Precursor for cathode active material, preparation method therefor, cathode active material prepared using same, cathode, and lithium secondary battery

Abstract

The present invention relates to a precursor for a cathode active material and a preparation method therefor, the precursor having a composition represented by chemical formula of Lia[NibCocMndM1 e]Of, wherein the ratio of the sum of the areas of peaks representing Li2CO3 to the sum of the areas of all peaks appearing in an XRD spectrum obtained using X-ray diffraction analysis of the precursor is approximately 0.01-0.15.

Description

Precursor for a positive electrode active material, method for manufacturing the same, positive electrode active material manufactured using the same, positive electrode and lithium secondary battery

[0001] The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0196366 filed on December 24, 2024 and Korean Patent Application No. 10-2025-0205556 filed on December 19, 2025, and all contents disclosed in said Korean patent application documents are incorporated herein as part of the specification.

[0002] The present invention relates to a precursor for a positive electrode active material, a method for manufacturing the precursor, a positive electrode active material manufactured using the same, a positive electrode comprising the positive electrode active material, and a lithium secondary battery.

[0003] Secondary batteries are growing steadily, driven by the expansion of demand sources such as electric vehicles (EVs) and energy storage systems (ESS). Accordingly, continuous efforts are being made to improve the performance and safety of secondary batteries.

[0004] A secondary battery is generally composed of four core components: a positive electrode, a negative electrode, a separator, and an electrolyte. These components interact organically to store and release energy through repeated charging and discharging. For example, electricity is generated as lithium ions move through the electrolyte between the positive and negative electrodes during the charging and discharging process. The positive and negative electrodes determine the performance of the battery, while the electrolyte and separator determine the safety of the secondary battery.

[0005] The present invention provides a precursor for an anode active material and a method for manufacturing the same, wherein the area of ​​the peak representing Li2CO3 in the X-ray diffraction spectrum satisfies specific conditions to produce an anode active material with excellent low-temperature resistance characteristics.

[0006] In addition, the present invention provides a positive active material manufactured using the above-described precursor for a positive active material, a positive electrode comprising the same, and a lithium secondary battery.

[0007] [1] The present invention provides a precursor for a positive electrode active material having a composition represented by the following chemical formula 1, wherein the ratio of the sum of the areas of the peaks representing Li2CO3 to the sum of the areas of all peaks appearing in the XRD spectrum obtained by X-ray diffraction analysis of the precursor is about 0.01 to 0.15.

[0008] [Chemical Formula 1]

[0009] Li a [Ni b Co c Mn d M 1 e ]O f In the above chemical formula 1, M 1 ... comprises one or more selected from the group consisting of Al, Zr, Y, W, Nb, Ti, Ba, and Sr, and 1 <a≤1.08, 0.5≤b<1, 0<c<0.5, 0<d<0.5, 0≤e≤0.2, 2≤f≤2.06이다.

[0010] [2] The present invention provides a precursor for a positive electrode active material, wherein, in [1], the 2 theta (θ) of the peaks representing Li2CO3 in the XRD spectrum appears in regions of approximately 21.3°, 23.5°, 30.4°, 31.7°, 34.0° and 39.8°.

[0011] [3] The present invention provides a precursor for an anode active material according to [1] or [2], wherein in Formula 1, 1.02≤a≤1.06, 0.5≤b≤0.8, 0.05≤c<0.5, and 0.05≤d<0.5.

[0012] [4] The present invention provides a precursor for an anode active material, wherein, in at least one of [1] to [3], the precursor for the anode active material is prepared by spray pyrolysis.

[0013] [5] The present invention provides a precursor for an anode active material in at least one of [1] to [4], wherein the precursor for an anode active material is in the form of secondary particles in which a plurality of primary particles are aggregated, and the primary particles have a polycrystalline structure.

[0014] [6] The present invention provides a precursor for an anode active material in which the precursor for the anode active material has a hollow structure, in at least one of [1] to [5].

[0015] [7] The present invention provides a method for manufacturing a precursor for a positive electrode active material, comprising the steps of: mixing a lithium source, a nickel source, a cobalt source, a manganese source, and a solvent to form a reaction mixture; and spraying the reaction mixture into a high-temperature reactor and pyrolyzing it to form a precursor for a positive electrode active material, wherein the molar ratio of lithium to transition metal in the reaction mixture is greater than about 1:1 and less than or equal to 1.08:1.

[0016] [8] The present invention provides a method for manufacturing a precursor for an anode active material, wherein the lithium source in [7] is lithium metal, lithium carbonate, lithium hydroxide, lithium acetate, lithium oxalate, lithium sulfate, lithium chloride, lithium nitrate, or a combination thereof.

[0017] [9] The present invention provides a method for preparing a precursor for an anode active material, wherein, in [7] or [8], the nickel source is nickel metal, nickel carbonate, nickel hydroxide, nickel acetate, nickel sulfate, nickel chloride, nickel nitrate, nickel pig iron (NPI), mixed hydroxide precipitate (Ni MHP), or a combination thereof.

[0018]

[0010] The present invention provides a method for preparing a precursor for an anode active material, wherein, in at least one of [7] to [9], the cobalt source is cobalt metal, cobalt carbonate, cobalt hydroxide, cobalt acetate, cobalt sulfate, cobalt chloride, cobalt nitrate, mixed hydroxide precipitate (Ni MHP), or a combination thereof.

[0019]

[0011] The present invention provides a method for preparing a precursor for an anode active material, wherein, in at least one of [7] to

[0010] , the manganese source is manganese metal, aluminum metal, manganese carbonate, manganese hydroxide, manganese acetate, manganese sulfate, manganese chloride, manganese nitrate, mixed hydroxide precipitate (Ni MHP), or a combination thereof.

[0020]

[0012] The present invention provides a method for preparing a precursor for an anode active material, wherein, in at least one of [7] to

[0011] , the solvent is sulfuric acid, nitric acid, acetic acid, carbonic acid, or a combination thereof.

[0021]

[0013] The present invention provides a method for manufacturing a precursor for an anode active material, wherein, in at least one of [7] to

[0012] , the pyrolysis is performed in a temperature range of about 600°C to 900°C.

[0022]

[0014] The present invention provides a positive active material comprising a calcined body of at least one of the precursors for a positive active material [1] to [6].

[0023]

[0015] The present invention provides a positive electrode active material, wherein the positive electrode active material comprises a lithium nickel-based oxide having a composition represented by the following [Chemical Formula 2].

[0024] [Chemical Formula 2]

[0025] Li a' [Ni b'Co c' Mn d' M 2 e' ]O2

[0026] In the above chemical formula 2, M 2 comprises one or more selected from the group consisting of Al, Zr, Y, W, Nb, Ti, Ba, and Sr, and 0.8≤a'≤1.08, 0.5≤b'<1, 0 <c'<0.5, 0<d'<0.5, 0≤e'≤0.2이다.

[0027]

[0016] The present invention provides a positive electrode active material, wherein, in

[0014] or

[0015] , the positive electrode active material comprises a single-particle lithium nickel-based oxide having 50 or fewer nodules.

[0028]

[0017] The present invention provides a positive electrode comprising a positive electrode active material according to at least one of

[0014] to

[0016] .

[0029]

[0018] The present invention provides a lithium secondary battery comprising a positive electrode, a negative electrode, and an electrolyte according to

[0017] .

[0030] The precursor for a positive electrode active material according to the present invention satisfies a ratio of the sum of the areas of lithium carbonate peaks to the sum of the areas of all peaks in the XRD spectrum of approximately 0.01 to 0.15. When the XRD peak characteristics of the precursor satisfy the above condition, the effect of improving the low-temperature resistance characteristics of the positive electrode active material manufactured by calcination can be obtained. The low-temperature resistance characteristics of the positive electrode active material vary depending on the proportion of lithium carbonate in the precursor. For example, the lithium carbonate present in the precursor acts as a lithium source during the calcination process, increasing the lithium ratio to the transition metal, and consequently, the cation mixing ratio decreases, thereby improving resistance.

[0031] The precursor for the cathode active material according to the present invention can be manufactured by spray pyrolysis. When the precursor is manufactured through spray pyrolysis, the process is simpler and the manufacturing time is shorter compared to the conventional co-precipitation method, which is mainly used, resulting in a high production yield per unit time and a reduction in the production cost of the precursor.

[0032] A method for manufacturing a precursor for an anode active material according to one embodiment of the present invention involves mixing a lithium source and a transition metal source together during the preparation of a reaction mixture, and then manufacturing the precursor through spray pyrolysis. Since the precursor manufactured by the above method is formed in the form of a lithium metal oxide, the process is simplified because the anode active material can be manufactured by calcining the precursor itself, unlike the conventional method in which the precursor and the lithium source were mixed and then calcined. Furthermore, according to the method of the present invention, the time required for manufacturing the precursor can be shortened because a long co-precipitation reaction is not required.

[0033] A method for manufacturing a precursor according to the present invention satisfies a specific range for the molar ratio of lithium to transition metal in a reaction mixture, thereby providing a positive electrode active material (Li a [Ni b Co c Mn d M 1 e ]O f ) It is possible to produce a precursor in which the ratio of the sum of the areas of the lithium carbonate (Li2CO3) peaks to the sum of the areas of the total peaks in the XRD spectrum of the precursor is about 0.01 to 0.15.

[0034] Anode active material (Li) according to the present invention a [Ni b Co c Mn d M 1 e ]O fA precursor is prepared by calcining a precursor in which the ratio of the sum of the areas of the lithium carbonate (Li2CO3) peaks to the sum of the areas of the total peaks in the XRD spectrum of the precursor is approximately 0.01 to 0.15. The cathode active material prepared using such a precursor exhibits excellent lithium ion mobility at low temperatures. Therefore, by applying this, a lithium secondary battery with excellent low-temperature resistance characteristics can be manufactured.

[0035] The following drawings attached to this specification illustrate embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0036] FIG. 1 illustrates a method for manufacturing a positive electrode active material according to one embodiment of the present invention.

[0037] FIG. 2 is a diagram showing the structure of a positive electrode manufactured using a precursor for a positive electrode active material according to one embodiment of the present invention.

[0038] FIG. 3 is a diagram showing the structure of a secondary battery manufactured by applying a positive electrode manufactured using a precursor for a positive electrode active material according to one embodiment of the present invention.

[0039] Figure 4 shows the XRD spectrum of the precursor prepared according to Example 2.

[0040] In parts of the attached drawings, corresponding components are given the same reference numerals. Those skilled in the art understand that the drawings are intended to illustrate elements simply and clearly and are not necessarily drawn to scale. For example, to aid in understanding various embodiments, the dimensions of some elements depicted in the drawings may be exaggerated compared to others. Additionally, elements of known technology that are useful or essential in commercially viable embodiments may often be omitted so as not to hinder the spirit of the various embodiments of the present invention.

[0041] Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0042] In the present invention, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0043] In the present invention, "single particle type" refers to a particle composed of 50 or fewer nodules, and is a concept that includes a single particle composed of one nodule and a pseudo-single particle which is a complex of 2 to 50 nodules.

[0044] The above “nodule” is a sub-grain unit constituting a single particle and a pseudo-single particle, and may be a single crystal that does not have crystalline grain boundaries, or a polycrystalline one in which no grain boundaries appear to exist when observed at a field of view of 5,000 to 20,000 times using a scanning electron microscope.

[0045] In the present invention, "secondary particle" refers to a particle formed by the aggregation of a plurality of primary particles, for example, tens to hundreds of primary particles. Specifically, the secondary particle may be an aggregate of more than 50 primary particles.

[0046] In the present invention, the term “particle” is a concept that includes any one or all of a single particle, a pseudo-single particle, a primary particle, a nodule, and a secondary particle.

[0047] In the present invention, the average particle size (Dmean) of nodules or primary particles refers to the arithmetic mean value calculated after measuring the particle sizes of nodules or primary particles observed in scanning electron microscope images.

[0048] In the present invention, "average particle size D50" refers to a particle size corresponding to 50% of the volume cumulative amount of the volume cumulative particle size distribution of the powder to be measured, and can be measured using a laser diffraction method. For example, the powder to be measured can be measured by dispersing it in a dispersion medium, introducing it into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), irradiating it with ultrasound of about 28 kHz at an output of 60 W, obtaining a volume cumulative particle size distribution graph, and then determining the particle size corresponding to 50% of the volume cumulative amount.

[0049] As used herein, “about,” “approximately,” and “substantially” are used to mean a range of values ​​or degrees or approximations thereof, taking into account inherent manufacturing and material tolerances (e.g., ±5%).

[0050] Viewing the performance of a secondary battery from two perspectives, the positive electrode is primarily composed of lithium oxide and determines the battery's capacity and performance, while the negative electrode is primarily composed of graphite and significantly affects the battery's lifespan. Meanwhile, the positive and negative electrodes of a secondary battery are manufactured using positive and negative active materials, respectively.

[0051] In the preparation of precursors for cathode active materials, a method involving the introduction of a metal solution containing transition metal elements, an aqueous alkaline solution, and a chelating agent into a reactor to perform a co-precipitation reaction was primarily used. However, the co-precipitation method, which was mainly used for precursor synthesis, required a long time for precursor particle growth and necessitated post-processing steps such as filtration, drying, and washing after the reaction. Furthermore, to manufacture cathode active materials, a calcination process had to be performed after mixing the precursor and the lithium source. Thus, manufacturing cathode active materials via the co-precipitation method required a complex, multi-stage process and resulted in high manufacturing costs due to high energy consumption.

[0052] Recently, methods for synthesizing precursors for cathode active materials using spray pyrolysis have been attempted. Spray pyrolysis is a method in which a solution containing a dissolved precursor is sprayed into droplets ranging in size from a few micrometers to tens of micrometers, and then heated to evaporate the solvent to produce the particles. When producing precursors for cathode active materials via spray pyrolysis, there are advantages such as the elimination of post-processing steps like filtration and washing, reduced manufacturing time, and the ability to produce precursors at a relatively lower cost compared to the co-precipitation method.

[0053] However, since precursors produced by the spray pyrolysis method are difficult to control in terms of particle shape and particle size distribution compared to precursors produced by the co-precipitation method, there was a problem in that when manufacturing cathode active materials using these precursors, physical properties such as resistance, capacity, and lifespan were inferior to those of cathode active materials manufactured using precursors produced by the co-precipitation method.

[0054] Considering these points, the present invention provides a precursor capable of producing a positive electrode active material with excellent physical properties, while having low manufacturing costs and a simple process.

[0055] The present invention will be described in detail below.

[0056] The precursor for a positive electrode active material, the method for manufacturing the precursor for a positive electrode active material, the positive electrode active material, and the positive electrode and / or lithium secondary battery according to the present invention comprise at least one of the configurations disclosed below and may comprise any combination of technically feasible configurations among the configurations below.

[0057]

[0058] Precursor for positive electrode active material

[0059] First, a precursor for a positive electrode active material according to the present invention will be described.

[0060] The precursor for a positive electrode active material according to the present invention is a lithium metal oxide having a composition represented by the following chemical formula 1.

[0061] [Chemical Formula 1]

[0062] Li a [Ni b Co c Mn d M 1 e ]O f

[0063] In the above chemical formula 1,

[0064] M 1 It may include one or more selected from the group consisting of Al, Zr, Y, W, Nb, Ti, Ba, and Sr, and according to one embodiment, it may include one or more selected from Zr, Y, W, Al, and Sr. The M 1 If the element is included, improved effects can be obtained in terms of high-temperature life, resistance, and / or gas generation.

[0065] The above "a" represents the molar ratio of Li to the total moles of metals excluding Li in the precursor, 1 <a≤1.08, 1.01≤a≤1.07, 또는 1.02≤a≤1.6일 수 있다. "a"가 상기 범위를 만족하는 전구체를 이용하여 양극 활물질을 제조할 경우, 층상 구조(layered structure)가 잘 형성되어 리튬 이동성이 우수하게 나타난다. 층상 구조가 잘 형성되기 위해서는 리튬 : 전이금속의 몰비가 1:1 수준이 되어야 하는데, 양극 활물질 제조를 위한 소성 과정에서 전구체에 포함된 리튬의 손실이 발생한다. 따라서, 본 발명에서는 전구체 내 전이금속의 총 몰수에 대한 리튬의 몰수의 비 "a"가 1을 초과하도록 함으로써, 리튬 이동성이 우수한 양극 활물질을 제조할 수 있도록 하였다. 한편, 전이금속의 총 몰수에 대한 리튬의 몰비가 1.08를 초과하지 않도록 함으로써 잔류 리튬량을 적절한 선에서 조절함으로써 용량, 저온 저항, 가스 발생 특성이 우수한 양극 활물질을 제조하였다.

[0066] The above "b" represents the molar ratio of Ni among the metals excluding lithium in the precursor, and may be 0.5≤b<1, 0.5≤b≤0.8, or 0.5≤b≤0.75.

[0067] The above "c" represents the molar ratio of Co among the metals excluding lithium in the precursor, 0 <c<0.5, 0.05≤c<0.5 또는 0.05≤c≤0.3일 수 있다.

[0068] The above "d" is the molar ratio of the Mn element among the metals excluding lithium in the precursor, 0 <d<0.5, 0.05≤d<0.5 또는 0.1≤d≤0.4일 수 있다.

[0069] The above "e" is M among the metals excluding lithium in the precursor. 1 The molar ratio of the elements can be 0≤e≤0.2, 0≤e≤0.15, or 0≤e≤0.10.

[0070] The above "f" is the molar ratio of oxygen to the total moles of metals excluding lithium in the precursor, and may be 2≤f≤2.06, 2≤f≤2.04, or 2≤f≤2.02.

[0071] Unlike hydroxide-type precursors prepared through co-precipitation reactions, the precursor according to the present invention, which is in the form of a lithium metal oxide, contains lithium elements within the precursor; therefore, a positive electrode active material can be manufactured by calcining the precursor without mixing a separate lithium source. Consequently, a positive electrode active material can be manufactured through a simpler process compared to conventional methods. Furthermore, the precursor according to the present invention has the additional advantage of not requiring wastewater treatment because it does not require the washing and drying processes required for hydroxide-type precursors.

[0072]

[0073] When synthesizing a precursor having the composition represented by [Chemical Formula 1] above, the lithium introduced mainly forms lithium metal oxides formed by combining with metals such as Ni, Co, and Mn, but some lithium also exists in the form of Li2CO3 formed by combining with anions.

[0074] This invention utilizes the fact that the ratio of Li2CO3 present in the precursor of the cathode active material influences the low-temperature resistance characteristics of the finally formed cathode active material. Although the reason why the low-temperature resistance characteristics of the cathode active material vary depending on the ratio of Li2CO3 in the precursor is not entirely clear, it is presumed that the Li2CO3 present in the precursor acts as a lithium source during the calcination process, increasing the lithium ratio relative to transition metals, and consequently reducing the cation mixing ratio, thereby improving resistance. However, it was found that resistance actually increases when Li2CO3 is present in the precursor above a certain ratio. Furthermore, it was found that gas generation increases when the ratio of Li2CO3 in the precursor increases.

[0075]

[0076] *69 As the content of Li2CO3 in the precursor increases, the peaks representing Li2CO3 in the XRD spectrum appear more strongly. Therefore, the sum of the areas of all peaks appearing in the XRD spectrum (A total The sum of the areas of the peaks representing Li2CO3 for ) (A Li2CO3 The ratio of )(A Li2CO3 / A total ) can be used as a factor representing the ratio of Li2CO3 in the precursor. In this case, the peaks representing the Li2CO3 are peaks that appear in regions where 2 theta (θ) is approximately 21.3°, 23.5°, 30.4°, 31.7°, 34.0°, and 39.8°.

[0077] According to one embodiment of the present invention, the sum of the areas of all peaks appearing in the XRD spectrum obtained by X-ray diffraction analysis of a precursor of a positive electrode active material (A total The sum of the areas of the peaks representing Li2CO3 for ) (A Li2CO3 The ratio of )(A Li2CO3 / A total When ) satisfies approximately 0.01 to 0.15, the low-temperature resistance characteristics of the positive electrode active material were excellent. For example, the above A Li2CO3 / A total It may be about 0.01 to 0.12, or 0.01 to 0.1.

[0078]

[0079] The precursor for a positive electrode active material according to the present invention may be in the form of secondary particles in which a plurality of primary particles are aggregated, and in this case, the primary particles may have a polycrystalline structure. In the case of lithium nickel-based oxides previously used as positive electrode active materials, most of the primary particles have a single-crystal structure, whereas the lithium metal oxide of the present invention manufactured as a precursor has primary particles with a polycrystalline structure.

[0080] In addition, the precursor for the positive electrode active material according to the present invention may have a hollow structure.

[0081] The precursor for a positive electrode active material according to the present invention has a relatively high porosity compared to lithium metal oxides conventionally used as positive electrode active materials. If the precursor has a hollow structure or high porosity, it has the advantages of improved reactivity with lithium and lowered density, making it easy to grind.

[0082] The precursor for the anode active material of the present invention as described above can be manufactured by spray pyrolysis.

[0083] Referring to FIG. 1, a method for manufacturing a precursor for a positive electrode active material according to the present invention comprises: (1) a step of preparing a reaction mixture by mixing a lithium source, a nickel source, a cobalt source, a manganese source, and a solvent (S10); and (2) a step of forming a precursor for a positive electrode active material by spraying the reaction mixture into a high-temperature reactor and thermally decomposing it (S20).

[0084] First, a lithium source, a nickel source, a cobalt source, a manganese source, and a solvent are mixed to form a reaction mixture (S10).

[0085] The above lithium source may be lithium metal, lithium carbonate, lithium hydroxide, lithium acetate, lithium oxalate, lithium sulfate, lithium chloride, lithium nitrate, or a combination thereof.

[0086] The above nickel source may be nickel metal, nickel carbonate, nickel hydroxide, nickel acetate, nickel sulfate, nickel chloride, nickel nitrate, nickel pig iron (NPI), mixed hydroxide precipitate (Ni MHP), or a combination thereof.

[0087] The above cobalt source may be cobalt metal, cobalt carbonate, cobalt hydroxide, cobalt acetate, cobalt sulfate, cobalt chloride, cobalt nitrate, mixed hydroxide precipitate (Ni MHP), or a combination thereof.

[0088] The above manganese source may be manganese metal, manganese carbonate, manganese hydroxide, manganese acetate, manganese sulfate, manganese chloride, manganese nitrate, mixed hydroxide precipitate (Ni MHP), or a combination thereof.

[0089] The above solvent may be sulfuric acid, nitric acid, acetic acid, carbonic acid, or a combination thereof.

[0090] Meanwhile, in the above reaction mixture, M as needed 1 Further sources may be included. The above M 1 The source is, M 1 Metal element, M 1 It may be an element-containing carbonate, hydroxide, acetate, sulfate, chloride, nitrate, mixed hydroxide precipitate (Ni MHP), or a combination thereof.

[0091] The molar ratio of lithium to transition metal in the above reaction mixture may be about 1:1 to 1.08:1, for example, about 1:1 to 1.07:1, or about 1:1 to 1.06:1.

[0092] The molar ratio of Ni : Co : Mn in the above reaction mixture can be appropriately adjusted considering the composition of the precursor to be prepared.

[0093] The above reaction mixture comprises a lithium source, nickel source, cobalt source, and manganese source in a solvent, optionally M 1 It can be manufactured by adding a sauce and homogenizing it through stirring, etc.

[0094]

[0095] When the reaction mixture is prepared, the reaction mixture is introduced into a spray pyrolysis device, sprayed into a high-temperature reactor, and pyrolyzed to form precursor particles (S20). The spray pyrolysis device may, for example, be equipped with a nozzle for spraying droplets and a high-temperature reactor connected to the nozzle.

[0096] The above spraying can be performed through a spray nozzle provided in a spray pyrolysis device.

[0097] The above spraying can be performed at a pressure of, for example, about 0.01 to 0.5 MPa, 0.01 to 0.3 MPa, or 0.05 to 0.2 MPa. When the spraying pressure satisfies the above range, the particle size of the precursor is appropriately formed, and a precursor with a hollow structure can be obtained. When the precursor is formed with a hollow structure, the specific surface area is high, reactivity with lithium is improved, and the density is low, making it easy to grind.

[0098] The above pyrolysis can be performed in a temperature range of about 600°C to 900°C, for example, about 700°C to 800°C. When the pyrolysis temperature satisfies the above range, the solvent in the spray droplet is dried and the moisture evaporates, and a precursor with a hollow structure can be easily formed.

[0099] Meanwhile, after forming the precursor, the prepared precursor powder can be loaded into an XRD instrument as needed, and an XRD spectrum can be obtained by performing X-ray diffraction analysis under appropriate conditions. In addition, the sum of the areas of all peaks (A) from the XRD spectrum total) The sum of the areas of the peaks exhibited by Li2CO3 for (A Li2CO3) Of A Li2CO3 / A total You can obtain .

[0100]

[0101] positive electrode active material

[0102] Next, referring to FIG. 1, the positive electrode active material according to the present invention will be described.

[0103] The positive electrode active material according to the present invention comprises a calcined body of the precursor for the positive electrode active material according to the present invention described above. The positive electrode active material according to the present invention can be manufactured by calcining the precursor for the positive electrode active material according to the present invention described above at a temperature of about 800°C to 1,000°C (S30). The calcination may be performed in a single step or in multiple steps. For example, the calcination may be performed once at a temperature of about 900°C to 1,000°C, for example, about 920°C to 980°C, or it may be performed a second time at a temperature of about 900°C to 1,000°C after a first calcination at a temperature of about 800°C to 900°C. When the calcination is performed in multiple steps, there is an advantage that sufficient heat can be supplied at a temperature where crystallization occurs stably, thereby increasing the primary particle size and crystallinity.

[0104]

[0105] The positive electrode active material according to the present invention may include a lithium nickel-based oxide.

[0106] The above lithium nickel-based oxide may have a composition represented by the following [Chemical Formula 2].

[0107] [Chemical Formula 2]

[0108] Li a' [Ni b' Co c' Mn d' M 2 e' ]O2

[0109] In the above chemical formula 2, M 2 It may include one or more selected from Al, Zr, Y, W, Nb, Ti, Ba, and Sr.

[0110] The above "a'" represents the molar ratio of lithium to the total molar amount of metals excluding lithium in the lithium nickel-based oxide, and may be 0.8≤a'≤1.2, 0.9≤a'≤1.1, or 0.95≤a'≤1.1.

[0111] The above "b'" represents the molar ratio of Ni among the total metals excluding lithium in the lithium nickel-based oxide, and may be 0.5≤b'<1, 0.5≤b'≤0.8, or 0.5≤b'≤0.75.

[0112] The above "c'" represents the molar ratio of Co among the metals excluding lithium in the lithium nickel-based oxide, 0 <c'<0.5, 0.05≤c'<0.5 또는 0.05≤c'≤0.3일 수 있다.

[0113] The above "d'" is the molar ratio of Mn among the metals excluding lithium in the lithium nickel-based oxide, 0 <d'<0.5, 0.05≤d'<0.5 또는 0.1≤d'≤0.4일 수 있다.

[0114] The above "e'" is M among the metals excluding lithium in lithium nickel-based oxides. 2 The molar ratio of the element can be 0≤e'≤0.2, 0≤e'≤0.15, or 0≤e'≤0.10.

[0115] According to one embodiment, the lithium nickel-based oxide may be a lithium complex transition metal oxide containing about 50 mol% or more of nickel among the total metals excluding lithium, for example, 50 mol% to 80 mol%, or about 50 mol% to 70 mol%.

[0116] The form of the lithium nickel-based oxide is not particularly limited and, depending on one embodiment, may be in the form of secondary particles in which more than 50 primary particles are aggregated, or in the form of single particles containing 50 or fewer nodules. In this case, the primary particles may have a single-crystal structure. If necessary, a positive electrode active material comprising a secondary particle-type lithium nickel-based oxide and a positive electrode active material comprising a single particle-type lithium nickel-based oxide may be mixed and used. In the case of a positive electrode active material comprising a secondary particle-type lithium nickel-based oxide, resistance and capacity characteristics are excellent, and in the case of a positive electrode active material comprising a single particle-type lithium nickel-based oxide, high temperature / high voltage stability and lifespan characteristics are excellent. Therefore, a lithium nickel-based oxide of an appropriate form can be selected and used considering the performance and specifications of the lithium secondary battery to be manufactured.

[0117] According to one embodiment, the lithium nickel-based oxide may be a single-particle lithium nickel-based oxide containing 50 or fewer nodules.

[0118] In the case of single-particle lithium nickel-based oxides, compared to secondary-particle lithium nickel-based oxides, there is less particle breakage due to rolling during cathode manufacturing and excellent structural stability under high temperature and / or high voltage conditions. Therefore, when single-particle lithium nickel-based oxides are applied, cathode degradation is reduced under high temperature and high voltage conditions, and there is less generation of fine particles after cathode manufacturing, resulting in less gas generation due to side reactions between fine particles and the electrolyte. Thus, when single-particle lithium nickel-based oxides are applied, it is advantageous for manufacturing lithium secondary batteries with long life characteristics.

[0119] According to one embodiment, the single-particle lithium nickel-based oxide may include 50 or fewer nodules, for example, 30 or fewer, 1 to 25, or 1 to 15 nodules. When the single-particle lithium nickel-based oxide includes nodules within the above range, particle breakage is reduced during electrode manufacturing, and the occurrence of internal cracks due to volume expansion / contraction of nodules during charging and discharging is reduced, thereby improving high-temperature life characteristics and high-temperature storage characteristics.

[0120] According to one embodiment, the nodules may have an average particle size of about 0.8 μm to 4.0 μm, about 0.8 μm to 3 μm, or about 1.0 μm to 3.0 μm. When the average particle size of the nodules satisfies the above range, particle breakage during electrode manufacturing is minimized, and the increase in resistance can be suppressed more effectively. At this time, the average particle size of the nodules refers to a value obtained by measuring the particle sizes of the nodules observed in the SEM image obtained by analyzing the positive electrode active material powder with a scanning electron microscope, and then calculating the arithmetic mean of the measured values.

[0121]

[0122] The above-described single-particle lithium nickel-based oxide may have a Ni content of about 50 mol% to 80 mol%, about 50 mol% to 75 mol%, or about 50 mol% to 70 mol% among the total metals excluding lithium. In the case of a single-particle lithium nickel-based oxide with a nickel content of 50 mol% to 80 mol%, structural stability at high voltage is high, so the degradation of lifespan characteristics during high-voltage operation can be minimized. In the present invention, by applying a lithium nickel-based oxide with a low Ni content of 80 mol% or less, the degradation of lifespan due to active material degradation during high-voltage operation is suppressed. However, since capacity characteristics deteriorate if the Ni content is too low, the Ni content of the above-described lithium nickel-based oxide was maintained at about 50 mol% or more.

[0123]

[0124] Meanwhile, the cathode active material according to the present invention may further include a coating layer on the surface of the lithium nickel-based oxide. The coating layer may include one or more elements selected from Co, Al, W, Ti, Mg, Zr, Y, Ba, Ca, Sr, Ta, Nb, P, B, and Mo. When a coating layer is formed on the surface of the lithium nickel-based oxide, effects such as improved surface resistance characteristics, prevention of aggregation during the preparation of the cathode slurry, and reduction of gas generation through a reduction in the contact area with the electrolyte can be obtained. According to one embodiment, the coating layer may include Co, Al, Nb, Ti, B, or a combination thereof.

[0125]

[0126] The positive active material according to the present invention is D 50 This can be about 2.0 µm to 20.0 µm, for example, about 2.0 µm to 15.0 µm or about 3.0 µm to 10.0 µm. D of the cathode active material 50 When manufacturing electrodes within the above range, processability and electrolyte impregnation are excellent, resistance is reduced, and output characteristics are improved.

[0127]

[0128] anode

[0129] Next, referring to FIG. 2, the anode according to the present invention will be described.

[0130] The anode (10) according to the present invention comprises the aforementioned anode active material. For example, the anode (10) according to one embodiment of the present invention may comprise an anode current collector (12) and an anode composite layer (14) comprising the aforementioned anode active material.

[0131] Various positive current collectors used in the relevant technical field may be used as the positive current collector (12). For example, the positive current collector (12) may be stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. The positive current collector (12) may typically have a thickness of about 3 μm to 500 μm, and fine irregularities may be formed on the surface of the positive current collector (12) to increase the adhesion of the positive active material. The positive current collector (12) may be used in various forms, such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0132] The anode composite layer (14) may be located on the anode current collector (12) and may be located on one or both sides of the anode current collector (12). The anode composite layer (14) may be a single layer or a multilayer structure of two or more layers.

[0133] The above anode composite layer (14) may include the anode active material, anode conductive material, and anode binder of the present invention.

[0134] At this time, since the above-mentioned positive active material is identical to the positive active material according to the present invention described above, further explanation is omitted.

[0135] According to one embodiment, the positive active material may be included in an amount of about 90% to 99% by weight, for example, about 92% to 98% by weight, or about 94% to 98% by weight, based on the total weight of the positive composite layer (14). If the above range is satisfied, the energy density and capacity characteristics of the lithium secondary battery to which the positive is applied can be improved.

[0136] The above-mentioned positive electrode conductive material is used to impart conductivity to the electrode, and in the battery being constructed, any material that possesses electronic conductivity without causing chemical changes can be used without special limitations. 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, thermal black, carbon fiber, carbon nanotube; metal powder or metal fiber such as copper, nickel, aluminum, or 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 one of these alone or a mixture of two or more may be used. The above-mentioned positive electrode conductive material may typically be included in an amount of about 0.1% to 10% by weight, for example, about 0.1% to 8% by weight, or about 0.1% to 5% by weight, based on the total weight of the positive electrode composite layer.

[0137] The above-mentioned anode binder serves to improve adhesion between anode material particles and adhesion between the anode material and the anode current collector. For example, the above-mentioned anode binder may be a fluoropolymer-based binder comprising polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE); a rubber-based binder comprising styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber, or styrene-isoprene rubber; a cellulose-based binder comprising carboxyl methyl cellulose (CMC), starch, hydroxypropyl cellulose, or regenerated cellulose; a polyalcohol-based binder comprising polyvinyl alcohol; a polyolefin-based binder comprising polyethylene or polypropylene; a polyimide-based binder; or a polyester-based binder. Examples include silane-based binders, and one of these alone or a mixture of two or more may be used. The anode binder may be included in an amount of about 1% to 10% by weight, for example, about 0.5% to 10% by weight, or about 1% to 8% by weight, based on the total weight of the anode composite layer.

[0138] The anode (10) may be manufactured by a method known in the art. For example, the anode (10) may be manufactured by mixing an anode active material, an anode binder, and an anode conductive material in a solvent to prepare an anode slurry, applying the anode slurry onto an anode current collector, and then drying and rolling, or by casting the anode slurry onto a separate support and then laminating the film obtained by peeling it off from the support onto an anode current collector. At this time, the solvent of the anode slurry may be an anode slurry solvent generally used in the art, for example, dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, water, or a mixture thereof, but is not limited thereto. The solvent may be used in an amount that dissolves or disperses the anode active material, the anode conductive material, and the anode binder, and has a viscosity such that the cathode slurry can be uniformly coated.

[0139]

[0140] lithium secondary battery

[0141] Next, referring to FIG. 3, a lithium secondary battery according to an embodiment of the present invention will be described. A lithium secondary battery (100) according to an embodiment of the present invention comprises a positive electrode (10) according to the present invention; a negative electrode (20) disposed opposite to the positive electrode (10); and an electrolyte (40). Optionally, the lithium secondary battery (100) according to the present invention may further comprise a separator (30) interposed between the positive electrode (10) and the negative electrode (20).

[0142] Additionally, a lithium secondary battery (100) according to one embodiment of the present invention includes an electrode assembly comprising a positive electrode (10), a negative electrode (20), and a separator (30), and a battery case (50) that accommodates an electrolyte (40).

[0143] (1) positive electrode

[0144] Since the anode (10) above is the same as described above, the remaining components excluding the anode (10) will be described below.

[0145]

[0146] (2) Cathode

[0147] In a lithium secondary battery (100) according to the present invention, the negative electrode (20) may include a negative electrode composite layer comprising a negative electrode active material, a negative electrode current collector, and a negative electrode composite layer disposed on at least one surface of the negative electrode current collector.

[0148]

[0149] The above-mentioned negative 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., and aluminum-cadmium alloy may be used. In addition, the above-mentioned negative current collector may typically have a thickness of about 3 μm to 500 μm, and, similar to the positive current collector, fine irregularities may be formed on the surface of the current collector to strengthen the bonding strength of the negative active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0150]

[0151] The above cathode composite layer may be located on the cathode current collector and may be located on one or both sides of the cathode current collector. The above cathode composite layer may have a single-layer structure and may have a multi-layer structure of two or more layers.

[0152] When the cathode composite layer is a multilayer structure composed of two or more layers, the types and / or contents of the cathode active material, cathode binder, and / or cathode conductive material in each layer may differ from one another. By forming the cathode composite layer into a multilayer structure and varying the composition of each layer, the performance characteristics of the battery, such as rapid charging performance and output characteristics, can be appropriately controlled.

[0153] Meanwhile, as the above-mentioned negative electrode active material, a compound capable of reversible intercalation and deintercalation of lithium may be used. For example, as the negative electrode active material, 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 alloys, Sn alloys, or Al alloys; SiO₂ β Examples include metal oxides capable of doping and dedoping lithium, such as (0 < β < 2), SnO2, vanadium oxide, and lithium vanadium oxide; or composites comprising the metal compound and carbonaceous material, such as Si-C composites or Sn-C composites, and any one or more of these may be used.

[0154] Meanwhile, both low-crystallinity carbon and high-crystallinity carbon can be used as the aforementioned carbonaceous materials. Representative examples of low-crystallinity carbon include soft carbon and hard carbon, while representative examples of high-crystallinity carbon include amorphous, plate-like, flake-like, spherical, or fibrous natural or artificial graphite, 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.

[0155] According to one embodiment, the negative electrode active material may be a carbon-based negative electrode active material, wherein the carbon-based negative electrode active material may include, for example, natural graphite, artificial graphite, graphitized carbon fiber, amorphous carbon, soft carbon, hard carbon, or a combination thereof. Alternatively, the carbon-based negative electrode active material may include natural graphite and artificial graphite.

[0156] The above carbon-based negative electrode active material has an average particle size D 50 This can be about 2㎛ to 30㎛, for example, about 5㎛ to 30㎛.

[0157] The above-mentioned cathode active material may be included in an amount of about 80% to 98% by weight, about 90% to 98% by weight, or about 93% to 98% by weight based on the total weight of the cathode composite layer. When the content of the cathode active material satisfies the above range, excellent energy density can be achieved.

[0158]

[0159] Meanwhile, the above-mentioned cathode composite layer may further include a cathode conductive material and / or a cathode binder together with the cathode active material.

[0160] A cathode conductive material is used to impart conductivity to the cathode, and in the battery being constructed, any material that possesses electronic conductivity without causing chemical changes can be used without any special restrictions. Examples of cathode conductive materials include carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, carbon fiber, carbon nanotube; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and one of these alone or a mixture of two or more may be used.

[0161] The above cathode conductive material may typically be included in an amount of about 0.1% to 10% by weight, about 0.1% to 8% by weight, or about 0.1% to 5% by weight based on the total weight of the cathode composite layer.

[0162] The above-mentioned cathode binder serves to improve adhesion between cathode active material particles and adhesion between the cathode active material and the cathode current collector. For example, cathode binders may include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer rubber (EPDM rubber), sulfonated-EPDM, styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one of these alone or a mixture of two or more may be used.

[0163] The above cathode binder may be included in an amount of about 0.1% to 10% by weight, about 0.5% to 10% by weight, or about 1% to 8% by weight based on the total weight of the cathode composite layer.

[0164]

[0165] The above cathode (20) may be manufactured by a method known in the art. For example, the cathode (20) may be manufactured by mixing a cathode active material, a cathode binder, and / or a cathode conductive material in a solvent to produce a cathode slurry, applying the cathode slurry onto a cathode current collector, and then drying and rolling, or by casting the cathode slurry onto a separate support and then laminating the film obtained by peeling off from the support onto a cathode current collector.

[0166] Meanwhile, solvents commonly used in the relevant technical field may be used as the solvent for the cathode slurry, for example, dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, water, or mixtures thereof, but are not limited thereto. The solvent may be used in an amount that dissolves or disperses the cathode active material, cathode conductive material, and cathode binder, and has a viscosity such that the cathode slurry can be uniformly coated.

[0167] (3) Separator

[0168] The above separator physically separates the negative electrode and the positive electrode and provides a pathway for the movement of lithium ions; any separator typically used in lithium secondary batteries can be used without any special restrictions. In this case, the separator may be interposed between the positive electrode and the negative electrode.

[0169] According to one embodiment, a porous polymer film made of a polyolefin-based 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 may be used. In addition, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers, may be used. Furthermore, a coated separator containing a ceramic component or a polymer material may be used to ensure heat resistance or mechanical strength, and may optionally be used in a single-layer or multi-layer structure.

[0170] (4) Electrolyte

[0171] The electrolyte (40) according to the present invention may include a lithium salt and an organic solvent.

[0172] The above lithium salt can be used without special limitations as long as it is a compound capable of providing lithium ions used in a lithium secondary battery (100). For example, the above lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2. According to one embodiment, the concentration of the above lithium salt may be used within a range of about 0.1M to 5.0M or about 0.1M to 3.0M. When the concentration of the lithium salt is within the above range, the electrolyte has appropriate conductivity and viscosity, so it can exhibit excellent electrolyte performance and lithium ions can move effectively.

[0173]

[0174] The above organic solvent may include at least one of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, and a cyclic ester-based organic solvent.

[0175] The above-mentioned cyclic carbonate-based organic solvent is a high-viscosity organic solvent and may include at least one organic solvent selected from ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate.

[0176] In addition, the linear carbonate-based organic solvent is an organic solvent having low viscosity and low dielectric constant, and representative examples may include at least one organic solvent selected from dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate, and ethylpropyl carbonate, and according to one embodiment, may include ethylmethyl carbonate (EMC).

[0177] The above linear ester-based organic solvent may include, for example, at least one organic solvent selected from methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate.

[0178] The above-mentioned cyclic ester-based organic solvent may include at least one organic solvent selected from butyrolactone, valerolactone, and caprolactone.

[0179] According to one embodiment, the electrolyte (40) according to the present invention may include ethylene carbonate and dimethyl carbonate as organic solvents.

[0180]

[0181] Meanwhile, the above electrolyte (40) may additionally include other additives in addition to the above electrolyte components for the purpose of improving the lifespan characteristics of the battery, suppressing the decrease in battery capacity, and improving the discharge capacity of the battery.

[0182] These other additives may include, as representative examples, at least one other additive selected from cyclic carbonate compounds, halogen-substituted carbonate compounds, sulfone compounds, sulfate compounds, borate compounds, nitrile compounds, benzene compounds, amine compounds, silane compounds, and lithium salt compounds different from the lithium salt contained in the electrolyte.

[0183] For example, the above other additives are vinylene carbonate (VC), vinylethylene carbonate, fluoroethylene carbonate (FEC), 1,3-propane sulfone (PS), 1,4-butane sulfone, ethene sulfone, 1,3-propene sulfone (PRS), 1,4-butene sulfone, 1-methyl-1,3-propene sulfone, ethylene sulfate (ESA), trimethylene sulfate (TMS), methyl trimethylene sulfate (MTMS), tetraphenyl borate, lithium oxalyl difluoroborate, succinonitrile, adiponitrile, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, Examples include one or more compounds selected from 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, 4-fluorophenylacetonitrile, fluorobenzene, triethanolamine, ethylenediamine, tetravinylsilane, LiN(SO2F)2 (Lithium bis(fluorosulfonyl)imide, LiFSI), LiN(SO2CF3)2 (lithium bis(trifluoromethane sulfonyl)imide, LiTFSI), LiPO2F2, LiODFB, LiBOB (lithium bis-oxalate toborate (LiB(C2O4)2)) and LiBF4.

[0184] The above other additives may be included in an amount of about 0.01% to 20% by weight based on the total weight of the electrolyte, for example, about 0.05% to 5.0% by weight. At the above range of other additive content, the effects of improving low-temperature output, high-temperature storage characteristics, and high-temperature life characteristics of the battery are excellent, and side reactions within the electrolyte during charging and discharging of the battery can be appropriately suppressed.

[0185]

[0186] (5) Battery case

[0187] A battery case (50) according to one embodiment of the present invention may be manufactured in a prismatic type, pouch type, coin type, and cylindrical type depending on the form in which it is manufactured.

[0188] The lithium secondary battery (100) according to the present invention as described above can be usefully applied to portable devices such as mobile phones, laptop computers, and digital cameras, and to electric vehicle fields such as hybrid electric vehicles (HEV). Since the lithium secondary battery (100) according to the present invention can achieve excellent output characteristics even under low temperature conditions, it can be particularly usefully used in the electric vehicle field.

[0189] According to another embodiment of the present invention, a battery module comprising a lithium secondary battery (100) according to the present invention as a unit cell and a battery pack comprising the same are provided.

[0190] The above battery module or battery pack can be used as a power source for one or more medium-to-large devices, including a power tool; an electric vehicle (EV), a hybrid electric vehicle, and a plug-in hybrid electric vehicle (PHEV); or a power storage system.

[0191]

[0192] The present invention will be explained in more detail below through examples. However, the following examples are intended only to enable a person skilled in the art to fully understand and easily implement the present invention, and the scope of the rights of the present invention is not limited to the following examples.

[0193]

[0194] Example 1

[0195] A reaction mixture was prepared by dissolving lithium nitrate, nickel nitrate, cobalt nitrate, and manganese nitrate in nitric acid in amounts such that the molar ratio of Li : Ni : Co : Mn was 1 : 0.6 : 0.1 : 0.3. In this case, the molar ratio of lithium to transition metal in the reaction mixture was 1:1.

[0196] The above reaction mixture was introduced into a spray pyrolysis apparatus and sprayed into a high-temperature reactor at a temperature of 400°C at a pressure of 0.1 MPa to pyrolyze it at a rate of 1.43 hours per ton. After the pyrolysis was completed, the resulting precursor powder was obtained.

[0197] The obtained precursor powder was first calcined at 860°C for 4 hours, and then calcined at 960°C for 8 hours to prepare an anode active material.

[0198] A positive electrode slurry was prepared by mixing the positive electrode active material, conductive material (carbon black), and PVdF binder prepared as described above in N-methylpyrrolidone in a weight ratio of 95:2:3. The positive electrode slurry was applied onto an aluminum current collector, dried, and rolled to produce a positive electrode.

[0199] An electrode assembly was manufactured by interposing a porous polyethylene separator between the anode and the lithium metal electrode (negative electrode), and then the electrode assembly was inserted into a battery case and an electrolyte was injected to manufacture a coin-half cell.

[0200]

[0201] Example 2

[0202] A precursor powder, a positive electrode active material, a positive electrode, and a coin half cell were prepared in the same manner as in Example 1, except that a reaction mixture was prepared by dissolving lithium nitrate, nickel nitrate, cobalt nitrate, and manganese nitrate in nitric acid in amounts such that the molar ratio of Li:Ni:Co:Mn was 1.02:0.6:0.1:0.3. In this case, the lithium:transition metal molar ratio in the reaction mixture was 1.02:1.

[0203]

[0204] Example 3

[0205] A precursor powder, a positive electrode active material, a positive electrode, and a coin half cell were prepared in the same manner as in Example 1, except that a reaction mixture was prepared by dissolving lithium nitrate, nickel nitrate, cobalt nitrate, and manganese nitrate in nitric acid in amounts such that the molar ratio of Li:Ni:Co:Mn was 1.06:0.6:0.1:0.3. In this case, the lithium:transition metal molar ratio in the reaction mixture was 1.06:1.

[0206]

[0207] Comparative Example 1

[0208] A precursor powder, a positive electrode active material, a positive electrode, and a coin half cell were prepared in the same manner as in Example 1, except that a reaction mixture was prepared by dissolving lithium nitrate, nickel nitrate, cobalt nitrate, and manganese nitrate in nitric acid in amounts such that the molar ratio of Li:Ni:Co:Mn was 0.98:0.6:0.1:0.3. In this case, the molar ratio of lithium to transition metal in the reaction mixture was 0.98:1, and the molar ratio of lithium to transition metal in the reaction mixture is outside the scope of the present invention.

[0209]

[0210] Comparative Example 2

[0211] A precursor powder, a positive electrode active material, a positive electrode, and a coin half cell were prepared in the same manner as in Example 1, except that a reaction mixture was prepared by dissolving lithium nitrate, nickel nitrate, cobalt nitrate, and manganese nitrate in nitric acid in amounts such that the molar ratio of Li:Ni:Co:Mn was 1.1:0.6:0.1:0.3. In this case, the molar ratio of lithium to transition metal in the reaction mixture was 1.1:1, and the molar ratio of lithium to transition metal in the reaction mixture is outside the scope of the present invention.

[0212]

[0213] Experimental Example 1

[0214] The precursor powders prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were loaded onto the powder holder of an XRD instrument (Bruker D8 Endeavor-2) so that the sample surface was evenly distributed, and then X-ray diffraction analysis was performed under the following conditions to obtain XRD spectra.

[0215] The sum of the areas of all peaks from the above XRD spectrum (A total) The sum of the areas of the peaks exhibited by Li2CO3 for (A Li2CO3) Of A Li2CO3 / A total ...was obtained. The measurement results are shown in [Table 1] below. Figure 4 shows the XRD spectrum of the precursor for the cathode active material prepared by the method of Example 2.

[0216] <XRD 측정 조건>

[0217] X-ray: Cu Kα 40kV, 40mA

[0218] Measurement range (2θ): 10° ~ 70°

[0219] Step invrement(2θ) : 0.04°

[0220] Measurement time (time / step): 0.5s

[0221] Meanwhile, referring to Figure 4, the peaks representing Li2CO3 are peaks that appear in regions where 2 theta (θ) is approximately 21.3°, 23.5°, 30.4°, 31.7°, 34.0°, and 39.8°.

[0222] Experimental Example 2: Low-temperature resistance measurement

[0223] Each coin half cell prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was charged to a State of Charge (SOC) of 20, activated, then charged to an SOC of 2, placed in a low-temperature (-10℃) chamber and left for 3 hours, and then continuously discharged at a constant current of 2C for 18 seconds while measuring the voltage drop at low temperature. The resistance (R = ΔV / I) was calculated by dividing the voltage drop (ΔV) from 0 to 18 seconds by the current value (I). The measurement results are shown in Table 1 below.

[0224]

[0225] Experimental Example 3: Initial Dose Measurement

[0226] After forming each of the coin half cells prepared in Examples 1 to 3 and Comparative Examples 1 to 2, they were each charged at 25°C with a constant current of 0.1C until the voltage reached 4.45V, and then discharged with a constant current of 0.1C until the voltage reached 2.5V, and the charging capacity and discharging capacity were measured.

[0227]

[0228] Experimental Example 4: Measurement of Gas Generation Amount

[0229] An electrode assembly was prepared by interposing a separator between each positive and negative electrode prepared in Examples 1 to 3 and Comparative Examples 1 to 2, and a lithium secondary battery was prepared by placing the electrode assembly in a battery case and injecting an electrolyte.

[0230] At this time, the cathode was prepared by adding a cathode active material, a cathode conductive material, and a cathode binder to water in a weight ratio of 95.6:1:3.4 to form a cathode slurry. At this time, artificial graphite and natural graphite were mixed in a weight ratio of 5:5 and used as the cathode active material, carbon black was used as the cathode conductive material, and styrene-butadiene rubber (SBR) and carboxymethylcellulose (CMC) were mixed in a weight ratio of 1.1:2.3 and used as the cathode binder. Then, the cathode slurry was applied onto a copper current collector, and manufactured by drying and rolling.

[0231] After storing the above lithium secondary battery at 60°C for 4 weeks, the amount of gas generated (unit: mL) was measured. The amount of gas generated was calculated by measuring the (weight in air - weight in water) of the lithium secondary battery before and after storage, and the change in the (weight in air - weight in water) before and after storage. The measurement results are shown in Table 1 below.

[0232]

[0233] A Li2CO3 / A total Low-temperature resistance [Ω] Charge capacity [mAh / g] Discharge capacity [mAh / g] Initial efficiency [%] Gas generation amount (mL) Example 1 0.0 1 17 1.2 220 8 200 0.7 9 0.9 0.28 Example 20.0 3 16 2.6 221 5 202 19 1.2 0.3 Example 30.1 16 2.2 221 220 1.9 9 1.3 0.32 Comparative Example 10 220 6 220 9 19 7.68 9.5 0.13 Comparative Example 20 220 7.3 221 6 200 69 0.5 0.75

[0234] Through Table 1 above, A Li2CO3 / A total Examples 1 to 3, which apply a precursor satisfying the scope (0.01-0.15) of the present invention, are A Li2CO3 / A totalIt can be confirmed that the present invention exhibits superior effects in terms of low-temperature resistance, initial efficiency, and gas generation amount compared to Comparative Examples 1 and 2, which applied precursors outside the scope of the present invention. For example, regarding low-temperature resistance, Examples 1, 2, and 3 showed relatively low values ​​of 171.2Ω, 162.6Ω, and 162.2Ω, respectively, whereas Comparative Examples 1 and 2 showed values ​​of 220.6Ω and 207.3Ω, respectively, which are higher values ​​compared to the examples.

[0235] Although the foregoing has been described with reference to the embodiments of the present disclosure, a person skilled in the art or having ordinary knowledge in the art will understand that various modifications and changes can be made to the various embodiments of the present disclosure without departing from the technical scope of the various embodiments of the present disclosure as set forth in the claims below. Accordingly, the technical scope of the various embodiments of the present disclosure should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims.

Claims

A precursor for a positive electrode active material having a composition represented by the following chemical formula 1, and The sum of the areas of all peaks in the XRD spectrum obtained by X-ray diffraction analysis of the above precursor (A total The sum of the areas of the peaks representing Li2CO3 for ) (A Li2CO3 The ratio of )(A Li2CO3 / A total A precursor for a positive electrode active material having a value of 0.01 to 0.

15. [Chemical Formula 1] Li a [Ni b Co c Mr d M 1 e ]O f In the above chemical formula 1, M 1 ... comprises one or more selected from the group consisting of Al, Zr, Y, W, Nb, Ti, Ba, and Sr, and 1 <a≤1.08, 0.5≤b<1, 0<c<0.5, 0<d<0.5, 0≤e≤0.2, 2≤f≤2.06임. In paragraph 1, A precursor for a positive electrode active material, wherein the peaks representing Li2CO3 in the XRD spectrum appear in regions where 2theta (Theta, θ) is 21.3°, 23.5°, 30.4°, 31.7°, 34.0°, and 39.8°. In paragraph 1, A precursor for a positive electrode active material in the above chemical formula 1, wherein 0.9≤a≤1.1, 0.5≤b≤0.8, 0.05≤c<0.5, and 0.05≤d<0.

5. In paragraph 1, The above precursor for the positive electrode active material is in the form of secondary particles formed by the aggregation of multiple primary particles, and The above primary particle is a precursor for an anode active material having a polycrystalline structure. In paragraph 1, The above precursor for a positive electrode active material is a precursor for a positive electrode active material having a hollow structure. In paragraph 1, The above precursor for the positive electrode active material is a precursor for the positive electrode active material that is manufactured by spray pyrolysis. A method for manufacturing a precursor for a positive electrode active material, A step of forming a reaction mixture by mixing a lithium source, a nickel source, a cobalt source, a manganese source, and a solvent; and The above reaction mixture includes the step of spraying into a high-temperature reactor and thermally decomposing it to form a precursor for an anode active material, and A method for preparing a precursor for a positive electrode active material, wherein the lithium:transition metal molar ratio in the above reaction mixture is 1:1 to 1.08:

1. In Paragraph 7, A method for manufacturing a precursor for a positive electrode active material, wherein the lithium source is lithium metal, lithium carbonate, lithium hydroxide, lithium acetate, lithium oxalate, lithium sulfate, lithium chloride, lithium nitrate, or a combination thereof. In Paragraph 7, A method for preparing a precursor for an anode active material, wherein the nickel source is nickel metal, nickel carbonate, nickel hydroxide, nickel acetate, nickel sulfate, nickel chloride, nickel nitrate, nickel pig iron (NPI), mixed hydroxide precipitate (Ni MHP), or a combination thereof. In Paragraph 7, A method for preparing a precursor for an anode active material, wherein the above-mentioned cobalt source is cobalt metal, cobalt carbonate, cobalt hydroxide, cobalt acetate, cobalt sulfate, cobalt chloride, cobalt nitrate, mixed hydroxide precipitate (Ni MHP), or a combination thereof. In Paragraph 7, A method for preparing a precursor for an anode active material, wherein the above manganese source is manganese metal, manganese carbonate, manganese hydroxide, manganese acetate, manganese sulfate, manganese chloride, manganese nitrate, mixed hydroxide precipitate (Ni MHP), or a combination thereof. In Paragraph 7, A method for preparing a precursor for an anode active material, wherein the solvent is sulfuric acid, nitric acid, acetic acid, carbonic acid, or a combination thereof. In Paragraph 7, A method for manufacturing a precursor for an anode active material, wherein the above pyrolysis is performed in a temperature range of 600°C to 900°C. A positive electrode active material comprising a calcined body of a precursor for a positive electrode active material according to any one of claims 1 to 6. In Paragraph 14, The above positive active material is a positive active material comprising a lithium nickel-based oxide having a composition represented by the following [Chemical Formula 2]. [Chemical Formula 2] Li a' [Ni b' Co c' Mr d' M 2 e' ]O2 In the above chemical formula 2, M 2 ... comprises one or more selected from Al, Zr, Y, W, Nb, Ti, Ba, and Sr, and 0.8≤a'≤1.2, 0.5≤b'<1, 0 <c'<0.5, 0<d'<0.5, 0≤e'≤0.2임. In paragraph 15, The above positive active material comprises a single-particle lithium nickel-based oxide containing 50 or fewer nodules. A positive electrode comprising a positive electrode active material according to claim 15. A lithium secondary battery comprising a positive electrode, a negative electrode, and an electrolyte according to claim 17.

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