KR20060128814A - Method of preparing layered cathode active materials with high capacity and high safety for lithium secondary batteries and the product thereby - Google Patents

Abstract

Provided are layered positive electrode active materials for lithium secondary batteries, which have high tap density, high capacity, and improved high-rate characteristics and are superior in thermal safety when lithium is deintercalated, and a preparation thereof. The method for preparing layered positive electrode active materials with high capacity and high safety for lithium secondary batteries comprises the steps of: obtaining precipitate of a metal composite carbonate or metal composite hydroxide mixture by putting an ammonia solution, any one solution selected from aqueous solutions of ammonium carbonate, ammonium hydrogen carbonate, sodium carbonate, and sodium hydroxide, a metal aqueous solution, and carbon dioxide or nitrogen gas into a reactor to react the mixed solution; heating the precipitate to obtain metal composite oxide; and subjecting the heat-treated metal composite hydroxide or metal composite oxide to a mixture reaction with lithium hydroxide and lithium fluoride to obtain lithium metal composite oxide represented by the following formula 1.

Description

Method of preparing Layered cathode active materials with high capacity and high safety for lithium secondary batteries and the product hence}

1 is a perspective view of a reactor used in the production method of the present invention,

SEM photograph of Fig. 2 is an embodiment of a heat treatment at 500 ℃ precursor of 1 [Ni Mn _{0 .43 0 .35 0 .22} Co] O _2,

3 is a SEM photograph (x30000) of the lithium metal oxide Li [Ni _0.43 Mn _0.35 Co _0.22 ] O _1.92 F _{0.08 prepared} in Example 1 and Li [Ni _0.43 Mn _0.35 Co _0.22 ] O ₂ of Comparative Example 1;

4 is an X-ray diffraction pattern of lithium metal oxide Li [Ni _0.43 Mn _0.35 Co _0.22 ] O _1.92 F _{0.08 prepared} in Example 1 and Li [Ni _0.43 Mn _0.35 Co _0.22 ] O ₂ of Comparative Example 1;

* Figure 5 is a lithium metal oxide Li [Ni _0.43 Mn _0.35 Co _0.22 ] O _1.92 F _{0.08 prepared} in Example 1 and Li [Ni _0.43 Mn _0.35 Co _0.22 ] O ₂ 2.8-4.6V charge and discharge experiments of Comparative Example 1 Discharge capacity according to the cycle,

6 is a comparative curve of the lithium metal oxide Li [Ni _0.43 Mn _0.35 Co _0.22 ] O _1.92 F _{0.08 prepared} in Example 1 and Li [Ni _0.43 Mn _0.35 Co _0.22 ] O ₂ 2.8-4.6V rate characteristics of Comparative Example 1,

7 is a differential thermal gravimetric method after charging the lithium metal oxide Li [Ni _0.43 Mn _0.35 Co _0.22 ] O _1.92 F _{0.08 prepared} in Example 1 and Li [Ni _0.43 Mn _0.35 Co _0.22 ] O ₂ 4.6V DSC),

8 is a SEM photograph of the precursor [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O ₂ heat-treated at 500 ° C. formed in Example 2;

9 is a lithium metal oxide prepared in Example 2 SEM photo of Li [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O _1.92 F _0.08 and Li [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O ₂ of Comparative Example 2 (x3000),

10 is a lithium metal oxide prepared in Example 2 Li [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O _1.92 F _0.08 and Li [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O ₂ X-ray diffraction pattern of Comparative Example 2,

11 is a lithium metal oxide prepared in Example 2 Li [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O _1.92 F _0.08 and Li [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O ₂ 2.8-4.6V Discharge capacity according to the cycle of charging and discharging experiment,

12 is a lithium metal oxide prepared in Example 2 After charging Li [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O _1.92 F _0.08 and Li [Ni _0.4 Mn _0.36 Co _0.2 Mg _0.04 ] O ₂ 4.6V Differential thermal gravimetric analysis (DSC) results,

Figure 13 is a SEM photograph of a lithium metal oxide Li _{[Ni 0.4 Mn 0.35 Co 0. Mg} 0.05] O 1.9 F _0.1 of the Comparative Example _{3 Li [Ni 0.4 Mn 0.4 Co} 0.2] O 2 produced in Example 3 (x5000) ,

14 is a lithium metal oxide Li [Ni _0.4 Mn _0.35 Co _0.08 Mg _0.05 ] O _1.9 F _{0.1 prepared} in Example 3 and Li [Ni _0.4 Mn _0.4 Co _0.2 ] O ₂ X-ray diffraction pattern of Comparative Example 3,

15 is a lithium metal oxide Li [Ni _0.4 Mn _0.35 Co _0.1 Mg _0.05 ] O _1.9 F _{0.1 prepared} in Example 3 and Li [Ni _0.4 Mn _0.4 Co _0.2 ] O ₂ 2.8-4.6V charge and discharge of Comparative Example 3 Discharge capacity according to the tested cycle,

16 is a third embodiment prepared in the lithium metal oxide Li _{[Ni 0.4 Mn 0.35 Co 0. Mg} 0.05] O 1.9 F _0.1 of the Comparative Example _{3 Li [Ni 0.4 Mn 0.4 Co} 0.2] O 2 4.6V after charging differential thermal Results of gravimetric analysis (DSC).

The present invention relates to a cathode active material for a lithium secondary battery having high capacity and high safety. Li-ion secondary batteries have been widely used as power sources for portable devices since they emerged in 1991 as small, light and large capacity batteries. Recently, with the rapid development of electronics, telecommunications, and computer industry, camcorders, mobile phones, notebook PCs, etc. have emerged and are developing remarkably, and the demand for lithium ion secondary battery as a power source to drive these portable electronic information communication devices is increasing day by day. It is increasing. In particular, research on power sources for electric vehicles by hybridizing an internal combustion engine and a lithium secondary battery has been actively conducted in the United States, Japan, and Europe. As a large-sized battery for an electric vehicle, it is still in the beginning of development and in particular, a nickel hydrogen battery is used in terms of safety, but the use of a lithium ion battery is considered in terms of energy density, but the biggest problem is high price and safety. In particular, both LiCoO ₂ and LiNiO ₂ cathode active materials that are currently commercially available have a disadvantage in that their thermal properties are very poor due to unstable crystal structure due to de-lithography during charging. In other words, when a battery in an overcharged state is heated to 200 to 270 ° C, a drastic structural change occurs, and an oxygen release reaction in the lattice due to such a structural change proceeds (JRDahn et al., Solid State Ionics, 69,265 (1994). )).

Commercially available small lithium ion _secondary batteries use LiCoO ₂ for the positive electrode and carbon for the negative electrode. LiCoO ₂ is an excellent material having stable charging and discharging characteristics, excellent electronic conductivity, high stability, and flat discharge voltage characteristics. However, since Co is low in reserve and expensive and toxic to humans, it is desirable to develop other cathode materials. LiNiO ₂ having a layered structure such as LiCoO ₂ exhibits a large discharge capacity but has not been commercialized due to problems in cycle life, thermal instability, and safety at high temperatures. In order to improve this, an attempt is made to move a part of nickel to a transition metal element to shift the exotherm starting temperature to a higher temperature side or to broaden the exothermic peak to prevent a sudden exotherm (T.Ohzuku et al., J.). Electrochem.

There are many known techniques related to the production of Li-Ni-Mn-based composite oxides in which a part of Ni sites are substituted with Mn or Li-Ni-Mn-Co-based composite oxides substituted with Mn and Co. For example, Japanese Patent No. 8-171910 discloses mixing an alkali solution in a mixed aqueous solution of manganese and nickel to coprecipitate manganese and nickel, mixing lithium hydroxide in the coprecipitation mixture, and then calcining to form LiNi _x Mn _1-x O ₂ (0.7 A method of producing a positive electrode active material of ≤ x ≤ 0.95 has been proposed. Recently, Japanese Patent No. 2000-227858 discloses a novel concept of a positive electrode active material by making a solid solution by uniformly dispersing nickel and manganese compounds at atomic level, rather than partially substituting a transition metal to LiNiO ₂ or LiMnO ₂ .

Recently, Li [Ni _1/2 Mn _1/2 ] O ₂ and Li [Ni in which nickel-manganese and nickel-cobalt-manganese are mixed 1: 1 with a layered crystal structure most popular as a substitute for LiCoO ₂ . _1/3 Co _1/3 Mn _1/3 ] O ₂ , and the like. The materials and exhibit characteristics such as low cost, high capacity and excellent thermal stability as compared to LiCoO _2, and due to the low electronic conductivity than LiCoO ₂ poor high rate characteristics and low-temperature properties, despite the capacity high due to low tap density The energy density of the battery does not improve. In particular, these materials have low electron conductivity (J. of Power Sources, 112 (2002) 41-48), which are less powerful than LiCoO ₂ or LiMn ₂ O ₄ for use as hybrid power sources for electric vehicles. Common methods, such as Li [Ni _1/2 Mn _1/2 ] O ₂ and Li [Ni _1/3 Co _1/3 Mn _1/3 ] O ₂ , are used to neutralize two or three elements simultaneously using neutralization in an aqueous solution. Precipitation is carried out to obtain a precursor in the form of a hydroxide or oxide, which is mixed with lithium hydroxide and calcined. Unlike conventional coprecipitation reactions, coprecipitation particles containing manganese usually exhibit irregular platelets, and the tap density is only about half that of nickel or cobalt. For example, Japanese Patent Application Laid-Open No. 2002-201028 used a conventional reactor by an inert precipitation method, wherein the produced precipitated particles have a very large particle size distribution and the shape of primary particles varies from particle to particle. More recently, Japanese Patent Application Nos. 2003-238165, 2003-203633, 2003-242976A, 2003-197256A, 2003-86182, 2003-86182, 2003-68299 and 2003-59490, and 10-2003-0026826 and 10-2003 In -0084702, nickel and manganese salts or nickel, manganese and cobalt salts are dissolved in an aqueous solution, and then an alkali solution is simultaneously introduced into the reactor to purge with a reducing agent or an inert gas to obtain metal hydroxides and oxides, and the precursors BACKGROUND ART A technique for preparing a high capacity positive electrode active material having improved charge / discharge reversibility and thermal stability by mixing after firing is known.

_{Li [Ni 1/2 Mn 1/2] O} 2 and _{Li [Ni 1/3 Co 1/3 Mn 1/3} ] O 2 and the like (0.0≤x≤1.0 in LiNi _x Co _1-2x Mn _x O ₂ In one form, Ni is divalent, Co is trivalent, and Mn is tetravalent. Therefore, there is no structural transition due to Jahn-Teller distortion caused by Mn trivalent. Oxidation / reduction species due to desorption of lithium during charging is known as Ni ²⁺ / Ni ⁴⁺ , Co ³⁺ / Co ⁴⁺ . It is necessary to increase the amount of Ni and Co, the active species of this electrochemical reaction, while fixing the oxidation number of Mn to 4+ to enable high capacity material synthesis. Recently in PCT / JP2004 / 012015, LipNixCoyMnzMqO2-aFa substituted with F in the transition metal layer-based compound (0.9≤p≤1.1, 0.2≤x≤0.8, 0≤y≤0.4, 0≤z≤0.5, y + Z> 0 , 0 ≦ q ≦ 0.05, 1.9 ≦ 2-a ≦ 2.1, 0 ≦ a ≦ 0.02, x + y + z + q = 1). The material is fluorine substituted for bulk energy density, thermal safety and Lifespan characteristics are greatly improved. However, this patent does not substitute M from the time of preparation of the precursor at the time of M substitution, but instead prepares Ni, Co, and Mn hydroxides such as (Ni 1/3 Co 1/3 Mn 1/3) (OH) 2 and then dry M Since it is substituted, it does not substitute to bulk but distributes only to the particle surface, and it does not contribute to the structural stability of the whole particle | grain. In addition, when fluorine is substituted in the oxygen site, the charge balance (balancing) of the positive and negative ions of the positive electrode active material is not matched, and thus the oxygen is insufficient or the electrochemical properties are reduced. Recently disclosed Korean Patent 10-2003-0084702 is known to have the effect of improving the thermal stability, life characteristics and high rate characteristics of the lithium transition metal composite oxide through F substitution.

In order to solve the above problems, the present invention controls the oxidation state of nickel, manganese and cobalt elements using carbonate or hydroxide coprecipitation method, and maintains the charge balance of positive and negative ions through Mg element and anion substitution. It is an object of the present invention to provide a high capacity positive electrode active material having improved tab density and thermal safety and high rate characteristics. The lithium transition metal composite oxide proposed in the present invention is based on Ni having divalent oxidation number, Co having trivalent oxidation number, and Mn having tetravalent oxidation number as a basic composition. It is added during the preparation of the precursor to evenly distribute throughout the powder particles. At this time, in order to improve the tap density of the positive electrode active material, lifetime and high rate characteristics, and thermal safety, fluorine is added to the oxygen site in order to maintain the charge balance of positive and negative ions in consideration of the positive and negative ions substituted and added to the oxygen site. It provides an active material.

In addition, another lithium transition metal composite oxide proposed in the present invention is Ni having a divalent oxidation number, Co having a trivalent oxidation number, and Mn having a tetravalent oxidation number in order to improve life characteristics, high rate characteristics, thermal safety, and increase tap density. In order to balance the overall charge balance between the cation and the anion by using a basic composition, at least one or more of divalent ions Mg, Cu, Zn, Ge, and Sn are substituted at the Mn site of the positive electrode active material, and fluorine (O) is substituted at the oxygen (O) site. F), where the divalent metal substituted at the Mn site serves to prevent cation mixing between the cations and the fluorine substituted at the oxygen site protects the surface from hydrofluoric acid (HF) in the electrolyte, The present invention was completed by knowing that the crystal structure can be stabilized.

In order to achieve the above object, according to the present invention, the aqueous ammonia solution (NH ₄ OH) and ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), ammonium hydrogen carbonate (NH ₄ HCO ₃ ), sodium carbonate (Na ₂ CO ₃ ) And obtaining a precipitate of the metal complex carbonate or the metal complex hydroxide mixture by reacting the mixed solution by adding an aqueous solution of a sodium hydroxide (NaOH) solution, a metal aqueous solution, and a carbon dioxide gas or nitric acid gas, and heat treating the precipitate. A method of manufacturing a lithium secondary battery positive electrode active material comprising the steps of obtaining an oxide and obtaining a lithium metal composite oxide of the following Chemical Formula 1 by mixing the metal composite hydroxide or the metal composite oxide with lithium hydroxide and lithium fluoride Is provided.

 [Formula 1]

Li _δ [Ni _{x + z} Co _{1-2x + z '} Mn _{x- (z + z')} ] O _{2-2z-z '} F _{2z + z'} (0.9≤δ≤1.15, 0.01≤x≤0.5, 0.01 ≤ z, z '≤ 0.15, x> z + z`)

According to the present invention, a metal salt aqueous solution containing M (at least one element selected from M = Mg, Ca, Sr, Zn, and Cu) is added to the metal aqueous solution to obtain a lithium metal complex oxide of Formula 2 A method for producing a lithium secondary battery positive electrode active material is provided.

[Formula 2]

Li _δ [Ni _{x + y} Co _1-2x-y Mn _xz M _z ] O _{2- (y + 2z)} F _{(y + 2z)} (M = Mg, Ca, Sr, Zn, Cu at least one selected from Element of, 0.9≤δ≤1.15, 0.16≤x≤0.42, 0.01≤y≤0.15, 0.01≤z≤0.15)

The aqueous metal solution is characterized in that at least one metal salt solution of the aqueous solution of sulphate, nitrate solution, aqueous fluoride solution and aqueous chloride solution.

The concentration of the aqueous ammonia solution is 5% to 40% of the concentration of the aqueous metal salt solution provides a method for producing a lithium secondary battery positive electrode active material.

The aqueous solution of ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), ammonium hydrogen carbonate (NH ₄ HCO ₃ ), sodium carbonate (Na ₂ CO ₃ ) and sodium hydroxide (NaOH) aqueous solution concentration of the aqueous solution It is characterized in that 100% to 200% of.

* The residence time of the metal aqueous solution in the reactor is characterized in that 5 to 20 hours.

The mixed solution is characterized in that pH 7.0 to 11.5.

In the production method of the present invention, the reactor is a rotor blade designed in reverse wing type and provided with a cylinder inside the reactor, characterized in that the reactor of the structure 1 to 4 baffles (spaced apart from the inner wall).

In the present invention, a method for producing a lithium secondary battery cathode active material, characterized in that further adding any one of citric acid, tartaric acid, glycolic acid and maleic acid as a chelating agent in the step of obtaining the lithium metal composite oxide.

In the present invention, there is provided a lithium secondary battery positive electrode active material, which is represented by the following Chemical Formula 1 as manufactured by the above-described method.

[Formula 1]

Li _δ [Ni _{x + z} Co _{1-2x + z '} Mn _{x- (z + z')} ] O _{2-2z-z '} F _{2z + z'} (0.9≤δ≤1.15, 0.01≤x≤0.5, 0.01 ≤ z, z '≤ 0.15, x> z + z`)

In addition, there is provided a lithium secondary battery positive electrode active material, characterized in that represented by the formula (2).

[Formula 2]

Li _δ [Ni _{x + y} Co _1-2x-y Mn _xz M _z ] O _{2- (y + 2z)} F _{(y + 2z)} (M = Mg, Ca, Sr, Zn, Cu at least one selected from Element of, 0.9≤δ≤1.15, 0.16≤x≤0.42, 0.01≤y≤0.15, 0.01≤z≤0.15)

The lithium secondary battery positive electrode active material is characterized in that the secondary particles having a layered rock salt structure having a particle diameter of 5 to 15㎛ composed of agglomeration of primary particles having a particle diameter of 10 to 30nm.

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

The lithium secondary battery positive electrode active material of the present invention increases the amount of oxidation / reduction species due to the insertion and desorption of lithium in the lithium transition metal composite oxide, makes the cation deficient, and then, in order to balance charge with the cation Minimize cation substitution by replacing fluorine in oxygen site or divalent metal in Mn site, and maintain the balance of cation and anion charge to maintain thermal safety, lifetime and high rate characteristics of lithium transition metal complex oxide. It is an improvement.

It is preferable that the specific target of the lithium metal composite oxide which is a positive electrode active material in this invention is 3 m <2> / g or less. If the specific target is 3 m 2 / g or more, the reactivity with the electrolyte is increased and gas generation is increased, so the specific surface area is preferably 3 m 2 / g or less.

In the present invention, the amount of fluorine contained in the lithium transition metal composite oxide is preferably 0.01 to 0.1 mol based on 1 mol of oxygen. If the amount of fluorine is too small, there is no effect of improving the lifetime and thermal safety. If the amount of fluorine is too high, the reversible capacity decreases and discharge characteristics are inferior.

The preparation method of the lithium metal composite oxide of the present invention represented by the above formula is ammonia aqueous solution (NH ₄ OH), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), ammonium hydrogen carbonate (NH ₄ HCO ₃ ), sodium carbonate (Na ₂ CO ₃₎ ) And the aqueous solution of sodium hydroxide (NaOH) solution and the metal aqueous solution and carbon dioxide gas or nitrogen gas to react to obtain a precipitate of the metal complex hydroxide or metal complex carbonate, the precipitate is dried or heat treated to the metal complex Obtaining an oxide and calcining the metal complex hydroxide or the metal complex oxide at a high temperature after mixing the lithium salt to obtain a lithium metal complex oxide.

In addition, in the present invention, a method of preparing a positive electrode active material is different from a batch type in which ammonia water and an aqueous solution of ammonium carbonate are mixed in a metal solution and then precipitated. ₄ ) Precipitating the uniformity of particles and uniform distribution of metal elements by preventing the initial oxidation of metal ions by simultaneously injecting ₂ CO ₃ ), ammonium hydrogen carbonate (NH ₄ HCO ₃ ) and sodium carbonate into the reactor. Can be obtained continuously. Here, the aqueous ammonia solution is a source of ammonium ions. The ammonium ion is required to generate a seed metal ammonium complex ion, and it is important to control the amount thereof, and it is preferable to use a concentration of 5% to 40% of the aqueous metal salt concentration. This means that if the ammonium ion is less than 5% of the metal salt concentration, the metal ammonium complex ion cannot be formed, and if it exceeds 40%, the nickel and cobalt ammonium complex ions are dissolved by the accumulation of excess ammonium ions to control the precise composition of the final product. Because it is impossible.

At this time, the metal aqueous solution is preferably used as a salt solution of sulphate, nitrate solution, fluoride solution and aqueous chloride solution of at least one metal salt concentration of 1M to 3M. In addition, it is preferable to use the sodium carbonate aqueous solution in the same molar ratio as a metal salt aqueous solution or a slightly excess concentration.

In addition, the method for producing a cathode active material in the present invention, unlike the ammonia complex method (Ammonia complex method) in which ammonia water is first mixed with the existing metal solution and then precipitated, two or more types of metal aqueous solution, aqueous ammonia solution, and sodium carbonate (Na ₂ CO ₃ ) aqueous solution. By respectively putting in the reactor and maintaining a carbonic acid atmosphere, it is possible to prevent the initial oxidation of manganese ions to obtain a precipitate uniformly distributed particles and metal elements uniformly. The metal solution is 2M, and to the use of 3M concentration, ammonia water solution is the concentration of a range from 0.2 to 0.4 in the metal solution concentration, Na ₂ CO ₃ aqueous solution is preferable to wind the used concentration of 1M to 3M. The concentration of the aqueous ammonia solution is 0.2 or more and 0.4 or less of the concentration of the aqueous metal solution because the ammonia reacts with the metal precursor one-to-one, but the intermediate product can be recovered and used again as ammonia, which further increases and stabilizes the positive electrode active material crystallinity. It is because it is an optimal condition for doing so.

Specifically, first, nickel, manganese, cobalt and substituted metal salts are dissolved in distilled water, and then introduced into the reactor together with aqueous ammonia solution and aqueous NaOH or Na ₂ CO ₃ solution. The coprecipitation method is a method of obtaining a composite hydroxide by simultaneously precipitating two or more elements by using a neutralization reaction in an aqueous solution. After the reactor reaches steady state, the composite hydroxide is continuously obtained through an overflow pipe installed at the top of the reactor. The average residence time of the solution was adjusted to 5-20 hours, the pH was maintained at 7.0-11.5 and the reactor temperature was maintained at 40-55 ° C. The reason for raising the temperature of the reactor is that it is difficult to obtain a high-density complex hydroxide because the cobalt hydroxide produced is precipitated in complex salt form at a low temperature. The obtained composite hydroxide was washed with distilled water, filtered and dried at 110 ° C. for 15 hours, or heat treated at 500 ° C. for 10 hours to be used as a precursor. The obtained precursor was sufficiently mixed with lithium hydroxide, calcined at 900 ° C. for 20 hours, and then annealed at 700 ° C. for 10 hours to prepare a lithium metal composite oxide.

The present invention provides a lithium secondary battery cathode active material, which is, in one embodiment, nickel oxide is 2.0, manganese oxide is 4.0, cobalt oxide is 3.0.

Cathode active material according to the present invention is Li _δ [Ni _{x + z} Co _{1-2x + z '} Mn _{x- (z + z')} ] O _{2-2z-z '} F _{2z + z'} (0.9≤δ≤1.15, 0.01≤x≤0.5, 0.01≤z, z'≤0.15, x> z + z`) or Li _δ [Ni _{x + y} Co _1-2x-y Mn _xz M _z ] O _{2- (y + 2z)} F _{(y + 2z)} (M = at least one element selected from Mg, Ca, Sr, Zn, Cu, 0.9≤δ≤1.15, 0.16≤x≤0.42, 0.01≤y≤0.15, 0.01≤z≤0.15), and primary particles are aggregated to form secondary particles. At this time, the average particle diameter of a primary particle is 10-30 nm, and the average particle diameter of a secondary particle is 5-15 micrometers, It is characterized by the above-mentioned. The average particle diameter of the primary particles is 10 to 300 nm to increase the reactivity of charging and discharging to improve high rate characteristics, while the average particle diameter of the secondary particles is 5 to 15 μm, preferably 10 μm. It is possible to increase the capacity of the electrode by increasing the filling property of the metal complex oxide and improving the coating power. In addition, by containing a small amount of fluorine in the positive electrode active material of the present invention, the thermal safety and lifespan characteristics are significantly improved.

1 is a cross-sectional view of a reactor used in the method of manufacturing a cathode active material of the present invention. The reactor has a rotor blade designed in reverse wing type, and has 1 to 4 baffles spaced 2 to 3 cm apart from the inner wall, and these baffles are used to uniformly mix the upper and lower parts of the reactor. Installed. The reverse wing design is also designed for uniform mixing up and down, and the separation of the baffles installed on the inner surface of the reactor from the inner wall controls the intensity and direction of the waves and increases the turbulent effect to solve the local nonuniformity of the reaction solution. It is to.

In the case of using the reactor, the tap density of the obtained carbonate and hydroxide was improved by about 10% or more than in the case of using the conventional reactor. The tap density of the preferred carbonates and hydroxides in the present invention is 1.6 g / cm 3, particularly preferably 2.1 g / cm 3 or more, and more preferably 2.3 g / cm 3.

The coprecipitation method is a method of obtaining complex carbonate by simultaneously depositing two or more elements by using a neutralization reaction in an aqueous solution. To this end, in the present invention, first, an aqueous solution of nickel, manganese, cobalt, and substituted metal salts is added to an aqueous solution of ammonia and ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), ammonium bicarbonate (NH ₄ HCO ₃ ), and sodium carbonate (Na ₂ CO ₃ ). It is added to the reactor with either solution. At this time, the reactor is purged with bubbling carbon dioxide gas to prevent oxidation of manganese ions and at the same time, carbonate ions which may be insufficient during the precipitation reaction are supplied to the reactor.

After the reactor reaches a steady state, metal composite carbonate is continuously obtained through an overflow pipe installed at the top of the reactor. The average residence time of the solution was adjusted to 5 to 20 hours, the pH was 7.0 to 11.5 and the reactor temperature was maintained at 30 ℃ to 60 ℃. The obtained metal composite carbonate was washed with distilled water and then filtered and dried at 110 ° C. for 15 hours, or after heat treatment at 500 ° C. for 10 hours.

The obtained metal complex hydroxide or metal complex oxide is sufficiently mixed with lithium hydroxide, calcined at 900 ° C. for 20 hours, and then annealed at 700 ° C. for 10 hours to produce a lithium metal complex oxide.

Provided by the present invention is a lithium secondary battery positive electrode active material, characterized in that represented by the formula (1).

[Formula 1]

Li _δ [Ni _{x + z} Co _{1-2x + z '} Mn _{x- (z + z')} ] O _{2-2z-z '} F _{2z + z'} (0.9≤δ≤1.15, 0.01≤x≤0.5, 0.01 ≤ z, z '≤ 0.15, x> z + z`)

In addition, there is provided a lithium secondary battery positive electrode active material, characterized in that represented by the formula (2).

[Formula 2]

Li _δ [Ni _{x + y} Co _1-2x-y Mn _xz M _z ] O _{2- (y + 2z)} F _{(y + 2z)} (M = Mg, Ca, Sr, Zn, Cu at least one selected from Element of, 0.9≤δ≤1.15, 0.16≤x≤0.42, 0.01≤y≤0.15, 0.01≤z≤0.15)

The lithium secondary battery positive electrode active material is characterized in that the secondary particles having a layered rock salt structure having a particle diameter of 5 to 15㎛ composed of agglomeration of primary particles having a particle diameter of 10 to 30nm.

It is possible to provide a lithium secondary battery using the cathode active material according to the present invention. Examples of electrolytes that may be used in the lithium secondary battery include esters such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and Cyclic carbonates such as vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and Acyclic carbonates such as Zipurofilcarbonone (DPC), methyl formate (methyl) IMF, methyl acetate (MA), methyl propionate (MP) and ethyl propionate (MA) And cyclic carboxylic acid esters such as aliphatic carboxylic acid esters and butyl lactones (GBL). As cyclic carbonate, EC, PC, VC, etc. are especially preferable. Moreover, it is also preferable to contain aliphatic carboxylic acid ester in 20% or less of range as needed.

Lithium salts dissolved in these solvents include LiClO₄, LiBF₄, LiPF ₆ , LiAlCl ₄ , LiSbF ₆ , LiSCN, LiCF ₃ SO₃, LiCF ₃ CO₂, Li (CF ₃ SO₂) ₂, LiAsF ₆ , LiN (CF ₃ SO₂) ₂ , LiB ₁₀ Cl ₁₀ , Lithium Bis (oxalato) borate (LiBOB), lower aliphatic lithium carbonate (Lithium), chloro borane Lithium, lithium tetraphenyl borate (Lithium), LiN (CF ₃ SO ₂ ) ( Imides such as C ₂ F ₅ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂, LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) And the like. These may be used alone or in any combination within the ranges which do not impair the effects of the present invention, either alone or in the electrolytic solution to be used. Among them, it is particularly preferable to include LiPF ₆ . In order to render the electrolyte incombustible, carbon tetrachloride, ethylene trifluoride (ethylene), or phosphate containing phosphorus may be included in the electrolyte.

Moreover, a solid electrolyte can also be used as follows. Inorganic solid electrolytes include Li ₄ SiO ₄ , Li ₄ SiO ₄ -Lil-LiOH, xLi ₃ PO _4- (1-x) Li ₄ SiO ₄ , Li ₂ SiS ₃ , Li ₃ PO ₄ -Li ₂ S-SiS ₂ And phosphorus sulfide compounds are effective. Organic solid electrolytes include polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyvinylidene, fluoropropylene, and polymer materials such as derivatives, mixtures, and composites. Valid.

The separator mainly uses a polyethylene-based or polypropylene-based polymer such as porous polyethylene.

As the negative electrode material used in the present invention, lithium ions such as lithium, lithium alloy, alloy, intermetallic compound, carbon, organic compound, inorganic compound, metal complex and organic polymer compound can be occluded and released. It may be a compound. These may be used alone or in any combination, either alone or in a range that does not impair the effects of the present invention. Examples of lithium alloys include Li-Al alloys, Li-Al-Mn alloys, Li-Al-Mg alloys, Li-Al-Sn alloys, Li-Al-In alloys, and Li-Al-Cd. Alloys, Li-Al-Te alloys, Li-Ga alloys, Li-Cd alloys, Li-In alloys, Li-Pb alloys, Li-Bi alloys and Li-Mg alloys have. As an alloy and an intermetallic compound, the compound of a transition metal and silicon, the compound of a transition metal, and tin, etc. are mentioned, Especially a compound of nickel and silicon is preferable. Examples of carbonaceous materials include coke, pyrolytic carbon, natural graphite, artificial graphite, meso carbon micro beads, graphitized meso phase small spheres, vapor grown carbon, glassy carbon, and carbon fiber. (Poly acrylonitrile-based, pitch-based, cellulose-based, vapor-grown carbon-based), amorphous carbon, and carbon from which organic materials are fired. Each of these may be used alone or in any combination within a range that does not impair the effects of the present invention. In addition, a packaging material composed of a metal can or aluminum and several layers of polymers is mainly used as the exterior material.

Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples.

Example 1

After putting 4 liters of distilled water into the reactor of FIG. Stirring at 1000 rpm while maintaining the temperature of the reactor at 60 ℃.

Nickel sulfate, manganese sulfate, and cobalt sulfate were continuously added to the reactor at a ratio of 0.33 / 0.35: 0.22 in 2M metal aqueous solution at 0.3 liters / hour and 0.2M ammonia solution at 0.4 liters / hour in the reactor. . A 2 M sodium carbonate solution was supplied for pH adjustment, maintaining the pH at 7.5.

Impeller speed was adjusted to 1000 rpm. The average residence time of the solution was adjusted to a flow rate of about 6 hours, and after the reaction reached a steady state, spherical nickel manganese cobalt composite carbonate was continuously obtained through an overflow pipe. The obtained metal composite carbonate was filtered and washed with water and then dried in a 110 ° C. hot air dryer for 12 hours, and heat-treated at 500 ° C. for 10 hours to obtain a precursor in the form of a metal composite oxide.

In order to replace fluorine, a mixture of a metal composite oxide and a lithium hydroxide / lithium fluoride (LiOH · H ₂ O: LiF = 0.930 : 0.070) was mixed at a molar ratio of 1: 1.15, and then heated at a temperature of 1 ° C./min, and then 450 ~ Pre-firing was performed at 500 ° C. for 5 hours, followed by firing at 900 ° C. for 20 hours, followed by heat treatment in the manner described above to obtain Li [Ni _0.43 Co _0.22 Mn _0.35 ] O _1.92 F _0.08 cathode active material powder.

The amount of fluorine in the synthesized Li [Ni _0.43 Co _0.22 Mn _0.35 ] O _1.92 F _0.08 was analyzed by ion chromatography after dissolving the positive electrode active material in acid, which contained about 0.078 fluorine to the oxygen molar ratio close to the design value.

Comparative Example 1

The precursor and the lithium hydroxide mixture obtained in the same manner as in Example 1 were mixed at a molar ratio of 1: 1.15, and then heated at a temperature of 1 ° C./min, followed by preliminary firing by holding at 450˜500 ° C. for 5 hours. Baking at 20 ° C. for 20 hours yielded a Li [Ni _0.43 Co _0.22 Mn _0.35 ] O ₂ powder.

FIG. 2 is a photograph of the metal composite oxide FE-SEM heat-treated at 500 ° C. of Example 1, and FIG. 3 is Li [Ni _0.43 Co _0.22 Mn _0.35 ] O _1.92 F _0.08 of Example 1 and Li [Ni _0.43 of Comparative Example 1; Co _0.22 Mn _0.35] is a 3000-fold FE-SEM picture of the O _2. The lithium metal composite oxide powder of Example 1 has a spherical powder having an average particle diameter of 16 µm and a very uniform particle size distribution. The surface of the lithium metal composite oxide powder is composed of minute primary particles having a particle size of about 1 µm or less. Could.

4 is an X-ray diffraction pattern of the fluorine-substituted lithium metal composite oxide of Example 1 and the fluorine of Comparative Example 1 not substituted. The lithium metal composite oxide of Example 1 was found to be a layered compound having hexagonal-NaFeO ₂ structure having a space group R-3m and excellent crystallinity.

Slurry was prepared by mixing acetylene black as a positive electrode active material and a conductive material prepared in Example 1 and Comparative Example 1 and polyvinylidene fluoride (PVdF) as a binder in a weight ratio of 80:10:10. The slurry was uniformly applied to a 20 μm thick aluminum foil, and vacuum dried at 120 ° C. to prepare a positive electrode. The prepared anode and lithium foil were used as counter electrodes, and a porous polyethylene membrane (Celgard ELC, Celgard 2300, thickness: 25 µm) was used as a separator, and ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1. A coin battery was prepared according to a commonly known manufacturing process using a liquid electrolyte in which LiPF ₆ was dissolved at a concentration of 1 M in a solvent. The manufactured coin battery was evaluated by charging and discharging up to 50 cycles using a electrochemical analyzer (Toyo System, Toscat 3100U) in a constant current mode of 20 mA per gram of positive electrode active material at 2.8 to 4.6 V potential region. .

As a result of performing the charge / discharge test up to 50 cycles, in case of Li [Ni _0.43 Co _0.22 Mn _0.35 ] O ₂ of Comparative Example 1, the capacity retention ratio was about 80% compared to the initial discharge capacity (198 mAh / g). In the case of 1 Li [Ni _0.43 Co _0.22 Mn _0.35 ] O _1.92 F _0.08 sample, the capacity of about 98% was maintained compared to the initial capacity of 194 mAh / g. This is shown in FIG.

6 shows Li [Ni _0.43 Co _0.22 Mn _0.35 ] O _1.92 F _0.08 of Example 1 and Comparative Example 1; It showed high rate discharge characteristics of Li [Ni _0.43 Co _0.22 Mn _0.35 ] O ₂ . The fluorine-substituted Li [Ni _0.43 Co _0.22 Mn _0.35 ] O _1.92 F _0.08 of Example 1 exhibited almost the same discharge characteristics as Li [Ni _0.43 Co _0.22 Mn _0.35 ] O ₂ of Comparative Example 1 at a low rate corresponding to a low current. It is seen that the discharge curve shows a good discharge capacity and a small internal resistance at a high rate at which a high discharge current is applied.

7 shows Li [Ni _0.43 Co _0.22 Mn _0.35 ] O _1.92 F _0.08 of Example 1 and Comparative Example 1; Differential Scanning Calolimeter (DSC) shows thermal stability of Li [Ni _0.43 Co _0.22 Mn _0.35 ] O ₂ . At this time, the sample was charged to 4.6V. In the case of the LiNi _0.43 Co _0.22 Mn _0.35 O ₂ electrode of Comparative Example 1, exothermic heat was started at 236 ° C., and the maximum exothermic peak was exhibited at 250 ° C., at which time the calorific value was 590 J / g. However, LiNi _0.43 Co _0.22 Mn _0.35 O _1.92 F _0.08 of Example 1 exhibited an exothermic peak at 272 ° C., which increased the onset of exotherm temperature by 36 ° C., and showed a maximum exothermic peak at 280 ° C., and the calorific value decreased about half by 350J / g.

Example 2

Spherical nickel manganese cobalt magnesium in the reactor of FIG. 1 in the same reactor as in Example 1 was mixed with a metal solution of 2M concentration of nickel sulfate, manganese sulfate, cobalt sulfate and magnesium sulfate in a ratio of 0.4: 0.36: 0.2: 0.04. Composite carbon dioxide was obtained continuously. The obtained metal composite carbonate was filtered and washed with water and then dried in a 110 ° C. hot air dryer for 12 hours, and heat-treated at 500 ° C. for 10 hours to obtain a precursor in the form of a metal composite oxide.

In order to replace fluorine, a mixture of a metal composite oxide and a lithium hydroxide / lithium fluoride (LiOH · H ₂ O: LiF = 0.930 : 0.070) was mixed at a molar ratio of 1: 1.15, and then heated at a temperature of 1 ° C./min, and then 450 ~ Preliminary firing was carried out at 500 ° C. for 5 hours, followed by 20 hours at 900 ° C. to obtain Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O _1.92 F _0.08 cathode active material powder.

The amount of fluorine in the synthesized Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O _1.92 F _0.08 was dissolved in a positive electrode active material in acid and analyzed by ion chromatography. there was.

Comparative Example 2

After mixing the precursor and lithium hydroxide mixture obtained in the same manner as in Example 2 in a 1: 1.15 molar ratio and heated at a temperature of 1 ℃ / min temperature rate, and preliminary firing was maintained at 450 ~ 500 ℃ 5 hours, followed by 900 Baking at 20 ° C. for 20 hours yielded a Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O ₂ positive electrode active material powder.

8 is a metal composite oxide FE-SEM picture of Example 2 heat-treated at 500 ℃, Figure 9 is Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O _1.92 F _0.08 of Example 2 and Li [ 3000 times FE-SEM photograph of Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O ₂ powder. The lithium metal composite oxide powder of Example 2 was a spherical powder having an average particle diameter of 12 μm and its particle size distribution was very uniform. In addition, it was found that the surface was composed of fine primary particle powder of about 1 μm or less.

10 is an X-ray diffraction pattern of Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O _1.92 F _0.08 of Example 2 and Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O ₂ of Comparative Example 2 to be. The lithium metal composite oxide was found to be a layered compound having hexagonal-NaFeO ₂ structure having a space group R-3m and excellent crystallinity.

Also, a coin battery was prepared in the same manner as in Example 1, and its characteristics were evaluated under the same conditions. As a result of performing charge / discharge test up to 50 cycles, Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O ₂ of Comparative Example 2 showed a capacity retention of about 95% compared to the initial discharge capacity (194 mAh / g). In the case of the sample of Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O _1.92 F _0.08 of Example 2, the capacity of about 100% of the initial capacity of 190 mAh / g was maintained. This is shown in FIG.

12 shows Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O _1.92 F _0.08 of Example 2 and Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O ₂ of Comparative Example 2; Differential Scanning Calolimeter (DSC) shows thermal stability. At this time, the sample was charged to 4.6V. In the case of the Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O ₂ electrode of Comparative Example 2, the exotherm started at 275 ° C. and showed the maximum exothermic peak at 280 ° C., at which time the calorific value was 2400 J / g. However, Li [Ni _0.4 Co _0.2 Mn _0.36 Mg _0.04 ] O _1.92 F _0.08 of Example 2 exhibited an exothermic peak at 310 ° C., which increased the onset of exotherm temperature by 35 ° C., and exhibited a maximum exothermic peak at 315 ° C. Half was 1300 J / g.

Example 3

After putting 4 liters of distilled water into the reactor of FIG. 1 (capacity 4L, the output of the rotary motor more than 80W), nitrogen gas was bubbled into the reactor at a rate of 0.6 liters / minute to remove dissolved oxygen. Stirring at 1000 rpm while maintaining the temperature of the reactor at 50 ℃.

Nickel sulfate, manganese sulfate, cobalt sulfate, and magnesium sulfate were mixed in an aqueous solution of 2.4 M concentration in a ratio of 0.4: 0.35: 0.2: 0.05 at 0.3 liters per hour, and 4.8 M ammonia solution at 0.05 liters per hour. Continuously into the reactor. A sodium hydroxide solution at a concentration of 4.8 M was supplied for pH adjustment, maintaining the pH at 11.

Impeller speed was adjusted to 1000 rpm. The average residence time of the solution was adjusted to a flow rate of about 6 hours, and after the reaction reached a steady state, spherical nickel manganese cobalt magnesium composite carbonate was continuously obtained through an overflow pipe. The obtained metal composite carbonate was filtered and washed with water and dried in a 110 ° C. hot air dryer for 12 hours, and was sufficiently mixed with LiF and LiOH.H ₂ O so that the molar ratio Li / (Ni + Co + Mn + Mg) = 1.05. The mixture thus obtained was heated at a temperature of 2 ° C./min, and then preliminarily calcined at 450 to 600 ° C. for 5 hours, followed by firing at 1000 ° C. for 10 hours, followed by annealing to 700 ° C. for 10 hours, and then at 2 ° C. / After cooling at a rate of min, Li [Ni _0.4 Mn _0.35 Co _0.2 Mg _0.05 ] O _1.95 F _0.05 was obtained, and an FE-SEM photograph of the powder was obtained. The amount of fluorine in the synthesized Li [Ni _0.4 Co _0.2 Mn _0.35 Mg _0.05 ] O _1.95 F _0.05 was dissolved in the positive electrode active material in acid and analyzed by ion chromatography. there was.

Comparative Example 3

The precursor and the lithium hydroxide mixture obtained in the same manner as in Comparative Example 1 were mixed at a molar ratio of 1: 1.15, and then heated at a temperature of 1 ° C./min, and then preliminarily baked at 450 to 500 ° C. for 5 hours, followed by 900. It baked at 20 degreeC for 20 hours, and obtained the Li [Ni _0.4 Co _0.2 Mn _0.4 ] O ₂ positive electrode active material powder.

13 is a 5000-fold FE-SEM photograph of Li [Ni _0.4 Co _0.2 Mn _0.35 Mg _0.05 ] O _1.9 F _0.1 metal composite oxide of Example 3 and Li [Ni _0.4 Co _0.2 Mn _0.4 ] O ₂ powder of Comparative Example 3 . The Li [Ni _0.4 Co _0.2 Mn _0.4 ] O ₂ powder of Comparative Example 3 was a spherical powder having an average particle diameter of 10 μm and its particle size distribution was very uniform. Li [Ni _0.4 Co _0.2 Mn _0.35 Mg _0.05 ] O _1.95 F _0.1 powder of Example 3 has a size of 10 μm for secondary particles and consists of 1 μm square particles. The surface of the particles was modified due to the addition of magnesium and fluorine, which is expected to reduce the specific surface area and reduce the reactivity with the electrolyte, resulting in surface stability.

FIG. 14 shows X-ray diffraction of Li [Ni _0.4 Co _0.2 Mn _0.35 Mg _0.05 ] O _1.9 F _0.1 metal complex oxide of Example 3 and Li [Ni _0.4 Co _0.2 Mn _0.4 ] O ₂ powder of Comparative Example 3. ) Pattern. The lithium metal composite oxide was found to be a layered compound having hexagonal-NaFeO ₂ structure having a space group R-3m and excellent crystallinity.

The powders of Example 3 and Comparative Example 3 were also manufactured in the same manner as in Example 1, and a coin battery was evaluated under the same conditions. As a result of performing charge / discharge test up to 50 cycles, Li [Ni _0.4 Co _0.2 Mn _0.4 ] O ₂ of Comparative Example 3 showed a capacity retention of about 87.5% compared to the initial discharge capacity (182 mAh / g), In the case of Li [Ni _0.4 Co _0.2 Mn _0.35 Mg _0.05 ] O _1.95 F _0.1 of 3, the capacity of about 95.4% was maintained compared to the initial capacity of 176 mAh / g. This is shown in FIG.

Figure 16 shows the differential thermal weight showing the thermal stability of Li [Ni _0.4 Co _0.2 Mn _0.35 Mg _0.05 ] O _1.9 F _0.1 metal composite oxide of Example 3 and Li [Ni _0.4 Co _0.2 Mn _0.4 ] O ₂ powder of Comparative Example 3 Analysis (DSC: Differential Scanning Calolimeter) results are shown. At this time, the sample was charged to 4.6V. In the case of the Li [Ni _0.4 Co _0.2 Mn _0.4 ] O ₂ electrode, the exotherm started at 210 ° C. and exhibited the maximum exothermic peak at 270 ° C. at this time, the calorific value was 4227 J / g. However, Li [Ni _0.4 Co _0.2 Mn _0.35 Mg _0.05 ] O _1.9 F _0.1 showed an exothermic peak at 290 ℃ and the calorific value was reduced by more than half by 1733J / g.

The cathode active material for a lithium secondary battery synthesized by the manufacturing method of the present invention has a high capacity and a high tap density, and improved high rate characteristics. In particular, the positive electrode active material prepared by the present invention has an advantage of excellent thermal stability when de-lithium, and by suppressing side reactions with the electrolyte solution by containing a fluorine element improves the life characteristics.

Claims (13)

Aqueous solution of ammonia and aqueous solution of ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), ammonium hydrogen carbonate (NH ₄ HCO ₃ ), sodium carbonate (Na ₂ CO ₃ ) and sodium hydroxide (NaOH) solution, metal aqueous solution and carbonic acid Obtaining a precipitate of the metal complex carbonate or metal complex hydroxide mixture by adding a gas or nitrogen gas to react the mixed solution, heat treating the precipitate to obtain a metal complex oxide, and the heat treated metal complex hydroxide or metal complex oxide A method of manufacturing a high capacity, high safety layered cathode active material for a lithium secondary battery, comprising the step of obtaining a lithium metal composite oxide of the general formula (1) by a reaction of mixing lithium hydroxide and lithium fluoride.  [Formula 1] Li _δ [Ni _{x + z} Co _{1-2x + z '} Mn _{x- (z + z')} ] O _{2-2z-z '} F _{2z + z'} (0.9≤δ≤1.15, 0.01≤x≤0.5, 0.01 ≤ z, z '≤ 0.15, x> z + z`) The method of claim 1, wherein the aqueous metal salt solution containing M (M = Mg, Ca, Sr, Zn, Cu) is added to the aqueous metal solution to obtain a lithium metal composite oxide of the formula (2) A method for producing a high capacity, high safety, layered cathode active material for a lithium secondary battery. [Formula 2] Li <sub>δ</sub> [Ni <sub>x + y</sub> Co <sub>1-2x-y</sub> Mn <sub>xz</sub> M <sub>z</sub> ] O <sub>2- (y + 2z)</sub> F <sub>(y + 2z)</sub> (M = Mg, Ca, Sr, Zn, Cu at least one selected from Element of, 0.9≤δ≤1.15, 0.16≤x≤0.42, 0.01≤y≤0.15, 0.01≤z≤0.15) The method of claim 1 or 2, wherein the metal aqueous solution is at least one metal salt solution of an aqueous sulfate solution, an nitrate solution, an aqueous fluoride solution, and an aqueous chloride solution. The method of manufacturing a high capacity high safety layered cathode active material for a lithium secondary battery according to claim 1 or 2, wherein the concentration of the aqueous ammonia solution is 5 to 40% of the concentration of the aqueous metal solution. The method of manufacturing a high capacity, high safety layered cathode active material for a lithium secondary battery according to claim 1 or 2, wherein the concentration of the sodium carbonate or aqueous sodium hydroxide solution is 100 to 200% of the concentration of the metal aqueous solution. The method for producing a high capacity, high safety layered cathode active material for a lithium secondary battery according to claim 1 or 2, wherein the metal aqueous solution has a residence time in the reactor of 5 to 20 hours. The method of manufacturing a high capacity, high safety layered cathode active material for lithium secondary batteries according to claim 1 or 2, wherein the mixed solution has a pH of 7.0 to 11.5. The reactor according to claim 1 or 2, wherein the rotor is designed in a reverse wing type, has a cylinder inside the reactor, and has a structure in which 1 to 4 baffles are spaced apart from the inner wall. Method for producing a high capacity high safety layered cathode active material for a lithium secondary battery. 3. The high capacity and high safety layered lithium secondary battery according to claim 1 or 2, wherein any one of citric acid, tartaric acid, glycolic acid and maleic acid is further added as a chelating agent in the step of obtaining the lithium metal composite oxide. Method for producing a positive electrode active material. A high capacity high safety layered cathode active material for a lithium secondary battery, which is prepared by the method according to claim 1 and is represented by the following Chemical Formula 1. [Formula 1] Li <sub>δ</sub> [Ni <sub>x + z</sub> Co <sub>1-2x + z '</sub> Mn <sub>x- (z + z')</sub> ] O <sub>2-2z-z '</sub> F <sub>2z + z'</sub> (0.9≤δ≤1.15, 0.01≤x≤0.5, 0.01 ≤ z, z '≤ 0.15, x> z + z`) A high capacity high safety layered cathode active material for a lithium secondary battery, which is prepared by the method according to claim 2 and is represented by the following Chemical Formula 2. [Formula 2] Li _δ [Ni _{x + y} Co _1-2x-y Mn _xz M _z ] O _{2- (y + 2z)} F _{(y + 2z)} (M = Mg, Ca, Sr, Zn, Cu at least one selected from Element of, 0.9≤δ≤1.15, 0.16≤x≤0.42, 0.01≤y≤0.15, 0.01≤z≤0.15) 12. The lithium secondary battery according to claim 10 or 11, wherein the lithium secondary battery positive electrode active material is lithium secondary particles having a layered rock salt structure having a particle diameter of 5 to 30 µm, which is formed by aggregation of primary particles having a particle diameter of 10 to 400 nm. High capacity, high safety layered cathode active material for secondary batteries. A lithium secondary battery positive electrode active material prepared by the method of any one of claims 1 to 2 and a lithium secondary battery using the same.

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