WO2018143734A1 - Cathode active material for secondary battery, and preparation method therefor - Google Patents

Abstract

The present invention relates to a cathode active material for a secondary battery, and a preparation method therefor, the cathode active material comprising: a core comprising a lithium composite metal oxide; and a surface treatment layer positioned on the core and comprising an amorphous oxide, which comprises lithium (Li), boron (B), and aluminum (Al), wherein the amount of lithium by-products present on the surface is less than 0.55 wt% on the basis of the total weight.

Description

Anode Active Material for Secondary Battery and Manufacturing Method Thereof

Citation with Related Applications

This application claims the benefit of priority based on Korean Patent Application No. 2017-0015158 dated February 2, 2017 and Korean Patent Application No. 2018-0013454 dated February 2, 2018. The contents are included as part of this specification.

Field of technology

The present invention relates to a cathode active material for a secondary battery and a method of manufacturing the same, in which resistance is reduced and gas generation in the secondary battery is reduced.

As technology development and demand for mobile devices increase, the demand for secondary batteries as a source of energy is rapidly increasing. Among such secondary batteries, lithium secondary batteries having high energy density and voltage, long cycle life, and low self discharge rate have been commercialized and widely used.

However, a lithium secondary battery has a problem in that its life is rapidly decreased as charging and discharging are repeated. In particular, this problem is more serious in long life or high voltage cells. This is due to a phenomenon in which the electrolyte is decomposed or the active material is deteriorated due to moisture or other effects inside the battery, and the internal resistance of the battery is increased. In particular, in the case of the cathode material, when the cathode material itself deteriorates, the dissolution of the cathode active material constituents increases, and as a result, the battery life is rapidly deteriorated or cannot be used at high voltage.

In order to solve this problem, methods for forming a surface treatment layer on the surface of the positive electrode active material have been proposed. In the case of the aluminum-based surface treatment layer, which is recognized for its stability in the high voltage and the electrolyte, it is difficult to uniformly coat the entire active material because it is coated on the particle surface in a crystalline state. In addition, there is a problem of increased resistance due to the crystallinity of the aluminum compound itself. In addition, in the case of the boron (B) -based coating is uniformly coated in an amorphous state does not interfere with the movement of lithium ions moving from the cathode material to the electrolyte. However, since the boron (B) -based coating reacts with moisture, there is a problem in that the reaction with the electrolyte prolongs the role of the coating layer.

Accordingly, there is an urgent need to develop a cathode active material capable of improving the performance of a lithium secondary battery while solving the above problems.

An object of the present invention is to provide a positive electrode active material and a method of manufacturing the same, which has excellent resistance to output due to reduced resistance and reduced gas generation in a secondary battery.

In order to solve the above problems, the present invention is a core containing a lithium composite metal oxide; And a surface treatment layer disposed on the core and including an amorphous oxide including lithium (Li), boron (B), and aluminum (Al), wherein the surface treatment layer includes lithium oxide, boron oxide, and aluminum oxide. Amorphous oxides chemically bonded to each other, the amorphous oxide in the surface treatment layer, the content of aluminum oxide is more than the content of boron oxide, the lithium by-product content present on the surface is less than 0.55% by weight relative to the total weight It provides a cathode active material for a secondary battery.

In addition, the present invention comprises a first step of preparing a mixture by mixing a lithium composite metal oxide, a boron-containing raw material and an aluminum-containing raw material; And a second step of forming the surface treatment layer including an amorphous oxide on a core including the lithium composite metal oxide by heat treating the mixture under an oxygen atmosphere. The forming of the amorphous oxide includes: Lithium by-products present on the surface of the oxide and the boron-containing raw material and aluminum-containing raw material react to form an amorphous oxide containing lithium, boron and aluminum, and contain the aluminum more than the content of the boron-containing raw material. The content of the raw material is more than 1 times less than 2.5 times more, and the heat treatment is to be carried out at 500 ℃ to 800 ℃, to provide a method for producing a cathode active material for secondary batteries.

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

The cathode active material of the present invention has excellent lithium ion conductivity even when a surface treatment layer including an amorphous oxide is positioned on a core including a lithium composite metal oxide, and thus may have excellent output characteristics due to a low resistance increase rate even though the number of charge / discharge increases. have.

In the cathode active material of the present invention, a surface treatment layer containing an amorphous oxide on a core including a lithium composite metal oxide prevents direct contact between the core and the lithium composite metal oxide, thereby preventing a lithium composite metal from an electrolyte and an electrolyte-derived hydrogen fluoride. Damage to the oxide can be prevented. It is also possible to prevent the gas generated from the contact.

The positive electrode active material of the present invention can reduce the amount of lithium by-products in the positive electrode active material because LiOH and Li ₂ CO ₃ present on the surface of the positive electrode active material are removed by reaction with boron and / or aluminum-containing materials when forming the surface treatment layer. .

1 is a graph showing the discharge capacity retention rate compared to the initial cycle of the lithium secondary battery prepared in Examples 1 to 2, Comparative Examples 1 to 7.

2 is a graph showing a DC resistance increase rate according to the number of cycles compared to the DC resistance of the initial cycle of the lithium secondary batteries manufactured in Examples 1 to 2 and Comparative Examples 1 to 7.

3 is a graph measuring the amount of increase in gas generation over time compared to the initial amount of gas generation of the lithium secondary batteries manufactured in Examples 1 to 2 and Comparative Examples 1 to 3 and 6.

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

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 cathode active material for a secondary battery according to an embodiment of the present invention may include a core including a lithium composite metal oxide.

The lithium composite metal oxide is a compound (lithiated intercalation compound) capable of reversible intercalation and deintercalation of lithium. For example, the lithium composite metal compound may be a layered lithium composite metal oxide that can be used at high capacity and high voltage.

The lithium composite metal compound may be represented by the following Chemical Formula 1.

<Formula 1>

Li _a (Ni _x Co _y M1 _z ) _b M2 _c O ₂

In Formula 1, M1 is at least one element selected from the group consisting of Mn and Al, M2 is at least one element selected from the group consisting of Ba, Ca, Zr, Ti, Mg, Ta, Nb and Mo , 1 ≦ a ≦ 1.5, 0.9 ≦ b ≦ 1, 0 ≦ c ≦ 0.1, 0.6 ≦ x <1, 0 <y <0.4, 0 <z ≦ 0.4, and b + c = 1.

In the lithium composite metal oxide represented by Chemical Formula 1, Li may be included in an amount corresponding to a, that is, 1 ≦ a ≦ 1.5, specifically 1 ≦ a ≦ 1.2. When the above-mentioned range is satisfied, the effect of improving the capacity characteristics of the cathode active material according to the Li content control is remarkable, and the sinterability at the time of manufacturing the active material can be balanced. If a is less than 1, the capacity may be lowered. If a is more than 1.5, the particles may be sintered in the firing process, and thus production of the active material may be difficult.

In the lithium composite metal oxide represented by Chemical Formula 1, Ni may be included in an amount corresponding to x, that is, 0.6 ≦ x <1, specifically, 0.7 ≦ x <0.95. When the content of Ni satisfies the above range, it is possible to implement a high capacity cathode active material.

In the lithium composite metal oxide represented by Chemical Formula 1, Co is included in a content corresponding to y, that is, 0 <y <0.4, specifically 0 <y≤0.2, more specifically 0.04 <y≤0.15. Can be. When the above range is satisfied, the capacity characteristic can be improved. If y is 0, there is a fear that the capacity characteristics are lowered. If the above range is exceeded, there is a fear of increased cost.

In addition, in the lithium composite metal oxide of Chemical Formula 1, M1 may be at least one selected from the group consisting of Mn and Al. In the case of Mn, which is M1, since the capacity characteristics and structural stability of the cathode active material are improved, the secondary battery, which is a final product, may realize high capacity, and output characteristics may be improved. When M1 is Al, output characteristics of the active material may be improved.

M1 may be included in an amount corresponding to z, 0 <z ≦ 0.4, specifically 0 <z ≦ 0.2, and more specifically 0.02 <z ≦ 0.15. If z is 0, the improvement effect of the inclusion of M1 cannot be obtained. If it exceeds the above-mentioned range, there is a fear that the output characteristics and capacity characteristics of the secondary battery rather deteriorate.

In addition, in the lithium composite metal oxide of Formula 1, M2 may be included in an amount corresponding to c, that is, 0≤c≤0.1, preferably 0≤c≤0.05. When the above range is satisfied, the structural stability of the cathode active material may be improved, and as a result, the output characteristics of the secondary battery may be improved. Specifically, M2 may be at least one element selected from the group consisting of Ba, Ca, Zr, Ti, Mg, Ta, Nb, and Mo, and preferably, one kind selected from the group consisting of Zr, Ti, and Mg. It may be abnormal.

Meanwhile, a is a molar ratio of Li in the lithium composite metal oxide, b is a molar ratio of Ni, Co, and M1 in the lithium composite metal oxide, and c is a molar ratio of M2 in the lithium composite metal oxide. In this case, b + c may be 1.

The lithium composite metal oxide may be primary particles or secondary particles in which primary particles are aggregated. In this case, the primary particles may be uniform or nonuniform. In addition, the lithium composite metal oxide may further include having a segregated phase of the Zr oxide at the surface of the secondary particles or grain boundaries between the primary particles.

In addition, the cathode active material may have an average particle diameter (D ₅₀ ) of 1 ㎛ to 20 ㎛. If the average particle diameter of the positive electrode active material is less than 1 μm, there is a fear of dispersibility in the positive electrode mixture due to aggregation between the positive electrode active materials. If the average particle diameter exceeds 20 μm, the mechanical strength and the specific surface area of the positive electrode active material may be reduced. In addition, considering the remarkable effect of improving the rate characteristics and initial capacity characteristics of the battery according to the positive electrode active material particle size control may have an average particle diameter (D ₅₀ ) of 3㎛ 18㎛. In addition, when the cathode active material is secondary particles, the average particle diameter (D ₅₀ ) of the primary particles constituting the cathode active material may be 50 nm to 1,000 nm.

In the present invention, the average particle diameter (D ₅₀ ) of the positive electrode active material may be defined as the particle diameter at 50% of the particle diameter distribution. In the present invention, the average particle diameter (D ₅₀ ) of the positive electrode active material can be measured using, for example, a laser diffraction method. Specifically, the average particle diameter (D ₅₀ ) of the positive electrode active material is dispersed in the positive electrode active material in the dispersion medium, and then introduced into a commercially available laser diffraction particle size measuring device (for example, Microtrac MT 3000) to output ultrasonic waves of about 28 kHz irradiated with 60 W, and it is possible to calculate the mean particle size (D ₅₀₎ of from 50% based on the particle size distribution of the measuring device.

The cathode active material according to an embodiment of the present invention may include a surface treatment layer disposed on the core and including an amorphous oxide including lithium (Li), boron (B), and aluminum (Al).

Since the amorphous oxide is located on the core without reacting with the electrolyte and the hydrogen fluoride derived from the electrolyte, it is possible to prevent or minimize the direct contact between the core and the electrolyte and the hydrogen fluoride derived from the electrolyte. Accordingly, damage to the core due to the electrolyte solution and the hydrogen fluoride derived from the electrolyte solution can be minimized, and thus the life characteristics of the lithium secondary battery that is the final product can be improved.

In addition, the positive electrode active material may be less than 0.55% by weight, preferably 0.4% to 0.55% by weight based on the total weight of lithium by-products present on the surface. As described above, when a lithium composite metal compound having a nickel content of 60 mol% or more with respect to the total number of moles of the lithium composite metal compound is used as a core, an excessive amount of lithium byproduct may be generated on the surface of the positive electrode active material while exhibiting high capacity characteristics. There is a disadvantage. Thus, when forming a surface treatment layer containing an amorphous oxide on the core, the amorphous oxide is a lithium by-products such as LiOH and Li ₂ CO ₃ present on the surface of the core reacts with the boron and / or aluminum-containing material Since it is formed of amorphous oxide, it is possible to reduce the amount of lithium by-products in the positive electrode active material. For example, when the amount of lithium by-products present on the surface of the positive electrode active material exceeds the above range, the reaction between the lithium salts contained in the electrolyte and the lithium by-products continues to occur, resulting in oxygen, HF, H ₂ O and other gases. Generation of the lithium secondary battery may adversely affect the performance of the lithium secondary battery. Specifically, the reaction may be represented by the following Scheme 1.

<Scheme 1>

LiPF ₆ → LiF + PF ₅

PF ₅ + 2LiOH → 2LiF + H ₂ O + POF ₃

PF ₅ + H ₂ O → POF ₃ + 2HF

4PF ₅ + 2Li ₂ CO ₃ → 3LiPF ₆ + 2CO ₂ + LiPO ₂ F ₂

2HF + Li ₂ CO ₃ → 2LiF + H ₂ O + CO ₂

Specifically, the surface treatment layer may include lithium oxide, boron oxide, and aluminum oxide, and the amorphous oxide in the surface treatment layer may include more aluminum oxide than boron oxide. For example, the surface treatment layer may include an amorphous oxide containing Li ₂ O, B ₂ O ₃ and Al ₂ O _3, said Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ are each chemical Can be combined. Preferably, the amorphous oxide may be present in a chemical bond in the form of Li ₂ OB ₂ O ₃ -Al ₂ O ₃ . For example, the amorphous oxide is _{2LiAl 7 B 4 O 5, 2LiAlB} 2 O 5 , or 2Li ₂ AlB ₂ O may be present in the form of _5, wherein the amorphous oxide is B and the 1 Al: 1 in excess and less than 2.5, preferably Preferably it may be included in a molar ratio of greater than 1: 1 to less than 2. As in the present invention, when the amorphous oxides include B and Al in the above ranges and are chemically bonded to each other, the reduction effect of lithium by-products present on the surface is large, thereby improving gas generation by reaction with the electrolyte solution. Can be.

For example, the amorphous oxide included in the surface treatment layer is present in the form of a mixture of one of Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ , or two of them are chemically bonded to each other and the other one alone When present as, specifically, Al ₂ O ₃ , Li ₂ O-Al ₂ O ₃ , Li ₂ OB ₂ O ₃ , Li ₂ 0-B ₄ O ₅ When present in, for example, the effect of reducing the lithium by-products present on the surface is small, it can generate a large amount of gas when reacting with the electrolyte.

The Li ₂ O can lower the high temperature viscosity of the amorphous oxide to improve meltability and formability. Li ₂ O is excellent in lithium ion conductivity and does not react with the electrolyte solution and the hydrogen fluoride derived from the electrolyte solution during charging / discharging. Accordingly, the core can be effectively protected to improve life and cycle characteristics of the positive electrode active material. The Li ₂ O may be derived from LiOH and Li ₂ CO ₃ which are lithium by-products present on the surface of the core.

The B ₂ O ₃ is a main component constituting the glass composition, forms a three-dimensional network in the glass and serves to increase the thermal chemical stability. However, since the B ₂ O ₃ reacts with water, it may reduce the chemical stability of the surface treatment layer when included in a large amount in the amorphous oxide.

Al ₂ O ₃ is a material having high lithium ion conductivity and may function as a network forming agent in an amorphous oxide. The Al ₂ O ₃ may affect the thermal expansion coefficient and the high temperature viscosity of the amorphous oxide.

When the surface treatment layer including the amorphous oxide is formed on the core, the reaction between the electrolyte and the hydrogen fluoride derived from the electrolyte during charging and discharging may be suppressed due to the excellent lithium ion conductivity, thereby improving life characteristics. In addition, it is possible to provide a cathode active material having improved thermal stability.

In addition, the surface treatment layer containing the amorphous oxide as described above may be uniformly formed on the entire surface of the core.

The surface treatment layer is preferably formed uniformly in an appropriate thickness in consideration of the particle diameter of the core to determine the capacity of the positive electrode active material. Specifically, the surface treatment layer may have an average thickness of 20 nm to 100 nm, preferably 50 nm to 100 nm, with respect to a semi-diameter of the core. If it is less than the above-mentioned range, the improvement effect of forming the surface treatment layer may be insignificant, and if it exceeds the above-mentioned range, the resistance of the positive electrode active material may increase.

In the present invention, the particle diameter of the core and the thickness of the surface treatment layer may be measured through particle cross-sectional analysis using a focused ion beam (fib).

On the other hand, the method for producing a positive electrode active material according to another embodiment of the present invention comprises a first step of preparing a mixture by mixing a lithium composite metal oxide, boron-containing raw material and aluminum-containing raw material; And heat treating the mixture under an oxygen atmosphere to form a surface treatment layer including an amorphous oxide on the core including the lithium composite metal oxide, wherein forming the amorphous oxide comprises forming the lithium composite metal oxide. Lithium by-products present on the surface of the boron-containing raw material and aluminum-containing raw material react to form an amorphous oxide containing lithium, boron, and aluminum, and the aluminum-containing raw material rather than the content of the boron-containing raw material. The content of the material is more than 1 times and less than 2.5 times more, the heat treatment is to be carried out at 500 ℃ to 800 ℃.

The lithium composite metal oxide may be any compound capable of reversible intercalation and deintercalation of lithium used in the art (lithiated intercalation compound), and the kind thereof is not particularly limited. For example, the lithium composite metal oxide may be represented by Chemical Formula 1. In addition, the lithium composite metal oxide may be prepared through a general method used in the art, or a commercially available lithium composite metal oxide may be purchased and used.

On the other hand, with respect to the total number of moles of the lithium composite metal oxide, when the nickel content is more than 60 mol%, the positive electrode active material exhibits high capacity characteristics, while the excessive amount of lithium by-products on the surface due to the low reactivity of the lithium source and the precursor during firing Could be generated as As described above, when an excessive amount of lithium byproducts is present on the surface of the lithium composite metal oxide, lithium salts included in the electrolyte react with the lithium byproducts, thereby generating gas, which may adversely affect the performance of the secondary battery. have.

Accordingly, by mixing and heat treating the lithium composite metal oxide, the boron-containing raw material and the aluminum-containing raw material, the lithium by-product present on the surface of the lithium composite metal oxide, the boron-containing raw material and the aluminum-containing raw material react. Accordingly, it was found that not only the content of lithium by-products present on the surface of the lithium composite metal oxide can be reduced, but also a cathode active material having excellent output characteristics can be prepared according to the formation of an amorphous oxide having excellent lithium ion conductivity. The present invention has been completed.

The boron-containing raw material may be at least one selected from the group consisting of H ₃ BO ₃ , HBPO ₄ , B ₂ O ₃ , B ₂ O ₅ , Li ₂ B ₄ O ₇ and (NH ₄ ) ₂ B ₄ O ₇ . And specifically, H ₃ BO ₃ .

The aluminum-containing raw material may be at least one selected from the group consisting of Al (OH) ₃ , Al ₂ (SO ₄ ) ₃ , AlCl ₃ and Al (NO ₃ ) ₃ , specifically, Al (OH) ₃ days Can be.

In the first step, based on 100 parts by weight of the lithium composite metal oxide, 0.1 to 0.8 parts by weight, preferably 0.1 to 0.5 parts by weight, more preferably 0.1 to 0.2 parts by weight of the boron-containing raw material and the aluminum The containing raw material may be mixed in an amount of 0.1 to 1 parts by weight, preferably 0.1 to 0.5 parts by weight, more preferably 0.3 to 0.5 parts by weight. At this time, the content of the aluminum-containing raw material than the boron-containing raw material may include more than 1 times less than 2.5 times, preferably 1.1 times to 2 times more.

As described above, when the content of the aluminum-containing raw material is higher than the boron-containing raw material, Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ may be present in a chemical bond with each other. On the other hand, the content of the boron-containing raw material than the content of the aluminum-containing raw material in the range of the content of the aluminum-containing raw material and the content of the boron-containing raw material is the same, or the content of the aluminum-containing raw material is more than the above range. When the content is high, the amorphous oxide may be present in the form of a mixture of one of Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ , or two of them may be chemically bonded to each other and the other one may be present alone.

In addition, when mixing in the first step, the content of the aluminum-containing raw material than the boron-containing raw material may include more than 1 times less than 2.5 times, preferably 1.1 times to 2 times more.

As described above, when the content of the aluminum-containing raw material is higher than that of the boron-containing raw material, the formation of lithium boron aluminum oxide in which Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ chemically bond with each other is advantageous. , Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ is unlikely to exist alone in the surface treatment layer, respectively, is effective in reducing lithium by-products, and the output and resistance characteristics may be improved. On the other hand, the content of the boron-containing raw material than the content of the aluminum-containing raw material in the range of the content of the aluminum-containing raw material and the content of the boron-containing raw material is the same, or the content of the aluminum-containing raw material is more than the above range. When the content is large, Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ in the surface treatment layer are each present alone, the effect of reducing lithium by-products is insignificant and gas may be generated. In addition, when Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ are present alone in the surface treatment layer, the surface treatment layer acts as a resistance layer, which may cause an increase in resistance.

On the other hand, it is preferable that the said mixing is solid mixing. This is because, when the solid phase mixing method is used, there is no fear of formation of a side reaction product by a solvent or the like used in the liquid phase mixing, and a more uniform surface treatment layer can be formed.

The average particle diameter of the boron-containing raw material may be more than 5㎛, 50㎛ or less, so as to be suitable for solid phase mixing. The average particle diameter of the aluminum-containing raw material may be more than 0 to 1 ㎛ or less, suitable for solid phase mixing. When the above range is satisfied, the core is uniformly coated, and raw materials can be prevented from agglomerating.

Since the aluminum-containing raw material is less reactive than the boron-containing raw material, the average particle diameter is preferably smaller than the boron-containing raw material.

The boron and aluminum raw materials may be subjected to a separate grinding process to have the above average particle diameter. The grinding may be a conventional grinding process such as a ball mill.

Next, the heat treatment in the second step may be performed at 500 ℃ to 800 ℃, specifically 500 ℃ to 700 ℃. When the above-mentioned temperature is satisfied, Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ in the amorphous oxide may be present in a chemical bond with each other. If it is below the above-mentioned temperature, one of Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ is present in the form of a mixture in the amorphous oxide, or two of them are physically or chemically bonded to each other and the other one alone exist. Specifically, Al ₂ O ₃ , Li ₂ O-Al ₂ O ₃ , Li ₂ OB ₂ O ₃ , Li ₂ 0-B ₄ O ₅ And the like in the form of a mixture in the amorphous oxide, the effect of the surface treatment layer of the present invention can not be realized. Exceeding the above temperature may cause denaturation of the positive electrode active material.

The heat treatment process may be performed for 3 hours to 40 hours, specifically 5 hours to 10 hours under the above conditions.

In addition, the heat treatment process may be carried out in a multi-step within the above temperature range, in this case it may be performed by varying the temperature in accordance with the progress of each step.

In addition, according to another embodiment of the present invention can provide a positive electrode including the positive electrode active material.

Specifically, the positive electrode is formed on the positive electrode current collector and the positive electrode current collector, and comprises a positive electrode active material layer containing a positive electrode active material according to the present invention.

The positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, carbon, nickel, titanium on the surface of stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel Surface treated with silver, silver or the like can be used. 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 current collector to increase 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.

In addition, the cathode active material layer may include a conductive material and a binder together with the cathode active material described above.

In this case, the conductive material is used to impart conductivity to the electrode. In the battery constituted, the conductive material may be used without particular limitation 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.

In addition, the binder serves to improve adhesion between the cathode active material particles and adhesion between the cathode active material and the 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% by weight based on the total weight of the positive electrode active material layer.

The positive electrode may be manufactured according to a conventional positive electrode manufacturing method except for using the positive electrode active material. For example, the above positive electrode active material and optionally, a binder and a conductive material are dissolved or dispersed in a solvent to form a slurry for forming a positive electrode active material layer, and the slurry is coated on a positive electrode current collector, followed by drying and rolling. Can be. 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, for example, dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone ( acetone) or water, but is not limited thereto. The said solvent may be used individually by 1 type of solvent, and may mix and use 2 or more types of solvent. 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.

Alternatively, the positive electrode may be prepared by casting the slurry 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.

According to another embodiment of the present invention, an electrochemical device including the anode is provided. The electrochemical device may be specifically a battery, a capacitor, or the like, and more specifically, 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 as 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. The negative electrode active material layer is, for example, by dissolving or dispersing a negative electrode active material, and optionally a binder and a conductive material in a solvent to form a slurry for forming a negative electrode, and applying the slurry onto a negative electrode current collector and drying, or for forming the negative electrode The slurry may be cast on a separate support, and then the film obtained by peeling from the support is laminated on 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 _x (0 <x <2), SnO ₂ , vanadium oxide, 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, the conductive material and the solvent 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 in the 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 including 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, examples of the electrolyte used in the present invention include 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; Dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (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 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 according to the present invention stably exhibits excellent discharge capacity, output characteristics, and capacity retention rate, portable devices such as mobile phones, notebook computers, digital cameras, and hybrid electric vehicles ( It is useful for electric vehicle fields such as hybrid electric vehicle (HEV).

Accordingly, according to another embodiment of the present invention, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided.

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 1

(Manufacture of Anode Active Material)

The lithium composite metal oxide _{(Li (Ni 0.83 Co 0.11 Mn} 0.06) 0. 97 Zr 0. 03 O 2) in an amount as described in, the following Table 1 based on 100 parts by weight of H ₃ BO _3, and Al (OH) ₃ After mixing with a dry mixer (CYCLOMIX, HOSOKAWA Micron Coorporation) and heat treatment for 5 hours at the temperature shown in Table 1 under an oxygen atmosphere to prepare a cathode active material having a surface treatment layer comprising an amorphous oxide shown in Table 1.

(Manufacture of Anode)

The cathode active material, carbon black as a conductive material, and PVDF as a binder were mixed in a weight ratio of 95: 2.5: 2.5 in a solvent of N-methylpyrrolidone to prepare a composition for forming a cathode (viscosity: 5,000 mPa · s). . The composition for forming a positive electrode was applied to an aluminum current collector, dried at 130 ° C., and then rolled to prepare a positive electrode.

(Production of a cathode)

As a negative electrode active material, a natural graphite, a carbon black conductive material, and a polyvinylidene fluoride (PVDF) binder were mixed in a weight ratio of 85: 10: 5 in a solvent of N-methylpyrrolidone to prepare a composition for forming a negative electrode, and the copper It was applied to the current collector to prepare a negative electrode.

(Manufacture of Lithium Secondary Battery)

An electrode assembly was manufactured by interposing a porous polyethylene as a separator between the positive electrode and the negative electrode, and the electrode assembly was placed in a case, and an electrolyte solution was injected into the case to prepare a lithium secondary battery. 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 (mixing volume ratio of EC / EMC / DEC = 3/4/3). It was.

Example 2

The lithium composite metal oxide _{(Li (Ni 0.83 Co 0.11 Mn} 0.06) 0. 97 Zr 0. 03 O 2) in an amount as described in, the following Table 1 based on 100 parts by weight of H ₃ BO _3, and Al (OH) ₃ to a dry mixer After mixing, heat treatment at 500 ℃ to prepare a cathode active material having a surface treatment layer comprising an amorphous oxide of the composition shown in Table 1. Except for using this, a positive electrode and a lithium secondary battery was prepared in the same manner as in Example 1.

Comparative example  One

Except for using a lithium composite metal oxide (Li (Ni _0.83 Co _0.11 Mn _0.06 ) _0.97 Zr _0.03 O ₂ ) without a surface treatment layer as a positive electrode active material, the positive electrode and the lithium secondary in the same manner as in Example 1 The battery was prepared.

Comparative example  2

The lithium composite metal oxide _{(Li (Ni 0.83 Co 0.11 Mn} 0.06) 0. 97 Zr 0. 03 O 2) After a mixture of H ₃ BO ₃ in an amount as described in, the following Table 1 based on 100 parts by weight of a dry mixer, 300 Heat treatment at 占 폚 produced a cathode active material having a surface treatment layer including an amorphous oxide having the composition shown in Table 1. Except for using this, a positive electrode and a lithium secondary battery was prepared in the same manner as in Example 1.

Comparative example  3

The lithium composite metal oxide _{(Li (Ni 0.83 Co 0.11 Mn} 0.06) 0. 97 Zr 0. 03 O 2) After a mixture of Al (OH) ₃ in an amount as described in, the following Table 1 based on 100 parts by weight of a dry mixer, Heat treatment at 300 ℃ to prepare a cathode active material having a surface treatment layer comprising an amorphous oxide of the composition shown in Table 1. Except for using this, a positive electrode and a lithium secondary battery was prepared in the same manner as in Example 1.

Comparative example  4

The lithium composite metal oxide _{(Li (Ni 0.83 Co 0.11 Mn} 0.06) 0. 97 Zr 0. 03 O 2) in an amount as described in, the following Table 1 based on 100 parts by weight of H ₃ BO _3, and Al (OH) ₃ to a dry mixer After mixing, heat treatment at 700 ℃ to prepare a cathode active material having a surface treatment layer comprising an amorphous oxide of the composition shown in Table 1. Except for using this, a positive electrode and a lithium secondary battery was prepared in the same manner as in Example 1.

Comparative example  5

The lithium composite metal oxide _{(Li (Ni 0.83 Co 0.11 Mn} 0.06) 0. 97 Zr 0. 03 O 2) in an amount as described in, the following Table 1 based on 100 parts by weight of H ₃ BO _3, and Al (OH) ₃ to a dry mixer After mixing, heat treatment at 700 ℃ to prepare a cathode active material having a surface treatment layer comprising an amorphous oxide of the composition shown in Table 1. Except for using this, a positive electrode and a lithium secondary battery was prepared in the same manner as in Example 1.

Comparative example  6

The lithium composite metal oxide _{(Li (Ni 0.83 Co 0.11 Mn} 0.06) 0. 97 Zr 0. 03 O 2) in an amount as described in, the following Table 1 based on 100 parts by weight of H ₃ BO _3, and Al (OH) ₃ to a dry mixer After mixing, heat treatment at 300 ℃ to prepare a cathode active material having a surface treatment layer comprising an amorphous oxide of the composition shown in Table 1. Except for using this, a positive electrode and a lithium secondary battery was prepared in the same manner as in Example 1.

Comparative example  7

The lithium composite metal oxide _{(Li (Ni 0.83 Co 0.11 Mn} 0.06) 0. 97 Zr 0. 03 O 2) in an amount as described in, the following Table 1 based on 100 parts by weight of H ₃ BO _3, and Al (OH) ₃ to a dry mixer After mixing, heat treatment at 700 ℃ to prepare a cathode active material having a surface treatment layer comprising an amorphous oxide of the composition shown in Table 1. Except for using this, a positive electrode and a lithium secondary battery was prepared in the same manner as in Example 1.

division	H 3 BO 3 (parts by weight)	Al (OH) 3 (parts by weight)	Heat treatment temperature (℃)	Amorphous oxide
				Furtherance	Average thickness (nm)
Example 1	0.2	0.3	700	Li 2 OB 2 O 3 -Al 2 O 3	70
Example 2	0.2	0.3	500	Li 2 OB 2 O 3 -Al 2 O 3	70
Comparative Example 1	0	0	0	-	-
Comparative Example 2	0.2	0	300	Li 2 OB 2 O 3	70
Comparative Example 3	0	0.3	300	Li 2 O-Al 2 O 3	70
Comparative Example 4	0.2	0.2	700	Li 2 OB 2 O 3 -Al 2 O 3	70
Comparative Example 5	0.3	0.2	700	Li 2 OB 2 O 3 -Al 2 O 3	70
Comparative Example 6	0.2	0.3	300	Li 2 OB 2 O 3 -Al 2 O 3	70
Comparative Example 7	0.2	0.5	700	Li 2 OB 2 O 3 -Al 2 O 3	70

Experimental Example  One: Of positive electrode active material  Property evaluation

The amount of lithium by-products remaining on the surfaces of the cathode active materials prepared in Examples 1 to 2 and Comparative Examples 1 to 7 was measured using a pH titration method. In the measuring method, 10 g of positive electrode active material was poured into distilled water to dissolve lithium by-products remaining on the surface of the positive electrode active material, and then the solution was filtered and 0.1M HCl was injected at a rate of 0.3-0.5 mL / min. At this time, the residual lithium byproduct content was calculated from the amount of HCl injected up to pH 5. The instrument used for pH titration is Metrohm's instrument. The results are shown in Table 2 below. In the following Table 2, the content of LiOH and Li ₂ CO ₃ is described in weight percent based on the total weight of the positive electrode active material.

division	LiOH (% by weight)	Li 2 CO 3 (% by weight)	Total (% by weight)
Example 1	0.424	0.057	0.481
Example 2	0.428	0.115	0.543
Comparative Example 1	0.480	0.730	1.210
Comparative Example 2	0.422	0.135	0.557
Comparative Example 3	0.465	0.564	1.029
Comparative Example 4	0.433	0.125	0.558
Comparative Example 5	0.438	0.127	0.565
Comparative Example 6	0.452	0.157	0.609
Comparative Example 7	0.44	0.131	0.571

Referring to Table 2, in the case of the cathode active materials prepared in Examples 1 to 2, the lithium by-product content was less than 0.55% by weight based on the total weight of the cathode active material, compared to the cathode active materials prepared in Comparative Examples 1-7. It was confirmed that the amount of by-products is small.

Experimental Example 2: Characterization of the lithium secondary battery (1)

The lithium secondary batteries prepared in Examples 1 to 2 and Comparative Examples 1 to 7 were charged / discharged 30 times at a temperature of 0.3 C / 0.3 C at 45 ° C. within a 2.5 V to 4.25 V driving voltage range. The discharge capacity retention ratio, which is the ratio of the discharge capacity according to the number of cycles to the discharge capacity of one cycle, was measured. The results are shown in FIG.

Referring to FIG. 1, the change in capacity retention ratio of the lithium secondary batteries of Examples 1 to 2 was smaller than that of Comparative Examples 1 to 7 even if the number of cycles increased. In particular, in the lithium secondary battery of Example 1, there was almost no change in the discharge capacity according to the number of cycles compared to the discharge capacity of one cycle.

Experimental Example 3: Characterization of lithium secondary battery (2)

When the life characteristics of the lithium secondary battery were evaluated at 45 ° C., the initial voltage drop was measured every 5 cycles for 0 to 60 seconds, and the resistance was calculated by dividing by the current (0.3C). As a result, in Example 1, initial stage DC resistance DCIR was 10.6 m (ohm) at 45 degreeC.

Referring to FIG. 2, since the lithium secondary batteries prepared in Examples 1 to 2 have a lower DC resistance increase rate than the lithium secondary batteries prepared in Comparative Examples 1 to 7, it can be expected to exhibit excellent output density therefrom.

Experimental Example  4: Characterization of lithium secondary battery (3)

The lithium secondary batteries prepared in Examples 1 to 2 and Comparative Examples 1 to 3 and 6 were charged to 4.25V with a constant current of 0.3C, respectively, and then stored at 60 ° C. for 6 weeks. The amount of gas generated inside the lithium secondary battery over time was measured and shown in FIG. 3. The amount of gas generated in the lithium secondary battery was measured by the volume change of the lithium secondary battery.

Referring to FIG. 3, it was confirmed that the gas amount of the lithium secondary batteries prepared in Examples 1 to 2 was significantly lower than that of the lithium secondary batteries prepared in Comparative Examples 1 to 3 and 6.

Claims (15)

1. A core comprising a lithium composite metal oxide; And

   Located on the core, and comprises a surface treatment layer containing an amorphous oxide containing lithium (Li), boron (B) and aluminum (Al),

   The surface treatment layer includes an amorphous oxide in which lithium oxide, boron oxide and aluminum oxide are chemically bonded to each other,

   The amorphous oxide in the surface treatment layer, the content of aluminum oxide than the content of boron oxide, the lithium by-product present on the surface is less than 0.55% by weight relative to the total weight, the positive electrode active material for secondary batteries.
2. The method according to claim 1,

   The lithium composite metal oxide is a cathode active material for a secondary battery represented by Formula 1 below:

   <Formula 1>

   Li _a (Ni _x Co _y M1 _z ) _b M2 _c O ₂

   In Chemical Formula 1,

   M1 is at least one element selected from the group consisting of Mn and Al,

   M2 is at least one element selected from the group consisting of Ba, Ca, Zr, Ti, Mg, Ta, Nb and Mo,

   1≤a≤1.5, 0.9≤b≤1, 0≤c≤0.1, 0.6≤x <1, 0 <y <0.4, 0 <z≤0.4, b + c = 1.
3. The method according to claim 1,

   The molar ratio of the boron oxide and aluminum oxide is greater than 1: 1 ~ less than 2.5 positive electrode active material for secondary batteries.
4. The method according to claim 1,

   The surface treatment layer is a cathode active material for a secondary battery comprising an amorphous oxide containing Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ .
5. The method according to claim 4,

   Li ₂ O, B ₂ O ₃ and Al ₂ O ₃ is a positive electrode active material for a secondary battery that is chemically bonded to each other.
6. The method according to claim 1,

   The average thickness of the surface treatment layer is a cathode active material for secondary batteries 20 to 100nm.
7. The method according to claim 1,

   The cathode active material is a cathode active material for a secondary battery having an average particle diameter (D ₅₀ ) of 1㎛ to 20㎛.
8. The method according to claim 1,

   The lithium composite metal oxide is secondary particles formed by aggregation of primary particles,

   The cathode active material further comprising having a segregated phase of Zr oxide at the surface of secondary particles or grain boundaries between primary particles.
9. A first step of preparing a mixture by mixing a lithium composite metal oxide, a boron-containing raw material and an aluminum-containing raw material; And

   And heat treating the mixture under an oxygen atmosphere to form a surface treatment layer including an amorphous oxide on the core including the lithium composite metal oxide.

   The amorphous oxide is formed by reacting lithium by-products present on the surface of the lithium composite metal oxide with the boron-containing raw material and aluminum-containing raw material to form an amorphous oxide including lithium, boron, and aluminum. ,

   The content of the aluminum-containing raw material is more than 1 times and less than 2.5 times more than the content of the boron-containing raw material, the heat treatment is carried out at 500 ℃ to 800 ℃, a method for producing a positive electrode active material for secondary batteries .
10. The method according to claim 9,

    A method for producing a cathode active material for secondary batteries, wherein 0.1 to 0.8 parts by weight of the boron-containing raw material and 0.1 to 1 part by weight of the aluminum raw material are mixed with respect to 100 parts by weight of the lithium composite metal oxide.
11. The method according to claim 9,

    The boron-containing raw material is at least one secondary selected from the group consisting of H ₃ BO ₃ , HBPO ₄ , B ₂ O ₃ , B ₂ O ₅ , Li ₂ B ₄ O ₇ and (NH ₄ ) ₂ B ₄ O ₇ Method for producing a cathode active material for batteries.
12. The method according to claim 9,

    The aluminum-containing raw material is Al (OH) ₃ , Al ₂ (SO ₄ ) ₃ , AlCl ₃ And Al (NO ₃ ) _{3 A} method for producing a positive electrode active material for secondary batteries which is one or more selected from the group consisting of.
13. The method according to claim 9,

    The lithium by-product is a method for producing a positive electrode active material for a secondary battery is at least one selected from the group consisting of LiOH and Li ₂ CO ₃ .
14. A secondary battery positive electrode comprising the positive electrode active material according to claim 1.
15. Secondary battery comprising a cathode active material according to claim 14.

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