KR100759456B1 - Positive active material for lithium rechargeable battery and method of preparing same - Google Patents

Abstract

The present invention relates to a cathode active material for a lithium secondary battery and a method for manufacturing the same, wherein the cathode active material is selected from the following Chemical Formulas 5 to 8 including an oxide compound selected from Chemical Formulas 1 to 4 including a surface treatment layer and a surface treatment layer Halogen-containing compounds.

[Formula 1]

Li _x M _1-y M ' _y O ₂

[Formula 2]

Li _x Co _1-y Ni _y O ₂

[Formula 3]

Li _x Co _1-y Mn _y O ₂

[Formula 4]

Li _x Co _m Ni _n M ' _y O ₂

[Formula 5]

Li _x M _1-y M ' _y O _2-z A _z

[Formula 6]

Li _x Co _1-y Ni _y O _2-z A _z

[Formula 7]

Li _x Co _1-y Mn _y O _2-z A _z

[Formula 8]

Li _x Co _m Ni _n M ' _y O _2-z A _z

(In the above formula,

M is Ni or Co, M 'is Al, Ni, Co, Cr, Fe, Mg, Sr, V, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, At least one element selected from the group consisting of Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, and Lr ego,

A is a halogen element,

0.95 ≦ x ≦ 1.1, 0 ≦ y ≦ 0.5, 0 ≦ z ≦ 0.5, m + n = 1-y, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 0.5).

The positive electrode active material for a lithium secondary battery of the present invention contains an oxide compound having a surface treatment layer and a halogen compound at an appropriate ratio, and exhibits excellent charge and discharge characteristics and cycle life characteristics under high rate conditions.

Halogen, cathode active material, lithium secondary battery, surface treatment layer

Description

 A positive electrode active material for a lithium secondary battery and a manufacturing method thereof {POSITIVE ACTIVE MATERIAL FOR LITHIUM RECHARGEABLE BATTERY AND METHOD OF PREPARING SAME}

Figure 1a is a SEM (scanning electronic microscope) photograph showing a magnified 5000 times the positive electrode active material (LiCoO ₂ ) for a lithium secondary battery prepared according to the method of Comparative Example 1.

Figure 1b is a SEM photograph showing a 3000 times magnification of a positive electrode active material (LiCoO ₂ ) for a lithium secondary battery prepared according to the method of Comparative Example 1.

Figure 2a is a SEM photograph showing a magnified 5000 times the positive electrode active material (LiCoO _1.95 F _0.05 ) for a lithium secondary battery prepared according to the method of Comparative Example 2.

Figure 2b is a SEM photograph showing a 3000 times magnification of a positive electrode active material (LiCoO _1.95 F _0.05 ) for a lithium secondary battery prepared according to the method of Comparative Example 2.

Figure 3a is a SEM photograph showing a magnified 5000 times the positive electrode active material (LiCoO _1.95 F _0.05 ) for the lithium secondary battery prepared according to the method of Comparative Example 4.

Figure 3b is a SEM photograph showing a magnified 3000 times the positive electrode active material (LiCoO _1.95 F _0.05 ) for a lithium secondary battery prepared according to the method of Comparative Example 1.

Figure 4 is a graph showing the EDX analysis results of the positive electrode active material for lithium secondary batteries prepared according to the method of Comparative Example 1.

Figure 5 is a graph showing the EDX analysis results of the positive electrode active material for lithium secondary batteries prepared according to the method of Comparative Example 2.

Figure 6 is a graph showing the EDX analysis results of the positive electrode active material for lithium secondary batteries prepared according to the method of Comparative Example 4.

7 is a graph showing charge and discharge characteristics of a battery manufactured using the cathode active material for a lithium secondary battery synthesized according to Comparative Examples 1, 3, and 4. FIG.

8 is a graph showing charge and discharge characteristics of a battery manufactured using the cathode active material for lithium secondary batteries for secondary batteries synthesized according to Examples 1, 3, 5 and Comparative Examples 1 to 2 of the present invention.

9 is a graph showing the discharge capacity of a battery prepared using the positive electrode active material for lithium secondary batteries for secondary batteries synthesized according to Examples 1, 3, 5 and Comparative Examples 1 to 4 of the present invention.

[Industrial use]

The present invention relates to a positive electrode active material for a lithium secondary battery and a method of manufacturing the same, and more particularly, to a positive electrode active material for a lithium secondary battery showing excellent charge and discharge characteristics and high rate cycle life characteristics, and a manufacturing method thereof.

[Prior art]

A lithium secondary battery is prepared by using a negative electrode material capable of reversibly inserting and detaching lithium ions as a positive electrode and a negative electrode, and filling an organic electrolyte or a polymer electrolyte between the positive electrode and the negative electrode, and lithium ions are inserted into the positive electrode and the negative electrode. Electrical energy is generated by oxidation and reduction reactions when desorption.

Lithium metal or a carbonaceous material is used as a negative electrode active material of a lithium secondary battery, and when lithium metal is used, there is a risk of explosion due to a short circuit of the battery due to the formation of dendrite. Is being replaced by carbon-based materials.

A chalcogenide compound is used as the cathode active material, and complex metal oxides such as LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiNi _1-x CO _x O ₂ , and LiMnO ₂ have been studied. Among the cathode active materials, LiMn ₂ O _{4, which} is a manganese-based cathode active material, is easy to synthesize, has a low price, and has a low pollution degree to the environment, but has a disadvantage of low electric capacity. In addition, LiNiO ₂ is the cheapest of the positive electrode active material, has the highest discharge capacity, but is difficult to synthesize. Cobalt-based active material, such as LiCoO ₂ has the disadvantage of high price of cobalt, but has the advantage of large electric capacity, excellent thermal stability and charge and discharge characteristics are most widely used. In particular, the cobalt-based active material accounts for more than 95% of the positive electrode active material of the current lithium secondary battery, and it is still a situation that can not find a material to replace the cobalt-based active material.

Recently, studies have been conducted to improve the electric capacity of LiCoO ₂ by doping a LiCoO ₂ active material. For example, Sony has developed LiCo _1-x Al _x O ₂ by doping about 1 to 5% by weight of Al ₂ O ₃ to the LiCoO ₂ positive electrode active material, AT & B Co., Ltd. An active material doped with SnO ₂ was developed. However, there is still a need for research on economical anode slides with improved cycle life characteristics and high electrical properties at high rates.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a cathode active material for a lithium secondary battery excellent in cycle life characteristics and electrical properties at a high rate.

Moreover, an object of this invention is to provide the manufacturing method of the said positive electrode active material for lithium secondary batteries.

In order to achieve the above object, the present invention is an oxide compound selected from Formula 1 to 4 including a surface treatment layer; And it provides a cathode active material for a lithium secondary battery comprising a halogen-based compound selected from the formulas 5 to 8 including a surface treatment layer.

[Formula 1]                     

Li _x M _1-y M ' _y O ₂

[Formula 2]

Li _x Co _1-y Ni _y O ₂

[Formula 3]

Li _x Co _1-y Mn _y O ₂

[Formula 4]

Li _x Co _m Ni _n M ' _y O ₂

[Formula 5]

Li _x M _1-y M ' _y O _2-z A _z

[Formula 6]

Li _x Co _1-y Ni _y O _2-z A _z

[Formula 7]

Li _x Co _1-y Mn _y O _2-z A _z

[Formula 8]

Li _x Co _m Ni _n M ' _y O _2-z A _z

(In the above formula,

M is Ni or Co, M 'is Al, Ni, Co, Cr, Fe, Mg, Sr, V, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, At least one element selected from the group consisting of Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, and Lr ego,

A is a halogen element,

0.95 ≤ x ≤ 1.1, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 0.5, m + n = 1-y, 0 ≤ m ≤ 0.5, 0 ≤ n ≤ 0.5)

The present invention also has a surface treatment layer, having a cobalt-based compound selected from Formulas 1 to 4 and the surface treatment layer, comprising a step of mixing a halogen-based compound selected from Formulas 5 to 8, the positive electrode for a lithium secondary battery It provides a method for producing an active material.

Hereinafter, the present invention will be described in more detail.

The positive electrode active material of the present invention is a mixture of an oxide compound and a halogen compound in which a part of O is substituted with halogen in the oxide compound. The oxide compound used in the present invention is represented by the following Chemical Formulas 1 to 4, the halogen compound is represented by the following Chemical Formulas 5 to 8, and both the oxide compound and the halogen-based compound include a surface treatment layer.

[Formula 1]

Li _x M _1-y M ' _y O ₂

[Formula 2]

Li _x Co _1-y Ni _y O ₂

[Formula 3]

Li _x Co _1-y Mn _y O ₂

[Formula 4]

Li _x Co _m Ni _n M ' _y O ₂

[Formula 5]

Li _x M _1-y M ' _y O _2-z A _z

[Formula 6]

Li _x Co _1-y Ni _y O _2-z A _z

[Formula 7]

Li _x Co _1-y Mn _y O _2-z A _z

[Formula 8]

Li _x Co _m Ni _n M ' _y O _2-z A _z

(In the above formula,

M is Ni or Co, M 'is Al, Ni, Co, Cr, Fe, Mg, Sr, V, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, At least one element selected from the group consisting of Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, and Lr ego,

A is a halogen element, for example F                     

0.95 ≦ x ≦ 1.1, 0 ≦ y ≦ 0.5, 0 ≦ z ≦ 0.5, m + n = 1-y, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 0.5).

The mixing ratio of the oxide compound and the halogen compound is preferably 10 to 90:90 to 10% by weight, more preferably 50 to 90:50 to 10% by weight. If the amount of the oxide-based compound is greater than 90% by weight, the stability is reduced. If the halogen-based compound is used in excess of 90% by weight, the capacity is reduced, which is not preferable.

In the oxide-based compound and the halogen-based compound used in the cathode active material of the present invention, the surface treatment layer may include an oxide or may include one or more hydroxides, oxyhydroxides, oxycarbonates, or hydroxides.

 The surface treatment layer of the present invention may be formed by first encapsulating a compound of Formulas 1 to 4 or a compound of Formulas 5 to 8 as a core compound with a coating solution of an organic solution or an aqueous solution, and drying or heat-treating them. .

The coating element that is a solute in the coating solution is dissolved in an organic solvent or water, and can be used as long as it does not inhibit the insertion of lithium, but as a coating element Mg, Al, Co, K, Na, Ca, Si, Those containing Ti, V, Sn, Ge, Ga, B, As, Zr or mixtures thereof can be preferably used.

The coating organic solution may be prepared by dissolving a coating element, an alkoxide thereof, a salt thereof, an oxide thereof, and the like in an organic solvent, or by refluxing the mixture. The coating aqueous solution may be prepared by dissolving a salt of a coating element or an oxide thereof in water or refluxing the mixture. Suitable solute forms that are soluble in organic solvents or water may be selected by one of ordinary skill in the art. For example, the coating solution containing boron may be prepared by dissolving HB (OH) ₂ , B ₂ O ₃ , H ₃ BO ₃ , and the like in an organic solvent or water.

Organic solvents that can be used when preparing the organic solution in the coating solution include alcohols such as methanol, ethanol or isopropanol, hexane, chloroform, tetrahydrofuran, ether, methylene chloride, acetone and the like.

An alkoxide solution prepared by dissolving an alkoxide such as methoxide, ethoxide or isopropoxide in an alcohol in the organic solution may be preferably used in the present invention. Among such alkoxide solutions, Si alkoxide solutions include tetraethylorthosilicate solutions or tetraethylorthosilicate solutions prepared by dissolving silicates in ethanol.

Representative examples of salts or oxides of coating elements that may be used in preparing the aqueous solution in the coating solution include vanadate such as ammonium vanadate (NH ₄ (VO ₃ )), vanadium oxide (V ₂ O ₅ ), and the like.

The amount of coating element, alkoxide thereof, salt thereof, or oxide thereof thereof added in the preparation of the organic solution or the aqueous solution is preferably 0.1 to 50% by weight, more preferably 5 to 30% by weight relative to the organic solution or the aqueous solution. When the concentration of the coating element, the alkoxide thereof, the salt thereof, or the oxide thereof is lower than 0.1% by weight, there is no effect of coating the oxide compound or the halogen compound with an organic solution or an aqueous solution, and the coating element, the alkoxide thereof, or a salt thereof. If the concentration of the oxide or its oxide exceeds 50% by weight, the thickness of the coating layer is too thick, which is not preferable.

As the coating method, a general coating method such as a sputtering method, a chemical vapor deposition (CVD) method, or a dip coating method may be used. Among these coating methods, the simplest method is a dip coating method, which simply adds a core compound to a coating solution to make a slurry, and then removes the solution.

In addition to the above-described method, the coating method is a mixture of the core compound and the solvent to form a slurry, and then a one-shot process that can simultaneously perform a step of removing the solution and a subsequent drying step. This method is advantageous because it is economical as the process is simple, and the surface treatment layer may be more uniformly formed on the surface.

In more detail about the unification process, the temperature of the mixer is increased while the core compound and the organic solution or aqueous solution are added to the mixer and stirred. At this time, it is preferable to inject a blowing gas to increase the drying speed. As the blowing gas, an inert gas such as nitrogen gas or argon gas may be preferably used as a gas having no CO ₂ or moisture. It is also possible to increase the drying rate by maintaining a vacuum instead of the blowing gas.

The organic solution or aqueous solution is coated on the surface of the core compound, while the excess organic solution or aqueous solution is evaporated off by increasing external temperature and stirring. Therefore, the slurry production process, the solution removal process, and the drying process can be carried out in a unified process in one mixer. For uniform mixing, the core compound and the organic solution or aqueous solution may be added to the mixer, followed by premixing for about 10 to 30 minutes.

The temperature increase of the mixer is carried out by circulating the hot water at which the organic solvent or water, which is a solvent, can be evaporated, preferably 50 to 100 ° C., outside the mixer, and the hot water cooled through the mixer is generally The temperature is circulated through the heat exchanger again.

The mixer is capable of mixing the core compound with the organic solution or the aqueous solution well, increasing the temperature, and there is no particular limitation. In addition, it is preferable that the blowing gas can be injected and the vacuum state can be maintained.

When the general coating process is performed, the powder coated with the organic solution or the aqueous solution is dried at room temperature to 200 ° C. for 1 to 24 hours.

When the unitary coating process is performed, as described above, the drying process is performed simultaneously with the coating, and thus it is not necessary to perform the drying process separately.

According to this drying process, the organic solution or aqueous solution layer formed on the surface reacts with the moisture in the atmosphere to turn into hydroxide. As a result, a surface treatment layer containing hydroxide is formed on the surface of the core compound. At this time, the drying process may be changed so that the surface treatment layer includes oxyhydroxide, oxycarbonate, or hydroxyl carbonate. For example, drying in a carbon dioxide gas atmosphere can form a surface treatment layer containing oxycarbonate or hydroxycarbonate. It may also comprise a mixture of two or more selected from hydroxide, oxyhydroxide, oxycarbonate, and hydroxycarbonate.

The material of which the drying process is completed may be used to prepare a cathode active material for a lithium secondary battery, or a material prepared by heat-treating the material of which the drying process is completed at 600 to 800 ° C. for 1 to 20 hours may be used.

It is preferable that it is 1-300 nm, and, as for the thickness of the surface treatment layer formed by such a process, it is more preferable that it is 1-50 nm. If the thickness of the surface treatment layer formed on the surface is less than 1 nm, the effect of the surface treatment is insignificant. If the thickness exceeds 300 nm, the thickness of the coating layer is too thick, which is not preferable.

The content of the coating element in the surface treatment layer of the core compound of the present invention is preferably 2x10 ^-5 to 2% by weight, more preferably 0.001 to 2% by weight based on the final product.

Oxide compounds and halogen compounds used as cores in the present invention may be commercially available ones or may be those prepared by the following methods.

First, lithium raw material, cobalt raw material, nickel raw material and manganese raw material or mixtures thereof are mixed at a desired equivalent ratio. Lithium nitrate, lithium acetate, lithium hydroxide and the like may be used as the lithium raw material. Cobalt nitrate, cobalt hydroxide, or cobalt carbonate may be used as the cobalt raw material, and manganese dioxide or manganese acetate may be used as the manganese raw material. At this time, in order to promote the reaction of lithium raw material, cobalt raw material, nickel raw material and manganese raw material, an appropriate solvent such as ethanol, water and acetone is added and the mortar grinder is mixed until the solvent is almost gone. (mortar grinder mixing) can also be performed.

 The mixture of lithium raw material, cobalt raw material, nickel raw material and manganese raw material prepared through such a process is subjected to a first heat treatment at a temperature of about 400 to 600 ° C. to prepare a precursor powder in a semi crystalline state. do. When the primary heat treatment temperature is lower than 400 ° C., there is a problem that the reaction between the lithium raw material and the cobalt raw material is not sufficiently performed. In addition, after drying the precursor powder prepared after the first heat treatment, the precursor powder may be remixed at room temperature while blowing in the dry air to uniformly distribute the lithium raw material. Alternatively, the mixture may be remixed with blowing of dry air immediately after the first heat treatment process of the cathode active material.

The precursor powder in a semi-crystalline state obtained through primary heat treatment and remixing is subjected to secondary heat treatment at a temperature of 700 to 900 ° C. for about 10 to 15 hours. If the temperature during the second heat treatment is lower than 700 ° C., there is a problem that a crystalline material is hardly produced. The heat treatment process is carried out by heating at a rate of 1 to 5 ℃ / min while blowing (dry) air or oxygen, and consists of natural cooling after maintaining for a certain time at each heat treatment temperature. In order to distribute the lithium salt more uniformly, it may be remixed at room temperature. The synthesized powder may be classified to have a uniform particle size.

The halogen-based compound is produced by further using a halogen raw material as a starting material, in addition to lithium raw material, nickel raw material, cobalt raw material and manganese raw material. As the halogen raw material, manganese fluoride, lithium fluoride, sodium fluoride (NaF) or calcium fluoride (CaF ₂ ) may be used.

Hereinafter, preferred comparative examples and examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

(Comparative Example 1)

Co ₃ O ₄ and LiOH were measured as starting materials so that the equivalent ratio of Li: Co was 1: 1. These were mixed in an agate mortar bowl using ethanol as the grinding media until all the ethanol solvents had evaporated. The solvent-free mixture was first heat treated under air flow conditions for 10 hours at a temperature of 450 ° C. After the first heat-treated powder was cooled to room temperature, the mixture was once again mixed in an agate mortar, and a mixture of LiOH and Co ₃ O ₄ was uniformed. The homogenized mixture was subjected to a secondary heat treatment at 800 ° C. for 10 hours under air flow conditions to synthesize LiCoO ₂ powder.

The LiCoO ₂ powder, the polyvinylidene fluoride binder and the carbon conductive agent were mixed at a weight ratio of 94: 3: 3, and then, until a uniform paste was added while adding a certain amount of N-methylpyrrolidone. Mixed. The paste was coated with a slurry having a thickness of 100 μm on an Al-foil having a thickness of 25 μm using a doctor blade machine, and then completely removed N-methyl pyrrolidone at 150 ° C., and then compressed under constant compression to have a diameter of 1.6 cm. A circular bipolar plate for an coin cell was prepared. A 2016 coin-type half cell was manufactured using Li-foil as the positive electrode and the counter electrode. At this time, a mixed solution (1: 1 volume L) of ethylene carbonate and dimethyl carbonate in which 1 M of LiPF ₆ was dissolved was used as the electrolyte solution.

(Comparative Example 2)

It was carried out in the same manner as in Comparative Example 1 except that LiCoO _1.95 F _0.05 was prepared using Co ₃ O ₄ , LiOH and LiF as starting materials. At this time, the equivalent ratio of Li: Co was set to be 1: 1.

(Comparative Example 3)

LiCoO ₂ prepared by the method of Comparative Example 1 was added to an Al-isopropoxide solution at a concentration of 0.1% by weight to prepare a slurry. LiCoO ₂ was taken out of the slurry, dried at room temperature for 1 hour, and then at 600 ° C. Heat treatment for 10 hours to synthesize a LiCoO ₂ powder with Al ₂ O ₃ surface treatment layer formed.

(Comparative Example 4)

It was treated in the same way the LiCoO _{1.95 0.05} F prepared by the method of Comparative Example 2 and Comparative Example 3 were prepared LiCoO _1.95 F _0.05 The Al ₂ O ₃ surface-treated layer is formed.

(Example 1)

Comparative Example 3 and formed in the same way a surface-treated Al ₂ O ₃ layer is formed LiCoO ₂ powder as in Comparative Example 4 and the same method the Al ₂ O ₃ surface treatment manufactured with a layer made of LiCoO _1.95 F _0.05 10:90 respectively, the powder A positive electrode active material was prepared by mixing at a weight% ratio.

(Example 2)

And is carried out in the same manner as in Example 1 except for changing the mixing ratio of Al ₂ O _{3 1.95} F _0.05 LiCoO powder surface-treated layer is formed LiCoO ₂ powder and the Al ₂ O ₃ having a surface treatment layer was 30: 70% by weight It was.

(Example 3)

And Al is carried out in the same manner as in Example 1 except that ₂ O ₃ surface-treated layer is formed to change the mixing ratio of LiCoO ₂ powder and _1.95 F _0.05 LiCoO powder is Al ₂ O ₃ surface treated layer formed of a 50: 50 wt% It was.

(Example 4)

And is carried out as Example 1 except for Al ₂ O ₃ ratio of 70:30 for LiCoO _1.95 F _0.05 powders surface-treated layer is formed LiCoO ₂ powder and the Al ₂ O ₃ surface-treated layer is formed to a change in weight percent It was.

(Example 5)

And Al is carried out in the same manner as in Example 1 except that ₂ O ₃ surface-treated layer is formed to change the mixing ratio of LiCoO ₂ powder and _1.95 F _0.05 LiCoO powder is Al ₂ O ₃ surface treated layer formed of a 90: 10 wt% It was.

1A, 2A, and 3A are 5000 times SEM photographs of the positive electrode active material for lithium secondary batteries prepared according to Comparative Examples 1, 2, and 4, respectively. FIGS. 1B, 2B, and 3B are 3000 times SEM photographs. 4 to 6 are EDX analysis results of the positive electrode active materials prepared according to Comparative Examples 1, 2, and 3, respectively. As shown in Figures 1a to 3b, it can be seen that the overall shape is almost similar even if the components constituting the compound is somewhat changed, as shown in Figures 4 to 6, Comparative Example 1 is Co, Comparative Example 2 It can be seen that Co and F, Comparative Example 4 contains Co, F and Al.

In addition, after charging and discharging a coin battery prepared by using the active materials of Comparative Examples 1, 3 and 4 at a charge rate of 0.1C between 4.3 and 2.75V, the charge and discharge characteristics were measured and the results are shown in FIG. 7. . The charge and discharge characteristics can be seen that show the superior to Al ₂ O ₃ positive electrode active material in comparison with the positive electrode active material on the surface of Comparative Example 4 processing layers are formed that does not have the Al ₂ O ₃ surface-treated layer formed in Example 1 and 3 .

In addition, after charging and discharging the coin battery prepared using the positive electrode active materials of Examples 1, 3, 5 and Comparative Examples 1-2 of the present invention at 4.3C 2.75V at a charge and discharge rate of 0.1C, charge and discharge characteristics were The measurement results are shown in FIG. 8.

The potential of the positive electrode active material comprised of the mixture of the positive electrode active material surface-treated with the Al-alkoxide solution is shown. As the ratio of LiCoO ₂ was increased, it showed a potential similar to that of LiCoO ₂ , a conventional cathode active material.

9 is a graph showing the results of measuring a high rate (1C) cycle life of a coin battery manufactured using the positive electrode active materials of Examples 1, 3, 5 and Comparative Examples 1 to 4 of the present invention. It can be seen that the positive electrode active material having the Al2O3 surface treatment layer is superior in cycle life characteristics to the positive electrode active material not having the surface treatment layer, and that the oxide compound and the halogen compound having the Al ₂ O ₃ surface treatment layer are mixed. It can be seen that the cycle life characteristics are better used. In addition, it can be seen that when the amount of the oxide compound increases at the time of mixing, the capacity is higher and the capacity retention rate is excellent.

The positive electrode active material for a lithium secondary battery of the present invention contains an oxide compound having a surface treatment layer and a halogen compound at an appropriate ratio, and exhibits excellent charge and discharge characteristics and cycle life characteristics under high rate conditions.

Claims (10)

An oxide compound selected from Chemical Formulas 1 to 4 including a surface treatment layer; And Halogen-based compound selected from Chemical Formulas 5 to 8 including a surface treatment layer A cathode active material for a lithium secondary battery comprising a. [Formula 1] Li _x M _1-y M ' _y O ₂ [Formula 2] Li _x Co _1-y Ni _y O ₂ [Formula 3] Li _x Co _1-y Mn _y O ₂ [Formula 4] Li _x Co _m Ni _n M ' _y O ₂ [Formula 5] Li _x M _1-y M ' _y O _2-z A _z [Formula 6] Li _x Co _1-y Ni _y O _2-z A _z [Formula 7] Li _x Co _1-y Mn _y O _2-z A _z [Formula 8] Li _x Co _m Ni _n M ' _y O _2-z A _z (In the above formula, M is Ni or Co, M 'is Al, Ni, Co, Cr, Fe, Mg, Sr, V, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, At least one element selected from the group consisting of Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, and Lr ego, A is a halogen element, 0.95 ≦ x ≦ 1.1, 0 ≦ y ≦ 0.5, 0 ≦ z ≦ 0.5, m + n = 1-y, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 0.5. The cathode active material of claim 1, wherein the surface treatment layer comprises an oxide. The cathode active material of claim 1, wherein the surface treatment layer comprises at least one coating compound selected from the group consisting of hydroxide, oxyhydroxide, oxycarbonate, and hydroxycarbonate. The method of claim 1, wherein the surface treatment layer is selected from the group consisting of Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr and mixtures thereof. A cathode active material for a lithium secondary battery comprising at least one coating element. The cathode active material of claim 1, wherein the compound forming the surface treatment layer is amorphous or crystalline. The cathode active material of claim 1, wherein the surface treatment layer has a thickness of 1 to 100 nm. The cathode active material of claim 1, wherein a content of the metal in the surface treatment layer is 2 × 10 ⁻⁵ to 1 wt% based on the cathode active material. Having a surface treatment layer, and having an oxide compound selected from the formulas 1 to 4 and a surface treatment layer, and mixing a halogen-based compound selected from the formulas 4 to 8 The manufacturing method of the positive electrode active material for lithium secondary batteries containing a process. [Formula 1] Li _x M _1-y M ' _y O ₂ [Formula 2] Li _x Co _1-y Ni _y O ₂ [Formula 3] Li _x Co _1-y Mn _y O ₂ [Formula 4] Li _x Co _m Ni _n M ' _y O ₂ [Formula 5] Li _x M _1-y M ' _y O _2-z A _z [Formula 6] Li _x Co _1-y Ni _y O _2-z A _z [Formula 7] Li _x Co _1-y Mn _y O _2-z A _z [Formula 8] Li _x Co _m Ni _n M ' _y O _2-z A _z (In the above formula, M is Ni or Co, M 'is Al, Ni, Co, Cr, Fe, Mg, Sr, V, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, At least one element selected from the group consisting of Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, and Lr ego, A is a halogen element, 0.95 ≦ x ≦ 1.1, 0 ≦ y ≦ 0.5, 0 ≦ z ≦ 0.5, m + n = 1-y, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 0.5). The method of claim 8, wherein the mixing ratio of the oxide compound and the halogen compound is 10 to 90: 90 to 10% by weight. The method of claim 9, wherein the mixing ratio of the oxide compound and the halogen compound is 50 to 90: 50 to 10% by weight.

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