Positive electrode active material, method of preparing positive electrode active material, positive electrode including positive electrode active material, and rechargeable lithium battery including positive electrode

Abstract

A positive electrode active material, a method of preparing the positive electrode active material, a positive electrode including the positive electrode active material, and a rechargeable lithium battery including the positive electrode are provided. The positive electrode active material includes a plurality of core particles and a coating layer on a surface of each of the plurality of core particles. The core particle includes a layered lithium nickel manganese-based composite oxide having a nickel content (e.g., an amount) of greater than or equal to about 60 mol% based on 100 mol% of a total amount of metal other than lithium in the layered lithium nickel manganese-based composite oxide. The coating includes Al and P.

Description

Technical Field

[0001] According to one or more embodiments, the present disclosure relates to a positive electrode active material, a method of preparing the positive electrode active material, 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 may use a rechargeable lithium battery having a relatively high energy density and relatively easy portability as a driving power source. Recently, research has been actively conducted to use a rechargeable lithium battery having a relatively high energy density as a driving power source for hybrid vehicles and / or electric vehicles, and / or as a power storage power source for home power storage (e.g., an energy storage system (ESS) or a power wall).

[0003] One or more suitable positive electrode active materials have been studied to realize or realize rechargeable lithium batteries for these applications. Among them, lithium nickel oxides, lithium nickel manganese cobalt composite oxides, lithium nickel cobalt aluminum composite oxides and lithium cobalt oxides are mainly used as positive electrode active materials. However, despite the recent increase in demand for large-size, high-capacity or high-energy-density rechargeable lithium batteries, the supply of positive electrode active materials including cobalt (a rare metal) is expected to be in serious shortage. For example, because cobalt is expensive and there are not many remaining reserves, it is desirable or necessary to develop a positive electrode active material that does not contain cobalt or reduces its content (e.g., amount). Summary of the invention

[0004] In one or more aspects of the present disclosure, as a positive electrode active material including a layered lithium nickel manganese composite oxide, by introducing an optimal or appropriate coating, the performance of a rechargeable lithium battery at high temperature and high voltage can be improved. For example, the capacity characteristics, initial charge / discharge efficiency (hereinafter, also referred to as efficiency) and high temperature cycle life characteristics of the rechargeable lithium battery can be improved.

[0005] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments.

[0006] In one or more embodiments, the positive electrode active material includes a plurality of core particles, which include a layered lithium nickel manganese composite oxide, the layered lithium nickel manganese composite oxide having a nickel content (e.g., amount) greater than or equal to about 60 mol% based on 100 mol% of the total metal amount other than lithium in the layered lithium nickel manganese composite oxide; and a coating located on the surface of each of the plurality of core particles and including Al and P.

[0007] In one or more embodiments, a method for preparing a positive electrode active material includes: (i) preparing a plurality of core particles, the plurality of core particles comprising a layered lithium nickel manganese composite oxide having a nickel content (e.g., amount) greater than or equal to about 60 mol% based on 100 mol% of the total metal amount other than lithium, (ii) adding an aluminum raw material to an aqueous solvent and mixing (e.g., mixing them) to prepare a coating solution, (iii) adding a plurality of core particles to the coating solution and mixing (e.g., mixing them) to prepare a first mixed solution, (iv) adding a phosphorus raw material to the first mixed solution and mixing (e.g., mixing them) to prepare a second mixed solution, (v) removing the aqueous solvent from the second mixed solution, drying the resulting product, and heat treating it to obtain a positive electrode active material.

[0008] In one or more embodiments, the positive electrode includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector, wherein the positive electrode active material layer includes the aforementioned positive electrode active material.

[0009] In one or more embodiments, a rechargeable lithium battery includes the aforementioned positive electrode, negative electrode, and electrolyte.

[0010] The positive electrode active material according to one or more embodiments maximizes capacity while minimizing or reducing production costs, ensures long cycle life, and improves high voltage and high temperature characteristics. A rechargeable lithium battery using the positive electrode active material can exhibit high initial charge / discharge capacity and efficiency, and can achieve excellent or appropriate high temperature cycle life characteristics and high temperature storage characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0012] Figure 5 This is a scanning electron microscope (SEM) image of the surface of the positive electrode active material of Example 3.

[0013] Figure 6 This is a SEM image of the surface of the positive electrode active material of Comparative Example 1.

[0014] Figure 7 This is a scanning electron microscope energy dispersive spectroscopy (SEM-EDS) image of the surface of the positive electrode active material of Example 3.

[0015] Figure 8 An image of each element is mapped for SEM-EDS analysis of the surface of the positive electrode active material according to Example 3.

[0016] Description of Reference Numerals

[0017] 100: Rechargeable lithium battery 10: Positive electrode

[0018] 11: Positive electrode lead lug 12: Positive electrode terminal

[0019] 20: Negative electrode 21: Negative electrode lead lug

[0020] 22: Negative electrode terminal 30: Separator

[0021] 40: electrode assembly 50: shell

[0022] 60: Sealing member 70: Electrode terminal piece

[0023] 71: Positive electrode terminal tab 72: Negative electrode terminal tab DETAILED DESCRIPTION

[0024] Hereinafter, specific embodiments will be described in more detail so that they can be easily implemented by those skilled in the art. Examples of embodiments are illustrated in the accompanying drawings, in which the same reference numerals refer to the same elements throughout, and a repeated description thereof may not be provided. Accordingly, embodiments are described only by reference to the drawings to explain aspects of the present description. However, the present disclosure may be embodied in many different forms and is not to be construed as being limited to the example embodiments set forth herein, but rather the present disclosure is limited by the scope of the claims.

[0025] The terms used herein are only used to describe the embodiments and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the singular expressions "a", "an" and "the" include plural expressions, including "at least one".

[0026] As used herein, "combinations thereof" refers to mixtures, laminates, composites, copolymers, alloys, blends, reaction products, and the like, of the components.

[0027] In this document, it should be understood that the use of terms such as “comprises,” “comprise,” “comprising,” “includes,” “include,” “including,” “having,” “has,” and / or “have” is intended to mark the presence of specified aspects, quantities, steps (e.g., actions or tasks), elements, and / or combinations thereof (e.g., any appropriate combination), but does not preclude the possibility of the presence or addition of one or more other features, quantities, steps (e.g., actions or tasks), elements, and / or combinations thereof (e.g., any appropriate combination).

[0028] In the accompanying drawings, for the sake of clarity, the thickness of layers, films, panels, regions, etc. is exaggerated, and the same reference numerals are used throughout to mark the same elements, and repeated descriptions thereof 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 (for example, when an element (such as a layer, film, region, or substrate) is referred to as being "on" another element), it may be directly on the other element, or there may also be intervening elements. In contrast, if an element is referred to as being "directly on" another element (for example, when an element is referred to as being "directly on" another element), there are no intervening elements.

[0029] In one or more embodiments, the “layer” herein includes not only a shape formed on the entire surface if viewed from a plan view (eg, a shape formed on the entire surface when viewed from a plan view) but also a shape formed on a partial surface.

[0030] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe one or more appropriate elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings set forth herein, a first element, component, region, layer or part described herein may be referred to as a second element, component, region, layer or part.

[0031] As utilized 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," if preceding a list of elements (e.g., when preceding a list of elements), modify the entire list of elements and do not modify the individual elements of the list. For example, the expressions "at least one of a through c" and "at least one of a, b, and c" may indicate only a, only b, only c, both a and b (e.g., both a and b), both a and c (e.g., both a and c), both b and c (e.g., both b and c), all of a, b, and c, or variations thereof.

[0032] Spatially relative terms, such as "below," "below," "below," "above," "on," and the like, may be used herein to easily describe the relationship of one element or feature to another element or feature. It will be understood that in addition to the orientations illustrated in the drawings, the spatially relative terms are also intended to encompass different orientations of the device in use or operation. For example, if the device in the drawings is turned over (e.g., when the device in the drawings is turned over), the elements described as "below" or "below" other elements or features will be oriented "above" the other elements or features. Thus, the example term "below" may encompass both orientations above and below (e.g., both orientations above and below at the same time). The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative terms utilized herein may be interpreted accordingly.

[0033] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present disclosure. Unless otherwise defined, all terms (including chemical terms, technical terms and scientific terms) used in the present disclosure have the same meaning as those commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It will be further understood that terms, such as those defined in common dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant field and the present disclosure, and will not be interpreted in an ideal or overly formal sense.

[0034] Example embodiments are described herein with reference to cross-sectional views of schematic diagrams as ideal embodiments. As such, variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances should be expected. Therefore, the embodiments described herein should not be construed as being limited to the specific shapes of the zones illustrated herein, but rather include deviations in shapes due to, for example, manufacturing. For example, a zone illustrated or described as flat may typically have rough and / or nonlinear features. Moreover, the illustrated sharp angles may be rounded. Therefore, the zones illustrated in the accompanying drawings are schematic in nature, and their shapes are not intended to illustrate the precise shapes of the zones, and are not intended to limit the scope of the claims.

[0035] The term "may" will be understood to refer to "one or more embodiments of the present disclosure," some of which include the described elements, and some of which do not include the elements and / or include alternative elements. Similarly, optional language such as "or" refers to "one or more embodiments of the present disclosure" that each include the corresponding enumerated items.

[0036] In this context, "consisting essentially of" means that any additional components will not substantially affect the chemical, physical, optical, or electrical properties of the semiconductor film.

[0037] Further, in this specification, the phrase “on a plane” or “plan view” indicates that a target portion is observed from the top, and the phrase “in a cross section” indicates that a cross section formed by vertically cutting the target portion is observed from the side.

[0038] In the context of this application and unless otherwise defined, the terms "use", "using" and "used" may be considered synonymous with the terms "utilize" or "utilization", "utilizing" and "utilized", respectively.

[0039] limited

[0040] As used herein, the term "particle size" refers to the average diameter of the particles if the particles are spherical (e.g., when the particles are spherical), and refers to the average major axis length of the particles if the particles are non-spherical (e.g., when the particles are non-spherical). For example, the average particle size can be measured by methods well suited to those skilled in the art (e.g., by a particle size analyzer, or by transmission electron microscopy or scanning electron microscopy images). In one or more embodiments, the average particle size value can be obtained by measuring using a dynamic light scattering method, performing data analysis, counting the number of particles in each particle size range, and calculating therefrom. Unless otherwise limited, the average particle size (D 50 ) may refer to the diameter of particles having a cumulative volume of 50% by volume in a particle size distribution. As used herein, if otherwise defined (e.g., when otherwise defined), the average particle size (D 50 ) refers to the diameter of particles accounting for 50% by volume of the cumulative volume in a particle size distribution obtained by randomly measuring the sizes (diameters or major axis lengths) of about 20 particles in a scanning electron microscope image.

[0041] In this document, the term "or" is not to be interpreted as exclusive, for example, "A or B" is interpreted to include A, B, A+B, etc.

[0042] In this document, the term "metal" is interpreted as a concept including ordinary metals, transition metals, and metalloids (semimetals).

[0043] Positive electrode active material

[0044] In one or more embodiments, the positive electrode active material includes: a plurality of core particles comprising a layered lithium nickel manganese composite oxide, the layered lithium nickel manganese composite oxide having a nickel content (e.g., amount) greater than or equal to about 60 mol% based on 100 mol% of the total metal amount other than lithium in the layered lithium nickel manganese composite oxide; and a coating located on the surface of each of the plurality of core particles and comprising Al and P.

[0045] Recently, due to the sharp rise in the price of cobalt (a rare metal), it is desirable or necessary to develop a positive electrode active material that does not contain (e.g., does not include) cobalt or reduces the cobalt content (e.g., amount). Among them, positive electrode active materials with olivine crystal structure (such as lithium iron phosphate (LFP), lithium manganese phosphate (LMP), lithium manganese iron phosphate (LMFP), etc.) or positive electrode active materials with spinel crystal structure (such as lithium manganese oxide (LMO), etc.), due to the small amount of lithium available in their structure, each may have limitations in achieving high capacity. The layered lithium nickel manganese positive electrode active material disclosed in the present invention has excellent or appropriate capacity and efficiency characteristics due to the large amount of lithium available in the structure, making it suitable as a material for high-capacity batteries. However, since the amount of cobalt as a component of the layered structure (e.g., a component that plays a key role in the layered structure) is reduced (e.g., partially removed), the structural stability is reduced, the resistance is increased, and it is difficult to achieve or ensure long cycle life characteristics. In one or more embodiments, the cobalt-free layered nickel manganese positive electrode active materials of the present disclosure may be associated with (e.g., significantly have such issues) accelerated side reactions with the electrolyte under high voltage and temperature conditions, resulting in increased gas generation and degraded cycle life characteristics.

[0046] In one or more embodiments, in order to improve the surface stability of the layered lithium nickel manganese positive electrode active material of the present disclosure (e.g., in the high voltage region), a coating comprising Al and P is included (e.g., introduced) to strengthen the particle surface of the active material. For example, forming a coating having a structural three-dimensional (3D) lithium channel improves the high voltage, high temperature cycle life characteristics and initial charge / discharge efficiency of a rechargeable lithium battery including a layered lithium nickel manganese positive electrode active material.

[0047] Nuclear particles

[0048] Core particles include layered lithium nickel manganese composite oxides. Based on 100mol% of the total metal amount other than lithium in layered lithium nickel manganese composite oxides, nickel content (e.g., amount) may be greater than or equal to about 60mol%, for example, about 60mol% to about 80mol%, about 65mol% to about 80mol%, about 70mol% to about 80mol%, about 60mol% to about 79mol%, about 60mol% to about 78mol% or about 60mol% to about 75mol%. If nickel content (e.g., amount) meets the disclosed range (e.g., when nickel content (e.g., amount) meets the disclosed range), even if cobalt content (e.g., amount) is reduced or cobalt is completely removed (e.g., when cobalt content (e.g., amount) is reduced or cobalt is completely removed), high capacity can be achieved and structural stability can be increased.

[0049] Based on 100mol% of the total metal amount other than lithium in the layered lithium nickel manganese composite oxide, the manganese content (e.g., amount) may be, for example, greater than or equal to about 15mol%, for example, about 15mol% to about 40mol%, about 15mol% to about 35mol%, about 15mol% to about 30mol% or about 20mol% to about 30%. If the manganese content (e.g., amount) satisfies the disclosed range (e.g., when the manganese content (e.g., amount) satisfies the disclosed range), the positive electrode active material can improve structural stability while achieving high capacity.

[0050] The layered lithium nickel manganese composite oxide may be a layered lithium nickel manganese aluminum composite oxide further including aluminum in addition to nickel and manganese. If the composite oxide contains aluminum (for example, when the composite oxide contains aluminum), even if the cobalt element is excluded from the structure (for example, when the cobalt element is excluded from the structure), it is also beneficial to maintain a stable layered structure. Based on 100 mol% of the total metal amount other than lithium in the lithium nickel manganese aluminum composite oxide, the aluminum content (for example, amount) may be greater than about 0 mol%, greater than or equal to about 0.1 mol%, greater than or equal to about 0.5 mol%, or greater than or equal to about 1 mol%, for example, greater than about 0 mol% and less than or equal to about 3 mol%, about 1 mol% to about 3 mol%, about 1 mol% to about 2.5 mol%, about 1 mol% to about 2 mol%, or about 1.5 mol% to about 2.5 mol%. If the aluminum content (e.g., amount) satisfies the disclosed range (e.g., when the aluminum content (e.g., amount) satisfies the disclosed range), a stable layered structure can be maintained even if cobalt is excluded (e.g., when cobalt is excluded), and structural collapse due to charging and discharging can be suppressed or reduced (e.g., the problem of structural collapse due to charging and discharging), and long cycle life characteristics of the positive electrode active material can be achieved or implemented.

[0051] According to one or more embodiments, the concentration of aluminum in the core particle may be substantially uniform. For example, there may be a concentration gradient of aluminum from the center of the core particle to the surface of the core particle in each of the core particles. In some embodiments, the aluminum concentration inside the core particle may be neither higher nor lower than any other part (e.g., the outer part) of the core particle, so that the aluminum in the core particle can be evenly distributed. For example, a structure as described herein can be obtained by using an aluminum raw material during precursor production without additionally doping aluminum during the synthesis of the core particle, thereby using nickel-manganese-aluminum hydroxide as a precursor to synthesize a composite oxide. In some embodiments, the core particle may be in the form of a secondary particle in which a plurality of primary particles are aggregated (e.g., a plurality of secondary particles are each an aggregate of a plurality of primary particles), and for example, regardless of the position of the primary particles, the aluminum content (e.g., amount) inside the primary particles may each be substantially the same (or similar). For example, if a primary particle is selected at a random position (e.g., in a cross section of a secondary particle) and the aluminum content (e.g., amount) is measured inside the primary particle instead of at the interface of the primary particle (e.g., when a primary particle is selected at a random position (e.g., in a cross section of a secondary particle) and the aluminum content (e.g., amount) is measured inside the primary particle instead of at the interface of the primary particle), the aluminum content (e.g., amount) may be substantially the same (e.g., similar or uniform). For example, regardless of the position of the primary particle (i.e., regardless of whether the primary particle is close to the surface or the center of the secondary particle, the aluminum content may be substantially the same (e.g., similar or uniform)). In this structure, even if cobalt is not present or is present in a very small amount (e.g., when cobalt is not present or is present in a very small amount), a stable layered structure may be maintained, and aluminum byproducts or aluminum aggregates may not be generated, thereby simultaneously improving the capacity, efficiency, and cycle life characteristics of the positive electrode active material.

[0052] The layered lithium nickel manganese-based composite oxide may be represented by Chemical Formula 1.

[0053] Chemical formula 1

[0054] Li a1 Ni x1 Mn y1 Al z1 M 1 w1 O 2-b1 X b1

[0055] In Chemical Formula 1, 0.9≤a1≤1.8, 0.6≤x1≤0.8, 0.1≤y1≤0.4, 0≤z1≤0.03, 0≤w1≤0.3, 0.9≤x1+y1+z1+w1≤1.1, and 0≤b1≤0.1. In Chemical Formula 1, M 1may be at least one (e.g., one or more) element selected from B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zr, and X may be at least one (e.g., one or more) element selected from F, P, and S.

[0056] In Chemical Formula 1 according to one or more embodiments, 0.9 ≤ a1 ≤ 1.5, or 0.9 ≤ a1 ≤ 1.2. Additionally, Chemical Formula 1 may contain aluminum, where the case where 0.6 ≤ x1 ≤ 0.8, 0.1 ≤ y1 ≤ 0.39, 0.01 ≤ z1 ≤ 0.03, and 0 ≤ w1 ≤ 0.29 may be satisfied, or, for example, the case where 0.6 ≤ x1 ≤ 0.8, 0.1 ≤ y1 ≤ 0.39, 0.01 < z1 ≤ 0.03, and 0 ≤ w1 ≤ 0.29 may be satisfied.

[0057] For example, in Chemical Formula 1, 0.6 ≤ x1 ≤ 0.79, 0.6 ≤ x1 ≤ 0.78, 0.6 ≤ x1 ≤ 0.75, 0.65 ≤ x1 ≤ 0.8, or 0.7 ≤ x1 ≤ 0.79; 0.1 ≤ y1 ≤ 0.35, 0.1 ≤ y1 ≤ 0.30, 0.1 ≤ y1 ≤ 0.29, 0.15 ≤ y1 ≤ 0.39, or 0.2 ≤ y1 ≤ 0.3; 0.01 ≤ z1 ≤ 0.025, 0.01 < z1 ≤ 0.02, or 0.01 < z1 ≤ 0.019; and 0 ≤ w1 ≤ 0.28, 0 ≤ w1 ≤ 0.27, 0 ≤ w1 ≤ 0.26, 0 ≤ w1 ≤ 0.25, 0 ≤ w1 ≤ 0.24, 0 ≤ w1 ≤ 0.23, 0 ≤ w1 ≤ 0.22, 0 ≤ w1 ≤ 0.21, 0 ≤ w1 ≤ 0.2, 0 ≤ w1 ≤ 0.15, 0 ≤ w1 ≤ 0.1, or 0 ≤ w1 ≤ 0.09.

[0058] For example, the layered lithium nickel manganese composite oxide may exclude (e.g., not include or contain) cobalt or may include (e.g., contain) a small amount of cobalt. For example, based on the total metal amount other than lithium in 100 mol% of the layered lithium nickel manganese composite oxide, the cobalt content (e.g., amount) may be about 0 mol% to about 0.01 mol%.

[0059] The core particles may be in the form of secondary particles made by aggregating a plurality of primary particles. For example, each secondary particle may be an aggregate of a plurality of primary particles. The shape of the secondary particles may be spherical, elliptical, polyhedral, or irregular, and the primary particles may be spherical, elliptical, plate-like, and / or a combination thereof (e.g., any suitable combination).

[0060] The core particles may be chemically reactive with components in the electrolyte (e.g., susceptible to chemical attack). For example, if the battery is operated at high voltage or high temperature conditions (e.g., when the battery is operated at high voltage or high temperature conditions), more side reactions with the electrolyte may occur, resulting in an increase in the amount of gas generated, which may deteriorate the cycle life and safety of the battery. However, these potential problems may be addressed by including (e.g., introducing) a coating according to one or more embodiments as described in more detail elsewhere herein on the core particles.

[0061] coating

[0062] The positive electrode active material according to one or more embodiments includes a coating layer located on the surface of the core particle and including Al and P. The coating layer can improve the structural stability of the core particle (e.g., including a layered lithium nickel manganese composite oxide) and effectively inhibit or reduce the side reaction of the positive electrode active material with the electrolyte. The coating layer can also promote the conduction of lithium ions and reduce resistance, thereby increasing the initial discharge capacity and initial charge / discharge efficiency of the rechargeable lithium battery, while (e.g., simultaneously) improving high temperature cycle life characteristics and high temperature storage characteristics.

[0063] In the coating, the presence of Al and P can be checked and determined by characterization analysis (such as scanning electron microscope energy dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), etc.). The coating may include, for example, at least one (e.g., one or more) selected from PO bonds, P=O bonds, Al-O bonds, Al=O bonds, and PO-Al bonds. The coating may include, for example, aluminum phosphate. In addition to aluminum phosphate (e.g., AlPO 4 ), the coating may further include aluminum oxide (e.g., Al 2 O 3 ), lithium aluminum oxide (e.g., LiAlO 2 ) and / or combinations thereof. For example, the coating may include lithium aluminum oxide and aluminum phosphate, for example, LiAlO 2 and AlPO 4 .

[0064] In one or more embodiments, the positive electrode active material may include a first coating layer and a second coating layer located on the surface of the core particle. The first coating layer may include aluminum oxide and the second coating layer is located on the first coating layer and includes aluminum phosphate. For example, the positive electrode active material may include a coating layer having a double-layer structure. The first coating layer may include aluminum oxide, lithium aluminum oxide, and / or a combination thereof (e.g., any suitable combination), for example, LiAlO 2 The second coating may include (eg, contain) both Al and P (eg, simultaneously), for example, the second coating may include AlPO 4 .

[0065] In one or more embodiments, according to the method for manufacturing a positive electrode active material as described in more detail elsewhere herein, an Al coating step (e.g., an action or task) may be first performed by adding the core particles to an aluminum-containing coating solution and mixing them (e.g., the core particles and the aluminum-containing coating solution) to form an Al coating, and then a phosphorus-based coating raw material is added thereto to form a P coating on the Al coating. Accordingly, the method may provide a positive electrode active material having a first coating layer including Al or aluminum oxide on the core particles and a second coating layer disposed on the first coating layer and including P and aluminum phosphate. Unlike one or more embodiments, for example, if P is coated first (e.g., when P is coated first), PO 4 3- ions can interact with the Li + ions react to form lithium phosphate (such as Li 3 PO 4 etc.), resulting in structural changes on the surface of the positive electrode active material and reducing the reversible capacity. However, if the first coating and the second coating are performed (e.g., layered) in an order according to one or more embodiments (e.g., when the first coating and the second coating are performed (e.g., layered) in an order according to one or more embodiments), the structural stability of the core particles can be further enhanced. For example, the conduction of lithium ions can be increased or promoted, so that the resistance is reduced, thereby increasing the reversible capacity (e.g., of a rechargeable lithium battery) and improving the cycle life characteristics and high temperature characteristics. According to the method of one or more embodiments, the positive electrode active material may include aluminum oxide, lithium aluminum oxide, aluminum phosphate and / or a combination thereof (e.g., any suitable combination) on the surface, but lithium phosphate may be excluded (e.g., not included).

[0066] Based on 100 mol% of the total amount of elements other than lithium and oxygen in the positive electrode active material, the Al content (e.g., amount) in the coating layer may be about 0.5 mol% to about 3 mol%, for example, about 0.5 mol% to about 2.5 mol%, about 0.5 mol% to about 2 mol%, or about 0.5 mol% to about 1.5 mol%. In one or more embodiments, based on 100 mol% of the total amount of elements other than lithium and oxygen in the positive electrode active material, the P content (e.g., amount) in the coating layer may be about 0.1 mol% to about 2 mol%, for example, about 0.1 mol% to about 1.5 mol%, about 0.1 mol% to about 1 mol%, about 0.1 mol% to about 0.9 mol%, or about 0.1 mol% to about 0.5 mol%. If the Al content (e.g., amount) and the P content (e.g., amount) each satisfy the disclosed ranges, respectively (e.g., when the Al content (e.g., amount) and the P content (e.g., amount) each satisfy the disclosed ranges, respectively), the structural stability of the layered lithium nickel manganese composite oxide is improved and the conduction of lithium ions is promoted, thereby simultaneously (e.g., synchronously) improving the initial discharge capacity, initial charge / discharge efficiency, high temperature cycle life characteristics, and high temperature storage characteristics of the rechargeable lithium battery.

[0067] In one or more embodiments, the Al content (e.g., amount) may be about 5 at% to about 35 at%, for example, about 5 at% to about 30 at%, about 5 at% to about 25 at%, about 6 at% to about 20 at%, or about 7 at% to about 15 at%, based on 100 at% of the total elements other than lithium on the surface of the positive electrode active material as measured by scanning electron microscope energy dispersive spectroscopy (SEM-EDS). In one or more embodiments, the P content (e.g., amount) may be about 0.1 at% to about 8 at%, for example, about 0.5 at% to about 7 at%, about 2 at% to about 6 at%, or about 2 at% to about 5 at%, based on 100 at% of the total elements other than lithium on the surface of the positive electrode active material as measured by SEM-EDS. The total elements (e.g., the total elements measured on the surface of the positive electrode active material) may, for example, be selected from Li, Ni, Mn, Al, Ti, O, and C. If the Al content (e.g., amount) and the P content (e.g., amount) on the surface of the positive electrode active material each satisfy the disclosed range (e.g., when the Al content (e.g., amount) and the P content (e.g., amount) on the surface of the positive electrode active material each satisfy the disclosed range), the initial charge / discharge capacity, initial charge / discharge efficiency, high temperature cycle life characteristics, and high temperature storage characteristics of a rechargeable lithium battery using the positive electrode active material can be improved simultaneously (e.g., synchronously).

[0068] On the surface of the positive electrode active material, the ratio (Al / P) of the Al content (e.g., amount) to the P content (e.g., amount) may be or satisfy a ratio of about 2 or more, for example, about 2 to about 10, about 2 to about 8, about 2 to about 6, about 2 to about 4, or about 2 to about 3. If the disclosed ratio is satisfied (e.g., when the disclosed ratio is satisfied), the initial charge / discharge capacity, initial charge / discharge efficiency, high temperature cycle life, and high temperature storage characteristics of the rechargeable lithium battery may be improved simultaneously (e.g., synchronously).

[0069] The coating according to one or more embodiments may be in the form of a film around the surface of each of the plurality of core particles (e.g., continuously surrounding the surface of each of the plurality of core particles), for example, it may be in the form of a shell around the entire surface of each of the plurality of core particles (e.g., continuously surrounding the entire surface of each of the plurality of core particles). This may be different from (e.g., different from) a structure in which only a portion of the surface of each of the plurality of core particles is partially coated. According to one or more embodiments, the coating may be formed to completely cover the surface of the core particles, and may be formed to be very thin and substantially uniform in thickness. For example, the positive electrode active material may not increase resistance or reduce capacity, improve structural stability, effectively inhibit side reactions with the electrolyte, reduce the amount of gas generated under high voltage and high temperature conditions, and achieve long cycle life characteristics.

[0070] The coating may have a thickness of about 5 nanometers (nm) to about 500 nm, for example, about 5 nm to about 400 nm, about 5 nm to about 300 nm, about 5 nm to about 200 nm, about 5 nm to about 100 nm, or about 10 nm to about 50 nm. If the coating is within the thickness range or satisfies the thickness range (for example, when the coating is within the thickness range or satisfies the thickness range), the structural stability of the positive electrode active material can be improved without increasing (for example, caused by or due to the coating) resistance or reducing (for example, caused by or due to the coating) capacity, and the side reaction with the electrolyte can be effectively suppressed or reduced. The thickness of the coating can be measured by, for example, scanning electron microscopy (SEM), transmission electron microscopy (TEM), time-of-flight secondary ion mass spectrometry (TOF-SIMS), XPS or energy dispersive spectroscopy (EDS) analysis, for example, the thickness of the coating can be measured by EDS line profile analysis of a cross section of the positive electrode active material.

[0071] The coating according to one or more embodiments may be thin and the thickness may be substantially uniform, at the level of a few nanometers to hundreds of nanometers. For example, the deviation of the coating thickness in a positive electrode active material particle may be less than or equal to about 20%, less than or equal to about 18%, or less than or equal to about 15%. In this article, the deviation of the coating thickness refers to the deviation of the coating thickness in a positive electrode active material particle. For example, the thickness of about 10 points in the electron microscope image of the cross section of a single positive electrode active material particle can be measured to calculate the arithmetic mean, and then the absolute value of the difference between one measurement data and the arithmetic mean is divided by the arithmetic mean and multiplied by 100% to calculate the deviation of the coating thickness. The fact that the deviation or standard deviation of the coating thickness meets the disclosed range indicates that a coating with substantially uniform thickness is formed in the form of a good or appropriate film on the surface of the positive electrode active material particle. That is, the fact that the deviation or standard deviation of the coating thickness meets the range disclosed above indicates that a coating with substantially uniform thickness on the surface of the core particle of the positive electrode active material is effectively formed as a high-quality film. Accordingly, the structural stability of the positive electrode active material is improved, the side reaction with the electrolyte can be effectively suppressed or reduced, and the resistance increase or capacity reduction due to the coating layer can be minimized or reduced.

[0072] In addition to aluminum, the coating may further contain nickel, manganese, and / or combinations thereof (eg, any suitable combination).

[0073] The average particle size (D 50 ), but can be, for example, about 1 micrometer (μm) to about 25 μm, about 5 μm to about 25 μm, about 10 μm to about 25 μm, about 11 μm to about 20 μm, or about 12 μm to about 18 μm. As used herein, if no limitation is otherwise provided (e.g., when no limitation is otherwise provided), the average particle size (D 50 ) refers to the diameter of particles with a cumulative volume of 50% by volume in a particle size distribution obtained by randomly measuring the size (diameter or length of the major axis) of about 20 particles in a scanning electron microscope image of the positive electrode active material. If the average particle size of the positive electrode active material satisfies the disclosed range (for example, when the average particle size of the positive electrode active material satisfies the disclosed range), high capacity and long cycle life can be achieved, and it can be beneficial to form a coating according to one or more embodiments.

[0074] In addition, in one or more embodiments, the positive electrode active material (or another positive electrode active material) may not contain sodium. Generally speaking, sodium ions can be used in the preparation process of the positive electrode active material, but according to the preparation method described in more detail elsewhere in this article, core particles having a stable structure and a coating layer with substantially uniform thickness can be formed without using sodium ions.

[0075] In one or more embodiments, the positive electrode active material according to one or more embodiments may contain a sulfur (S) component on the surface, which may be caused by a coating material as described in more detail elsewhere herein.

[0076] Method for preparing positive electrode active material

[0077] In one or more embodiments, the method for preparing a positive electrode active material includes: (i) preparing a plurality of core particles, which include a layered lithium nickel manganese composite oxide, based on 100 mol% of the total metal amount other than lithium in the layered lithium nickel manganese composite oxide, the layered lithium nickel manganese composite oxide has a nickel content (e.g., amount) greater than or equal to about 60 mol%, (ii) adding an aluminum raw material to an aqueous solvent and mixing them (e.g., an aluminum raw material and an aqueous solvent) to prepare a coating solution, (iii) adding a plurality of core particles to the coating solution and mixing them (e.g., a plurality of core particles and a coating solution) to prepare a first mixed solution, (iv) adding a phosphorus raw material to the first mixed solution and mixing them (e.g., a phosphorus raw material and a first mixed solution) to prepare a second mixed solution, and (v) removing the aqueous solvent from the second mixed solution, drying the resulting product, and heat treating the resulting product to obtain a positive electrode active material. The aforementioned positive electrode active material can be prepared by the method described herein.

[0078] The layered lithium nickel-manganese composite oxide can be prepared, for example, by mixing a layered nickel-manganese hydroxide and a lithium raw material and performing a first heat treatment. The nickel-manganese composite hydroxide can be a precursor of a core particle, and can be in the form of a secondary particle in which a plurality of primary particles are aggregated, for example, each secondary particle is an aggregate of a plurality of primary particles. The nickel-manganese composite hydroxide can be prepared by a commonly used coprecipitation method.

[0079] Based on 100mol% of the total metal amount in the nickel-manganese composite hydroxide, the nickel content (e.g., amount) may be or satisfy greater than or equal to about 60mol%, and may be, for example, about 60mol% to about 80mol%, about 65mol% to about 80mol%, about 70mol% to about 80mol%, about 60mol% to about 79mol%, about 60mol% to about 78mol% or about 60mol% to about 75mol%. For example, if the nickel content (e.g., amount) satisfies the described range (e.g., when the nickel content (e.g., amount) satisfies the described range), even if the cobalt content (e.g., amount) is reduced (e.g., when the cobalt content (e.g., amount) is reduced), high capacity can be achieved and structural stability can be increased.

[0080] Based on 100 mol % of the total metal amount in the nickel-manganese composite hydroxide, the manganese content (e.g., amount) may be greater than or equal to about 15 mol %, for example, about 15 mol % to about 40 mol %, about 15 mol % to about 39 mol %, or about 15 mol % to about 35 mol %, about 15 mol % to about 30 mol %, about 20 mol % to about 30 mol %, etc.

[0081] In one or more embodiments, if the nickel-manganese composite hydroxide further contains aluminum (for example, when the nickel-manganese composite hydroxide further contains aluminum), based on 100 mol% of the total metal amount in the nickel-manganese composite hydroxide, the aluminum content (for example, amount) may be greater than or equal to about 0.1 mol%, greater than or equal to about 0.5 mol%, or greater than or equal to about 1 mol%, for example, about 1 mol% to about 3 mol%, about 1 mol% to about 2.5 mol%, about 1 mol% to about 2 mol%, or about 1 mol% to about 1.9 mol%. If the manganese and aluminum contents (for example, amounts) of the nickel-manganese composite hydroxide meet the disclosed ranges (for example, when the manganese and aluminum contents (for example, amounts) of the nickel-manganese composite hydroxide meet the disclosed ranges), high capacity can be achieved, while the structural stability of the positive electrode active material can be increased, and the production price can be reduced to increase economic efficiency.

[0082] In the method for preparing a positive electrode active material according to one or more embodiments, when preparing the core particles, aluminum may not be additionally doped, but an aluminum raw material may be used to prepare a precursor, so that a nickel-manganese-aluminum composite hydroxide in which aluminum is uniformly (e.g., substantially uniformly) dispersed in the structure may be used as a precursor. If such a precursor is used (e.g., when such a precursor is used), although cobalt is not included, the positive electrode active material may also stably maintain a layered structure after repeated charging and discharging, and may not form aluminum byproducts or aluminum aggregates, thereby improving the capacity and efficiency characteristics and cycle life characteristics of the positive electrode active material.

[0083] Based on 100 mol% of the total metal amount in the nickel-manganese composite hydroxide, the cobalt content (e.g., amount) in the nickel-manganese composite hydroxide may be less than or equal to about 0.01 mol%, less than or equal to about 0.005 mol%, or less than or equal to about 0.001 mol%. The nickel-manganese composite hydroxide may be economical because it avoids the increase in unit cost caused by cobalt, maximizes capacity, and improves structural stability.

[0084] For example, the nickel-manganese-based composite hydroxide can be represented by Chemical Formula 2.

[0085] Chemical formula 2

[0086] Ni x2 Mn y2 Al z2 M 2 w2 (OH) 2

[0087] In Chemical Formula 2, 0.6≤x2≤0.8, 0.1≤y2≤0.4, 0≤z2≤0.03, 0≤w2≤0.3, and 0.9≤x2+y2+z2+w2≤1.1, and M 2 It may be at least one (e.g., one or more) element selected from B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zr.

[0088] For example, in Chemical Formula 2, 0.6≤x2≤0.8, 0.1≤y2≤0.39, 0.01≤z2≤0.03, and 0≤w2≤0.29.

[0089] The nickel-manganese composite hydroxide may be in the form of particles, and the average particle size (D 50 ) may be about 1 μm to about 25 μm, about 5 μm to about 20 μm, about 10 μm to about 20 μm, about 11 μm to about 18 μm, or about 12 μm to about 15 μm.

[0090] The nickel-manganese composite hydroxide and the lithium raw material can be mixed in a molar ratio of about 1:0.9 to about 1:1.8, for example, about 1:0.9 to about 1:1.5 or about 1:0.9 to about 1:1.2. For example, the first heat treatment can be carried out in an oxygen atmosphere at a temperature range of about 750°C to about 950°C, about 780°C to about 900°C, or about 810°C to about 890°C for about 2 hours to about 20 hours or about 4 hours to about 12 hours. The layered lithium nickel-manganese composite oxide can be obtained by heat treatment. The obtained composite oxide may be substantially the same as the oxide (e.g., composite oxide) described herein for the core particles in the positive electrode active material.

[0091] Because the layered lithium nickel manganese composite oxide can have significantly different residual lithium contents (e.g., amounts) on the particle surface and different one or more appropriate properties with oxides having different compositions (e.g., lithium nickel cobalt manganese composite oxides, lithium nickel cobalt aluminum composite oxides, lithium cobalt oxides, etc.), it may be impractical (e.g., almost impossible) to form a satisfactory coating in the form of a uniform film using conventional coating methods. In one or more embodiments, a method for coating the surface of the layered lithium nickel manganese composite oxide particles with Al and P each in a substantially very uniform thickness is considered or proposed. In one or more embodiments, a method for applying a coating of aluminum (Al) and phosphorus (P) to the surface of the layered lithium nickel manganese composite oxide particles is contemplated, ensuring a substantially uniform thickness overall.

[0092] In one or more embodiments, the coating solution is first prepared by adding an aluminum raw material to an aqueous solvent and mixing them (e.g., an aluminum raw material and an aqueous solvent), and then adding the core particles to the coating solution and mixing. This can be considered a salt solution wet coating method and can be referred to as a "pre-addition method", in which the salt as the coating raw material is first completely dissolved, and then the core particles of the positive electrode active material are added.

[0093] The aqueous solvent may include distilled water, an alcohol solvent, and / or combinations thereof (eg, any suitable combination).

[0094] The aluminum raw material may be aluminum sulfate. Aluminum sulfate may be considered or referred to as the best or appropriate raw material for forming a substantially uniform Al coating on the layered lithium nickel manganese-based composite oxide.

[0095] The Al content (e.g., amount) in the aluminum raw material may be (e.g., designed to be) about 0.1 mol% to about 3.0 mol%, for example, about 0.1 mol% to about 2.0 mol%, about 0.5 mol% to about 1.5 mol%, about 0.5 mol% to about 3 mol%, about 0.6 mol% to about 1.4 mol%, about 0.7 mol% to about 1.3 mol%, or about 0.8 mol% to about 1.2 mol%, based on 100 mol% of all elements except lithium and oxygen in the core particles and the total amount of aluminum of the aluminum raw material. If the Al content (e.g., amount) (e.g., designed) is within the disclosed range (e.g., when the Al content (e.g., amount) (e.g., designed) is within the disclosed range), the coating layer can be formed to have a thin and substantially uniform thickness of several nanometers to hundreds of nanometers, reducing the amount of gas generated by the rechargeable lithium battery under high voltage or high temperature operating conditions, and improving high capacity and long cycle life characteristics. For example, if the aluminum coating content falls within the specified range (e.g., when the aluminum coating content falls within the specified range), the resulting coating achieves a thin and substantially uniform thickness in the range of several nanometers to hundreds of nanometers. This helps to reduce the gas generated by rechargeable lithium batteries under high voltage or high temperature conditions, thereby enhancing their capacity and extending their cycle life.

[0096] The aluminum raw material is added and mixed into the aqueous solvent for about 1 minute to about 60 minutes, for example, about 1 minute to about 30 minutes, about 3 minutes to about 30 minutes or about 5 minutes to about 10 minutes. In addition, the mixing speed may be about 100rpm to about 800rpm, for example, about 200rpm to about 600rpm or about 250rpm to about 500rpm. Under these conditions, the aluminum raw material can be completely dissolved in the aqueous solvent to obtain a colorless and transparent coating solution, and the coating solution can be used to effectively form a substantially uniform coating according to one or more embodiments. When the core particles are added to the prepared coating solution, the core particles can be added thereto to increase the coating quality while stirring the coating solution.

[0097] In one or more embodiments, the pH of the coating solution is 1.5 to 4, and the amount of time spent adding the core particles to the coating solution may be about 30 seconds per about 500 grams (g) to about 2 minutes per about 500g, for example, about 30 seconds per about 500g to about 1.5 minutes per about 500g, etc. The time or speed of adding the core particles can be appropriately or suitably adjusted to control the pH of the supernatant after the coating is completed, so as to induce the effective formation of a substantially uniform coating according to one or more embodiments. If the time or speed of adding the core particles is too slow (for example, when the time or speed of adding the core particles is too slow), the reaction rate of each particle can be changed, and a substantially uniform coating may not be formed. In addition, if the time or speed of adding the core particles is too fast (for example, when the time or speed of adding the core particles is too fast), the pH can change rapidly, and a substantially uniform coating may not be formed.

[0098] After the whole amount of core particles are added to the coating solution, stirring can be carried out (i.e., the mixing time can be) about 15 minutes to about 60 minutes, for example, about 20 minutes to about 50 minutes or about 30 minutes to about 45 minutes. From the beginning of adding the core particles to the coating solution to the time required or consumed for completing stirring, the time for preparing the first mixed solution can be adjusted in about 1 hour.

[0099] In one or more embodiments, if the core particles are added to the coating solution and mixing is stopped (e.g., when the core particles are added to the coating solution and mixing is stopped), that is, the pH range of the first mixed solution may be about 5.5 to about 8.5. If the pH of the first mixed solution is less than 5.5 (e.g., when the pH of the first mixed solution is less than 5.5), the acidity may become strong and a substantially uniform coating may not be formed, and if the pH is greater than 8.5 (e.g., when the pH is greater than 8.5), the alkalinity may become strong, making it difficult to form a substantially uniform Al coating.

[0100] In step (eg, action or task) (iv), a phosphorus-based raw material may be added to the first mixed solution and then mixed to perform P coating. In this context, the phosphorus-based raw material may be, for example, phosphoric acid (H 3 PO 4 ). In one or more embodiments, in step (e.g., action or task) (iii), the core particles may be added to the Al coating solution and then mixed to perform Al coating, and then, in step (e.g., action or task) (iv), the phosphorus raw material may be added thereto and then mixed to guide or perform P coating toward or on the outermost surface of the positive electrode active material. As described herein, unlike one or more embodiments, for example, if P is coated first (e.g., when P is coated first), PO 4 3-ions can interact with the Li + ions react to form lithium phosphate (such as Li 3 PO 4 The P coating is performed after the Al coating according to one or more embodiments (e.g., when the P coating is performed after the Al coating according to one or more embodiments), the structural stability of the core particles can be further enhanced, and the conduction of lithium ions can be promoted, and the electrical (electronic) resistance can be reduced, thereby increasing the reversible capacity and improving the cycle life characteristics and high temperature characteristics.

[0101] According to the manufacturing method according to one or more embodiments, a first coating layer including aluminum oxide, lithium aluminum oxide, and / or a combination thereof (e.g., any appropriate combination) may be formed, and on the first coating layer, a second coating layer including aluminum phosphate may be formed. Aluminum oxide, etc. of the first coating layer and aluminum phosphate of the second coating layer may not be well mixed but exist as separate layers, and in one or more embodiments, phosphate in the form of anions may not be substantially or substantially diffused into the core particles but may exist on the outermost surface of the positive electrode active material.

[0102] The phosphorus content (e.g., amount) of the phosphorus-based raw material may be 0.1 mol% to 2 mol%, for example, 0.1 mol% to 1.5 mol%, 0.1 mol% to 1 mol%, 0.1 mol% to 0.9 mol%, or 0.1 mol% to 0.5 mol%, based on 100 mol% of the total amount of all elements except lithium and oxygen in the core particles and the phosphorus of the phosphorus-based raw material. If the P coating content (e.g., amount) (e.g., designed to) is within the described range (e.g., when the P coating content (e.g., amount) (e.g., designed to) is within the described range), a coating having a thin and substantially uniform thickness of several nanometers to hundreds of nanometers may be formed, cycle life characteristics are improved, and the initial charge / discharge efficiency under high voltage and high temperature driving conditions is simultaneously (e.g., synchronously) enhanced.

[0103] After the phosphorus raw material is added to the first mixed solution, mixing may be performed (i.e., the mixing time may be) for about 15 minutes to about 60 minutes, for example, about 20 minutes to about 50 minutes or about 30 minutes to about 45 minutes. The amount of time desired or required to prepare the second mixed solution may be appropriately or suitably adjusted within about 1 hour. In one or more embodiments, if a phosphorus raw material (e.g., phosphoric acid) is added to the first mixed solution (e.g., when the phosphorus raw material (e.g., phosphoric acid) is added to the first mixed solution), the pH may be reduced and become acidic, then the pH is increased again, and if the mixing is completed (e.g., when the mixing is completed), the pH of the second mixed solution may be in the range of about 5.5 to about 8.5. If the pH of the second mixed solution is less than about 5.5 (e.g., when the pH of the second mixed solution is less than about 5.5), a substantially uniform coating may not be formed due to strong acidity, and if the pH is greater than about 8.5 (e.g., when the pH is greater than about 8.5), a substantially uniform coating may also be difficult to form due to strong alkalinity.

[0104] After removing the aqueous solvent from the second mixed solution, the (e.g., obtained) product thus obtained can be, for example, dried at about 40°C to about 240°C, about 100°C to about 220°C, or about 150°C to about 200°C and under, for example, vacuum conditions, and a satisfactory coating product can be obtained under these conditions.

[0105] The resulting product after removing the aqueous solvent from the mixed solution and drying can be referred to as a coating product. The coating product includes a plurality of core particles and a coating including Al and P on the surface of each of the plurality of core particles. For example, the coating including Al and P may include a fiber shape (e.g., in the form of a fiber), for example, in the form of a grid or a spider web. Such a grid may be continuously formed over the entire surface of the core particle. The grid-like coating may be very thin and substantially uniform in thickness around the core particle (e.g., completely around the core particle) to strengthen the surface of the positive electrode active material and improve structural stability, thereby enhancing high temperature and high voltage characteristics.

[0106] After mixing the nickel-manganese-based composite hydroxide and the lithium raw material, heat treatment of the mixture may be referred to as a first heat treatment, and heat treatment of the coated product may be referred to as a second heat treatment (eg, secondary heat treatment).

[0107] In one or more embodiments, the second heat treatment temperature range may be about 730°C to about 800°C, for example, about 740°C to about 800°C, about 750°C to about 800°C, about 750°C to about 780°C, or about 750°C to about 775°C. If the second heat treatment temperature is set to the disclosed range (for example, when the second heat treatment temperature is set to the disclosed range), the tendency of aluminum to diffuse into the secondary particles can be reduced, and the aluminum can be mainly retained on the surface of the secondary particles. At present, the surface of the secondary particles can be coated in the form of a shell with a very thin and uniform (for example, substantially uniform) thickness, and the P element can also be well coated on the surface of the secondary particles.

[0108] If the second heat treatment temperature exceeds about 800° C. (for example, when the second heat treatment temperature exceeds about 800° C.), the tendency of aluminum to diffuse into the secondary particles may increase, making it difficult to form a high-concentration Al-rich coating on the surface, and accordingly, the initial charge / discharge capacity and efficiency characteristics at high voltage may be reduced, and the cycle life characteristics at high voltage and high temperature may be reduced. If the second heat treatment temperature is less than about 730° C. (for example, when the second heat treatment temperature is less than about 730° C.), a portion of the aluminum or phosphorus components may aggregate (for example, agglomerate) or may be substantially non-uniformly distributed on the surface of the secondary particles, which may result in reduced cycle life characteristics under high temperature and high voltage conditions and low initial charge / discharge efficiency.

[0109] For example, the second heat treatment may be performed in the oxygen atmosphere for about 2 to about 20 hours or about 3 to about 10 hours.

[0110] The obtained positive electrode active material includes a plurality of core particles including a layered lithium nickel manganese-based composite oxide having a nickel content (e.g., amount) of greater than or equal to about 60 mol% based on 100 mol% of the total metal amount other than lithium in the layered lithium nickel manganese-based composite oxide; and a coating layer located on the surface of each of the plurality of core particles and including Al and P. In some embodiments, the coating layer may include layered aluminum oxide and aluminum phosphate.

[0111] Positive electrode

[0112] In one or more embodiments, the positive electrode includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector, wherein the positive electrode active material layer includes the aforementioned positive electrode active material. In addition to the aforementioned positive electrode active material, the positive electrode active material layer may further include other types (kinds) of positive electrode active materials. In addition, 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).

[0113] According to one or more embodiments, the loading level of the positive electrode active material layer may be about 10 mg / cm 2 )~about 40mg / cm 2 , for example, about 10 mg / cm 2 ~about 30mg / cm 2 or about 10 mg / cm 2 ~about 20mg / cm 2 . In addition, the density of the positive electrode active material layer in the final pressed positive electrode may be about 3.3 grams per cubic centimeter (g / cc) to about 3.7 g / cc, for example, about 3.3 g / cc to about 3.6 g / cc or about 3.4 g / cc to about 3.58 g / cc. If a positive electrode active material according to one or more embodiments is applied (for example, when a positive electrode active material according to one or more embodiments is applied), it is advantageous to achieve a loading level and density of such a positive electrode active material, and a positive electrode that satisfies a loading level and density of a positive electrode active material within the disclosed range is suitable for realizing a high-capacity, high-energy-density rechargeable lithium battery.

[0114] Binder

[0115] The binder can improve the bonding properties of the positive electrode active material particles to each other and / or the bonding properties 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, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth) acrylated styrene-butadiene rubber, epoxy resin, (meth) acrylic resin, polyester resin and nylon, but are not limited thereto.

[0116] Conductive Materials

[0117] 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 carbon-based materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.); metal-based materials including metal powders or metal fibers of copper, nickel, aluminum, silver, etc.; conductive polymers (such as polyphenylene derivatives); and / or mixtures thereof (e.g., any appropriate mixture).

[0118] Each content (eg, amount) of the binder and the conductive material may be about 0.5 wt % to about 5 wt % based on 100 wt % of the positive electrode active material layer.

[0119] The positive electrode current collector may include an Al foil, but the present disclosure is not limited thereto.

[0120] Rechargeable lithium battery

[0121] 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.

[0122] For example, rechargeable lithium batteries may be classified into cylindrical batteries, prismatic batteries, pouch batteries, coin batteries, etc., depending on the shape. Figure 1 to Figure 4 is a schematic diagram showing a rechargeable lithium battery according to one or more embodiments, wherein Figure 1 A cylindrical battery is shown, Figure 2 A prismatic cell is shown, and Figure 3 and Figure 4 A pouch cell is shown. Figure 1 to Figure 4 , the rechargeable lithium battery 100 includes an electrode assembly 40 and a case 50 in which the electrode assembly 40 is accommodated, and the electrode assembly 40 has a separator 30 interposed between a positive electrode 10 and a negative electrode 20. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte. Figure 1 As shown in FIG. 1 , the rechargeable lithium battery 100 may include a sealing member 60 that seals the housing 50. Figure 2 In the embodiment, 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. Figure 3 and Figure 4 As shown in FIG. 1 , the rechargeable lithium battery 100 includes electrode tabs, namely, a positive electrode tab 71 and a negative electrode tab 72, or an electrode tab 130, which respectively serve as electrical paths for guiding current formed in the electrode assembly 40 to the outside.

[0123] The rechargeable lithium battery according to one or more embodiments may be rechargeable at a high voltage, or may be suitable for driving at a high voltage. For example, the charging voltage of the rechargeable lithium battery may be greater than or equal to about 4.45V, about 4.45V to about 4.7V, about 4.45V to about 4.6V, or about 4.45V to about 4.55V, etc. By applying the positive electrode active material according to one or more embodiments, the rechargeable lithium battery can significantly reduce the amount of gas generated even when charged at a high voltage (for example, when charged at a high voltage), and can achieve high capacity and long cycle life characteristics.

[0124] Negative electrode

[0125] The negative electrode may include a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector and including a negative electrode active material, and the negative electrode active material layer may further include a binder, a conductive material, and / or a combination thereof (e.g., any suitable combination).

[0126] Negative electrode active material

[0127] 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, or a transition metal oxide.

[0128] The material that reversibly intercalates / deintercalates lithium ions may include, for example, crystalline carbon, amorphous carbon, and / or a combination thereof (e.g., any suitable combination) as a carbon-based negative electrode active material. The crystalline carbon may be amorphous, or natural graphite or artificial graphite in the form of flakes, sheets, spheres, or fibers (e.g., in the form of fibers). The amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbonization product, calcined coke, etc.

[0129] The lithium metal alloy includes an alloy of lithium and at least one (e.g., one or more) metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0130] The material capable of doping / dedoping lithium may be a Si-based negative electrode active material or a Sn-based negative electrode active material. The Si-based negative electrode active material may include silicon, a silicon-carbon composite, SiO x (0 < x ≤ 2), a Si-Q alloy (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 a combination thereof (e.g., any suitable combination), such as Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, and / or a combination thereof (e.g., any suitable combination)) and / or a combination thereof (e.g., any suitable combination). The Sn-based negative electrode active material may be Sn, SnO x (0 < x ≤ 2) (e.g., SnO 2 ), a Sn alloy, and / or a combination thereof (e.g., any suitable combination).

[0131] The silicon-carbon composite may be a composite of silicon and amorphous carbon. The average particle size (D50 ) can be, for example, from about 0.5 μm to about 20 μm. According to 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, the silicon-carbon composite can include (e.g., each) secondary particle (core) (e.g., a plurality of secondary particles (cores)) that aggregates primary silicon particles and an amorphous carbon coating (shell) on the surface of the secondary particle. Amorphous carbon can also be present between the primary silicon particles. For example, the primary silicon particles can be coated with amorphous carbon. The secondary particles can be dispersed in the amorphous carbon matrix (can be present in the amorphous carbon matrix).

[0132] 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 or hard carbon, mesophase pitch carbonized product, and calcined coke.

[0133] 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 content (e.g., amount) of silicon can be from about 10 wt% to about 50 wt%, and the content (e.g., amount) of amorphous carbon can be from about 50 wt% to about 90 wt%. In one or more embodiments, 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 content (e.g., amount) of silicon can be from about 10 wt% to about 50 wt%, the content (e.g., amount) of crystalline carbon can be from about 10 wt% to about 70 wt%, and the content (e.g., amount) of amorphous carbon can be from about 20 wt% to about 40 wt%.

[0134] In addition, the thickness of the amorphous carbon coating can be from about 5 nanometers (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). In some embodiments, 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 (e.g., when) no other definition is provided otherwise, the average particle size (D 50 ) indicates the diameter of the particles in which the cumulative volume in the particle size distribution is about 50 volume%.

[0135] The Si-based negative electrode active material or the Sn-based negative electrode active material may be mixed with the carbon-based negative electrode active material. If the Si-based negative electrode active material or the Sn-based negative electrode active material and the carbon-based negative electrode active material are mixed and used (for example, when the Si-based negative electrode active material or the Sn-based negative electrode active material and the carbon-based negative electrode active material are mixed and used), the mixing ratio may be about 1:99 to about 90:10 by weight.

[0136] Binder

[0137] The binder is used to bind the negative electrode active material particles well to each other and also to bind 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 (eg, any appropriate combination).

[0138] 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 combinations thereof (eg, any suitable combination).

[0139] The aqueous binder may include styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol and / or combinations thereof (e.g., any suitable combination).

[0140] If an aqueous binder is used as a binder in the negative electrode active material layer (for example, when an aqueous binder is used as a binder in the negative electrode active material layer), a cellulose compound capable of imparting viscosity may be further included. As the cellulose compound, one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose and alkali metal salts thereof may be mixed and used. The alkali metal may be Na, K or Li.

[0141] The dry binder may be a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and / or combinations thereof (eg, any appropriate combination).

[0142] Conductive Materials

[0143] A conductive material (e.g., an electronic conductor) is included 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 include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metal-based materials including metal powders or metal fibers of copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; and / or mixtures thereof (e.g., any appropriate mixture).

[0144] Based on 100wt% of the negative electrode active material layer, the content (e.g., amount) of the negative electrode active material may be about 95wt% to about 99.5wt%, and based on 100wt% of the negative electrode active material layer, the content (e.g., amount) of the binder may be about 0.5wt% to about 5wt%. For example, the negative electrode active material layer may include about 90wt% to about 99wt% of the negative electrode active material, about 0.5wt% to about 5wt% of the binder, and about 0.5wt% to about 5wt% of the conductive material.

[0145] Negative electrode current collector

[0146] The negative electrode current collector may 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) or an alloy thereof, and may be in the form of foil, sheet or foam. The thickness of the negative electrode current collector may 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.

[0147] Electrolyte

[0148] For example, the electrolyte for a rechargeable lithium battery may be an electrolyte that may include a non-aqueous organic solvent and a lithium salt.

[0149] The non-aqueous organic solvent is used as a medium for transporting ions participating in the electrochemical reaction of the battery. The non-aqueous organic solvent may include carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents and / or combinations thereof (eg, any appropriate combination).

[0150] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), ethyl methyl 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, decanoic acid lactone, mevalonate lactone, 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. In one or more embodiments, 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, a branched hydrocarbon group or a cyclic hydrocarbon group, and may include a double bond, an aromatic ring or an ether bond, etc.); amides (such as, dimethylformamide); dioxolanes (such as, 1,3-dioxolane, 1,4-dioxolane, etc.); cyclopentane sulfone, etc.

[0151] The non-aqueous organic solvent may be used alone or as a mixture of two or more types (kinds), and if used as a mixture of two or more types (kinds) (for example, when used as a mixture of two or more types (kinds)), the mixing ratio may be appropriately or suitably adjusted according to the desired or appropriate battery performance, which is widely known to those skilled in the art.

[0152] If a carbonate-based solvent is used (eg, when a carbonate-based solvent is used), a cyclic carbonate and a chain carbonate may be mixed and used, and the cyclic carbonate and the chain carbonate may be mixed in a volume ratio of about 1:1 to about 1:9.

[0153] The non-aqueous organic solvent may further include an aromatic hydrocarbon organic solvent. For example, a carbonate-based solvent and an aromatic hydrocarbon organic solvent may be mixed and used in a volume ratio of about 1:1 to about 30:1.

[0154] The electrolyte may further include vinyl ethylene carbonate, vinylene carbonate or ethylene carbonate-based compounds to improve the battery cycle life.

[0155] Examples of the ethylene carbonate-based compound may include fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, and cyanoethylene carbonate.

[0156] The lithium salt dissolved in the organic solvent supplies lithium ions in the battery, ensures the basic operation of the rechargeable lithium battery, and improves the transport of lithium ions between the positive electrode and the negative electrode. Examples of the lithium salt may include a 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 )(wherein x and y are integers of 1 to 20), at least one of lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFBOP) and lithium bis(oxalato)borate (LiBOB).

[0157] The concentration of the lithium salt may be in the range of about 0.1 M to about 2.0 M. If the concentration of the lithium salt is within the disclosed range (e.g., when the concentration of the lithium salt is within the disclosed range), the electrolyte has appropriate or suitable ion conductivity and viscosity, and thus excellent or suitable performance may be achieved, and lithium ions may be efficiently moved.

[0158] Diaphragm

[0159] Depending on the type or kind of rechargeable lithium battery, the separator may be present between the positive electrode and the negative electrode. The separator may include a polyethylene separator, a polypropylene separator, a polyvinylidene fluoride separator, or a multilayer film of two or more layers thereof, and a mixed multilayer film such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, a polypropylene / polyethylene / polypropylene three-layer separator, etc.

[0160] The separator may include a porous substrate and a coating on one surface or both surfaces (eg, opposite surfaces) of the porous substrate, the coating including an organic material, an inorganic material, and / or a combination thereof (eg, any suitable combination).

[0161] The porous substrate may be a polymer film formed by any one polymer selected from polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyether ketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, and polytetrafluoroethylene (e.g., Teflon), or copolymers or mixtures of two or more thereof.

[0162] 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.

[0163] The organic material may include a (meth)acryl-based copolymer, which includes a first structural unit and a second structural unit, the first structural unit is derived from (meth)acrylamide, and the second structural unit includes at least one of a structural unit derived from (meth)acrylic acid or (meth)acrylate and a structural unit derived from (meth)acrylamide sulfonic acid or its salt.

[0164] The inorganic material may include a 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 (eg, any suitable combination), but the present disclosure is not limited thereto. The average particle size (D 50 ) may be from about 1 nm to about 2000 nm, for example, from about 100 nm to about 1000 nm or from about 100 nm to about 700 nm.

[0165] The organic material and the inorganic material may be mixed in one coating layer, or may exist in the form of a stack of a coating layer including an organic material and a coating layer including an inorganic material.

[0166] The coating layer may have a thickness of 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.

[0167] Terms such as "substantially," "about," and "approximately" are used as relative terms and not as terms of degree, and are intended to take into account the inherent deviations in measurements or calculations that one of ordinary skill in the art will recognize. They may include deviations from the stated value and an acceptable range determined by one of ordinary skill in the art, taking into account the limitations and errors associated with the measurement of that quantity. For example, "about" may refer to one or more standard deviations of the stated value, or ±30%, ±20%, ±10%, or ±5% of the stated value.

[0168] The numerical ranges disclosed herein include and are intended to disclose all sub-ranges of the same numerical precision. For example, a range of "1.0 to 10.0" is intended to include 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. Therefore, the applicant reserves the right to amend this specification (including the claims) to explicitly set forth any sub-ranges contained within the ranges explicitly set forth herein.

[0169] Examples and comparative examples of the present disclosure are described in more detail herein.However, the following examples are merely examples of one or more embodiments of the present disclosure, and the present disclosure is not limited to the following examples.

[0170] Example

[0171] Example 1

[0172] 1. Preparation of positive electrode active material

[0173] Ni 0.75 Mn 0.24 Al 0.01 (OH) 2 and LiOH in a molar ratio of 1:1.05, and then subjected to a first heat treatment at 845° C. in an oxygen atmosphere for 8 hours to prepare a layered lithium nickel manganese-based composite oxide in the form of secondary particles having Li 1.05 Ni 0.75 Mn 0.24 Al 0.01 O 2 composition and an average particle size (D 50 ).

[0174] A coating solution is prepared by adding aluminum sulfate and 600g of distilled water to a 1L reactor, and then stirring the mixture at about 350rpm for about 5 minutes to dissolve the aluminum sulfate. When the aluminum sulfate is completely dissolved, the coating solution is checked to be colorless and transparent. Subsequently, within 1.5 minutes, while stirring, 500g of layered lithium nickel manganese composite oxide is added to the coating solution, and then stirring is maintained for about 30 minutes to prepare a first mixed solution. In this article, the aluminum content (e.g., amount) of aluminum sulfate is designed to be 1mol% based on 100mol% of all elements except lithium and oxygen in the final positive electrode active material. After completing the stirring, it is confirmed that the pH of the first mixed solution is 6.6. Subsequently, H 3 PO 4 Add to the first mixed solution, and then continue stirring for 30 minutes to prepare a second mixed solution. Based on 100 mol% of all elements except lithium and oxygen in the final positive electrode active material, the P content (e.g., amount) of phosphoric acid is designed to be 0.1 mol%. The pH of the solution decreases due to the addition of phosphoric acid, and increases again after stirring, and then remains at about 6.6.

[0175] Subsequently, the solvent was removed from the second mixed solution using an aspirator and a filter press, and vacuum dried at 190° C. to obtain a coated product. Subsequently, the solvent was extracted from the second mixed solution using an aspirator and a filter press to obtain an intermediate product. The intermediate product was then vacuum dried at 190° C. to obtain a coated product.

[0176] The coated product was secondarily heat-treated at 750° C. for 8 hours under an oxygen atmosphere to obtain a final positive electrode active material.

[0177] 2. Manufacturing of coin battery cells

[0178] 98.5wt% of the positive electrode active material, 1.0wt% of the polyvinylidene fluoride binder and 0.5wt% of the carbon nanotube conductive material were mixed to prepare a positive electrode active material layer slurry, and the slurry was coated on an aluminum foil current collector, then dried and pressed to manufacture a positive electrode. In this article, the loading level of the positive electrode active material layer was 10 mg / cm 2 ), and the density of the positive electrode active material layer in the final pressed positive electrode was about 3.4 grams per cubic centimeter (g / cc).

[0179] The positive electrode is used with lithium metal as the counter electrode and a polytetrafluoroethylene separator, and in one or more embodiments, a 1M LiPF 6 The electrolyte prepared by dissolving in a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 3:7 was used to manufacture a coin cell in a conventional method.

[0180] Example 2

[0181] A positive electrode active material and a coin cell were manufactured in substantially the same manner as in Example 1, except that the P content of phosphoric acid was changed to 0.3 mol % based on 100 wt % of all elements except lithium and oxygen in the final positive electrode active material.

[0182] Example 3

[0183] A positive electrode active material and a coin cell were manufactured in substantially the same manner as in Example 1, except that the P content (eg, amount) of phosphoric acid was changed to 0.5 mol % based on 100 wt % of all elements except lithium and oxygen in the final positive electrode active material.

[0184] Comparative Example 1

[0185] A positive electrode active material and a coin cell were manufactured in substantially the same manner as in Example 1, except that the layered lithium nickel manganese-based composite oxide itself (ie, without the Al coating layer and the P coating layer) was used as the positive electrode active material.

[0186] Comparative Example 2

[0187] A positive electrode active material and a coin cell were manufactured in substantially the same manner as in Example 1, except that the positive electrode active material was prepared by Al coating alone without P coating, ie, filtering and drying the first mixed solution, and then performing the second heat treatment.

[0188] Evaluation Example 1: SEM-EDS Analysis

[0189] Figure 5 is a SEM image of the surface of the positive electrode active material of Example 3, and Figure 6 This is a SEM image of the surface of the positive electrode active material of Comparative Example 1. Figure 5 and Figure 6 , one type or kind of network coating shape was observed on the surface of the positive electrode active material of Example 3.

[0190] In one or more embodiments, the surface of the positive electrode active material of Example 3 is subjected to SEM-EDS analysis to obtain Figure 7 The detection intensity diagram of each C element, O element, Mn element, Ni element, Al element and P element is provided in Figure 8 SEM images (upper left) and mapping images of each C, O, Al, Mn, Ni, and P element are provided in the reference Figure 7 , both the Al element and the P element are detected on the surface of the positive electrode active material (eg, simultaneously), and referring to Figure 8, both the Al element and the P element are (eg, simultaneously) very uniformly (eg, substantially uniformly) distributed on the surface of the positive electrode active material.

[0191] In addition, the content (e.g., amount) of each element on the surface of the positive electrode active material of Example 3 calculated by SEM-EDS analysis is shown in Table 1. Table 1 shows the content (e.g., amount) of each element based on 100 at% of the total amount of elements other than lithium (i.e., C+O+Al+P+Mn+Ni) on the surface of the positive electrode active material.

[0192] Table 1

[0193] element Content (at%) C 6.92 O 57.38 Al 7.82 P 3.46 Mn 7.81 Ni 16.61

[0194] Referring to Table 1, based on the total amount of elements other than lithium on the surface of the positive electrode active material of Example 3, the Al content (e.g., amount) is 7.82at%, based on all elements other than lithium on the surface of the positive electrode active material of Example 3, the P content (e.g., amount) is 3.46at%, and the Al / P content (e.g., amount) ratio is about 2.26.

[0195] Evaluation Example 2: Evaluation of initial charge capacity / initial discharge capacity and efficiency of coin cell

[0196] The coin cell cells of Examples 1 to 3 and Comparative Examples 1 to 2 were charged to an upper voltage limit of 4.45V at a constant current of 0.2C at 25°C, and charged to 0.05C at a constant voltage, and then discharged to a cutoff voltage of 3.0V at 0.2C for initial charge and discharge. In Table 2, the initial charge capacity (i.e., "0.2C charge" in Table 2), the initial discharge capacity (i.e., "0.2C discharge" in Table 2), and the efficiency as a ratio of the initial discharge capacity to the initial charge capacity are provided.

[0197] Evaluation Example 3: Evaluation of high temperature cycle life characteristics

[0198] After Evaluation Example 2, the coin cell was repeatedly charged and discharged 50 times or more at 1.0C within a voltage range of 3.0V to 4.45V at 45°C to calculate the ratio of the 50th cycle discharge capacity to the initial discharge capacity, which is shown in Table 2 as the high temperature cycle life.

[0199] Evaluation Example 4: Evaluation of high temperature storage characteristics

[0200] The coin cell initially charged to 4.45 V in Evaluation Example 1 was stored at 90° C. for 4 hours, and then the amount of gas generated in the coin cell was measured, and the results are shown in Table 2 (ie, “High Temperature Storage Gas Generation”).

[0201] Table 2

[0202]

[0203] Referring to Table 2, compared with Comparative Examples 1 and 2, if stored at high temperature (e.g., when stored at high temperature), Examples 1 to 3 exhibit improved initial discharge capacity, increased initial charge / discharge efficiency, significantly improved high temperature cycle life characteristics, and significantly reduced amount of generated gas.

[0204] The device for preparing positive electrode active materials according to the embodiments of the present disclosure described herein, the battery management system (BMS) device and / or any other related device or component can be implemented using any appropriate hardware, firmware (e.g., a dedicated integrated circuit), software, or a combination of software, firmware, and hardware. For example, the components of the device may be formed on an integrated circuit (IC) chip or on a separate IC chip. Further, the components of the device may be implemented on a flexible printed circuit film, a tape carrier package (TCP), or a printed circuit board (PCB), or formed on a substrate. Further, the components of the device may be processes or threads running on one or more processors in one or more computing devices, which execute computer program instructions and interact with other system components to perform 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, a random access memory (RAM). Computer program instructions may also be stored in other non-transient computer-readable media (such as, for example, CD-ROMs, flash drives, etc.). Furthermore, those skilled in the art will recognize that the functionality of computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the scope of the present disclosure.

[0205] In view of the overall content of the present disclosure, a person skilled in the art will recognize that each appropriate feature of the various embodiments of the present disclosure may be partially or completely combined or combined with each other, and may be technically interlocked and operated in various appropriate ways, and unless otherwise described or implied, each embodiment may be implemented independently of each other or in combination with each other in any appropriate manner.

[0206] Although the present disclosure has been described in conjunction with what are currently considered to be practical example embodiments, it should be understood that the present disclosure should not be limited to the disclosed embodiments. Instead, 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: a plurality of core particles comprising a layered lithium nickel manganese-based composite oxide having a nickel content of greater than or equal to 60 mol % based on 100 mol % of the total metal content excluding lithium in the layered lithium nickel manganese-based composite oxide; and A coating layer is on a surface of each of the plurality of core particles and includes Al and P.

2. The positive electrode active material according to claim 1, wherein The coating includes aluminum phosphate.

3. The positive electrode active material according to claim 2, wherein The coating further comprises aluminum oxide, lithium aluminum oxide, and / or combinations thereof.

4. The positive electrode active material according to claim 1, wherein The positive electrode active material includes a first coating layer on a surface of each of the plurality of core particles and including aluminum oxide, lithium aluminum oxide, and / or a combination thereof, and a second coating layer on the first coating layer and including aluminum phosphate.

5. The positive electrode active material according to claim 1, wherein The amount of Al in the coating layer is 0.5 mol% to 3 mol% based on 100 mol% of the total amount of elements excluding lithium and oxygen in the positive electrode active material, and The amount of P in the coating layer is 0.1 mol% to 2 mol% based on 100 mol% of the total amount of elements excluding lithium and oxygen in the positive electrode active material.

6. The positive electrode active material according to claim 1, wherein The amount of Al is 5 to 35 at% and the amount of P is 0.1 to 8 at% based on 100 at% of the total amount of elements other than lithium on the surface of the positive electrode active material as measured by scanning electron microscope energy dispersive spectroscopy, and On the surface of the positive electrode active material, a ratio of the Al amount to the P amount (Al / P) is greater than or equal to 2.

7. The positive electrode active material according to claim 1, wherein The coating is in the form of a shell around the surface of each of the core particles, The coating has a thickness of 5 nm to 500 nm, and The deviation of the thickness of the coating layer in one positive electrode active material particle is less than or equal to 20%.

8. The positive electrode active material according to claim 1, wherein In the layered lithium nickel manganese composite oxide of the plurality of core particles, based on 100 mol% of the total metal amount excluding lithium in the layered lithium nickel manganese composite oxide, the amount of nickel is 60 mol% to 80 mol%, the amount of manganese is greater than or equal to 15 mol% and the amount of cobalt is 0 mol% to 0.01 mol%, and The layered lithium nickel manganese composite oxide of the plurality of core particles further includes aluminum, and the amount of aluminum in the plurality of core particles is greater than 0 mol % and less than or equal to 3 mol % based on 100 mol % of the total metal amount excluding lithium in the layered lithium nickel manganese composite oxide.

9. The positive electrode active material according to claim 1, wherein The layered lithium nickel manganese-based composite oxide of the plurality of core particles is a positive electrode active material represented by Chemical Formula 1: Chemical formula 1 Li a1 Ni x1 Mr y1 Al z1 M 1 w1 O 2-b1 X b1 , Wherein in Chemical Formula 1, 0.9≤a1≤1.8， 0.6≤x1≤0.8， 0.1≤y1≤0.4， 0≤z1≤0.03， 0≤w1≤0.3， 0.9≤x1+y1+z1+w1≤1.1, and 0≤b1≤0.1， M 1 is at least one element selected from the group consisting of B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y and Zr, and X is at least one element selected from F, P and S.

10. The positive electrode active material according to claim 1, wherein Each of the plurality of core particles is in the form of a secondary particle, each of the secondary particles is an aggregate of a plurality of primary particles, and The average particle size D of the secondary particles of the positive electrode active material 50 It is 10μm~25μm.

11. A method for preparing a positive electrode active material according to any one of claims 1 to 10, comprising: preparing a plurality of core particles comprising a layered lithium nickel manganese-based composite oxide having a nickel content of greater than or equal to 60 mol % based on 100 mol % of the total metal content excluding lithium in the layered lithium nickel manganese-based composite oxide, An aluminum raw material is added to an aqueous solvent and mixed to prepare a coating solution, adding the plurality of core particles to the coating solution and mixing to prepare a first mixed solution, adding a phosphorus raw material to the first mixed solution and mixing to prepare a second mixed solution, and The aqueous solvent is removed from the second mixed solution, the resultant product is dried, and the resultant product is heat-treated to obtain the positive electrode active material.

12. The method according to claim 11, wherein In the layered lithium nickel manganese composite oxide, based on 100 mol% of the total metal amount except lithium, the nickel amount is 60 mol% to 80 mol%, the manganese amount is greater than or equal to 15 mol%, the aluminum amount is 0 mol% to 3 mol%, and the cobalt amount is 0 mol% to 0.01 mol%.

13. The method according to claim 11, wherein The aluminum raw material is aluminum sulfate, and The phosphorus raw material is phosphoric acid, wherein the amount of aluminum in the aluminum raw material is 0.5 mol% to 3 mol% based on 100 mol% of the total amount of all elements except lithium and oxygen in the core particles and the aluminum in the aluminum raw material, and The phosphorus content of the phosphorus-based raw material is 0.1 mol% to 2 mol% based on 100 mol% of the total amount of all elements except lithium and oxygen in the core particles and phosphorus of the phosphorus-based raw material.

14. The method according to claim 11, wherein The pH of the coating solution is 1.5 to 4, The time required for adding the plurality of core particles to the coating solution is 30 seconds per 500 g to 2 minutes per 500 g, The mixing time after adding the plurality of core particles to the coating solution is 15 minutes to 60 minutes, and The pH of the first mixed solution is 5.5-8.

5.

15. The method according to claim 11, wherein The mixing time after adding the phosphorus raw material to the first mixed solution is 15 minutes to 60 minutes, and The pH of the second mixed solution is 5.5-8.

5.

16. The method according to claim 11, wherein removing the aqueous solvent from the second mixed solution and drying the resulting product at 40° C. to 240° C. under vacuum conditions, and The heat treatment is performed at 730°C to 800°C.

17. The method according to claim 11, wherein obtaining a coated product by removing the aqueous solvent from the second mixed solution and drying the resulting product, The coated product includes a plurality of core particles and a coating layer on a surface of each of the plurality of core particles, and The coating includes Al and P and is in the form of a grid or spider web.

18. A positive electrode comprising: a positive electrode current collector, and a positive electrode active material layer on the positive electrode current collector, The positive electrode active material layer comprises the positive electrode active material according to any one of claims 1 to 10 or the positive electrode active material prepared by the method according to any one of claims 11 to 17.

19. The positive electrode according to claim 18, wherein The positive electrode active material layer has a 10 mg / cm 2 ~40mg / cm 2 The load level, and The positive electrode active material layer has a density of 3.3 g / cc to 3.7 g / cc.

20. A rechargeable lithium battery comprising: The positive electrode according to claim 18 or 19, negative electrode, and Electrolyte, The charging voltage of the rechargeable lithium battery is greater than or equal to 4.45V.

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