Method for manufacturing positive electrode active material

Abstract

The present invention relates to a method for manufacturing a positive electrode active material and, more specifically, to a method for manufacturing a positive electrode active material, the method comprising the steps of: (A) preparing a lithium composite transition metal oxide by mixing a positive electrode active material precursor and a lithium (Li)-containing raw material and then firing the mixture; and (B) forming a coating layer on the lithium composite transition metal oxide by mixing the lithium composite transition metal oxide and a coating raw material and heat-treating same, wherein the heat treatment includes a temperature increasing section for increasing the temperature and a maintaining section for maintaining the temperature, and includes a section for injecting steam only in the temperature increasing section.

Description

Method for manufacturing positive electrode active material

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0107877, filed August 17, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a method for manufacturing a positive electrode active material.

[0005]

[0006] With the recent technological development and increasing demand for mobile devices and electric vehicles, the demand for secondary batteries as an energy source is rapidly increasing. Among these secondary batteries, lithium secondary batteries, which boast high energy density and voltage, long cycle life, and low self-discharge rates, are commercialized and widely used.

[0007] Lithium transition metal oxides such as lithium cobalt oxide such as LiCoO2, lithium nickel oxide such as LiNiO2, lithium manganese oxide such as LiMnO2 or LiMn2O4, and lithium iron phosphate compounds such as LiFePO4 have been developed as positive electrode active materials for lithium secondary batteries, and recently, Li[Ni a Co b Mn c ]O2, Li[Ni a Co b Al c ]O2, Li[Ni a Co b Mn c Al d ] Lithium composite transition metal oxides containing two or more transition metals, such as O2, have been developed and are widely used.

[0008] In particular, with the recent technological advancements in electric vehicles and other devices, the demand for high-capacity secondary batteries is increasing, and accordingly, research on cathodes using high-nickel (High-Ni) cathode active materials with excellent capacity characteristics is being actively conducted.

[0009] High-nickel cathode active materials are manufactured by mixing precursors and lithium raw materials, followed by calcination. Since calcination is performed at relatively low temperatures, the amount of residual lithium, a byproduct, on the surface of the cathode active material increases. This residual lithium, in the form of LiOH and / or Li2CO3, reacts with electrolytes and other components within the battery, generating gas and causing swelling.

[0010] If a washing process is introduced to remove these byproducts, the surface of the positive electrode active material can be damaged during the washing process, resulting in reduced capacity and rate characteristics and complicated process steps. Furthermore, the difference in surface energy between the positive electrode active material surface and the coating raw material after washing makes it difficult to form a uniform coating layer, and excessive use of the coating raw material can occur.

[0011] Therefore, it is necessary to secure a technology to reduce byproducts on the surface of the positive electrode active material and improve coating efficiency.

[0012]

[0013] [Prior Art Literature]

[0014] [Patent Document]

[0015] (Patent Document 1) Korean Patent Publication No. 10-2020-0105474

[0016]

[0017] In order to solve the above problems, the technical task of the present invention is to provide a method for manufacturing a cathode active material that can reduce by-products and improve coating efficiency on the surface of a lithium composite transition metal oxide.

[0018]

[0019] To solve the above problem, the present invention provides a method for manufacturing a positive electrode active material.

[0020] (1) The present invention provides a method for producing a positive electrode active material, comprising: (A) a step of mixing a positive electrode active material precursor and a lithium (Li)-containing raw material, and then calcining to produce a lithium composite transition metal oxide; and (B) a step of mixing the lithium composite transition metal oxide and a coating raw material, and then heat-treating to form a coating layer on the lithium composite transition metal oxide; wherein the heat treatment includes a temperature-raising section for raising a temperature and a temperature-maintaining section, and includes a section for introducing steam only in the temperature-raising section.

[0021] (2) The present invention provides a method for producing a positive electrode active material, wherein, in the above (1), the positive electrode active material precursor has a composition represented by the following chemical formula 1.

[0022] [Chemical Formula 1]

[0023] Ni a Mn b Co c M 1 d (OH)2

[0024] In the above chemical formula 1,

[0025] M 1 is at least one selected from Al, Zr, W, Mg, Ti, Y and B, and 0.5≤a<1, 0≤b<0.5, 0≤c<0.5, 0≤d≤0.1.

[0026] (3) The present invention provides a method for producing a positive electrode active material, wherein the calcination is performed at a temperature of 700°C to 1,000°C in the above (1) or (2).

[0027] (4) The present invention provides a method for producing a positive electrode active material, wherein the lithium composite transition metal oxide has a composition represented by the following chemical formula 2, in any one of the above (1) to (3).

[0028] [Chemical Formula 2]

[0029] Li 1+x1 Ni a1 Mn b1 Co c1 M 2 d1 O2

[0030] In the above chemical formula 2, M 2 is at least one selected from Al, Zr, W, Mg, Ti, Y, and B, and 0.0≤x1≤0.10, 0.5≤a1<1, 0≤b1<0.5, 0≤c1<0.5, 0≤d1≤0.1.

[0031] (5) The present invention provides a method for producing a positive electrode active material, wherein the lithium composite transition metal oxide is in the form of a single particle, in any one of the above (1) to (4).

[0032] (6) The present invention provides a method for producing a positive electrode active material, which does not include a washing step, in any one of the above (1) to (5).

[0033] (7) The present invention provides a method for producing a positive electrode active material, wherein the coating raw material is a hydroxide containing at least one selected from Co, Al, and Nb, in any one of the above (1) to (6).

[0034] (8) The present invention provides a method for producing a positive electrode active material, wherein the coating raw material is cobalt hydroxide, in any one of the above (1) to (7).

[0035] (9) The present invention provides a method for producing a positive electrode active material, wherein the coating raw material is mixed in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the lithium composite transition metal oxide in any one of the above (1) to (8).

[0036] (10) The present invention provides a method for manufacturing a positive electrode active material, wherein the heating section includes a section in which steam is introduced at a temperature of 600°C or lower in any one of the above (1) to (9).

[0037] (11) The present invention provides a method for manufacturing a positive electrode active material, wherein in any one of the above (1) to (10), the temperature rising section has a temperature rising rate of 1°C / min to 10°C / min.

[0038] (12) The present invention provides a method for manufacturing a positive electrode active material, wherein, in any one of (1) to (11), the water vapor is introduced in an amount such that the moisture content (χ) according to the following formula 1 becomes 1% to 10%.

[0039] [Formula 1]

[0040]

[0041] In the above equation 1,

[0042] The above α is the mass (g) of the lithium composite transition metal oxide and the coating raw material immediately after passing through the steam injection section, and the above β is the mass (g) of the lithium composite transition metal oxide and the coating raw material after passing through the steam injection section and completely drying them.

[0043] (13) The present invention provides a method for manufacturing a positive electrode active material, wherein the section in which the water vapor is injected is performed under an oxidizing atmosphere in any one of the above (1) to (12).

[0044] (14) The present invention provides a method for manufacturing a positive electrode active material, wherein the maintenance section performs heat treatment while maintaining the temperature at 500°C to 900°C in any one of the above (1) to (13).

[0045] (15) The present invention provides a method for manufacturing a positive electrode active material, wherein the maintenance period is performed for 1 to 12 hours in any one of the above (1) to (14).

[0046] (16) The present invention provides a method for manufacturing a positive electrode active material, wherein the maintenance section does not include a section for introducing water vapor in any one of the above (1) to (15).

[0047]

[0048] The manufacturing method of the present invention can reduce byproducts on the surface of a positive electrode active material by including a section for introducing water vapor during a temperature-raising section during heat treatment for forming a coating layer, and can form a thin and uniform coating layer as well as improve coating efficiency.

[0049]

[0050] Figure 1 is an EPMA (ELECTRON PROBE MICROANALYSIS) mapping image of the positive electrode active material manufactured in Example 1.

[0051] Figure 2 is an EPMA mapping image of the positive electrode active material manufactured in Example 2.

[0052] Figure 3 is an EPMA mapping image of the positive electrode active material manufactured in Example 3.

[0053] Figure 4 is an EPMA mapping image of the positive electrode active material manufactured in Comparative Example 1.

[0054]

[0055] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0056] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner.

[0057] It should be understood that the terms “include,” “have,” or “have” used in this specification are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0058] In this specification, the term 'on' means not only when a configuration is formed directly on the top surface of another configuration, but also when a third configuration is interposed between these configurations.

[0059] In this specification, the single particle form is a concept that contrasts with the spherical secondary particle form formed by agglomeration of primary particles having a size of several nm to less than 0.5 μm manufactured by a conventional method, and refers to a cathode active material and / or lithium composite transition metal oxide having a non-spherical particle form formed by agglomeration of primary particles having a size of 0.5 μm or more.

[0060] For example, in the present invention, the cathode active material in the form of a single particle may be a single particle composed of one primary particle of 0.5 μm or more, or may be an aggregate of several primary particles of 0.5 μm or more. Meanwhile, the term "primary particle" refers to the smallest particle unit recognized when observing the cathode active material through a scanning electron microscope.

[0061] In this specification, the 'moisture content' may be measured using a heating type moisture meter (e.g., AND's MX-50). Specifically, after placing about 5 g of a sample in a sample dish inside the device, the lid of the device is closed and the temperature of the sample dish is set to 100°C to 150°C, thereby evaporating the moisture contained in the powder sample and measuring the degree of mass reduction. At this time, the point at which the mass no longer decreases is referred to as a completely dried state. The moisture content may be expressed as a percentage (%) by measuring the mass of the sample before and after complete drying and expressing the difference in mass (g) of the sample before and after complete drying with respect to the mass (g) of the sample before complete drying.

[0062]

[0063] Method for manufacturing positive electrode active material

[0064] Hereinafter, a method for manufacturing a positive electrode active material according to the present invention will be described.

[0065]

[0066] A method for manufacturing a cathode active material according to the present invention comprises the steps of (A) mixing a cathode active material precursor and a lithium (Li)-containing raw material, and then calcining to manufacture a lithium composite transition metal oxide; and (B) mixing the lithium composite transition metal oxide and a coating raw material, and then heat-treating to form a coating layer on the lithium composite transition metal oxide; wherein the heat treatment includes a temperature-raising section for raising a temperature and a temperature-maintaining section for maintaining the temperature, and includes a section for introducing steam only in the temperature-raising section.

[0067]

[0068] Hereinafter, the method for manufacturing a positive electrode active material according to the present invention will be described in more detail.

[0069]

[0070] (A) Step

[0071] It includes a step of mixing a positive electrode active material precursor and a lithium (Li)-containing raw material and then calcining them to produce a lithium composite transition metal oxide.

[0072]

[0073] According to one embodiment of the present invention, the positive electrode active material precursor may have a composition represented by the following chemical formula 1.

[0074] [Chemical Formula 1]

[0075] Ni a Mn b Co c M 1 d (OH)2

[0076] In the above chemical formula 1,

[0077] M 1 is at least one selected from Al, Zr, W, Mg, Ti, Y and B,

[0078] 0.5≤a<1, 0≤b<0.5, 0≤c<0.5, 0≤d≤0.1.

[0079] Above M 1 is a doping element, specifically the above M 1 It may be at least one selected from Al, Zr, W, Mg, Ti, Y and B.

[0080] The above a is the molar ratio of nickel (Ni) among the total metals in the positive electrode active material precursor, and may be 0.5 or more, 0.7 or more, 0.8 or more, 0.85 or more, or 0.88 or more, and may be 0.9 or less, 0.95 or less, 0.98 or less, or less than 1. When a satisfies the above range, a high energy density is exhibited, and high-capacity characteristics can be realized.

[0081] The above b is the molar ratio of manganese (Mn) among the total metals in the positive electrode active material precursor, and may be 0 or more, 0.03 or more, 0.05 or more, or 0.07 or more, and may be 0.1 or less, 0.2 or less, 0.3 or less, 0.4 or less, or less than 0.5.

[0082] The above c is the molar ratio of cobalt (Co) among the total metals in the positive electrode active material precursor, and may be 0 or more, 0.01 or more, 0.02 or more, or 0.03 or more, and may be 0.05 or less, 0.1 or less, 0.2 or less, 0.3 or less, 0.4 or less, or less than 0.5.

[0083] The above d is M among the total metals in the positive electrode active material precursor. 1 The molar ratio may be 0 or more, 0.01 or more, 0.02 or more, 0.03 or more, or 0.04 or more, and may be 0.05 or less, 0.06 or less, 0.07 or less, 0.08 or less, or 0.1 or less.

[0084] When the above a, b, c, and d satisfy the above ranges, a positive electrode active material having excellent energy density and high capacity characteristics can be realized.

[0085] The transition metal hydroxide having the composition represented by the above chemical formula 1 can be a commercially available product or can be manufactured according to a method for manufacturing a transition metal hydroxide, such as a coprecipitation method, which is well known in the art.

[0086]

[0087] The above lithium (Li)-containing raw material may be a lithium-containing sulfate, nitrate, carbonate, hydroxide, etc. Specifically, the lithium raw material may be Li2CO3, LiNO3, LiNO2, LiOH, LiOHㆍH2O, LiH, LiBr, LiI, Li2O, Li2SO4, etc.

[0088]

[0089] The above-described positive electrode active material precursor and lithium (Li)-containing raw material may be mixed so that the molar ratio (M:Li) of the transition metal (M) contained in the positive electrode active material precursor and the lithium (Li) contained in the lithium (Li)-containing raw material is 1:1.00 to 1.10. In this case, not only can excessive lithium be prevented from entering the positive electrode active material structure, but the content of unreacted residual lithium can also be reduced.

[0090]

[0091] The above mixing can be done by dry mixing or wet mixing. When mixing each component through dry mixing, the firing process can be performed without a separate drying process. When mixing each component through wet mixing, the composition can be prepared by adding it to a solvent, specifically water, or a mixture of water and an organic solvent (specifically alcohol, etc.) that can be uniformly mixed with water. Alternatively, a solution containing each raw material, specifically an aqueous solution, is prepared, mixed, and the mixed components are spray-dried before the firing process is performed.

[0092] Each raw material and positive electrode active material precursor can be used in an appropriate amount considering the content of each metal element in the final lithium composite metal oxide.

[0093]

[0094] According to one embodiment of the present invention, the sintering may be performed at a temperature of 700°C or higher, 750°C or higher, 800°C or higher, 850°C or lower, 900°C or lower, 950°C or lower, or 1,000°C or lower. In addition, the sintering may be performed for 10 hours or higher, 15 hours or higher, or 20 hours or higher, 25 hours or lower, 30 hours or lower, or 40 hours or lower, and the sintering may be performed under an oxygen atmosphere. When performed within the above temperature range, time range, and atmosphere, the lithium (Li)-containing raw material is efficiently melted, and the reaction between the positive active material precursor and the lithium (Li)-containing raw material is promoted, thereby efficiently growing lithium composite transition metal oxide particles.

[0095]

[0096] According to one embodiment of the present invention, the lithium composite transition metal oxide may have a composition represented by the following chemical formula 2.

[0097] [Chemical Formula 2]

[0098] Li 1+x1 Ni a1 Mn b1 Co c1 M 2 d1 O2

[0099] In the above chemical formula 2,

[0100] M 2 is at least one selected from Al, Zr, W, Mg, Ti, Y and B,

[0101] 0.0≤x1≤0.10, 0.5≤a1<1, 0≤b1<0.5, 0≤c1<0.5, 0.0≤d1≤0.1.

[0102] Above M 2 is a doping element, specifically the above M 2 M may be at least one selected from Al, Zr, W, Mg, Ti, Y and B. 2Although not necessarily included, if included in an appropriate amount, the particle shape of the positive electrode active material can be improved and the stability of the crystal structure can be enhanced.

[0103] The above x1 may be 0 or greater, 0.01 or greater, 0.02 or greater, 0.03 or greater, or 0.04 or greater, and may be 0.05 or less, 0.06 or less, 0.07 or less, 0.08 or less, or 0.1 or less.

[0104] The above a1 is the molar ratio of nickel (Ni) among all metals excluding lithium in the lithium composite transition metal oxide, and may be 0.5 or more, 0.7 or more, 0.8 or more, 0.85 or more, or 0.88 or more, and may be 0.9 or less, 0.95 or less, 0.98 or less, or less than 1. When a1 satisfies the above range, a high energy density is exhibited, and high-capacity characteristics can be realized.

[0105] The above b1 is the molar ratio of manganese (Mn) among all metals excluding lithium in the lithium composite transition metal oxide, and may be 0 or more, 0.03 or more, 0.05 or more, or 0.07 or more, and may be 0.1 or less, 0.2 or less, 0.3 or less, 0.4 or less, or less than 0.5.

[0106] The above c1 is the molar ratio of cobalt (Co) among all metals excluding lithium in the lithium composite transition metal oxide, and may be 0 or more, 0.01 or more, 0.02 or more, or 0.03 or more, and may be 0.05 or less, 0.1 or less, 0.2 or less, 0.3 or less, 0.4 or less, or less than 0.5.

[0107] The above d1 is M among all metals except lithium in the lithium composite transition metal oxide. 2The molar ratio of d1 may be 0 or more, 0.01 or more, 0.02 or more, 0.03 or more, or 0.04 or more, and may be 0.05 or less, 0.06 or less, 0.07 or less, 0.08 or less, or 0.1 or less. When d1 satisfies the above range, the stability of the crystal structure of the positive electrode active material may be improved, and the output characteristics, capacity characteristics, and life characteristics may be improved.

[0108] When the above x1, a1, b1, c1, and d1 satisfy the above ranges, a positive electrode active material having excellent energy density and high capacity characteristics can be obtained.

[0109]

[0110] According to one embodiment of the present invention, the lithium composite transition metal oxide may be in the form of a single particle. When the lithium composite transition metal oxide is in the form of a single particle, the structural stability of a cathode active material including the lithium composite transition metal oxide can be enhanced. In this regard, when rolling for electrode manufacture or operating a cell, particle breakage (micro / macro-crack) due to grain boundaries can be suppressed, the grain boundary area in contact with the electrolyte can be reduced, and gas generation due to side reactions with the electrolyte can be reduced, thereby improving the life characteristics of a secondary battery.

[0111]

[0112] (B) Step

[0113] A step of mixing the lithium composite transition metal oxide and the coating raw material, and then performing a heat treatment to form a coating layer on the lithium composite transition metal oxide; wherein the heat treatment includes a temperature-raising section for raising the temperature and a temperature-maintaining section for maintaining the temperature, and includes a section for introducing steam only in the temperature-raising section.

[0114]

[0115] Conventionally, when forming a coating layer on a lithium composite transition metal oxide, excessive amounts of coating raw materials were used or a washing treatment was performed to reduce byproducts on the surface of the lithium composite transition metal oxide. However, when excessive amounts of coating raw materials were used, byproducts still existed and efficiency was reduced. In addition, when a washing treatment was performed, the surface of the positive electrode active material was damaged, the process steps became complicated, and it was uneconomical.

[0116] The present inventors have discovered that when forming a coating layer on a lithium composite transition metal oxide, by mixing the lithium composite transition metal oxide and the coating raw material and then injecting water vapor at a specific section during the heat treatment, by-products on the surface of the lithium composite transition metal oxide can be reduced, the coating layer can be formed thinly and uniformly, and the coating efficiency can be improved, thereby completing the present invention.

[0117] Meanwhile, when steam is introduced in the temperature-maintaining section during heat treatment, there is a problem that residual lithium, a by-product on the surface of the lithium composite transition metal oxide, increases as the steam promotes the reduction reaction of Li2O and H2O, and the coating efficiency decreases.

[0118]

[0119] According to one embodiment of the present invention, the coating layer may be in a discontinuous form or a continuous form.

[0120]

[0121] According to one embodiment of the present invention, a washing step may not be included. As a result, damage to the surface of the positive electrode active material is prevented, the process is simplified, and economical effects are achieved.

[0122]

[0123] According to one embodiment of the present invention, the coating raw material may be a hydroxide containing at least one selected from Co, Al, and Nb. In particular, in the case of cobalt hydroxide, the resistance characteristics of the lithium transition metal oxide can be improved, thereby improving the output characteristics and capacity characteristics.

[0124]

[0125] According to one embodiment of the present invention, the coating raw material may be mixed in an amount of 0.5 parts by weight or more, 1 part by weight or more, 1.5 parts by weight or more, or 2 parts by weight or more, and 3 parts by weight or less, 4 parts by weight or less, or 5 parts by weight or less, based on 100 parts by weight of the lithium composite transition metal oxide. When the mixing amount of the coating raw material is within the above range, the coating layer is thin and uniform, the coating efficiency is improved, and there is an economical effect.

[0126]

[0127] Meanwhile, the heat treatment includes a temperature-raising section for raising the temperature and a holding section for maintaining the temperature, and includes a section for injecting steam only in the temperature-raising section. That is, the section for injecting steam exists only in the temperature-raising section, and sections other than the temperature-raising section do not include sections for injecting steam. Specifically, the holding section may not include a section for injecting steam. If the section for injecting steam is included in the temperature-raising section, the steam promotes the reaction between the coating raw material and the residual lithium, and an additional washing process may not be performed to remove the byproducts on the surface, thereby reducing the byproducts on the surface of the lithium composite transition metal oxide and simplifying the process steps compared to the prior art. Meanwhile, if the section for injecting steam is included in other sections other than the temperature-raising section, specifically, the holding section, the steam promotes the reduction reaction of Li2O and H2O, which causes a problem in that the residual lithium as a byproduct on the surface of the lithium composite transition metal oxide increases, and the coating efficiency decreases.

[0128]

[0129] According to one embodiment of the present invention, the temperature-raising section may include a section in which steam is introduced at a temperature of 600°C or lower. Specifically, it may include a section in which steam is introduced at a temperature of 0°C to 250°C, a section in which steam is introduced at a temperature of 250°C to 500°C, or a section in which steam is introduced at a temperature of 0°C to 500°C. When the section in which steam is introduced is within the temperature range, the reaction between the coating raw material and residual lithium can be efficiently controlled, and a sufficient amount of heat required for the reaction can be supplied.

[0130]

[0131] According to one embodiment of the present invention, the temperature increasing section may have a temperature increasing rate of 1°C / min or more, 2°C / min or more, 3°C / min or more, or 4°C / min or more, and may be 6°C / min or less, 7°C / min or less, 8°C / min or less, 9°C / min or less, or 10°C / min or less. When the temperature increasing rate in the temperature increasing section is within the above range, the production yield is excellent, and the temperatures of the reactor, the lithium composite transition metal oxide, and the coating raw material are similar, so that all of the heat amount of the set maintenance temperature can be received. In particular, when the temperature increasing rate is 5°C / min, the heat amount required for the reaction can be efficiently supplied.

[0132]

[0133] According to one embodiment of the present invention, the water vapor may be introduced in an amount such that the moisture content (χ) according to the following equation 1 may be 1% or more, 2% or more, 3% or more, 4% or more, or 5% or more, and 6% or less, 7% or less, 8% or less, 9% or less, or 10% or less.

[0134] [Formula 1]

[0135]

[0136] In the above equation 1,

[0137] The above α is the mass (g) of the lithium composite transition metal oxide and the coating raw material immediately after passing through the steam injection section, and the above β is the mass (g) of the lithium composite transition metal oxide and the coating raw material after passing through the steam injection section and completely drying them.

[0138]

[0139] According to one embodiment of the present invention, the steam injection section may be performed under an oxidizing atmosphere. In this case, the atmosphere necessary for the reaction can be provided, effectively controlling the reaction between the coating raw material and the residual lithium.

[0140]

[0141] According to one embodiment of the present invention, the maintenance section may be 500°C or higher, 600°C or higher, or 700°C or higher, and the heat treatment may be performed while maintaining the temperature at 800°C or lower, 850°C or lower, or 900°C or lower. When the temperature of the maintenance section is within the above range, the coating raw material is melted, and there is an effect of stabilizing the surface of the positive electrode active material through recrystallization of the surface of the lithium composite transition metal oxide.

[0142]

[0143] According to the present invention, the maintenance period may be 1 hour or more, or 2 hours or more, and may be performed for 3 hours or less, 5 hours or less, or 12 hours or less. When the maintenance period time is within the above range, sufficient thermal energy is supplied to the lithium composite transition metal oxide and the coating raw material, and the effect of making the coating uniform overall is achieved.

[0144]

[0145] positive electrode active material

[0146] In addition, the present invention provides a positive electrode active material manufactured by the manufacturing method described above.

[0147] The cathode active material according to the present invention is a cathode active material manufactured by the manufacturing method described above, and is a cathode active material having a uniform coating layer on a lithium composite transition metal oxide. The coating layer may have a small concentration deviation of coating elements.

[0148]

[0149] anode

[0150] In addition, the present invention provides a positive electrode for a lithium secondary battery including the positive electrode active material described above.

[0151] Specifically, the positive electrode includes a positive electrode current collector, and a positive electrode active material layer positioned on at least one surface of the positive electrode current collector and including the positive electrode active material described above.

[0152] The positive electrode current collector is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. may be used. In addition, the positive electrode current collector may typically have a thickness of 3 to 500 μm, and fine unevenness may be formed on the surface of the positive electrode current collector to increase the adhesive strength of the positive electrode active material. For example, the positive electrode current collector may be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric.

[0153]

[0154] The above positive electrode active material layer may include a conductive material and a binder together with the positive electrode active material.

[0155] At this time, the positive electrode active material may be included in an amount of 80 to 99 wt%, more specifically 85 to 98 wt%, based on the total weight of the positive electrode active material layer. When included in the above content range, excellent capacity characteristics can be exhibited.

[0156] At this time, the conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without any special restrictions. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; metal powder or metal fiber such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like, and one type alone or a mixture of two or more types thereof may be used. The conductive material may be included in an amount of 1 to 30 wt% based on the total weight of the positive electrode active material layer.

[0157]

[0158] The above binder serves to improve the adhesion between positive electrode active material particles and the adhesive strength between the positive electrode active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluoroelastomer, or various copolymers thereof, and one of these may be used alone or a mixture of two or more thereof. The binder may be included in an amount of 1 to 30 wt% based on the total weight of the positive electrode active material layer.

[0159]

[0160] The above-mentioned positive electrode can be manufactured according to a conventional positive electrode manufacturing method, except that the above-mentioned positive electrode active material is used. Specifically, the positive electrode composite material, prepared by dissolving or dispersing the above-mentioned positive electrode active material and optionally a binder and a conductive agent in a solvent, is applied onto a positive electrode current collector, and then dried and rolled. At this time, the types and contents of the positive electrode active material, binder, and conductive agent are as described above.

[0161]

[0162] The solvent may be a solvent generally used in the relevant technical field, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water. One of these may be used alone or a mixture of two or more thereof may be used. The amount of the solvent used is sufficient to dissolve or disperse the positive electrode active material, conductive material, and binder, taking into account the coating thickness and manufacturing yield of the slurry, and to have a viscosity that can exhibit excellent thickness uniformity when applied thereafter for manufacturing the positive electrode.

[0163]

[0164] Alternatively, the positive electrode may be manufactured by casting the positive electrode composite on a separate support, then peeling the resulting film from the support and laminating it on a positive electrode current collector.

[0165]

[0166] lithium secondary battery

[0167] In addition, the present invention can manufacture an electrochemical device including the positive electrode. The electrochemical device may be a battery, a capacitor, or the like, and more specifically, a lithium secondary battery.

[0168] The lithium secondary battery specifically includes a positive electrode, a negative electrode positioned opposite the positive electrode, and a separator and electrolyte interposed between the positive electrode and the negative electrode. Since the positive electrode is the same as described above, a detailed description thereof will be omitted, and only the remaining components will be described in detail below.

[0169] In addition, the lithium secondary battery may optionally further include a battery container that houses the electrode assembly of the positive electrode, the negative electrode, and the separator, and a sealing member that seals the battery container.

[0170]

[0171] In the above lithium secondary battery, the negative electrode includes a negative electrode current collector and a negative electrode active material layer positioned on the negative electrode current collector.

[0172] The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, the negative electrode current collector can typically have a thickness of 3 ㎛ to 500 ㎛, and like the positive electrode current collector, fine unevenness can be formed on the surface of the current collector to strengthen the bonding strength of the negative electrode active material. For example, it can be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0173]

[0174] The above negative electrode active material layer optionally includes a binder and a conductive material together with the negative electrode active material.

[0175] As the negative electrode active material, a compound capable of reversible intercalation and deintercalation of lithium may be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, or Al alloy; SiO β (0<β<2), SnO2, vanadium oxide, lithium vanadium oxide, and other metal oxides capable of doping and dedoping lithium; or composites containing the above metallic compounds and carbonaceous materials, such as Si-C composites or Sn-C composites, and any one or a mixture of two or more of these may be used. In addition, a metallic lithium thin film may be used as the negative electrode active material. In addition, both low-crystalline carbon and high-crystalline carbon may be used as the carbonaceous material. Representative examples of low-crystalline carbon include soft carbon and hard carbon, and representative examples of high-crystalline carbon include natural graphite or artificial graphite in the form of amorphous, plate-like, flaky, spherical, or fiber-like forms, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch derived cokes.

[0176] The above negative electrode active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of the negative electrode active material layer.

[0177]

[0178] The above binder is a component that assists in bonding between the conductive material, the active material, and the current collector, and can typically be added in an amount of 0.1 wt% to 10 wt% based on the total weight of the negative electrode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0179] The conductive agent is a component for further improving the conductivity of the negative electrode active material, and may be added in an amount of 10 wt% or less, preferably 5 wt% or less, based on the total weight of the negative electrode active material layer. The conductive agent is not particularly limited as long as it has conductivity and does not cause a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber or metal fiber; fluorinated carbon; metal powder such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0180]

[0181] The above negative electrode active material layer can be manufactured by applying and drying a negative electrode composite prepared by dissolving or dispersing a negative electrode active material, and optionally a binder and a conductive material in a solvent, on a negative electrode current collector, or by casting the negative electrode composite on a separate support and then laminating the obtained film by peeling it off from the support on a negative electrode current collector.

[0182]

[0183] Meanwhile, in the lithium secondary battery, the separator separates the negative electrode and the positive electrode and provides a passage for lithium ions to move. Any separator commonly used in lithium secondary batteries can be used without special restrictions, and in particular, one having low resistance to ion movement of the electrolyte and excellent electrolyte moisture absorption capacity is preferable. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof, can be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. can also be used. In addition, a coated separator containing a ceramic component or a polymer material to secure heat resistance or mechanical strength can be used, and can optionally be used in a single-layer or multi-layer structure.

[0184]

[0185] In addition, examples of the electrolyte used in the present invention include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of lithium secondary batteries.

[0186] Specifically, the electrolyte may include an organic solvent and a lithium salt.

[0187] The organic solvent may be used without any particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; Carbonate solvents such as dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R represents a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, a carbonate solvent is preferable, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery and a linear carbonate compound having low viscosity (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate, etc.) is more preferable.

[0188] The above lithium salt can be used without any special limitation as long as it is a compound that can provide lithium ions used in a lithium secondary battery. Specifically, the above lithium salt is LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2) 2. LiCl, LiI, or LiB(C2O4)2 can be used. The concentration of the lithium salt is preferably within the range of 0.1 to 4.0 M, and preferably, 0.1 to 2.0 M. When the concentration of the lithium salt is within the above range, the electrolyte can exhibit excellent electrolyte performance because it has appropriate conductivity and viscosity, and lithium ions can move effectively.

[0189]

[0190] In addition to the electrolyte components, the electrolyte may further include one or more additives, such as haloalkylene carbonate compounds such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ethers, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing battery capacity decrease, and improving the discharge capacity of the battery. At this time, the additives may be included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the total weight of the electrolyte.

[0191]

[0192] As described above, a lithium secondary battery including a cathode active material according to the present invention exhibits excellent life characteristics and other stable characteristics, and is therefore useful in portable devices such as mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs).

[0193] Accordingly, according to another embodiment of the present invention, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided.

[0194] The above battery module or battery pack can be used as a power source for one or more medium- to large-sized devices, such as a power tool; an electric vehicle (EV), a hybrid electric vehicle, and a plug-in hybrid electric vehicle (PHEV); or a power storage system.

[0195] There is no particular limitation on the external shape of the lithium secondary battery of the present invention, but it may be a cylindrical shape using a can, a square shape, a pouch shape, or a coin shape.

[0196] The lithium secondary battery according to the present invention can be used not only as a battery cell used as a power source for a small device, but can also be preferably used as a unit battery in a medium- to large-sized battery module including a plurality of battery cells.

[0197]

[0198] Hereinafter, the present invention will be described in detail with reference to examples. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention should not be construed as being limited to the examples described below. These examples are provided to more fully explain the present invention to those of ordinary skill in the art.

[0199]

[0200] Examples and Comparative Examples

[0201] Example 1

[0202] Ni 0.885 Co 0.035 Mn 0.08 (OH)2 and LiOH were mixed so that the molar ratio of (Ni+Co+Mn):Li was 1:1.03, and then calcined at 800°C for 22 hours in an oxidizing atmosphere to obtain LiNi 0.885 Co 0.035 Mn 0.08 A lithium composite transition metal oxide in the form of a single particle having a composition represented by O2 was prepared.

[0203] After mixing 2.5 parts by weight of Co(OH)2 with respect to 100 parts by weight of the above lithium composite transition metal oxide, steam was introduced into the kiln at a rate of 2.0 kg / hour and the temperature was increased from 0°C to 500°C at a rate of 5°C / min in an oxidizing atmosphere. Then, the steam introduction was stopped and the temperature was increased from 500°C to 700°C at a rate of 5°C / min in an oxidizing atmosphere. Then, a heat treatment was performed while maintaining the temperature at 700°C for 2 hours in an oxidizing atmosphere, thereby manufacturing a cathode active material in which a coating layer including Co was formed on the lithium composite transition metal oxide.

[0204]

[0205] Example 2

[0206] In Example 1, 100 parts by weight of the lithium composite transition metal oxide was mixed with 2.5 parts by weight of Co(OH)2, and then steam was introduced into the kiln at a rate of 2.0 kg / hour and the temperature was increased from 0°C to 250°C at a rate of 5°C / min in an oxidizing atmosphere. Then, the steam introduction was stopped and the temperature was increased from 250°C to 700°C at a rate of 5°C / min in an oxidizing atmosphere. Then, a heat treatment was performed at 700°C for 2 hours in an oxidizing atmosphere to manufacture a cathode active material having a coating layer including Co formed on the lithium composite transition metal oxide.

[0207]

[0208] Example 3

[0209] In Example 1, 100 parts by weight of the lithium composite transition metal oxide was mixed with 2.5 parts by weight of Co(OH)2, and the temperature was increased from 0°C to 250°C at a rate of 5°C / min. Steam was introduced into the kiln at a rate of 2.0 kg / hr, and the temperature was increased from 250°C to 500°C at a rate of 5°C / min in an oxidizing atmosphere. Then, the introduction of steam was stopped, and the temperature was increased from 250°C to 700°C at a rate of 5°C / min in an oxidizing atmosphere. Then, heat treatment was performed at 700°C for 2 hours in an oxidizing atmosphere, thereby manufacturing a cathode active material in which a coating layer including Co was formed on the lithium composite transition metal oxide.

[0210]

[0211] Comparative Example 1

[0212] After mixing 2.5 parts by weight of Co(OH)2 with 100 parts by weight of the lithium composite transition metal oxide manufactured in Example 1, the temperature was increased from 0°C to 700°C at a rate of 5°C / min in an oxidizing atmosphere, and then heat-treated while maintaining the temperature at 700°C for 2 hours in an oxidizing atmosphere to manufacture a positive electrode active material in which a coating layer including Co was formed on the lithium composite transition metal oxide.

[0213]

[0214] Comparative Example 2

[0215] After mixing 2.5 parts by weight of Co(OH)2 with 100 parts by weight of the lithium composite transition metal oxide manufactured in Example 1, the temperature was increased from 0°C to 700°C at a rate of 5°C / min in an oxidizing atmosphere, and then steam was introduced into the kiln at a rate of 2.0 kg / hour while maintaining the temperature at 700°C for 2 hours in an oxidizing atmosphere, thereby manufacturing a cathode active material having a coating layer including Co formed on the lithium composite transition metal oxide.

[0216]

[0217] Comparative Example 3

[0218] In Example 1, 2.5 parts by weight of Co(OH)2 was mixed with 100 parts by weight of the lithium composite transition metal oxide manufactured, and then steam was introduced into the kiln at a rate of 2.0 kg / hour and the temperature was increased from 0°C to 500°C at a rate of 5°C / minute in an oxidizing atmosphere. Then, the steam introduction was stopped and the temperature was increased from 500°C to 700°C at a rate of 5°C / minute in an oxidizing atmosphere. Then, steam was introduced into the kiln at a rate of 2.0 kg / hour and the temperature was maintained at 700°C for 2 hours in an oxidizing atmosphere, thereby manufacturing a cathode active material having a coating layer including Co formed on the lithium composite transition metal oxide.

[0219]

[0220] Experimental example

[0221] Experimental Example 1: Evaluation of Residual Lithium

[0222] In order to confirm the quality of the positive electrode active materials manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, the content of residual lithium present on the surface of the positive electrode active materials was measured.

[0223] Specifically, pH titration was performed to measure the content of residual lithium present on the surface of the positive electrode active materials manufactured in Examples 1 to 3 and Comparative Examples 1 to 3. A Metrohm pH meter was used, and the pH was recorded by titrating 1 mL at a time. Specifically, 5 g of the positive electrode active material powder manufactured in Examples 1 to 3 and Comparative Examples 1 to 3 and 100 mL of distilled water were stirred. The pH was titrated while adding a 1 N HCl solution to the solution, and the Li2CO3 and LiOH contents were derived, and the results are shown in Table 1 below.

[0224] Li2CO3(wt%)LiOH(wt%)Total amount of residual lithium (Li2CO3+LiOH)(wt%)Example 10.130.080.21Example 20.130.10.24Example 30.130.070.19Comparative Example 10.250.140.39Comparative Example 20.290.260.55Comparative Example 30.340.250.59

[0225] Through Table 1, it can be confirmed that the amount of by-products existing in the form of Li2Co3 and LiOH on the surface of the positive electrode active material manufactured in Examples 1 to 3, which include a section where steam is injected only in the heating section, is lower than the amount of by-products (total of residual lithium) existing on the surface of the positive electrode active material manufactured in Comparative Example 1, which does not include a section where steam is injected during the heating section and the holding section, the positive electrode active material manufactured in Comparative Example 2, which includes a section where steam is injected during the holding section, and the positive electrode active material manufactured in Comparative Example 3, which includes a section where steam is injected during the heating section and the holding section.

[0226]

[0227] Experimental Example 2: Evaluation of Coating Efficiency

[0228] EPMA mapping images of each of the positive electrode active materials manufactured in Examples 1 to 3 and Comparative Example 1 are sequentially shown in Figures 1 to 4 below.

[0229] Specifically, EPMA is a technique for determining the concentration and distribution of elements in solid samples by analyzing the emitted X-rays by EDS after bombardment of sample particles by an electron beam, and the distribution of Co in the positive electrode active materials was shown using EPMA (JXA-8350F, -15 kV, 20 nA stage mapping conditions) of the positive electrode active materials manufactured in Examples 1 to 3 and Comparative Example 1. Fig. 1 is an EPMA (ELECTRON PROBE MICROANALYSIS) mapping image of the positive electrode active material manufactured in Example 1, Fig. 2 is an EPMA mapping image of the positive electrode active material manufactured in Example 2, Fig. 3 is an EPMA mapping image of the positive electrode active material manufactured in Example 3, and Fig. 4 is an EPMA mapping image of the positive electrode active material manufactured in Comparative Example 1.

[0230] The portions indicated by arrows in Figures 1 to 4 below are portions where the coating layers containing Co exist in a clumped form. In the case of Comparative Example 1, which does not include a section where steam is injected during the temperature-raising section, it can be confirmed that a large number of coating layers containing Co are clumped together compared to Examples 1 to 3.

[0231] In conclusion, it can be confirmed that when a section in which water vapor is injected only in the temperature-raising section is included, the coating layer is formed thinly and uniformly, the concentration deviation of the coating element on the positive electrode active material is reduced, and the coating efficiency is improved.

[0232]

[0233] Experimental Example 3: Moisture content evaluation

[0234] In order to measure the moisture content present in the powders manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, a heating type moisture meter (MX-50, AND) was used to measure the moisture content of each of the powders manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, and the results are shown in Table 2 below.

[0235] Specifically, lithium composite transition metal oxides and coating raw materials were obtained immediately after the steam injection section in Examples 1 to 3 and Comparative Examples 1 to 3, and about 5 g was placed in a sample dish in the device. Then, the lid of the device was closed and the sample dish temperature was set to 130°C, thereby evaporating moisture contained in the lithium composite transition metal oxides and coating raw materials and measuring the degree of mass reduction. At this time, the point in time when the mass no longer decreases is referred to as a completely dried state.

[0236] The moisture content (χ), that is, the percentage difference (moisture content (%)) between the mass (g) of the lithium composite transition metal oxide and the coating raw material immediately after passing through the steam injection section and the mass (g) of the lithium composite transition metal oxide and the coating raw material immediately after passing through the steam injection section and after completely drying the lithium composite transition metal oxide and the coating raw material immediately after passing through the steam injection section, is shown in Table 2 below.

[0237] Meanwhile, in the case of Comparative Example 1 that does not include a section where water vapor is injected, the percentage difference (moisture content (%)) between the mass (g) of the lithium composite transition metal oxide and the coating raw material and the mass (g) after completely drying the lithium composite transition metal oxide and the coating raw material is shown in Table 2 below.

[0238] Functional ratio (%) Example 15.2 Example 21.7 Example 33.5 Comparative example 10.3 Comparative example 210.3 Comparative example 311.7

[0239] Through Table 2, it was confirmed that the moisture content was 1.7% to 5.2% in Examples 1 to 3, including the section where steam was injected only in the temperature-raising section.

[0240] In conclusion, it can be seen that by introducing steam to satisfy the above-mentioned functional ratio, the byproducts present on the surface of the positive electrode active material and the coating raw material reacted appropriately, and the coating became uniform overall.

Claims

1. (A) A step of mixing a positive electrode active material precursor and a lithium (Li)-containing raw material and then calcining to produce a lithium composite transition metal oxide; and (B) a step of mixing the lithium composite transition metal oxide and the coating raw material, and then performing heat treatment to form a coating layer on the lithium composite transition metal oxide; The above heat treatment includes a temperature-raising section for raising the temperature and a maintenance section for maintaining the temperature. A method for manufacturing a cathode active material, comprising a section in which steam is injected only in the above-mentioned temperature-elevating section.

2. In claim 1, A method for manufacturing a cathode active material, wherein the cathode active material precursor has a composition represented by the following chemical formula 1: [Chemical Formula 1] No a Mn b What c M 1 d (OH) 2 In the above chemical formula 1, M 1 is at least one selected from Al, Zr, W, Mg, Ti, Y and B, 0.5≤a<1, 0≤b<0.5, 0≤c<0.5, 0≤d≤0.

1.

3. In claim 1, A method for producing a positive electrode active material, wherein the above-mentioned calcination is performed at a temperature of 700°C to 1,000°C.

4. In claim 1, A method for producing a cathode active material, wherein the lithium composite transition metal oxide has a composition represented by the following chemical formula 2: [Chemical formula 2] Li 1+x1 Ni a1 Mr b1 Co c1 M 2 d1 O 2 In the above chemical formula 2, M 2 is at least one selected from Al, Zr, W, Mg, Ti, Y and B, 0.0≤x1≤0.10, 0.5≤a1<1, 0≤b1<0.5, 0≤c1<0.5, 0≤d1≤0.

1.

5. In claim 1, A method for producing a cathode active material, wherein the lithium composite transition metal oxide is in the form of a single particle.

6. In claim 1, A method for producing a cathode active material without including a washing step.

7. In claim 1, A method for manufacturing a cathode active material, wherein the above coating raw material is a hydroxide containing at least one selected from Co, Al, and Nb.

8. In claim 1, A method for manufacturing a cathode active material, wherein the above coating raw material is cobalt hydroxide.

9. In claim 1, A method for producing a cathode active material, wherein the above coating raw material is mixed in an amount of 0.5 to 5 parts by weight per 100 parts by weight of the lithium composite transition metal oxide.

10. In claim 1, A method for manufacturing a cathode active material, wherein the above heating section includes a section in which steam is introduced at a temperature of 600°C or lower.

11. In claim 1, A method for manufacturing a cathode active material, wherein the above heating section has a heating rate of 1°C / min to 10°C / min.

12. In claim 1, A method for manufacturing a cathode active material, wherein the above-mentioned water vapor is introduced in an amount such that the moisture content (χ) according to the following formula 1 is 1% to 10%: [Formula 1] In the above equation 1, The above α is the mass (g) of the lithium composite transition metal oxide and the coating raw material immediately after passing through the section where water vapor is injected, and the above β is the mass (g) of the lithium composite transition metal oxide and the coating raw material after being completely dried immediately after passing through the section where water vapor is injected.

13. In claim 1, A method for manufacturing a cathode active material, wherein the section in which the above steam is injected is performed under an oxidizing atmosphere.

14. In claim 1, The above maintenance section is a method for manufacturing a cathode active material, wherein heat treatment is performed while maintaining the temperature at 500°C to 900°C.

15. In claim 1, A method for manufacturing a cathode active material, wherein the above maintenance period is performed for 1 to 12 hours.

16. In claim 1, A method for manufacturing a cathode active material, wherein the above maintenance section does not include a section for introducing steam.

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