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

Abstract

The application 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. The positive electrode active material may include: a core particle including a layered lithium nickel-based composite oxide and having a single particle shape; and a coating layer provided on a surface of the core particle and comprising cobalt and / or zirconium; wherein the lithium nickel-based composite oxide of the particles includes aluminum and zirconium, a nickel content (e.g., an amount) of greater than or equal to about 60 mol%, an aluminum content (e.g., an amount) of about 0.8 mol% to about 1.5 mol%, and a zirconium content (e.g., an amount) of about 0.1 mol% to about 0.3 mol%, based on 100 mol% of total metals other than lithium.

Description

Technical Field

[0001] One or more embodiments of this disclosure relate to positive electrode active materials, methods for preparing positive electrode active materials, positive electrodes including positive electrode active materials, and rechargeable lithium batteries including positive electrodes. Background Technology

[0002] Due to their relatively high energy density and portability, rechargeable lithium batteries have been used as power sources in portable information devices (such as cell phones, laptops, smartphones, etc.) and / or electric vehicles. Recently, research has been actively conducted on using high-energy-density rechargeable lithium batteries as power sources for hybrid vehicles and / or electric vehicles, and / or as energy storage power sources for energy storage systems and / or power walls.

[0003] To develop or realize rechargeable lithium batteries suitable for these applications or purposes, one or more suitable positive electrode active materials are being investigated. Among them, lithium nickel oxides, lithium nickel manganese cobalt composite oxides, lithium nickel cobalt aluminum composite oxides, and lithium cobalt composite oxides are mainly (or dominantly) used as positive electrode active materials.

[0004] However, with the increasing demand for larger size, higher capacity (e.g., charge), higher energy density, and / or improved or increased productivity of rechargeable lithium batteries, there is a need or expectation to develop improved methods for preparing novel positive electrode active materials. Summary of the Invention

[0005] One or more aspects of embodiments of this disclosure relate to a method for efficiently preparing a positive electrode active material comprising core particles in the form of single particles at relatively low heat treatment (e.g., sintering) temperatures without using an alkaline grain growth promoter.

[0006] One or more aspects of embodiments of this disclosure relate to methods that can reduce particle agglomeration (e.g., the degree or occurrence of agglomeration) and make the overall preparation process relatively simple and economical.

[0007] One or more aspects of embodiments of this disclosure relate to positive electrode active materials that are structurally stable and free of residual impurities, thus achieving long cycle life without increasing impedance (e.g., resistance).

[0008] Further aspects of the implementation 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 embodiments of this disclosure.

[0009] In one or more embodiments, the positive electrode active material comprises: a core particle comprising a layered lithium-nickel composite oxide and having (e.g., each having) a single particle shape (e.g., in the form of a single particle); and a coating provided on the surface of the core particle and comprising cobalt and / or zirconium; wherein the lithium-nickel composite oxide of the core particle comprises aluminum and zirconium, based on 100 mol% of total metals other than lithium, a nickel content (e.g., amount) greater than or equal to about 60 mol%, an aluminum content (e.g., amount) of about 0.8 mol% to about 1.5 mol%, and a zirconium content (e.g., amount) of about 0.1 mol% to about 0.3 mol%, and a molar ratio (Al / Zr) of aluminum content (e.g., amount) to zirconium content (e.g., amount) greater than or equal to about 5.

[0010] In one or more embodiments, a method for preparing a positive electrode active material includes: performing a co-precipitation reaction, wherein a mixture of a nickel precursor and a metal precursor is maintained at about pH 11 to about pH 12 for more than or equal to 30 hours to prepare a nickel-based composite hydroxide; mixing the nickel-based composite hydroxide, anhydrous lithium hydroxide, aluminum raw material, and zirconium raw material, and performing a first heat treatment to obtain secondary particles comprising layered lithium-nickel composite oxides and obtained by agglomerating multiple primary particles; pulverizing the secondary particles; and adding the pulverized result, a cobalt coating material, and a zirconium coating material to an aqueous (e.g., water-soluble) solvent and mixing; and then performing a second heat treatment to obtain the positive electrode active material.

[0011] In one or more embodiments, the positive electrode includes a positive electrode current collector; and a positive electrode active material layer provided on the positive electrode current collector and including the positive electrode active material as described in one or more embodiments.

[0012] In one or more embodiments, the rechargeable lithium battery includes: a positive electrode as described in one or more embodiments; a negative electrode; and an electrolyte.

[0013] According to one or more embodiments, positive electrode active materials can be synthesized by a simple method at relatively low heat treatment temperatures. Because no alkaline grain growth promoters are used during the synthesis process, virtually no residue remains, thus the impedance (e.g., resistance) does not increase, and the material is structurally stable, enabling or providing long cycle life characteristics for rechargeable lithium batteries. For example, because no alkaline grain growth promoters are used during the synthesis process, virtually no residue remains, preventing or inhibiting an increase in resistance. This results in a structurally stable material that contributes to achieving long cycle life characteristics for rechargeable lithium batteries. Attached Figure Description

[0014] Figures 1-4Schematic diagrams illustrating rechargeable lithium batteries according to one or more embodiments.

[0015] Figure 5 The results of scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analysis of the composition of the coating on the surface of the positive electrode active material prepared in Example 1 are explained.

[0016] Figure 6 The graphs illustrate the cycle life characteristics of the rechargeable lithium battery cells manufactured in Examples 1, 2 and 1.

[0017] Explanation of reference numerals in the attached figures

[0018] 100: Rechargeable lithium battery; 10: Positive electrode

[0019] 11: Positive electrode lead connector 12: Positive electrode terminal

[0020] 20: Negative electrode 21: Negative electrode lead connector

[0021] 22: Negative electrode terminal; 30: Diaphragm

[0022] 40: Electrode assembly; 50: Housing

[0023] 60: Sealing component; 70: Electrode terminal piece

[0024] 71: Positive electrode connector; 72: Negative electrode connector Detailed Implementation

[0025] Embodiments of this disclosure will be described in more detail below. However, these embodiments are illustrative, and this disclosure is not limited thereto, and is defined by the scope of the claims and their equivalents.

[0026] The singular forms “a,” “an,” and “the” used herein are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, the use of “may” refers to “one or more embodiments of this disclosure” when describing embodiments of the present disclosure.

[0027] In the context of this disclosure, unless otherwise defined, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively.

[0028] As used herein, the term “about” and similar terms are used as approximations and not as terms of degree, and are intended to describe the inherent deviations of measured or calculated values ​​that would be recognized by one of ordinary skill in the art. The terms “about” or “approximately” as used herein also include stated values ​​and refer to an acceptable range of deviation for a particular value as determined by one of ordinary skill in the art, taking into account the measurement under discussion and errors associated with the measurement of a particular quantity (e.g., limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0029] Any numerical range set forth herein is intended to include all subranges with substantially the same numerical precision covered within the set forth range. For example, the range “1.0 to 10.0” is intended to include all subranges between (and inclusive of) the set forth minimum value of 1.0 and the set forth maximum value of 10.0, i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit set forth herein is intended to include all lower numerical limits covered therein, and any minimum numerical limit set forth in this specification is intended to include all higher numerical limits covered therein. Accordingly, the applicant reserves the right to amend this disclosure (including the claims) to expressly set forth any subranges covered within the range expressly set forth herein.

[0030] As used herein, unless otherwise specifically defined, it will be understood that if an element (such as a layer, film, region, or substrate) is referred to as being "on" another element (such as a layer, film, region, or substrate), it may be directly on the other element (such as a layer, film, region, or substrate), or an intermediary element may be present. In contrast, if an element (such as a layer, film, region, or substrate) is referred to as being "directly on" another element (such as a layer, film, region, or substrate), then an intermediary element is not present.

[0031] As used herein, the singular may also include the plural unless otherwise specified. In one or more embodiments, unless otherwise indicated, “A or B” may mean “including A, including B, or including both A and B”.

[0032] As used herein, “combinations thereof” may refer to mixtures, stacks, complexes, copolymers, alloys, blends, reaction products, etc.

[0033] Unless otherwise defined, the particle size used herein may be the average particle size. This average particle size refers to the average particle size (D0). 50The average particle size (D) is the diameter of particles that constitute 50% of the total volume in the particle size distribution. 50 The average particle size (D) can be measured using methods commonly used or available to those skilled in the art, such as by using a particle size analyzer, transmission electron microscope, and / or scanning electron microscope. In one or more embodiments, a dynamic light scattering measurement device can be used for data analysis, and the number of particles can be counted for each particle size range. Based on this data, the average particle size (D) can be readily obtained by calculation. 50 The value can also be obtained using laser diffraction methods. If, for example, the measurement is performed by laser diffraction, the particles to be measured can be dispersed in a dispersion medium, and then an ultrasonic wave of approximately 28 kHz can be introduced into a commonly available or commonly used laser diffraction particle size measurement device (e.g., the MT3000 available from Microtrac, Ltd.). After irradiation with an output power of 60 W, the average particle size (D) based on 50% by volume of the particle size distribution in the measurement device can be calculated. 50 ).

[0034] In this document, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of specific features, quantities, steps (e.g., actions or tasks), elements and / or combinations thereof (e.g., any suitable combination), but do not preclude the possibility of the presence or addition of one or more other features, quantities, steps (e.g., actions or tasks), elements and / or combinations thereof (e.g., any suitable combination).

[0035] The term "metal" is defined as including common metals, transition metals, and / or quasi-metals (semi-metals).

[0036] In the accompanying drawings, the thickness of components (e.g., layers, films, panels, areas, etc.) is magnified to effectively illustrate the technical content. The same reference numerals or symbols refer to the same elements throughout the document, and their repeated description is not required throughout the specification.

[0037] Positive electrode active material

[0038] In one or more embodiments, the positive electrode active material may include: a core particle comprising a layered lithium-nickel composite oxide and having (e.g., each having) a single particle shape (e.g., in the form of a single particle); and a coating provided on the surface of the core particle and comprising cobalt and / or zirconium; wherein the lithium-nickel composite oxide of the core particle may include aluminum and zirconium, and based on 100 mol% of total metals other than lithium, the nickel content (e.g., amount) may be greater than or equal to about 60 mol%, the aluminum content (e.g., amount) may be about 0.8 mol% to about 1.5 mol%, and the zirconium content (e.g., amount) may be about 0.1 mol% to about 0.3 mol%, and the molar ratio (Al / Zr) of the aluminum content (e.g., amount) to the zirconium content (e.g., amount) may be greater than or equal to about 5.

[0039] High-nickel positive electrode active materials with a nickel content (e.g., amount) greater than or equal to about 60 mol% are currently being actively developed because they can achieve relatively high energy densities. However, these high-nickel positive electrode active materials have limitations, such as structural degradation due to charging and discharging, surface side reactions with the electrolyte (e.g., undesirable side reactions), and degradation due to particle cracking. Therefore, it is desirable to develop positive electrode active materials that achieve both high energy density and long cycle life characteristics.

[0040] High-nickel positive electrode active materials (e.g., those with high nickel content) primarily (or dominantly) utilize secondary particle forms formed by agglomerating multiple primary particles to achieve high capacity (e.g., charge). However, recently, the use of single-particle forms to achieve long cycle life and reduce gas generation (e.g., the degree or occurrence of gas generation) has been considered. However, increasing the firing temperature to produce single particles may increase particle agglomeration and potentially reduce productivity.

[0041] To address particle agglomeration and lower firing temperatures, the use of basic grain growth promoters during the synthesis of individual particles has been attempted. However, a problem exists: residual basic grain growth promoters after firing act as or are used as impedance (e.g., resistance) within the positive electrode, leading to a shortened lifetime. In one or more embodiments, if (e.g., when) a rinsing process is performed to remove residual basic grain growth promoters and / or residual salts, preparation costs may increase and the process may become more complex.

[0042] Accordingly, one or more embodiments of this disclosure provide a positive electrode active material that can be effectively synthesized even by heat treatment at relatively low temperatures, which is economical and advantageous for large-scale production, and can achieve or provide excellent or suitable cycle life characteristics due to its relatively high structural stability.

[0043] In order to synthesize even through relatively low-temperature heat treatment and to achieve or provide excellent or appropriate cycle life characteristics, the positive electrode active material may include layered lithium nickel composite oxides as core particles.

[0044] For example, the lithium-nickel composite oxide of the core particles can be a high-nickel oxide (e.g., oxides including those with high nickel content) having the following content (e.g., amount): based on 100 mol% of total metals other than lithium, the nickel content (e.g., amount) is greater than or equal to about 60 mol%. Based on 100 mol% of total metals other than lithium, the nickel content (e.g., amount) of the layered lithium-nickel composite oxide can be, for example, greater than or equal to about 65 mol%, greater than or equal to about 70 mol%, greater than or equal to about 75 mol%, greater than or equal to about 80 mol%, greater than or equal to about 85 mol%, greater than or equal to about 90 mol%, greater than or equal to about 91 mol%, or greater than or equal to about 94 mol% and less than or equal to about 99 mol%, or less than or equal to about 98 mol%.

[0045] In one or more embodiments, in addition to nickel, the lithium-nickel composite oxide of the core particles may include aluminum and zirconium, which act as or are used as a type or type of dopant in a set or specific amount. In the lithium-nickel composite oxide, based on 100 mol% of total metals other than lithium, the aluminum content (e.g., amount) may be from about 0.8 mol% to about 1.5 mol%, for example, from about 0.8 mol% to about 1.4 mol%, from about 0.8 mol% to about 1.3 mol%, or from about 0.9 mol% to about 1.2 mol%. Based on 100 mol% of total metals other than lithium, the zirconium content (e.g., amount) may be from about 0.1 mol% to about 0.3 mol%, for example, from about 0.1 mol% to about 0.2 mol%.

[0046] As an example, the ratio (e.g., molar ratio) of aluminum content (e.g., amount) to zirconium content (e.g., amount) in the lithium-nickel composite oxide of the core particles (Al / Zr) can be greater than or equal to about 5, for example, about 5 to about 20, about 5 to about 15, or about 5 to about 10. In one or more embodiments, the ratio of aluminum content (e.g., amount) to zirconium content (e.g., amount) can be a molar ratio. If (e.g., when) the ratio of aluminum to zirconium content (e.g., amount) meets the foregoing range, synthesis can be carried out at a relatively low firing temperature without the use of, for example, basic grain growth additives during the synthesis process, and the structural stability can be high, thereby achieving or providing long cycle life characteristics.

[0047] In one or more embodiments, the lithium-nickel composite oxide may be represented by chemical formula 1.

[0048] Chemical Formula 1

[0049] Li a1 Ni x1 M 1 y1 Al z1 Zr w1 O 2-b1 X b1

[0050] In chemical formula 1, 0.9 ≤ a1 ≤ 1.2, 0.6 ≤ x1 ≤ 0.991, 0 ≤ y1 ≤ 0.391, 0.008 ≤ z1 ≤ 0.015, 0.001 ≤ w1 ≤ 0.003, 0.9 ≤ x1 + y1 + z1 + w1 ≤ 1.1, and 0 ≤ b1 ≤ 0.1, M 1 X may be one or more elements selected from boron (B), barium (Ba), calcium (Ca), cerium (Ce), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), niobium (Nb), silicon (Si), tin (Sn), strontium (Sr), titanium (Ti), vanadium (V), tungsten (W), yttrium (Y), and zinc (Zn), and X may be one or more elements selected from fluorine (F), phosphorus (P), and sulfur (S).

[0051] In Chemical Formula 1, 0.9 ≤ a1 ≤ 1.1, 0.9 ≤ a1 ≤ 1.05 or 0.9 ≤ a1 ≤ 1. In one or more embodiments, 0.7 ≤ x1 ≤ 0.991 and 0 ≤ y1 ≤ 0.291, or 0.8 ≤ x1 ≤ 0.991 and 0 ≤ y1 ≤ 0.191, or 0.9 ≤ x1 ≤ 0.991 and 0 ≤ y1 ≤ 0.091. The z1 representing the Al content (e.g., amount) can be, for example, 0.008 ≤ z1 ≤ 0.014, 0.008 ≤ z1 ≤ 0.013 or 0.009 ≤ z1 ≤ 0.012. The w1 representing the Zr content (e.g., amount) can be, for example, 0.001 ≤ w1 ≤ 0.002.

[0052] In Chemical Formula 1, 5 ≤ z1 / w1 can be satisfied. For example, 5 ≤ z1 / w1 ≤ 15 or 5 ≤ z1 / w1 ≤ 10.

[0053] For example, the lithium nickel-based composite oxide can be represented by Chemical Formula 2.

[0054] Chemical Formula 2

[0055] Li a2 Ni x2 Co v2 M 2 y2 Al z2 Zr w2 O 2-b2 X b2

[0056] In Chemical Formula 2, 0.9 ≤ a2 ≤ 1.2, 0.6 ≤ x2 < 0.991, 0 < v2 ≤ 0.391, 0 ≤ y2 ≤ 0.391, 0.008 ≤ z2 ≤ 0.015, 0.001 ≤ w2 ≤ 0.003, 0.9 ≤ x2 + v2 + y2 + z2 + w2 ≤ 1.1, and 0 ≤ b2 ≤ 0.1, M 2 can be one or more elements selected from B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zn, and X can be one or more elements selected from F, P, and S.

[0057] In Chemical Formula 2, 5 ≤ z2 / w2 can be satisfied. For example, 5 ≤ z2 / w2 ≤ 15 or 5 ≤ z2 / w2 ≤ 10.

[0058] To ensure or provide structural stability and to achieve or provide long cycle life characteristics of the positive electrode active material, the core particles can be in the form of a single particle. In one or more embodiments, the single particle can exist alone without grain boundaries, can consist of a single type of particle, and can be an independent particle, a monolithic structure, a unified structure, or non-agglomerated or non-agglomerated particles, wherein the particles do not agglomerate or aggregate with each other, but can exist as an independent phase in morphology, and can be represented as a single particle (or a unified particle or a single grain), such as a single crystal. The single particle can exist independently, or the single particles can adhere together. For example, two to nine single particles can adhere together and can be in contact with each other.

[0059] In one or more embodiments, a single particle may exist alone, or five or fewer single particles may adhere to each other.

[0060] As an example, the average particle size (D) of the nuclear particles 50 The average particle size can be approximately 1 μm to approximately 4 μm, for example, approximately 1.5 μm to approximately 4 μm, approximately 2 μm to approximately 4 μm, or approximately 2 μm to approximately 3.8 μm. Single particles satisfying the aforementioned average particle size range can have structural stability, increase the energy density of the positive electrode, and improve or enhance the long cycle life characteristics of rechargeable lithium batteries. In one or more embodiments, for example, the particle size distribution can be obtained by randomly measuring the particle size (e.g., diameter, major diameter, and / or major axis length) of 20 particles in a scanning electron microscope image, and the average particle size (D) is calculated here by accumulating the size of particles representing 50% of the total volume. 50 In the context of this application, unless otherwise defined, “diameter” or “size” indicates particle size or average particle size if (e.g., when) the particles are spherical (e.g., substantially spherical), and “diameter” or “size” indicates major axis length or average major axis length if (e.g., when) the particles are non-spherical.

[0061] In order to ensure or provide excellent or appropriate cycle life characteristics by improving or enhancing the surface stability and ionic conductivity of the positive electrode active material, the positive electrode active material may include a coating.

[0062] The positive electrode active material may include a coating provided on the surface of the core particle and comprising cobalt and / or zirconium. By including cobalt and / or zirconium in the coating, the structural stability of the core particle can be improved or enhanced, and side reactions with the electrolyte (e.g., the extent or occurrence of undesirable side reactions) can be effectively or appropriately suppressed or reduced, thereby improving or enhancing capacity (e.g., capacitance) characteristics and charging and discharging efficiency.

[0063] In one or more embodiments, the coating may be formed or provided continuously (e.g., substantially continuously) on the core, or it may be formed or provided in a discontinuous (e.g., substantially discontinuous) island shape. For example, in the coating, at least one selected from cobalt (Co) and zirconium (Zr) may be present in the form or shape of islands.

[0064] For example, due to diffusion or other effects during the preparation process, the coating may further include nickel, manganese, etc., which flow from the nucleus, in addition to cobalt and / or zirconium. However, the coating may be a layer containing the largest amount of cobalt and / or zirconium and using them as its main (or dominant) components.

[0065] As an example, the coating thickness can be from about 5 nm to about 500 nm, for example, from about 10 nm to about 300 nm or from about 50 nm to about 200 nm. Within the aforementioned range, the coating can achieve or provide the effect of improving or enhancing cycle life characteristics without acting as or being used as an impedance (e.g., resistance) and reducing capacity (e.g., capacitance). In one or more embodiments, the coating thickness can be measured, for example, by SEM, TEM, time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), and / or energy-dispersive X-ray spectroscopy (EDS), and as an example, it can be measured by EDS line profile analysis of the cross-section of the positive electrode active material.

[0066] In one or more embodiments, based on 100 mol% of total metals other than lithium in the positive electrode active material, the cobalt content (e.g., amount) of the coating may be from about 0.5 mol% to about 5 mol%, for example, from about 0.7 mol% to about 4 mol%, from about 0.8 mol% to about 3 mol%, or from about 1 mol% to about 2 mol%. Within the foregoing range, the coating may effectively or suitably improve or enhance cycle life characteristics without acting as or being used as a resistor and without reducing capacity (e.g., capacitance).

[0067] For example, based on 100 mol% of total metals other than lithium in the positive electrode active material, the zirconium content (e.g., amount) of the coating can be from about 0.1 mol% to about 3 mol%, for example, from about 0.2 mol% to about 2 mol% or from about 0.3 mol% to about 1 mol%. Within the foregoing range, the coating can improve or enhance cycle life characteristics without acting as or being used as a resistor, and without reducing capacity (e.g., capacitance).

[0068] In one or more embodiments, the zirconium content (e.g., amount) in the coating is... zr ) and cobalt content (e.g., amount) (W co molar ratio (W) zr / W coThe concentration can be from about 1.1 to about 10, for example, from about 1.5 to about 9, from about 2 to about 8, or from about 5 to about 7. Within the aforementioned range, the effects of adding cobalt and zirconium to the coating can be coordinated or synergistic with each other.

[0069] Methods for preparing positive electrode active materials

[0070] In one or more embodiments, a method for preparing a positive electrode active material may include: (i) performing a co-precipitation reaction, wherein a mixture of a nickel precursor and a metal precursor is maintained at about pH 11 to about pH 12 for more than or equal to 30 hours to prepare a nickel-based composite hydroxide; (ii) mixing the nickel-based composite hydroxide, anhydrous lithium hydroxide, aluminum raw material, and zirconium raw material, and performing a first heat treatment to obtain secondary particles comprising layered lithium-nickel composite oxides and obtained by agglomerating multiple primary particles; (iii) pulverizing the secondary particles; and (iv) adding the pulverized result, cobalt coating material, and zirconium coating material to an aqueous (e.g., water-soluble) solvent and mixing, followed by a second heat treatment to obtain the positive electrode active material.

[0071] The aforementioned preparation method relates to a method for preparing a positive electrode active material as described in one or more embodiments. According to this preparation method, high-nickel positive electrode active materials in the form of single particles can be manufactured at relatively low firing temperatures and in a relatively simple manner without the addition of an alkaline particle growth promoter, thereby improving or increasing productivity and cost-effectiveness.

[0072] In the preparation method according to one or more embodiments, if (e.g., when) a nickel-based composite hydroxide and a lithium raw material (e.g., anhydrous lithium hydroxide) are mixed and heat-treated, aluminum and zirconium raw materials can be added together (e.g., sequentially or simultaneously) and heat-treated (e.g., sintered). It should be understood that the aluminum and zirconium raw materials can act as or be used as dopants, and simultaneously (e.g., simultaneously) as or be used as basic grain growth promoters. If (e.g., when) aluminum and zirconium raw materials are added, this addition can promote or enhance grain growth, making the synthesis of single particles at lower temperatures more efficient or appropriate than commonly used or generally available methods for synthesizing single particles. Therefore, particle agglomeration or aggregation (e.g., the degree or occurrence of agglomeration or aggregation) can be suppressed or reduced, and productivity can be improved or increased. Commonly available or commonly used basic particle growth promoters and / or basic particle growth fluxes may have post-sintering residue problems, which can act as or be used as impedance (e.g., resistance) within the positive electrode, thereby reducing cycle life. However, in one or more embodiments, by using aluminum raw materials and / or zirconium raw materials as dopants for the positive electrode active material, they do not remain on the surface of the positive electrode active material particles, thus improving or enhancing cycle life characteristics.

[0073] The method for preparing the positive electrode active material will be described in more detail below.

[0074] Nickel-based complex hydroxides can serve as precursors for the core particles in the positive electrode active material and can be synthesized via a coprecipitation reaction. In the coprecipitation reaction, the nickel precursor can be a nickel hydroxide, oxide, nitrate, sulfate, carbonate, and / or a combination thereof (e.g., any suitable combination). The metal precursor can be a metal-containing hydroxide, oxide, nitrate, sulfate, carbonate, and / or a combination thereof (e.g., any suitable combination). In one or more embodiments, the metal of the metal precursor can be at least one selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zn.

[0075] In one or more embodiments, in addition to the nickel precursor and the metal precursor, a complexing agent and / or a pH adjuster may be used in the coprecipitation reaction. The complexing agent can be used to control the reaction rate of precipitate formation in the coprecipitation reaction and may include, for example, ammonium hydroxide (NH4OH), citric acid, and / or combinations thereof (e.g., any suitable combination). The concentration of the complexing agent may be from about 0.1 M to about 1.5 M, for example, from about 0.1 M to about 1.4 M or from about 0.5 M to about 1.4 M. The pH adjuster may act as or be used to control the pH of the reactants and may include, for example, sodium hydroxide (NaOH), sodium carbonate (Na2CO3), sodium oxalate (Na2C2O4), and / or combinations thereof (e.g., any suitable combination).

[0076] The coprecipitation reaction can be carried out at about pH 11 to about pH 12 for more than or equal to about 30 hours. If (e.g., when) the foregoing range is met, the nickel-based complex hydroxide obtained by the coprecipitation reaction can have a dense (e.g., substantially dense) form. In one or more embodiments, the coprecipitation reaction can be carried out in a step (e.g., action or task) maintained for more than or equal to about 30 hours within the pH range described in one or more embodiments. For example, the coprecipitation reaction can be carried out at about pH 11.5 to about pH 12, about pH 11.6 to about pH 11.9, or about pH 11.7 to about pH 11.8, and can be carried out for about 30 hours to about 50 hours, about 32 hours to about 45 hours, or about 35 hours to about 40 hours.

[0077] Nickel-based complex hydroxides can be represented, for example, by chemical formula 11.

[0078] Chemical Formula 11

[0079] Ni x11 M1 y11 (OH)2

[0080] In Chemical Formula 11, 0.6 ≤ x11 ≤ 1, 0 ≤ y11 ≤ 0.4, 0.9 ≤ x11 + y11 ≤ 1.1, and M 1 can be one or more elements selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zn.

[0081] In Chemical Formula 11, 0.7 ≤ x11 ≤ 1 and 0 ≤ y11 ≤ 0.3, or 0.8 ≤ x11 ≤ 1 and 0 ≤ y11 ≤ 0.2, or 0.9 ≤ x11 < 1 and 0 < y11 ≤ 0.1.

[0082] The nickel-based composite hydroxide can be represented by Chemical Formula 12 as an example.

[0083] Chemical Formula 12

[0084] Ni x12 Co v12 M 2 y12 (OH)2

[0085] In Chemical Formula 12, 0.6 ≤ x12 < 1, 0 < v12 ≤ 0.4, 0 ≤ y12 ≤ 0.4, and 0.9 ≤ x12 + v12 + y12 ≤ 1.1, and M 2 can be one or more elements selected from B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zn.

[0086] The nickel-based composite hydroxide can be in the form of particles and can have a dense (e.g., substantially dense) structure. If (e.g., when) the foregoing conditions are satisfied, then a core particle in the form of a single particle with excellent or appropriate structural stability can be effectively obtained. For example, the average particle size (D 50 ) of the nickel-based composite hydroxide can be about 10 μm to about 20 μm, e.g., about 10 μm to about 18 μm or about 12 μm to about 16 μm. In one or more embodiments, the average particle size (D 50 ) can be measured by SEM images. The nickel-based composite hydroxide can be large particles, e.g., large particle precursors.

[0087] For example, the nickel-based composite hydroxide can be amorphous (e.g., non-crystalline), which can be confirmed by X-ray diffraction analysis.

[0088] Next, (ii) a nickel-based composite hydroxide, anhydrous lithium hydroxide, aluminum raw material, and zirconium raw material can be mixed and subjected to a first heat treatment. This process can produce secondary particles comprising layered lithium-nickel composite oxides and formed (or provided) by agglomerating multiple primary particles.

[0089] As an example, in process (ii) according to one or more embodiments, based on 1 mole of total metal of nickel-based composite hydroxide, aluminum of aluminum raw material, and zirconium of zirconium raw material, the lithium content (e.g., amount) of anhydrous lithium hydroxide can be about 0.9 moles to about 1.2 moles, for example, about 0.9 moles to about 1.1 moles or about 0.9 moles to about 1.05 moles, for example, greater than about 1 mole and less than about 1.1 moles, for example, about 1.01 moles to about 1.04 moles. By appropriately or suitably controlling the molar ratio of lithium raw materials, core particles with a stable (e.g., substantially stable) structure and good or suitable quality in the form of single particles can be effectively prepared.

[0090] In process (ii) according to one or more embodiments, anhydrous lithium hydroxide can be used as a lithium raw material. By using anhydrous lithium hydroxide as a lithium raw material, the loading capacity can be increased, which helps to improve or increase the hourly output.

[0091] For example, anhydrous lithium hydroxide (LiOH) can be produced by drying the average particle size (D). 50 The hydrated lithium hydroxide (LiOH·H2O) has a particle size of approximately 400 μm to approximately 600 μm and is pulverized to an average particle size of approximately 3 μm to approximately 30 μm (D). 50 The anhydrous lithium hydroxide can be prepared by means of a process called ______. It is not necessary to pulverize the anhydrous lithium hydroxide before drying, but only after drying for about 1 minute. Drying can be carried out, for example, under vacuum conditions at a temperature range of about 50°C to about 200°C for about 0.5 hours to about 20 hours.

[0092] Methods for preparing anhydrous lithium hydroxide allow for the easy acquisition of anhydrous lithium salts, maintaining optimal or appropriate process conditions, and reducing the Li₂CO₃ conversion to approximately 5% or less to obtain high-purity anhydrous lithium hydroxide. After pulverizing anhydrous lithium hydroxide, further processing is often difficult due to the rapid decrease in powder flowability. For example, if drying is performed after pulverization, the fine particles may become entangled and tightly agglomerated due to the heat generated during drying, which may require a re-pulverization process. However, the agglomerated particles may be more difficult to grind due to their relatively high agglomeration strength in the re-pulverization process. In one or more embodiments, as the number of processes increases, the conversion to Li₂CO₃ may also increase due to the increase in specific surface area, thus failing to obtain high-quality anhydrous lithium hydroxide. However, the method for preparing anhydrous lithium hydroxide according to one or more embodiments (where the anhydrous lithium hydroxide is pulverized to a specific size in a single step under set or predetermined conditions after drying) is a relatively simple process for obtaining high-quality anhydrous lithium hydroxide, and further processes can be easily added to it.

[0093] In one or more embodiments, if (e.g., when) anhydrous lithium hydroxide is used instead of hydrated lithium hydroxide as the lithium raw material, the amount of unnecessary or undesirable gases and / or moisture generated during heat treatment can be reduced, thereby improving or enhancing processability and increasing the quality of the positive electrode active material. In one or more embodiments, unnecessary or undesirable heavy materials (such as H2O) can be omitted to increase heat treatment yield and improve or enhance productivity.

[0094] The average particle size (D) of hydrated lithium hydroxide as the starting material 50 The anhydrous lithium hydroxide may be, for example, about 450 μm to about 550 μm or about 480 μm to about 500 μm, but the obtained anhydrous lithium hydroxide may have an average particle size (D) of about 3 μm to about 25 μm or about 5 μm to about 20 μm. 50 In one or more embodiments, the average particle size (D) of the obtained anhydrous lithium hydroxide is... 50 It can be smaller than the average particle size of hydrated lithium hydroxide.

[0095] In one or more embodiments, based on 100 mol% of the total metal of the nickel-based complex hydroxide, the aluminum of the aluminum raw material and the zirconium of the zirconium raw material, the aluminum content (e.g., amount) of the aluminum raw material may be about 0.8 mol% to about 1.5 mol%, for example, about 0.8 mol% to about 1.4 mol%, about 0.8 mol% to about 1.3 mol%, or about 0.9 mol% to about 1.2 mol%.

[0096] For example, based on 100 mol% of total metals in nickel-based complex hydroxides, the aluminum raw material is aluminum and the zirconium raw material is zirconium. The zirconium content (e.g., amount) of the zirconium raw material can be about 0.1 mol% to about 0.3 mol%, for example, about 0.1 mol% to about 0.2 mol%.

[0097] In one or more embodiments, based on the total metal of 100 mol% nickel-based complex hydroxide, the aluminum of the aluminum raw material and the zirconium of the zirconium raw material, the molar ratio (Al / Zr) of the aluminum content (e.g., amount) of the aluminum raw material to the zirconium content (e.g., amount) of the zirconium raw material may be greater than or equal to about 5, for example, about 5 to about 20, about 5 to about 15 or about 5 to about 10.

[0098] It should be understood that the aluminum and zirconium raw materials according to one or more embodiments can serve as raw materials for dopants and, at the same time (e.g., simultaneously), can act as alkaline grain growth promoters, and by adding each of them within the aforementioned content (e.g., amount) range, single particles in the form of nucleated particles in an optimal or appropriate state can be obtained.

[0099] In one or more embodiments, the aluminum raw material may be alumina, such as Al2O3. The zirconium raw material may be zirconium oxide, such as ZrO2.

[0100] The method for preparing positive electrode active materials according to one or more embodiments can ensure heat treatment (e.g., a first heat treatment) at a lower temperature than commonly available or used synthesis methods for single particles. For example, even if the heat treatment is carried out at a relatively low temperature, the process can allow the acquisition of desired, good or suitable single particles as core particles for positive electrode active materials. Accordingly, the process can be simplified, economically improved, particle agglomeration problems reduced, and productivity and processability improved.

[0101] For example, the first heat treatment may be carried out in an oxidizing gas atmosphere, and air and / or oxygen may be used as the oxidizing gas. For example, the first heat treatment may be carried out in an air atmosphere or an atmosphere comprising more than or equal to about 50 vol%, more than or equal to about 60 vol%, more than or equal to about 80 vol%, or more than or equal to about 90 vol%.

[0102] In one or more embodiments, the first heat treatment may be performed at a temperature less than or equal to about 900°C, less than or equal to about 890°C, less than or equal to about 850°C, or less than or equal to about 810°C (e.g., about 700°C to about 900°C, about 710°C to about 890°C, about 730°C to about 850°C, or about 750°C to about 810°C). The first heat treatment may be performed for, for example, about 4 hours to about 20 hours, about 5 hours to about 15 hours, about 6 hours to about 12 hours, or about 8 hours to about 10 hours.

[0103] In the method for preparing the positive electrode active material according to one or more embodiments, during the process of mixing nickel-based composite hydroxide, lithium raw material, aluminum raw material, and zirconium raw material and performing heat treatment, alkaline grain growth promoters and / or alkaline grain growth fluxes may not be added. Accordingly, an increase in impedance (e.g., resistance) due to residues after heat treatment can be prevented or reduced, the cycle life characteristics of the rechargeable lithium battery can be improved or enhanced, and the process and economy can be improved or enhanced without the need for a residue removal process.

[0104] Through a first heat treatment, secondary particles comprising layered lithium-nickel composite oxides and formed by the agglomeration of multiple primary particles can be obtained. At this time, by adding aluminum and zirconium raw materials, the multiple primary particles constituting the secondary particles can be sufficiently or appropriately grown into single crystals, and the secondary particles can have a dense (e.g., substantially dense) structure, thereby effectively obtaining core particles with excellent or appropriate structural stability.

[0105] In one or more embodiments, the secondary particles may be large (e.g., substantially large) particles, and by using precursors of these large particles to carry out the process as described in one or more embodiments, the cake produced during the preparation process may have relatively low hardness, making it relatively easy to crush and improving or increasing hourly productivity.

[0106] For example, the average particle size (D) of secondary particles 50 The size of the secondary particles can be approximately 10 μm to approximately 20 μm, for example, approximately 10 μm to approximately 18 μm or approximately 12 μm to approximately 16 μm. The average particle size (D) of the secondary particles... 50 It can be measured through SEM images.

[0107] The average particle size (D) of the primary particles that constitute (form) secondary particles 50 The particle size can range from approximately 1 μm to approximately 4 μm, for example, approximately 1.5 μm to approximately 4 μm, approximately 2 μm to approximately 4 μm, or approximately 2 μm to approximately 3.5 μm. The average particle size (D) of the primary particles... 50The secondary particles can be measured by SEM images of their surface. The secondary particles may consist of multiple primary particles and pores between the primary particles, and may have a dense (e.g., substantially dense) structure rather than a hollow (e.g., substantially hollow) structure.

[0108] The obtained layered lithium-nickel composite oxide can be represented by chemical formula 1, and chemical formula 1 is described as in one or more embodiments.

[0109] Then, (iii) the obtained secondary particles can be pulverized. In process (iii) as described in one or more embodiments, pulverizing the secondary particles refers to breaking the secondary particles, and may be a process in which multiple primary particles forming the secondary particles are separated from each other to become single particles. By the pulverization process, core particles of the positive electrode active material in the form of single particles can be obtained.

[0110] According to the aforementioned preparation method, if (for example, when) nickel-based composite hydroxide and lithium raw materials are mixed and heat-treated, aluminum raw materials and zirconium raw materials can be added together and heat-treated so that the primary particles can be single particles of sufficient or appropriate size at a relatively low temperature of 900°C or lower. Secondary particles in which these primary particles agglomerate can be obtained, and by pulverizing them, the desired or appropriate single particle form can be obtained as the core particles of the positive electrode active material.

[0111] The grinding can be performed using a jet mill and / or an air classifier (ACM) device. If, for example, a jet mill is used, the air pressure can be appropriately adjusted so that the bulk density of the ground product is about 0.2 g / cm³. 3 ~0.5g / cm 3 And it can be adjusted, for example, to about 2 bar to about 8 bar or about 4 bar to about 6 bar. The pulverization process can be carried out for, for example, about 10 minutes to about 120 minutes (e.g., about 10 minutes to about 80 minutes, about 10 minutes to about 60 minutes or about 20 minutes to about 50 minutes).

[0112] Subsequently, (iv) the pulverized product, the cobalt coating material, and the zirconium coating material may be added to and mixed in an aqueous (e.g., water-soluble) solvent, followed by a second heat treatment to obtain the positive electrode active material. For example, the cobalt coating material may be a hydroxide, oxide, nitrate, sulfate, carbonate, and / or combination thereof (e.g., any suitable combination) comprising cobalt. For example, the zirconium coating material may be a hydroxide, oxide, nitrate, sulfate, carbonate, and / or combination thereof (e.g., any suitable combination) comprising zirconium.

[0113] As an example, an aqueous (e.g., water-soluble) solvent may be a commonly available or commonly used solvent, and may include, for example, water, distilled water, alcohol solvents and / or combinations thereof (e.g., any suitable combination).

[0114] In one or more embodiments, the method may further include adding and mixing the pulverized result, the cobalt coating material, and the zirconium coating material, and then drying it prior to a second heat treatment. For example, the drying prior to the second heat treatment may be performed at about 80°C to about 300°C, about 90°C to about 250°C, about 100°C to about 200°C, about 150°C to about 200°C, or about 180°C to about 200°C.

[0115] For example, the second heat treatment can be carried out in an oxidizing gas atmosphere, and air or oxygen can be used as the oxidizing gas. For example, the second heat treatment can be carried out in an air atmosphere or an atmosphere containing more than or equal to about 50% by volume of oxygen.

[0116] In one or more embodiments, a first oxidizing gas atmosphere may be used for a first heat treatment and a second oxidizing gas atmosphere may be used for a second heat treatment. The first and second oxidizing gas atmospheres may be substantially the same. The first and second oxidizing gas atmospheres may be substantially different. The first and second oxidizing gas atmospheres may each be suitably adjusted or modified.

[0117] In one or more embodiments, the second heat treatment may be performed at about 500°C to about 900°C, about 600°C to about 800°C, or about 650°C to about 750°C. The second heat treatment may be performed in an oxidizing gas atmosphere, for example, for about 8 hours to about 20 hours, about 10 hours to about 20 hours, about 10 hours to about 18 hours, or about 12 hours to about 16 hours. If (for example, when) the foregoing conditions are met, a positive electrode active material having better or more suitable surface stability and improved or enhanced cycle life characteristics can be effectively prepared.

[0118] This process can yield positive electrode active materials.

[0119] In a method for preparing a positive electrode active material according to one or more embodiments, based on 100 mol% of the total metals other than lithium in the finally obtained positive electrode active material, the cobalt content (e.g., amount) of the cobalt coating material can be adjusted to about 0.5 mol% to about 5 mol%, for example, about 0.7 mol% to about 4 mol%, about 0.8 mol% to about 3 mol%, or about 1 mol% to about 2 mol%. Within the foregoing range, the coating can effectively achieve or perform the function of improving or increasing cycle life characteristics without acting as or being used as a resistor, and without reducing capacity (e.g., capacitance).

[0120] In a method for preparing a positive electrode active material according to one or more embodiments, based on 100 mol% of the total metals other than lithium in the finally obtained positive electrode active material, the zirconium content (e.g., amount) of the zirconium coating material can be adjusted to about 0.1 mol% to about 3 mol%, for example, about 0.2 mol% to about 2 mol% or about 0.3 mol% to about 1 mol%. Within the foregoing range, the coating can improve or enhance cycle life characteristics without acting as or being used as a resistor, and without reducing capacity (e.g., capacitance).

[0121] Rechargeable lithium batteries

[0122] In one or more embodiments, the rechargeable lithium battery may include a positive electrode; a negative electrode; and an electrolyte, wherein the positive electrode may include: a positive electrode current collector; and a positive electrode active material layer provided on the positive electrode current collector and comprising the positive electrode active material prepared by the preparation method as described in one or more embodiments.

[0123] In one example, a rechargeable lithium battery may include a positive electrode, a negative electrode, a separator between the positive and negative electrodes, and an electrolyte.

[0124] Rechargeable lithium batteries can be classified according to their shape as cylindrical batteries, prismatic batteries, pouch batteries, coin-shaped batteries, etc. Figures 1-4 Schematic diagrams illustrating rechargeable lithium batteries according to one or more embodiments, wherein... Figure 1 It is a cylindrical battery. Figure 2 It is a prismatic battery, and Figure 3 and Figure 4 It is a pouch battery. (Reference) Figures 1-4 The rechargeable lithium battery 100 may include: an electrode assembly 40 having a separator 30 between a positive electrode 10 and a negative electrode 20; and a housing 50 therein housing the electrode assembly 40. The positive electrode 10, negative electrode 20, and separator 30 may be impregnated with an electrolyte. The rechargeable lithium battery 100 may include a sealing member 60 for sealing the housing 50, such as... Figure 1 Explained in Chinese. Figure 2 In this context, the rechargeable lithium battery 100 may include a positive electrode lead connector 11, a positive electrode terminal 12, a negative electrode lead connector 21, and a negative electrode terminal 22. For example... Figure 3 and Figure 4 The text explains that the rechargeable lithium battery 100 may include electrode terminals 70, such as positive electrode terminal 71 and negative electrode terminal 72, which serve as electrical paths for directing current from the electrode assembly 40 to the outside.

[0125] positive electrode

[0126] The positive electrode may include a positive electrode current collector and a layer of positive electrode active material on the positive electrode current collector. The layer of positive electrode active material may include a positive electrode active material and may optionally further include a binder, a conductive (e.g., electrically conductive) material and / or a combination thereof (e.g., any suitable combination).

[0127] Positive electrode active material

[0128] The positive electrode active material may be a compound capable of reversibly inserting and deintercalating lithium (lithiation intercalation compound), and the positive electrode active material may be as described in one or more embodiments related to the method of preparing the positive electrode active material.

[0129] adhesive

[0130] The binder can improve or enhance the adhesion properties between the positive electrode active material particles and the adhesion properties between the positive electrode active material particles and the positive electrode current collector. Examples of binders may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylate resin, polyester resin and / or nylon, but embodiments of this disclosure are not limited thereto.

[0131] conductive materials

[0132] Conductive materials (e.g., electronic conductors) may be included to provide electrode conductivity, and any suitable conductive material may be used as a conductive material unless it causes a chemical change (e.g., an undesirable chemical change). Examples of conductive (e.g., electrically conductive) materials may include: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, carbon nanotubes, etc.; metallic materials including metal powders and / or metal fibers of copper, nickel, aluminum, silver, etc.; conductive (e.g., electrically conductive) polymers, such as polyphenylene derivatives; and / or mixtures thereof (e.g., any suitable).

[0133] Based on a 100wt% positive electrode active material layer, the content (e.g., amount) of each of the binder and conductive (e.g., electrical conductivity) material may be from about 0.5wt% to about 5wt%.

[0134] The positive electrode current collector may include aluminum (Al) foil, but embodiments of this disclosure are not limited thereto.

[0135] negative electrode

[0136] The negative electrode may include a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector, wherein the negative electrode active material layer may include a negative electrode active material and may further include a binder, a conductive (e.g., electrically conductive) material and / or a combination thereof (e.g., any suitable combination).

[0137] Based on a 100 wt% negative electrode active material layer, the amount of negative electrode active material can be from about 95 wt% to about 99.5 wt%, and based on the 100 wt% negative electrode active material layer, the content (e.g., amount) of binder can be from about 0.5 wt% to about 5 wt%. For example, the negative electrode active material layer may include about 90 wt% to about 99 wt% negative electrode active material, about 0.5 wt% to about 5 wt% binder, and about 0.5 wt% to about 5 wt% conductive (e.g., electrically conductive) material.

[0138] 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 alloys 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.

[0139] Negative electrode active material

[0140] The negative electrode active material may include materials that can reversibly insert / deintercalate lithium ions, lithium metal, lithium metal alloys, materials that can be doped / dedoped with lithium, and / or transition metal oxides.

[0141] Materials capable of reversibly inserting / deintercalating lithium ions may include, for example, crystalline carbon, amorphous (e.g., non-crystalline) carbon, and / or combinations thereof (e.g., any suitable combination) as carbon-based negative electrode active materials. Crystalline carbon may be amorphous (e.g., irregular), and / or sheet-like (e.g., substantially sheet-like), flake-like (e.g., substantially flake-like), spherical (e.g., substantially spherical), or fibrous (e.g., in fibrous form) natural graphite and / or artificial graphite. Amorphous (e.g., non-crystalline) carbon may include soft carbon, hard carbon, mesophase pitch carbonization products, calcined coke, etc.

[0142] Lithium metal alloys may include alloys of lithium and metals selected from sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), silicon (Si), antimony (Sb), lead (Pb), indium (In), zinc (Zn), barium (Ba), radium (Ra), germanium (Ge), aluminum (Al), and tin (Sn).

[0143] The material capable of doping / de-doping lithium can be a Si-based negative electrode active material and / or a Sn-based negative electrode active material. The Si-based negative electrode active material can include silicon, silicon-carbon composite, SiO x (0 < x ≤ 2), Si-Q alloy (where Q can be an element selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements (except Si), Group 15 elements, Group 16 elements, transition metals, rare earth elements, and / or their combinations (e.g., any suitable combination), such as, Mg, Ca, Sr, Ba, Ra, scandium (Sc), yttrium (Y), Ti, Zr, hafnium (Hf), rutherfordium (Rf), vanadium (V), Nb, tantalum (Ta), dubnium (Db), chromium (Cr), Mo, W, seaborgium (Sg), technetium (Tc), rhenium (Re), bohrium (Bh), iron (Fe), lead (Pb), ruthenium (Ru), osmium (Os), hassium (Hs), rhodium (Rh), iridium (Ir), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), B, Al, gallium (Ga), Sn, In, thallium (Tl), Ge, P, arsenic (As), Sb, bismuth (Bi), S, selenium (Se), tellurium (Te), polonium (Po), and / or their combinations (e.g., any suitable combination)) and / or their combinations (e.g., any suitable combination). The Sn-based negative electrode active material can be Sn, SnO k (0 < k ≤ 2) (e.g., SnO2), Sn alloy, and / or their combinations (e.g., any suitable combination).

[0144] The silicon-carbon composite can be a composite of silicon and amorphous (e.g., non-crystalline) carbon. The average particle size (D 50 ) of the silicon-carbon composite particles can be, for example, 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 (e.g., non-crystalline) carbon coated on the surface of the silicon particles. For example, it can include secondary particles (cores) in which silicon primary particles are aggregated and an amorphous (e.g., non-crystalline) carbon coating (shell) on the surface of the secondary particles. Amorphous (e.g., non-crystalline) carbon can also be present between the silicon primary particles. For example, the silicon primary particles can be coated with amorphous (e.g., non-crystalline) carbon. The secondary particles can be dispersed in the amorphous (e.g., non-crystalline) carbon matrix.

[0145] The silicon-carbon composite can further include crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles and an amorphous (e.g., non-crystalline) carbon coating on the surface of the core. The crystalline carbon can be artificial graphite, natural graphite, and / or their combinations (e.g., any suitable combination). The amorphous (e.g., non-crystalline) carbon can include soft carbon, hard carbon, mesophase pitch carbonized products, calcined coke, etc.

[0146] If (e.g., when) the silicon-carbon composite includes silicon and amorphous (e.g., non-crystalline) carbon, then based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of silicon can be about 10 wt% to about 50 wt% and the content (e.g., amount) of amorphous (e.g., non-crystalline) carbon can be about 50 wt% to about 90 wt%. In one or more embodiments, if (e.g., when) the silicon-carbon composite includes silicon, amorphous (e.g., non-crystalline) carbon, and crystalline carbon, then based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of silicon can be about 10 wt% to about 50 wt%, the content (e.g., amount) of crystalline carbon can be about 10 wt% to about 70 wt%, and the content (e.g., amount) of amorphous (e.g., non-crystalline) carbon can be about 20 wt% to about 40 wt%.

[0147] In one or more embodiments, the thickness of the amorphous (e.g., non-crystalline) carbon coating can be about 5 nm to about 100 nm. The average particle size (D 50 ) of the silicon particles (primary particles) can be about 10 nm to about 1 μm or about 10 nm to about 200 nm. The silicon particles can exist alone in the form of silicon, in the form of a silicon alloy, and / or in the oxidized form of silicon. The oxidized form of silicon can be represented by SiO x (0 < x ≤ 2). In one or more embodiments, the atomic content (e.g., amount) ratio of Si:O, which can indicate the degree of oxidation, can be about 99:1 to about 33:67. If (e.g., when) no other definition is provided, then as used herein, 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%.

[0148] Si-based negative electrode active material or Sn-based negative electrode active material can be mixed with carbon-based negative electrode active material. If (e.g., when) Si-based negative electrode active material or Sn-based negative electrode active material is mixed and used with carbon-based negative electrode active material, then the mixing ratio by weight can be about 1:99 to about 90:10.

[0149] Binder

[0150] The binder can serve to or be used for the good or proper adhesion of the negative electrode active material particles to each other, and also serve to or be used for the adhesion of the negative electrode active material to the negative electrode current collector. The binder can be a non-aqueous (e.g., water-insoluble) binder, an aqueous (e.g., water-soluble) binder, a dry (e.g., substantially dry) binder, and / or a combination thereof (e.g., any suitable combination).

[0151] Non-aqueous (e.g., water-insoluble) adhesives may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide and / or combinations thereof (e.g., any suitable combination).

[0152] Waterborne (e.g., water-soluble) adhesives may include styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepoxychloropropane, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and / or combinations thereof (e.g., any suitable combination).

[0153] If, for example, an aqueous (e.g., water-soluble) binder is used as a binder in the negative electrode active material layer, it may further include a cellulose compound capable of imparting or increasing viscosity. As a cellulose compound, one or more selected from carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and their alkali metal salts may be mixed and used. The alkali metal may be sodium (Na), potassium (K), and / or lithium (Li).

[0154] Dry adhesives may be polymeric materials that can be fibrous (e.g., processed into fibers) and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide and / or combinations thereof (e.g., any suitable combination).

[0155] electrolyte

[0156] For example, the electrolyte for a rechargeable lithium battery may be an electrolyte that may include a non-aqueous (e.g., water-insoluble) organic solvent and a lithium salt.

[0157] Non-aqueous (e.g., water-insoluble) organic solvents can act as or be used as a medium for transporting ions that participate in the electrochemical reactions of rechargeable lithium batteries. Non-aqueous (e.g., water-insoluble) organic solvents may include carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents and / or combinations thereof (e.g., any suitable combination).

[0158] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butyl carbonate (BC), etc. Ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolactone, mevalonolactone, valproic acid lactone, 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 may be a C2-C20 straight chain, branched chain or cyclic hydrocarbon group, and may include double bond, aromatic ring, ether bond, etc.); amides, such as dimethylformamide; dioxolane, such as 1,3-dioxolane, 1,4-dioxolane, etc.; sulfolane, etc.

[0159] Non-aqueous (e.g., water-insoluble) organic solvents may be used alone or in mixtures of two or more types or kinds, and if (e.g., when) two or more types or kinds are used in a mixture, the mixing ratio may be appropriately or suitably adjusted according to the desired or appropriate battery performance, which is commonly used or generally available to those skilled in the art.

[0160] If (for example, when) a carbonate solvent is used, cyclic carbonates and chain (e.g., non-cyclic) carbonates can be mixed and used, and cyclic carbonates and chain (e.g., non-cyclic) carbonates can be mixed in a volume ratio of about 1:1 to about 1:9.

[0161] Non-aqueous (e.g., water-insoluble) organic solvents may further include aromatic hydrocarbon organic solvents. For example, carbonate solvents and aromatic hydrocarbon organic solvents may be mixed and used in a volume ratio of about 1:1 to about 30:1.

[0162] The electrolyte may further include vinyl ethyl carbonate, vinylene carbonate and / or ethylene carbonate compounds to improve or enhance the cycle life of rechargeable lithium batteries.

[0163] Examples of ethylene carbonate compounds may include fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, and / or cyanoethylene carbonate.

[0164] Lithium salts dissolved in non-aqueous (e.g., water-insoluble) organic solvents can supply lithium ions in rechargeable lithium batteries, ensuring basic operation and improving or enhancing lithium ion transport between the positive and negative electrodes. Examples of lithium salts may include those selected from LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide; LiFSI), LiC4F9SO3, LiN(C x F 2x+ 1SO2)(C y F 2y+1 SO2 (where x and y can be integers from 1 to 20), lithium trifluoromethane sulfonate, lithium tetrafluoroethane sulfonate, lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0165] The concentration of lithium salt can be in the range of about 0.1 M to about 2.0 M. If (for example, when) the concentration of lithium salt is within the aforementioned range, the electrolyte can have suitable or appropriate ionic conductivity and viscosity, thus achieving excellent or appropriate performance, and lithium ions can move effectively or appropriately.

[0166] diaphragm

[0167] Depending on the type or variety of rechargeable lithium-ion battery, the separator may be located between the positive and negative electrodes. The separator may include polyethylene separators, polypropylene separators, polyvinylidene fluoride separators, and / or multilayer films of two or more layers (such as polyethylene / polypropylene two-layer separators, polyethylene / polypropylene / polypropylene three-layer separators, polypropylene / polypropylene / polypropylene three-layer separators, etc.).

[0168] The diaphragm may include a porous substrate and a coating on the surface of the porous substrate (e.g., one surface or two surfaces (e.g., two opposite (or oppositely oriented) surfaces)), the coating comprising organic materials, inorganic materials and / or combinations thereof (e.g., any suitable combination).

[0169] The porous substrate may be a polymer film selected from any one of the following polymers and / or copolymers or (e.g., any suitable) of them: polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fiber, polytetrafluoroethylene (e.g., Teflon). TM ).

[0170] The porous substrate may have a thickness of about 1 μm to about 40 μm (e.g., 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).

[0171] Organic materials may include (meth)acrylic acid copolymers, which include: a first structural unit derived from (meth)acrylamide; and a second structural unit including at least one structural unit selected from structural units derived from (meth)acrylic acid or (meth)acrylates and structural units derived from (meth)acrylamidosulfonic acid or salts thereof.

[0172] Inorganic materials may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and / or combinations thereof (e.g., any suitable combination), but embodiments of this disclosure are not limited thereto. The average particle size (D) of the inorganic particles... 50 The range can be approximately 1 nm to approximately 2000 nm, for example, approximately 100 nm to approximately 1000 nm or approximately 100 nm to approximately 700 nm.

[0173] Organic and inorganic materials can be mixed in a coating, or they can exist in the form of a coating that includes organic materials and a coating that includes inorganic materials stacked together.

[0174] The thickness of the coating can be from about 0.5 μm to about 20 μm, for example, from about 1 μm to about 10 μm or from about 1 μm to about 5 μm.

[0175] The embodiments and comparative examples of this disclosure are described in more detail below. However, the following examples are merely illustrative of this disclosure, and the implementation of this disclosure is not limited to the following examples.

[0176] Example 1

[0177] 1. Preparation of positive electrode active material

[0178] (1) Preparation of nickel-based complex hydroxides

[0179] Nickel-based complex hydroxides were prepared via a co-precipitation method as described below. A mixed solution of the metal raw materials was prepared by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in distilled water as a solvent, such that the molar ratio of Ni:Co:Mn was 95:4:1. A dilute ammonia solution (NH4OH) was prepared as a complexing agent, and sodium hydroxide (NaOH) was prepared as a pH adjuster. The concentration of the ammonia solution was 10 wt%, and the concentration of the sodium hydroxide was 20 wt%. The prepared mixed solution of the metal raw materials, the ammonia solution, and the sodium hydroxide were then separately injected into a reactor.

[0180] Nickel-based complex hydroxides were synthesized by stirring in a reactor at pH 11.75 for 37 hours.

[0181] The slurry solution in the filter reactor is rinsed with high-purity distilled water and dried in a hot air oven at 180°C for 24 hours to obtain nickel-based composite hydroxide (Ni 0.95 Co 0.04 Mn 0.01 (OH)2). The obtained nickel-based composite hydroxides were in the form of secondary particles formed by the agglomeration of multiple primary particles, wherein the secondary particles had an average particle size of approximately 15 μm when measured by SEM images (D). 50 ).

[0182] (2) Preparation of positive electrode active material

[0183] The obtained nickel-based composite hydroxide was mixed with anhydrous lithium hydroxide, Al₂O₃, and ZrO₂. Anhydrous lithium hydroxide was mixed such that the molar ratio of lithium to the total metal of the nickel-based composite hydroxide was 1.05. Furthermore, Al₂O₃ was added such that, based on 100 mol% of the total metal of the nickel-based composite hydroxide, the Al content of Al₂O₃ and the Zr content of ZrO₂ were 1 mol%, and ZrO₂ was added such that, based on 100 mol% of the total metal of the nickel-based composite hydroxide, the Al content of Al₂O₃ and the Zr content of ZrO₂ were 0.1 mol%.

[0184] The mixture was heat-treated at 810°C for 8 hours under an atmosphere containing 90% by volume oxygen. The product obtained from the first heat treatment exhibited Li 1.00 Ni 0.939 Co 0.04 Mn 0.01 Al 0.01 Zr 0.001 The composition of O2 was determined, and upon observation via SEM images, it was confirmed to exist in the form of secondary particles. The average particle size (D) of the secondary particles was measured via SEM images. 50 The average particle size (D) of the primary particles that form secondary particles is approximately 15 μm. 50It is approximately 3μm.

[0185] The product obtained from the first heat treatment was pulverized for 20 minutes using a jet mill under an air pressure of about 5 bar. When examined by SEM images, it was confirmed that the pulverized product consisted of single particles with an average particle size of about 3 μm.

[0186] The pulverized material was washed with distilled water solvent and coated with cobalt and zirconium by adding Co(OH)₂ and ZrO₂ and mixing them. Subsequently, the distilled water solvent was removed, and the material was dried at 190°C. Then, a second heat treatment was performed at 710°C for 12 hours in an atmosphere containing 50 vol% oxygen to obtain a positive electrode active material with a core of single particles containing Co and Zr and a coating 50 nm thick on the single particle core. At this point, based on the total metals excluding lithium in 100 wt% of the final positive electrode active material, the cobalt content (e.g., amount) of the coating was designed to be 2 mol%, and based on the total metals excluding lithium in 100 wt% of the final positive electrode active material, the Zr content (e.g., amount) of the coating was designed to be 0.3 mol%.

[0187] In summary, in Example 1, a co-precipitation method was used to prepare nickel-based composite hydroxides. A mixed solution of nickel sulfate, cobalt sulfate, and manganese sulfate was dissolved in distilled water, with ammonia and sodium hydroxide used as a complexing agent and a pH adjuster, respectively. The mixture was stirred at pH 11.75 for 37 hours, then filtered, washed, and dried to obtain nickel-based composite hydroxides in the form of secondary particles with an average particle size of about 15 μm.

[0188] The nickel-based complex hydroxide was then mixed with anhydrous lithium hydroxide, Al₂O₃, and ZrO₂, and subjected to a first heat treatment at 810°C for 8 hours in an oxygen-rich atmosphere. The resulting product (containing Li₂O₃) was then subjected to a first heat treatment at 810°C for 8 hours. 1.00 Ni 0.939 Co 0.04 Mn 0.01 Al 0.01 Zr 0.001 The O2 composition was pulverized to form single particles with an average particle size of about 3 μm. These particles were rinsed, coated with Co(OH)2 and ZrO2, dried, and subjected to a second heat treatment at 710 °C to obtain a positive electrode active material with a single particle core and a 50 nm thick Co and Zr coating.

[0189] 2. Manufacturing of rechargeable lithium battery cells

[0190] A positive electrode active material layer slurry is prepared by mixing 98.5 wt% of the manufactured positive electrode active material, 1.0 wt% of polyvinylidene fluoride binder, and 0.5 wt% of carbon nanotube conductive (e.g., electrically conductive) material, and the positive electrode active material layer slurry is coated onto an aluminum foil current collector to manufacture a positive electrode. The manufactured positive electrode contains positive electrode active material in the form of single particles obtained by pulverization.

[0191] An electrode assembly is manufactured using a positive electrode, a lithium counter electrode as a negative electrode, and a polytetrafluoroethylene separator between them. After inserting the electrode assembly into a rechargeable lithium battery casing, an electrolyte (prepared by mixing ethylene carbonate and dimethyl carbonate in a volume ratio of 3:7 and dissolving 1M LiPF6 in the mixed solvent) is injected into it to manufacture a rechargeable lithium battery half-cell cell using conventional methods.

[0192] Example 2

[0193] The positive electrode active material and rechargeable lithium battery cell were manufactured in essentially the same manner as in Example 1, except that ZrO2 was mixed in such that, based on 100 mol% of the total metals other than lithium in the final positive electrode active material, Zr was 0.2 mol%.

[0194] Comparative Example 1

[0195] The positive electrode active material and rechargeable lithium battery cell were manufactured in essentially the same manner as in Example 1, except that the positive electrode active material was prepared without mixing ZrO2 throughout the entire preparation process. In Comparative Example 1, the secondary particles were not pulverized by jet milling because the primary particles forming the secondary particles did not crystallize to a sufficient size during the first heat treatment at 810°C. On the other hand, in Examples 1 and 2, when Al2O3 and ZrO2, each with a predetermined or set amount (e.g., quantity), were added during the first heat treatment at essentially the same temperature conditions to perform Al and Zr doping, grain growth of the nuclei, i.e., growth of the primary particles or crystallization of the primary particles, was promoted.

[0196] Comparative Example 2

[0197] The positive electrode active material and rechargeable lithium battery cell were manufactured in essentially the same manner as in Example 1, except that the positive electrode active material was prepared by mixing ZrO2, such that Zr became 0.3 mol% based on 100 mol% of the total metals other than lithium in the final positive electrode active material. The Al / Zr ratio of Comparative Example 2 was 3.33, which is less than 5.

[0198] Comparative Example 3

[0199] The positive electrode active material and rechargeable lithium battery cells were manufactured in essentially the same manner as in Example 1, except that the pH conditions were increased to 12.3 when producing the nickel-based composite hydroxide to obtain an average particle size (D). 50 Nickel-based composite hydroxides in the form of secondary particles of approximately 3 μm were obtained, and as the result of the first heat treatment, an average particle size (D) was obtained. 50 Secondary particles of approximately 3 μm are used as small particles.

[0200] Comparative Example 4

[0201] The positive electrode active material and rechargeable lithium battery cell were manufactured in essentially the same manner as in Example 1, except that no cobalt coating was performed when producing the positive electrode active material because Co(OH)2 was not mixed in.

[0202] Evaluation Example 1: Evaluation of Coating Components

[0203] To evaluate the composition of the coating of the positive electrode active material prepared in Example 1, SEM-EDS analysis was performed, and the results are as follows: Figure 5 As explained in the paper. Here, SEM-EDS was analyzed using a Philips FEI Titan 80-300 at an accelerating voltage of 15kV.

[0204] refer to Figure 5 The coating provided on the surface of the positive electrode active material manufactured in Example 1 contains cobalt (Co) and zirconium (Zr).

[0205] Evaluation Example 2: Evaluation of Cycle Life Characteristics

[0206] The rechargeable lithium-ion battery cells according to Examples 1 and 2 and Comparative Example 1 were charged at 25°C with a constant current of 0.2C to 4.45V, then charged at a constant voltage of 0.05C to 3.0V, and then discharged at 0.2C to 3.0V for initial charge and discharge. Subsequently, at 45°C, the battery cells were repeatedly charged and discharged at 1.0C 61 times within a voltage range of 3.0V to 4.45V. The ratio of the discharge capacity to the initial discharge capacity in each cycle was... Figure 6 The Chinese explanation is "capacity retention rate (%)".

[0207] refer to Figure 6 In Comparative Example 1, the capacity retention decreased with cycling because single crystallization was not performed in the core particles of the positive electrode active material. In contrast, Examples 1 and 2 demonstrate excellent or adequate cycle life characteristics.

[0208] Evaluation Example 3: Load Assessment

[0209] The loading of positive electrode active materials prepared according to Example 1 and Comparative Example 3 was tested, and the test results are illustrated in Table 1.

[0210] Table 1

[0211]

[0212]

[0213] Referring to the results in Table 1, when the positive electrode active material prepared according to Comparative Example 3 was loaded, large agglomeration of single particles was observed by using a small particle precursor, separation of the top and bottom was observed, and large agglomeration occurred, resulting in different XRD physical properties of the top and bottom.

[0214] In contrast, when the positive electrode active material prepared according to Example 1 is loaded, by using a large particle precursor during the preparation process, there is no separation between the top and bottom and less agglomeration, making it possible to obtain a substantially uniform positive electrode active material layer with very small differences in XRD physical properties between the top and bottom.

[0215] Evaluation Example 4: Evaluation of Charging and Discharging Efficiency

[0216] After the initial charging and discharging as in Evaluation Example 2, the rechargeable lithium battery cells of Example 1 and Comparative Examples 2 to 4 were subsequently charged and discharged 60 times at 1.0C in a voltage range of 3.0V to 4.45V at 45°C to measure the charging capacity and discharging capacity. The ratio of the latter to the former was then calculated as “charge and discharge efficiency (%)”, and the results are illustrated in Table 2.

[0217] Table 2

[0218] Charging capacity (mAh / g) Discharge capacity (mAh / g) Charging and discharging efficiency (%) Example 1 235.8 204.5 86.7 Comparative Example 2 235.0 202.0 85.9 Comparative Example 3 235.1 201.6 85.8 Comparative Example 4 235.6 202.2 85.8

[0219] Referring to Table 2, the positive electrode active material prepared by employing the large-particle precursor according to Example 1 exhibits excellent charge and discharge capacity as well as excellent charge and discharge efficiency.

[0220] In contrast, when the positive electrode active material prepared according to Comparative Example 2 was used, the initial charge / discharge capacity, efficiency, and cycle life characteristics decreased, presumably due to the overgrowth of primary particles during the core particle formation process. Furthermore, the positive electrode active material prepared using the small particle precursor according to Comparative Example 3 exhibited insufficient charge and discharge efficiency, as well as slightly lower charge and discharge capacity. Moreover, when the positive electrode active material prepared according to Comparative Example 4 was used, the charge capacity, discharge capacity, and charge and discharge efficiency were somewhat low because the coating did not contain cobalt.

[0221] In the context of this application, unless otherwise defined:

[0222] Single-particle form: A single particle refers to an independent particle that exists alone without aggregation or agglomeration. This form has a monolithic structure, indicating that it is a single, monolithic structure without grain boundaries. A single particle can be a single crystal or comprise several crystals, and it can exist as an independent phase, wherein the particles do not aggregate or agglomerate with each other. In one or more embodiments, the single particle may include unagglomerated or non-agglomerated primary particles. The average particle size of the single particle can range from about 1000 nm to about 4000 nm (corresponding to about 1 μm to about 4 μm, respectively).

[0223] Secondary particle form: Secondary particles refer to particles formed by the aggregation or agglomeration of multiple primary particles. This form has a polycrystalline structure, indicating that it is composed of multiple primary particles aggregated or agglomerated together. Secondary particles can have spherical (e.g., substantially spherical) or ellipsoidal (e.g., substantially ellipsoidal) shapes and can include coatings to improve structural stability and conductivity. The average particle size of secondary particles can range from about 10 μm to about 20 μm, while the average particle size of primary particles is from about 1 μm to about 4 μm.

[0224] In one or more embodiments, a single particle form refers to an independent, non-aggregated or non-clustered particle, which may include primary particles (e.g., may be primary particles) and may have an irregular (e.g., amorphous) shape, while a secondary particle form may involve multiple primary particles aggregated or clustered together.

[0225] The battery manufacturing apparatus, battery management system (BMS) apparatus, and / or any other related apparatus or component according to one or more embodiments of this disclosure may be implemented using any suitable hardware, firmware (e.g., application-specific integrated circuits), software, and / or combinations of software, firmware, and hardware (e.g., any suitable combination). For example, one or more suitable components of the apparatus may be provided on an integrated circuit (IC) chip or a standalone IC chip. Further, one or more suitable components of the apparatus may be implemented on a flexible printed circuit film, a tape-on package (TCP), or a printed circuit board (PCB), and / or provided on a substrate. Further, one or more suitable components of the apparatus may be a process or thread that runs on one or more processors in one or more computing devices, executes computer program instructions, and interacts with other system components to perform one or more suitable functions described herein. The computer program instructions may be stored in memory, which may be implemented in the computing device using standard memory devices (such as random access memory (RAM), for example). The computer program instructions may also be stored in other non-transitory computer-readable media (such as CD-ROMs, flash drives, etc., for example). Furthermore, those skilled in the art will recognize that, without departing from the scope of this disclosure, the functions of one or more suitable computing devices may be combined or integrated into a single computing device, or the functions of a particular computing device may be distributed across one or more other computing devices.

[0226] In view of the overall content of this disclosure, those skilled in the art will recognize that each suitable feature of one or more embodiments of this disclosure may be combined in part or in whole, or combined with each other, and may be technically linked and operated in one or more suitable ways, unless otherwise stated or implied, each embodiment may be implemented independently of each other or in combination with each other in any suitable way.

[0227] Although the subject matter of this disclosure has been described in conjunction with embodiments currently considered practical, it will be understood that this disclosure should not be limited to the disclosed embodiments. Instead, it is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the claims and their equivalents. Therefore, it will be understood that the foregoing one or more embodiments are merely illustrative and not restrictive in all respects.

Claims

1. A positive electrode active material, comprising: Core particles, including layered lithium-nickel composite oxides, are in the form of single particles; and A coating is provided on the surface of the core particles and contains cobalt and zirconium; The lithium-nickel composite oxide of the core particle comprises aluminum and zirconium, based on 100 mol% of total metals excluding lithium, with a nickel content greater than or equal to 60 mol%, an aluminum content of 0.8 mol% to 1.5 mol%, and a zirconium content of 0.1 mol% to 0.3 mol%, and a molar ratio of aluminum to zirconium (Al / Zr) greater than or equal to 5.

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

3. The positive electrode active material as described in claim 1, wherein: The average particle size of the nuclear particles is 1 μm to 4 μm.

4. The positive electrode active material as described in claim 1, wherein: The thickness of the coating is 5nm to 500nm.

5. The positive electrode active material as described in claim 1, wherein: In the lithium-nickel composite oxide, the nickel content is 80 mol% to 99 mol% based on 100 mol% of total metals excluding lithium.

6. The positive electrode active material as described in claim 1, wherein: In the positive electrode active material, based on 100 mol% of total metals excluding lithium, the cobalt content of the coating is 0.5 mol% to 5 mol%.

7. The positive electrode active material as described in claim 1, wherein: In the positive electrode active material, based on 100 mol% of total metals excluding lithium, the zirconium content of the coating is 0.1 mol% to 3 mol%.

8. A method for preparing a positive electrode active material, comprising: A coprecipitation reaction was carried out, in which a mixture of nickel precursor and metal precursor was maintained at pH 11–12 for more than or equal to 30 hours to prepare nickel-based complex hydroxides. The nickel-based composite hydroxide, anhydrous lithium hydroxide, aluminum raw material, and zirconium raw material are mixed and subjected to a first heat treatment to obtain secondary particles comprising layered lithium-nickel composite oxides and obtained by agglomerating multiple primary particles. Crushing the secondary particles, and The pulverized product, cobalt coating material, and zirconium coating material are added to an aqueous solvent and mixed, followed by a second heat treatment to obtain the positive electrode active material.

9. The method of claim 8, wherein: The metal precursor is one or more elements selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zn.

10. The method of claim 8, wherein: Based on 100 mol% of the total metals of the nickel-based composite hydroxide, the aluminum of the aluminum raw material and the zirconium of the zirconium raw material, wherein the aluminum content of the aluminum raw material is 0.8 mol% to 1.5 mol% and the zirconium content of the zirconium raw material is 0.1 mol% to 0.3 mol%, and the molar ratio of the aluminum content to the zirconium content Al / Zr is greater than or equal to 5.

11. The method of claim 8, wherein: The nickel-based composite hydroxide has an average particle size of 10 μm to 20 μm and is amorphous.

12. The method of claim 8, wherein: The aluminum raw material is alumina, and The zirconium raw material is zirconium oxide.

13. The method of claim 8, wherein: Based on 100 mol% of total metals other than lithium in the final obtained positive electrode active material, the cobalt content of the cobalt coating material is adjusted to 0.5 mol% to 5 mol%, and the zirconium content of the zirconium coating material is adjusted to 0.1 mol% to 3 mol%.

14. The method of claim 8, wherein: The first heat treatment is carried out in a first oxidizing gas atmosphere at 700℃~900℃ for 4 hours~20 hours, and The second heat treatment is carried out in a second oxidizing gas atmosphere at 500°C to 900°C for 8 to 20 hours.

15. The method of claim 8, wherein: The nickel-based complex hydroxide is represented by chemical formula 11: Chemical Formula 11 Ni x11 M 1 y11 (OH)2, and In chemical formula 11, 0.6 ≤ x11 ≤ 1, 0 ≤ y11 ≤ 0.4, 0.9 ≤ x11 + y11 ≤ 1.1, and M 1 It is one or more elements selected from B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zn.

16. The method of claim 8, wherein: The average particle size of the secondary particles is 10 μm to 20 μm, and The average particle size of the plurality of primary particles constituting the secondary particles is 1 μm to 4 μm.

17. A positive electrode, comprising: Positive electrode current collector; and A positive electrode active material layer is provided on the positive electrode current collector and includes the positive electrode active material as claimed in any one of claims 1 to 7 or the positive electrode active material prepared by any one of claims 8 to 16.

18. A rechargeable lithium battery, comprising: The positive electrode as described in claim 17; negative electrode; and Electrolyte.

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