WO2018105791A1

WO2018105791A1 - Cathode active material for lithium secondary battery, manufacturing method therefor, and lithium secondary battery comprising same

Info

Publication number: WO2018105791A1
Application number: PCT/KR2016/014474
Authority: WO
Inventors: 권수지; 최수안; 정호준; 신준호; 전상훈; 권성상; 안지선
Original assignee: 주식회사 엘 앤 에프
Priority date: 2016-12-09
Filing date: 2016-12-09
Publication date: 2018-06-14

Abstract

The embodiments of the present invention provide a cathode active material which exhibits an excellent coulombic efficiency and a cycle capacity retention rate of a battery and which can realize a high energy density, a method for manufacturing the same, and a lithium secondary battery comprising the same.

Description

【Specification】

[Name of invention]

Cathode active material for lithium secondary battery, manufacturing method thereof and lithium secondary battery comprising same

Technical Field

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

Background Art

A battery generates electric power by using an electrochemical reaction material for the positive electrode and the negative electrode. A typical example of such a battery is a lithium secondary battery that generates electrical energy by a change in chemical potential (chemi cal potent al) when lithium ions are intercalated / deintercalated at a positive electrode and a negative electrode.

Specifically, in view of the positive electrode of the lithium secondary battery, lithium silver is detached from the positive electrode during layer charging of the battery, and the phenomenon of being inserted from the positive electrode during discharge occurs.

In this regard, the format ion efficiency of the lithium secondary battery is based on a case where 100% of lithium ions inserted at the same amount (at the time of discharge of the battery) are inserted in the same amount (at the time of discharge of the battery).

There are a number of factors influencing such chemical conversion efficiency. Among them, factors such as crystal structure and particle size of a positive electrode active material, which are components of a positive electrode, are known.

In terms of structure, a phase change of the positive electrode active material occurs due to the detachment and insertion of lithium ions, and it is known to use a positive electrode active material containing Co as a method of alleviating such phase shift. In other cases, it has been found that the phase change is less mitigating.

On the other hand, in theory, the more the use of the positive electrode active material having a smaller particle size, the higher the chemical conversion efficiency of the battery. Since the layer discharge of the battery is a redox reaction from a broad viewpoint, the reaction is the higher the reaction area of the positive electrode active material. It is increasing. This phenomenon is called Kinetic ic.

However, the improvement in reaction by this Kinetic i phenomenon is not limited to the removal and insertion of lithium ions, but also applies to reaction with electrolyte. That is, the smaller the size of the positive electrode active material, the more active the formation of a solid electrolyte interphase (SEI) layer that acts as a resistance on the surface, which is deepened as the charge and discharge of the battery is repeated to increase the capacity retention rate. It is a factor to reduce.

[Detailed Description of the Invention]

[Technical problem]

In order to solve the above-mentioned problems, a positive electrode active material, a method for manufacturing the same, and a lithium secondary battery including the same, which exhibit excellent chemical conversion efficiency and capacity retention rate, and which can implement a high energy density. To provide.

Technical Solution

In one embodiment of the present invention, the particle size of the lithium metal oxide particles having a particle size of ¾ or less (excluding 0), the small particles (C); And a lithium metal oxide particle assembly comprising lithium metal oxide particles having a larger particle size than the small particles; and a coating layer disposed on at least a part of the particles forming the lithium metal oxide particle aggregate. Provided is a cathode active material for a lithium secondary battery, in which the small particles occupy a volume of 10 vol% or less (excluding 0 vo l%) of the total volume (100 vol%) of the aggregate of the lithium metal oxide particles. The small particles (C) may include lithium metal oxide particles having a molar ratio of lithium / metal less than 1, lithium metal oxide particles having a molar ratio of lithium / metal of 1 or more, and including Ti as a dopant, or a combination thereof.

The small particles (C) may each include 300 ppm or more of Ti as a dopant.

The small particles (C), respectively, do not contain Mg as a dopant, or may include less than 3000ppm (except 0 ppm).

The small particles (C) may be lithium metal oxide particles each containing 300 ppm or more of Ti and less than 3000 ppm of Mg (excluding 0 ppm) as a dopant. The small particles (C) may be lithium metal oxide particles each containing Co as an essential element.

Specifically, the volume of 10 vol% or less (excluding 0 vol%) of the total volume (100 vol%) of the lithium metal oxide particle set, more specifically, 0.01 vol% or more, 1 vol% or less, 0.5 vol% The small particles (C) may occupy a volume of 1 vol% or more.

The lithium metal oxide particles having a larger particle size than the small particles in the lithium metal oxide particle set include lithium metal oxide particles (A) having a particle size of more than 7 jm; And lithium metal oxide particles (B) having a particle size of more than 2 and 7 urn or less.

At least 10 vol% of the total volume of the lithium metal oxide particle aggregate (100 vol¾) may be occupied by the sum of the volume of the small particles (C) and the particles (B), and the balance may be occupied by the particles (A). .

The coating layer may include phosphate, lithium phosphate, or a combination thereof, and further include an oxide selected from the group consisting of lithium metal phosphate, metal phosphate, lithium metal oxide, metal oxide, and combinations thereof. can do. In another embodiment of the present invention, small particles (C) which are lithium metal oxide particles having a particle size of m or less (excluding 0;); And a lithium metal oxide particle set comprising lithium metal oxide particles having a larger particle size than the small particles; and comprising a coating layer disposed on a surface of at least some of the particles forming the lithium metal oxide particle set. Particles occupy less than 10 vol% (except 0 vol%) of the total volume of the lithium metal oxide particle assembly (100 vol%) and have a density of at least 3.9 g when compressed to 200 MPa at room temperature. / cc or more, discharge capacity after 40 cycles at a room temperature of 0.5C, discharge 1.0C, and 3.0V to 4.5V at room temperature is more than 97% of the discharge capacity after 1 cycle (discharge capacity after 40 cycles / 1 The positive electrode active material for lithium secondary batteries which has a discharge capacity * 100 <after a cycle is provided.

Specifically, the positive electrode active material is 0.2 / 0.2C relative to Li + / Li at room temperature, And when the battery is driven under the conditions of 3.0V to 4.5V, the format ion efficiency may be 97% or more.

More specifically, the positive electrode active material has a density (Pel let Dens i ty) of at least 4.0g / cc or more at 200 MPa in phase silver, 0.2 / 0.2C for Li + / Li, and 3.0V to 4.5 at room temperature When the battery is operated under the condition of V, the format i on efficiency is 98% or more, and the discharge capacity is 1 after 40 cycles when the battery is operated under the conditions of 0.5C, discharge 1.0C, and 3.0V to 4.5V at room temperature. 98 ¾ »or more of the discharge capacity after the cycle (discharge capacity after 40 cycles / discharge capacity after 100 cycles * 100%). In another embodiment of the present invention, by firing a mixture comprising a metal oxide supply material and a lithium supply material having a large particle size, preparing a large particle lithium metal oxide powder; Calcining a mixture comprising a small particle metal oxide material and a lithium feed material to produce a small particle lithium metal oxide powder; Preparing a mixture of the large particle lithium metal oxide powder and the small particle lithium metal oxide powder; Adhering a coating raw material to a surface of a mixture of the large particle lithium metal oxide powder and the small particle lithium metal oxide powder; And calcining the complex to which the coating raw material is attached, wherein the metal oxide feed material having a small particle size is particles having a size of 1.5 or less (excluding 0), and the metal oxide supply material having a large particle size. Provides a method for producing a cathode active material for a lithium secondary battery, which is a particle having a size larger than that of the small particle metal oxide supply material.

The small oxide metal oxide supply material may be particles containing Co as an essential component.

In a mixture including the metal oxide supply material and the lithium supply material having the small particle diameter, the molar ratio of lithium / metal may be 1 or less.

The mixture including the small particle metal oxide feed material and the lithium feed material may further include any one of a Ti feed material _{, a} quality feed _, and an Mg feed material, or may further include both the Ti feed material and the Mg feed material. In the step of preparing the small particle size lithium metal oxide powder, the firing temperature may be 750 to 1,050 ^° C.

In the step of preparing a small particle size lithium metal oxide powder, the minimum particle size is more than 0.1 / / m 0.5 μΐΆ or less, the D50 particle diameter is 0.5 / more than 1 «m or less, and the maximum particle size is more than 4 and 7 izm or less Powders consisting of lithium metal oxide particles can be produced.

The large particle metal oxide feed material may be particles having a size of 3 to 20.

In the preparing of the large particle size lithium metal oxide powder; the firing temperature may be 750 to 1, 050 ^° C.

In the step of preparing a mixture of the large particle size lithium metal oxide powder and the small particle size lithium metal oxide powder; large particle size lithium metal oxide powder: small particle size lithium metal oxide powder = 5: 5 to 9: 1 Can be combined.

In the step of firing the mixture to which the coating raw material is attached; the firing temperature may be 650 to 950 ^° C. In another embodiment of the present invention, a positive electrode comprising a positive electrode active material according to system 1; A negative electrode including a negative electrode active material; And an electrolyte;

【Effects of the Invention】

According to the embodiments of the present invention, the chemical conversion efficiency and cycle capacity retention rate of the battery are excellently expressed, and further, the energy density may be improved. [Brief Description of Drawings]

1 is. The relationship between the particles (A), the particles (B), and the particles (C) included in the positive electrode active material provided in one embodiment of the present invention is shown in a BenBiagram.

2 is a SEM photograph of Preparation Example 1 (scale bar: 10 kPa).

3 is a SEM photograph of Preparation Example 3.3 (scale bar: 10).

4 is a SEM photograph of Preparation Example 4 (scale bar: 10; Mn). 5 is an SEM photograph of one particle of Preparation Example 3 at a high magnification (more than 10,000 magnification) (scale bar: 2 μm).

6 is a SEM photograph of Preparation Example 8 (scale bar: 10 // in).

7 shows PSD analysis results of Preparation Examples 1 and 3. FIG.

8 shows the results of PSD analysis of Preparation Example 10 (denoted as "composite coating powder"), Preparation Example 6 (denoted as "large particle powder") and Preparation Example 3 (denoted as "small particle powder"). .

[The best form for carrying out invention]

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, by which the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

In relation to particle size in this specification, DO.9 particle diameter is 0.1, 0.2, 0.3 .... 3, 5, ， .... 10, 20, 30 ^ The particle size when the particles of the active material are accumulated up to 0.9% by volume, and the particle size of D6 is the particle size when the particles are accumulated up to 6% by volume, and D10 is when the particles are accumulated up to 10% by volume. The particle size, D50 particle size, refers to the particle size when particles are accumulated up to 50% by volume, and the particle size, D95, refers to the particle size when particles are accumulated up to 95% by volume. Bi-modal Cathode Active Material

In one embodiment of the present invention, small particles (C) which are lithium metal oxide particles having a particle size of 2 or less (excluding 0); And a lithium metal oxide particle set comprising lithium metal oxide particles having a larger particle size than the small particles; and a coating layer disposed on a surface of at least some of the particles forming the lithium metal oxide particle set. The small particles occupy a volume of 10 vol% or less (excluding 0 vol%) of the total volume (100 vol%) of the lithium metal oxide particle assembly, and provides a cathode active material for a lithium secondary battery. The "particle size" means the size of particles classified according to PSD (Particle Size Distribution). The cathode active material provided in one embodiment of the present invention is a cathode active material in which two kinds of lithium metal oxide particles having different particle sizes are mixed by a so-called bi-modal technology, and has been compressed to 200 MPa from silver. It is advantageous to realize a compression density of 3.9g / cc or more.

However, when implementing the bimodal cathode active material, it is necessary to properly control the size and blending ratio of the lithium metal oxide particles to be blended, and include a coating layer on at least a part of the surface. i ty) is at least 3.9g / cc and can achieve a format ion efficiency of 97% or more when the battery is operated at a temperature of 0.2 / 0.2C for Li + / Li and 3.0V to 4.5V at room temperature. And discharge capacity after 40 cycles when the battery is driven under conditions of charge 0.5C, discharge 1.0C, and 3.0V to 4.5V at a phase silver of at least 97% of the discharge capacity after 1 cycle ( The cycle retention ratio of the discharge capacity after 40 cycles / discharge capacity * 100% after 1 cycle) can be simultaneously implemented. In this regard, in one embodiment of the present invention, an optimum for excellence of the above three effects can be achieved. article With the present a bimodal cathode active material.

Specifically, the positive electrode active material satisfying the particle size, blending ratio, and coating layer conditions presented in one embodiment of the present invention has an advantage of expressing compression density, chemical conversion efficiency of the battery, and cycle retention excellently. Can be confirmed in the evaluation examples described later.

Hereinafter, a cathode active material provided in an embodiment of the present invention will be described in more detail. Location ^■ Size and proportion

Cathode active material provided in one embodiment of the present invention, the particle size is 2 / less (but, except 0) is a small particle (C) of the lithium metal oxide particles; And lithium metal oxide particles having a particle size larger than those of the small particles; lithium metal oxide particles comprising 10 vol% or less of the total volume (100 vol) of the lithium metal oxide particles (but 0 vol%). The small particles occupy a volume. . When satisfying such particle size and blending ratio, the small particles can fill the voids between the lithium metal oxide particles having a larger particle size than the small particles, so that a large amount of positive electrode active material can be accumulated in a unit volume. In addition, it is advantageous to increase the density during compression and to improve the energy density of the battery. In addition, the chemical conversion efficiency of the battery is improved by the excellent reaction properties of the small particles, while the improvement of the reaction properties with the electrolyte is prevented by the lithium metal oxide particles having a larger particle size than the small particles, thereby preventing a decrease in cycle capacity retention. Can be. Coating layer

On the other hand, the positive electrode active material provided in one embodiment of the present invention, includes a coating layer located on the surface of at least a portion of the particles forming the lithium metal oxide particle set.

That is, the coating layer may be present on some or all of the small particles and on the surface of some or all of the lithium metal oxide particles having a larger particle size than the small particles.

The particles in which the coating layer is present are advantageous in that the phase change caused by the detachment and insertion of lithium aions is suppressed, thereby improving the cycle capacity retention rate of the battery.

Specifically, the coating layer may include phosphate, lithium phosphate, or a combination thereof, and an oxide selected from the group consisting of lithium metal phosphate, metal phosphate, lithium metal oxide, metal oxide, and combinations thereof. It may be a composite coating layer further comprising.

Such a coating layer may contribute to improvement of battery characteristics by suppressing oxidative decomposition of the positive electrode active material by reaction with an electrolyte at high voltage and providing a dr iving force for increasing the degree of diffusion of Li ions into the positive electrode active material. . Small particle composition

The small particles (C), the lithium metal oxide of the molar ratio of lithium / metal less than 1 Particles, lithium / metal molar ratio of one or more, and may include lithium metal oxide particles containing Ti as a dopant, or a combination thereof. Herein, metal means all metals (including dopants) except lithium in the lithium metal oxide particles.

Generally, for the small particle size of the lithium metal oxide particles, D50

Small particle size precursors of 1 or less are used. However, at a normal firing temperature of 750 to 1, 050 ^° C (preferably 800 to 100 C C), the larger the amount of Li, the more the growth of lithium metal oxide particles is promoted by the synthetic promoting action (Fl ux effect). Can be.

Thus, in one embodiment of the present invention, a method of setting the molar ratio of lithium / metal in the small particle precursor to 1 or less was considered. It was confirmed by the evaluation example mentioned later that particle growth was suppressed and the small particle which has a particle size of 2 or less (however, more than 0) is formed also at normal baking temperature.

On the other hand, the lower the molar ratio of lithium / metal, the less the movement of lithium, it may be difficult to smoothly express the basic battery characteristics (for example, capacity characteristics).

Thus, in one embodiment of the present invention, a method of adding an element that suppresses grain growth during firing of the small particle size precursor as a dopant is considered. Specifically, Ti is one of the elements that suppress mipza growth. In this regard, even if the molar ratio of lithium / metal is 1 or more, the addition of Ti in an amount corresponding to the increased content of L i results in a particle having a particle size of 2 β or less (more than 0 m) even at a normal firing temperature. It was confirmed in the evaluation examples to be described later that is formed. Of course, doping of Ti may be applied when the molar ratio of lithium / metal is less than one. 、

However, even with the same molar ratio of lithium / metal to the small-size precursors of the same size, the size of the lithium metal oxide particles formed may vary depending on the amount of Ti added with the dopant. Specifically, when the Ti content is 300ppra or more, small particles having a particle size of 2 μm or less (but greater than 0) are formed, but when the Ti content is less than 300 ppm, particles larger than zm may be formed under the same conditions. have. The reason why the size of the lithium metal oxide particles formed according to the Ti content varies in various ways is related to the extent to which the growth of grain boundaries is suppressed by the precipitates. Specifically, during high temperature firing for crystallization, a phenomenon in which a compound including a dopant is precipitated to the grain boundary of the dopant occurs, because the precipitate precipitates as a kind of covering action to inhibit the growth of the grain boundary, and inhibits the growth of the crystal. This is because the degree of the inhibitory effect varies depending on the type and amount of elements added for the purpose.

Accordingly, the small particles (C) may each contain 300 ppm or more of Ti as a dopant. On the other hand, dopant does not contain Mg or, if included, the content can be controlled to less than 3000ppm (except 0 ppm).

On the other hand, the small particles (C), respectively, may be lithium metal oxide particles containing Co as an essential member element. Co is an element that can alleviate the phase shift caused by the detachment and insertion of lithium ions. Specific particle size and blending ratio

As will be described in more detail below, the positive electrode active material provided in one embodiment of the present invention, after mixing a large particle size lithium metal oxide powder prepared from a large particle precursor and a small particle size lithium metal oxide powder prepared from a small particle precursor, It may be obtained through a surface coating process.

In such a mixed powder, particles having a size smaller than the minimum particle size (Dmin) of the large particle size lithium metal oxide powder (A) before mixing, may have the characteristics of the small particle lithium metal oxide powder before mixing.

Specifically, the particles having the characteristics of the small particle size lithium metal oxide powder before mixing even in the mixed powder, the particle size, that is, the particle size larger than the small particles, but has a size smaller than the Dmin of the large-size lithium metal oxide powder Particles.

More specifically, Dmin of the large-diameter lithium metal oxide powder may be about 7; Based on this, the lithium metal oxide particles having a larger particle size than the small particles in the lithium metal oxide particle set include lithium metal oxide particles (A) having a particle size greater than 7; And particles Lithium metal oxide particles (B) having a size of greater than ¾ 隱 or less than 7 // m.

In this regard, in the total volume (100 vol%) of the aggregate of the lithium metal oxide particles, a volume sum of the particles (C) and the particles (B) occupies a volume of at least 10 vol%, and the balance is the particles ( A) can occupy. Referring to FIG. 1, the relationship between the particles (A), the particles (B), and the particles (C) will be clearly understood.

More specifically, the volume of 10 vol% or less (excluding 0 vol%) of the total volume (100 vol) of the lithium metal oxide particle set, more specifically, the volume of 0.01 vol% or more and 1 vol% or less, 0.5 vol% The small particles (C) may occupy a volume of 1 vol% or more. When satisfying this specific range, the effects described above can be optimized. Concrete composition

Lithium metal oxide particles included in the positive electrode active material provided in one embodiment of the present invention may include a compound represented by the following formula (1), regardless of the particle size.

Lixdi -.- AD Ot Formula (1)

(In Formula (1), 0.8 <x <1.2, 0 <m <0.04, 0 <z <0.04, 1.8 ≦ t ≦ 2.2, M may include Co and optionally include Ni, Mn, and combinations thereof) A may be selected from the group consisting of Mg, Ca, Sr, Ba, and combinations thereof, and D may further include Ti, Zr, Ce, Ge, Sn, Al, Sb, and combinations thereof.)

At this time, 0 <m + z <0.05. Where m + z is the total amount of A and D dopants. That is, other elements other than Ti and Mg described above may be included as dopants, but the above range needs to be satisfied. Bimodal Cathode Active Material for Optimal Battery Performance

In another embodiment of the present invention, small particles (C) which are lithium metal oxide particles having a particle size of / m or less (excluding 0; ΜΠ); And particles than the small particles Lithium metal oxide particles comprising a large size of the lithium metal oxide particles; comprising a coating layer located on the surface of at least some of the particles constituting the lithium metal oxide particles aggregate, wherein the lithium metal oxide particles The small particles occupy a volume of 10 vol% or less (excluding 0 vol¾) of the total volume (100 vol), and the compressive density from the silver to 200 MPa is at least 3.9 g / cc. At room temperature, the discharge capacity after 40 cycles is at least 97% of the discharge capacity after 1 cycle (discharge capacity after 40 cycles / discharge capacity after 1 cycle) when the battery is driven at layer temperature of 0.5C, discharge 1.0C, and 3.0V to 4.5V. 100%), to provide a positive electrode active material for a lithium secondary battery.

This satisfies the particle size, blending ratio, and coating layer conditions of the bi-modal cathode active material described above, and thus is a cathode active material capable of improving the compression density and further optimizing the chemical conversion efficiency and cycle capacity retention of the battery. Specifically, the compressive density of the positive electrode active material may have a particle size similar to that of the positive electrode active material but higher than that of the positive electrode active material which is not a bimodal form. For example, the positive electrode active material may be compressed to 200 MPa at room temperature. Peel et Densi ty has at least 3.9g / cc and can express high energy density.

At the same time, the battery to which the positive electrode active material is applied may exhibit a cycle capacity retention rate of 97% when driven at the above limited conditions at room temperature. Furthermore, the battery to which the positive electrode active material is applied may have a format ion efficiency of 97% or more when driven under conditions of 0.2 / 0.2C, and 3.0V to 4.5V with respect to Li + / Li at room temperature.

More specifically, the positive electrode active material has a density (Pel let Densi ty) of at least 4.0g / cc or more at 200 MPa at room temperature, 0.2 / 0.2C for Li + / Li, and 3.0V to 4.5V at phase silver When the battery is driven under phosphorus conditions, the battery has a format ion efficiency of 98% or more, and the battery is discharged after 1 cycle after 40 cycles when operating the battery at room temperature under 0.5 C, discharge 1.0 C, and 3.0 V to 4.5 V. More than 98% of discharge capacity (after 40 cycles, after discharge cycle / 1 cycle Discharge capacity * ioo%).

Such excellent battery characteristics can be achieved by appropriately controlling the particle size, blending ratio, and coating layer conditions described above. For a detailed description thereof, reference may be made to the above description and an evaluation example described later. Method for preparing bi ᅳ modal cathode active material

In another embodiment of the present invention, by firing a mixture comprising a metal oxide feed material and a lithium feed material having a large particle size, preparing a large particle lithium metal oxide powder; Calcining a mixture comprising a small particle metal oxide material and a lithium feed material to produce a small particle lithium metal oxide powder; Preparing a mixture of the large particle lithium metal oxide powder and the small particle lithium metal oxide powder; Adhering a coating raw material to a surface of a mixture of the large particle lithium metal oxide powder and the lithium metal oxide small particle powder; And calcining the mixture to which the coating raw material is attached, wherein the metal oxide feed material having a small particle size is a particle having a size of 1.5 // m or less (excluding 0) and the metal oxide supply having the large particle size. The material provides a method for producing a cathode active material for a lithium secondary battery, which is a particle having a size larger than that of the small particle metal oxide feed material.

This is achieved by mixing the large-size lithium metal oxide powder prepared from the large particle precursor and the small-size lithium metal oxide powder prepared from the small particle precursor, and then subjecting the bi-modal cathode active material described above to a surface coating process. It is a method that can be obtained.

Here, the small particle size precursor means a metal oxide supply material having the small particle size, and is a particle having a size of 1.5 or less (excluding 0). In addition, the large particle size precursor means a metal oxide supply material having the large particle size, and means a particle having a larger size than the small particle metal oxide supply material.

Hereinafter, the manufacturing method will be described in detail, and descriptions overlapping with those described above will be omitted. Small particle precursor mixture manufacturing process

In a mixture including the small particle metal oxide supply material and the lithium supply material, the molar ratio of lithium / metal may be 1 or less. As a result, the growth of particles is suppressed, and small particles having a particle size of 2 m or less (but greater than 0 // m) are formed even at a normal firing temperature, as described above.

The mixture including the small particle metal oxide feed material and the lithium feed material may further include any one of a Ti feed material and an Mg feed material, or may further include both the Ti feed material and the Mg feed material. In this regard, even if the molar ratio of lithium / metal is 1 or more, when Ti in an amount corresponding to the increased Li content is added, the particle size of 2 {M or less (but more than 0 // m) is achieved even at a normal firing temperature. The branched particles are formed as described above. Of course, doping of Ti may be applied when the molar ratio of lithium / metal is less than one.

The small oxide metal oxide supply material may be particles containing Co as an essential component. Co has been described above as an element capable of alleviating the phase shift caused by the detachment and insertion of lithium ions. Small particle precursor firing process (small particle powder manufacturing process)

In the step of preparing the small-size lithium metal oxide powder; the firing temperature may be 750 to 1, 050 ^° C. This is a conventional calcined silver for crystallization, and detailed description thereof is omitted as it is generally known. In the step of preparing a small particle size lithium metal oxide powder, the minimum particle size is greater than 0.5 / 1 / m or less 0.5, the D50 particle diameter is greater than 0.5 μΐα 1 / an or less, and the maximum particle size is greater than 4 7 ΜΠ Powders consisting of lithium metal oxide particles below can be prepared. Large Particle Precursor Mixture Manufacturing Process

The large particle diameter metal oxide feed material may be particles having a size of 3 to 15. Large particle precursor firing process (large particle powder manufacturing process) In the step of preparing the large particle size lithium metal oxide powder, the firing temperature may be 750 to 1,050 ^° C. This is the usual firing temperature for crystallization, the details of which are omitted as they are generally known. Large particle powder and small particle powder mixing process

When satisfying such a mixing ratio, a cathode active material meeting the conditions described above can be obtained. However, when the small particle size lithium metal oxide powder is included less than the above range, there is a problem that the gap between the large particle size lithium metal oxide powder is not properly filled, the integration efficiency is lowered. On the other hand, when the small particle size lithium metal oxide powder is contained in excess of the said range, there exists a problem that the powder which fills the space | gap between the said large particle size lithium metal oxide powder remains.

For example, in the Example mentioned later, large-size lithium metal oxide powder: small particle size lithium metal oxide powder was set to 8: 2. Coating process

The coating process is performed on the small particle powder, the large particle powder, the black silver, the large particle powder and the small particle powder mixed powder.

Accordingly, the coating layer may be formed on the surface of some or all of the particles included in the powder to be coated.

The coating raw material may be a phosphate coating raw material. For example, it may be phosphoric acid (H ₃ P0 ₄ ), ammonium dihydrogen phosphate (NH ₄ H ₂ P0 ₄ ), diammonium hydrogen phosphate ((NH ₄ ) ₂ HP0 ₄ ), or a combination thereof.

In the step of firing the mixture to which the coating raw material is attached; firing silver may be 650 to 95CTC. At this firing temperature, a coating layer containing phosphate, lithium phosphate, or a combination thereof may be formed. Furthermore, a composite coating layer further comprising an oxide selected from the group consisting of lithium metal phosphate, metal phosphate, lithium metal oxide, metal oxide and combinations thereof may be formed.

BEST MODE FOR CARRYING OUT THE INVENTION Production Example Manufacture of Lithium Metal Oxide Powder Production Example 1 (Small Size Powder)

Dry mixing of Li ₂ C0 ₃ , C03O4 (D50 1ra), 300 ppm of Ti0 ₂ , and 300 ppm of MgC0 ₃ was made such that the molar ratio of Li / Me in the mixture was 0.98. Me is based on all cationic metals except Li, ie Co, Ti, and Mg.

Lithium metal oxide powder obtained by heat-treating the mixture at 900 to 1000 ^° C. for 10 hours was prepared as Preparation Example 1. Manufacture example 2 (small particle size powder)

Except for changing 300 ppm of Ti0 ₂ to 100 ppm, the rest of the lithium metal oxide powder obtained in the same manner as in Preparation Example 1 was used as Preparation Example 2. Preparation Example 3 (Small Size Powder)

Except for changing Ti0 ₂ 300ρριτι to 2000 ppm, the rest of the lithium metal oxide powder obtained in the same manner as Preparation Example 1 was used as Preparation Example 3. Preparation Example 4 (Small Size Powder)

Except for changing 300 ppm Ti0 ₂ to 2000 ppm and changing 300 ppm MgC0 ₃ to 4000 ppm, the rest of the lithium metal oxide powders obtained in the same manner as Preparation Example 1 were used as Preparation Example 4. Preparation Example 5 (Small Size Powder)

Dry mix Li ₂ C0 ₃ , Co ₃ 0 ₄ (D50 Ιμ), 300 ppm Ti0 ₂ , but in the mixture The molar ratio of Li / Me was set to 1.015.

The lithium metal oxide powder obtained by heat-treating the mixture at 900 to iooo ^° C for 10 hours was made as Preparation Example 5. Preparation Example 6 (large particle size powder)

Li ₂ C0 ₃ , C03O4 (D50 14 // m), Ti0 ₂ 500 ppm, and MgC0 ₃ 100 ppm were dry mixed but the Li / Me ratio in the mixture was 1.024.

The mixture was heat-treated with 900 to KXXrC for 10 hours to obtain a lithium metal oxide powder of Preparation Example 6. Production Example 7 (large particle size combined powder)

The total amount of the powder of Preparation Example 6 and the powder of Preparation Example 1 was set to 100 g, but the mixing ratio was mixed into a dry mixer using Preparation Example 6: Preparation Example 1 = 8: 2 (based on the weight ratio). As a result, a lithium metal oxide powder obtained in a state in which a large Ga particle size was common was used as Preparation Example 7. Production Example 8 (large particle size ton sum powder)

Except for changing the powder of Preparation Example 1 to the powder of Preparation Example 3, the rest was the same as in Preparation Example 7 to prepare a lithium metal oxide powder obtained in a large particle size o common state as Preparation Example 8. Production Example 9 (large particle size combined powder)

Except for changing the powder of Preparation Example 1 to the powder of Preparation Example 4, the remainder was the same as in Preparation Example 7 to replace the lithium metal oxide powder obtained in a state where the large particle size is common, It was set to three. Production Example 10 (coated powder after mixing large particle size)

With respect to the powder of Preparation Example 8, MgC0 ₃ powder lOOOOppm, Ti (0H) ₄ powder lOOOOppra, (NH ₄ ) ₂ HP0 powder 2000ppm was dry mixed, MgC0 ₃ powder, Ti (0H) ₄ on the powder surface of Preparation Example 8 Powder, and a mixture with (NH ₄ ) ₂ HP0 ₄ powder attached Prepared.

The mixture was heat-treated at 800 ^° C. for 6 hours in a kiln to form a bi-modal coated with part or all of the surface of each large particle size particle _. Lithium metal oxide powder in the form was obtained. ^'' Experimental Example 1 SEM image

The small particle size powder (C) of manufacture example 1 (FIG. 2), manufacture example 3 (FIG. 3), and manufacture example 4 (FIG. 4) using the Normal-SEM made from JE0L, and manufacture example 8 (FIG. 6) SEM images of large and small particle size powders were taken.

Production Example 1 (Fig. 2) and when compared to the SEM images of the Preparation Example 3 (FIG. 3), it is possible to make sure that eu ^1, the particle size distribution of even as the amount of Ti increases in the small particle size powder.

In addition, in contrast to the SEM photographs of Preparation Example 3 (FIG. 3) and Preparation Example 4 (FIG. 4), as the Mg content is increased in the small particle size, a phenomenon in which small particles and large particles are clearly distinguished, that is, particle uniformity You can see the fall.

Specifically, FIG. 5 is a SEM photograph of one particle of Preparation Example 3 at a high magnification (more than 10,000 magnification), and from this, it can be seen that the particle size is smaller than 2 and the particle shape is equilateral.

On the other hand, when observing manufacture example 8 (FIG. 6), it can confirm that each particle of manufacture examples 3 and 6 was mixed evenly. Experimental Example 2: PSDCParticle Size Distribution

With a PSD meter of S3500. Model manufactured by Mi crotrac, particle size distribution for each powder of Preparation Examples 1 to 10 was measured, and the results are recorded in the tables and FIGS. 7 and 8.

TABLE 1

Manufacturing example 2 0. 13 1.43 4.62 入 «

Preparation Example 3 0.33 0.78 4.44

Preparation Example 4 0.78 2.85 13.66 Human Bran

Manufacturing example 5 0. 13 1.70 5.98 人 Win «

Preparation Example 6 7.13 19.07 62.23 Large particle size powder

Preparation Example 7 0.13 17.55 62.23 Preparation Example 1 and Preparation Example 6 Mixed Powder Preparation Example 8 0. 13 17.43 62.23 Preparation Example 3 and Preparation Example 6 Mixed Powder Preparation Example 9 0.78 18.26 62.23 Preparation Example 4 and Preparation Example 6 Preparation of Mixed Powder Example 10 1.50 17.76 62.23 Preparation Example 3 and Preparation Example 6 Mixed Powder Coating For reference, in each Preparation Example of Table 1, the minimum particle size was recorded in Dmin and the maximum particle size in Dmax, and the D50 particle size according to the general definition. Recorded.

1) Evaluation of Small Particle Powder

In Table 1 and FIG. 7, the measurement results of Preparation Examples 1 to 3, in which the Li / Me molar ratio is less than 1 and the Mg doping amount is the same, are found. As the doping amount of Ti increases, Dmax and D50 decrease. .

In addition, in the measurement result of the small particle powder manufacture example 5 whose Li / Me molar ratio is more than 1,

Even if the Li / Me molar ratio is greater than 1, it can be seen that if the Mg content is minimized and Ti doping amount is properly controlled as necessary for particle size control, Dmax and D50 are controlled to a level similar to Preparation Example 1.

Based on these results, it can be seen that Ti is more than 500ppm and can be doped with 300ppm or more, for example, to form a particle size ^"as appropriate. In addition, it can be seen that it is necessary to control the Mg so as not to be doped or less than 2000ppm when doping.

2) Evaluation of Large Particle Powder

In addition, it can be confirmed that Dmin of the large particle size powder of Preparation Example 6 is larger than each Dmax of Preparation Examples 1 to 3 and Preparation Example 5, which are small particle powders. 3) Evaluation of Mixed Powder

For this reason, Preparation Examples 7 and 8 have large particle size powders, but particles having a size smaller than Dmin of Preparation Example 6 at least in the PSD of Preparation Example 8 exhibit the characteristics of the particles of Preparation Examples 1 and 3. It can be seen from having.

4) Evaluation of Coating Powder

On the other hand, in Table 1, in the case of Preparation Example 10 surface-coated after large particle size powder mixing, it is confirmed that Dmi n is increased than Preparation Example 8.

This is because, in the firing process for coating, the particles having a very small particle size of 1 among the small particle powders become slightly larger as they are combined with adjacent particles (large particle size or small particle size).

More specifically, the PSD results of Preparation Example 10 (coated powder after mixing), Preparation Example 6 (large particle powder), and Preparation Example 3 (small particle powder) are shown in a graph as shown in FIG. 8.

Referring to FIG. 8, in the total volume (100 vol%) of the powder coated in Preparation Example 10 after mixing the large particle size powder, the volume occupied by particles having a size smaller than that of Dmin of Preparation Example 6, which is the particle size before mixing, was 10 17% (see Table 2). This, it can be seen that at least 10. 17 vo l% of the powder of Preparation Example 10 has similar characteristics to Preparation Example 3, which is a small particle size before mixing. In particular, small particles having a particle size of 2 or less (but 1.5 or more) in the powder of Preparation Example 10 can be confirmed that the total 78 vol ¾>.

TABLE 2

Particle Size Volume Fraction (vol%) Remarks

(卿)

Preparation Example 6 Preparation Example 10

7. 13 0. 12 0.91 Particles (Β)

6.54 Ν / Α 0.86

6.00 Ν / Α 0.84

5.50 Ν / Α 0.83 5.04 N / A 0.82

4.62 N / A 0.81

4.24 N / A 0.76

3.89 N / A 0.74

3.57 N / A 0.70

3.27 N / A 0.70

3.00 N / A 0.65

2.75 N / A 0.56

2.52 N / A 0.45

2.31 N / A 0.34

2.12 N / A 0.33

1.95 N / A 0.26 Particles IS ^''

1.78 N / A 0.23

1.64 N / A 0.17

1.50 N / A 0.12

Note: In Table 2, the percentage of the volume occupied by particles having a specific size classified according to PSD (Particle Size Distribution) among the total volume of each preparation powder. On the other hand, in the case of the surface coating after the mixing of the large particle size powder, the particles occupied by the particles smaller than the Dmin of the large particle size powder before mixing are at least 10.17 vol%, and the volume of the small particles having the particle size of 2 or less (but 1.5 or more) When 0.78 vol%, in Experimental Example 3 to be described later, it was confirmed that the compressive density (Pellet Density) when pressed to 200 MPa at room temperature is at least 3.9g / cc or more. Experimental Example 3 For Production Examples 7 to 9 in which PD measurement large-sized particle powders were mixed and Production Example 10 surface-coated after large-sized particle powder mixing were respectively pressed at 200 MPa at room temperature Pel let Dens i ty was measured and the results are reported in Table 3. TABLE 3

In Table 2, it can be seen that the small particle size powder of Preparation Example 3 having the smallest D50 particle diameter was used for the preparation of Preparation Example 8, and the small particle size powder of Preparation Example 4 having the largest D50 particle diameter was used for the preparation of Preparation Example 9. have.

Looking at this together with Table 3, it can be seen that the smaller the D50 of the small particle powder mixed for the same large particle powder, the larger the P.D of the mixed powder. On the other hand, the mixing ratio of the large particle size powder is the same, but different only in the surface coating or not P of Preparation Example 10. It can be seen that D is relatively low. This is due to the change in particle size in the firing process for coating, as described above. Experimental Example 4 ： Electrochemical Characteristic Evaluation

(1) Production of coin cell

A battery was fabricated by using Preparation Example 8 in which large and small particle powders were mixed and Preparation Example 10 in which surface coating after large and small particle powders were mixed as positive electrode active materials, respectively. Specifically, 95% by weight of the positive electrode active material, 2.5% by weight of carbon black as a conductive agent, and 2.5% by weight of PVDF as a binder were added to 5.0% by weight of N-methyl-2 pyridone (NMP) as a solvent (solvent). The positive electrode slurry was prepared by the addition.

The positive electrode slurry was applied to a thin film of aluminum (A1), which is a positive electrode current collector having a thickness of 20 to 40, and vacuum dried, followed by roll press to prepare a positive electrode.

Li-metal was used as the negative electrode. A coin cell type half cell was manufactured using 1.15M LiPF6EC: DMC (l: lvol%) as an electrolyte and a cathode prepared as described above.

(2) Evaluation of format ion efficiency

Format ion efficiency was evaluated for batteries fabricated using Preparation Example 8 in which large and small particle powders were mixed and Preparation Example 10 in which surface coating after large and small particle powders were mixed as positive electrode active materials, respectively.

Specifically, the results of measuring the formation efficiency (formation) between 3.0V to 4.5V at 0.2 / 0.2C conditions for Li + / Li at 25 ^° C. are reported in Table 4.

TABLE 4

According to Table 4, compared to Preparation Example 8 in which the large-sized particle powder was mixed, when the Preparation Example 10 coated with the large-size particle powder after mixing was used as the positive electrode active material, the chemical conversion efficiency was better than 97%.

(3) Cycle capacity retention rate evaluation

The cycle capacity retention rate was evaluated for the battery produced using Preparation Example 8 in which large and small particle powders were mixed, and Preparation Example 10 in which surface coating after large and small particle powder mixing were used as the positive electrode active material, respectively.

Specifically, 40/1 retention (the 40th cycle capacity compared to the first cycle capacity) was recorded in Table 5 when the layer discharge was repeated under the layer discharge 0.5C 0.5 discharge 1.0C condition at 3.0V to 4.5V room temperature. TABLE 5

According to Table 5, compared to Preparation Example 8 in which the large-sized particle powder was mixed, when the Preparation Example 10 surface-coated after the large-sized particle powder was mixed as the cathode active material, the chemical conversion efficiency was excellent as 97% or more. Evaluation for Experimental Examples 1 to 4

(1) particle size and uniformity

In the small particle size, it was found that the distribution of the particle size was uniform as the content of Ti was increased (Production Examples 1 to 3), and the particle uniformity was decreased as the content of Mg was increased (Production Examples 3 and 4).

(2) particle size distribution

When the large particle size mixed powder (preparations 7 to 9) and the surface coating after the large particle size mixed (preparation example 10), particles smaller than the Dmin of the large particle size before mixing, may have similar characteristics to the small particle size before mixing have.

Particularly, in the case of the surface coating after mixing the large particle size powder, the particles occupied at least 10.17 vol% of the particles smaller than the Dmin of the large particle size powder before mixing, and among them, those particles having a particle size of 2 im or less (but 1.5; mi or more) When the volume occupied was 0.78 vol%, it was confirmed that the pellet density when pressed at 200 MPa at room temperature is at least 3.9 g / cc or more.

(2) P.D (Pellet Density)

When large and small particle powders are mixed (production examples 7 to 9), the same large particle size It can be seen that the smaller the D50 of the small particle size powder to be mixed with the powder, the larger the P.D of the mixed powder is.

On the other hand, when the mixing ratio of the large-sized particle powder is the same but only the surface coating is different (Manufacturing Examples 8 and 10), P. D is relatively reduced when the surface is coated, but D50 of the small particle powder used is appropriately In consideration of P. It can be seen that D reduction can be minimized.

(3) Format i on efficiency of battery

When the large-size particle powder is mixed (preparation example 8), when the positive electrode active material in the case of the surface coating after mixing the large-size particle (mixing example 10) to the battery, the chemical conversion efficiency may be more than 97%.

(4) cycle capacity retention rate of the battery

When the large-size particle powder is mixed (preparation example 8), when the positive electrode active material of the case (coating example 10) is surface-coated after mixing the large-size particle powder, the capacity retention rate may be more than 97%.

(4) synthesis

The surface-coated positive electrode active material after mixing the large particle size powder has a volume occupied by particles smaller than Dmin of the large particle size powder before mixing, at least 10.17 vol%, and in particular, has a particle size of 2 M or less (but 1.5 or more). The eggplants have a volume of 0.78 vol% and have a Pel let Dens i ty of at least 3.9 g / cc when pressed to 200 MPa at room temperature. Dose retention may be expressed at greater than 97%.

However, in order to suppress the grain growth in the firing process, the small particle powder used for the preparation can be used by reducing the Li / Me ratio in the small particle powder to less than 1 or by appropriately doping Ti expressing the grain growth inhibiting function. have. Specifically, when the Li / Me molar ratio is less than 1 and the Ti content is 300ppm, small particles having a particle size of D50 of 2 _m or less (but 0.5 or more) may be formed. On the other hand, even if the Li / Me molar ratio is 1 or more, in accordance with the increased content of Li If the content of Ti is also increased, small particles having a particle size of 2 or less (but 0.5 or more) may be formed.

Furthermore, as the Ti content is increased in the range of 300 ppm or more, the distribution of the particle size may appear evenly. However, when the Mg content is more than 3000 ppra, particle uniformity may decrease. Therefore, when the Li / Me ratio is less than 1, or the Li / Me ratio is 1 or more, the Ti content is 300ppm or more, and the Mg content is controlled to be less than 4000ppm, it is necessary to use the small particle size powder prepared as a raw material. The present invention is not limited to the above embodiments, but may be manufactured in various forms, and a person of ordinary skill in the art to which the present invention pertains does not change 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.

Claims

[Claim]

[Claim 1]

Small particles (C) which are lithium metal oxide particles having a particle size of 2 / m or less (excluding 0); And lithium metal oxide particles having a larger particle size than the small particles;

It includes a coating layer located on the surface of at least some of the particles constituting the lithium metal oxide particles aggregate,

The small particles occupy a volume of 10 vo l% or less (excluding ^ 0 vo l%) of the total volume of the lithium metal oxide particle aggregate (100 vo l%),

Cathode active material for lithium secondary battery.

[Claim 2]

The method of claim 1,

The small particles (C),

Lithium metal oxide particles having a molar ratio of lithium / metal of less than 1, lithium metal oxide particles having a molar ratio of lithium / metal of 1 or more and including Ti as a dopant, or a combination thereof,

Cathode active material for lithium secondary battery.

[Claim 3]

The method according to claim 2,

The small particles (C) are each,

Lithium metal oxide particles containing Co as an essential element,

Cathode active material for a lithium secondary battery.

[Claim 4]

The method of claim 3,

The small particles (C) are each,

The positive electrode active material for lithium secondary batteries which is lithium metal oxide particle containing 300 ppm or more of Ti as a dopant.

[Claim 5]

In that paragraph

The small particles (C) are each, Lithium metal oxide particles containing less than 3000 ppm Mg (except 0 ppm) as a dopant

Cathode active material for a lithium secondary battery.

[Claim 6]

The method of claim 3,

The small particles (C) are each,

Lithium metal oxide particles containing 300 ppm or more of Ti and less than 3000 ppm of Mg (excluding 0 ppm) as a dopant,

Cathode active material for a lithium secondary battery.

[Claim 7]

The method according to any one of claims 1 to 6,

0 in the total volume (100 vo l%) of the lithium metal oxide particle set. The small particles (C) occupy a volume of not less than 5 vo l% and not more than 1 vo l%.

Cathode active material for lithium secondary battery.

[Claim 8]

The method according to any one of claims 1 to 6,

Lithium metal oxide particles having a larger particle size than the small particles in the lithium metal oxide particle set,

Lithium metal oxide particles (A) having a particle size of greater than 7 βm; And

Lithium metal oxide particles (B) having a particle size greater than 2 / m or less than 7 / ra;

Cathode active material for lithium secondary battery.

[Claim 9]

According to claim 18,

In the total volume (100 vo l%) of the aggregate of the lithium metal oxide particles, a volume sum of the small particles (C) and the particles (B) occupies a volume of at least 10 vo l%, the balance being the particles (A) They occupy,

Positive electrode active material for lithium secondary batteries.

[Claim 10]

The method according to any one of claims 1 to 6, The coating layer is,

A positive electrode active material for a lithium secondary battery, comprising a combination of phosphate, lithium phosphate, or idol.

[Claim claim Π]

The method of claim 10,

The phosphate coating layer is,

Lithium metal phosphate, metal phosphate, lithium metal oxide, a metal oxide, and the oxide further selected from the group consisting of a combination thereof, the cathode active material for a lithium secondary battery.

[Claim 12]

Small particles (C) which are lithium metal oxide particles having a particle size of 2 or less (excluding 0); And lithium metal oxide particles composed of lithium metal oxide particles having a larger particle size than the small particles;

It includes a coating layer located on the surface of at least a portion of the particles constituting the lithium metal oxide particle aggregate,

The small particles occupy a volume of 10 vol% or less (except 0 vol%) of the total volume (100 vol%) of the lithium metal oxide particle assembly,

When compressed to 200 MPa at room temperature, the density (Pe l et Dens i ty) is at least 3.9 g / cc,

When the battery is driven under conditions of 0.5C, 1.0C, and 3.0V to 4.5V charged at phase silver, the discharge capacity after 40 cycles is at least 97% of the discharge capacity after 1 cycle (discharge capacity after 40 cycles / discharge capacity after 1 cycle) 100%)

Cathode active material for lithium secondary battery.

[Claim 13]

The method of claim 12,

When the battery is operated under the conditions of 0.2 / 0.2C, and 3.0V to 4.5V with respect to Li + / Li at room temperature, the format i on efficiency is 97% or more,

Cathode Active Material for Lithium Secondary Battery.

[Claim 14]

The method of claim 13, Pel let Dens i ty when compressed to 200 MPa at room temperature is at least 4.0g / cc,

When the battery is operated under the conditions of 0.2 / 0.2C and 3.0V to 4.5V for Li + / Li at room temperature, the format ion efficiency is 98% or more,

When the battery is operated under the conditions of charging 0.5C, discharge 1.0C, and 3.0V to 4.5V at room temperature, the discharge capacity after 40 cycles is 98% or more of the discharge capacity after 1 cycle (discharge capacity after 40 cycles / discharge capacity after 1 cycle) * 100%)

Cathode active material for lithium secondary battery.

[Claim 15]

Calcining a mixture comprising a large particle diameter metal oxide supply material and a lithium supply material to prepare a large particle diameter lithium metal oxide powder;

Calcining a mixture comprising a metal oxide material having a small particle size and a lithium supply material to prepare a small particle lithium metal oxide powder;

Preparing a mixture of the large particle lithium metal oxide powder and the small particle lithium metal oxide powder;

The large particle size lithium metal oxide powder and the small particle size lithium. Adhering a coating raw material to the surface of the mixture of metal oxide powders; And

Calcining the mixture to which the coating raw material is attached; wherein the metal oxide feed material having a small particle size is particles having a size of 1.5 / or less (excluding 0),

The large particle diameter metal oxide supply material is a particle having a larger size than the small particle metal oxide supply material,

The manufacturing method of the positive electrode active material for lithium secondary batteries.

[Claim 16]

The method of claim 15,

The small oxide metal oxide supply material,

It is a particle containing Co as an essential element,

[Claim 17]

The method of claim 16, In the mixture comprising the metal oxide supply material and the lithium supply material having the small particle,

The molar ratio of lithium / metal is 1 or less ，

[Claim 18]

The method of claim 17,

The mixture comprising the small particle metal oxide feed material and the lithium feed material,

Further comprising a Ti feed material

Method for producing positive electrode active material for lithium secondary battery.

[Claim 19]

The method of claim 18,

The composite including the metal oxide supply material and the lithium supply material having the small particle size,

Further comprising Mg feed material,

[Claim 20]

The method of claim 19,

The composite including the metal oxide supply material and the lithium supply material, which are the small particle,

Further comprising a Ti feed material and Mg feed material,

[Claim 21]

The method according to any one of claims 15 to 20,

In the step of preparing a small particle size lithium metal oxide powder, the firing temperature is 750 to 1, 050 ^° C,

[Claim 22]

The method according to any one of claims 15 to 20,

In the step of preparing the small particle size lithium metal oxide powder, Wherein a powder is made of lithium metal oxide particles having a minimum particle size greater than 0.1 and up to 0.5 iM, a D50 particle diameter greater than 0.5 and up to 1 rn, and a maximum particle size greater than 4 and up to 7 urn,

[Claim 23]

The method according to any one of claims 15 to 20,

The large oxide metal oxide supply material is,

Which is a particle having a size of 3 to 15,

[Claim 24]

The method according to any one of claims 15 to 20,

Preparing the large particle lithium metal oxide powder;

The firing temperature is 750 to 1, 050 ^° C,

[Claim 25]

21. The method according to any one of claims 15 to 20

In the step of preparing a mixture of the large particle lithium metal oxide powder and the small particle lithium metal oxide powder;

Large particle size lithium metal oxide powder: Small particle size lithium metal. Oxide powder = 5: 5 to 9: 1 in a weight ratio of mixing,

[Claim 26]

The method according to any one of claims 15 to 20,

Calcining the complex to which the phosphate feed material is attached; wherein the calcined silver is 650 to 950 ^° C.

[Claim 27]

A positive electrode comprising the positive electrode active material according to claim 1;

A negative electrode including a negative electrode active material; And

Electrolyte; Lithium Secondary Electrode Containing