KR100309769B1 - Positive active material for lithium secondary battery and method of preparing the same - Google Patents

Abstract

The present invention relates to a positive electrode active material of a high capacity, long life lithium secondary battery, LiaNi1-x-yCoxMyO2, LiaNi1-x-yCoxMyO2-ZFZ, LiaNi1-x-yCoxMyO2-ZSZ (M is Al, Mg) , Sr, La, Ce, V, Ti is a metal selected from the group consisting of, x is 0 to 1, y is 0.01 to 0.1, z is 0.01 to 0.1, a is 1.00 to 1.1.) Surface treatment using an alkoxide solution provides a cathode active material for lithium secondary batteries, which improves the characteristics of long life, high capacity, and structural stability by modifying the properties of surface structure and surface properties, which are the most important factors affecting the electrochemical reaction. And a method for producing a cathode active material for a lithium secondary battery surface-treated with the metal alkoxide solution.

Description

A cathode active material for a lithium secondary battery and a method of manufacturing the same {POSITIVE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY AND METHOD OF PREPARING THE SAME}

Industrial use field

The present invention relates to a cathode active material for a lithium secondary battery and a method of manufacturing the same, and more particularly, to a cathode active material in which a part of oxygen is replaced with fluorine (F) or sulfur (S) in LiaNi1-x-yCoxMyO2. The present invention relates to providing a positive electrode active material for lithium secondary batteries whose surface properties are modified by surface treatment with a solution.

Conventional technology

As cordless portable devices such as video cameras, cellular phones, personal computers, and the like become smaller, lighter, and higher in functionality, demand for higher energy density is increasing for batteries used as driving power sources. In particular, the rechargeable lithium secondary battery is expected to have a high energy density, and research and development are being actively conducted at home and abroad.

Lithium secondary batteries use a material capable of intercalation and deintercalation of lithium ions as a negative electrode and a positive electrode, and an organic electrolyte or polymer electrolyte capable of moving lithium ions between the positive electrode and the negative electrode. It is prepared by charging, and produces electrical energy by oxidation and reduction reaction when lithium ions are intercalated / deintercalated in the positive electrode and the negative electrode.

Lithium secondary batteries use lithium metal or carbon as an anode material, and a chalcogenide compound of a metal capable of inserting and desorbing lithium ions is used as a cathode material. In the case of using lithium metal as a negative electrode material, there is a risk of explosion due to precipitation of lithium on a dendrite, and the charge and discharge efficiency of the lithium electrode is low, and thus the negative electrode material is being replaced with carbon material instead of lithium metal.

On the other hand, chromium oxide and manganese dioxide (MnO2) were initially used as anode materials. However, due to problems with charging and discharging efficiency and safety, a composite such as LiCoO2, LiMn2O4, LiNi1-xCoxO2 (0 <x <1), LiMnO2, etc. Metal oxides are being studied.

Lithium secondary batteries using Ni-based positive electrode active materials are very likely to form high-capacity batteries due to their large discharge capacity. However, due to the low lifespan characteristics and structural instability of active materials such as LiNi1-xCoxO2 (0 <x <1), Therefore, the development of a nickel-based positive electrode active material to overcome these disadvantages is required.

So far, nickel-based cathode active materials are solid-phase LiNi1-xMxO2 (0 <x <1) powders in which part of Ni is replaced with Co and Mn for the purpose of improving discharge capacity, lifetime characteristics and structural safety based on LiNiO2. Synthesis by solid state pocess, coprecipitation method, poly chelating agent method, etc. has been developed and studied.

Although the charge and discharge capacity of LiNiO2 is more than 200 mAh / g, it has a disadvantage in that it is impossible to use in actual batteries due to poor life characteristics and difficult to synthesize.

In addition, LiCoO2 is widely used because it exhibits electrical conductivity of about 10 ⁻² to 1 S / cm, high battery voltage, and excellent electrode characteristics at room temperature, but has a problem of low stability at high rate charge and discharge.

In order to overcome this drawback, Korean Patent Application No. 97-56444 has developed a powder of LiNi1-xMxO2 in which a part of Ni is substituted with Co or Mn, and recently, LiNi1 which adds a small amount of a third metal other than Co. -x-yCoxMyO2 (M = Al, Mg, Sr, La, Ce et al .: 0 <x <1, 0 <y <1) powders are disclosed, and are also described in US Pat. Appl. No. 5773168 (US Pat. 5773168 discloses a novel invention for a positive electrode active material for a lithium secondary battery in which a part of oxygen in LiNiO2 is replaced with fluorine (F).

However, the existing inventions have solved the problems of the prior art, but still have disadvantages such as low structural stability and life characteristics.

The present invention has been made to solve the problems described above, LiaNi1-x-yCoxMyO2, LiaNi1-x-yCoxMyO2-ZFZ, LiaNi1-x-yCoxMyO2-ZSZ, (M is Al, Mg, Sr, La, Ce, V, Ti is a metal selected from the group consisting of, x is 0 ~ 1, y is 0.01 ~ 0.1, z is 0.01 ~ 0.1, a is 1.00 ~ 1.1. The surface of the powder is treated with a metal alkoxide solution to modify the properties of the surface structure and surface properties, which are the most important factors affecting the electrochemical reaction, thereby improving characteristics of longer life, high capacity, and structural stability. It is to develop and provide an active material.

Another object of the present invention is to provide a method for producing a cathode active material for a lithium secondary battery surface-treated with the metal alkoxide solution.

1 is a cycle of charging and discharging of a coin battery of a) Li1.02Ni0.89Co0.1La0.01O2 and b) Li1.02Ni0.89Co0.1La0.01O1.95F0.05 surface-treated with Al solution (300 ° C). A graph showing the results.

2 is a graph showing the results of one cycle charge / discharge characteristics of a coin cell of Li1.02Ni0.89Co0.1La0.01O1.95F0.05 with or without Al solution (a) without surface treatment b) Al surface process).

FIG. 3 shows charge and discharge during 50 cycles of a coin cell surface treated with Al solution (300 ° C.) a) Li1.02Ni0.89Co0.1La0.01O2 and b) Li1.02Ni0.89Co0.1La0.01O1.95F0.05 A graph showing the characteristic results.

4 is a graph showing the results of charge and discharge characteristics during 50 cycles of a coin cell of Li1.02Ni0.89Co0.1La0.01O1.95F0.05 with or without Al treatment (a) without surface treatment b) Al Surface treatment).

5 is a graph showing evaluation results of charge and discharge characteristics during 50 cycles of a coin battery of Li1.02Ni0.89Co0.1La0.01O2 with or without Al treatment (a) surface treatment with Al solution b) Not surface treated with Al solution).

The present invention is a lithium secondary battery positive electrode active material selected from the group consisting of compounds of the following formulas 1 to 3 in order to achieve the above object, a lithium secondary surface-treated using a metal alkoxide solution to the compound powder of formulas 1 to 3 Provided is a battery positive electrode active material.

[Formula 1]

LiaNi1-x-yCoxMyO2

[Formula 2]

LiaNi1-x-yCoxMyO2-zFz

[Formula 3]

LiaNi1-x-yCoxMyO2-zSz

(In the above Chemical Formulas 1 to 3, M is a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, x is 0 to 1, y is 0.01 to 0.1, z is 0.01 to 0.1 , a is between 1.00 and 1.1.)

In addition, the present invention is a method for producing the positive electrode active material, NiaCoxMy (OH) 2 by synthesizing by coprecipitation method and mixing the powder of LiOH, LiF, NaS and the like to this material and heat-treated the mixture of the formulas 1 to 3 It provides a method for producing a positive electrode active material for lithium secondary batteries of Formulas 1 to 3 including the step of obtaining a positive electrode active material compound and the step of surface treatment of the material using a metal alkoxide solution.

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

As the cathode active material for a secondary battery of the present invention, the compound is selected from the group consisting of the following Chemical Formulas 1 to 3 below.

[Formula 1]

LiaNi1-x-yCoxMyO2

[Formula 2]

LiaNi1-x-yCoxMyO2-zFz

[Formula 3]

LiaNi1-x-yCoxMyO2-zSz

(In the above Chemical Formulas 1 to 3, M is a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, x is 0 to 1, y is 0.01 to 0.1, z is 0.01 to 0.1 , a is between 1.00 and 1.1.)

In order to prepare the compound, it is preferable to use spherical or pseudo-spherical NiaCoxMy (OH) 2 powder co-precipitated with a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti and the like.

NiaCoxMy (OH) 2 is synthesized by coprecipitation. To prepare NiaCoxMy (OH) 2, first, a solution including a nickel salt, a cobalt salt, and a salt of a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, and the like is prepared. At this time, the concentration of the total metal is preferably prepared to be about 2.5 M, water is used as a solvent.

The aqueous metal solution prepared above, NH 4 OH as a complex, and NaOH as a precipitant are continuously supplied to a reactor capable of overflowing.

At this time, the temperature of the reaction vessel is preferably maintained at about 50 ℃, pH in the reaction vessel is preferably maintained at 11-12. In addition, the molar ratio of the supplied metal and NH 4 OH is preferably 1: 0.4-1, and the materials in these reactors are preferably reacted with stirring at a speed of about 900 rpm.

The reacted overflowed reaction precipitate is washed with a solution of water or weak acid until neutral and dried to obtain spherical or pseudo-spherical NiaCoxMy (OH) 2 powder.

The NiaCoxMy (OH) 2 powder prepared above was measured by an equivalent ratio of powders such as LiOH and LiF or NaS, and stirred for about 10 to 30 minutes in a mortar stirrer to prepare a uniform mixture.

The mixed powder is blown at 600 to 800 ° C. while blowing dry air in a furnace controlled by a gas atmosphere. 18 to 22 hours of heat treatment to synthesize the powder of the positive electrode active material of Formula 1 to 4.

At this time, the heat treatment step is carried out by increasing the temperature at a rate of 1 ~ 5 ℃ / min, and after maintaining a constant time at the heat treatment temperature consists of natural cooling. If the heat treatment temperature is 900 ° C or higher, lithium is decomposed, which is not preferable.

The powder thus synthesized is subjected to surface treatment (coating) using a 1 to 30% by weight metal alkoxide solution prepared by dissolving the metal alkoxide powder in alcohol, followed by drying.

The surface treatment method (coating method) performed using a metal alkoxide solution includes general coating methods such as sputtering method, chemical vapor deposition (CVD) method and dip coating method, but are simply coated powder as the simplest coating method. It is preferable to use a dip coating method which is immersed in a solution and then taken out.

The metal alkoxide solution used above is prepared by mixing the alcohol and the metal in an amount corresponding to 1 to 30% by weight based on the alcohol, and then refluxing it. Herein, methanol or ethanol may be used as the alcohol.

In addition, Mg, Al, Co, K, Na, Ca, Si, Ti, and V may be used as the metal, and Mg is preferably used. At this time, when the concentration of the metal is lower than 1% by weight, there is no effect of coating the compound powder selected from the group consisting of the compounds of Formulas 1 to 3 with the metal alkoxide solution, and when the concentration of the metal exceeds 30% by weight of the metal alkoxide The thickness of the coating layer is too thick, which is undesirable.

When the metal alkoxide solution is coated in this way, the thickness of the surface-treated layer is preferably 1 to 10 nm. If the thickness of the surface-treated layer is thick, the electrical properties are degraded, but stability is improved.

In addition, when the surface of the active material is coated with a metal oxide, it is judged to have a life improvement effect because it prevents direct contact between the active material and the electrolyte.

After the powder is surface treated, heat treatment is performed at a temperature of 200 to 1000 ° C. for 2 to 30 hours to prepare a cathode active material for secondary batteries 1 to 3 coated with a new type of metal oxide having a changed surface property. The heat treatment time after the surface treatment is preferably about 10 hours, the heat treatment temperature is preferably about 300 to 500 ℃.

One of the powder particles of the compounds 1 to 3 prepared by surface treatment using a metal alkoxide solution is selected and irradiated with an electron beam to detect secondary ions emitted from the surface. By using SIMS (Secondary Ion Mass Spetroscopy) capable of quantitatively and qualitatively analyzing metals, metals present on the surface of powders were quantitatively and qualitatively analyzed. The experiment result It was found that the metal was present only on the surface of the particles of the compounds of the above 1 to 3 surface treated with the metal alkoxide.

The following presents a preferred embodiment to aid the understanding of the present invention.

However, the following examples are only for the understanding of the present invention and the present invention is not limited to the following examples.

Example 1

LiaNi1-x-yCoxLayO2-zFz (x = 0-1, y = 0.01-0.1, z = 0.01-0.1, a = 1.00-1.1) was prepared, and this material was surface-treated with the metal alkoxide solution.

First, Ni0.89Co0.1La0.01 (OH) 2 was synthesized by coprecipitation to produce Li1.02Ni0.89Co0.1La0.01O1.95F0.05.

To prepare Ni 0.99 Co 0.1 La 0.01 (OH) 2, a solution including a nickel salt, a cobalt salt, and a salt of a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, and the like was prepared. . At this time, the concentration of the total metal was prepared to be about 2.5 M, water was used as a solvent.

The aqueous metal solution prepared above, NH 4 OH as a complex, and NaOH as a precipitant were continuously supplied to a reactor capable of overflowing.

At this time, the temperature of the reactor was maintained at about 50 ℃, pH in the reactor was maintained at 11-12. In addition, the molar ratio of the supplied metal and NH 4 OH was 1: 0.4-1, and the materials in these reactors were reacted with stirring at a speed of about 900 rpm.

The reacted overflowed reaction precipitate was washed with a solution of water or weak acid until neutral and dried to obtain spherical or pseudo-spherical NiaCoxMy (OH) 2 powder.

LiOH and LiF powder was measured in the powder prepared in an equivalent ratio, and stirred for about 10-30 minutes in a mortar stirrer to prepare a uniform mixture.

The mixed powder was blown with dry air in a furnace in which a gas atmosphere was controlled and heat-treated at 700 ° C. for 20 hours to synthesize Li 1.02 Ni 0.98 Co 0.1 La 0.01 O 1.95 F 0.05 active material.

The powder thus synthesized was subjected to surface treatment by a dip coating method using a 5% by weight aluminum isopropoxide solution prepared by dissolving an aluminum isopropoxide powder in alcohol, followed by drying. Heat treatment was performed under dry air blowing conditions at a temperature of about 10 hours to prepare a new type of positive electrode active material coated with aluminum oxide (Al 2 O 3) on a surface of Li 1.02 Ni 0.98 Co 0.1 La 0.01 O 1.95 F 0.05 having changed surface properties.

Example 2

Li1.02Ni0.89Co0.1Mg0.01O1.95F0.05 under the same conditions and methods as in Example 1 except that the positive electrode active material in Example 1 was Li1.02Ni0.89Co0.1Mg0.01O1.95F0.05 A powder coated with aluminum oxide was prepared.

Example 3

15 wt% of aluminum isodium prepared by dissolving Li1.02Ni0.89Co0.1La0.01O1.95F0.05 in the same manner as in Example 1 and then dissolving aluminum isopropoxide powder in alcohol Surface treatment was performed using a propoxide solution, followed by drying. Heat treatment was performed at 900 ° C. for 10 hours at dry air blowing conditions. Li1.02Ni0.89Co0.1La0.01O1.95F0.05 was coated with aluminum oxide. A positive electrode active material was prepared.

Example 4

15% by weight of aluminum isodium prepared by dissolving Li1.02Ni0.89Co0.1Mg0.01O1.95F0.05 in the same manner as in Example 1 and then dissolving aluminum isopropoxide powder in alcohol Surface treatment was performed using propoxide solution, followed by drying. Heat treatment was performed under dry air blowing conditions at a temperature of 900 ° C. for about 10 hours, and aluminum oxide was coated on Li1.02Ni0.89Co0.1Mg0.01O1.95F0.05. A positive electrode active material was prepared.

Comparative Example 1

In order to compare with the results of the Example 1 except that the surface treatment with a metal alkoxide solution in the manufacturing process of Example 1 Li1.02Ni 0.98 Co 0.1 La 0.01O 2 cathode active material was prepared.

First, in order to prepare Li1.02Ni0.89Co0.1La0.01O2, Ni0.89Co0.1La0.01 (OH) 2 was synthesized by coprecipitation method, and then LiOH powder was measured at an equivalence ratio, and the mixture was stirred for about 10-30 minutes in a mortar stirrer. Stirring gave a homogeneous mixture.

The mixed powder was heat-treated at 700 ° C. for 20 hours while blowing dry air in a furnace in which a gas atmosphere was controlled to synthesize a Li 1.02 Ni 0.98 Co 0.1 La 0.01 O 2 cathode active material.

Comparative Example 2

In order to compare with the results of the Example, the composition ratio of La was changed from 0.01 to 0.02 of Comparative Example 1 to prepare a Li 1.02 Ni 0.98 Co 0.1 La 0.02 O 2 cathode active material by the production method of Comparative Example 1.

Comparative Example 3

In order to compare with the results of the Example 2 Li1.02Ni0.89Co0.1Mg0.01O2 cathode active material was prepared except for the surface treatment with a metal alkoxide solution in the manufacturing process of Example 2.

First, Ni0.89Co0.1Mg0.01 (OH) 2 was synthesized by the coprecipitation method of the above embodiment in order to prepare Li1.02Ni0.89Co0.1Mg0.01O2, and then LiOH powder was measured in an equivalence ratio and about 10 in a mortar stirrer. Stir for ˜ 30 minutes to produce a homogeneous mixture.

The mixed powder was heat-treated at 700 ° C. for 20 hours while blowing dry air in a furnace in which a gas atmosphere was controlled to prepare a Li 1.02 Ni 0.98 Co 0.1 Mg 0.01 O 2 cathode active material.

Comparative Example 4

In order to compare with the results of the Example, the composition ratio of Mg was changed from 0.01 to 0.02 of Comparative Example 3 to prepare a Li 1.02 Ni 0.98 Co 0.1 Mg 0.02 O 2 cathode active material in the preparation method of Comparative Example 3.

Comparative Example 5

In order to compare with the results of the Example Li 1.02 Ni 0.98 Co 0.1 La 0.01O 2 was prepared by the following method.

First, Ni0.89Co0.1La0.01 (OH) 2 was synthesized by coprecipitation method, and LiOH powder was measured therein in the equivalence ratio, and stirred for about 10-30 minutes in a mortar stirrer to prepare a uniform mixture.

The mixed powder was heat-treated at 700 ° C. for 20 hours while blowing dry air in a furnace in which a gas atmosphere was controlled to synthesize a Li 1.02 Ni 0.98 Co 0.1 La 0.01 O 2 cathode active material.

The powder thus synthesized was subjected to surface treatment by a dip coating method using a 5% by weight aluminum isopropoxide solution prepared by dissolving an aluminum isopropoxide powder in alcohol, followed by drying. Heat treatment was performed under dry air blowing conditions at a temperature of about 10 hours to prepare a new type of cathode active material coated with aluminum oxide on the Li1.02Ni0.89Co0.1La0.01O2 surface whose surface properties were changed.

The powders synthesized in Examples 1,2,3,4 and Comparative Examples 1,2,3,4,5 were subjected to structural analysis by XRD to confirm their components, and the shape of the particles was observed by SEM. The surface characteristics were confirmed by and TEM.

Charge / discharge characteristic evaluation

In order to evaluate the charge and discharge characteristics of the positive electrode active material powder prepared in Examples 1,2,3,4 and Comparative Examples 1,2,3,4,5, a coin type half cell was prepared. Charge and reversal characteristics were evaluated.

First, in order to manufacture a half-cell, 3 wt% of carbon (trade name: Super P), which is a conductive agent used in manufacturing a positive electrode plate for lithium secondary batteries, and 3 wt% of polyvinylidene fluoride (trade name: KF) -1300).

The positive electrode active material powder, the conductive agent, and the binder were tape cast on an aluminum foil using an NMP solvent to prepare an electrode electrode plate, and then a coin-type half-cell was formed using lithium metal as a counter electrode. After the half-cell was constructed, the capacity and lifespan characteristics of the electrode active material synthesized in the present invention were evaluated.

In order to carry out the charging and discharging evaluation, the evaluation conditions were changed from 2.75 V to 4.3 V under the conditions of 0.1 C ↔ 0.1 C, 0.2 ↔ 0.2 C, 0.5 C ↔ 0.5 C, and 1 C ↔ 1 C. It was.

This charge / discharge characteristic evaluation result is shown to FIGS.

1 is (a) Li1.02Ni0.89Co0.1La0.01O2 of Comparative Example 1 and (b) Li1.02Ni0.89Co0.1La0.01O1 of Comparative Example 1 subjected to surface treatment with an aluminum alkoxide solution and then heat treated at 300 ° C. The initial charge / discharge characteristics of the coin battery of 95F0.05 are shown, and FIG. 3 shows that the powders of (a) and (b) above were characterized by 1 C charge / discharge during 50 cycles. Li1.02Ni0.89Co0.1La0.01O2 is about 3 mAh / g, but when discharged and discharged at 1 C for 50 cycles, Li1.02Ni0.89Co0.1La0.01O1.95F0.05 has about 10% more discharge capacity. It is shown to be excellent.

2 and 4 show initial discharge capacities of (a) and (b) the surface treatment of Li1.02Ni0.89Co0.1La0.01O1.95F0.05 of Example 1 with or without aluminum alkoxide solution. The initial discharge capacity was reduced by about 1% for 50 cycles with and 1C charge / discharge.However, when the characteristics were evaluated during 50 cycles with 1C charge / discharge, it was 74% to 92% for about 20% lifetime. Properties have been improved.

FIG. 5 shows the characteristics of Li1.02Ni0.89Co0.1La0.01O2 surface treated with an aluminum alkoxide solution (a) and without surface treatment (b) with 1 C charge and discharge for 50 cycles. This is an improvement of about 20% from 61% to 82%.

According to the present invention LiaNi1-x-yCoxMyO2 (M is a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, x = 0 ~ 1, y = 0.01 ~ 0.1, a = 1.00 And LiaNi1-x-yCoxMyO2-zFz (M is a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, x = 0 ~ 1, y = 0.01 ~ 0.1 , z = 0.01 ~ 0.1, a = 1.00 ~ 1.1), and the powder heat-treated by the metal alkoxide solution, respectively, has the initial discharge capacity of about 1% in the lithium secondary battery, but the high rate condition such as 1 C In the case of surface treatment, the coating showed that the lifespan characteristics were improved by about 20% during 50 cycles with 1 C charge / discharge. Thus, it was possible to provide a long-life, high-capacity small-size, large-size lithium secondary battery cathode active material.

Claims (8)

A compound selected from the group consisting of Formulas 1 to 3, wherein the compound is a cathode active material for a lithium secondary battery, characterized in that the metal oxide is coated on the surface. [Formula 1] LiaNi1-x-yCoxMyO2 [Formula 2] LiaNi1-x-yCoxMyO2-zFz [Formula 3] LiaNi1-x-yCoxMyO2-zSz (In the above Chemical Formulas 1 to 3, M is a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, x is 0 to 1, y is 0.01 to 0.1, z is 0.01 to 0.1 , a is between 1.00 and 1.1.) The method of claim 1, The metal oxide coated on the surface of the compound is Mg, Si, Ti, Al, V, Co, K, Ca, Na, B A cathode active material for a lithium secondary battery, which is an oxide of a metal selected from the group consisting of: The method of claim 1. The thickness of the layer coated on the surface of the compound is 1 to 100 nm positive electrode active material for a lithium secondary battery. a) LiaCoxMy (OH) 2 (M is a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, x is 0-1, y is 0.01-0.1) step; b) measuring LiOH and LiF, or NaS powder to the compound in an equivalent ratio to prepare a uniform mixture by stirring for 10 to 30 minutes in a mortar stirrer; c) heat-treating the powder of the compound in a furnace in which a gas atmosphere is controlled and performing heat treatment at 700 to 900 ° C. for 15 to 20 hours to prepare a powder of the compound selected from the group consisting of Formulas 1 to 4 below. step; d) performing surface treatment with a metal alkoxide solution (prepared by dissolving metal alkoxide powder in alcohol) prepared in step c) followed by drying; And e) heat-treating the compound of the following Chemical Formulas 1 to 3 subjected to the surface treatment in step d) under a dry air or an oxygen atmosphere blowing condition; Method for producing a positive electrode active material for lithium secondary batteries comprising a. [Formula 1] LiaNi1-x-yCoxMyO2 [Formula 2] LiaNi1-x-yCoxMyO2-zFz [Formula 3] LiaNi1-x-yCoxMyO2-zSz (In the above Chemical Formulas 1 to 3, M is a metal selected from the group consisting of Al, Mg, Sr, La, Ce, V, Ti, x is 0 to 1, y is 0.01 to 0.1, z is 0.01 to 0.1 , a is between 1.00 and 1.1.) The method of claim 4, wherein The metal of the metal alkoxide is Mg, Si, Ti, Al, V, Co, K, Ca, Na, B is a metal selected from the group consisting of a method for producing a positive electrode active material for lithium secondary batteries. The method of claim 4, wherein The concentration of the metal alkoxide solution is 1% to 30% by weight of the method for producing a positive electrode active material for a lithium secondary battery. The method of claim 4, wherein LiaCoxMy (OH) 2 in step (a) (M is Al, Mg, Sr, La, Ce, V, Ti is a metal selected from the group consisting of, x is 0 to 1, y is 0.01 to 0.1. ) Is a method for producing a positive electrode active material for a lithium secondary battery synthesized using a metal aqueous solution containing M or M salt, nickel salt, cobalt salt as a starting material. The method of claim 4, wherein The heat treatment temperature in step e) is 200 to 1000 ℃, the heat treatment time is a method for producing a positive electrode active material for lithium secondary batteries.