WO2019194609A1 - Method for manufacturing cathode active material for lithium secondary battery, cathode active material for lithium secondary battery, cathode, comprising same, for lithium secondary battery, and lithium secondary battery comprising same - Google Patents

Abstract

A method for manufacturing a cathode active material for a lithium secondary battery according to the present invention comprises the steps of: mixing a transition metal hydroxide comprising transition metals inclusive of nickel (Ni), cobalt (Co), and manganese (Mn), a lithium-containing raw material, and a doping raw material including at least one doping element selected from the group consisting of Al, Mg, Co, V, Ti, Zr, and W and subjecting the mixture to a first baking process to afford a lithium composite transition metal oxide doped with the doping element; and mixing the lithium composite transition metal oxide and at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr, and B and subjecting the mixture to a second baking process to produce a cathode active material for a lithium secondary battery, in which a coating layer comprising the coating element is formed on the lithium composite transition metal oxide, wherein the doping raw material and the coating raw material are fed so that the weight ratio of the doping element to the coating element ranges from 0.3 to 7 in the cathode active material for a lithium secondary battery.

Description

Method for manufacturing positive electrode active material for lithium secondary battery, positive electrode active material for lithium secondary battery, positive electrode for lithium secondary battery and lithium secondary battery comprising same

Citation with Related Applications

This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0039359 of April 4, 2018, and Korean Patent Application No. 10-2019-0031933 of March 20, 2019, and the Korean patent All content disclosed in the literature of the application is included as part of this specification.

Technical field

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

Recently, with the rapid spread of electronic devices using batteries such as mobile phones, notebook computers, and electric vehicles, the demand for small, lightweight, and relatively high capacity secondary batteries is rapidly increasing. In particular, the lithium secondary battery has attracted attention as a driving power source for portable devices because of its light weight and high energy density. Accordingly, research and development efforts for improving the performance of lithium secondary batteries have been actively conducted.

The lithium secondary battery is oxidized when lithium ions are inserted / desorbed from the positive electrode and the negative electrode in a state in which an organic electrolyte or a polymer electrolyte is charged between a positive electrode and a negative electrode made of an active material capable of intercalation and deintercalation of lithium ions. Electrical energy is produced by the reduction reaction.

Lithium cobalt oxide (LiCoO ₂ ) is mainly used as a positive electrode active material of a lithium secondary battery. In addition, lithium manganese oxides such as LiMnO _{2 having a} layered crystal structure and LiMn ₂ O _{4 having a} spinel crystal structure, and lithium nickel oxide (LiNiO ₂₎ ) Is also being considered.

Among the positive electrode active materials, LiCoO ₂ is most frequently used because of its excellent life characteristics and charging and discharging efficiency, but it has a disadvantage in that its price competitiveness is limited because the low temperature safety and cobalt used as a raw material are expensive materials due to resource limitations. Have.

Lithium manganese oxides such as LiMnO ₂ and LiMn ₂ O ₄ have the advantages of excellent thermal safety, low cost, and easy synthesis, but have a problem of small capacity, poor high temperature characteristics, and low conductivity.

In addition, although lithium nickel oxides such as LiNiO ₂ are relatively inexpensive and exhibit high discharge capacity, they exhibit rapid phase transition of the crystal structure due to the volume change accompanying charge and discharge cycles, and are stable when exposed to air and moisture. There is a problem that this is sharply lowered.

Therefore, recently, lithium composite transition metal oxides in which a part of nickel is substituted with other transition metals such as manganese and cobalt have been proposed as substitute materials. In particular, the lithium composite transition metal oxide containing nickel in a high content has the advantage that the cycle characteristics and capacity characteristics are relatively good, but even in this case, the cycle characteristics rapidly decrease when used for a long period of time, Problems such as swelling and deterioration of thermal safety due to low chemical stability have not been sufficiently solved.

Therefore, there is a high need for a positive electrode active material capable of solving thermal safety problems while exhibiting improved output and cycle characteristics.

[Preceding technical literature]

[Patent Documents]

Korean Patent Registration No. 10-1510940

One object of the present invention is to provide a method of manufacturing a cathode active material for a lithium secondary battery having improved capacity characteristics, cycle characteristics, and improved durability by controlling the content ratio of the doping element and the coating element of the cathode active material.

In addition, another object of the present invention is to provide a cathode active material for a lithium secondary battery having improved capacity characteristics, cycle characteristics, and improved durability by controlling the content ratio of the doping element and the coating element.

In addition, another object of the present invention is to provide a lithium secondary battery positive electrode and a lithium secondary battery including the above-described positive electrode active material for lithium secondary batteries.

The present invention is a group consisting of a transition metal hydroxide including a transition metal including nickel (Ni), cobalt (Co) and manganese (Mn), a raw material containing lithium and Al, Mg, Co, V, Ti, Zr and W Preparing a lithium composite transition metal oxide doped with the doping element by mixing a doping raw material including at least one doping element selected from the first baking treatment; And a coating raw material including the lithium composite transition metal oxide and at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr, and B, followed by a second calcination treatment to form the lithium composite transition metal oxide. Preparing a cathode active material for a lithium secondary battery in which a coating layer including the coating element is formed thereon, wherein a ratio of the weight of the doping element to the weight of the coating element in the cathode active material for lithium secondary battery is 0.3 to 7; Provided is a method of manufacturing a cathode active material for a lithium secondary battery, wherein the doping raw material and the coating raw material are added.

In addition, the present invention is at least one selected from the group consisting of transition metals including nickel (Ni), cobalt (Co) and manganese (Mn) and Al, Mg, Co, V, Ti, Zr and W doped therein A lithium composite transition metal oxide containing a doping element of; And a coating layer formed on the lithium composite transition metal oxide, the coating layer comprising at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr, and B. The ratio of the weight of a doping element is 0.3-7, The positive electrode active material for lithium secondary batteries is provided.

In addition, the present invention provides a cathode for a lithium secondary battery including the cathode active material for a lithium secondary battery described above.

In addition, the present invention provides a lithium secondary battery comprising the positive electrode for a lithium secondary battery described above.

The method of manufacturing a cathode active material for a lithium secondary battery of the present invention includes a doping and coating process by first and second firings, and the ratio of the weight of the doping element to the weight of the coating element in the cathode active material is adjusted to 0.3 to 7. Accordingly, it is possible to improve the high temperature life characteristics and resistance increase of the lithium composite transition metal oxide, in particular, the lithium composite transition metal oxide having a high nickel content, and to realize a high level of capacity characteristics and high temperature storage characteristics.

The terms or words used in this specification and claims are not to be construed as being limited to their ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

As used herein, the terms "comprise", "comprise" or "have" are intended to indicate that there is a feature, number, step, component, or combination thereof, that is, one or more other features, It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

As used herein, "%" means weight percent unless otherwise indicated.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely.

Manufacturing method of positive electrode active material for lithium secondary battery

Method for producing a cathode active material for a lithium secondary battery according to the present invention is a transition metal hydroxide, a lithium-containing raw material and Al, Mg, Co, including a transition metal containing nickel (Ni), cobalt (Co) and manganese (Mn) Preparing a lithium composite transition metal oxide doped with the doping element by mixing and firstly baking a doping raw material including at least one doping element selected from the group consisting of V, Ti, Zr, and W; And a coating raw material including the lithium composite transition metal oxide and at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr, and B, followed by a second calcination treatment to form the lithium composite transition metal oxide. Preparing a cathode active material for a lithium secondary battery in which a coating layer including the coating element is formed thereon, wherein a ratio of the weight of the doping element to the weight of the coating element in the cathode active material for lithium secondary battery is 0.3 to 7; The doping raw material and the coating raw material are added.

According to the method for manufacturing a cathode active material for a lithium secondary battery of the present invention, a cathode active material including a doping element doped therein and a coating element-containing coating layer coated on the surface may be manufactured by the first and second firing processes, and the coating The weight ratio of the element and the doping element is adjusted to a specific range, indicating high structural stability and thermal stability of the active material. Therefore, it is possible to exhibit excellent capacity expression and high temperature cycle characteristics of the battery, and in particular, it can exhibit excellent structural stability and thermal stability in nickel high content lithium composite transition metal oxide or lithium high content lithium composite transition metal oxide. Capacity expression, high temperature cycle characteristics can be realized.

Method for producing a cathode active material for a lithium secondary battery according to the present invention is a transition metal hydroxide, a lithium-containing raw material and Al containing at least two or more transition metals selected from the group consisting of nickel (Ni), cobalt (Co) and manganese (Mn) Doping element material comprising at least one doping element selected from the group consisting of Mg, Co, V, Ti, Zr and W is mixed and subjected to first firing to prepare a lithium composite transition metal oxide doped with the doping element It includes a step.

The transition metal hydroxide includes a transition metal including nickel (Ni), cobalt (Co) and manganese (Mn).

The transition metal hydroxide may be a high content nickel (High-Ni) transition metal hydroxide having a content of nickel (Ni) of 70 mol% or more among all the transition metal elements contained in the transition metal hydroxide. More preferably, the content of nickel (Ni) in the total transition metal element may be 75 mol% or more. As described in the present invention, the use of a transition metal hydroxide of high content nickel (High-Ni) having a content of nickel (Ni) of 70 mol% or more in the entire transition metal element may ensure higher capacity.

The transition metal hydroxide may be, for example, a compound represented by Formula 1 below.

[Formula 1]

Ni _a Co _b Mn _c (OH) ₂

In Formula 1, a + b + c = 1, 0.7 ≦ a <1, 0 <b ≦ 0.3, and 0 <c ≦ 0.3.

In the transition metal hydroxide of Chemical Formula 1, Ni may be included in an amount corresponding to a, for example, 0.7 ≦ a <1, more specifically 0.75 ≦ a <1. When the Ni content in the transition metal hydroxide of Formula 1 is 0.7 or more, the amount of Ni sufficient to contribute to charging and discharging in the cathode active material including the same may be ensured, thereby increasing the capacity of the battery.

In the transition metal hydroxide of Chemical Formula 1, Co may be included in an amount corresponding to b, that is, 0 <b ≦ 0.3. When the content of Co in the transition metal hydroxide of Formula 1 exceeds 0.3, there is a fear of increased cost. Considering the remarkable improvement of the charging and discharging efficiency according to the inclusion of Co, the Co may be included in a content of 0.05≤b≤0.2 more specifically.

In the transition metal hydroxide of Chemical Formula 1, Mn may ensure lifetime characteristics and structural stability. In consideration of such an effect, the Mn may be included in an amount corresponding to c, that is, 0 <c≤0.3. When c in the transition metal hydroxide of Formula 1 exceeds 0.3, there is a concern that the output characteristics and the charge / discharge efficiency of the battery may be lowered, and Mn may be included in an amount of 0.05 ≦ c ≦ 0.2.

The transition metal hydroxide may be co-precipitated with a metal solution containing at least two or more transition metal-containing raw materials selected from the group consisting of nickel (Ni) -containing raw materials, cobalt (Co) -containing raw materials and manganese (Mn) -containing raw materials. It can manufacture.

The nickel (Ni) -containing raw material may be, for example, nickel-containing acetates, nitrates, sulfates, halides, sulfides, hydroxides, oxides or oxyhydroxides. Specifically, Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ · 2Ni (OH) ₂ · 4H ₂ O, NiC ₂ O ₂ · 2H ₂ O, Ni (NO ₃ ) ₂ · 6H ₂ O, NiSO ₄ , NiSO ₄ · 6H ₂ O, fatty acid nickel salts, nickel halides Or a combination thereof, but is not limited thereto.

The cobalt-containing raw material may be cobalt-containing acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide or oxyhydroxide, and the like. Specifically, Co (OH) ₂ , CoOOH, Co (OCOCH ₃ ) _2. 4H ₂ O, Co (NO ₃ ) ₂ 6H ₂ O, Co (SO ₄ ) ₂ ㆍ 7H ₂ O or a combination thereof, but is not limited thereto.

The manganese (Mn) -containing raw material may be, for example, manganese-containing acetates, nitrates, sulfates, halides, sulfides, hydroxides, oxides, oxyhydroxides, or combinations thereof, specifically Mn ₂ O ₃ , MnO ₂ Manganese oxides such as Mn ₃ O ₄ and the like; Manganese salts such as MnCO ₃ , Mn (NO ₃ ) ₂ , MnSO ₄ , MnSO ₄ .H ₂ O, manganese acetate, dicarboxylic acid manganese salt, manganese citrate, fatty acid manganese salt; Manganese oxy hydroxide, manganese chloride or a combination thereof, but is not limited thereto.

The metal solution is an organic solvent capable of uniformly mixing nickel (Ni) -containing raw material, cobalt (Co) -containing raw material and / or manganese (Mn) -containing raw material with a solvent, specifically water or water (eg For example, it may be prepared by adding to a mixed solvent of alcohol or the like, or by mixing an aqueous solution of a nickel (Ni) -containing raw material, a cobalt (Co) -containing raw material and / or a manganese (Mn) -containing raw material. have.

The transition metal hydroxide may be prepared by co-precipitation reaction by adding an ammonium cation-containing complex forming agent and a basic compound to the metal solution.

The ammonium cation-containing complex former may be, for example, NH ₄ OH, (NH ₄ ) ₂ SO ₄ , NH ₄ NO ₃ , NH ₄ Cl, CH ₃ COONH ₄ , NH ₄ CO _3, or a combination thereof. It is not limited to this. On the other hand, the ammonium cation-containing complex forming agent may be used in the form of an aqueous solution, wherein a solvent may be a mixture of water or an organic solvent (specifically, alcohol, etc.) that can be mixed with water uniformly.

The basic compound may be a hydroxide of an alkali metal or an alkaline earth metal such as NaOH, KOH, or Ca (OH) ₂ , a hydrate thereof, or a combination thereof. The basic compound may also be used in the form of an aqueous solution, and as the solvent, a mixture of water or an organic solvent (specifically, alcohol, etc.) that can be uniformly mixed with water may be used. The basic compound is added to adjust the pH of the reaction solution, the pH of the metal solution may be added in an amount of 9 to 14.

Meanwhile, the coprecipitation reaction may be performed at a temperature of 25 ° C. to 70 ° C. under an inert atmosphere such as nitrogen or argon.

The lithium-containing raw material may be lithium-containing carbonate (for example, lithium carbonate), hydrate (for example, lithium hydroxide I hydrate (LiOH · H ₂ O), etc.), hydroxide (for example, lithium hydroxide, etc.), nitrate ( Examples thereof include lithium nitrate (LiNO ₃ ) and the like, chlorides (for example, lithium chloride (LiCl) and the like) and the like, and one or a mixture of two or more thereof may be used.

The doping raw material is a material which is mixed with the above-described transition metal hydroxide and lithium-containing raw material to be first baked and supplies a doping element to be doped in the positive electrode active material.

The doping raw material includes at least one doping element selected from the group consisting of Al, Mg, Co, V, Ti, Zr and W.

The doping element is doped inside the lithium composite transition metal oxide by the first firing to be described later, and the structural stability of the lithium composite transition metal oxide, in particular Ni high content lithium composite transition metal oxide and / or Li high content lithium composite transition metal oxide Thermal stability can be further improved.

The doping raw material is preferably at least one doping element selected from the group consisting of Zr, Co and Al, more preferably at least one doping element selected from the group consisting of Zr and Al, more preferably Zr Most preferably, Zr and Al may be included, and when the positive electrode active material or the lithium composite transition metal oxide is doped with the aforementioned doping element, the structural stability and the passion stability improvement effect of the active material are further improved.

The dose of the doping raw material may be appropriately adjusted in consideration of the content and content ratio of the doping element in the positive electrode active material to be described later.

The doping raw material may include at least one first doping element selected from the group consisting of Co and Zr and at least one second doping element selected from the group consisting of Al, Mg, V, and W. When the first doping element is used together with the second doping element, the capacity characteristics of the active material as well as the high temperature life characteristics may be further improved, and the output characteristics may also be improved by reducing the transfer resistance of lithium ions. The first doping element may be preferably Zr, and the second doping element may be preferably Al, thereby maximizing the aforementioned effects.

The doping raw material may include the first doping element and the second doping element in a weight ratio of 30:70 to 70:30, preferably 40:60 to 60:40, and in the above-described range, lithium The effect of reducing the movement resistance of the ions, improving the capacity and output according to the durability, and more preferably may be realized.

The transition metal hydroxide, the lithium-containing raw material and the doping raw material may be mixed and first calcined to produce a lithium composite transition metal oxide doped with the doping element.

By the first firing, the doping element is doped into the lithium composite transition metal oxide, so that the structural stability and thermal properties of the lithium composite transition metal oxide, in particular, Ni high content lithium composite transition metal oxide and / or Li high content lithium composite transition metal oxide Stability can be further improved to prevent the collapse of the active material structure, and the bonding force between the transition metal and oxygen is improved, thereby preventing oxygen desorption and improving electrolyte side reaction prevention. Accordingly, the lithium composite transition metal oxide according to the present invention can improve excellent capacity expression and high temperature cycle characteristics of the active material.

The lithium composite transition metal oxide may be a lithium composite transition metal oxide in which the ratio (Li / Me) of the number of moles of lithium (Li) to the total number of moles of the transition metal is 1 or more, and thus the content of doping elements and coating elements to be described later. Along with the ratio, the capacity characteristics and output characteristics of the battery can be improved.

Specifically, the lithium composite transition metal oxide may have a ratio of the number of moles of lithium (Li) to the total number of moles of the transition metal (Li / Me) of 1 to 1.15, more specifically 1.05 to 1.1. When (Li / Me) is in the above-mentioned range, it is good in terms of excellent capacity and output characteristics of the battery.

The first firing may be performed at 700 ° C to 900 ° C, more preferably at 730 ° C to 850 ° C, and most preferably at 750 ° C to 830 ° C. When the first firing temperature is in the above-described range, sufficient reaction of the mixture can be achieved and uniform growth of the particles is possible.

The first firing may be performed at the temperature for 6 hours to 15 hours, preferably 8 hours to 12 hours.

The first firing may be performed in an oxygen atmosphere. In this case, mass transfer and reactivity may be promoted to uniformly doping the cathode active material, and the amount of unreacted lithium remaining in the mixture may be reduced.

In the method of manufacturing a cathode active material for a lithium secondary battery of the present invention, in order to remove impurities or unreacted raw materials remaining in the prepared lithium composite transition metal oxide, washing the lithium composite transition metal oxide after the first firing is performed. It may further include.

The washing process can be used without limitation washing methods known in the art, specifically, may be performed by mixing the lithium composite transition metal oxide and water.

Method for producing a cathode active material for a lithium secondary battery according to the present invention is a mixture of a coating raw material containing the lithium composite transition metal oxide and at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr and B. And preparing a cathode active material for a lithium secondary battery in which a coating layer including the coating element is formed on the lithium composite transition metal oxide by performing a second baking treatment.

The method of manufacturing a cathode active material for a lithium secondary battery may form a coating layer including the coating element on a lithium composite transition metal oxide by further performing a coating layer forming process by a second firing in addition to a doping process. Accordingly, the chemical stability of the surface of the active material may be further improved, the structure collapse due to the instability of the active material may be prevented, and the movement of lithium ions may be facilitated to improve output characteristics. Specifically, the coating element contained in the coating layer may be oxidized preferentially to the transition metal in the lithium composite transition metal oxide, thereby effectively preventing side reactions of the lithium composite transition metal oxide and the electrolyte, and reducing the migration resistance of lithium ions. The rise can be prevented.

The coating raw material may include at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr and B, preferably at least one selected from the group consisting of Al, Co and B. It may include a coating element, more preferably may include at least one coating element selected from the group consisting of Al and B, more preferably includes a coating element of B, most preferably Al and B can do.

The coating raw material may include a first coating element including at least one selected from the group consisting of Mg, Co, Ti, Zr, and B and a second coating element consisting of Al. As the second coating element made of Al is used together with the first coating element as the coating raw material, the effect of preventing structural collapse of the active material through surface protection of the active material may be further improved. The first coating element may be at least one selected from the group consisting of Co and B, more preferably B.

The coating raw material may include the first coating element and the second coating element in a weight ratio of 30:70 to 70:30, preferably 40:60 to 60:40, and when in the above range Surface protection and structural stability of the effect can be more preferably implemented.

The coating raw material may be adjusted in consideration of the coating element content and content ratio when forming a coating layer on the lithium composite transition metal oxide.

The second firing may be carried out, for example, at 200 ° C to 500 ° C, preferably at 250 ° C to 400 ° C. When the second firing temperature is in the above-described range, smooth and sufficient formation of the coating layer is possible.

The second firing may be performed at a corresponding temperature for 3 hours to 12 hours, preferably 5 hours to 10 hours.

The second firing may be performed in an air or oxygen atmosphere, thereby facilitating material movement and reactivity, thereby enabling smooth formation of the coating layer.

In the method for producing a cathode active material for a lithium secondary battery according to the present invention, the ratio of the weight of the doping element to the weight of the coating element in the cathode active material for lithium secondary batteries is 0.3 to 7, preferably 0.4 to 4.5, more preferably The doping raw material and the coating raw material is added to be 0.6 to 4.3, most preferably 1.5 to 3.5.

When the ratio of the weight of the doping element to the weight of the coating element is less than 0.3, the coating layer may be excessively formed, thereby increasing the surface resistance of the positive electrode active material. Accordingly, the charge and discharge efficiency may decrease, and the output characteristics may be deteriorated. When the ratio of the weight of the doping element to the weight of the coating element is greater than 7, there is a fear of reducing the high temperature storage characteristics and durability due to the relatively excessive amount of doping, the charge and discharge capacity may be reduced.

The ratio of the weight of the doping element to the weight of the coating element according to the present invention is adjusted in consideration of the content of the coating element contained in the coating raw material to be added during the preparation of the positive electrode active material and the content of the doping element contained in the doping raw material Can be implemented.

In the method of manufacturing a positive electrode active material for a lithium secondary battery according to the present invention, the doping raw material so that the content of the doping element is 2,500ppm to 14,000ppm, preferably 3,000ppm to 9,000ppm with respect to the total weight of the positive electrode active material for lithium secondary battery. The substance can be added. When the doping raw material is added such that the doping element is doped in the lithium composite transition metal oxide in the above-described content range, structural stability and thermal stability improvement of the active material can be effectively realized. In addition, the phenomenon in which the charge / discharge capacity and the efficiency of the battery due to the excessive or excessive doping may be prevented.

In the method of manufacturing a cathode active material for a lithium secondary battery according to the present invention, the content of the coating element is 1,000 ppm to 9,400 ppm, preferably 1,500 ppm to 9,000 ppm, more preferably based on the total weight of the cathode active material for lithium secondary battery. The coating raw material may be added so as to be 1,500 ppm to 5,000 ppm. When in the above-described range can improve the structural stability of the active material, as well as increase the resistance due to excessive coating layer formation, it can prevent the effect of reducing the output.

The content of the doping element and / or coating element included in the cathode active material for a lithium secondary battery, and the content ratio thereof may be adjusted, for example, in consideration of the amount of the doping raw material and the coating raw material in preparation.

The above-described content or content ratio may be measured or calculated through, for example, inductively coupled plasma mass spectrometry (ICP-OES), but is not limited thereto.

The average particle diameter (D ₅₀ ) of the positive electrode active material for the lithium secondary battery may be 5 μm to 30 μm, preferably 10 μm to 20 μm, more preferably 14 μm to 18 μm, in the range of the active material rolling process. It is preferable from the viewpoint of the rollability and energy density improvement of the.

In the present invention, the average particle diameter (D ₅₀ ) may be defined as a particle size corresponding to 50% of the volume accumulation amount in the particle size distribution curve. The average particle diameter D ₅₀ may be measured using, for example, a laser diffraction method. For example, the measuring method of the average particle diameter (D ₅₀ ) of the positive electrode active material is dispersed in the dispersion medium particles in a dispersion medium, and then introduced into a commercially available laser diffraction particle size measuring apparatus (for example, Microtrac MT 3000) to After irradiating an ultrasonic wave of 28 kHz with an output of 60 W, an average particle diameter D ₅₀ corresponding to 50% of the volume accumulation amount in the measuring device can be calculated.

Cathode Active Material for Lithium Secondary Battery

The present invention also provides a cathode active material for a lithium secondary battery.

The cathode active material for a lithium secondary battery is at least one selected from the group consisting of transition metals including nickel (Ni), cobalt (Co) and manganese (Mn) and Al, Mg, Co, V, Ti, Zr and W doped therein. Lithium composite transition metal oxide containing one doping element; And a coating layer formed on the lithium composite transition metal oxide, the coating layer comprising at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr, and B. The ratio of the weight of a doping element is 0.3-7.

The positive electrode active material for a lithium secondary battery may be prepared according to the above-described method for preparing a positive electrode active material for a lithium secondary battery, a lithium composite transition metal oxide, a coating layer, and a manufacturing method, a component, and a content thereof doped with the doping element therein. As mentioned above.

The doping element is at least one selected from the group consisting of Al, Mg, Co, V, Ti, Zr and W, preferably at least one selected from the group consisting of Zr, Co and Al, more preferably Zr and Al At least one selected from the group consisting of, more preferably Zr, most preferably Zr and Al may be included, and when the above-mentioned doping element is included in the positive electrode active material, the structural stability and passion stability improvement effect of the active material is further Is improved.

The doping element may include at least one first doping element selected from the group consisting of Co and Zr and at least one second doping element selected from the group consisting of Al, Mg, V, and W. When the first doping element is used together with the second doping element, the capacity characteristics of the active material as well as the high temperature life characteristics may be further improved, and the output characteristics may also be improved by reducing the transfer resistance of lithium ions. The first doping element may be preferably Zr, and the second doping element may be preferably Al, thereby maximizing the aforementioned effects.

The doping element may include the first doping element and the second doping element in a weight ratio of 30:70 to 70:30, preferably 40:60 to 60:40, and when in the above-described range, lithium ions The effect of reducing the resistance of movement, the capacity and the effect of improving the output according to the improved durability can be more preferably implemented.

The doping element may be included in an amount of 2,500 ppm to 14,000 ppm, preferably 3,000 ppm to 9,000 ppm with respect to the total weight of the cathode active material for the lithium secondary battery.

The coating element is at least one selected from the group consisting of Al, Mg, Co, Ti, Zr and B, preferably at least one selected from the group consisting of Al, Co and B, more preferably Al and B At least one selected from the group, more preferably B, most preferably Al and B.

The coating element may include a first coating element including at least one selected from the group consisting of Mg, Co, Ti, Zr, and B and a second coating element consisting of Al. As the second coating element made of Al is used together with the first coating element as the coating element, the effect of preventing structural collapse of the active material through surface protection of the active material may be further improved. The first coating element may be at least one selected from the group consisting of Co and B, more preferably B.

The coating element may include the first coating element and the second coating element in a weight ratio of 30:70 to 70:30, preferably 40:60 to 60:40, and when in the above range, Surface protection and structural stability improvement effect can be implemented more preferably.

The coating element may be included in an amount of 1,000 ppm to 9,400 ppm, preferably 1,500 ppm to 9,000 ppm, and more preferably 1,500 ppm to 5,000 ppm, based on the total weight of the cathode active material for the lithium secondary battery.

In the cathode active material for a lithium secondary battery of the present invention, the content of the coating element and the doping element in the cathode active material is controlled at a specific ratio, indicating high structural stability and thermal stability of the active material. Therefore, it is possible to exhibit excellent capacity expression and high temperature cycle characteristics of the battery, and in particular, it can exhibit excellent structural stability and thermal stability in nickel high content lithium composite transition metal oxide or lithium high content lithium composite transition metal oxide. Capacity expression, high temperature cycle characteristics can be realized.

Anode for Lithium Secondary Battery

In addition, the present invention provides a lithium secondary battery positive electrode comprising the positive electrode active material for the lithium secondary battery.

Specifically, the positive electrode for a lithium secondary battery is formed on the positive electrode current collector and the positive electrode current collector, and includes a positive electrode active material layer containing the positive electrode active material for the lithium secondary battery.

In the positive electrode for a lithium secondary battery, the positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes to the battery, and is, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel. The surface-treated with carbon, nickel, titanium, silver, etc. can be used for the surface. In addition, the positive electrode current collector may have a thickness of about 3 to 500 μm, and may form fine irregularities on the surface of the positive electrode current collector to increase the adhesion of the positive electrode active material. For example, it can be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven body.

The cathode active material layer may include a conductive material and a binder together with the cathode active material for a lithium secondary battery described above.

The conductive material is used to impart conductivity to the electrode, and in the battery constituted, any conductive material may be used as long as it has electronic conductivity without causing chemical change. Specific examples thereof include graphite such as natural graphite and artificial graphite; Carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black and carbon fiber; Metal powder or metal fibers such as copper, nickel, aluminum, and silver; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Or conductive polymers such as polyphenylene derivatives, and the like, or a mixture of two or more kinds thereof may be used. The conductive material may typically be included in an amount of 1 to 30% by weight based on the total weight of the positive electrode active material layer.

The binder serves to improve adhesion between the positive electrode active material particles and the adhesion between the positive electrode active material and the positive electrode current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC). ), Starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubbers, or various copolymers thereof, and the like, and one or a mixture of two or more thereof may be used. The binder may be included in an amount of 1 to 30 wt% based on the total weight of the cathode active material layer.

The lithium secondary battery positive electrode may be manufactured according to a conventional positive electrode manufacturing method except for using the positive electrode active material described above. Specifically, the composition for forming a cathode active material layer including the cathode active material and optionally, a binder and a conductive material may be coated on a cathode current collector, followed by drying and rolling. In this case, the type and content of the cathode active material, the binder, and the conductive material are as described above.

The solvent may be a solvent generally used in the art, and may include dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone or acetone. Water, and the like, one of these alone or a mixture of two or more thereof may be used. The amount of the solvent is sufficient to dissolve or disperse the positive electrode active material, the conductive material, and the binder in consideration of the coating thickness of the slurry and the production yield, and to have a viscosity that can exhibit excellent thickness uniformity during application for the production of the positive electrode. Do.

In another method, the lithium secondary battery positive electrode may be manufactured by casting the composition for forming the positive electrode active material layer on a separate support, and then laminating the film obtained by peeling from the support onto a positive electrode current collector.

Lithium secondary battery

In addition, the present invention provides an electrochemical device including the positive electrode for a lithium secondary battery. The electrochemical device may be specifically a battery or a capacitor, and more specifically, may be a lithium secondary battery.

The lithium secondary battery specifically includes a positive electrode, a negative electrode positioned to face the positive electrode, a separator and an electrolyte interposed between the positive electrode and the negative electrode, and the positive electrode is the same as the positive electrode for a lithium secondary battery described above. The lithium secondary battery may further include a battery container for accommodating the electrode assembly of the positive electrode, the negative electrode, and the separator, and a sealing member for sealing the battery container.

In the lithium secondary battery, the negative electrode includes a negative electrode current collector and a negative electrode active material layer positioned on the negative electrode current collector.

The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, the negative electrode current collector may be formed on a surface of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper, or stainless steel. Surface-treated with carbon, nickel, titanium, silver, and the like, aluminum-cadmium alloy and the like can be used. In addition, the negative electrode current collector may have a thickness of about 3 to 500 μm, and like the positive electrode current collector, fine concavities and convexities may be formed on the surface of the current collector to enhance the bonding force of the negative electrode active material. For example, it can be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven body.

The negative electrode active material layer optionally includes a binder and a conductive material together with the negative electrode active material. For example, the negative electrode active material layer is coated with a negative electrode active material, and optionally a composition for forming a negative electrode including a binder and a conductive material on a negative electrode current collector and dried, or casting the negative electrode forming composition on a separate support It can also be produced by laminating a film obtained by peeling from this support onto a negative electrode current collector.

As the negative electrode active material, a compound capable of reversible intercalation and deintercalation of lithium may be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fibers, and amorphous carbon; Metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys or Al alloys; Metal oxides capable of doping and undoping lithium, such as SiO _β (0 <β <2), SnO ₂ , vanadium oxide, and lithium vanadium oxide; Or a composite including the metallic compound and the carbonaceous material, such as a Si-C composite or a Sn-C composite, and any one or a mixture of two or more thereof may be used. In addition, a metal lithium thin film may be used as the anode active material. As the carbon material, both low crystalline carbon and high crystalline carbon can be used. Soft crystalline carbon and hard carbon are typical low crystalline carbon, and high crystalline carbon is amorphous, plate, scaly, spherical or fibrous natural graphite or artificial graphite, Kish graphite (Kish) graphite, pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon microbeads, mesophase pitches and petroleum or coal tar pitch High-temperature calcined carbon such as derived cokes is typical.

In addition, the binder and the conductive material may be the same as described above in the positive electrode.

On the other hand, in the lithium secondary battery, the separator is to separate the negative electrode and the positive electrode and to provide a passage for the movement of lithium ions, if it is usually used as a separator in a lithium secondary battery can be used without particular limitation, in particular for ion transfer of the electrolyte It is desirable to have a low resistance against the electrolyte and excellent electrolytic solution-moisture capability. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer and ethylene / methacrylate copolymer, or the like Laminate structures of two or more layers may be used. In addition, conventional porous nonwoven fabrics such as nonwoven fabrics made of high melting point glass fibers, polyethylene terephthalate fibers and the like may be used. In addition, a coated separator containing a ceramic component or a polymer material may be used to secure heat resistance or mechanical strength, and may be optionally used as a single layer or a multilayer structure.

In addition, the electrolyte used in the present invention includes an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, and the like, which can be used in manufacturing a lithium secondary battery. It doesn't happen.

Specifically, the electrolyte may include an organic solvent and a lithium salt.

The organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may be an ester solvent such as methyl acetate, ethyl acetate, γ-butyrolactone or ε-caprolactone; Ether solvents such as dibutyl ether or tetrahydrofuran; Ketone solvents such as cyclohexanone; Aromatic hydrocarbon solvents such as benzene and fluorobenzene; Dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate, Carbonate solvents such as PC); Alcohol solvents such as ethyl alcohol and isopropyl alcohol; Nitriles such as R-CN (R is a C2 to C20 linear, branched or cyclic hydrocarbon group, which may include a double bond aromatic ring or an ether bond); Amides such as dimethylformamide; Dioxolanes such as 1,3-dioxolane; Or sulfolanes may be used. Of these, carbonate-based solvents are preferable, and cyclic carbonates having high ionic conductivity and high dielectric constant (for example, ethylene carbonate or propylene carbonate) that can improve the charge and discharge performance of a battery, and low viscosity linear carbonate compounds ( For example, a mixture of ethyl methyl carbonate, dimethyl carbonate or diethyl carbonate and the like is more preferable. In this case, the cyclic carbonate and the chain carbonate may be mixed and used in a volume ratio of about 1: 1 to about 1: 9, so that the performance of the electrolyte may be excellent.

The lithium salt may be used without particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the lithium salt is LiPF ₆ , LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiSbF ₆ , LiAl0 ₄ , LiAlCl ₄ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN (C ₂ F ₅ SO ₃ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ . LiCl, LiI, or LiB (C ₂ O ₄ ) ₂ and the like can be used. The concentration of the lithium salt is preferably used within the range of 0.1 to 2.0M. When the concentration of the lithium salt is included in the above range, since the electrolyte has an appropriate conductivity and viscosity, it can exhibit excellent electrolyte performance, and lithium ions can move effectively.

In addition to the electrolyte components, the electrolyte includes, for example, haloalkylene carbonate-based compounds such as difluoro ethylene carbonate, pyridine, tri, etc. for the purpose of improving battery life characteristics, reducing battery capacity, and improving discharge capacity of the battery. Ethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphate triamide, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N, N-substituted imida One or more additives such as zolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxy ethanol or aluminum trichloride may be included. In this case, the additive may be included in 0.1 to 5% by weight based on the total weight of the electrolyte.

As described above, since the lithium secondary battery including the cathode active material for a lithium secondary battery according to the present invention exhibits excellent discharge capacity, output characteristics, and capacity retention rate, portable devices such as mobile phones, laptop computers, digital cameras, and hybrids It is useful in the field of electric vehicles such as a hybrid electric vehicle (HEV).

Accordingly, the present invention provides a battery module including the lithium secondary battery as a unit cell and a battery pack including the same.

The battery module or the battery pack is a power tool (Power Tool); Electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); Or it can be used as a power source for any one or more of the system for power storage.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Example

Example 1

Transition metal hydroxide Ni _0.88 Co _0.09 Mn _0.03 (OH) ₂ prepared by mixing and co-precipitating NiSO ₄ · 6H ₂ O, CoSO ₄ · 7H ₂ O, and MnSO ₄ · H ₂ O, LiOH as a raw material containing lithium, doped ZrO ₂ and Al ₂ O ₃ were mixed as raw materials. At this time, the ratio Li / Me of the number of moles of lithium (Li) to the total number of moles of transition metals (nickel, cobalt and manganese) was adjusted to 1.07 to add a lithium-containing raw material, and Zr to the weight of the positive electrode active material for a lithium secondary battery described later. The doping raw material was added so as to be 2,000 ppm and Al 2,000 ppm.

After the mixture was first calcined at 780 ° C. for 8 hours, the primary calcined product was mixed with ultrapure water in a weight ratio of 1: 1, washed with water for 20 minutes, and filtered with a reduced pressure filter. After filtration, drying was performed under vacuum at 130 ° C. to prepare a lithium composite transition metal oxide doped with Zr and Al.

The lithium composite transition metal oxide and H ₃ BO ₃ and Al (OH) ₃ were mixed as a coating raw material. At this time, the coating raw material was added so that B 1,000ppm, Al 1,000ppm relative to the weight of the positive electrode active material for a lithium secondary battery to be described later. Thereafter, secondary baking was performed at 350 ° C. for 7 hours to prepare a cathode active material for lithium secondary battery (average particle diameter (D ₅₀ ) 15 μm) having a coating layer including B and Al formed on the lithium composite transition metal oxide.

In the positive electrode active material for a lithium secondary battery, the ratio of the doping element weight / coating element weight was 2.

Examples 2 to 11 and Comparative Examples 1 to 3

The positive electrode active material for lithium secondary batteries of Examples 2 to 11 and Comparative Examples 1 to 3 was prepared except that the doping raw material and the coating raw material were adjusted, and their kinds and dosages were adjusted.

The doping element, the content of the coating element, and the weight ratio thereof of Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 1 below.

Experimental Example

Each positive electrode active material, carbon black conductive material and PVdF binder prepared by Examples and Comparative Examples were mixed in an N-methylpyrrolidone solvent in a weight ratio of 96.5: 1.5: 2 in a positive electrode mixture ( Viscosity: 5000 mPa · s) was prepared, and applied to one surface of an aluminum current collector, dried at 130 ° C., followed by rolling to prepare a positive electrode.

The negative electrode used lithium metal.

An electrode assembly was manufactured between a cathode and an anode prepared as described above through a separator of porous polyethylene, the electrode assembly was placed in a case, and an electrolyte was injected into the case to prepare a lithium secondary battery half cell. At this time, the electrolyte is prepared by dissolving 1.0M concentration of lithium hexafluorophosphate (LiPF ₆ ) in an organic solvent consisting of ethylene carbonate / dimethyl carbonate / ethyl methyl carbonate (mixed volume ratio of EC / DMC / EMC = 3/4/3). It was.

Experimental Example 1 Evaluation of High Temperature Life Characteristics

For each lithium secondary battery half-cell prepared as described above using the respective positive electrode active materials prepared by the Examples and Comparative Examples, 0.3C, 4.25V in CCCV mode at 45 ° C. Charging (end current 1 / 20C) and discharging until a constant current of 0.3C until 2.5V was carried out to measure the capacity retention rate at the time of 30 charge and discharge experiments were carried out to evaluate the high temperature life characteristics. The results are shown in Table 2.

Referring to Table 2, it can be seen that the positive electrode active material for lithium secondary batteries of the examples prepared by the method for preparing a positive electrode active material for lithium secondary batteries of the present invention exhibited better performance than the comparative examples in capacity retention.

The ratio of doping element weight to coating element weight in the active material is in a preferred range, and in Examples 1 and 2, in which the doping elements are Zr and Ar, and the coating elements are B and Al, the capacity retention rate is greater than those of Examples 3 to 11. Was rated better.

Experimental Example 2: Evaluation of Resistance and Resistance Growth Rate

0.3C / 0.3C 30 cycles evaluated at 45 ° C for each lithium secondary battery half-cell prepared as above using the respective positive electrode active materials prepared by the Examples and Comparative Examples The discharge resistance of the cell was calculated. The resistance was calculated based on the voltage drop and the applied current value when the 4.25V fully charged cell was discharged at 0.3C for 60 seconds. Table 3 shows the calculated initial resistance value (1 cycle) and the resistance increase rate at 30 cycles.

The increase rate of resistance at 30 cycles was calculated by the following equation.

[Equation 1]

% Resistance increase at 30 cycles = (resistance at 30 cycles) / (resistance at 1 cycles) × 100

Referring to Table 3, it can be seen that the positive electrode active material for a lithium secondary battery according to the embodiments has a lower initial resistance and a lower rate of increase of resistance than the comparative examples.

In Examples 1 and 2, in which the ratio of the weight of the doping element to the weight of the coating element in the active material is a preferred range, the doping elements are Zr and Ar, and the coating elements are B and Al, the initial resistance is greater than those of Examples 3 to 11. And it can be seen that the resistance increase rate is rather low.

Experimental Example 3: Evaluation of Thermal Stability

Each lithium secondary battery half-cell manufactured using the respective positive electrode active materials prepared by the Examples and Comparative Examples was charged with a current of 0.2C and decomposed in a state of charge of 100% SOC. The anode and a new electrolyte were added to the DSC measurement cell, and thermal stability was evaluated by differential scanning calorimetry (DSC) while increasing the temperature from 400 ° C to 10 ° C per minute. As a result, the temperature at which the maximum heat peak (Main peak) appears is shown in Table 4 below. At this time, it can be evaluated that the higher the DSC peak value, the better the thermal stability.

Referring to Table 4, the positive electrode active material for a lithium secondary battery according to the embodiments has a higher maximum peak value measured by DSC than in the case of the comparative examples, and thus it can be confirmed that the structural stability and thermal stability is excellent.

However, for the comparative examples outside the ratio range of the doping element weight to the weight of the coating element in the active material of the present invention, the DSC maximum peak temperature is lower than the examples, it can be seen that the thermal stability is not good.

Experimental Example 4: Evaluation of Charge and Discharge Characteristics

For each lithium secondary battery half-cell manufactured as described above using the respective positive electrode active materials prepared by the Examples and Comparative Examples, at a room temperature (25 ° C.), at a voltage range of 2.5-4.25V. After charging and discharging under the condition of 0.2C / 0.2C, the initial charge and discharge characteristics were evaluated and the results are shown in Table 5.

Referring to Table 5, it can be confirmed that the positive electrode active material for a lithium secondary battery according to the exemplary embodiments is generally superior in charge and discharge capacity and efficiency as compared with the comparative examples.

In particular, in Comparative Examples 2 and 3, the charge and discharge capacity and efficiency are much lower than those in the Examples. In the case of Comparative Example 1, the charge and discharge capacity and the efficiency are similar to those of the Examples, but as described above, Comparative Example 1 has a much lower performance than the Examples in terms of capacity retention, resistance characteristics, and thermal stability. You can see this is not good.

Claims (17)

1. Transition metal hydroxides including transition metals including nickel (Ni), cobalt (Co) and manganese (Mn), raw materials containing lithium and at least selected from the group consisting of Al, Mg, Co, V, Ti, Zr and W Preparing a lithium composite transition metal oxide doped with the doping element by mixing and firstly baking a doping raw material including one doping element; And

   The lithium composite transition metal oxide and the coating raw material including at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr, and B are mixed and subjected to a second firing treatment to form the lithium composite transition metal oxide phase. Manufacturing a cathode active material for a lithium secondary battery in which a coating layer including the coating element is formed;

   The doping raw material and the coating raw material is added to the ratio of the weight of the doping element to the weight of the coating element in the positive electrode active material for lithium secondary batteries, the manufacturing method of a lithium secondary battery positive electrode active material.
2. The method according to claim 1, wherein the doping raw material is added so that the content of the doping element is 2,500ppm to 14,000ppm with respect to the total weight of the positive electrode active material for lithium secondary batteries.
3. The method according to claim 1, wherein the coating raw material is added so that the content of the coating element is 1,000 ppm to 9,400 ppm with respect to the total weight of the positive electrode active material for lithium secondary batteries.
4. The method of claim 1, wherein the doping raw material comprises at least one first doping element selected from the group consisting of Co and Zr and at least one second doping element selected from the group consisting of Al, Mg, V and W. , Manufacturing method of positive electrode active material for lithium secondary battery.
5. The method of claim 4, wherein the doping raw material comprises the first doping element and the second doping element in a weight ratio of 30:70 to 70:30.
6. The method of claim 1, wherein the doping raw material comprises at least one doping element selected from the group consisting of Zr, Co, and Al.
7. The method of claim 1, wherein the coating raw material comprises at least one first coating element selected from the group consisting of Mg, Ti, Zr, and B and a second coating element consisting of Al. .
8. The method of claim 7, wherein the coating raw material comprises the first coating element and the second coating element in a weight ratio of 30:70 to 70:30.
9. The method of claim 1, wherein the coating raw material comprises at least one coating element selected from the group consisting of Al, Co, and B.
10. The method of claim 1, wherein the transition metal hydroxide has a content of nickel (Ni) of 70 mol% or more in all transition metal elements contained in the transition metal hydroxide.
11. At least one doping element selected from the group consisting of transition metals including nickel (Ni), cobalt (Co) and manganese (Mn) and Al, Mg, Co, V, Ti, Zr and W doped therein Lithium composite transition metal oxide; And

    And a coating layer formed on the lithium composite transition metal oxide and including at least one coating element selected from the group consisting of Al, Mg, Co, Ti, Zr, and B.

    The ratio of the weight of the doping element to the weight of the coating element is 0.3 to 7, positive electrode active material for a lithium secondary battery.
12. The cathode active material of claim 11, wherein the doping element is included in an amount of 2,500 ppm to 14,000 ppm with respect to the total weight of the cathode active material for the lithium secondary battery.
13. The cathode active material of claim 11, wherein the coating element is included in an amount of 1,000 ppm to 9,400 ppm with respect to the total weight of the cathode active material for lithium secondary battery.
14. The method according to claim 11, wherein the doping element comprises at least one first doping element selected from the group consisting of Co and Zr and at least one second doping element selected from the group consisting of Al, Mg, V and W, Cathode active material for lithium secondary battery.
15. The positive active material of claim 11, wherein the coating element comprises at least one first coating element selected from the group consisting of Mg, Ti, Zr, and B and a second coating element consisting of Al.
16. The positive electrode for lithium secondary batteries containing the positive electrode active material for lithium secondary batteries of Claim 11.
17. Lithium secondary battery containing the positive electrode for lithium secondary batteries of Claim 16.