, from about 1.5 g / cc to about 2.6 g / From about 1.5 g / cc to about 2.2 g / cc, from about 1.5 g / cc to about 2.0 g / cc, from about 2.0 g / cc to about 3.0 g / cc, from about 2.2 g / cc to about 3.0 g / cc, from about 2.4 g / cc to about 3.0 g / cc, from about 2.6 g / cc to about 3.0 g / cc, or from about 2.8 g / cc to about 3.0.

A third aspect of the present invention provides a lithium secondary battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the positive electrode includes a positive electrode active material for a lithium secondary battery according to the second aspect of the present invention as a positive electrode active material.

In the third aspect of the present invention, the detailed description of the parts overlapping with the second aspect of the present invention is omitted, but the description of the second aspect of the present invention can be applied equally to the third aspect.

 In one embodiment of the invention, the cathode plate density of the anode may be from about 2.0 g / cc to about 4.0 g / cc, but is not limited thereto.

In one embodiment of the invention, the electrode plate density of the anode may be, but is not limited to, adjustable according to the pressure of the press during manufacture of the anode.

According to one embodiment of the present invention, the positive electrode is obtained by, for example, suspending a positive electrode active material, a positive electrode conductive agent, and a binder in a suitable solvent, applying the slurry prepared by suspending the positive electrode current collector to a positive electrode current collector, Containing layer and then pressing it. As the conductive agent, it is preferable to use carbon black. Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyacrylonitrile, nitrile rubber, polybutadiene, polystyrene, styrene butadiene rubber, Rubber, butyl rubber, hydrogenated styrene-butadiene rubber, nitrocellulose, carboxymethylcellulose or a mixture thereof is preferably used. At this time, the content of the cathode active material, the conductive agent, the binder and the solvent is a level commonly used in a lithium secondary battery.

According to one embodiment of the present invention, the organic electrolyte may include, but is not limited to, an organic solvent and a lithium salt.

The solvent may be a material known in the art and may be one having a high permittivity (polarity) and a low viscosity and a low reactivity with lithium metal in order to increase the degree of dissociation of ions and smooth the conduction of ions And may be, for example, a mixture of chain-like hydrocarbons and cyclic hydrocarbons. The chain hydrocarbon may be, for example, polyethylene carbonate, ethylene carbonate, or propylene carbonate, and the cyclic hydrocarbon may be, for example, dimethyl carbonate or diethyl carbonate, but may not be limited thereto

As the lithium salt, materials known in the art can be used, and it is preferable to use one having good lattice energy and high dissociation degree, excellent ion conductivity, and good thermal safety and oxidation resistance. The lithium salt may be selected from the group consisting of LiPF ₆ , LiBF ₄ , LiClO ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiCF ₃ SO ₃ , LiC (CF ₃ SO ₃ ) ₃ , LiAsF ₆ , But are not limited thereto.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto.

[ Example ]

≪ Preparation of positive electrode active material precursor >

In the present embodiment, NiSO ₄ -xH ₂ O (≥99%) of Norilsk nickel as the Ni-containing compound and MnSO ₄ -H ₂ O (≥ 99%) of Mechema as the Mn-containing compound were used to prepare the cathode active material precursor 98%) were used. First, Ni-containing compounds and Mn-containing compounds were prepared in the form of hydrates using co-precipitation. The Ni-containing compound and the Mn-containing compound were dissolved in distilled water at 0.25 M and 0.75 M, respectively, to prepare a 2.3 M lithium nickel composite oxide precursor solution. A 2.3 M sodium carbonate aqueous solution and ammonia water were mixed in an appropriate amount, At a speed of 700 rpm. During the coprecipitation reaction, the pH was maintained at pH 7.5 and the average residence time of the solution in the reaction tank was 10 hours. The obtained coprecipitate was obtained after washing with water and _{drying, (Ni 0. 25 Mn 0} . 75) CO 3.

≪ cathode active material precursor Tap density  Improvement>

In order to adjust the tap density of the cathode active material precursor in this embodiment, the precursor of the coprecipitate was heat-treated by the co-precipitation method obtained in the above example.

Example  One

The heat treatment of the coprecipitate precursor was carried out at 400 ° C. under an air atmosphere and the heat treatment was performed for 10 hours to prepare a heat treatment precursor. The mixing ratio of the heat treatment precursor and the non-heat treatment precursor was 5: 5 to adjust the tap density of the cathode active material precursor.

For the preparation of the cathode active material, the precursor powder thus obtained and the Li-containing compound Li ₂ CO ₃ (Li ₂ CO ₃ , ≥99% by Junsei) were mixed at a molar ratio of 1: 1, After heating up to 850 캜 at a heating rate, heat treatment was performed at the above temperature for 10 hours to obtain LiNi _{0 . 5} Mn _{1 . 5} O _{4 -x} .

Example  2

The heat treatment of the coprecipitate precursor was conducted at 500 ° C. under an air atmosphere and the heat treatment was performed for 10 hours to prepare a heat treatment precursor. The mixing ratio of the heat treatment precursor and the non-heat treatment precursor was 5: 5 to adjust the tap density of the cathode active material precursor.

For the positive electrode active material, the precursor powder obtained by using the same method as in Example 1 LiNi _{0. 5} Mn _{1 . 5} O _{4 -x} .

Example  3

The heat treatment of the coprecipitate precursor was conducted at 600 DEG C under an air atmosphere and the heat treatment was performed for 10 hours to prepare a heat treatment precursor. The mixing ratio of the heat treatment precursor and the non-heat treatment precursor was 5: 5 to adjust the tap density of the cathode active material precursor.

For the positive electrode active material, the precursor powder obtained by using the same method as in Example 1 LiNi _{0. 5} Mn _{1 . 5} O _{4 -x} .

Comparative Example  One

The coprecipitate precursor and the Li-containing compound Li ₂ CO ₃ (Li ₂ CO ₃ , ≥99% by Junsei) were mixed at a molar ratio of 1: 1 and heated to 850 ° C. at a rate of 5 ° C./min in an air atmosphere one, then, heat-treated at this temperature for 10 hours LiNi _{0. 5} Mn _{1 . 5} O ₄ .

Comparative Example  2

The heat treatment of the coprecipitate precursor was carried out at 400 ° C. under an air atmosphere and the heat treatment was performed for 10 hours to prepare a heat treatment precursor.

For the positive electrode active material, using the heat-treated precursor powder LiNi in the same manner as Example _{10. 5} Mn _{1 . 5} O ₄ ≪ / RTI >

Electron microscopic images of the cathode active material precursor particles obtained in Example 1 and Comparative Examples 1 and 3 are shown in Figs. 1 (a) to 1 (c), respectively.

1 (a) to 1 (c), the non-heated precursor particles having a large particle size and the heat treatment precursor having a small particle size are uniformly mixed in FIG. 1 (a) have. This is because the influence of the mixing of the non-heating precursor and the heat treatment precursor can uniformly receive the influence of the factors attributable to the improvement of the tap density of the heat source and the lithium source in the production of the cathode active material precursor.

In FIG. 1 (b), a large number of non-heat treated precursor particles having a large particle size are relatively influenced by the heat source of the heat treatment and the lithium source during the production of the cathode active material, and the tap density characteristics are decreased. In addition, in the case of FIG. 1 (c), the number of the heat-treated precursor particles having a small particle size causes the precursor particles to be broken due to the influence of the heat source and the lithium source during the production of the cathode active material.

< Lithium secondary battery  Manufacturing>

In order to produce a lithium secondary battery according to one embodiment of the present invention, the positive electrode is prepared by suspending a positive electrode active material, a positive electrode conductive agent, and a binder in a suitable solvent, applying the slurry prepared by suspending the positive electrode current collector, A cathode active material-containing layer was produced, followed by pressing.

As the positive active material LiNi ₀ prepared in the Examples and Comparative _{Examples. 25} Mn _{0 . 75} O _x was used, and Super-p of Timcal was used as a conductive agent. The weight ratio of the cathode active material, the conductive agent, and the binder was 84: 8: 8, and the slurry was prepared and applied to an aluminum foil to prepare a positive electrode.

On the other hand, a separation membrane of Asahi was used as a separation membrane, and the separation membrane was an electrochemically stable insulating film having a porosity of 30% by volume to 60% by volume in a lithium secondary battery.

The above-prepared anode forming composition was coated on an aluminum foil to a thickness of 25 탆 to prepare a thin electrode plate, dried at 135 캜 for 6 hours, and then rolled at a rolling rate of 40% Respectively.

As the organic electrolytic solution, a solution obtained by mixing 1.2 M LiPF ₆ of lithium salt of Panaxitec with an organic solvent (EC: EMC = 1: 1) was used. The lithium salt may be used alone or as an optional mixture, and the ionic conductivity of the lithium salt in the organic electrolytic solution is preferably in the range of , The concentration of the lithium salt is preferably 0.4 M to 1.5 M.

The negative electrode was used as a metal lithium having a thickness of 500 ㎛ punching a 16.5 mmφ, the positive electrode active material is applied to the electrode plate sheet and then punching a 16.5 mmφ, by laminating the above material in CR2032-type coin cell kit compressed into 1.7 t / cm ² Thereby producing a coin cell (lithium secondary battery).

< Tap density  Measurement>

The tap density of the present example and the comparative example was measured using KYT-4000 (Seishin).

The tap density of the cathode active material was measured by weighing the cathode active material in a 100 cc or 200 cc vessel, measuring the height of the vessel after performing the number of times of the tap density measuring apparatus 400 times, and obtaining the tap density value of the cathode active material.

< Density of plate  Measurement>

In order to measure the electrode plate density of the positive electrode of this example and the comparative example, the positive electrode active material plate was pressed by a press. At this time, progress is made so as not to cause a problem of crushing of the positive electrode active material particles. After pressing, the height of the electrode plate was measured to obtain the calculated density value.

The results of the measurements of the properties of the lithium secondary batteries of Examples 1 to 3 and Comparative Examples 1 and 2 thus prepared are shown in Table 1 below.

[Table 1]

As shown in Table 1, Examples 1 to 3 in which the heat treatment precursor and the non-heat treatment precursor were mixed to adjust the tap density were compared with Comparative Example 1 including only the non-heating precursor and Comparative Example 2 including only the heat treatment precursor It was confirmed that the discharge capacity was higher.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (14)

Preparing a precursor including Ni and Mn, and then heat-treating the precursor to form a heat treatment precursor;
Mixing the heat treatment precursor and the non-heat treatment precursor to form a precursor mixture; And
Mixing the precursor mixture with a lithium-containing compound and then heat-treating the mixture to prepare a cathode active material represented by the following Chemical Formula 1:
Method for producing cathode active material for lithium secondary battery:
[Chemical Formula 1]
Ni _x Mn _y M _z C _1-a O _{2 + b} ;
In Formula 1,
M comprises a metal selected from the group consisting of Co, Al, Mg, Cr, Fe, Ti, Zr, Mo,
x is 1-yz, y is not more than 0.9, z is not more than 0.5, a is not more than 1, and b is not more than 2.
The method according to claim 1,
Wherein the precursor containing Ni and Mn is carried out by coprecipitation.
The method according to claim 1,
Wherein the heat treatment of the precursor is performed at 200 ° C to 900 ° C.
The method according to claim 1,
Wherein the heat treatment precursor is contained in an amount of 0.01 to 50 parts by weight per 100 parts by weight of the precursor.
The method according to claim 1,
Wherein the non-heat treatment precursor is contained in an amount of 50 parts by weight to 99.99 parts by weight with respect to 100 parts by weight of the precursor.
The method according to claim 1,
Wherein the heat treatment precursor and the non-heat treatment precursor are mixed to improve a tap density of the positive electrode active material for a lithium secondary battery.
The method according to claim 6,
Wherein the tap density is 1.5 g / cc to 3.0 g / cc.
The method according to claim 1,
Wherein the precursor mixture and the lithium-containing compound are mixed in a molar ratio of 1: 1 to 1.5: 1.
The method according to claim 1,
Wherein the mixture of the precursor mixture and the lithium-containing compound is heat-treated at a temperature raising rate of 1 ° C / min to 5 ° C / min to 800 ° C to 1,000 ° C.
(1), which comprises a heat-treated precursor and a non-heat-treated precursor,
Cathode active material for lithium secondary battery:
[Chemical Formula 1]
Ni _x Mn _y M _z C _{1 - a} O _{2 + b} ;
In Formula 1,
M is a metal selected from the group consisting of Co, Al, Mg, Cr, Fe, Ti, Zr, Mo,
x is 1-yz, y is not more than 0.9, z is not more than 0.5, a is not more than 1, and b is not more than 2.
11. The method of claim 10,
Wherein the tap density is improved by mixing the heat-treated precursor and the non-heat-treated precursor.
12. The method of claim 11,
Wherein the tap density is 1.5 g / cc to 3.0 g / cc.
An anode, a cathode, a separator, and an electrolyte,
Wherein the positive electrode comprises the positive electrode active material for a lithium secondary battery according to any one of claims 10 to 12 as a positive electrode active material.
14. The method of claim 13,
And the cathode plate density of the anode is 2.0 g / cc to 4.0 g / cc.

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