Composite cathode active material, Cathode and Lithium battery containing composite cathode active material and Preparation method thereof

Abstract

A core comprising a lithium transition metal oxide; and a shell disposed along the surface of the core; wherein the shell has the chemical formula MaOb(0 <a≤3, 0<b<4, a가 1, 2, 또는 3 이면, b는 정수가 아님)로 표시되는 1종 이상의 제1 금속산화물; 탄소계 재료; 및 도핑된 불소(F) 원소를 포함하며, 상기 제1 금속산화물이 탄소계 재료 메트릭스 내에 배치되며, 상기 M은 원소주기율표 2족 내지 13족, 제15족 및 16족 중에서 선택된 하나 이상의 금속인, 복합양극활물질, 이를 포함하는 양극과 리튬전지 및 복합양극활물질 제조방법이 제공된다.

Description

Technology Field

[0001] The invention relates to a composite cathode active material, a cathode employing the same, a lithium battery, and a method for manufacturing the same. Background Technology

[0002] To meet the demands for miniaturization and high performance in various devices, high energy density is becoming important in addition to the miniaturization and weight reduction of lithium batteries. In other words, high-capacity lithium batteries are becoming crucial.

[0003] In order to realize a lithium battery suitable for the above application, a cathode active material having a high capacity is being considered.

[0004] Conventional nickel-based cathode active materials suffered from reduced lifespan characteristics due to side reactions and poor thermal stability.

[0005] Therefore, a method is required that can prevent the degradation of battery performance while including a nickel-based cathode active material. The problem to be solved

[0006] One aspect is to provide a new composite cathode active material that can prevent the degradation of lithium performance by suppressing side reactions of the composite cathode active material and improving the reversibility of the electrode reaction.

[0007] Another aspect is to provide a cathode comprising the above-mentioned composite cathode active material.

[0008] Another aspect is to provide a lithium battery employing the above-mentioned positive electrode.

[0009] Another aspect is to provide a method for manufacturing the above-mentioned composite cathode active material. means of solving the problem

[0010] Depending on one aspect

[0011] A core comprising a lithium transition metal oxide; and

[0012] It includes a shell disposed along the surface of the core; and

[0013] The above shell is the chemical formula M a O b(0 <a≤3, 0<b<4, a가 1, 2, 또는 3 이면, b는 정수가 아님)로 표시되는 1종 이상의 제1 금속산화물; 탄소계 재료; 및 도핑된 불소(F) 원소를 포함하며,

[0014] A composite cathode active material is provided, wherein the first metal oxide is disposed within a carbon-based material matrix, and M is one or more metals selected from groups 2 to 13, group 15, and group 16 of the periodic table.

[0015] Depending on the other aspect

[0016] A cathode comprising the above composite cathode active material is provided.

[0017] According to another aspect,

[0018] A lithium battery including the above positive electrode is provided.

[0019] According to another aspect

[0020] A step of providing a lithium transition metal oxide;

[0021] Step of providing a complex; and

[0022] The method includes the step of mechanically milling the lithium transition metal oxide and the composite;

[0023] The above complex is formula M a O b (0 <a≤3, 0<b<4, a가 1, 2, 또는 3 이면, b는 정수가 아님)로 표시되는 1종 이상의 제1 금속산화물; 탄소계 재료; 및 도핑된 불소(F) 원소를 포함하며,

[0024] A method for manufacturing a composite cathode active material is provided, wherein the first metal oxide is disposed within a carbon-based material matrix, and M is one or more metals selected from groups 2 to 13, group 15, and group 16 of the periodic table. Effects of the invention

[0025] According to one aspect, the high-temperature cycle characteristics and high-rate characteristics of the lithium battery are improved by the composite cathode active material having a shell comprising a first metal oxide, a carbon-based material, and a doped fluorine (F) element. Brief explanation of the drawing

[0026] Figure 1 is the XPS spectrum of the undoped composite prepared in Comparative Example 1 and the fluorine (F) element-doped composite prepared in Comparative Example 1. Figure 2 is a schematic diagram of a lithium battery according to one embodiment. <Explanation of symbols for major parts of the drawing> 1: Lithium battery 2: Negative electrode 3: Anode 4: Separator 5: Battery case 6: Cap assembly Specific details for implementing the invention

[0027] The present inventive concept described below is subject to various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present inventive concept to specific embodiments and should be understood to include all modifications, equivalents, or substitutions that fall within the scope of the description of the present inventive concept.

[0028] The terms used below are used merely to describe specific embodiments and are not intended to limit the creative concept. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the following, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, components, materials, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, components, materials, or combinations thereof. The " / " used below may be interpreted as "and" or "or" depending on the context.

[0029] In the drawings, thicknesses have been enlarged or reduced to clearly represent various layers and regions. Throughout the specification, the same reference numerals have been used for similar parts. Throughout the specification, when a part such as a layer, film, region, or plate is described as being "on" or "above" another part, this includes not only cases where it is directly above another part but also cases where there is another part in between. Throughout the specification, terms such as "first," "second," etc., may be used to describe various components, but the components should not be limited by these terms. The terms are used solely for the purpose of distinguishing one component from another.

[0030] A composite cathode active material according to exemplary embodiments, a cathode and a lithium battery including the same, and a method for manufacturing the same will be described in more detail below.

[0031] The composite cathode active material comprises a core containing a lithium transition metal oxide; and a shell disposed along the surface of the core, wherein the shell has the chemical formula M a O b(0 <a≤3, 0<b<4, a가 1, 2, 또는 3 이면, b는 정수가 아님)로 표시되는 1종 이상의 제1 금속산화물; 탄소계 재료; 및 도핑된 불소(F) 원소를 포함하며, 상기 제1 금속산화물이 탄소계 재료 메트릭스 내에 배치되며, 상기 M은 원소주기율표 2족 내지 13족, 제15족 및 16족 중에서 선택된 하나 이상의 금속이다.

[0032] The theoretical basis for the excellent effect provided by the composite cathode active material according to one embodiment is explained below; however, this is intended to aid in understanding the creative concept and is not intended to limit the creative concept in any way.

[0033] A shell comprising a first metal oxide, a carbon-based material, and a fluorine (F) element is disposed on the core of a composite cathode active material. The fluorine (F) element contained in the shell is a fluorine (F) element doped into the shell. The fluorine (F) element doped into the shell forms chemical bonds with the carbon-based material and / or the first metal oxide contained in the shell. The fluorine (F) element doped into the shell is distinguished from the fluorine (F) element physically disposed around the composite cathode active material. The fluorine (F) element doped into the shell is distinguished from the fluorine (F) element disposed around the composite cathode active material by, for example, mixing the composite cathode active material with a fluorine (F)-containing compound or a composition containing it (e.g., a binder, a conductive material, an electrolyte, etc.). Fluorine (F) atoms increase electrochemical reactivity and electrical conductivity by having lower electronegativity compared to carbon (C) atoms. Therefore, in a shell containing carbon-based materials as the main component, for example, the CF bond between the carbon-based material and fluorine atoms facilitates the conduction of electrons and ions. Thus, it can assist in the electrochemical absorption and release of high-density energy in the composite cathode active material. For example, the inclusion of fluorine (F) elements within the shell can increase the density of charge carriers by adding electrons from the fluorine (F) elements to, for example, the π-electron system of the carbon-based material. Consequently, the inclusion of doped fluorine (F) elements in the shell can increase the reversibility of the electrode reaction on the surface of the composite cathode active material and increase the conductivity of the electrode. As a result, the cycle characteristics and charge / discharge capacity of a battery containing such a composite cathode active material can be improved.

[0034] Conventional carbon-based materials easily aggregate, making it difficult to apply a uniform coating on the core. In contrast, the composite cathode active material uses a carbon-based material matrix and a composite containing a plurality of first metal oxides disposed within it, thereby preventing the aggregation of the carbon-based material and allowing a uniform shell to be disposed on the core. Consequently, by effectively blocking contact between the core and the electrolyte, side reactions caused by contact between the core and the electrolyte are prevented. Furthermore, the formation of a resistive layer is suppressed by inhibiting cation mixing by the electrolyte. Additionally, the leaching of transition metal ions is also suppressed. The carbon-based material may be, for example, a crystalline carbon-based material. The carbon-based material may be, for example, a carbon-based nanostructure. The carbon-based material may be, for example, a carbon-based two-dimensional nanostructure. The carbon-based material may be, as an example, graphene. In this case, the shell containing graphene and / or its matrix is ​​flexible, allowing it to easily accommodate volume changes of the composite cathode active material during charging and discharging, thereby suppressing the occurrence of cracks within the composite cathode active material. Since graphene has high electronic conductivity, the interfacial resistance between the composite cathode active material and the electrolyte is reduced. Consequently, the internal resistance of the lithium battery is maintained or reduced despite the introduction of a shell containing graphene.

[0035] Since the carbon-based material included in the shell of the composite cathode active material is derived from a graphene matrix, it has a relatively lower density and higher porosity compared to conventional carbon-based materials derived from graphite-based materials. The d002 interplanar distance of the carbon-based material included in the shell of the composite cathode active material may be, for example, 3.38 Å or more, 3.40 Å or more, 3.45 Å or more, 3.50 Å or more, 3.60 Å or more, 3.80 Å or more, or 4.00 Å or more. The d002 interplanar distance of the carbon-based material included in the shell of the composite cathode active material may be, for example, 3.38 to 4.0 Å, 3.38 to 3.8 Å, 3.38 to 3.6 Å, 3.38 to 3.5 Å, or 3.38 to 3.45 Å. In contrast, the d002 interplanar distance of a conventional carbon-based material derived from a graphite-based material may be, for example, 3.38 Å or less, or 3.35 to 3.38 Å.

[0036] Since the first metal oxide has dielectric strength, it can prevent the degradation of the lithium transition metal oxide contained in the core during charging and discharging at high voltage. The shell may include, for example, one type of first metal oxide or two or more different types of first metal oxides.

[0037] As a result, the high-rate characteristics of the lithium battery containing the aforementioned composite cathode active material are improved, and the high-temperature and high-voltage cycle characteristics are improved.

[0038] In the composite cathode active material, for example, the shell content is 0.5 wt% to 3 wt%, 0.5 wt% to 2.5 wt%, 0.5 wt% to 2 wt%, or 0.5 wt% to 1.5 wt% of the total weight of the composite cathode active material. In addition, the content of the first metal oxide may be, for example, 0.3 wt% to 1.8 wt%, 0.3 wt% to 1.5 wt%, 0.3 wt% to 1.2 wt%, or 0.3 wt% to 0.9 wt% of the total weight of the composite cathode active material. The cycle characteristics of the lithium battery are further improved by the composite cathode active material each comprising a shell and a first metal oxide within these content ranges. The content of the doped fluorine (F) element included in the shell may be, for example, 1 to 10 at%, 1 to 9 at%, 2 to 9 at%, 2 to 8 at%, 3 to 8 at%, 3 to 7 at%, 4 to 7 at%, or 4 to 6 at% relative to the total number of atoms in the shell. The cycle characteristics of the lithium battery including the composite cathode active material may be further improved by doping the shell with a fluorine (F) element having these content ranges. The content of the doped fluorine (F) element included in the shell can be determined, for example, from the peak obtained by measuring the XPS spectrum on the surface of the composite cathode active material.

[0039] The content of the first metal included in the shell may be, for example, 1 to 10 at%, 1 to 9 at%, 2 to 9 at%, 2 to 8 at%, 3 to 8 at%, 3 to 7 at%, 4 to 7 at%, or 4 to 6 at% with respect to the total number of atoms of the shell. By including the first metal having such a content range in the shell, the cycle characteristics of the lithium battery including the composite cathode active material may be further improved. The content of the first metal element included in the shell can be obtained, for example, from the peaks obtained by measuring the XPS spectrum on the surface of the composite cathode active material.

[0040] The oxygen (O) content contained in the shell may be, for example, 1 to 20 at%, 1 to 18 at%, 3 to 18 at%, 3 to 16 at%, 5 to 16 at%, 5 to 14 at%, 7 to 14 at%, or 7 to 12 at% relative to the total number of atoms in the shell. By including oxygen having such a content range in the shell, the cycle characteristics of a lithium battery containing a composite cathode active material may be further improved. The oxygen (O) content contained in the shell can be obtained, for example, from a peak obtained by measuring the XPS spectrum on the surface of the composite cathode active material.

[0041] The shell may additionally contain other elements in addition to fluorine (F), the first metal, and oxygen. The additional elements contained in the shell are, for example, nitrogen (N) and boron (B). These additional elements may be included together with the fluorine (F) element in the precursor during the manufacturing process of the composite cathode active material.

[0042] The nitrogen (N) content contained in the shell may be, for example, 1 to 12 at%, 2 to 12 at%, 2 to 11 at%, 3 to 11 at%, 3 to 10 at%, 4 to 10 at%, 4 to 9 at%, 5 to 9 at%, 5 to 8 at%, or 5 to 7 at% with respect to the total number of atoms in the shell. By including nitrogen having such a content range in the shell, the cycle characteristics of a lithium battery containing a composite cathode active material may be further improved. The nitrogen (N) content contained in the shell can be obtained, for example, from a peak obtained by measuring the XPS spectrum on the surface of the composite cathode active material.

[0043] The boron (B) content contained in the shell may be, for example, greater than 0 to 5 at%, 0.01 to 4 at%, 0.1 to 3 at%, 0.1 to 2 at%, 0.1 to 1.5 at%, or 0.3 to 1 at% relative to the total number of atoms in the shell. By including boron (B) having such a content range in the shell, the cycle characteristics of the lithium battery containing the composite cathode active material may be further improved. The boron (B) content contained in the shell can be obtained, for example, from the peaks obtained by measuring the XPS spectrum on the surface of the composite cathode active material.

[0044] The carbon content of the shell may be, for example, 65 to 99 at%, 70 to 99 at%, 75 to 99 at%, 80 to 99 at%, 80 to 95 at%, 80 to 93 at%, 80 to 91 at%, or 83 to 90 at% with respect to the total number of atoms of the shell. By including carbon having such a content range in the shell, the cycle characteristics of a lithium battery containing a composite cathode active material may be further improved. The carbon content of the shell can be determined, for example, from the peaks obtained by measuring the XPS spectrum on the surface of the composite cathode active material.

[0045] The metal included in the first metal oxide may be, for example, one or more selected from Al, Nb, Mg, Sc, Ti, Zr, V, W, Mn, Fe, Co, Pd, Cu, Ag, Zn, Sb, and Se. The first metal oxide is, for example, Al2O z (0 <z<3), NbO x (0 <x<2.5), MgO x (0 <x<1), Sc2O z (0 <z<3), TiO y (0 <y<2), ZrO y (0 <y<2), V2O z (0 <z<3), WO y (0 <y<2), MnO y (0 <y<2), Fe2O z(0 <z<3), Co3O w (0 <w<4), PdO x (0 <x<1), CuO x (0 <x<1), AgO x (0 <x<1), ZnO x (0 <x<1), Sb2O z (0 <z<3), 및 SeO y (0 <y<2) 중에서 선택된 하나 이상일 수 있다. 탄소계 재료의 메트릭스 내에 이러한 제1 금속산화물이 배치됨에 의하여 코어 상에 배치된 쉘의 균일성이 향상되고, 복합양극활물질의 내전압성이 더욱 향상된다. 예를 들어, 쉘은 제1 금속산화물로서 Al2O x (0 <x<3)를 포함한다.

[0046] Shell is the chemical formula M a O c (0 <a≤3, 0<c≤4, a가 1, 2, 또는 3이면, c는 정수임)로 표시되는 1종 이상의 제2 금속산화물을 더 포함할 수 있다. 상기 M은 원소주기율표 2족 내지 13족, 제15족 및 16족 중에서 선택된 하나 이상의 금속이다. 예를 들어, 제2 금속산화물은 상기 제1 금속산화물과 동일한 금속을 포함하며, 제2 금속산화물의 a 와 c의 비율인 c / a가 상기 제1 금속산화물의 a 와 b의 비율인 b / a에 비하여 더 큰 값을 가진다. 예를 들어, c / a > b / a. The second metal oxide is selected from, for example, Al2O3, NbO, NbO2, Nb2O5, MgO, Sc2O3, TiO2, ZrO2, V2O3, WO2, MnO2, Fe2O3, Co3O4, PdO, CuO, AgO, ZnO, Sb2O3, and SeO2. The first metal oxide is a reduction product of the second metal oxide. The first metal oxide is obtained by reducing part or all of the second metal oxide. Thus, the first metal oxide has a lower oxygen content and a higher oxidation number of the metal compared to the second metal oxide. For example, the shell is Al2O, which is the first metal oxide. x(0 <x<3) 및 제2 금속산화물인 Al2O3를 포함한다.

[0047] In a composite cathode active material, for example, the carbon-based material contained in the shell and the transition metal of the lithium transition metal oxide contained in the core are chemically bound through chemical bonding. The carbon atoms (C) of the carbon-based material contained in the shell and the transition metal (Me) of the lithium transition metal oxide are chemically bound through CO-Me bonds (e.g., CO-Ni bonds, or CO-Co bonds) mediated by oxygen atoms. The core and the shell are composited by the chemical bonding of the carbon-based material contained in the shell and the lithium transition metal oxide contained in the core through chemical bonding. Therefore, it is distinguished from a simple physical mixture of the carbon-based material and the lithium transition metal oxide.

[0048] In addition, the first metal oxide and carbon-based material contained in the shell are also chemically bound through chemical bonding. Here, the chemical bonding is, for example, a covalent bond or an ionic bond. A covalent bond is a bond comprising, for example, at least one of an ester group, an ether group, a carbonyl group, an amide group, a carbonate anhydride group, and an acid anhydride group. An ionic bond is a bond comprising, for example, a carboxylate ion, an ammonium ion, an acyl cation group, etc.

[0049] The thickness of the shell is, for example, 1 nm to 5 µm, 1 nm to 1 µm, 1 nm to 500 nm, 1 nm to 200 nm, 1 nm to 100 nm, 1 nm to 90 nm, 1 nm to 80 nm, 1 nm to 70 nm, 1 nm to 60 nm, 1 nm to 50 nm, 1 nm to 40 nm, 1 nm to 30 nm, or 1 nm to 20 nm. By having the shell within this range of thickness, the conductivity of the electrode containing the composite cathode active material is improved.

[0050] The composite cathode active material may further include, for example, a third metal doped onto a core or a third metal oxide coated onto the core. And, the shell may be disposed on the doped third metal or the coated third metal oxide. For example, after the third metal is doped onto the surface of a lithium transition metal oxide included in the core or the third metal oxide is coated onto the surface of a lithium transition metal oxide, the shell may be disposed on the third metal and / or the third metal oxide. For example, the composite cathode active material comprises a core; an intermediate layer disposed on the core; and a shell disposed on the intermediate layer, wherein the intermediate layer may include a third metal or a third metal oxide. The third metal is one or more metals selected from Al, Zr, W, and Co, and the third metal oxide may be Al2O3, Li2O-ZrO2, WO2, CoO, Co2O3, Co3O4, etc.

[0051] The shell comprising the composite cathode active material comprises, for example, one or more selected from a composite comprising a first metal oxide, a carbon-based material, for example graphene, and a doped fluorine (F) element, and a milling result of said composite, wherein the first metal oxide is disposed within a matrix of the carbon-based material, for example graphene matrix. The shell is manufactured, for example, from a composite comprising a first metal oxide, a carbon-based material, for example graphene, and a doped fluorine (F) element. The composite may further comprise a second metal oxide in addition to the first metal oxide. The composite may, for example, comprise two or more first metal oxides. The composite may, for example, comprise two or more first metal oxides and two or more second metal oxides.

[0052] The content of one or more of the composite and the milling product thereof included in the composite cathode active material may be 3 wt% or less, 2 wt% or less, 1 wt% or less, 0.5 wt% or less, or 0.2 wt% or less of the total weight of the composite cathode active material. The content of one or more of the composite and the milling product thereof may be 0.01 wt% to 3 wt%, 0.01 wt% to 1 wt%, 0.01 wt% to 0.7 wt%, 0.01 wt% to 0.5 wt%, 0.01 wt% to 0.2 wt%, 0.01 wt% to 0.1 wt%, or 0.03 wt% to 0.07 wt% of the total weight of the composite cathode active material. The cycle characteristics of a lithium battery containing a composite cathode active material are further improved by the composite cathode active material including one or more of the composites of this range and the milling products thereof.

[0053] The content of the doped fluorine (F) element contained in the composite may be, for example, 1 to 10 at%, 1 to 9 at%, 2 to 9 at%, 2 to 8 at%, 3 to 8 at%, 3 to 7 at%, 4 to 7 at%, or 4 to 6 at% relative to the total number of atoms of the composite. By doping the composite with a fluorine (F) element having such a content range, the cycle characteristics of a lithium battery employing a composite cathode active material having a shell comprising the composite and / or the milling product thereof may be further improved. The content of the doped fluorine (F) element contained in the composite can be obtained, for example, from a peak obtained by measuring an XPS spectrum on the surface of the composite or on the surface of the composite cathode active material coated with the composite.

[0054] One or more average particle sizes selected from the first metal oxide and the second metal oxide included in the composite may be 1 nm to 1 µm, 1 nm to 500 nm, 1 nm to 200 nm, 1 nm to 100 nm, 1 nm to 70 nm, 1 nm to 50 nm, 1 nm to 30 nm, 3 nm to 30 nm, 3 nm to 25 nm, 5 nm to 25 nm, 5 nm to 20 nm, 7 nm to 20 nm, or 7 nm to 15 nm. By having particle sizes in this nano range, the first metal oxide and / or the second metal oxide can be distributed more uniformly within the carbon-based material matrix of the composite. Thus, the composite can be uniformly coated on the core without aggregation to form a shell. Additionally, by having particle sizes in this range, the first metal oxide and / or the second metal oxide can be arranged more uniformly on the core. Therefore, by uniformly distributing the first metal oxide and / or the second metal oxide on the core, the withstand voltage characteristics can be exhibited more effectively.

[0055] The average particle size of the first metal oxide and the second metal oxide is measured using a measuring device, for example, a laser diffraction method or a dynamic light scattering method. The average particle size is measured using a laser scattering particle size distribution meter (e.g., Horibasa LA-920), and is the value of the median particle size (D50) when 50% is accumulated from the small particle side in volume conversion.

[0056] One or more selected from the first metal oxide and the second metal oxide included in the composite may have a uniformity deviation of 3% or less, 2% or less, or 1% or less. The uniformity can be determined, for example, by XPS. Accordingly, one or more selected from the first metal oxide and the second metal oxide may be uniformly distributed within the composite with a deviation of 3% or less, 2% or less, or 1% or less.

[0057] The carbon-based material included in the composite has, for example, a branched structure, and one or more metal oxides selected from a first metal oxide and a second metal oxide may be distributed within the branched structure of the carbon-based material. The branched structure of the carbon-based material includes, for example, a plurality of carbon-based material particles in contact with each other. By having a branched structure, the carbon-based material can provide various conductive paths.

[0058] The carbon-based material included in the composite may be, for example, graphene. The graphene may have, for example, a branched structure, and one or more metal oxides selected from a first metal oxide and a second metal oxide may be distributed within the branched structure of the graphene. The branched structure of the graphene may include, for example, a plurality of graphene particles in contact with each other. By having a branched structure, the graphene can provide various conductive pathways.

[0059] The carbon-based material included in the composite has, for example, a spherical structure, and one or more metal oxides selected from the first metal oxide and the second metal oxide may be distributed within the spherical structure. The size of the spherical structure of the carbon-based material may be 50 nm to 300 nm. There may be multiple carbon-based materials having a spherical structure. As the carbon-based material has a spherical structure, the composite may have a rigid structure.

[0060] The carbon-based material included in the composite may be, for example, graphene. The graphene may have, for example, a spherical structure, and one or more metal oxides selected from a first metal oxide and a second metal oxide may be distributed within the spherical structure. The size of the spherical structure of the graphene may be 50 nm to 300 nm. There may be multiple graphenes having a spherical structure. As the graphene has a spherical structure, the composite may have a rigid structure.

[0061] The carbon-based material included in the composite has, for example, a spiral structure in which a plurality of spherical structures are connected, and one or more metal oxides selected from the first metal oxide and the second metal oxide may be distributed within the spherical structure of the spiral structure. The size of the spiral structure of the carbon-based material may be 500 nm to 100 μm. Since the carbon-based material has a spiral structure, the composite may have a rigid structure.

[0062] The carbon-based material included in the composite may be, for example, graphene. The graphene may have, for example, a spiral structure in which a plurality of spherical structures are connected, and one or more metal oxides selected from a first metal oxide and a second metal oxide may be distributed within the spherical structure of the spiral structure. The size of the spiral structure of the graphene may be 500 nm to 100 µm. As the graphene has a spiral structure, the composite may have a rigid structure.

[0063] The carbon-based material included in the composite has, for example, a cluster structure in which a plurality of spherical structures are aggregated, and one or more metal oxides selected from the first metal oxide and the second metal oxide may be distributed within the spherical structure of the cluster structure. The size of the cluster structure of the carbon-based material may be 0.5 mm to 10 cm. As the carbon-based material has a cluster structure, the composite may have a rigid structure.

[0064] The carbon-based material included in the composite may be, for example, graphene. The graphene may have a cluster structure in which a plurality of spherical structures are aggregated, for example, and one or more metal oxides selected from a first metal oxide and a second metal oxide may be distributed within the spherical structure of the cluster structure. The size of the cluster structure of the graphene may be 0.5 mm to 10 cm. As the graphene has a cluster structure, the composite may have a rigid structure.

[0065] The composite is, for example, a faceted-ball structure, and one or more selected from a first metal oxide and a second metal oxide may be distributed inside or on the surface of the structure. Since the composite is such a faceted-ball structure, the composite can be easily coated on the irregular surface irregularities of the core.

[0066] The composite is, for example, a planar structure, and one or more selected from the first metal oxide and the second metal oxide may be distributed inside or on the surface of the structure. Since the composite is such a two-dimensional planar structure, the composite can be easily coated on the irregular surface irregularities of the core.

[0067] The carbon-based material included in the composite extends from the first metal oxide by a distance of 10 nm or less and may include at least 1 to 20 layers of carbon-based material. For example, a carbon-based material having a total thickness of 12 nm or less may be disposed on the first metal oxide by stacking a plurality of layers of carbon-based material. For example, the total thickness of the carbon-based material may be 0.6 to 12 nm.

[0068] The carbon-based material included in the composite may be, for example, graphene. The graphene may extend from the first metal oxide by a distance of 10 nm or less and may include at least 1 to 20 graphene layers. For example, graphene having a total thickness of 12 nm or less may be disposed on the first metal oxide by stacking a plurality of graphene layers. For example, the total thickness of the graphene may be 0.6 to 12 nm.

[0069] The core included in the composite cathode active material comprises, for example, a lithium transition metal oxide represented by the following chemical formula 1:

[0070] <Chemical Formula 1>

[0071] Li a Ni x Co y M z O 2-b A b

[0072] In the above chemical formula 1,

[0073] 0.9≤a≤1.2, 0.8≤x≤0.95, 0≤y≤0.2, 0 <z≤0.2, 및 x+y+z=1이고,

[0074] M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), or a combination thereof,

[0075] A is F, S, Cl, Br, or a combination thereof.

[0076] The core included in the composite cathode active material comprises, for example, a lithium transition metal oxide represented by the following chemical formulas 2 to 4:

[0077] <Chemical Formula 2>

[0078] LiNi x Co y Mn z O2

[0079] <Chemical Formula 3>

[0080] LiNi x Co y Al z O2

[0081] In the above chemical formulas 2 to 3, 0.8≤x≤0.95, 0 <y≤0.2, 0<z≤0.2 및 x+y+z=1이다.

[0082] <Chemical Formula 4>

[0083] LiNi x Co y Mn v Al w O2

[0084] In the above chemical formula 4, 0.8≤x≤0.95, 0 <y≤0.2, 0<v≤0.2, 0<w≤0.2, 및 x+y+v+w=1이다.

[0085] Lithium transition metal oxides of Formulas 1 to 4 can provide excellent initial capacity, room temperature lifetime characteristics, and high temperature lifetime characteristics while having a high nickel content of 80 mol% or more, 85 mol% or more, or 90 mol% or more relative to the total molar amount of transition metal. For example, the nickel content in the lithium transition metal oxides of Formulas 1 to 4 may be 80 mol% to 95 mol%, 85 mol% to 95 mol%, or 90 mol% to 95 mol% relative to the total molar amount of transition metal.

[0086] The core included in the composite cathode active material comprises, for example, a lithium transition metal oxide represented by the following chemical formulas 5 to 6:

[0087] <Chemical Formula 5>

[0088] Li a Co x M y O 2-b A b

[0089] In the above chemical formula 5,

[0090] 1.0≤a≤1.2, 0≤b≤0.2, 0.9≤x≤1, 0≤y≤0.1, and x+y=1, and

[0091] M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al) or a combination thereof, and A is F, S, Cl, Br or a combination thereof.

[0092] <Chemical Formula 6>

[0093] LiCoO2

[0094] A cathode according to another embodiment comprises the composite cathode active material described above. By including the composite cathode active material described above, the cathode provides improved cycle characteristics and increased conductivity.

[0095] The anode is manufactured, for example, by the following exemplary method, but is not necessarily limited to this method and is adjusted according to the required conditions.

[0096] First, a cathode active material composition is prepared by mixing the aforementioned composite cathode active material, conductive agent, binder, and solvent. The prepared cathode active material composition is directly coated and dried onto an aluminum current collector to manufacture a cathode electrode plate with a cathode active material layer formed thereon. Alternatively, the cathode active material composition is cast onto a separate support, and the film obtained by peeling it off from the support is laminated onto the aluminum current collector to manufacture a cathode electrode plate with a cathode active material layer formed thereon.

[0097] Conductive agents include carbon black, graphite fine particles, natural graphite, artificial graphite, acetylene black, Ketjen black, carbon fibers; carbon nanotubes; metal powders such as copper, nickel, aluminum, and silver, or metal fibers or metal tubes; conductive polymers such as polyphenylene derivatives, but are not limited to these, and any material used as a conductive material in the relevant technical field is acceptable.

[0098] As binders, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene (PTFE), mixtures of the aforementioned polymers, styrene butadiene rubber-based polymers, etc. are used, and as solvents, N-methylpyrrolidone (NMP), acetone, water, etc. are used, but are not necessarily limited to these and any solvent used in the relevant technical field is acceptable.

[0099] It is also possible to form pores inside the electrode plate by adding a plasticizer or a pore-forming agent to the positive electrode active material composition.

[0100] The content of the composite cathode active material, conductive agent, binder, and solvent used in the cathode is at a level typically used in lithium batteries. Depending on the application and composition of the lithium battery, one or more of the above conductive agent, binder, and solvent may be omitted.

[0101] The binder content included in the anode may be 0.1 to 10 wt% or 0.1 to 5 wt% of the total weight of the anode active material layer. The composite anode active material content included in the anode may be 90 wt% to 99 wt% or 95 wt% to 99 wt% of the total weight of the anode active material layer.

[0102] In addition, the anode may additionally include other general anode active materials in addition to the aforementioned composite anode active material.

[0103] A general cathode active material is a lithium-containing metal oxide, and any commonly used in the industry may be used without limitation. For example, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used, and specific examples include Li a A 1-b B b D2(wherein 0.90 ≤ a ≤ 1, and 0 ≤ b ≤ 0.5); Li a E 1-b B b O 2-c D c (In the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); LiE 2-b B b O 4-c D c (In the above equation, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B c D α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Co b B c O 2-α F α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Co b B c O 2-α F2(wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c D α(In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Mn b B c O 2-α F α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c O 2-α F2(wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni b E c G d O2(wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1); Li a Ni b Co c Mn d GeO2(wherein the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0.001 ≤ e ≤ 0.1); Li a NiG b O2(in the above equation, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a CoG b O2(in the above equation, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a MnG b O2(in the above equation, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4(wherein 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li (3-f)J2(PO4)3(0 ≤ f ≤ 2); Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2); compounds represented by any one of the chemical formulas of LiFePO4 may be used:

[0104] In the chemical formula representing the compound described above, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0105] It is possible to use a compound having a coating layer added to the surface of the compound described above, and it is also possible to use a mixture of the compound described above and the compound having a coating layer added. The coating layer added to the surface of the compound described above includes, for example, a coating element compound of an oxide, hydroxide, oxyhydroxide, oxycarbonate, or hydroxycarbonate of a coating element. The compound forming such a coating layer is amorphous or crystalline. The coating elements included in the coating layer are Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The method for forming the coating layer is selected within a range that does not adversely affect the physical properties of the cathode active material. The coating method is, for example, spray coating or immersion. Since the specific coating method is well understood by those skilled in the art, a detailed explanation will be omitted.

[0106] A lithium battery according to another embodiment employs a cathode comprising the composite cathode active material described above.

[0107] A lithium battery provides improved cycle characteristics and thermal stability by employing a cathode containing the aforementioned composite cathode active material.

[0108] Lithium batteries are manufactured, for example, by the following exemplary method, but are not necessarily limited to this method and are adjusted according to the required conditions.

[0109] First, an anode is manufactured according to the anode manufacturing method described above.

[0110] Next, the cathode is manufactured as follows. The cathode is manufactured in substantially the same manner as the anode, except that, for example, a cathode active material is used instead of a composite anode active material. In addition, the conductive agent, binder, and solvent in the cathode active material composition may be substantially the same as those used in the anode.

[0111] For example, a negative electrode active material composition is prepared by mixing a negative electrode active material, a conductive agent, a binder, and a solvent, and a negative electrode plate is manufactured by directly coating this composition onto a copper current collector. Alternatively, the prepared negative electrode active material composition is cast onto a separate support, and a negative electrode active material film peeled from the support is laminated onto a copper current collector to manufacture a negative electrode plate.

[0112] Any negative electrode active material used as a negative electrode active material for lithium batteries in the relevant technical field is acceptable. For example, it includes one or more selected from the group consisting of lithium metal, metals alloyable with lithium, transition metal oxides, non-transition metal oxides, and carbon-based materials.

[0113] Metals that can be alloyed with lithium include, for example, Si, Sn, Al, Ge, Pb, Bi, Sb Si-Y alloys (wherein Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, and is not Si), Sn-Y alloys (wherein Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, and is not Sn), etc. The element Y is, for example, Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0114] The above transition metal oxides are, for example, lithium titanium oxide, vanadium oxide, lithium vanadium oxide, etc.

[0115] Non-transfer metal oxides are, for example, SnO2, SiO2 x (0 <x<2) 등이다.

[0116] Carbon-based materials are, for example, crystalline carbon, amorphous carbon, or mixtures thereof. Crystalline carbon is graphite, for example, amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite. Amorphous carbon is, for example, soft carbon (low-temperature calcined carbon) or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0117] The content of the negative electrode active material, conductive agent, binder, and solvent is at levels typically used in lithium batteries. Depending on the application and composition of the lithium battery, one or more of the above conductive agent, binder, and solvent may be omitted.

[0118] The binder content included in the cathode may be, for example, 0.1 to 10 wt% or 0.1 to 5 wt% of the total weight of the cathode active material layer. The conductive material content included in the cathode may be, for example, 0.1 to 10 wt% or 0.1 to 5 wt% of the total weight of the cathode active material layer. The cathode active material content included in the cathode may be, for example, 90 wt% to 99 wt% or 95 wt% to 99 wt% of the total weight of the cathode active material layer. When the cathode active material is lithium metal, the cathode may not include a binder and a conductive material.

[0119] Next, a separator to be inserted between the anode and cathode is prepared.

[0120] Any separator commonly used in lithium batteries is acceptable. For example, a separator is used that exhibits low resistance to electrolyte ion movement and excellent electrolyte wettability. The separator is selected from, for example, glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or combinations thereof, and is in the form of a nonwoven or woven fabric. For lithium-ion batteries, windable separators such as polyethylene or polypropylene are used, while for lithium-ion polymer batteries, separators with excellent organic electrolyte impregnation capabilities are used.

[0121] The separator is manufactured using the following exemplary method, but is not limited to this method and is adjusted according to the required conditions.

[0122] First, a separator composition is prepared by mixing a polymer resin, a filler, and a solvent. The separator composition is directly coated and dried on the electrode to form a separator. Alternatively, the separator composition is cast and dried on a support, and then a separator film peeled from the support is laminated onto the electrode to form a separator.

[0123] The polymer used in the manufacture of the separator is not particularly limited, and any polymer used as a binder for the electrode plate is acceptable. For example, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, or mixtures thereof are used.

[0124] Next, the electrolyte is prepared.

[0125] The electrolyte is, for example, an organic electrolyte. An organic electrolyte is prepared, for example, by dissolving a lithium salt in an organic solvent.

[0126] Any organic solvent used as an organic solvent in the relevant technical field is acceptable. Examples of organic solvents include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether, or mixtures thereof.

[0127] Any lithium salt used as a lithium salt in the relevant technical field is also acceptable. Examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, and LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2)(where x and y are natural numbers from 1 to 20), LiCl, LiI, or mixtures thereof, etc.

[0128] Alternatively, the electrolyte is a solid electrolyte. The solid electrolyte is not limited to, for example, boron oxide, lithium oxynitride, etc., and any material used as a solid electrolyte in the relevant technical field is acceptable. The solid electrolyte is formed on the cathode, for example, by a method such as sputtering, or a separate solid electrolyte sheet is laminated on the cathode.

[0129] Solid electrolytes are, for example, oxide-based solid electrolytes or sulfide-based solid electrolytes.

[0130] Solid electrolytes are, for example, oxide-based solid electrolytes. Oxide-based solid electrolytes are Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(O≤x<1, O≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li x Ti y (PO4)3(0 <x<2, 0<y<3), Li x Al y Ti z (PO4)3(0 <x<2, 0<y<1, 0<z<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1 0≤y≤1), Li x La yTiO3(0 <x<2, 0<y<3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 It is one or more selected from (M = Te, Nb, or Zr, where x is an integer from 1 to 10). Solid electrolytes are produced by sintering methods, etc. For example, oxide-based solid electrolytes include Li7La3Zr2O 12 (LLZO) and Li 3+x La3Zr 2-a M a O 12 It is a garnet-type solid electrolyte selected from (M doped LLZO, M=Ga, W, Nb, Ta, or Al, x is an integer from 1 to 10).

[0131] Sulfide-based solid electrolytes may comprise, for example, lithium sulfide, silicon sulfide, phosphorus sulfide, boron sulfide, or combinations thereof. Sulfide-based solid electrolyte particles may comprise Li2S, P2S5, SiS2, GeS2, B2S3, or combinations thereof. Sulfide-based solid electrolyte particles may be Li2S or P2S5. Sulfide-based solid electrolyte particles are known to have high lithium ion conductivity compared to other inorganic compounds. For example, sulfide-based solid electrolytes comprise Li2S and P2S5. When the sulfide solid electrolyte material constituting the sulfide-based solid electrolyte comprises Li2S-P2S5, the mixed molar ratio of Li2S to P2S5 may be, for example, in the range of about 50:50 to about 90:10. Additionally, Li3PO4, halogens, halogen compounds, Li 2+2x Zn 1??x GeO4("LISICON", 0≤x<1), Li 3+y PO 4-x N x( "LIPON", 0 <x<4, 0<y<3), Li 3.25 Ge 0.25 P 0.75S4("ThioLISICON"), Li2O-Al2O3-TiO2-P2O 5( Inorganic solid electrolytes prepared by adding "LATP" or similar materials to inorganic solid electrolytes of Li2S-P2S5, SiS2, GeS2, B2S3, or combinations thereof can be used as sulfide solid electrolytes. Non-limiting examples of sulfide solid electrolyte materials include Li2S-P2S5; Li2S-P2S5-LiX (X = halogen element); Li2S-P2S5-Li2O; Li2S-P2S5-Li2O-LiI; Li2S-SiS2; Li2S-SiS2-LiI; Li2S-SiS2-LiBr; Li2S-SiS2-LiCl; Li2S-SiS2-B2S3-LiI; Li2S-SiS2-P2S5-LiI; Li2S-B2S3; Li2S-P2S5-Z m S n (0 <m<10, 0<n<10, Z=Ge, Zn 또는 Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; 및 Li2S-SiS2-Li p MO q (0 <p<10, 0<q<10, M=P, Si, Ge, B, Al, Ga 또는 In)을 포함한다. 이와 관련하여, 황화물계 고체전해질 재료는 황화물계 고체전해질 물질의 원료 시작 물질(예를 들면, Li2S, P2S5, 등)을 용융 담금질법(melt quenching method), 기계적 밀링법 등에 의해 처리함으로써 제조될 수 있다. 또한, 소성(calcinations) 공정이 상기 처리 후에 수행될 수 있다. 황화물계 고체전해질은 비정질이거나, 결정질이거나, 이들이 혼합된 상태일 수 있다.

[0132] As shown in FIG. 2, an exemplary lithium battery (1) includes a positive electrode (3), a negative electrode (2), and a separator (4). The positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded and accommodated in a battery case (5). An organic electrolyte is injected into the battery case (5) and sealed with a cap assembly (6) to complete the lithium battery (1). The battery case (5) is cylindrical but is not necessarily limited to this shape and may be, for example, prismatic, thin-film, etc.

[0133] A pouch-type lithium battery comprises one or more battery structures. A separator is placed between the positive and negative electrodes to form the battery structure. The battery structures are stacked in a bicell structure, then impregnated with an organic electrolyte, housed in a pouch, and sealed to complete the pouch-type lithium battery.

[0134] Multiple lithium batteries are stacked to form a battery module and / or battery pack, and such battery modules and / or battery packs are used in all devices requiring high capacity and high output. For example, they are used in laptops, smartphones, electric vehicles, etc.

[0135] A lithium battery using a solid electrolyte may be a solid-state battery or an all-solid-state battery. A lithium battery using a solid electrolyte may additionally include a solid electrolyte in one or more of the positive electrode and the negative electrode. For example, in a lithium battery in which an electrolyte layer containing a sulfide-based solid electrolyte is disposed between the positive electrode and the negative electrode, one or more of the positive electrode and the negative electrode may include a sulfide-based solid electrolyte.

[0136] Due to their excellent lifespan and high-rate performance, lithium batteries are used in applications such as electric vehicles (EVs) and energy storage systems (ESS). For instance, they are used in hybrid vehicles, such as plug-in hybrid electric vehicles (PHEVs). Additionally, they are utilized in fields requiring large amounts of power storage, such as electric bicycles and power tools.

[0137] A method for manufacturing a composite cathode active material according to another embodiment comprises the steps of: providing a lithium transition metal oxide; providing a composite; and mechanically milling the lithium transition metal oxide and the composite, wherein the composite has the chemical formula M a O b (0 <a≤3, 0<b<4, a는 1, 2 또는 3이며, b는 정수가 아님)로 표시되는 1종 이상의 제1 금속산화물; 탄소계 재료; 및 도핑된 불소(F) 원소를 포함하며, 제1 금속산화물이 탄소계 재료 메트릭스 내에 배치되며, 상기 M은 원소주기율표 2족 내지 13족, 제15족 및 16족 중에서 선택된 하나 이상의 금속이다. 기계적으로 밀링하는 단계에서 밀링 방법은 특별히 한정되지 않으며, 리튬전이금속산화물과 복합체를 기계를 사용하여 접촉시키는 방법으로서 당해 기술 분야에서 사용 가능한 방법이라면 모두 가능하다.

[0138] A lithium transition metal oxide is provided. The lithium transition metal oxide is a compound represented by, for example, Chemical Formulas 1 to 6 described above.

[0139] The step of providing a composite comprises, for example, supplying a reaction gas consisting of a carbon source gas to a structure including a metal oxide and heat-treating it to provide an undoped composite; and the step of preparing a composite by mixing the undoped composite with a fluorine (F)-containing compound.

[0140] The step of providing the complex is, for example, M a O c (0 <a≤3, 0<c≤4, a가 1, 2 또는 3인 경우, b가 정수임)로 표시되는 1종 이상의 제2 금속산화물에 탄소 공급원 기체로 이루어진 반응 가스를 공급하고 열처리하여 미도핑 복합체를 제조하는 단계를 포함하며, 상기 M은 원소주기율표 2족 내지 13족, 제15족 및 16족 중에서 선택된 하나 이상의 금속이다.

[0141] The carbon source gas is a compound represented by the following chemical formula 7, or one or more mixed gases selected from the group consisting of a compound represented by the following chemical formula 7, a compound represented by the following chemical formula 8, and an oxygen-containing gas represented by the following chemical formula 9.

[0142] <Chemical Formula 7>

[0143] CnH (2n+2-a) [OH] a

[0144] In the above chemical formula 7, n is 1 to 20, and a is 0 or 1;

[0145] <Chemical Formula 8>

[0146] CnH 2n

[0147] In the above chemical formula 8, n is 2 to 6;

[0148] <Chemical Formula 9>

[0149] C x H y O z

[0150] In the above chemical formula 9, x is an integer of 0 or 1 to 20, y is an integer of 0 or 1 to 20, and z is 1 or 2.

[0151] The compound represented by Chemical Formula 7 and the compound represented by Chemical Formula 8 are one or more selected from the group consisting of methane, ethylene, propylene, methanol, ethanol, and propanol. The oxygen-containing gas represented by Chemical Formula 9 includes, for example, carbon dioxide (CO2) and carbon monoxide (CO), water vapor (H2O), or a mixture thereof.

[0152] M a O c (0 <a≤3, 0<c≤4, a가 1, 2, 또는 3이면, c는 정수임)로 표시되는 제2 금속산화물에 탄소 공급원 기체로 이루어진 반응 가스를 공급하고 열처리하는 단계 이후에 질소, 헬륨 및 아르곤으로 이루어진 군으로부터 선택된 하나 이상의 불활성 기체를 이용한 냉각 단계를 더 거칠 수 있다. 냉각 단계는 상온(20-25℃)으로 조절하는 단계를 말한다. 탄소 공급원 기체는 질소, 헬륨, 아르곤으로 이루어진 군으로부터 선택된 하나 이상의 불활성 기체를 포함할 수 있다.

[0153] In the method for manufacturing composites, the process of growing carbon-based materials, such as graphene, according to a gas-phase reaction can be carried out under various conditions.

[0154] According to the first condition, for example, M a O c (0 <a≤3, 0<c≤4, a가 1, 2, 또는 3이면, c는 정수임)로 표시되는 제2 금속산화물이 배치된 반응기에 먼저 메탄을 공급하고 열처리온도(T)까지 승온처리한다. 열처리 온도(T)까지의 승온 시간은 10분 내지 4시간이고 열처리온도(T)는 700 내지 1100℃ 범위이다. 열처리온도(T)에서 반응 시간 동안 열처리를 실시한다. 반응시간은 예를 들어 4 내지 8시간이다. 열처리된 결과물을 상온으로 냉각시켜 복합체를 제조한다. 열처리온도(T)에서 상온까지 냉각하는 과정에 걸치는 시간은 예를 들어 1 내지 5 시간이다.

[0155] According to the second condition, for example, M a Oc (0 <a≤3, 0<c≤4, a가 1, 2, 또는 3이면, c는 정수임)로 표시되는 제2 금속산화물이 배치된 반응기에 먼저 수소를 공급하고 열처리온도(T)까지 승온 처리한다. 열처리 온도(T)까지의 승온 시간은 10분 내지 4시간이고 열처리온도(T)는 700 내지 1100℃ 범위이다. 열처리온도(T)에서 일정 반응 시간 동안 열처리한 후 메탄 가스를 공급하고 잔여 반응 시간 동안 열처리를 실시한다. 반응시간은 예를 들어 4 내지 8시간이다. 열처리된 결과물을 상온으로 냉각시켜 복합체를 제조한다. 냉각하는 과정에서 질소를 공급한다. 열처리온도(T)에서 상온까지 냉각하는 과정에 걸치는 시간은 예를 들어 1 내지 5시간이다.

[0156] According to the third condition, for example, M a O c (0 <a≤3, 0<c≤4, a가 1, 2, 또는 3이면, c는 정수임)로 표시되는 제2 금속산화물이 배치된 반응기에 먼저 수소를 공급하고 열처리온도(T)까지 승온 처리한다. 열처리 온도(T)까지의 승온 시간은 10분 내지 4시간이고 열처리온도(T)는 700 내지 1100℃ 범위이다. 열처리온도(T)에서 일정 반응 시간 동안 열처리한 후 메탄과 수소의 혼합 가스를 공급하고 잔여 반응 시간 동안 열처리를 실시한다. 반응시간은 예를 들어 4 내지 8시간이다. 열처리된 결과물을 상온으로 냉각시켜 복합체를 제조한다. 냉각하는과정에서 질소를 공급한다. 열처리온도(T)에서 상온까지 냉각하는 과정에 걸치는 시간은 예를 들어 1 내지 5 시간이다.

[0157] In the process of manufacturing the composite, if the carbon source gas contains water vapor, a composite having excellent conductivity can be obtained. The content of water vapor in the gas mixture is not limited and, for example, is 0.01 to 10 volume% based on 100 volume% of the total carbon source gas. The carbon source gas is, for example, methane; a mixed gas containing methane and an inert gas; or a mixed gas containing methane and an oxygen-containing gas.

[0158] The carbon source gas may be, for example, methane; a mixed gas of methane and carbon dioxide; or a mixed gas of methane, carbon dioxide, and water vapor. In the mixed gas of methane and carbon dioxide, the molar ratio of methane to carbon dioxide is about 1:0.20 to 1:0.50, about 1:0.25 to 1:0.45, or about 1:0.30 to 1:0.40. In the mixed gas of methane, carbon dioxide, and water vapor, the molar ratio of methane, carbon dioxide, and water vapor is about 1:0.20 to 0.50:0.01 to 1.45, about 1:0.25 to 0.45:0.10 to 1.35, or about 1:0.30 to 0.40:0.50 to 1.0.

[0159] The carbon source gas is, for example, carbon monoxide or carbon dioxide. The carbon source gas is, for example, a mixture of methane and nitrogen. In the mixture of methane and nitrogen, the molar ratio of methane to nitrogen is about 1:0.20 to 1:0.50, about 1:0.25 to 1:0.45, and about 1:0.30 to 1:0.40. The carbon source gas may not contain an inert gas such as nitrogen.

[0160] The heat treatment pressure can be selected by considering the heat treatment temperature, the composition of the gas mixture, and the desired amount of carbon coating. The heat treatment pressure can be controlled by adjusting the amount of the incoming gas mixture and the amount of the outgoing gas mixture. The heat treatment pressure is, for example, 0.5 atm or more, 1 atm or more, 2 atm or more, 3 atm or more, 4 atm or more, or 5 atm or more.

[0161] The heat treatment time is not specifically limited and can be appropriately adjusted according to the heat treatment temperature, pressure during heat treatment, composition of the gas mixture, and the desired amount of carbon coating. For example, the reaction time at the heat treatment temperature is, for example, 10 minutes to 100 hours, 30 minutes to 90 hours, or 50 minutes to 40 hours. For example, as the heat treatment time increases, the amount of deposited carbon, for example, graphene (carbon), increases, and accordingly, the electrical properties of the composite may be improved. However, this trend may not necessarily be directly proportional to time. For example, after a predetermined period of time, carbon deposition, for example, graphene deposition, may no longer occur or the deposition rate may decrease.

[0162] Through the gas phase reaction of the aforementioned carbon source gas, M even at a relatively low temperature a O c (0 <a≤3, 0<c≤4, a가 1, 2, 또는 3이면, c는 정수임)로 표시되는 제2 금속산화물 및 그 환원 생성물인 M a O b (0 <a≤3, 0<b<4, a는 1, 2, 또는 3이며, b 는 정수가 아님)로 표시되는 제1 금속산화물 중에서 선택된 하나 이상에 균일한 탄소계 재료의 코팅 예를 들어 그래핀 코팅을 제공함에 의하여 미도핑 복합체가 얻어진다.

[0163] The undoped composite comprises, for example, a matrix of a carbon-based material having one or more structures selected from a spherical structure, a spiral structure in which multiple spherical structures are connected, a cluster structure in which multiple spherical structures are aggregated, and a sponge structure, for example, a graphene matrix, and M disposed within the matrix of the carbon-based material. a O b (0 <a≤3, 0<b<4, a는 1, 2, 또는 3이며, b 는 정수가 아님)로 표시되는 제1 금속산화물 및 M a O c (0 <a≤3, 0<c≤4, a가 1, 2, 또는 3이면, c는 정수임)로 표시되는 제2 금속산화물 중에서 선택된 하나 이상을 포함한다.

[0164] Next, a fluorine (F)-doped complex is prepared by contacting an undoped complex with a fluorine (F)-containing compound.

[0165] For example, a solution can be prepared by mixing an undoped complex and a fluorine (F)-containing compound under a solvent, allowing it to stand for a certain period of time, then removing the solvent, washing, and drying to prepare a fluorine (F)-doped complex. In the solution containing the undoped complex and the fluorine (F)-containing compound, the fluorine (F) element contained in the fluorine (F)-containing compound is doped into the complex through a chemical reaction.

[0166] The solvent is not particularly limited and any solvent capable of dissolving the fluorine (F)-containing compound and dispersing the undoped complex is acceptable. The solvent is, for example, an organic solvent. The solvent is, for example, an aprotic solvent. The solvent is, for example, acetonitrile. The time for which the solution is left standing is not particularly limited as long as the time for which the undoped complex and the fluorine (F)-containing compound can react to dope the complex with fluorine (F). The standing time may be, for example, 1 day to 10 weeks, 1 week to 5 weeks, 2 weeks to 5 weeks, or 3 weeks to 5 weeks. The temperature at which the solution is left standing is not particularly limited as long as the temperature at which the undoped complex and the fluorine (F)-containing compound can react to dope the complex with fluorine (F). The temperature at which the solution is left standing may be, for example, 10 to 50°C, or 20 to 30°C.

[0167] Alternatively, a fluorine (F)-doped complex can be prepared by contacting an undoped complex with a gaseous fluorine (F)-containing compound.

[0168] Fluorine (F)-containing compounds are not particularly limited as long as they contain fluorine (F) atoms, and may be fluorine (F)-containing organic compounds or fluorine (F)-containing inorganic compounds. Fluorine (F)-containing compounds may be, for example, fluorination agents.

[0169] Fluorine (F)-containing compounds include, for example, chemical species in liquid, gaseous, or plasma states containing F.

[0170] Fluorine (F) containing compounds are selected from, for example, hydrogen fluoride (HF), [NO2]BF4 (nitronium tetraborate), [Et2NSF2]BF4 (Diethylamino)difluorosulfonium tetrafluoroborate), HPF6, XeF2, F2 gas, F2 / Ar plasma, CF4 plasma, SF6 plasma, or combinations thereof.

[0171] Next, the lithium transition metal oxide and the composite are mechanically milled. A Novilta mixer or the like may be used during milling. The rotational speed of the mixer during milling is, for example, 1,000 rpm to 2,500 rpm. If the milling speed is less than 1,000 rpm, the shear force applied to the lithium transition metal oxide and the composite is weak, making it difficult for the lithium transition metal oxide and the composite to form chemical bonds. If the milling speed is excessively high, the composite formation proceeds in an excessively short time, which may result in the composite being uniformly coated on the lithium transition metal oxide, making it difficult to form a uniform and continuous shell. The milling time is, for example, 5 to 100 minutes, 5 to 60 minutes, or 5 to 30 minutes. If the milling time is excessively short, the composite may be uniformly coated on the lithium transition metal oxide, making it difficult to form a uniform and continuous shell. If the milling time is excessively long, production efficiency may decrease. The content of the composite may be 3 wt% or less, 2 wt% or less, or 1 wt% or less of the total weight of the lithium transition metal oxide and the composite. For example, the content of the composite may be 0.01 to 3 wt%, 0.1 to 2 wt%, or 0.1 to 1 wt% of the total weight of the lithium transition metal oxide and the composite. For example, with respect to 100 parts by weight of the mixture of the lithium transition metal oxide and the composite, the content of the composite may be 0.01 to 3 parts by weight, 0.1 to 3 parts by weight, 0.1 to 2 parts by weight, or 0.1 to 1 part by weight.

[0172] The average particle size (D50) of the composite used for mechanical milling of the lithium transition metal oxide and the composite is, for example, 1 µm to 20 µm, 3 µm to 15 µm, or 5 µm to 10 µm.

[0173] The present invention is explained in more detail through the following examples and comparative examples. However, the examples are intended to illustrate the present invention and do not limit the scope of the present invention.

[0174] (Manufacturing of complexes)

[0175] Reference Preparation Example 1: Undoped Al 2 O 3 @Gr complex

[0176] Al2O3 particles (average particle size: about 20 nm) were placed in the reactor, and then CH4 was supplied into the reactor at about 300 sccm at 1 atm for about 30 minutes, and the internal temperature of the reactor was raised to 1000℃.

[0177] Subsequently, heat treatment was performed by maintaining the above temperature for 7 hours. Then, the internal temperature of the reactor was adjusted to room temperature (20-25℃) to [treat] the Al2O3 particles and their reduction product, Al2O3 z (0 <z<3) 입자가 그래핀에 매립된 미도핑 복합체를 얻었다.

[0178] The alumina content of the undoped complex was 60 wt%.

[0179] Preparation Example 1: Fluorine (F)-doped Al 2 O 3 @Gr complex

[0180] 2.8 g of NO2BF4 (nitronium tetrafluoroborate) was dissolved in 100 ml of acetonitrile, and then 0.13 g of the complex obtained in Reference Preparation Example 1 was dispersed in the mixture to prepare a dispersion. After leaving the prepared dispersion at room temperature for 4 weeks, the complex was separated, washed with acetonitrile, filtered, and dried. Fluorine (P) is doped into the complex through the reaction between NO2BF4 and the complex.

[0181] (Manufacturing of composite cathode active material)

[0182] Example 1: Fluorine (F) Doped Al 2 O 3 @Gr Composite 0.4 wt% (Alumina 0.24 wt%) Coated NCA91

[0183] LiNi 0.91 Co 0.05 Al 0.04A composite cathode active material was obtained by milling O2 (hereinafter referred to as NCA91) and the composite prepared in Preparation Example 1 at a rotational speed of about 1000 to 2000 rpm for about 5 to 30 minutes using a Nobilta Mixer (Nobilta Mixer, Hosokawa, Japan).

[0184] The mixing weight ratio of NCA and the composite obtained according to Preparation Example 1 was 99.6:0.4.

[0185] Example 2: Fluorine (F) Doped Al 2 O 3 @Gr Complex 0.25 wt% Coated NCA91

[0186] A composite cathode active material was prepared in the same manner as in Example 1, except that the mixing weight ratio of NCA91 and the composite obtained according to Preparation Example 1 was changed to 99.75:0.25.

[0187] Example 3: Fluorine (F) Doped Al 2 O 3 @Gr Complex 0.1 wt% Coated NCA91

[0188] A composite cathode active material was prepared in the same manner as in Example 1, except that the mixing weight ratio of NCA91 and the composite obtained according to Preparation Example 1 was changed to 99.9:0.1.

[0189] Example 4: Fluorine (F) Doped Al 2 O 3 @Gr Composite 1.0 wt% Coating NCA91

[0190] A composite cathode active material was prepared in the same manner as in Example 1, except that the mixing weight ratio of NCA91 and the composite obtained according to Preparation Example 1 was changed to 99.0:1.0.

[0191] Comparative Example 1: bare NCA91

[0192] NCA91 was used as is as the positive active material.

[0193] Reference Example 1: Undoped Al 2 O 3 @Gr Complex 0.4 wt% Coated NCA91

[0194] A composite cathode active material was prepared in the same manner as in Example 1, except that the undoped Al2O3@Gr composite prepared in Reference Example 1 was used instead of the fluorine (F) doped Al2O3@Gr composite prepared in Preparation Example 1.

[0195] (Manufacturing of lithium batteries (half cells))

[0196] Example 5

[0197] (Manufacturing of the anode)

[0198] A mixture of the composite cathode active material prepared in Example 1, a carbon conductive agent (Denka Black), and polyvinylidene fluoride (PVdF) in a weight ratio of 96:2:2 was mixed with N-methylpyrrolidone (NMP) in a mortar to prepare a slurry.

[0199] The above slurry was bar-coated onto a 15㎛ thick aluminum current collector, dried at room temperature, dried once more under vacuum conditions at 120℃, and then rolled and punched to produce an anode plate with a thickness of 55㎛.

[0200] Electrode loading level 10.5 mg / cm² 2 It was, and the density of the electrode mixture was 3.6 g / cc.

[0201] (Manufacturing of coin cells)

[0202] Coin cells were each manufactured using the anode plate prepared above, with lithium metal as the counter electrode, a PTFE separator, and a solution in which 1.15 M LiPF6 and 1.5 wt% vinylene carbonate (VC) were dissolved in EC (ethylene carbonate) + EMC (ethyl methyl carbonate) + DMC (dimethyl carbonate) (2:4:4 volume ratio) as the electrolyte.

[0203] Examples 6 to 8

[0204] A coin cell was manufactured in the same manner as in Example 5, except that the composite cathode active material prepared in Examples 2 to 4 was used instead of the composite cathode active material prepared in Example 1.

[0205] Comparative Example 2

[0206] Coin cells were manufactured in the same manner as in Example 5, except that the composite cathode active material prepared in Comparative Example 1 was used instead of the composite cathode active material prepared in Example 1.

[0207] Reference Example 2

[0208] Coin cells were manufactured in the same manner as in Example 5, except that the composite cathode active material prepared in Reference Example 1 was used instead of the composite cathode active material prepared in Example 1.

[0209] Evaluation Example 1: XPS Spectrum Evaluation

[0210] XPS spectra were measured using a Qunatum 2000 (Physical Electronics) over time during the preparation process of the undoped composite prepared in Reference Preparation Example 1. XPS spectra of C 1s orbitals and Al 2p orbitals were measured for samples before heating, after 1 minute, after 5 minutes, after 30 minutes, after 1 hour, and after 4 hours, respectively. At the beginning of heating, only the peak for Al 2p orbitals appeared, and no peak for C 1s orbitals appeared. After 30 minutes, the peak for C 1s orbitals appeared clearly, and the size of the peak for Al 2p orbitals decreased significantly.

[0211] After 30 minutes, peaks for C 1s orbitals attributed to CC bonds and C=C bonds due to graphene growth appeared clearly near 284.5 eV.

[0212] As the oxidation number of aluminum decreased over time, the peak position of the Al 2p orbital shifted toward a lower binding energy (eV).

[0213] Therefore, as the reaction proceeds, graphene grows on the Al2O3 particles, and Al2O3, which is the reduction product of Al2O3 x (0 <x<3)가 생성됨을 확인하였다.

[0214] The average content of carbon and aluminum was measured through XPS analysis results in 10 regions of the composite sample prepared in Reference Preparation Example 1. The deviation of the aluminum content for each region was calculated based on the measurement results. The deviation of the aluminum content was expressed as a percentage of the average value and referred to as uniformity. The percentage of the deviation of the aluminum content relative to the average value, i.e., the uniformity of the aluminum content, was 1%. Therefore, it was confirmed that alumina is uniformly distributed within the composite prepared in Reference Preparation Example 1.

[0215] Evaluation Example 2: XPS Spectrum Evaluation

[0216] The XPS spectra of the undoped composite prepared in Reference Preparation Example 1 and the doped composite prepared in Preparation Example 1 are respectively shown in Figure 1.

[0217] As shown in Fig. 1, the doped composite prepared in Preparation Example 1 additionally exhibited peaks for the fluorine (F) element, the nitrogen (N) element, and the boron (B) element.

[0218] Therefore, it was confirmed that the doped complex prepared in Preparation Example 1 was doped with the fluorine (F) element.

[0219] In contrast, the undoped composite prepared in Reference Preparation Example 1 did not show peaks for the fluorine (F) element, the nitrogen (N) element, and the boron (B) element.

[0220] The content of elements obtained from the XPS spectra of the undoped composite prepared in Reference Preparation Example 1 and the doped composite prepared in Preparation Example 1 is shown in Table 1 below.

[0221] Reference Preparation Example 1 [at%] Preparation Example 1 [at%] C 1s 82.4 74.4 O 1s 9.7 9.4 Al 2p 7.9 4.9 N 1s - 6.1 F 1s - 4.2 B 1s - 0.8

[0222] As shown in Table 1, the undoped composite prepared in Reference Preparation Example 1 did not contain the elements fluorine (P), nitrogen (N), and boron (B).

[0223] In contrast, the elemental fluorine (F) content of the fluorine (F) doping complex prepared in Preparation Example 1 was 4.2 at%.

[0224] Evaluation Example 3: SEM, HR-TEM, and SEM-EDAX Analysis

[0225] Scanning electron microscopy, high-resolution transmission electron microscopy, and EDAX analysis were performed on the undoped composite prepared in Reference Preparation Example 1, the fluorine (F) doped composite prepared in Preparation Example 1, the composite cathode active material prepared in Example 1, and the bare NCA of Comparative Example 1.

[0226] Philips' FEI Titan 80-300 was used for SEM-EDAX analysis.

[0227] The undoped composite prepared in Reference Preparation Example 1 consists of Al2O3 particles and their reduction product, Al2O z (0 <z<3) 입자가 그래핀에 매립된 구조를 가짐을 보여주었다. Al2O3입자 및 Al2O z (0 <z<3) 중에서 선택된 하나 이상의 입자의 외곽에 그래핀층이 배치됨을 확인하였다. Al2O3입자 및 Al2O z (0 <z<3) 중에서 선택된 하나 이상의 입자는 그래핀 메트릭스 내에 균일하게 분산되었다. Al2O3입자 및 Al2O z(0 <z<3) 입자 중 하나 이상의 입경은 약 20nm 이었다. 참고 제조예 1에서 제조된 미도핑 복합체의 입경은 약 100nm 내지 200nm 이었다. 제조예 1에서 제조된 불소(F) 도핑 복합체도 참고 제조예 1에서 제조된 복합체와 유사한 구조 및 입경을 나타내었다.

[0228] It was confirmed that in the composite cathode active material prepared in Example 1, a shell formed by a composite containing fluorine (F) doped graphene is disposed on the NCA core.

[0229] SEM-EDAX analysis was performed on the bare NCA of Comparative Example 1 and the composite cathode active material prepared in Example 1.

[0230] It was confirmed that the concentration of aluminum (Al) distributed on the surface of the composite cathode active material of Example 1 increased compared to the surface of the bare NCA composite cathode active material of Comparative Example 1.

[0231] Therefore, it was confirmed that the fluorine (F) doping composite prepared in Preparation Example 1 is uniformly coated on the NCA core of the composite cathode active material of Example 1 to form a shell.

[0232] Evaluation Example 4: Evaluation of Room Temperature (25℃) Charge / Discharge Characteristics

[0233] The lithium batteries prepared in Examples 5 to 8, Comparative Example 2, and Reference Example 2 were charged at a constant current rate of 0.1C at 25°C until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, they were discharged at a constant current rate of 0.1C until the voltage reached 2.8V (vs. Li) during discharge (formation cycle).

[0234] The lithium battery, having undergone a formation cycle, was charged at a constant current rate of 0.2C at 25°C until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, it was discharged at a constant current rate of 0.2C until the voltage reached 2.8V (vs. Li) during discharge (1 st Cycle). 50 of these cycles th The process was repeated under the same conditions up to the cycle (50 repetitions).

[0235] In all charge / discharge cycles, a 10-minute pause was observed after each charge / discharge cycle. Part of the results of the room temperature charge / discharge experiments are shown in Table 2 below. The initial efficiency is defined by Equation 1 below, and the capacity retention rate is defined by Equation 2 below.

[0236] <Mathematical Formula 1>

[0237] Initial efficiency[%] = [Discharge capacity in chemistry cycle / Charge capacity in chemistry cycle] × 100

[0238] <Mathematical Formula 2>

[0239] Capacity retention rate[%] = [50 th Discharge capacity per cycle / 1 st [Discharge capacity per cycle] × 100

[0240] Initial efficiency[%] Capacity retention rate[%] Example 5: 0.4 wt% Fluorine (F) Doped Al2O3@Gr Composite Coating / NCA91 Core 90.4 91.8 Comparative Example 2: Bare NCA91 (no coating) 90.3 91.2 Reference Example 2: 0.4wt% coating of undoped Al2O3@Gr complex / NCA91 core 90.5 91.2

[0241] As shown in Table 2, the lithium battery of Example 5 had improved initial efficiency compared to the lithium battery of Comparative Example 2.

[0242] The lithium batteries of Examples 5 to 8 showed improved room temperature life characteristics compared to the lithium battery of Comparative Example 2.

[0243] Evaluation Example 5: Evaluation of Room Temperature High Rate Characteristics

[0244] The lithium batteries prepared in Examples 5 to 8, Comparative Example 2, and Reference Example 2 were charged at a constant current rate of 0.1C at 25°C until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, they were discharged at a constant current rate of 0.1C until the voltage reached 2.8V (vs. Li) during discharge (formation cycle).

[0245] The lithium battery, having undergone a formation cycle, was charged at a constant current rate of 0.2C at 25°C until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, it was discharged at a constant current rate of 0.2C until the voltage reached 2.8V (vs. Li) during discharge (1 st Cycle).

[0246] The lithium battery, having undergone the first cycle, was charged at a constant current rate of 0.2C at 25℃ until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, it was discharged at a constant current rate of 0.5C until the voltage reached 2.8V (vs. Li) during discharge (2 nd Cycle).

[0247] 2 nd The cycled lithium battery was charged at a constant current rate of 0.2C at 25℃ until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, it was discharged at a constant current rate of 1.0C until the voltage reached 2.8V (vs. Li) during discharge (3 rd Cycle).

[0248] 3 rdThe cycled lithium battery was charged at a constant current rate of 0.2C at 25℃ until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, it was discharged at a constant current rate of 2.0C until the voltage reached 2.8V (vs. Li) during discharge (4 st Cycle).

[0249] 4 th The cycled lithium battery was charged at a constant current rate of 0.2C at 25℃ until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, it was discharged at a constant current rate of 4.0C until the voltage reached 2.8V (vs. Li) during discharge (5 st Cycle).

[0250] In all charge / discharge cycles, a 10-minute pause was observed after each charge / discharge cycle. Some of the results of the room temperature charge / discharge experiments are shown in Table 3 below. The high-rate characteristic is defined by Equation 3 below.

[0251] <Mathematical Formula 3>

[0252] High rate characteristics[%] = [4.0 C rate discharge capacity (5 th Cycle discharge capacity) / 0.2C rate discharge capacity(1 st Cycle discharge capacity)] × 100

[0253] 0.2 C discharge capacity (1 st Cycle)[mAh / g] 4.0 C discharge capacity (5 st Cycle)[mAh / g] High rate characteristics[%] Example 5: 0.4 wt% Fluorine (F) Doped Al2O3@Gr Composite Coating / NCA91 Core 208.4 191.3 95.6 Comparative Example 2: Bare NCA91 (no coating) 209.4 190.9 94.8 Reference Example 2: 0.4wt% coating of undoped Al2O3@Gr complex / NCA91 core 209.1 190.7 95.4

[0254] As shown in Table 3, the lithium battery of Example 5 showed improved high-rate characteristics compared to the lithium battery of Comparative Example 2.

[0255] Evaluation Example 6: Evaluation of High Temperature (45℃) Charge / Discharge Characteristics

[0256] The lithium batteries prepared in Examples 5 to 8, Comparative Example 2, and Reference Example 2 were charged at a constant current rate of 0.2C at 25°C until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, they were discharged at a constant current rate of 0.2C until the voltage reached 2.8V (vs. Li) during discharge (formation cycle).

[0257] The lithium battery, having undergone a formation cycle, was charged at a constant current rate of 0.2C at 45°C until the voltage reached 4.4V (vs. Li), and then cut off at a current rate of 0.05C while maintaining 4.4V in constant voltage mode. Subsequently, it was discharged at a constant current rate of 0.2C until the voltage reached 2.8V (vs. Li) during discharge (1 st Cycle). 100 of these cycles th The process was repeated under the same conditions up to the cycle (repeated 100 times).

[0258] In all charge / discharge cycles, a 10-minute pause was observed after each charge / discharge cycle. Some of the results of the high-temperature charge / discharge experiments are shown in Table 4 below. The initial efficiency is defined by Equation 4 below, and the capacity retention rate is defined by Equation 5 below.

[0259] <Mathematical Formula 4>

[0260] Charge / Discharge Efficiency [%] = [Discharge Capacity in Formation Cycle / Charge Capacity in Formation Cycle] × 100

[0261] <Mathematical Formula 5>

[0262] Capacity retention rate[%] = [100 th Discharge capacity per cycle / 1 st [Discharge capacity per cycle] × 100

[0263] Charge / Discharge Efficiency[%] High temperature capacity retention rate [%] Example 5: 0.4 wt% Fluorine (F) Doped Al2O3@Gr Composite Coating / NCA91 Core 88.6 81.3 Example 6: 0.25 wt% Fluorine (F) Doped Al2O3@Gr Composite Coating / NCA91 Core 88.2 74.6 Example 7: 0.1 wt% Fluorine (F) Doped Al2O3@Gr Composite Coating / NCA91 Core 88.2 69.8 Example 8: 1.0 wt% Fluorine (F) Doped Al2O3@Gr Composite Coating / NCA91 Core 88.4 80.1 Comparative Example 2: Bare NCA91 (no coating) 88.0 63.4 Reference Example 2: 0.4wt% coating of undoped Al2O3@Gr complex / NCA91 core 88.4 79.3

[0264] As shown in Table 4, the lithium batteries of Examples 5 to 8 had improved initial efficiency compared to the lithium battery of Comparative Example 2.

[0265] The lithium batteries of Examples 5 to 8 showed significantly improved high-temperature life characteristics compared to the lithium battery of Comparative Example 2.

[0266] Evaluation Example 7: Electrode Conductivity Evaluation

[0267] The conductivity of the anodes prepared in Example 5, Comparative Example 2, and Reference Example 2 was measured.

[0268] The conductivity of the anode was measured using a HIOKI XF057 PROBE UNIT. For the anodes prepared in Example 5, Comparative Example 2, and Reference Example 2, specimens were prepared by punching a circular shape with a diameter of Φ36 (36 mm), and the thickness of the electrode plate was measured to calculate the thickness of the electrode active material layer. A probe was placed on the electrode active material layer, the resistance of the anode was measured, and the conductivity of the anode was calculated from this.

[0269] The measurement results are shown in Table 5 below.

[0270] Conductivity [S / m] Example 5: 0.4 wt% Fluorine (F) Doped Al2O3@Gr Composite Coating / NCA91 Core 13.1 Comparative Example 2: Bare NCA91 (no coating) 11.4 Reference Example 2: 0.4wt% coating of undoped Al2O3@Gr complex / NCA91 core 10.6

[0271] As shown in Table 5, the electrode conductivity of the lithium battery of Reference Example 2 was reduced compared to the lithium battery of Comparative Example 2 without a shell by introducing a shell.

[0272] In contrast, the lithium battery of Example 5 had significantly improved electrode conductivity compared to the lithium battery of Comparative Example 2 due to the doping of fluorine into the shell.

Claims

Claim 1 A core comprising a lithium transition metal oxide; and a shell disposed along the surface of the core; wherein the shell is of the formula M a O b (0 <a≤3, 0<b<4, a가 1, 2, 또는 3 이면, b는 정수가 아님)로 표시되는 1종 이상의 제1 금속산화물; 탄소계 재료; 및 도핑된 불소(F) 원소를 포함하며,상기 제1 금속산화물이 탄소계 재료 메트릭스 내에 배치되며, 상기 M은 원소주기율표 2족 내지 13족, 제15족 및 16족 중에서 선택된 하나 이상의 금속이며,상기 제1 금속산화물이 Al2O z (0 <z<3), NbO x (0 <x<2.5), MgO x (0 <x<1), Sc2O z (0 <z<3), TiO y (0 <y<2), ZrO y (0 <y<2), V2O z (0 <z<3), WO y (0 <y<2), MnO y (0 <y<2), Fe2O z (0 <z<3), Co3O w (0 <w<4), PdO x (0 <x<1), CuO x (0 <x<1), AgO x (0 <x<1), ZnO x (0 <x<1), Sb2O z (0 <z<3), 및SeO y (0 <y<2) 중에서 선택되는 하나 이상인, 복합양극활물질. Claim 2 A composite cathode active material according to claim 1, wherein the doped fluorine (F) content contained in the shell is 1 to 10 at% relative to the total number of atoms of the shell. Claim 3 A composite cathode active material according to claim 1, wherein the content of the first metal included in the shell is 1 to 10 at% relative to the total number of atoms of the shell, the oxygen content included in the shell is 1 to 20 at% relative to the total number of atoms of the shell, the nitrogen content included in the shell is 1 to 12 at% relative to the total number of atoms of the shell, and the boron content included in the shell is greater than 0 to 5 at% relative to the total number of atoms of the shell. Claim 4 A composite cathode active material according to claim 1, wherein the carbon content of the shell is 65 to 99 at% relative to the total number of atoms of the shell. Claim 5 delete Claim 6 delete Claim 7 A composite cathode active material according to claim 1, wherein the thickness of the shell is 1 nm to 5 µm. Claim 8 In claim 1, the carbon-based material is a composite cathode active material in which graphene is used. Claim 9 A composite cathode active material according to claim 1, wherein the shell comprises one or more selected from a composite comprising the first metal oxide and a carbon-based material and a doped fluorine (F) element and a milling result of the composite, and the content of one or more selected from the composite and the milling result of the composite is 3 wt% or less of the total weight of the composite cathode active material. Claim 10 A composite cathode active material according to claim 9, wherein the carbon-based material has a branched structure, the metal oxide is distributed within the branched structure, and the branched structure comprises a plurality of carbon-based material particles in contact with each other. Claim 11 A composite cathode active material according to claim 9, wherein the carbon-based material has one or more structures selected from a spherical structure, a spiral structure in which the spherical structures are connected, and a cluster structure in which the spherical structures are aggregated, the first metal oxide is distributed within the spherical structure, the size of the spherical structure is 50 nm to 300 nm, the size of the spiral structure is 500 nm to 100 µm, and the size of the cluster structure is 0.5 mm to 10 cm, the composite is a faceted-ball structure or a planar structure, and one or more selected from the first metal oxide and the second metal oxide are distributed inside or on the surface of the structure, the carbon-based material extends by a distance of 10 nm or less from the first metal oxide, comprises at least 1 to 20 layers of carbon-based material, and the total thickness of the carbon-based material is 0.6 to 12 nm. Claim 12 In claim 1, the lithium transition metal oxide is a composite cathode active material represented by the following chemical formulas 1 to 5: <Chemical Formula 1>Li a Ni x Co y M z O 2-b A b In the above chemical formula 1, 1.0≤a≤1.2, 0≤b≤0.2, 0.8≤x<1, 0 <y≤0.3, 0<z≤0.3, 및 x+y+z=1이고,M은 망간(Mn), 니오븀(Nb), 바나듐(V), 마그네슘(Mg), 갈륨(Ga), 실리콘(Si), 텅스텐(W), 몰리브덴(Mo), 철(Fe), 크롬(Cr), 구리(Cu), 아연(Zn), 티타늄(Ti), 알루미늄(Al) 또는 이들의 조합이고,A는 F, S, Cl, Br 또는 이들의 조합이며,<화학식 2> LiNi x Co y Mn z O2<Chemical Formula 3>LiNi x Co y Al z O2 In the above chemical formulas 2 to 3, 0.8≤x≤0.95, 0 <y≤0.2, 0<z≤0.2 및 x+y+z=1이며,<화학식 4> LiNi x Co y Mn v Al w O2 In the above chemical formula 4, 0.8≤x≤0.95, 0 <y≤0.2, 0<v≤0.2, 0<w≤0.2, 및 x+y+v+w=1이며,<화학식 5> Li a Co x M y O 2-b A b In the above chemical formula 5, 1.0≤a≤1.2, 0≤b≤0.2, 0.9≤x≤1, 0≤y≤0.1, and x+y=1, M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al) or a combination thereof, and A is F, S, Cl, Br or a combination thereof. Claim 13 A cathode comprising a composite cathode active material according to any one of claims 1 to 4 and claims 7 to 12. Claim 14 A lithium battery comprising a positive electrode of claim 13; a negative electrode; and an electrolyte disposed between the positive electrode and the negative electrode. Claim 15 The method comprises the steps of: providing a lithium transition metal oxide; providing a complex; and mechanically milling the lithium transition metal oxide and the complex, wherein the complex is of the formula M a O b (0 <a≤3, 0<b<4, a가 1, 2, 또는 3 이면, b는 정수가 아님)로 표시되는 1종 이상의 제1 금속산화물; 탄소계 재료; 및 도핑된 불소(F) 원소를 포함하며,상기 제1 금속산화물이 탄소계 재료 메트릭스 내에 배치되며, 상기 M은 원소주기율표 2족 내지 13족, 제15족 및 16족 중에서 선택된 하나 이상의 금속이며,상기 제1 금속산화물이 Al2O z (0 <z<3), NbO x (0 <x<2.5), MgO x (0 <x<1), Sc2O z (0 <z<3), TiO y (0 <y<2), ZrO y (0 <y<2), V2O z (0 <z<3), WO y (0 <y<2), MnO y (0 <y<2), Fe2O z (0 <z<3), Co3O w (0 <w<4), PdO x (0 <x<1), CuO x (0 <x<1), AgO x (0 <x<1), ZnO x (0 <x<1), Sb2O z (0 <z<3), 및SeO y (0 <y<2) 중에서 선택되는 하나 이상인, 복합양극활물질 제조방법. Claim 16 In claim 15, the step of providing the above composite is, M a O c (0 <a≤3, 0<c≤4, a가 1, 2, 또는 3 이면, c는 정수임)로 표시되는 1종 이상의 제2 금속산화물에 탄소 공급원 기체로 이루어진 반응 가스를 공급하고 열처리하여 미도핑(undoped) 복합체를 제공하는 단계; 및미도핑 복합체와 불소(F) 함유 화합물을 접촉시켜 복합체를 준비하는 단계를 포함하며,상기 M은 원소주기율표 2족 내지 13족, 제15족 및 16족 중에서 선택된 하나 이상의 금속인, 복합양극활물질 제조방법. Claim 17 A method for manufacturing a composite cathode active material according to claim 16, wherein the fluorine (F) containing compound is one or more selected from hydrogen fluoride (HF), [NO2]BF4 (nitronium tetraborate), [Et2NSF2]BF4 (Diethylamino)difluorosulfonium tetrafluoroborate), HPF6, XeF2, F2 gas, F2 / Ar plasma, CF4 plasma, and SF6 plasma.

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