Positive electrode active material, method for preparing same, positive electrode, and rechargeable lithium battery

Abstract

The invention relates to a positive electrode active material, a method for preparing the same, a positive electrode, and a rechargeable lithium battery. The positive electrode active material includes a layered lithium nickel-based composite oxide in which a nickel content is not less than about 60 mol%, an aluminum content is about 0.8 mol% to about 1.5 mol%, a zirconium content is about 0.1 mol% to about 0.3 mol%, and a ratio of the aluminum content to the zirconium content (Al / Zr) is not less than about 5, based on a total mole of a metal other than lithium of 100 mol% of the layered lithium nickel-based composite oxide. And the positive electrode active material is in the form of a single particle having an average particle diameter (D50) of about 1 [mu] m to about 4 [mu] m.

Description

Technical Field

[0001] One or more embodiments of the present disclosure relate to a positive electrode active material, a method for preparing the same, a positive electrode including the positive electrode active material, and a rechargeable lithium battery including the positive electrode. Background Art

[0002] Portable information devices (such as, cellular phones, laptop computers, smart phones, etc.) and / or electric vehicles have utilized rechargeable lithium batteries having a relatively high energy density and easy portability as a driving power source. Recently, research has been actively conducted to utilize rechargeable lithium batteries having a high energy density as a driving power source for hybrid vehicles or electric vehicles and / or as a power storage source for home energy storage units (e.g., electrical energy storage units or power walls).

[0003] Various positive electrode active materials have been studied to realize rechargeable lithium batteries applied to the above uses. Among them, lithium nickel-based oxides, lithium nickel manganese cobalt composite oxides, lithium nickel cobalt aluminum composite oxides, and lithium cobalt oxides are mostly or mainly used as positive electrode active materials. In recent years, high-nickel positive electrode active materials having a nickel content (e.g., amount) of about 80 mol% or higher have been actively developed (due to their potential high energy density (ability to achieve a high energy density)), but they have various problems or challenges (such as structural degradation due to charge and discharge, surface side reactions with the electrolyte, degradation due to particle breakage, etc.). Accordingly, there is still a need or requirement to develop a positive electrode active material capable of achieving both a high energy density and long cycle life characteristics.

[0004] As a high-nickel positive electrode active material for achieving a relatively high capacity, secondary particles (e.g., each secondary particle) made by aggregating a plurality of primary particles have been mostly or mainly used, but recently, in order to achieve a long cycle life while reducing gas generation, single particles have been evaluated or studied. However, since single particles are manufactured by increasing the firing temperature, there is a problem of increasing particle aggregation and deteriorating productivity. In order to prevent or reduce particle aggregation and lower the firing temperature, research has been proposed to add an alkaline grain growth promoter during the synthesis of single particles, but there is a problem that the alkaline grain growth promoter may remain in the positive electrode after firing and act as a resistance, resulting in deterioration of the cycle life of the rechargeable lithium battery using such a high-nickel positive electrode active material. In addition, a rinsing process for removing the residual alkaline grain growth promoter or residual salts can be introduced, but this brings another problem of increasing the manufacturing cost or complicating the process. Summary of the Invention

[0005] One or more aspects of the present disclosure relate to methods for effectively preparing a high-nickel-based positive electrode active material in the form of single particles without using an alkaline grain growth promoter at a relatively low firing temperature, and methods for reducing aggregation between particles and simplifying and economizing the overall preparation process. Accordingly, a positive electrode active material that is structurally stable and free of residual impurities is provided, thereby not increasing resistance and achieving a long cycle life.

[0006] In one or more embodiments, the positive electrode active material includes a layered lithium nickel-based composite oxide, wherein, based on the total moles of metals other than lithium of 100 mol% of the layered lithium nickel-based composite oxide, the nickel content (e.g., amount) is greater than or equal to about 60 mol%, the aluminum content (e.g., amount) is about 0.8 mol% to about 1.5 mol%, and the zirconium content (e.g., amount) is about 0.1 mol% to about 0.3 mol%, the ratio (Al / Zr) of the aluminum content (e.g., amount) to the zirconium content (e.g., amount) is greater than or equal to about 5, and the positive electrode active material is in the form of single particles (e.g., single particles or monolithic particles) having an average particle diameter (D 50 ) of about 1 μm to about 4 μm.

[0007] In one or more embodiments, the method for preparing the positive electrode active material includes: performing a coprecipitation reaction of a nickel precursor and an M 1 precursor to prepare a nickel-based composite hydroxide in the form of particles and having micropores inside the particles; mixing the nickel-based composite hydroxide, a lithium raw material, an aluminum raw material, and a zirconium raw material and performing a heat treatment to prepare a hollow secondary particle including a layered lithium nickel-based composite oxide and having pores inside, as a secondary particle formed by aggregating a plurality of primary particles; pulverizing the secondary particle; and obtaining the positive electrode active material, wherein M 1 is one or more elements selected from boron (B), barium (Ba), calcium (Ca), cerium (Ce), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), niobium (Nb), silicon (Si), tin (Sn), strontium (Sr), titanium (Ti), vanadium (V), tungsten (W), and zinc (Zn), based on the total moles of 100 mol% of the metal of the nickel-based composite hydroxide, the aluminum of the aluminum raw material, and the zirconium of the zirconium raw material, the aluminum content (e.g., amount) of the aluminum raw material is about 0.8 mol% to about 1.5 mol% and the zirconium content (e.g., amount) of the zirconium raw material is about 0.1 mol% to about 0.3 mol%, and the ratio (Al / Zr) of the aluminum content (e.g., amount) to the zirconium content (e.g., amount) is greater than or equal to about 5.

[0008] Some embodiments provide a positive electrode for a rechargeable lithium battery, which includes the aforementioned positive electrode active material.

[0009] Some embodiments provide a rechargeable lithium battery including a positive electrode, a negative electrode, and an electrolyte.

[0010] According to one or more embodiments, a high-nickel type positive electrode active material in the form of single particles can be synthesized in a simple manner at a relatively low heat treatment temperature, and since an alkaline grain growth promoter is not used during the synthesis process, there is no residue and the resistance is not increased. The structure of the positive electrode active material is stable, and long cycle life characteristics of the rechargeable lithium battery can be achieved. That is, the high-nickel type positive electrode active material can be easily synthesized into single particles at a relatively low temperature without using an alkaline grain growth promoter. This results in no residue, reduced resistance, stable structure, and improved long-term cycle life of the rechargeable lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figures 1 to 4 Each is a schematic diagram showing a rechargeable lithium battery according to one or more embodiments.

[0012] Figure 5 It is a scanning electron microscope (SEM) image of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Example 1.

[0013] Figure 6 It is an SEM image of the surface of the positive electrode active material in the form of single particles after pulverization prepared in Example 1.

[0014] Figure 7 It is an SEM image of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Example 2.

[0015] Figure 8 It is an SEM image of the surface of the positive electrode active material in the form of single particles after pulverization prepared in Example 2.

[0016] Figure 9 It is an SEM image of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Comparative Example 1.

[0017] Figure 10 It is an SEM image of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Comparative Example 2.

[0018] Figure 11 It is an SEM image of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Example 3.

[0019] Figure 12 It is an SEM image of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Example 4.

[0020] Figure 13 SEM images of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Comparative Example 3.

[0021] Figure 14 SEM images of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Example 5.

[0022] Figure 15 SEM images of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Example 6.

[0023] Figure 16 SEM images of the surface of the positive electrode active material in the form of secondary particles before pulverization prepared in Comparative Example 4.

[0024] Figure 17 Graph showing the cycle life characteristics of the rechargeable lithium battery cells manufactured in Example 1, Example 2, and Comparative Example 1.

[0025] Description of Reference Numerals

[0026] 100: Rechargeable lithium battery 10: Positive electrode

[0027] 11: Positive electrode lead tab 12: Positive electrode terminal

[0028] 20: Negative electrode 21: Negative electrode lead tab

[0029] 22: Negative electrode terminal 30: Separator

[0030] 40: Electrode assembly 50: Case

[0031] 60: Sealing member 70: Electrode tab

[0032] 71: Positive electrode tab 72: Negative electrode tab Detailed Description

[0033] Hereinafter, exemplary embodiments will be described in more detail so that those of ordinary skill in the art can easily implement them. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein.

[0034] The terms used herein are for the purpose of describing embodiments only and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, as used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms. Further, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure".

[0035] As used herein, "a combination thereof" can refer to a mixture of components, a laminate, a composite, a copolymer, an alloy, a blend, a reaction product, etc.

[0036] In this document, it should be understood that terms such as "comprise(s) / comprising", "include(s) / including", or "have(has) / having" are intended to indicate the presence of specified features, quantities, operations (e.g., actions or tasks), elements, and / or combinations thereof (e.g., any suitable combination), but do not preclude the possibility of the presence or addition of one or more other features, quantities, operations, elements, and / or combinations thereof (e.g., any suitable combination).

[0037] In the drawings, for clarity, the thickness of layers, films, panels, regions, etc. may be exaggerated, and the same reference numerals are used throughout to designate the same elements, and their repeated description may not be provided in the specification. It will be understood that if an element (such as a layer, film, region, or substrate) is referred to as being "on" another element (such as a layer, film, region, or substrate) (e.g., when an element (such as a layer, film, region, or substrate) is referred to as being "on" another element (such as a layer, film, region, or substrate)), it may be directly on the other element (such as a layer, film, region, or substrate) or there may also be intervening elements (such as a layer, film, region, or substrate). In contrast, if an element (such as a layer, film, region, or substrate) is referred to as being "directly on" another element (such as a layer, film, region, or substrate) (e.g., when an element (such as a layer, film, region, or substrate) is referred to as being "directly on" another element (such as a layer, film, region, or substrate)), there are no intervening elements (such as a layer, film, region, or substrate).

[0038] In one or more embodiments, as used herein, the term "layer" includes not only a shape or layer formed over an entire surface if viewed in a plan view (e.g., when viewed in a plan view), but also a shape or layer formed over a partial surface.

[0039] In one or more embodiments, the average particle diameter can be measured by a method highly suitable for those skilled in the art, e.g., by a particle size analyzer (e.g., HORIBA, LA-950 laser particle size analyzer), or by a transmission electron microscope (TEM) or a scanning electron microscope (SEM). In one or more embodiments, the measurement can be carried out by using a dynamic light scattering method, performing data analysis, counting the number of particles in each particle size range, and making calculations based on the data, and an average particle diameter value can be obtained. Unless otherwise defined, the average particle diameter (D 50 ) can refer to the diameter of the particles with a cumulative volume of 50% by volume in the particle size distribution. D50 Refers to the average diameter (or size) of particles whose cumulative volume corresponds to 50% by volume in a particle size distribution (e.g., cumulative distribution), and refers to the value of the particle size corresponding to 50% starting from the smallest particles when the total number of particles is 100% in a distribution curve cumulatively arranged in the order from the smallest particle size to the largest particle size. In the present disclosure, when the particles are spherical, "diameter" indicates the average particle size, and when the particles are non-spherical, "diameter" indicates the major axis length. As used herein, if no other definition is provided (e.g., when no other definition is provided otherwise), the average particle size (D 50 ) refers to the diameter of particles whose cumulative volume is 50% by volume in a particle size distribution obtained by randomly measuring the sizes (diameter or major axis length) of about 20 particles in a scanning electron microscope image.

[0040] In this context, "or" is not construed in an exclusive sense. For example, "A or B" is construed to include A, B, A + B, etc. Further, as used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of...", "one of...", and "selected from..." when before / after a list of elements modify the entire list of elements and do not modify individual elements of the list. For example, "at least one of a, b, and c", "at least one selected from a, b, and c", "at least one selected from a to c", etc. may indicate only a, only b, only c, both a and b (e.g., a and b simultaneously), both a and c (e.g., a and c simultaneously), both b and c (e.g., b and c simultaneously), all of a, b, and c, or variations thereof. The " / " used herein may be construed as "and" or construed as "or" depending on the circumstances.

[0041] As used herein, the term "metal" is construed to include the concepts of common metals, transition metals, and metalloids (semi-metals).

[0042] Positive electrode active material

[0043] In one or more embodiments, the positive electrode active material may include a layered lithium nickel-based composite oxide. Based on 100 mol% of the total moles of metals other than lithium included in the layered lithium nickel-based composite oxide, the nickel content (e.g., amount) may be greater than or equal to about 60 mol%, the aluminum content (e.g., amount) may be about 0.8 mol% to about 1.5 mol%, and the zirconium content (e.g., amount) may be about 0.1 mol% to about 0.3 mol%, and the ratio of the aluminum content (e.g., amount) to the zirconium content (e.g., amount) (Al / Zr) may be greater than or equal to about 5, and the positive electrode active material may have an average particle size (D 50) in the form of single particles of about 1 μm to about 4 μm. In other words, the composition of the positive electrode active material may include a layered or laminated lithium nickel-based composite oxide. Based on the total metal content other than lithium in the layered lithium nickel-based composite oxide, the proportions are as follows: the nickel content is greater than or equal to about 60 mol%, the aluminum content is about 0.8 mol% to about 1.5 mol%, and the zirconium content is about 0.1 mol% to about 0.3 mol%. In addition, the ratio of aluminum to zirconium (Al / Zr) is at least about 5. Here, the positive electrode active material generally exists as single particles by itself, and the measured average particle size or median particle size (D 50 ) is between about 1 μm and about 4 μm. In the present disclosure, "not including one or any component", "excluding one or any component", "free of component", etc. mean that the "component" is not added, selected, or utilized as a component in the composition / element / structure. However, in some embodiments, due to other impurities and / or external factors, it may still include less than an appropriate amount of the "component".

[0044] Even through relatively low-temperature heat treatment, the positive electrode active material can be effectively synthesized, making it economical and conducive to large-scale production, and having high structural stability, ensuring excellent or appropriate cycle life characteristics.

[0045] In this article, single particles (e.g., each particle) can exist alone (without grain boundaries within the particle), consist of one particle, and can be single particles, monolithic structures, integral structures, or non-aggregated particles, where the particles do not aggregate with each other but exist as independent phases from a morphological perspective, and can be represented as single particles (integral particles, single crystals), for example, represented as single crystals. Single particles can exist alone, or single particles can aggregate together. For example, 2 to 9 single particles can aggregate and contact each other.

[0046] In one or more embodiments, single particles can exist alone or 5 or fewer single particles can be attached to each other.

[0047] In one or more embodiments, the average particle size (D 50 )(e.g., representing the point that is smaller than half of the single particles and larger than half of the single particles) can be about 1 μm to about 4 μm, for example, about 1.5 μm to about 4 μm, about 2 μm to about 4 μm, or about 2 μm to about 3.8 μm. Single particle structures that satisfy the above range of average particle size (D 50 ) are structurally stable, can increase the energy density of the positive electrode, and can improve the cycle life characteristics of rechargeable lithium batteries. In this article, the average particle size (D50 )。

[0048] The layered lithium nickel-based composite oxide may be a high-nickel oxide in which the nickel content (e.g., amount) is greater than or equal to about 60 mol% based on 100 mol% of the total moles of metals other than lithium. For example, based on 100 mol% of the total moles of metals other than lithium, the nickel content (e.g., amount) of the layered lithium nickel-based composite oxide may be greater than or equal to about 65 mol%, greater than or equal to about 70 mol%, greater than or equal to about 75 mol%, greater than or equal to about 80 mol%, greater than or equal to about 85 mol%, greater than or equal to about 90 mol%, greater than or equal to about 91 mol% or greater than or equal to about 94 mol% and less than or equal to about 99 mol% or less than or equal to about 98 mol%.

[0049] In addition to nickel, the layered lithium nickel-based composite oxide may contain a specific amount of aluminum and zirconium as a type or kind of dopant. Based on 100 mol% of the total moles of metals other than lithium in the layered lithium nickel-based composite oxide, the aluminum content (e.g., amount) may be about 0.8 mol% to about 1.5 mol%, for example, about 0.8 mol% to about 1.4 mol%, about 0.8 mol% to about 1.3 mol% or about 0.9 mol% to about 1.2 mol. Based on 100 mol% of the total moles of metals other than lithium in the layered lithium nickel-based composite oxide, the zirconium content (e.g., amount) may be about 0.1 mol% to about 0.3 mol%, for example, about 0.1 mol% to about 0.2 mol%.

[0050] In addition, the layered lithium nickel-based composite oxide may have a ratio (Al / Zr) of aluminum content (e.g., amount) to zirconium content (e.g., amount) greater than or equal to about 5, for example, about 5 to about 20, about 5 to about 15 or about 5 to about 10. If the ratio of aluminum content (e.g., amount) to zirconium content (e.g., amount) satisfies the above range, synthesis may be carried out at a relatively low firing temperature without using, for example, an alkaline grain growth promoter during the synthesis process, and due to high structural stability, long cycle life characteristics can be achieved.

[0051] As a specific example, the layered lithium nickel-based composite oxide may be represented by Chemical Formula 1.

[0052] [Chemical Formula 1]

[0053] Li a1 Ni x1 M 1 y1 Al z1 Zr w1 O 2-b1 X b1 ,

[0054] In Chemical Formula 1, 0.9 ≤ a1 ≤ 1.2, 0.6 ≤ x1 ≤ 0.991, 0 ≤ y1 ≤ 0.391, 0.008 ≤ z1 ≤ 0.015, 0.001 ≤ w1 ≤ 0.003, 0.9 ≤ x1 + y1 + z1 + w1 ≤ 1.1, and 0 ≤ b1 ≤ 0.1, M 1 may be (for example, selected from) one or more elements of boron (B), barium (Ba), calcium (Ca), cerium (Ce), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), niobium (Nb), silicon (Si), tin (Sn), strontium (Sr), titanium (Ti), vanadium (V), tungsten (W), and zinc (Zn), and X may be (for example, selected from) one or more elements of fluorine (F), phosphorus (P), and sulfur (S).

[0055] In Chemical Formula 1, 0.9 ≤ a1 ≤ 1.1, 0.9 ≤ a1 ≤ 1.05 or 0.9 ≤ a1 ≤ 1. In Chemical Formula 1, 0.7 ≤ x1 ≤ 0.991 and 0 ≤ y1 ≤ 0.291, 0.8 ≤ x1 ≤ 0.991 and 0 ≤ y1 ≤ 0.191, or 0.9 ≤ x1 ≤ 0.991 and 0 ≤ y1 ≤ 0.091. z1 representing the Al content (for example, amount) may be, for example, 0.008 ≤ z1 ≤ 0.014, 0.008 ≤ z1 ≤ 0.013 or 0.009 ≤ z1 ≤ 0.012. w1 representing the Zr content (for example, amount) may be, for example, 0.001 ≤ w1 ≤ 0.002.

[0056] In Chemical Formula 1, 5 ≤ z1 / w1 may be satisfied, for example, 5 ≤ z1 / w1 ≤ 20, 5 ≤ z1 / w1 ≤ 15 or 5 ≤ z1 / w1 ≤ 10.

[0057] As a more specific example, the layered lithium nickel-based composite oxide may be represented by Chemical Formula 2.

[0058] [Chemical Formula 2]

[0059] Li a2 Ni x2 Co v2 M 2 y2 Al z2 Zr w2 O 2-b2 X b2 ,

[0060] In Chemical Formula 2, 0.9 ≤ a2 ≤ 1.2, 0.6 ≤ x2 < 0.991, 0 < v2 ≤ 0.391, 0 ≤ y2 ≤ 0.391, 0.008 ≤ z2 ≤ 0.015, 0.001 ≤ w2 ≤ 0.003, 0.9 ≤ x2 + v2 + y2 + z2 + w2 ≤ 1.1, and 0 ≤ b2 ≤ 0.1, M2 It may be (e.g., selected from) one or more elements among B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zn, and X may be (e.g., selected from) one or more elements among F, P, and S.

[0061] Chemical formula 2 also satisfies 5 ≤ z2 / w2. For example, 5 ≤ z2 / w2 ≤ 20, 5 ≤ z2 / w2 ≤ 15, or 5 ≤ z2 / w2 ≤ 10.

[0062] Method for preparing a positive electrode active material

[0063] In one or more embodiments, the method for preparing a positive electrode active material may include: (i) performing a coprecipitation reaction of a nickel precursor and an M 1 precursor to prepare a nickel-based composite hydroxide in the form of particles and having micropores inside the particles; (ii) mixing the nickel-based composite hydroxide, a lithium raw material, an aluminum raw material, and a zirconium raw material and performing a heat treatment to prepare a hollow secondary particle including a layered lithium nickel-based composite oxide and having pores inside, as a secondary particle formed by aggregating a plurality of primary particles; and (iii) pulverizing the secondary particle to obtain a positive electrode active material.

[0064] In the M 1 precursor, M 1 may be (e.g., selected from) one or more elements among B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zn. Based on the total moles of 100 mol% of the metals in the nickel-based composite hydroxide, aluminum in the aluminum raw material, and zirconium in the zirconium raw material, the aluminum in the aluminum raw material (e.g., the aluminum content (e.g., amount) of the aluminum raw material) may be about 0.8 mol% to about 1.5 mol%, the zirconium in the zirconium raw material (e.g., the zirconium content (e.g., amount) of the zirconium raw material) may be about 0.1 mol% to about 0.3 mol%, and the ratio (Al / Zr) of the aluminum content (e.g., amount) to the zirconium content (e.g., amount) may be greater than or equal to about 5.

[0065] According to one or more embodiments of the present disclosure, a high-nickel positive electrode active material in the form of single particles can be effectively prepared using a relatively low firing temperature and a simple method without adding an alkaline grain growth promoter or a flux, thereby improving the yield and economic efficiency.

[0066] In one or more embodiments, the above method can be carried out by mixing a nickel-based composite hydroxide and a lithium raw material and performing a heat treatment, and then adding an aluminum raw material and a zirconium raw material together and firing them. At this time, it should be understood that the aluminum raw material and the zirconium raw material act as dopants and, at the same time (e.g., synchronously), act as basic grain growth promoters. For example, when the aluminum raw material and the zirconium raw material are added, particle growth is promoted, so that single particles can be effectively synthesized at a lower temperature compared with the existing single-particle synthesis method. As a result, aggregation of the particles is inhibited or reduced, and the yield of the high-nickel cathode active material is improved. In contrast, existing basic grain growth promoters or fluxes have the following problems: they remain in the cathode after firing and increase the resistance of the cathode, thereby reducing the cycle life of the existing cathode. However, the aluminum raw material and the zirconium raw material of the present disclosure are used as dopants for the cathode active material and do not remain on the surface of the cathode active material, so the cycle life characteristics of the cathode including the cathode active material of the present disclosure can be improved. That is, in one or more embodiments of the present disclosure, the aluminum raw material and the zirconium raw material play a dual role as a dopant and a basic grain growth promoter, enhancing particle synthesis at a lower temperature, reducing aggregation, and improving the yield of the high-nickel cathode active material. Different from the conventional basic grain growth promoters whose cycle life deteriorates due to residues after firing, these materials in one or more embodiments of the present invention do not remain on the surface of the cathode active material, thereby improving the cycle life of the cathode.

[0067] Hereinafter, a method for preparing a cathode active material will be described in more detail.

[0068] The nickel-based composite hydroxide can be a precursor of the cathode active material and can be synthesized by a coprecipitation reaction. In the coprecipitation reaction, the nickel precursor can be a hydroxide, oxide, nitrate, sulfate, carbonate, and / or a combination thereof (e.g., any suitable combination) of nickel. M 1 The precursor can be a hydroxide, oxide, nitrate, sulfate, carbonate, and / or a combination thereof (e.g., any suitable combination) containing M 1 element.

[0069] In the coprecipitation reaction, in addition to the nickel precursor and the M 1 precursor, a complexing agent and a pH controller can also be used. The complexing agent plays a role in controlling the reaction rate of precipitate formation in the coprecipitation reaction and can include, for example, ammonium hydroxide (NH 4 OH), citric acid, and / or a combination thereof (e.g., any suitable combination). The concentration of the complexing agent can be about 0.1 M to about 1.5 M, for example, about 0.1 M to about 1.4 M or about 0.5 M to about 1.4 M. The pH controller is used to control the pH of the reactants and can include, for example, sodium hydroxide (NaOH), sodium carbonate (Na2 CO 3 )、 sodium oxalate (Na 2 C 2 O 4 ) and / or combinations thereof (e.g., any suitable combination).

[0070] The coprecipitation reaction may include a first step (e.g., action or task) of reacting at a pH in the range of about 11 to about 12 (also referred to as the first reaction) and a second step (e.g., action or task) of reacting at a pH lower than the pH of the first step (e.g., action or task) (also referred to as the second reaction). The pH of the first step (e.g., action or task) may be, for example, about 11.5 to about 12, about 11.6 to about 11.9, or about 11.7 to about 11.8, and may be regarded as a pore-forming step (e.g., action or task). The second step (e.g., action or task) may be a step (e.g., action or task) of reacting at a pH lower than the pH of the first step (e.g., action or task), and may be a type or kind of particle growth step (e.g., action or task). By changing the pH in two or more steps, the synthesis rate can be changed. As a result, a nickel-based composite hydroxide having micropores inside the particles can be obtained. The pH of the second step (e.g., action or task) may be, for example, about 10 to about 11.9, about 10.5 to about 11.7, about 11 to about 11.7, about 11.2 to about 11.6, or about 11.3 to about 11.6. For example, the difference between the pH of the first step (e.g., action or task) and the pH of the second step (e.g., action or task) may be about 0.1 to about 1.5, for example, about 0.1 to about 1.0, about 0.1 to about 0.8, about 0.1 to about 0.6, about 0.1 to about 0.5, about 0.1 to about 0.3, or about 0.1 to about 0.2.

[0071] The first step (e.g., action or task) may be carried out for about 6 hours to about 12 hours or about 8 hours to about 10 hours. The second step (e.g., action or task) may be carried out for about 10 hours to about 30 hours, about 15 hours to about 25 hours, or about 18 hours to about 24 hours.

[0072] The prepared nickel-based composite hydroxide can be represented by Chemical Formula 11.

[0073] [Chemical Formula 11]

[0074] Ni x11 M 1 y11 (OH) 2

[0075] In Chemical Formula 11, 0.6 ≤ x11 ≤ 1, 0 ≤ y11 ≤ 0.4 and 0.9 ≤ x11 + y11 ≤ 1.1, and M 1may be (for example, selected from) one or more elements among B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zn.

[0076] In Chemical Formula 11, 0.7 ≤ x11 ≤ 1 and 0 ≤ y11 ≤ 0.3, 0.8 ≤ x11 ≤ 1 and 0 ≤ y11 ≤ 0.2, or 0.9 ≤ x11 < 1 and 0 < y11 ≤ 0.1.

[0077] As a specific example, the nickel-based composite hydroxide may be represented by Chemical Formula 12.

[0078] [Chemical Formula 12]

[0079] Ni x12 Co v12 M 2 y12 (OH) 2

[0080] In Chemical Formula 12, 0.6 ≤ x12 < 1, 0 < v12 ≤ 0.4, 0 ≤ y12 ≤ 0.4, and 0.9 ≤ x12 + v12 + y12 ≤ 1.1, and M 2 may be (for example, selected from) one or more elements among B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zn.

[0081] In one or more embodiments, the nickel-based composite hydroxide may be in the form of particles. For example, the particles of the nickel-based composite hydroxide may include an inner portion containing a plurality of micropores and an outer portion surrounding the inner portion and having a dense structure. Herein, the inner portion of the nickel-based composite hydroxide particle may refer to a region of 50% to 70% (e.g., 60%) of the total volume starting from the center of the particle, or may refer to the remaining region from the center of the particle to the surface of the particle excluding the outer portion (which may be a region within 3 μm from the outermost edge towards the center of the particle).

[0082] Thus, by using the nickel-based composite hydroxide having micropores inside the particles, a positive electrode active material in the form of a plurality of hollow secondary particles (e.g., one hollow secondary particle) can be effectively obtained. In this case, the secondary particles can be easily pulverized during the pulverization process to obtain good or appropriate single particles.

[0083] For example, the nickel-based composite hydroxide may be amorphous (non-crystalline), which can be confirmed by X-ray diffraction analysis.

[0084] In step (ii) of the method for preparing a positive electrode active material (e.g., an action or task), based on 1 mole of the total metal of nickel-based composite hydroxide, the metal of aluminum raw material and zirconium of zirconium raw material, the lithium content (e.g., amount) of the lithium raw material may be about 0.9 moles to about 1.2 moles, e.g., about 0.9 moles to about 1.1 moles, about 0.9 moles to about 1.05 moles, about 1 mole to about 1.1 moles or about 1.01 moles to about 1.04 moles. By appropriately or suitably controlling the molar ratio of the lithium raw material, a positive electrode active material in the form of single particles with a stable structure and good or appropriate quality can be prepared.

[0085] The lithium raw material may be, for example, lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate and / or a combination thereof (e.g., any suitable combination), e.g., anhydrous lithium hydroxide.

[0086] Based on 100 mol% of the total moles of nickel-based composite hydroxide, the metal of aluminum raw material and zirconium of zirconium raw material, the aluminum content (e.g., amount) of the aluminum raw material may be designed to be about 0.8 mol% to about 1.5 mol%, and the zirconium content (e.g., amount) of the zirconium raw material may be designed to be about 0.1 mol% to about 0.3 mol%. For example, the aluminum content (e.g., amount) of the aluminum raw material may be about 0.8 mol% to about 1.4 mol%, about 0.8 mol% to about 1.3 mol% or about 0.9 mol% to about 1.2 mol%. For example, the zirconium content (e.g., amount) of the zirconium raw material may be about 0.1 mol% to about 0.2 mol%.

[0087] Meanwhile, the ratio (Al / Zr) of the aluminum content (e.g., amount) to the zirconium content (e.g., amount) may be designed to be 5 or greater, and may be, for example, about 5 to about 20, about 5 to about 15 or about 5 to about 10.

[0088] As described above, the aluminum raw material and the zirconium raw material are understood to act as dopants and, at the same time (e.g., synchronously), as basic grain growth promoters, where the aluminum raw material and the zirconium raw material are respectively injected in the above content (e.g., amount) ranges (e.g., the amount of the aluminum raw material and the amount of the zirconium raw material) to obtain single particles in an optimal or suitable state.

[0089] The aluminum raw material may be, for example, aluminum oxide, and specifically may be Al 2 O 3 . Additionally, the zirconium raw material may be, for example, zirconium oxide, and specifically may be ZrO 2 .

[0090] In one or more embodiments, the method for preparing the positive electrode active material can perform heat treatment at a relatively lower temperature compared to the existing single particle synthesis method. For example, even when heat treatment is performed at a relatively lower temperature, a desired or appropriate positive electrode active material in the form of good or appropriate single particles can be obtained. Accordingly, this method can simplify the process, improve economic efficiency, reduce the problem of particle aggregation, and thus improve the yield and processability. For example, heat treatment can be performed at less than or equal to about 900 °C or less than or equal to about 890 °C, less than or equal to about 850 °C or less than or equal to about 810 °C, for example, about 700 °C to about 900 °C, 710 °C to about 890 °C, about 730 °C to about 850 °C, or about 750 °C to about 810 °C.

[0091] For example, the heat treatment can be performed in an oxidizing gas atmosphere for about 4 hours to about 20 hours, about 5 hours to about 15 hours, or about 6 hours to about 12 hours.

[0092] In one or more embodiments, the method for preparing the positive electrode active material may not add an alkaline grain growth promoter or a flux in the process of mixing a nickel-based composite hydroxide, a lithium raw material, an aluminum raw material, and a zirconium raw material and heat-treating them (for example, a mixture of a nickel-based composite hydroxide, a lithium raw material, an aluminum raw material, and a zirconium raw material). Accordingly, an increase in resistance caused by residues after heat treatment can be prevented or reduced, thereby improving the cycle life characteristics of the rechargeable lithium battery, and since there is no need to add a process for removing residues, the yield and processability can be improved without a process for removing residues.

[0093] Through heat treatment, hollow secondary particles including a layered lithium nickel-based composite oxide can be obtained. Herein, by adding an aluminum raw material and a zirconium raw material, the primary particles forming the secondary particles can sufficiently grow into single crystals. In addition, the secondary particles can have a hollow structure with pores inside, so they can be easily pulverized in a subsequent pulverization process.

[0094] In one or more embodiments, the average particle size (D 50 ) of the obtained secondary particles can be about 10 μm to about 20 μm, for example, about 10 μm to about 18 μm or about 12 μm to about 16 μm. In one or more embodiments, the average particle size (D 50 ) of the secondary particles can be measured by SEM images.

[0095] In one or more embodiments, the average particle size (D 50 ) of the primary particles constituting the secondary particles can be about 1 μm to about 4 μm, for example, about 1.5 μm to about 4 μm, about 2 μm to about 4 μm, or about 2 μm to about 3.8 μm. In one or more embodiments, the average particle size (D50 )。

[0096] In one or more embodiments, the size of the pores inside the secondary particles can be from about 1 μm to about 9 μm, for example, about 2 μm to about 8 μm, about 3 μm to about 7 μm, etc. In one or more embodiments, the size of the pores inside the secondary particles can be measured from the SEM image of the cross-section of the secondary particles, and can refer to the length of the major axis of the pores.

[0097] In one or more embodiments, the obtained layered lithium nickel-based composite oxide can be represented by Chemical Formula 1, and the description of Chemical Formula 1 is as described above.

[0098] In step (iii) of the method for preparing the positive electrode active material (e.g., action or task), the pulverization of the secondary particles refers to breaking the secondary particles, and can be understood as a process of separating the primary particles constituting the secondary particles from each other into individual particles. By pulverization, the aforementioned high-nickel-based positive electrode active material in the form of individual particles with an average particle size (D 50 ) of about 1 μm to about 4 μm can be obtained.

[0099] In one or more embodiments, in the preparation method, nickel-based composite hydroxide having micropores inside can be used as a precursor to obtain a layered lithium nickel-based composite oxide in the form of hollow secondary particles after heat treatment. Accordingly, the secondary particles can be easily pulverized into individual particles. Additionally, if the nickel-based composite hydroxide and a lithium raw material are mixed together and heat-treated (e.g., when the nickel-based composite hydroxide and the lithium raw material are mixed together and heat-treated), an aluminum raw material and a zirconium raw material can also be added thereto and heat-treated together to grow the primary particles into individual particles with sufficient size at a relatively low temperature of about 900 °C or lower, thereby obtaining secondary particles in which the primary particles are aggregated. The secondary particles can be pulverized to obtain the desired or appropriate positive electrode active material in the form of good or appropriate individual particles.

[0100] In one or more embodiments, pulverization can be performed using a jet mill or an air classifier mill (ACM) equipment. If pulverization is performed using a jet mill (e.g., when pulverization is performed using a jet mill), the air pressure can be appropriately or suitably adjusted, for example, at an air pressure of about 2 bar to about 8 bar or about 4 bar to about 6 bar, so that the pulverized product can have a bulk density of about 0.2 g / cm 3 ~about 0.5 g / cm 3 . In one or more embodiments, for example, the pulverization process can be performed for about 10 minutes to about 120 minutes, for example, about 10 minutes to about 80 minutes, about 10 minutes to about 60 minutes, or about 20 minutes to about 50 minutes.

[0101] In one or more embodiments, the method for preparing the positive electrode active material may further include a secondary heat treatment after pulverizing the secondary particles. In one or more embodiments, for example, the secondary heat treatment may be performed in an oxidizing gas atmosphere at about 500 °C to about 900 °C, about 600 °C to about 800 °C, or about 650 °C to about 750 °C.

[0102] In one or more embodiments, the method for preparing the positive electrode active material may include pulverizing a product (e.g., secondary particles) and mixing the pulverized product with a coating raw material, and then performing a secondary heat treatment after mixing the pulverized product and the coating raw material. Thereby, individual particles coated with a desired or appropriate material can be obtained.

[0103] In one or more embodiments, the coating raw material is not particularly limited and may be, for example, a raw material including one or more elements selected from aluminum (Al), B, Co, Mg, V, Zn, and Zr, and may be a hydroxide, oxide, sulfate, nitrate, or carbonate containing the above elements.

[0104] In one or more embodiments, the positive electrode active material obtained by the above preparation method may include a layered lithium nickel-based composite oxide, and may include individual particles having an average particle diameter (D 50 ) of about 1 μm to about 4 μm, and may include, for example, a mixture of uncrushed hollow secondary particles and crushed individual particles.

[0105] Positive electrode

[0106] In one or more embodiments, a positive electrode for a rechargeable lithium battery containing the aforementioned positive electrode active material may be provided. For example, the positive electrode includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector, and the positive electrode active material layer may include the aforementioned positive electrode active material.

[0107] In the present disclosure, the positive electrode active material may include a layered lithium nickel-based composite oxide, wherein, based on 100 mol% of the total moles of metals other than lithium in the layered lithium nickel-based composite oxide, the nickel content (e.g., amount) may be greater than or equal to about 60 mol%, the aluminum content (e.g., amount) may be about 0.8 mol% to about 1.5 mol%, and the zirconium content (e.g., amount) may be about 0.1 mol% to about 0.3 mol%. Additionally, the ratio (Al / Zr) of the aluminum content (e.g., amount) to the zirconium content (e.g., amount) may be greater than or equal to about 5. The positive electrode active material layer may include positive electrode active material in the form of individual particles having an average particle diameter (D 50 ) of about 1 μm to about 4 μm.

[0108] For example, the positive electrode active material layer may include a first positive electrode active material in the form of single particles and a second positive electrode active material in the form of secondary particles. In the present context, the second positive electrode active material may refer to uncrushed hollow secondary particles, and the first positive electrode active material may refer to single particles formed by crushing the second positive electrode active material.

[0109] In the positive electrode active material layer, based on the total weight of 100 wt% of the first positive electrode active material and the second positive electrode active material, about 5 wt% to about 60 wt% of the first positive electrode active material may be included, and based on the total weight of 100 wt% of the first positive electrode active material and the second positive electrode active material, about 40 wt% to about 95 wt% of the second positive electrode active material may be included. For example, the weight ratio of the first positive electrode active material to the second positive electrode active material may be about 5:95 to about 60:40, for example, about 10:90 to about 50:50 or about 20:80 to about 40:60, but is not particularly limited thereto.

[0110] In one or more embodiments, the positive electrode active material layer may optionally further include a binder, a conductive material, and / or a combination thereof (e.g., any suitable combination).

[0111] Binder

[0112] The binder may improve the binding characteristics of the positive electrode active material particles to each other and the binding characteristics of the positive electrode active material particles to the positive electrode current collector. Examples of the binder may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, and / or nylon, but are not limited thereto.

[0113] Conductive material

[0114] A conductive material (e.g., an electronic conductor) may be included to provide electrode conductivity, and any conductive material may be used as the conductive material unless it causes a chemical change. Examples of the conductive material may include carbonaceous materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.); metallic materials including metal powders or metal fibers such as copper, nickel, aluminum, silver, etc.; and / or conductive polymers (such as polyphenylene derivatives); and / or mixtures thereof (e.g., any suitable mixture).

[0115] Based on 100 wt% of the positive electrode active material layer, the respective contents (e.g., amounts) of the binder and the conductive material may be about 0.5 wt% to about 5 wt%.

[0116] The positive electrode current collector may include aluminum foil, but the present disclosure is not limited thereto.

[0117] Rechargeable lithium battery

[0118] Some embodiments provide a rechargeable lithium battery including the aforementioned positive electrode, negative electrode, and electrolyte. As an example, the rechargeable lithium battery may include a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, and an electrolyte.

[0119] Depending on the shape, the rechargeable lithium battery may be classified into a cylindrical battery, a prismatic battery, a pouch battery, a coin-shaped battery, etc. In one or more embodiments, Figures 1 to 4 Each is a schematic diagram showing a rechargeable lithium battery, where Figure 1 is a cylindrical battery, Figure 2 is a prismatic battery, and Figure 3 and Figure 4 are each a pouch battery. Referring to Figures 1 to 4 , the rechargeable lithium battery 100 includes an electrode assembly 40 and a housing 50 that houses the electrode assembly 40. The electrode assembly 40 has a separator 30 inserted between the positive electrode 10 and the negative electrode 20. The positive electrode 10, negative electrode 20, and separator 30 may be impregnated with an electrolyte. As shown in Figure 1 , the rechargeable lithium battery 100 may include a sealing member 60 that seals the housing 50. Additionally, in Figure 2 , the rechargeable lithium battery 100 may include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. As shown in Figure 3 and Figure 4 , the rechargeable lithium battery 100 includes electrode tabs 70 that serve as a circuit path for guiding the current formed in the electrode assembly 40 to the outside. For example, a positive electrode tab 71 and a negative electrode tab 72.

[0120] Negative electrode

[0121] The negative electrode may include a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector. The negative electrode active material layer may include a negative electrode active material and may further include a binder, a conductive material, and / or a combination thereof (e.g., any suitable combination).

[0122] Negative electrode active material

[0123] The negative electrode active material may include a material that reversibly intercalates / deintercalates lithium ions, lithium metal, a lithium metal alloy, a material capable of doping / dedoping lithium, and / or a transition metal oxide.

[0124] Materials that can reversibly embed / extract lithium ions may include, for example, crystalline carbon, amorphous carbon, and / or combinations thereof (e.g., any suitable combination) as carbonaceous negative electrode active materials. The crystalline carbon can be natural graphite or artificial graphite that is amorphous, flaky, sheet-like, spherical, and / or fibrous (e.g., in the form of fibers). The amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbonized product, calcined coke, etc.

[0125] Lithium metal alloys include alloys of lithium with metals selected from sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), Mg, Ca, Sr, Si, antimony (Sb), lead (Pb), indium (In), zinc (Zn), barium (Ba), radium (Ra), germanium (Ge), aluminum (Al), and tin (Sn).

[0126] Materials capable of doping / dedoping lithium can be Si-based negative electrode active materials or Sn-based negative electrode active materials. The Si-based negative electrode active materials can include silicon, silicon-carbon composites, SiO x (0 < x ≤ 2), Si-Q alloys (where Q is an element selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements (excluding Si), Group 15 elements, Group 16 elements, transition metals, rare earth elements, and / or combinations thereof (e.g., any suitable combination), e.g., Mg, Ca, Sr, Ba, Ra, scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), (Rf), V, Nb, tantalum (Ta), dubnium (Db), Cr, Mo, W, (Sg), technetium (Tc), rhenium (Re), (Bh), iron (Fe), Pb, ruthenium (Ru), osmium (Os), (Hs), rhodium (Rh), iridium (Ir), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), B, Al, gallium (Ga), Sn, In, thallium (Tl), Ge, P, arsenic (As), Sb, bismuth (Bi), S, selenium (Se), tellurium (Te), polonium (Po), and / or combinations thereof (e.g., any suitable combination)) and / or combinations thereof (e.g., any suitable combination). The Sn-based negative electrode active materials can be Sn, SnO x (0 < x ≤ 2) (e.g., SnO 2 ), Sn alloys, and / or combinations thereof (e.g., any suitable combination).

[0127] The silicon-carbon composite can be a composite of silicon and amorphous carbon. The average particle size (D 50)It can be, for example, from about 0.5 μm to about 20 μm. In one or more embodiments, the silicon-carbon composite can be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it can include secondary particles (cores) in which silicon primary particles are assembled or aggregated, and an amorphous carbon coating (shell) on the surface of the secondary particles. Amorphous carbon can also be present between the silicon primary particles. For example, the silicon primary particles can be coated with amorphous carbon. The secondary particles can be dispersed in the amorphous carbon matrix.

[0128] The silicon-carbon composite can further include crystalline carbon. For example, the silicon-carbon composite can include: a core including crystalline carbon and silicon particles and an amorphous carbon coating on the surface of the core. The crystalline carbon can be artificial graphite, natural graphite, and / or a combination thereof (e.g., any suitable combination). The amorphous carbon can include soft carbon, hard carbon, mesophase pitch carbonization products, and calcined coke.

[0129] In one or more embodiments, if the silicon-carbon composite includes silicon and amorphous carbon (e.g., when the silicon-carbon composite includes silicon and amorphous carbon), based on 100 wt% of the silicon-carbon composite, the silicon content (e.g., amount) can be from about 10 wt% to about 50 wt%, and based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of amorphous carbon can be from about 50 wt% to about 90 wt%. Additionally, if the silicon-carbon composite includes silicon, amorphous carbon, and crystalline carbon (e.g., when the silicon-carbon composite includes silicon, amorphous carbon, and crystalline carbon), based on 100 wt% of the silicon-carbon composite, the silicon content (e.g., amount) can be from about 10 wt% to about 50 wt%; based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of crystalline carbon can be from about 10 wt% to about 70 wt%; and based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of amorphous carbon can be from about 20 wt% to about 40 wt%.

[0130] Additionally, the thickness of the amorphous carbon coating can be from about 5 nm to about 100 nm. The average particle size (D 50 ) of the silicon particles (primary particles) can be from about 10 nm to about 1 μm or from about 10 nm to about 200 nm. The silicon particles can exist as silicon alone, in the form of a silicon alloy, or in an oxidized form of silicon. The oxidized form of silicon can be represented by SiO x (0 < x ≤ 2). At this time, the atomic content (e.g., amount) ratio of Si:O indicating the degree of oxidation can be from about 99:1 to about 33:67. As used herein, if no other definition is provided (e.g., when no other definition is provided), the average particle size (D 50 ) indicates the diameter of the particles with a cumulative volume of about 50% by volume in the particle size distribution.

[0131] In one or more embodiments, a Si-based negative electrode active material or a Sn-based negative electrode active material may be mixed with a carbon-based negative electrode active material. If a Si-based negative electrode active material or a Sn-based negative electrode active material is mixed and utilized with a carbon-based negative electrode active material (e.g., when a Si-based negative electrode active material or a Sn-based negative electrode active material is mixed and utilized with a carbon-based negative electrode active material), the mixing ratio may be a weight ratio of about 1:99 to about 90:10.

[0132] Binder

[0133] The binder is used to well bond the negative electrode active material particles to each other and is also used to bond the negative electrode active material to the negative electrode current collector. The binder may be a non-aqueous binder, an aqueous binder, a dry binder, and / or a combination thereof (e.g., any suitable combination).

[0134] In one or more embodiments, the non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, and / or a combination thereof (e.g., any suitable combination).

[0135] In one or more embodiments, the aqueous binder may include styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, poly(ethylene oxide), polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene-propylene-diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and / or a combination thereof (e.g., any suitable combination).

[0136] In one or more embodiments, if the aqueous binder is used as a binder in the negative electrode active material layer (e.g., when the aqueous binder is used as a binder in the negative electrode active material layer), a cellulose-based compound capable of imparting viscosity may be further included. As the cellulose-based compound, one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and its alkali metal salts may be mixed and utilized. The alkali metal may be Na, K, or lithium (Li).

[0137] In one or more embodiments, the dry binder may be a polymer material capable of being fibrillated and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, poly(ethylene oxide), and / or a combination thereof (e.g., any suitable combination).

[0138] Conductive material

[0139] It includes a conductive material (e.g., an electronic conductor) to provide electrode conductivity, and any conductive material can be used as the conductive material unless it causes a chemical change. Examples of the conductive material can include carbonaceous materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.); metallic materials including metal powders or metal fibers such as copper, nickel, aluminum, silver, etc.; conductive polymers (such as polyphenylene derivatives); and / or their mixtures (e.g., any suitable mixture).

[0140] Based on 100 wt% of the negative electrode active material layer, the content (e.g., amount) of the negative electrode active material can be about 95 wt% to about 99.5 wt%, and based on 100 wt% of the negative electrode active material layer, the content (e.g., amount) of the binder can be about 0.5 wt% to about 5 wt%. For example, the negative electrode active material layer can include about 90 wt% to about 99 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and about 0.5 wt% to about 5 wt% of the conductive material.

[0141] Negative electrode current collector

[0142] The negative electrode current collector can include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), and / or their alloys, and can be in the form of foil, sheet, and / or foam. The thickness of the negative electrode current collector can be, for example, about 1 μm to about 20 μm, about 5 μm to about 15 μm, or about 7 μm to about 10 μm.

[0143] Electrolyte

[0144] For example, the electrolyte for a rechargeable lithium battery can be an electrolyte that can include a non-aqueous organic solvent and a lithium salt.

[0145] The non-aqueous organic solvent serves as a medium for transporting ions participating in the electrochemical reaction of the battery. The non-aqueous organic solvent can include carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents, and / or their combinations (e.g., any suitable combination).

[0146] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. Ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolide, mevalonolactone, valerolactone, caprolactone, etc. Ether solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. Additionally, ketone solvents may include cyclohexanone, etc. Alcohol solvents may include ethanol, isopropanol, etc., and aprotic solvents may include nitriles (such as, R-CN, where R is a C2-C20 straight-chain hydrocarbon group, branched-chain hydrocarbon group or cycloalkyl group, and may include double bonds, aromatic rings or ether groups, etc.); amides (such as, dimethylformamide); dioxolanes (such as, 1,3-dioxolane, 1,4-dioxolane, etc.); and / or sulfolane, etc.

[0147] The non-aqueous organic solvent may be used alone or as a mixture of two or more types (or kinds), and if two or more types (kinds) are used as a mixture (for example, when two or more types (kinds) are used as a mixture), the mixing ratio may be appropriately or suitably adjusted according to the desired or appropriate battery performance, which is widely applicable to those skilled in the art.

[0148] In one or more embodiments, if a carbonate solvent is utilized (for example, when a carbonate solvent is utilized), a cyclic carbonate and a chain carbonate may be mixed and utilized, and the cyclic carbonate and the chain carbonate may be mixed in a volume ratio of about 1:1 to about 1:9.

[0149] In one or more embodiments, the non-aqueous organic solvent may further include an aromatic hydrocarbon organic solvent. For example, the carbonate solvent and the aromatic hydrocarbon organic solvent may be mixed and utilized in a volume ratio of about 1:1 to about 30:1.

[0150] In one or more embodiments, the electrolyte may further include vinylene ethylene carbonate, vinylene carbonate and / or ethylene carbonate compounds to improve the battery cycle life.

[0151] Examples of ethylene carbonate compounds may include fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate and / or cyanoethylene carbonate.

[0152] Lithium salts dissolved in non-aqueous organic solvents supply lithium ions in a battery, ensuring the basic operation of a rechargeable lithium battery and improving the transport of lithium ions between the positive and negative electrodes. Examples of lithium salts may include those selected from LiPF 6 、LiBF 4 、LiSbF 6 、LiAsF 6 、LiClO 4 、LiAlO 2 、LiAlCl 4 、LiPO 2 F 2 、LiCl、LiI、LiN(SO 3 C 2 F 5 ) 2 、Li(FSO 2 ) 2 N(lithium bis(fluorosulfonyl)imide, LiFSI), LiC 4 F 9 SO 3 、LiN(C x F 2x+1 SO 2 )(C y F 2y+1 SO 2 )(where x and y are integers from 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro bis(oxalato)phosphate (LiDFBOP), and / or lithium bis(oxalato)borate (LiBOB), at least one of them.

[0153] The concentration of the lithium salt can be in the range of about 0.1 M to about 2.0 M. In one or more embodiments, if the concentration of the lithium salt is within the above range (e.g., when the concentration of the lithium salt is within the above range), the electrolyte has appropriate or suitable ionic conductivity and viscosity, so excellent or appropriate performance can be achieved, and lithium ions can move effectively.

[0154] Separator

[0155] Depending on the type or kind of the rechargeable lithium battery, a separator may be present between the positive and negative electrodes. The separator may include a polyethylene separator, a polypropylene separator, a polyvinylidene fluoride separator, or a multilayer film of two or more of their layers, such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, a polypropylene / polyethylene / polypropylene three-layer separator, etc.

[0156] The separator may include a porous substrate and a coating on the surface (e.g., one or two surfaces (e.g., opposite surfaces)) of the porous substrate, and the coating includes an organic material, an inorganic material, and / or a combination thereof (e.g., any suitable combination).

[0157] The porous substrate may be a polymer film formed of a copolymer or mixture of any one polymer selected from the following or two or more thereof: polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyether ketones, polyaryl ether ketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene ethers, cycloolefin copolymers, polyphenylene sulfides, polyethylene naphthalate, glass fibers, polytetrafluoroethylene (e.g., ).

[0158] The porous substrate may have a thickness of about 1 μm to about 40 μm, for example, about 1 μm to about 30 μm, about 1 μm to about 20 μm, about 5 μm to about 15 μm, or about 10 μm to about 15 μm.

[0159] The organic material may include a (meth)acrylic copolymer including a first structural unit and a second structural unit, the first structural unit being derived from (meth)acrylamide, and the second structural unit including at least one of a structural unit derived from (meth)acrylic acid or (meth)acrylate and a structural unit derived from (meth)acrylamidosulfonic acid or a salt thereof.

[0160] The inorganic material may include inorganic particles selected from Al 2 O 3 、SiO 2 、TiO 2 、SnO 2 、CeO 2 、MgO, NiO, CaO, GaO, ZnO, ZrO 2 、Y 2 O 3 、SrTiO 3 、BaTiO 3 、Mg(OH) 2 、boehmite and / or a combination thereof (e.g., any suitable combination), but the present disclosure is not limited thereto. The average particle size (D 50 ) of the inorganic particles may be about 1 nm to about 2000 nm, for example, about 100 nm to about 1000 nm or about 100 nm to about 700 nm.

[0161] The organic material and the inorganic material may be mixed in one coating, and / or coatings including the organic material and coatings including the inorganic material may be stacked.

[0162] The thickness of the coating may be about 0.5 μm to about 20 μm, for example, about 1 μm to about 10 μm or about 1 μm to about 5 μm.

[0163] Embodiments and comparative examples of the present disclosure are described in more detail. However, the following embodiments are only embodiments of the present disclosure, and the present disclosure is not limited to the following embodiments.

[0164] Example 1

[0165] 1. Preparation of positive electrode active material

[0166] (1) Preparation of nickel-based composite hydroxide

[0167] A nickel-based composite hydroxide having micropores inside the particles is prepared by the following coprecipitation reaction. First, nickel sulfate, cobalt sulfate, and manganese sulfate are dissolved in a solvent of distilled water to have a molar ratio of Ni:Co:Mn = 95:4:1, thereby preparing a metal raw material mixed solution. In addition, an aqueous solution of ammonia water (NH 4 OH) as a complexing agent and sodium hydroxide (NaOH) as a pH controller is prepared. Here, the concentration of ammonia water is 10 wt%, and the concentration of the aqueous solution of sodium hydroxide is 20 wt%. Subsequently, the metal raw material mixed solution, ammonia water, and the aqueous solution of sodium hydroxide are added to the reactor.

[0168] By setting the pH value inside the reactor to 11.75 and stirring the mixture for 10 hours (the first step (e.g., action or task)), and then by lowering the pH value to 11.55 and stirring for 22 hours (the second step (e.g., action or task)), a synthesis rate difference is generated between the inside and outside of the particles, thereby synthesizing a nickel-based composite hydroxide having micropores inside the particles.

[0169] The slurry solution in the reactor is filtered, rinsed with high-purity distilled water, and dried in a hot air oven at 180 °C for 24 hours to obtain a nickel-based composite hydroxide (Ni 0.95 Co 0.04 Mn 0.01 (OH) 2 ) having a hollow structure. The obtained nickel-based composite hydroxide is in the form of secondary particles formed by aggregating a plurality of primary particles, and the secondary particles have an average particle size (D 50 ) of about 13.2 μm as measured by SEM image.

[0170] (2) Preparation of positive electrode active material

[0171] The prepared nickel-based composite hydroxide is mixed with anhydrous lithium hydroxide, Al 2 O 3 and ZrO 2 In this case, anhydrous lithium hydroxide is mixed to have a lithium molar ratio of 1.05 based on the total moles of the metal of the nickel-based composite hydroxide. In addition, Al 2 O 3and ZrO 2 a metal based on nickel - type composite hydroxide, Al 2 O 3 Al and ZrO of 2 For a total mole of 100 mol% of Zr, it has 1 mol% of Al and 0.1 mol% of Zr.

[0172] The mixture is heat - treated in an oxygen atmosphere at 810 °C for 8 hours. It is confirmed that the heat - treated product has Li in the form of hollow secondary particles 1.00 Ni 0.939 Co 0.04 Mn 0.01 Al 0.01 Zr 0.001 O 2 composition. Figure 5 An SEM image of the surface of the secondary particles is shown. When measured by the SEM image, the secondary particles have an average particle size (D 50 ) of about 13.5 μm, the primary particles constituting the secondary particles have an average particle size (D 50 ) of about 2.7 μm, and the pores inside the secondary particles have a size of about 4 μm.

[0173] At a pressure of about 5 bar, the heat - treated obtained material is pulverized in a jet mill for 20 minutes to obtain the positive electrode active material in the form of single particles, and the SEM image of its surface is provided in Figure 6 .

[0174] 2. Manufacture of a rechargeable lithium - battery cell

[0175] 98.5 wt% of the positive electrode active material, 1.0 wt% of the polyvinylidene fluoride binder, and 0.5 wt% of the carbon nanotube conductive material are mixed to prepare the positive electrode active material layer slurry, and the positive electrode active material layer slurry is coated on an aluminum foil current collector, then dried and pressed to manufacture the positive electrode. The manufactured positive electrode includes the positive electrode active material in the form of pulverized single particles.

[0176] The negative electrode active material layer slurry is prepared by mixing 97.5 wt% of graphite negative electrode active material, 1.5 wt% of carboxymethyl cellulose, and 1 wt% of styrene - butadiene rubber in an aqueous solvent. The negative electrode active material layer slurry is coated on a copper foil current collector, dried and pressed, thereby manufacturing the negative electrode.

[0177] The positive electrode and the negative electrode are used together with a polytetrafluoroethylene separator and an electrolyte prepared by dissolving 1 M LiPF 6 in a mixed solvent of ethylene carbonate and dimethyl carbonate with a volume ratio of 3:7 to manufacture a rechargeable lithium - battery cell by a general method.

[0178] Example 2

[0179] The positive electrode active material and the rechargeable lithium battery cell were produced in substantially the same manner as in Example 1, except that ZrO was used 2 to prepare the positive electrode active material so that, based on 100 mol% of the total moles of the nickel-based composite hydroxide, the metal (e.g., Al 2 O 3 of Al and ZrO 2 of Zr) had 0.2 mol% of Zr.

[0180] Figure 7 is an SEM image of the surface of the secondary particles prepared in Example 2, and Figure 8 is an SEM image of the surface of the crushed single particles. When measured by SEM, the average particle diameter (D 50 ) of the secondary particles of Example 2 was about 14 μm, and the average particle diameter (D 50 ) of the primary particles constituting the secondary particles was about 2.7 μm.

[0181] Comparative Example 1

[0182] The positive electrode active material and the rechargeable lithium battery cell were produced in substantially the same manner as in Example 1, except that ZrO was not mixed 2 to prepare the positive electrode active material. Figure 9 is an SEM image of the surface of the secondary particles prepared in Comparative Example 1.

[0183] For Comparative Example 1, since the primary particles constituting the secondary particles did not crystallize into a sufficient size during the heat treatment at 810 °C, the secondary particles were not crushed into single particles by a jet mill.

[0184] Comparing Figure 9 of Comparative Example 1 with Figure 5 of Example 1 and Figure 7 of Example 2, it was confirmed that by adding Al 2 O 3 and ZrO 2 at respective set or predetermined contents (e.g., amounts) for Al and Zr doping under the same heat treatment temperature condition of 810 °C, the grain growth, e.g., the growth of the primary particles or the growth of the single crystals of the primary particles, was promoted.

[0185] Comparative Example 2

[0186] The positive electrode active material and the rechargeable lithium battery cell were produced in substantially the same manner as in Example 1, except that ZrO was added 2Prepare a positive electrode active material so that, based on 100 mol% of the total moles of the metal in the nickel-based composite hydroxide (e.g., Al 2 O 3 of Al and ZrO 2 of Zr), the total moles have 0.3 mol% of Zr. The Al / Zr ratio in Comparative Example 2 is 3.33, which is less than 5. Figure 10 This is an SEM image of the surface of the secondary particles prepared in Comparative Example 2.

[0187] In Comparative Example 2, it was confirmed that due to the overgrowth of the primary particles, the initial charge and discharge capacities, efficiency, and cycle life characteristics were reduced.

[0188] Example 3

[0189] Manufacture a positive electrode active material and a rechargeable lithium battery cell in substantially the same manner as in Example 1, except that the positive electrode active material is prepared by changing the heat treatment temperature from 810 °C to 790 °C.

[0190] Figure 11 This is an SEM image of the surface of the secondary particles prepared in Example 3. The positive electrode active material in the form of individual particles is obtained by pulverizing the secondary particles with a jet mill.

[0191] Example 4

[0192] Manufacture a positive electrode active material and a rechargeable lithium battery cell in substantially the same manner as in Example 2, except that the positive electrode active material is prepared by changing the heat treatment temperature from 810 °C to 790 °C.

[0193] Figure 12 This is an SEM image of the surface of the secondary particles prepared in Example 4. The positive electrode active material in the form of individual particles is obtained by pulverizing the secondary particles with a jet mill.

[0194] Comparative Example 3

[0195] Manufacture a positive electrode active material and a rechargeable lithium battery cell in substantially the same manner as in Comparative Example 1, except that the positive electrode active material is prepared by changing the heat treatment temperature from 810 °C to 790 °C.

[0196] Figure 13 This is an SEM image of the surface of the secondary particles prepared in Comparative Example 3. In Comparative Example 3, under the heat treatment at 790 °C, the primary particles did not crystallize into a single crystal to a sufficient size, and the secondary particles were not pulverized into individual particles by the jet mill.

[0197] That of Comparative Example 3 Figure 13 with that of Example 3 Figure 11 and that of Example 4 Figure 12Comparison was made, and it was confirmed that by adding Al doped with Al and Zr in respective set or predetermined contents (e.g., amounts) under the same heat treatment temperature condition of 790 °C 2 O 3 and ZrO 2 , the grain growth was promoted, for example, the growth of primary particles or the growth of single crystals of primary particles.

[0198] Example 5

[0199] The positive electrode active material and the rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that the positive electrode active material was prepared by changing the heat treatment temperature from 810 °C to 890 °C.

[0200] Figure 14 is the SEM image of the surface of the secondary particles prepared in Example 5. The positive electrode active material in the form of single particles was obtained by pulverizing the secondary particles with a jet mill.

[0201] Example 6

[0202] The positive electrode active material and the rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 2, except that the positive electrode active material was prepared by changing the heat treatment temperature from 810 °C to 890 °C.

[0203] Figure 15 is the SEM image of the surface of the secondary particles prepared in Example 6. The positive electrode active material in the form of single particles was obtained by pulverizing the secondary particles with a jet mill.

[0204] Comparative Example 4

[0205] The positive electrode active material and the rechargeable lithium battery cell were manufactured in substantially the same manner as in Comparative Example 1, except that the positive electrode active material was prepared by changing the heat treatment temperature from 810 °C to 890 °C.

[0206] Figure 16 is the SEM image of the surface of the secondary particles prepared in Comparative Example 4. Even in Comparative Example 4, since the primary particles were not single-crystallized to a sufficient size under the heat treatment at 890 °C, the secondary particles were not pulverized by the jet mill.

[0207] Comparing that of Comparative Example 4 Figure 16 with that of Example 5 Figure 14 and that of Example 6 Figure 15 Comparison was made, and it was confirmed that by adding Al doped with Al and Zr in respective set or predetermined contents (e.g., amounts) under the same heat treatment temperature condition of 890 °C 2 O 3 and ZrO 2, which promotes grain growth, for example, the growth of primary particles or the growth of single crystals of primary particles.

[0208] Evaluation Example 1: Evaluation of cycle life characteristics

[0209] At 25 °C, the rechargeable lithium battery cells of Example 1, Example 2, and Comparative Example 1 were charged at a constant current of 0.2C to 4.45V and then charged at a constant voltage to 0.05C, and then discharged at 0.2C to 3.0V for initial charge and discharge. Subsequently, at 45 °C within the voltage range of 3.0V to 4.45V, the rechargeable lithium battery cells were charged and discharged at 1.0C for 30 cycles. Subsequently, the ratio of the discharge capacity of each cycle to the initial discharge capacity (i.e., the discharge capacity retention rate) is provided in Figure 17 . Refer to Figure 17 , as the cycles proceed, Comparative Example 1 in which the positive electrode active material did not crystallize into a sufficient size shows a sharp decline in the discharge capacity retention rate. In contrast, each of Example 1 and Example 2 achieved excellent or appropriate discharge capacity retention rates, i.e., cycle life characteristics at 45 °C.

[0210] As used herein, the terms "substantially", "about" and similar terms are used as approximate terms and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by a person of ordinary skill in the art. Also, as used herein, "about" or "approximate" also includes the recited value and means within an acceptable deviation range as determined by a person of ordinary skill in the art considering the measurement in question and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "about" may mean within one or more standard deviations of the recited value, or within ±30%, ±20%, ±10% or ±5% of the recited value.

[0211] In the context of the present disclosure and unless otherwise defined, the terms "use", "using" and "used" may be considered to be synonymous with the terms "utilize", "utilizing" and "utilized", respectively.

[0212] Any numerical range recited herein is intended to include all sub-ranges of the same numerical precision falling within the recited range. For example, a range of "1.0 to 10.0" is intended to include all sub-ranges between the recited minimum value of 1.0 and the recited maximum value of 10.0 (and including 1.0 and 10.0), i.e., all sub-ranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit recited herein is intended to include all lower numerical limits falling therein, and any minimum numerical limit recited in this specification is intended to include all higher numerical limits falling therein. Accordingly, the applicant reserves the right to amend this specification (including the claims) to expressly recite any sub-ranges falling within the ranges expressly recited herein.

[0213] The apparatus for preparing a positive electrode active material, battery management system (BMS) apparatus, and / or any other related apparatus or component described herein according to embodiments of the present invention may be implemented using any suitable hardware, firmware (e.g., application specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of the apparatus may be formed on one integrated circuit (IC) chip or on separate IC chips. Further, the various components of the apparatus may be implemented on a flexible printed circuit film, tape carrier package (TCP), or printed circuit board (PCB), or formed on a substrate. Further, the various components of the apparatus may be processes or threads running on one or more processors in one or more computing devices, executing computer program instructions, and interacting with other system components for performing the various functions described herein. The computer program instructions are stored in a memory, which may be implemented in a computing device using a standard storage device (such as, for example, random access memory (RAM)). The computer program instructions may also be stored in other non-transitory computer-readable media (such as, for example, CD-ROM, flash drive, etc.). And, those skilled in the art will recognize that, without departing from the scope of the present disclosure, the functions of various computing devices may be combined or integrated into a single computing device, or the functions of a particular computing device may be distributed over one or more other computing devices.

[0214] In view of the overall content of the present disclosure, those of ordinary skill in the art will recognize that each appropriate feature of the various embodiments of the present disclosure may be partially or fully combined or combined with each other, and may be interlocked and operated in various suitable ways, and each embodiment may be implemented independently of each other or in combination with each other in any suitable manner unless otherwise stated or implied.

[0215] Although the present disclosure has been described in connection with exemplary embodiments presently regarded as practical, it is to be understood that the present disclosure is not limited to the disclosed embodiments. On the contrary, the present disclosure is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the claims and their equivalents.

Claims

1. A positive electrode active material comprising: Layered lithium nickel composite oxides, in, The nickel content is greater than or equal to 60 mol%, based on 100 mol% of the total mole of metals other than lithium in the layered lithium nickel composite oxide. The aluminum content is 0.8 mol% to 1.5 mol% based on 100 mol% of the total mole of metals other than lithium in the layered lithium nickel-based composite oxide, and The zirconium content is 0.1 mol% to 0.3 mol% based on 100 mol% of the total mole of metals other than lithium in the layered lithium nickel composite oxide. in, The ratio of the aluminum content to the zirconium content Al / Zr is greater than or equal to 5, and in, The positive electrode active material has an average particle size D 50 It is in the form of single particles of 1 μm to 4 μm.

2. The positive electrode active material according to claim 1, wherein: The positive electrode active material is in the form of a single particle separated from another single particle or in the form of 2 to 9 single particles attached to each other.

3. The positive electrode active material according to claim 1, wherein: The layered lithium nickel composite oxide is represented by Chemical Formula 1: Chemical formula 1 He a1 We x1 M 1 y1 To z1 Zr w1 Oh 2-b1 X b1 , In Chemical Formula 1, 0.9≤a1≤1.2, 0.6≤x1≤0.991, 0≤y1≤0.391, 0.008≤z1≤0.015, 0.001≤w1≤0.003, 0.9≤x1+y1+z1+w1≤1.1, and 0≤b1≤0.1, M 1 is one or more elements selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W and Zn, and X is one or more elements selected from F, P and S.

4. A positive electrode comprising: a positive electrode current collector, and A positive electrode active material layer is located on the positive electrode current collector and includes the positive electrode active material according to any one of claims 1 to 3.

5. The positive electrode according to claim 4, wherein the positive electrode active material layer comprises: A first positive electrode active material comprising the positive electrode active material according to any one of claims 1 to 3, and a second positive electrode active material in the form of secondary particles, wherein each of the secondary particles comprises an aggregate of a plurality of primary particles, wherein the second positive electrode active material comprises a layered lithium nickel composite oxide, in, The nickel content is greater than or equal to 60 mol%, based on 100 mol% of the total mole of metals other than lithium in the layered lithium nickel composite oxide. The aluminum content is 0.8 mol% to 1.5 mol% based on 100 mol% of the total mole of metals other than lithium in the layered lithium nickel-based composite oxide, and The zirconium content is 0.1 mol% to 0.3 mol% based on 100 mol% of the total mole of metals other than lithium in the layered lithium nickel composite oxide. in, The ratio of the aluminum content to the zirconium content Al / Zr is greater than or equal to 5, and in, The secondary particles have a hollow structure with holes inside, and the average particle size D of the primary particles constituting the secondary particles is 50 1μm~4μm.

6. The positive electrode according to claim 5, wherein: The layered lithium nickel composite oxide of the second positive electrode active material is represented by Chemical Formula 1: Chemical formula 1 He a1 We x1 M 1 y1 To z1 Zr w1 Oh 2-b1 X b1 , In Chemical Formula 1, 0.9≤a1≤1.2, 0.6≤x1≤0.991, 0≤y1≤0.391, 0.008≤z1≤0.015, 0.001≤w1≤0.003, 0.9≤x1+y1+z1+w1≤1.1, and 0≤b1≤0.1, M 1 is one or more elements selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W and Zn, and X is one or more elements selected from F, P and S.

7. The positive electrode according to claim 5, wherein: The average particle size D of the secondary particles of the second positive electrode active material 50 It is 10μm~20μm.

8. The positive electrode according to claim 7, wherein: The size of the pores inside the secondary particles of the second positive electrode active material is 1 μm to 9 μm.

9. The positive electrode according to claim 5, wherein: The first positive electrode active material is included at 5 wt % to 60 wt % and the second positive electrode active material is included at 40 wt % to 95 wt % based on 100 wt % of the total weight of the first positive electrode active material and the second positive electrode active material.

10. A method for preparing a positive electrode active material, comprising: Ni precursor and M 1 A coprecipitation reaction of the precursors to prepare a nickel composite hydroxide in the form of particles having micropores inside the particles, A nickel-based composite hydroxide, a lithium raw material, an aluminum raw material, and a zirconium raw material are mixed and heat-treated to prepare hollow secondary particles including a layered lithium nickel-based composite oxide and having pores inside, as secondary particles made by aggregating a plurality of primary particles, and crushing the secondary particles to obtain a positive electrode active material, Among them, M 1 is one or more elements selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W and Zn, and Based on 100 mol% of the total mole of the metal of the nickel-based composite hydroxide, the aluminum in the aluminum raw material and the zirconium in the zirconium raw material, the aluminum content of the aluminum raw material is 0.8 mol% to 1.5 mol%, the zirconium content of the zirconium raw material is 0.1 mol% to 0.3 mol%, and the ratio of the aluminum content to the zirconium content Al / Zr is greater than or equal to 5.

11. The method according to claim 10, wherein: The coprecipitation reaction includes a first reaction at a pH ranging from 11 to 12, and a second reaction at a pH lower than that of the first reaction.

12. The method according to claim 10, wherein: The nickel composite hydroxide is represented by Chemical Formula 11: Chemical formula 11 No x11 M 1 y11 (OH)2, In Chemical Formula 11, 0.6≤x11≤1, 0≤y11≤0.4 and 0.9≤x11+y11≤1.1, and M 1 is one or more elements selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W and Zn, and wherein the nickel composite hydroxide is amorphous, and The nickel-based composite hydroxide is in the form of particles, and the particles include an inner portion including a plurality of micropores and an outer portion surrounding the inner portion and having a dense structure.

13. The method of claim 10, wherein: The lithium content of the lithium raw material is 0.9 to 1.2 parts by mole based on 1 part by mole of the total metal of the metal of the nickel composite hydroxide, the aluminum of the aluminum raw material, and the zirconium of the zirconium raw material, and The aluminum raw material is aluminum oxide, and The zirconium raw material is zirconium oxide.

14. The method of claim 10, wherein: The heat treatment is performed at 700° C. to 900° C. in an oxidizing gas atmosphere, and When the nickel-based composite hydroxide, the lithium raw material, the aluminum raw material, and the zirconium raw material are mixed and when the heat treatment is performed, no basic grain growth promoter is added.

15. The method of claim 10, wherein: The layered lithium nickel composite oxide is represented by Chemical Formula 1: Chemical formula 1 He a1 We x1 M 1 y1 To z1 Zr w1 Oh 2-b1 X b1 , In Chemical Formula 1, 0.9≤a1≤1.2, 0.6≤x1≤0.991, 0≤y1≤0.391, 0.008≤z1≤0.015, 0.001≤w1≤0.003, 0.9≤x1+y1+z1+w1≤1.1, and 0≤b1≤0.1, M 1 is one or more elements selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W and Zn, and X is one or more elements selected from F, P and S, and The average particle size D of the secondary particles 50 10μm to 20μm, and The average particle size D of the primary particles constituting the secondary particles 50 1μm to 4μm, and The size of the pores inside the secondary particles is 1 μm to 9 μm.

16. The method of claim 10, wherein: The secondary particles are crushed by a jet mill or an airflow classifying mill for 10 to 120 minutes, and The method comprises: A secondary heat treatment is performed after the secondary particles are pulverized, wherein the secondary heat treatment is performed at 500° C. to 900° C. in an oxidizing gas atmosphere.

17. The method according to claim 10, wherein the method comprises: The crushed secondary particles are mixed with the coating raw materials, After the crushed secondary particles and the coating raw material are mixed, a secondary heat treatment is performed, wherein the secondary heat treatment is performed at 500° C. to 900° C. in an oxidizing gas atmosphere, and The coating raw material is a raw material including one or more elements selected from Al, B, Co, Mg, V, Zn and Zr.

18. The method of claim 10, wherein: The obtained positive electrode active material includes an average particle size D 50 It is a single particle of 1μm to 4μm.

19. The method according to claim 10, wherein the positive electrode active material obtained comprises: Average particle size D 50 a first positive electrode active material in the form of a single particle of 1 μm to 4 μm, and a second positive electrode active material in the form of secondary particles each made by aggregating a plurality of primary particles, The average particle size D of the secondary particles of the second positive electrode active material is 50 is 10 μm to 20 μm, and the average particle size D of the primary particles constituting the secondary particles is 50 1μm~4μm.

20. A rechargeable lithium battery comprising: A positive electrode according to any one of claims 4 to 9 or a positive electrode comprising a positive electrode active material prepared by the method according to any one of claims 10 to 19, negative electrode, and Electrolyte.

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