Positive electrode active material, secondary battery, and method for producing positive electrode active material

Abstract

To provide a positive electrode active material capable of simultaneously improving the capacity and life of a battery.SOLUTION: A positive electrode active material comprising: particles comprising a compound represented by the following Chemical Formula 1; and an outer layer surrounding the particles, wherein a I003 / I104 value of the positive electrode active material is in a range of 0.8 to 1.2, a (I102 + I006) / (I101) value of the positive electrode active material is in a range of 0.448 to 0.467, and a c-axis length of the positive electrode active material is in a range of 14.1870 Å to 14.1893 Å. Lia [(NixMnyCozM1w)] O2 In Chemical Formula 1, 0.9 ≤ a ≤ 1.1, 0.8 ≤ x <1.0, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 0.5, 0 <w <0.005, and x + y + z + w = 1, and M1 includes one or more selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention claims the benefit of the priority date of Patent Application No. 10-2024-0083611, filed with the Korean Intellectual Property Office on June 26, 2024, the entire contents of which are incorporated herein by reference. The present invention relates to a positive electrode active material. The present invention relates to a secondary battery. The present invention relates to a method for producing a positive electrode active material. [Background technology]

[0002] Secondary batteries with high capacity and energy density are being developed. For these, a high Ni content LNCMO (lithium nickel-cobalt-manganese oxide)-based cathode active material can be used. However, as the Ni content of LNCMO increases, unstable Ni 3+ Ni is stable 2+ This can lead to cation mixing, which can result in reduced battery life. To solve this problem, methods of coating the positive electrode active material with various elements have been considered, but coating the positive electrode active material can reduce the battery capacity. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention provides a positive electrode active material that can simultaneously improve the capacity and life of a battery. The present invention seeks to provide a battery with simultaneously improved capacity and life. The present invention provides a method for producing a positive electrode active material that can simultaneously improve the capacity and life of a battery. [Means for solving the problem]

[0004] One embodiment of the present invention is a positive electrode active material comprising particles containing a compound represented by the following chemical formula 1; and an outer shell layer surrounding the particles, wherein the I003 / I104 value of the positive electrode active material is within the range of 0.8 to 1.2, the (I102 + I006) / (I101) value of the positive electrode active material is within the range of 0.448 to 0.467, and the length of the c-axis of the positive electrode active material is a positive electrode active material within the range of 14.1870 Å to 14.1893 Å. [Chemical formula 1] Li a [(Ni x Mn y Co z M1 w )]O2 In the chemical formula 1, 0.9 ≦ a ≦ 1.1, 0.8 ≦ x < 1.0, 0 ≦ y ≦ 0.5, 0 ≦ z ≦ 0.5, 0 < w < 0.005, and x + y + z + w = 1, and the M1 includes one or more selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W.

[0005] The outer shell layer includes an M2 component distributed on a part of the particle surface; and an M3 component different from the M2 component and distributed on the remaining part of the particle surface, the M2 component includes three or more selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W, and the M3 component may include one or more selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W.

[0006] The content of the M2 component may be greater than the content of the M3 component. The content of the M2 component may be within the range of 0.9 mol% to 1.8 mol%. The content of the M3 component may be within the range of 0.25 mol% to 0.35 mol%.

[0007] The M1 may include Zr. The M2 component may include Zr, Al, and Ti. The M3 component may include B.

[0008] Other embodiments of the present invention include a positive electrode, a negative electrode, and an electrolyte. The positive electrode includes a positive electrode active material. The positive electrode active material includes particles containing a compound represented by the following Chemical Formula 1; and an outer shell layer surrounding the particles. The I003 / I104 value of the positive electrode active material is within the range of 0.8 to 1.2, the (I102 + I006) / (I101) value of the positive electrode active material is within the range of 0.448 to 0.467, and the c-axis length of the positive electrode active material is within the range of 14.1870 Å to 14.1893 Å. It is a secondary battery: [Chemical Formula 1] Li a [(Ni x Mn y Co z M1 w )]O2 In Chemical Formula 1, 0.9 ≦ a ≦ 1.1, 0.8 ≦ x < 1.0, 0 ≦ y ≦ 0.5, 0 ≦ z ≦ 0.5, 0 < w < 0.005, and x + y + z + w = 1. The M1 includes one or more selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W.

[0009] Another embodiment of the present invention includes the steps of: preparing a hydroxide of a transition metal including nickel, cobalt, and manganese; calcining a first mixture including the transition metal hydroxide, an M1 component precursor, and a lithium compound to obtain a first lithium composite oxide; calcining a second mixture including the first lithium composite oxide and an M2 component precursor to obtain a second lithium composite oxide; washing the second lithium composite oxide with water; drying the washed second lithium composite oxide; and heat-treating a third mixture including the dried second lithium composite oxide and an M3 component precursor; wherein the M1 component is selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni , Ba, and W, the M2 component includes three or more components selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W, the M3 component includes at least one component selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W, and the M3 component is different from the M2 component, the content of the M3 component precursor in the third mixture is in the range of 0.25 mol to 0.35 mol per 100 mol of the dried second lithium composite oxide, and the heat-treating the third mixture is carried out at a temperature in the range of 250°C to 400°C.

[0010] The content of the M1 component precursor in the first mixture may be less than 0.5 moles per 100 moles of the transition metal hydroxide.

[0011] The content of the M2 component precursor in the second mixture may be within a range of 0.9 mol to 1.8 mol per 100 mol of the first lithium composite oxide.

[0012] The M1 component may include Zr, the M2 component may include Zr, Al and Ti, and the M3 component may include B. [Effects of the Invention]

[0013] The positive electrode active material of the present invention can improve both the capacity and the life of the battery. The batteries of the present invention can simultaneously have improved capacity and life. The method for producing a positive electrode active material of the present invention can produce a positive electrode active material that can simultaneously improve the capacity and life of a battery. [Brief explanation of the drawings]

[0014] [Figure 1] 1 shows the results of XRD analysis of Examples 2, 5, and 6 and Comparative Examples 1 and 4. [Figure 2] 1 shows the results of XRD analysis of Examples 1 to 4 and Comparative Examples 2 and 3. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will now be described in detail, but this description is given by way of example only, and the scope of the present invention is not limited to the specific examples described by way of example.

[0016] One embodiment of the present invention is a positive electrode active material. The positive electrode active material exhibits several properties when analyzed by X-ray diffraction (XRD) using CuKα radiation, and can improve the capacity and life characteristics of a battery including a positive electrode containing the positive electrode active material.

[0017] The positive electrode active material may have an I003 / I104 value in the range of 0.8 to 1.2, an (I102+I006) / (I101) value in the range of 0.448 to 0.467, and a c-axis length in the range of 14.1870 Å to 14.1893 Å. In addition, other properties of the positive electrode active material may be further adjusted, as described below.

[0018] In the present invention, as long as a certain numerical value is within the range of A to B, the numerical value may be A or more and B or less. In the present invention, some numerical values ​​may be rounded off.

[0019] The Iabc may refer to the integrated intensity of the diffraction peak of the (abc) plane in XRD analysis. The method for measuring this will be explained in more detail in the Examples section below.

[0020] The I003 / I104 value may represent the Ni occupancy of the positive electrode active material. The Ni occupancy may be one of the indicators of cation mixing. As the I003 / I104 value increases, the degree of cation mixing may decrease.

[0021] The I003 / I104 value of the positive electrode active material may be in the range of 0.8 to 1.2. If the value is less than 0.8, excessive cation mixing may occur. As a result, the battery life characteristics, especially high-temperature life characteristics, may be reduced. If the value is more than 1.2, excessive doping may occur in the positive electrode active material. As a result, the battery capacity may be reduced.

[0022] The value (I102+I006) / (I101) is also known as the R-Factor or hexagonal order.

[0023] Increasing or decreasing the R factor of the positive electrode active material can affect the hexagonal order, grain size, and layer structure of the positive electrode active material, and therefore the R factor can be appropriately adjusted.

[0024] The (I102 + I006) / (I101) value of the positive electrode active material may be within a range of 0.448 to 0.467. That is, in the present invention, the R factor of the positive electrode active material can be controlled very precisely. If the R factor is less than 0.448, the crystal grain size of the positive electrode active material may become large. As a result, both the capacity and life of the battery may decrease. If the R factor is more than 0.467, the layered structure of the positive electrode active material may become unstable. As a result, the capacity of the battery may decrease.

[0025] The c-axis length of the positive electrode active material can be related to the charge / discharge rate of the battery and the stability of the active material. The c-axis length of the positive electrode active material may refer to the c-axis length of the crystals contained in the positive electrode active material. The c-axis length of the positive electrode active material may be determined by XRD analysis of the positive electrode active material. A method for measuring the c-axis length of the positive electrode active material will be described in more detail in the Examples section below.

[0026] The c-axis length may be within a range of 14.1870 Å to 14.1893 Å. That is, the c-axis length of the positive electrode active material can be adjusted very precisely. If the c-axis length is less than 14.1870 Å, the charge / discharge rate of the battery may decrease. If the c-axis length is greater than 14.1893 Å, the stability of the active material may decrease.

[0027] The fact that the positive electrode active material satisfies all of the above characteristics means that the amorphous material is coated on the positive electrode active material under appropriate conditions. This also means that the performance of the positive electrode active material can be improved without significantly changing the crystalline structure of the positive electrode active material. As a result, the positive electrode active material that satisfies all of the above characteristics can simultaneously improve the capacity and life characteristics of a secondary battery.

[0028] The positive electrode active material may further satisfy additional properties. For example, the positive electrode active material may contain a specific element in a content within a specific range. Specifically, the B content of the positive electrode active material may be in the range of 0.135 wt % to 0.335 wt %. The B content of the positive electrode active material may be within a range of two of 0.135 wt %, 0.150 wt %, 0.200 wt %, 0.250 wt %, 0.300 wt %, and 0.335 wt %.

[0029] The B content can be measured based on the entire positive electrode active material, for example, by ICP analysis. The above-described properties of the positive electrode active material can be controlled by adjusting the structure and chemical composition of the positive electrode active material. The positive electrode active material may include particles and an outer layer surrounding the particles.

[0030] The particles may include LNMCO. Specifically, the composition of the LNMCO may be adjusted. More specifically, the particles may include a compound represented by the following Chemical Formula 1: [Chemical formula 1] Li a [(Ni x Mn y Co z M1 w )]O2 In the above formula 1, 0.9≦a≦1.1, 0.8≦x<1.0, 0≦y≦0.5, 0≦z≦0.5, 0 <w<0.005、およびx+y+z+w=1である。 In the above Chemical Formula 1, M1 may include at least one selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W. The a may represent the Ni and Li occupancy rate of the particle, and may be 1.0≦a≦1.1, or 1.0≦a≦1.05. The x may represent the Ni content of the particles, which may affect the capacity of the battery. The y may represent the Mn content of the particles, which may affect the safety of the battery. The z may refer to the Co content of the particles, which may affect the control of electrode corrosion and the risk of battery explosion.

[0031] When the contents of Ni, Mn, and Co in the LNMCO are appropriately adjusted, the capacity and life characteristics of the battery can be improved.

[0032] The M1 may refer to an element doped into the LNMCO. Specifically, the M1 may include Zr. When doped into the LNMCO, Zr is located at the Li site and may not participate in the battery reaction. The Zr can stabilize the lattice structure of the material when the battery is being charged.

[0033] The w may represent the content of the doping element. When the w value is greater than 0, the LNMCO can be doped into M1. When the w value is 0.5 or less, the capacity of the battery can be maintained.

[0034] The w value may be within the range of two of the following values: 0.1, 0.2, 0.3, 0.4 and 0.5. The sum of x, y, z, and w is 1.

[0035] The outer layer may include components that exhibit different compositions on the surface of the particle. Specifically, the outer layer may include an M2 component and an M3 component. The M2 component and the M3 component may be different from each other. The M2 component may include three or more components, and the M3 component may include one or more components.

[0036] Here, the M2 component can be distributed on a portion of the surface of the particle, and the M3 component can be distributed on the remaining portion of the surface of the particle, so that most of the surface of the particle can be surrounded by the M2 component and the M3 component.

[0037] The M2 component may contain three or more elements selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W. The types and content ratios of the three or more elements can be determined taking into consideration the oxidation number of each element, the crystal structure of the positive electrode active material, and the effect of the positive electrode active material on battery performance.

[0038] Specifically, the M2 component may include Zr, Al, and Ti. When the outer layer of the positive electrode active material contains Zr, the heat generated in the positive electrode can be easily dissipated to the outside due to the good thermal conductivity of Zr, and as a result, a battery including the positive electrode active material can exhibit good life characteristics.

[0039] When the outer layer of the positive electrode active material contains Al, the stability of the positive electrode can be improved. When the outer layer of the positive electrode active material contains Ti, it is possible to prevent physical contact between the positive electrode active material and the electrolyte, and also to prevent transition metals such as nickel, manganese, and cobalt from being eluted from the positive electrode active material.

[0040] The M3 component may contain one or more elements selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W. The M3 component may contain an element different from the M2 component.

[0041] Specifically, the M3 component may contain B. When the outer layer of the positive electrode active material contains B, the output characteristics and cycle characteristics of the battery can be improved. The content of the M2 component may be greater than the content of the M3 component. The contents of the M2 component and the M3 component may refer to the contents in the positive electrode active material.

[0042] The content of the M2 component may be within a range of 0.3 mol % to 0.6 mol % per component. The M2 component may contain three or more elements. Therefore, the content of the M2 component may be within a range of 0.9 mol % to 1.8 mol %.

[0043] The content of the M2 component may be within a range of two of 0.3 mol%, 0.4 mol%, 0.5 mol%, and 0.6 mol% per component, or within a range of two of 0.9 mol%, 1.0 mol%, 1.1 mol%, 1.2 mol%, 1.3 mol%, 1.4 mol%, 1.5 mol%, 1.6 mol%, 1.7 mol%, and 1.8 mol%.

[0044] The content of the M3 component may be within a range of 0.25 mol % to 0.35 mol %.

[0045] Another embodiment of the present invention is a secondary battery. The secondary battery may include a positive electrode, a negative electrode, and an electrolyte. Here, the electrolyte may include a separator and an electrolytic solution. The separator may be disposed between the positive electrode and the negative electrode. The positive electrode may be an electrode in which a reduction reaction occurs during discharge. The negative electrode may be an electrode in which an oxidation reaction occurs during discharge.

[0046] The battery electrode may include an electrode current collector and an electrode active material adhered to the electrode current collector. The positive electrode active material of the electrode active materials may include a lithium intercalation material. The positive electrode active material may be the positive electrode active material of the present invention.

[0047] The negative electrode active material may include a lithium adsorbent material, which may include at least one selected from the group consisting of lithium-based metals, including lithium metal and lithium alloys, and carbon-based compounds, including carbon, petroleum coke, activated carbon, and graphite.

[0048] The positive electrode current collector may be a foil of a metal containing at least one selected from the group consisting of aluminum and nickel. The negative electrode current collector may be a foil of a metal containing at least one selected from the group consisting of copper, gold, and nickel. The electrolyte may include an organic solvent and an ionic salt, the ionic salt being dissolved or dissociated in the organic solvent.

[0049] The organic solvent may include at least one selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), and gamma butyrolactone (γ-butyrolactone).

[0050] The ionic salt is A + B - may have the structure 。 In the above structure, A + Li + , Na + , and K. + In the above structure, B may contain an alkali metal cation such as - PF6 - , BF4 - , Cl - , Br - , I - , ClO4 - , AsF6 - , CH3CO2 - , CF3SO3 - , N(CF3SO2)2 - , and C(CF2SO2)3 - It may also contain anions such as

[0051] Another embodiment of the present invention is a method for producing a positive electrode active material. The manufacturing method of the present invention can manufacture a positive electrode active material having the above-mentioned properties.

[0052] The production method of the present invention may include at least the steps of: preparing a hydroxide of a transition metal containing nickel, cobalt, and manganese; calcining a first mixture containing the transition metal hydroxide, an M1 component precursor, and a lithium compound to obtain a first lithium composite oxide; calcining a second mixture containing the first lithium composite oxide and an M2 component precursor to obtain a second lithium composite oxide; washing the second lithium composite oxide with water; drying the washed second lithium composite oxide; and heat-treating a third mixture containing the dried second lithium composite oxide and an M3 component precursor.

[0053] The manufacturing method may include a step of preparing a transition metal hydroxide. The transition metal hydroxide may include nickel, cobalt, and manganese. That is, the transition metal of the transition metal hydroxide may include nickel, cobalt, and manganese.

[0054] The method may then include a step of calcining a first mixture containing the transition metal hydroxide, an M1 component precursor, and a lithium compound. The first mixture may be calcined to form a lithium transition metal oxide. The first mixture may further contain an M1 component precursor, and the lithium transition metal oxide may be doped with the M1 component. Calcining the first mixture may produce a first lithium composite oxide in which the M1 component is doped into the lithium transition metal oxide.

[0055] In the present invention, an M# component precursor can refer to any compound that allows an M# component to be detected in the resultant product after a given treatment, where # can be 1, 2, or 3.

[0056] The M# component may be the same as that described in the description of the positive electrode active material. The firing of the first mixture may be carried out in an oxygen atmosphere, thereby producing an oxide.

[0057] The method may then include a step of calcining a second mixture containing the first lithium composite oxide and an M2 component precursor. Calcining the second mixture can produce a second lithium composite oxide. The second lithium composite oxide may include the first lithium composite oxide and an M2 component formed on at least a portion of the surface of the first lithium composite oxide.

[0058] In the production method, the second lithium composite oxide may be washed with water and dried. Specifically, the production method may include the steps of washing the second lithium composite oxide with water and drying the washed second lithium composite oxide.

[0059] The method may further include heat-treating the washed and dried second lithium composite oxide. Specifically, the method may include heat-treating a third mixture containing the dried second lithium composite oxide and an M3 component precursor. As a result, a positive electrode active material satisfying the above-described properties (such as the above-described I003 / I104 value, (I102 + I006) / (I101) value, and c-axis length) can be produced.

[0060] In particular, the manufacturing method can produce a cathode active material that satisfies the above-mentioned characteristics by more precisely performing the heat treatment step of the third mixture. When the third mixture is heat-treated, the content of the M3 component precursor in the third mixture and the heat treatment temperature can be controlled.

[0061] Specifically, the content of the M3 component precursor in the third mixture may be within a range of 0.25 mol to 0.35 mol per 100 mol of the dried second lithium composite oxide. Furthermore, the heat treatment of the third mixture may be carried out within a range of 250°C to 400°C.

[0062] The content of the M3 component precursor in the third mixture may be within a range of two of 0.25 mol, 0.26 mol, 0.27 mol, 0.28 mol, 0.29 mol, 0.30 mol, 0.31 mol, 0.32 mol, 0.33 mol, 0.34 mol, and 0.35 mol, relative to 100 mol of the dried second lithium composite oxide.

[0063] The heat treatment temperature of the third mixture may be within a range of two of the following values: 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, and 400°C.

[0064] In the above manufacturing method, the composition and process conditions of each step can be more precisely controlled. The content of the M1 component precursor in the first mixture may be less than 0.5 mol per 100 mol of the transition metal hydroxide. As described above, the M1 component may refer to an element to be doped into the LNMCO, and the doping amount may be less than 0.5 mol per 100 mol of the transition metal hydroxide.

[0065] The content of the M1 component precursor in the first mixture may be within the range of two of 0.1 mol, 0.2 mol, 0.3 mol, 0.4 mol, and 0.5 mol per 100 mol of the transition metal hydroxide.

[0066] The first mixture may be fired in an oxygen atmosphere, thereby producing an oxide. The first mixture is fired at a temperature in the range of 600°C to 700°C. The firing temperature of the first mixture may be within the range of two of 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C and 700°C.

[0067] The firing of the first mixture may be carried out for a time period ranging from 10 hours to 14 hours. The baking time of the first mixture may be within the range of two of the following values: 10 hours, 11 hours, 12 hours, 13 hours, and 14 hours.

[0068] The content of the M2 component precursor in the second mixture may be within a range of 0.9 mol to 1.8 mol per 100 mol of the first lithium composite oxide. As described above, the M2 component contains three or more elements. Therefore, the content of each element constituting M3 in the second mixture may be within a range of 0.3 mol to 0.6 mol per 100 mol of the first lithium composite oxide.

[0069] The content of each element constituting M3 in the second mixture may be within a range of two of 0.3 mol, 0.4 mol, 0.5 mol, and 0.6 mol.

[0070] The content of the M2 component precursor in the second mixture may be within a range of two of 0.9 mol, 1.0 mol, 1.1 mol, 1.2 mol, 1.3 mol, 1.4 mol, 1.5 mol, 1.6 mol, 1.7 mol, and 1.8 mol per 100 mol of the first lithium composite oxide.

[0071] The second mixture may be fired in an oxygen atmosphere, thereby producing an oxide. The temperature at which the second mixture is fired may be higher than the temperature at which the first mixture is fired.

[0072] The second mixture may be fired at a temperature in the range of 650°C to 750°C. The firing temperature of the second mixture may be within the range of two of 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C and 750°C.

[0073] The firing of the second mixture may proceed for a time period ranging from 10 hours to 14 hours. The baking time of the second mixture may be within the range of two of the following values: 10 hours, 11 hours, 12 hours, 13 hours, and 14 hours.

[0074] The second lithium composite oxide may be washed with water at a temperature in the range of 20°C to 30°C. The water temperature during washing may be within the range of two of 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, and 30°C.

[0075] The second lithium composite oxide may be washed with water for 30 minutes or more. The second lithium composite oxide that has been washed with water can be dried at a temperature in the range of 250° C. to 400° C. The drying may be carried out in a dryer separate from that used for calcination.

[0076] The drying temperature of the water-washed second lithium composite oxide may be within a range of two of 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, and 400°C.

[0077] The heat treatment of the third mixture may be carried out in an oxygen atmosphere, thereby producing an oxide.

[0078] The heat treatment of the third mixture may be carried out for a time period of 8 hours or more. Specifically, the heat treatment of the third mixture may be carried out for a time period of 8 hours to 15 hours. More specifically, the heat treatment time of the third mixture may be within a range of two of 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, and 15 hours.

[0079] The M1 component may contain Zr, and the precursor of the M1 component may contain ZrO2. The M2 component may include Zr, Al, and Ti, and the precursor of the M2 component may include ZrO2, Al2O3, and TiO2. The M3 component may contain B. Also, the precursor of the M3 component may contain H3BO3. [Example]

[0080] Hereinafter, the present invention will be described with reference to specific experimental examples. The examples and comparative examples included in the experimental examples are merely illustrative of the content of the present invention and do not limit the scope of the appended claims. It is obvious to those skilled in the art that the embodiments of the present invention can be modified and changed in various ways within the scope and technical spirit of the present invention. It is also natural that such modifications and changes fall within the scope of the appended claims.

[0081] [Manufacturing example] Example 1. Positive electrode active material The positive electrode active material was prepared by the following procedure.

[0082] (1) A transition metal hydroxide containing nickel, cobalt, and manganese at 90.4 mol%, 8.4 mol%, and 1.2 mol%, respectively, is prepared.

[0083] (2) A first mixture containing the transition metal hydroxide, ZrO2, and a lithium compound (LiOH) is obtained. The ZrO2 content of the first mixture is 0.3 moles per 100 moles of the transition metal hydroxide. The lithium compound content of the first mixture is 105 moles per 100 moles of the transition metal hydroxide (Li / M=1.05).

[0084] (3) The first mixture is fired in an oxygen atmosphere at a temperature of 675° C. for 12 hours, thereby obtaining a first lithium composite oxide. (4) A second mixture containing the first lithium composite oxide, 0.1 mol of ZrO2, 0.6 mol of Al2O3, and 0.6 mol of TiO2 per 100 mol of the first lithium composite oxide is obtained.

[0085] (5) The second mixture is fired in an oxygen atmosphere at a temperature of 685° C. for 12 hours, thereby obtaining a second lithium composite oxide. (6) The second lithium composite oxide is mixed with water at room temperature for 30 minutes and washed with water.

[0086] (7) The water-washed second lithium composite oxide is dried in a dryer at a temperature of 300°C. (8) A third mixture containing the dried second lithium composite oxide and H3BO3 is obtained, wherein the H3BO3 content in the third mixture is 0.35 mol per 100 mol of the second lithium composite oxide. (9) The third mixture is heat-treated in an oxygen atmosphere at a temperature of 250° C. for 12 hours, thereby obtaining a positive electrode active material.

[0087] Examples 2 to 4 and Comparative Examples 1 to 3 The same process as in Example 1 was repeated, except that the H3BO3 content of the third mixture in (8) and the heat treatment temperature in (9) were changed according to Table 1 below.

[0088] [Evaluation method] 1.XRD analysis XRD analysis was performed on 5 g of the positive electrode active material samples of the examples and comparative examples. The I abc and c axis lengths were measured by XRD analysis. A Bruker D8 ENDEAVOR was used as the XRD analyzer. The analysis angle range was 10 degrees to 120 degrees, and the analysis condition was 11 degrees / min. The I abc and c axis lengths were calculated using the Rietveld refinement method. Measurements were performed three times for each sample. The results were summarized as arithmetic average values.

[0089] 2. Battery capacity characteristics A positive electrode slurry was prepared by dispersing 90 wt% of the positive electrode active materials of the Examples and Comparative Examples, 4.5 wt% of carbon black, and 5.5 wt% of PVDF binder in N-methyl-2-pyrrolidone (NMP). The positive electrode slurry was uniformly coated on a 15 μm-thick aluminum foil and dried under vacuum at 135°C. This produced a positive electrode for a lithium secondary battery.

[0090] A half-cell containing the positive electrode was fabricated. The counter electrode of the half-cell was lithium foil. The separator of the half-cell was a porous polyethylene membrane (Celgard 2300, thickness: 25 μm). The electrolyte of the half-cell was a 1.15 M LiPF6 solution in a solvent mixture of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in a volume ratio of 2:4:4 (EC:DMC:EMC). This electrolyte was injected into the positive electrode-separator-counter electrode cell.

[0091] The initial charge capacity and initial discharge capacity of the half-cell were measured using an electrochemical analyzer (Toyo, Toscat-3100) under the following measurement conditions: temperature of 25°C, voltage range of 2.0V to 4.6V, and discharge rate of 0.1C to 5.0C.

[0092] 3.Battery life characteristics The half cells prepared for the capacity characteristic evaluation were charged and discharged 50 times at 50° C. under the conditions of 1.0 C charge / 1.0 C discharge. The ratio (%) of the 50th discharge capacity to the 1st discharge capacity was calculated.

[0093] [Results and Discussion] The preparation conditions, characteristics, and performance evaluation results of the positive electrode active materials of Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1 below. The XRD analysis results of Examples 2, 5, and 6 and Comparative Examples 1 and 4 are shown in Figure 1. The XRD analysis results of Examples 1 to 4 and Comparative Examples 2 and 3 are shown in Figure 2.

[0094] [Table 1]

[0095] Table 1 shows that the initial charge-discharge efficiency and high-temperature life of the Examples were improved compared to the Comparative Examples. Here, the initial charge-discharge efficiency increased by up to 3.2%. The high-temperature life increased by up to 12.1%. This confirms that batteries made from positive electrode active materials that satisfy all of the characteristic conditions of the present invention can exhibit improved initial charge-discharge efficiency (capacity) and life (high-temperature life) compared to batteries that do not.

Claims

1. Particles containing a compound represented by the following chemical formula 1: an outer layer surrounding the particles; There is a positive electrode active material containing the I003 / I104 value of the positive electrode active material is within a range of 0.8 to 1.2, the (I102+I006) / (I101) value of the positive electrode active material is in the range of 0.448 to 0.467, The c-axis length of the positive electrode active material is in the range of 14.1870 Å to 14.1893 Å. [Chemical formula 1] Li ａ [(Ni ｘ Mn ｙ Co ｚ M1 ｗ )]O ２ In Chemical Formula 1, 0.9≦a≦1.1, 0.8≦x<1.0, 0≦y≦0.5, 0≦z≦0.5, 0<w<0.005, and x+y+z+w=1, and M1 includes at least one element selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W.

2. The outer layer is an M2 component distributed on a portion of the particle surface; and an M3 component that is different from the M2 component and is distributed on the remaining part of the particle surface; Including, The M2 component includes three or more elements selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W, 2. The positive electrode active material according to claim 1, wherein the M3 component comprises one or more selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W.

3. The positive electrode active material according to claim 2 , wherein the content of the M2 component is greater than the content of the M3 component.

4. 3. The positive electrode active material according to claim 2, wherein the content of the M2 component is in the range of 0.9 mol % to 1.8 mol %.

5. 3. The positive electrode active material according to claim 2, wherein the content of the M3 component is in the range of 0.25 mol % to 0.35 mol %.

6. The positive electrode active material according to claim 2 , wherein M1 contains Zr.

7. The positive electrode active material according to claim 2 , wherein the M2 component includes Zr, Al, and Ti.

8. The positive electrode active material according to claim 2 , wherein the M3 component contains B.

9. a positive electrode, a negative electrode, and an electrolyte; the positive electrode includes a positive electrode active material, The positive electrode active material includes particles containing a compound represented by the following Chemical Formula 1; and an outer layer surrounding the particles: the I003 / I104 value of the positive electrode active material is within a range of 0.8 to 1.2, the (I102+I006) / (I101) value of the positive electrode active material is in the range of 0.448 to 0.467, A secondary battery, wherein the c-axis length of the positive electrode active material is in the range of 14.1870 Å to 14.1893 Å. [Chemical formula 1] Li ａ [(Ni ｘ Mn ｙ Co ｚ M1 ｗ )]O ２ In Chemical Formula 1, 0.9≦a≦1.1, 0.8≦x<1.0, 0≦y≦0.5, 0≦z≦0.5, 0<w<0.005, and x+y+z+w=1, and M1 includes at least one element selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W.

10. providing hydroxides of transition metals including nickel, cobalt, and manganese; a step of calcining a first mixture containing the hydroxide of the transition metal, an M1 component precursor, and a lithium compound to obtain a first lithium composite oxide; a step of calcining a second mixture containing the first lithium composite oxide and an M2 component precursor to obtain a second lithium composite oxide; a step of washing the second lithium composite oxide with water; drying the second lithium composite oxide that has been washed with water; and heat-treating the third mixture containing the dried second lithium composite oxide and the M3 component precursor; Including, The M1 component includes one or more selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W, The M2 component includes three or more elements selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W, The M3 component includes one or more selected from the group consisting of Al, Ti, Zr, Mg, Zn, B, Mo, Fe, Co, Ni, Ba, and W, The M3 component is different from the M2 component, the content of the M3 component precursor in the third mixture is within a range of 0.25 mol to 0.35 mol per 100 mol of the dried second lithium composite oxide, The heat treatment of the third mixture is carried out at a temperature in the range of 250°C to 400°C.

11. The method for producing a positive electrode active material according to claim 10 , wherein the content of the M1 component precursor in the first mixture is less than 0.5 mol per 100 mol of the hydroxide of the transition metal.

12. 11. The method for producing a positive electrode active material according to claim 10, wherein the content of the M2 component precursor in the second mixture is within a range of 0.9 mol to 1.8 mol per 100 mol of the first lithium composite oxide.

13. The M1 component contains Zr, The M2 component includes Zr, Al, and Ti, The method for producing a positive electrode active material according to claim 10 , wherein the M3 component contains B.

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