Positive electrode active material, and positive electrode and lithium secondary battery comprising same

Abstract

The invention relates to a positive electrode active material, a positive electrode containing the positive electrode active material, and a lithium secondary battery. The positive electrode active material includes a lithium nickel-based composite oxide including nickel (Ni), cobalt (Co), and aluminum (Al), and includes a first region and a second region around (e.g., surrounding) the first region. The second region may be defined as a region having a thickness of about 1 [mu] m ([mu] m) in a direction from an outermost surface to a center of the positive electrode active material. The nickel to aluminum content (e.g., amount) ratio (NNi / NAl) of the second zone may be from about 5 to about 45.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0027444, filed on February 26, 2024, and Korean Patent Application No. 10-2024-0134603, filed on October 4, 2024, in the Korean Intellectual Property Office, the entire contents of each of which are incorporated herein by reference. Technical Field

[0003] According to one or more embodiments, the present disclosure relates to a positive electrode active material, and a positive electrode and a lithium secondary battery including the same. Background Art

[0004] Recently, the rapid spread and popularity of battery-powered and / or battery-using electronic devices (such as mobile phones, laptop computers, etc.) and / or electric vehicles has driven the desire or demand for secondary batteries equipped with or provided with relatively high energy density and high capacity. Accordingly, research and development are being actively conducted to improve the performance of lithium secondary batteries (for example, as a driving power source for hybrid and / or electric vehicles and / or as a power source for energy storage systems (ESS)).

[0005] A lithium secondary battery is a battery comprising a positive electrode and a negative electrode, each of which comprises an active material capable of (configured for) the intercalation and deintercalation of lithium ions and an electrolyte. If (for example, when) lithium ions are intercalated into and deintercalated from the positive and negative electrodes during the charge and discharge processes, the lithium secondary battery generates electrical energy through oxidation and reduction reactions. Summary of the Invention

[0006] One or more aspects relate to a positive electrode active material having high capacity, excellent or appropriate (e.g., high) capacity retention, and low resistance change even after repeated charge and discharge, as well as a positive electrode and a lithium secondary battery including the positive electrode active material. Additional aspects will be set forth in part in the subsequent description and in part will be apparent from the description, or may be understood by practicing the presented embodiments of the present disclosure.

[0007] The positive electrode active material according to one or more embodiments of the present disclosure includes a lithium nickel-based composite oxide containing (e.g., comprising) nickel (Ni), cobalt (Co), and aluminum (Al), and includes a first region and a second region, the second region being located around (e.g., surrounding) the first region and defined as a region having a thickness of about 1 micrometer (μm) in a direction from the outermost surface of the positive electrode active material to the center of the positive electrode active material, wherein the content (e.g., amount) ratio (N) of nickel to aluminum in the second region is 1:1. Ni / N Al) can be from about 5 to about 45.

[0008] The positive electrode according to one or more embodiments of the present disclosure includes a positive electrode current collector and a positive electrode active material layer, wherein the positive electrode active material layer may include a positive electrode active material.

[0009] A lithium secondary battery according to one or more embodiments of the present disclosure may include a positive electrode active material. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated into and constitute a part of this specification. The drawings illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. In the drawings:

[0011] Figure 1 A conceptual diagram schematically illustrating a lithium secondary battery according to one or more embodiments of the present disclosure.

[0012] Figures 2 to 5 are schematic diagrams each schematically illustrating a lithium secondary battery according to one or more embodiments of the present disclosure.

[0013] Figure 6 is a schematic diagram of a positive electrode according to one or more embodiments of the present disclosure.

[0014] Figure 7 and Figure 9 Schematic diagrams each illustrating a positive electrode active material according to one or more embodiments of the present disclosure.

[0015] Figure 8 for Figure 7 Magnified view of area M in FIG.

[0016] Figure 10 A flow chart illustrating a method for preparing a positive electrode active material according to one or more embodiments of the present disclosure.

[0017] Figure 11 1 is a flow chart illustrating step (eg, action or task) S100 of a method for preparing a positive electrode active material according to one or more embodiments of the present disclosure.

[0018] Figure 12 Schematic diagrams illustrating steps S300 and S500 of a method for preparing a positive electrode active material according to one or more embodiments of the present disclosure.

[0019] Figure 13 Schematic diagram illustrating step (eg, action or task) S700 of a method for preparing a positive electrode active material according to one or more embodiments of the present disclosure.

[0020] Figure 14 and Figure 15 Schematic diagrams each illustrating a step (eg, action or task) S900 of a method for preparing a positive electrode active material according to one or more embodiments of the present disclosure.

[0021] Figure 16 The results of mapping the cross section of the positive electrode active material according to Example 1 using a transmission electron microscope (TEM) image and energy dispersive spectroscopy (EDS) are explained.

[0022] Figures 17A to 17C The depth analysis results of the cross section of the positive electrode active material according to Example 1 were obtained using a transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS). DETAILED DESCRIPTION

[0023] In order to fully understand the layout and effects of the present disclosure, one or more embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be noted that the present disclosure is not limited to one or more embodiments and can be implemented in one or more suitable forms. On the contrary, one or more embodiments are provided only to fully and clearly describe the present disclosure in more detail, to the extent that those skilled in the art can fully understand the scope of the present disclosure and easily implement the present disclosure.

[0024] In the description, if (for example, when) an element is referred to as being "on" another element, the element may be formed directly on the other element, or an intervening element may be present therebetween. In contrast, if (for example, when) an element is referred to as being "directly on" another element, no intervening element is present. In the drawings, the thickness of some components is exaggerated for efficient explanation of the technical content. The same reference numerals refer to the same elements throughout the specification, and their repeated description may not be provided in the specification.

[0025] Expressions in the singular (e.g., “a,” “an,” and “the”) may include expressions in the plural (including “at least one”) unless the context clearly indicates otherwise. In addition, the phrase “A or B” may indicate “A but not B,” “B but not A,” and “A and B,” unless specifically stated otherwise. The terms “comprises / includes,” “comprising / including,” “comprise,” “include,” “having,” “has,” and / or “have” as used in this description are intended to indicate the presence of specified aspects, features, quantities, steps (e.g., actions or tasks), elements, components, and / or their (e.g., any appropriate) combination, and do not preclude the presence or addition of one or more other aspects, features, quantities, steps (e.g., actions or tasks), elements, components, and / or their (e.g., any appropriate) combination. Additionally, the terms “comprise(s) / comprising,” “include(s) / including,” “have / has / having,” or other similar terms encompass or support the terms “consisting of” and “consisting essentially of,” and “consisting of” and “consisting essentially of” indicate the presence of recited features, integers, steps, operations, elements, and / or components while the absence or substantial absence of other features, integers, steps, operations, elements, components, and / or groups thereof.

[0026] As used herein, the term "combination thereof" may refer to a mixture, stack, composite, copolymer, alloy, blend, or reaction product of the components.

[0027] In one or more embodiments, the term “layer” herein includes not only a shape formed on the entire surface but also a shape formed on a partial surface if (for example, when) viewed from a plan view.

[0028] It will be understood that although the terms "first," "second," "third," etc. may be used herein to describe one or more appropriate elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Thus, a first element, component, region, layer, or portion described herein may be referred to as a second element, component, region, layer, or portion without departing from the teachings set forth herein.

[0029] As utilized herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of," "one of," and "selected from" if (e.g., when) preceding / following a list of elements modify the entire list of elements and do not modify the individual elements of the list. For example, the expressions "at least one of a through c" and "at least one of a, b, and c" may refer to only a, only b, only c, both a and b (e.g., simultaneously), both a and c (e.g., simultaneously), b and c (e.g., simultaneously), all of a, b, and c, or variations thereof.

[0030] Spatially relative terms such as "below," "beneath," "below," "above," "on," etc. may be used herein to easily describe the relationship between one element or feature and another element or feature. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation illustrated in the drawings. For example, if (e.g., when) the device in the drawings is turned over, an element described as being "below" or "beneath" other elements or features will be oriented "above" the other elements or features. Thus, the example term "below" can (e.g., simultaneously) encompass both orientations of above and below. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative terms used herein can be interpreted accordingly.

[0031] The terms used herein are only used to describe the purpose of specific embodiments and are not intended to limit the present disclosure. Unless defined otherwise, all terms used in the present disclosure (including chemical terms, technical terms and scientific terms) have the same meaning as those generally understood by those of ordinary skill in the art to which the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having the same meaning as that in the context of the relevant art and the present disclosure, and will not be interpreted in an ideal or overly formal sense.

[0032] Example embodiments are described herein with reference to cross-sectional views that are schematic representations of idealized embodiments. As such, variations in the illustrated shapes can be expected, for example, as a result of manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the regions illustrated herein, but are intended to include deviations in shape that result, for example, from manufacturing. For example, a region illustrated or described as flat may typically have rough and / or nonlinear features. Moreover, illustrated sharp corners may be rounded. Therefore, the regions illustrated in the drawings are schematic in nature, and their shapes are not intended to illustrate the precise shape of the regions and are not intended to limit the scope of the claims presented.

[0033] The term "may" will be understood to refer to "one or more embodiments of the present disclosure," some of which include the element being described and some of which exclude the element and / or include alternative elements. Similarly, alternative language such as "or" refers to "one or more embodiments of the present disclosure" that each include the corresponding enumerated item.

[0034] In this context, "consisting essentially of" means that any additional components do not significantly affect the chemical, physical, optical or electrical properties of the target moiety.

[0035] Further, in this specification, the phrase “on a plane” or “plan view” indicates that a target portion is viewed from the top, and the phrase “on a cross section” indicates that a cross section formed by vertically cutting the target portion is viewed from the side.

[0036] As used herein, the terms "particle diameter," "particle size," and the like refer to the average particle diameter of the particles if (e.g., when) the particles are spherical, and refer to the average major axis length of the particles if (e.g., when) the particles are non-spherical. For example, the particle diameter may be the average particle diameter, and the particle diameter refers to the average particle diameter (D 50 ), which refers to the diameter of particles with a cumulative volume of 50% by volume in the particle size distribution. Average particle size (D 50 ) can be measured by methods well known to those skilled in the art, for example, by a particle size analyzer, or by using a transmission electron microscope (TEM) image or a scanning electron microscope (SEM) image. In one or more embodiments, the average particle size can be measured by a measuring device using dynamic light scattering, wherein data analysis is performed to count particles in each particle size range, and then the average particle size (D) can be obtained by calculation. 50 ) value. Also, a laser scattering method can be used to measure the average particle size. In the laser scattering method, target particles are dispersed in a dispersion medium and then introduced into a commercial laser diffraction particle size measuring instrument (e.g., MT 3000 from Microtrac), and ultrasonic waves of about 28 kHz are irradiated at an output of 60 W, and the average particle size (D) based on about 50% of the particle size distribution can be calculated in the measuring instrument. 50 ).

[0037] In the description, a single particle may refer to a single particle existing alone without grain boundaries. In terms of morphology, a single particle may refer to a particle existing as an independent phase in which the particles are not aggregated together, a monolithic structure, a single integrated structure, or a non-aggregated particle. For example, a single particle may be a single crystal. Alternatively, a single particle may be a particle containing several crystals. Single particles may be individually separated. Alternatively, a single particle may be in a form having about 2 to about 100 single particles bonded together.

[0038] Figure 1is a simplified conceptual diagram of a lithium secondary battery according to one or more embodiments of the present disclosure. Figure 1 The lithium secondary battery may include a positive electrode 10, a negative electrode 20, a separator 30 and an electrolyte ELL.

[0039] The positive electrode 10 and the negative electrode 20 may be separated and / or isolated from each other (e.g., spaced apart or separated) by a separator 30. The separator 30 may be disposed between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20, and the separator 30 may be in contact with the electrolyte ELL. The positive electrode 10, the negative electrode 20, and the separator 30 may be immersed in the electrolyte ELL.

[0040] The electrolyte ELL may be a medium for transferring lithium ions between the positive electrode 10 and the negative electrode 20. In the electrolyte ELL, the lithium ions may move toward the positive electrode 10 or the negative electrode 20 through the separator 30.

[0041] Positive electrode 10

[0042] The positive electrode 10 for a lithium secondary battery may include a positive electrode current collector COL1 and a positive electrode active material layer AML1 on the positive electrode current collector COL1. The positive electrode active material layer AML1 may include a positive electrode active material and may further include a binder and / or a conductive material (eg, an electron conductor).

[0043] For example, the positive electrode 10 may further include a component that may serve as a sacrificial positive electrode.

[0044] The amount of the positive electrode active material may be about 90 wt % to about 99 wt % based on 100 wt % of the positive electrode active material layer AML1. The amount of the binder and the conductive material may be about 0.5 wt % to about 5 wt % based on 100 wt % of the positive electrode active material layer AML1.

[0045] The binder is used to adhere the positive electrode active material particles to each other and also to adhere the positive electrode active material to the positive electrode current collector COL1. Examples of the binder may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc. as non-limiting examples.

[0046] Conductive materials can be used to impart electrical conductivity (e.g., electrical conductivity) to the electrodes. Any material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in lithium secondary batteries) and conducts electrons can be used in the battery. Examples of conductive materials may include: carbon materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal materials including copper, nickel, aluminum, silver, etc. in the form of metal powders or metal fibers; conductive polymers (such as polyphenylene derivatives); and / or (e.g., any suitable) mixtures thereof.

[0047] An Al foil may be used as the positive electrode current collector COL1 , but the present disclosure is not limited thereto.

[0048] Positive electrode active material

[0049] The positive electrode active material may include a compound capable of intercalating and deintercalating lithium (lithiated intercalation compound). For example, at least one composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and / or one or more thereof (e.g., any appropriate combination) may be used as the positive electrode active material.

[0050] The composite oxide may be a lithium transition metal composite oxide. Specific examples of the composite oxide may include lithium nickel oxides (i.e., lithium nickel composite oxides), lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free nickel manganese oxides, and / or any suitable combination thereof.

[0051] As an example, the following compounds represented by any one of the following chemical formulas can be used as the positive electrode active material. a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, and 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8 and 0.001≤b≤0.1);Li a CoG b O2(0.90≤a≤1.8 and 0.001≤b≤0.1);Li a Mn 1-b G b O2(0.90≤a≤1.8 and 0.001≤b≤0.1);Li a Mn2G b O4 (0.90≤a≤1.8 and 0.001≤b≤0.1); Li a Mn 1-g G g PO4 (0.90≤a≤1.8 and 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); or Li a FePO4(0.90≤a≤1.8).

[0052] In the aforementioned chemical formula, A may be Ni, Co, Mn, and / or any suitable combination thereof; X may be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, and / or any suitable combination thereof; D may be O, F, S, P, and / or any suitable combination thereof; G may be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and / or any suitable combination thereof; and L 1 It can be Mn, Al, and / or (eg, any suitable) combination thereof.

[0053] The positive electrode active material may be, for example, a high nickel-based positive electrode active material having a nickel content (e.g., amount) 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% of a metal other than lithium based on 100 mol% of a lithium transition metal composite oxide (i.e., a high nickel-based positive electrode active material). The high nickel-based positive electrode active material may be capable of achieving high capacity and may be applied to high-capacity, high-density lithium secondary batteries.

[0054] Negative electrode 20

[0055] The negative electrode 20 for a lithium secondary battery may include a negative electrode current collector COL2 and a negative electrode active material layer AML2 on the negative electrode current collector COL2. The negative electrode active material layer AML2 may include a negative electrode active material and may further include a binder and / or a conductive material (e.g., an electron conductor).

[0056] For example, the negative electrode active material layer AML2 may include about 90 wt % to about 99.5 wt % of a negative electrode active material, about 0.5 wt % to about 5 wt % of a binder, and about 0 wt % to about 5 wt % of a conductive material, based on the total weight (100 wt %) of the negative electrode active material layer AML2.

[0057] The binder can be used to make the negative electrode active material particles adhere well to each other and also to make the negative electrode active material adhere well to the negative electrode current collector COL 2. The binder can include a non-aqueous binder, an aqueous binder, a dry binder, and / or any suitable combination thereof.

[0058] The non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, and / or (eg, any suitable) combinations thereof.

[0059] The aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol and / or (e.g., any appropriate) combination thereof.

[0060] If (for example, when) an aqueous binder is used as a binder in the negative electrode active material layer AML2, a cellulose compound capable of imparting viscosity may be further included. The cellulose compound may include at least one of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and an alkali metal salt thereof. The alkali metal may include Na, K, or Li.

[0061] The dry binder may be a polymer material capable of being fiberized. For example, the dry binder may be polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and / or any suitable combination thereof.

[0062] Conductive materials can be used to impart conductivity to electrodes. Any material that does not cause chemical changes and is an electronic conductive material can be used in the battery. Examples of conductive materials can include: carbonaceous materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metallic materials in the form of metal powder or metal fiber including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; and / or their (e.g., any suitable) mixtures.

[0063] The negative electrode current collector COL2 can use copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and / or their (e.g., any suitable) combination.

[0064] Negative electrode active material

[0065] The negative electrode active material in the negative electrode active material layer AML2 can include materials that can reversibly intercalate and deintercalate lithium ions, lithium metal, lithium metal alloys, materials capable of doping / dedoping lithium, and / or transition metal oxides.

[0066] Materials that can reversibly intercalate and deintercalate lithium ions can include carbonaceous negative electrode active materials, e.g., crystalline carbon, amorphous carbon, and / or their (e.g., any suitable) combination. The crystalline carbon can be graphite, such as amorphous, flaky, lamellar, spherical, or fibrous natural graphite and / or artificial graphite. The amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbonized product, calcined coke, etc.

[0067] The lithium metal alloy can include an alloy of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0068] Materials capable of doping / dedoping lithium can be Si-based negative electrode active materials or Sn-based negative electrode active materials. The Si-based negative electrode active materials can include silicon, silicon-carbon composites, SiO x (0 < x ≤ 2, e.g., SiO2), Si-Q alloys (where Q is 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 (e.g., any suitable) combination), and / or their (e.g., any suitable) combination. The Sn-based negative electrode active materials can include Sn, SnO x (where 0 < x ≤ 2, e.g., SnO2), Sn-based alloys, and / or their (e.g., any suitable) combination.

[0069] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one or more embodiments, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite may include secondary particles (cores) in which primary silicon particles are aggregated and an amorphous carbon coating (shell) on the surface of the secondary particles. Amorphous carbon may also be between primary silicon particles, and, for example, primary silicon particles may be coated with amorphous carbon. Secondary particles may be dispersed in an amorphous carbon matrix.

[0070] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core including crystalline carbon and silicon particles and an amorphous carbon coating on the surface of the core.

[0071] A Si-based negative electrode active material or a Sn-based negative electrode active material may be used in combination with a carbon-based negative electrode active material.

[0072] Diaphragm 30

[0073] Depending on the type (kind) of the lithium secondary battery, the separator 30 may be present between the positive electrode 10 and the negative electrode 20. The separator 30 may include a polyethylene separator, a polypropylene separator, a polyvinylidene fluoride separator, or a multilayer of two or more layers thereof, such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, a polypropylene / polyethylene / polypropylene three-layer separator, and the like.

[0074] The separator 30 may include a porous substrate and a coating on one or both surfaces (eg, opposite surfaces) of the porous substrate, the coating including an organic material, an inorganic material, and / or (eg, any suitable) combination thereof.

[0075] The porous substrate may be a polymer film formed from any one polymer selected from the group consisting of polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyetherketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, and polytetrafluoroethylene (e.g., Teflon), or copolymers or mixtures of two or more thereof.

[0076] The organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0077] The inorganic material 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 inorganic particles thereof (e.g., any suitable) combination thereof, but the present disclosure is not limited thereto.

[0078] An organic material and an inorganic material may be mixed in one coating layer, or a coating layer including an organic material and a coating layer including an inorganic material may be stacked.

[0079] Electrolyte ELL

[0080] The electrolyte ELL for a lithium secondary battery may include a non-aqueous organic solvent and a lithium salt.

[0081] The non-aqueous organic solvent may serve as a medium for transporting ions participating in the electrochemical reaction of the battery.

[0082] The non-aqueous organic solvent may include a carbonate-based solvent, an ester-based solvent, an ether-based solvent, a ketone-based solvent, an alcohol-based solvent, an aprotic solvent, and / or (eg, any appropriate) combinations thereof.

[0083] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), ethylmethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc.

[0084] The ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonolactone, valerolactone, caprolactone, and the like.

[0085] Ether solvents may include dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. In some embodiments, ketone solvents may include cyclohexanone, etc. Alcohol solvents may include ethanol, isopropanol, etc., and aprotic solvents may include nitriles, such as R-CN (wherein R is a C2 to C20 linear, branched, or cyclic hydrocarbon group, and may include a double bond, an aromatic ring, or an ether bond); amides, such as dimethylformamide; dioxolanes, such as 1,3-dioxolane, 1,4-dioxolane, etc.; sulfolane, etc.

[0086] The nonaqueous organic solvents may be used alone or in combination of two or more.

[0087] In some embodiments, if (for example, when) a carbonate-based solvent is used, cyclic carbonate and chain carbonate may be mixed and used, and the cyclic carbonate and chain carbonate may be mixed in a volume ratio of about 1:1 to about 1:9.

[0088] The lithium salt dissolved in the non-aqueous organic solvent provides lithium ions in the battery, ensures the basic operation of the lithium secondary battery, and improves the transport of lithium ions between the positive electrode and the negative electrode. Examples of lithium salts 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+1 SO2)(C y F 2y+1 SO2) (wherein x and y are integers of 1 to 20), at least one of lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBOP) and lithium bis(oxalato)borate (LiBOB).

[0089] lithium secondary batteries

[0090] Lithium secondary batteries may be classified according to their shapes into cylindrical batteries, prismatic batteries, pouch-type (like) batteries, coin-type (like) batteries, and the like. Figures 2 to 5 A schematic diagram illustrating a lithium secondary battery according to one or more embodiments. Figure 2 A cylindrical battery is shown, Figure 3 A prismatic cell is shown, and Figure 4 and Figure 5 Shows a pouch type battery. Figures 2 to 5 , the lithium secondary battery 100 may include: an electrode assembly 40 including a separator 30 between a positive electrode 10 and a negative electrode 20, and a case 50 in which the electrode assembly 40 is housed. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte. Figure 2 As shown, the lithium secondary battery 100 may include a sealing member 60 that seals the housing 50. Figure 3 In the embodiment, the lithium secondary battery 100 may include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. Figure 4 and Figure 5 As shown, the lithium secondary battery 100 may include electrode tabs 70 , which may be, for example, a positive electrode tab 71 and a negative electrode tab 72 , serving as an electrical path for guiding current formed in the electrode assembly 40 to the outside.

[0091] The lithium secondary battery according to one or more embodiments may be applied to, as non-limiting examples, vehicles, mobile phones, and / or one or more other electronic devices of appropriate types (kinds).

[0092] Figure 6Schematic diagram of a positive electrode according to one or more embodiments disclosed in the present invention. Figures 1 to 5 The configurations described are the same as those described above, and the differences will be described in more detail.

[0093] The positive electrode 10 may include a positive electrode current collector COL1 and a positive electrode active material layer AML1 formed on the positive electrode current collector COL1. The positive electrode active material layer AML1 may include a positive electrode active material CAM (hereinafter, simply referred to as "CAM") to be described later, and may further include a binder and / or a conductive material.

[0094] The contents (eg, amounts) of the positive electrode active material CAM, the binder, the conductive material, and the positive electrode current collector COL1 are as described above. The description of the positive electrode active material CAM is as described herein.

[0095] Positive electrode active material CAM

[0096] Figures 7 to 9 A schematic diagram for explaining (eg, illustrating) a positive electrode active material according to one or more embodiments of the present disclosure. Figure 8 for Figure 7 Magnified view of area M in FIG.

[0097] refer to Figure 7 The positive electrode active material CAM may be in a polycrystalline form and may include secondary particles in which at least two primary particles PRP (hereinafter, may be simply referred to as “PRP”) are aggregated, for example, the secondary particles may be aggregates of primary particles.

[0098] The positive electrode active material CAM may be spherical or ellipsoidal.

[0099] The average particle size d of the positive electrode active material CAM may be in the range of about 5 micrometers (μm) to about 25 μm. For example, the average particle size d of the positive electrode active material CAM may be in the range of about 7 μm to about 25 μm, about 10 μm to about 25 μm, or about 10 μm to about 20 μm. For example, the average particle size d of the positive electrode active material CAM may be obtained by randomly selecting about 30 particles of the positive electrode active material CAM in the form of secondary particles from an electron microscope image of the positive electrode active material CAM, measuring the particle sizes, and taking the diameter of the particles representing about 50% by volume of the cumulative volume in the particle size distribution as the average particle size.

[0100] The positive electrode active material CAM may include a core COR (hereinafter, may be simply referred to as “COR”) and a coating layer CTL (hereinafter, may be simply referred to as “CTL”).

[0101] The core COR may be in a polycrystalline form and may include secondary particles in which at least two primary particles PRP are aggregated.

[0102] The core COR may include a lithium nickel composite oxide. The lithium nickel composite oxide may include lithium (Li) and a transition metal. The transition metal may include nickel (Ni). The content (eg, amount) of nickel (Ni) contained in the lithium nickel composite oxide is not limited.

[0103] In other words, the positive electrode active material CAM may be in a polycrystalline form and include secondary particles formed by the aggregation of at least two primary particles PRP. The CAM may be spherical or ellipsoidal, with an average particle size d in the range of about 5 micrometers (μm) to about 25 μm. For example, the average particle size may be about 7 μm to about 25 μm, about 10 μm to about 25 μm, or about 10 μm to about 20 μm. The average particle size can be determined by selecting about 30 CAM secondary particles from an electron microscope image, measuring their diameters, and using the diameter of the particles that account for about 50% by volume of the cumulative volume in the particle size distribution as the average particle size.

[0104] The CAM may include a core (COR) and a coating (CTL). The core, in a polycrystalline form, is composed of secondary particles in which (e.g., in each secondary particle) primary particles are aggregated. The core may comprise a lithium nickel composite oxide comprising lithium (Li) and a transition metal such as nickel (Ni). The amount of nickel in the lithium nickel composite oxide is not limited.

[0105] For example, the lithium nickel composite oxide may be a lithium nickel composite oxide including a high content (e.g., amount) of nickel (Ni). For example, the lithium nickel composite oxide may be a lithium nickel composite oxide in which the content (e.g., amount) of nickel (Ni) based on 100 mol% of metals other than lithium in the lithium nickel composite oxide is about 60 mol% or more, about 80 mol% or more, about 90 mol% or more, or about 95 mol% or more and about 100 mol% or less, about 99.9 mol% or less, or about 99 mol% or less. For example, the lithium nickel composite oxide may be a lithium nickel composite oxide in which the molar ratio of nickel (Ni) relative to the total moles of transition metals in the lithium nickel composite oxide is about 60 mol% or more, about 80 mol% or more, about 90 mol% or more, or about 95 mol% or more and about 100 mol% or less, about 99.9 mol% or less, or about 99 mol% or less. If (eg, when) the content (eg, amount) of nickel (Ni) satisfies the range described herein, the positive electrode active material CAM may achieve high capacity and high performance.

[0106] In one or more embodiments, the lithium nickel-based composite oxide may be represented by Chemical Formula 1.

[0107] Chemical formula 1

[0108] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0109] In Chemical Formula 1, 0.9≤a1≤1.8, 0.6≤x1≤1, 0≤y1≤0.2, 0≤z1≤0.2, 0.9≤x1+y1+z1≤1.1, 0≤b1≤0.1, M 1 and M 2 Each of the above elements may be independently selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sr, Ti, V, W, Y, and Zr, and X may be selected from the group consisting of F, P, and S.

[0110] For example, in Chemical Formula 1, 0.85≤x1≤1, 0≤y1≤0.15, and 0≤z1≤0.15 may be satisfied, or 0.9≤x1≤1, 0≤y1≤0.1, and 0≤z1≤0.1 may be satisfied.

[0111] For example, x1+y1+z1=1.

[0112] For example, the lithium nickel-based composite oxide may be represented by Chemical Formula 2. The compound represented by Chemical Formula 2 may be a lithium nickel cobalt-based composite oxide.

[0113] Chemical formula 2

[0114] Li a2 Ni x2 Co y2 M 3 z2 O 2-b2 X b2

[0115] In chemical formula 2, 0.9≤a2≤1.8, 0.6≤x2<1, 0 <y2≤0.2,0≤z2≤0.2,0.9≤x2+y2+z2≤1.1,0≤b2≤0.1,M 3 It may be one or more (e.g., at least one) element selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sr, Ti, V, W, Y, and Zr, and X may be one or more (e.g., at least one) element selected from the group consisting of F, P, and S.

[0116] For example, in Chemical Formula 2, 0.85≤x2≤0.99, 0.01≤y2≤0.15, and 0.01≤z2≤0.15 may be satisfied, or 0.9≤x2≤0.99, 0.01≤y2≤0.1, and 0.01≤z2≤0.1 may be satisfied.

[0117] For example, x2+y2+z2=1.

[0118] For example, the lithium nickel-based composite oxide may be represented by Chemical Formula 3. The compound represented by Chemical Formula 3 may be lithium nickel cobalt aluminum oxide or lithium nickel cobalt manganese oxide.

[0119] Chemical formula 3

[0120] Li a3 Ni x3 Co y3 M 4 z3 M 5 w3 O 2-b3 X b3

[0121] In Chemical Formula 3, 0.9≤a3≤1.8, 0.6≤x3≤0.98, 0.01≤y3≤0.19, 0.01≤z3≤0.19, 0≤w3≤0.19, 0.9≤x3+y3+z3+w3≤1.1, 0≤b3≤0.1, M 4 It may be one or more (eg, at least one) element selected from the group consisting of Al and Mn, wherein M 5 It may be one or more (e.g., at least one) elements selected from the group consisting of B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mo, Nb, Si, Sr, Ti, V, W, Y, and Zr, and X may be one or more (e.g., at least one) elements selected from the group consisting of F, P, and S.

[0122] For example, in Chemical Formula 3, 0.85≤x3≤0.98, 0.01≤y3≤0.14, 0.01≤z3≤0.14, and 0≤w3≤0.14 may be satisfied, or 0.9≤x3≤0.98, 0.01≤y3≤0.09, 0.01≤z3≤0.09, and 0≤w3≤0.09 may be satisfied.

[0123] For example, x3+y3+z3+w3=1.

[0124] The coating CTL may be located on the core COR. The coating CTL may be located on the entire surface of the core COR or at least a portion of the surface. The coating CTL may include cobalt (Co) and aluminum (Al). For example, the elemental composition of the coating CTL may be confirmed by component analysis using energy dispersive spectroscopy (EDS). By including the coating CTL, the positive electrode active material CAM can be structurally stable even after repeated charging and discharging, side reactions on the surface of the core COR can be suppressed or reduced, and the lifespan characteristics of the positive electrode active material CAM at room temperature and high temperature can be improved.

[0125] For example, the cobalt (Co) in the coating CTL may be present in the form of a cobalt-containing compound. For example, the cobalt-containing compound may be cobalt oxide, cobalt hydroxide, cobalt carbonate, complexes thereof, and / or any suitable mixture thereof. For example, in addition to cobalt, the cobalt-containing compound may further include (e.g., contain) other metal elements or non-metal elements. For example, the cobalt-containing compound may further include (e.g., contain) lithium, manganese, and / or nickel. For example, the cobalt-containing compound may be lithium cobalt oxide, etc.

[0126] For example, the aluminum (Al) in the coating CTL may be present in the form of an aluminum-containing compound. For example, the aluminum-containing compound may be aluminum oxide, aluminum hydroxide, aluminum carbonate, complexes thereof, and / or (e.g., any suitable) mixture thereof. For example, in addition to aluminum, the aluminum-containing compound may further include (e.g., contain) other metal elements or non-metal elements. For example, the aluminum-containing compound may further include (e.g., contain) lithium, manganese, and / or nickel. For example, the aluminum-containing compound may be lithium aluminate, etc.

[0127] The coating layer CTL and the core COR can be distinguished by performing depth profiling of the positive electrode active material CAM using a transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS). In the description, in the EDS result showing the cobalt signal (Co signal) obtained by scanning the positive electrode active material CAM in a direction from the outermost surface (e.g., edge) of the cross section toward the center of the positive electrode active material CAM, for example, the point where the cobalt signal (Co signal) shows the fastest decline after the maximum peak can be defined as the boundary between the coating layer CTL and the core COR (see Figure 17C ). For example, the magnitude of the signal may be proportional to the content (eg, amount) of the element. For example, the content (eg, amount) may be atomic %.

[0128] The total content (e.g., amount) of cobalt and aluminum in the coating CTL may be greater than the total content (e.g., amount) of cobalt and aluminum in the core COR. For example, the total content (e.g., amount) of cobalt and aluminum in the coating CTL may be greater than the total content (e.g., amount) of cobalt and aluminum in the lithium nickel composite oxide. For example, the total content (e.g., amount) may be an atomic ratio (i.e., atomic %) based on the total number of atoms in each part (e.g., the coating CTL or the core COR).

[0129] The content (e.g., amount) of cobalt in the coating CTL may be greater than the content (e.g., amount) of cobalt in the core COR. The content (e.g., amount) of aluminum in the coating CTL may be greater than the content (e.g., amount) of aluminum in the core COR. For example, the content (e.g., amount) of cobalt and aluminum in the coating CTL may be greater than the content (e.g., amount) of cobalt and aluminum in the lithium nickel composite oxide. For example, the content (e.g., amount) may be an atomic ratio (i.e., atomic %) based on the total number of atoms in each part (e.g., the coating CTL or the core COR).

[0130] For example, the lithium nickel-based composite oxide may include cobalt, but the content (e.g., amount) of cobalt in the lithium nickel-based composite oxide may be less than the content (e.g., amount) of cobalt in the coating CTL. For example, the content (e.g., amount) may be an atomic ratio (i.e., atomic %) based on the total number of atoms in each part (e.g., the lithium nickel-based composite oxide or the coating CTL). In one or more embodiments, the lithium nickel-based composite oxide may substantially exclude (e.g., not include) aluminum, and thus the content (e.g., amount) of aluminum in the lithium nickel-based composite oxide may be less than the content (e.g., amount) of aluminum in the coating CTL. For example, substantially excluding (e.g., not including) may mean including a content (e.g., amount) of about 100 parts per million (ppm) or less based on the total amount of the lithium nickel-based composite oxide.

[0131] In one or more embodiments, the lithium nickel-based composite oxide may include both cobalt and aluminum (e.g., simultaneously), but the content (e.g., amount) of each of cobalt and aluminum in the lithium nickel-based composite oxide may be less than the content (e.g., amount) of each of cobalt and aluminum in the coating CTL.

[0132] The molar ratio of aluminum to cobalt in the coating CTL (C Al / C Co ) may be from about 0.1 to about 4. For example, the molar ratio of aluminum to cobalt in the coating CTL (C Al / C Co ) may be from about 0.1 to about 3, from about 0.1 to about 1, or from about 0.1 to about 0.5. If (for example, when) the content (for example, amount) of cobalt, the content (for example, amount) of aluminum, and / or the molar ratio (C Al / C Co) satisfies the range described herein, the positive electrode active material CAM can have a long life even after repeated charge and discharge, and the amount of change in resistance can be reduced.

[0133] refer to Figure 8 , the coating layer CTL may include a first coating layer CTL1 and a second coating layer CTL2.

[0134] The first coating layer CTL1 and the second coating layer CTL2 can be distinguished by depth profiling the positive electrode active material CAM using a transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS). In the description, in the EDS result showing the aluminum signal (Al signal) obtained by scanning the positive electrode active material CAM in a direction from the outermost surface (e.g., edge) toward the center of the cross section of the positive electrode active material CAM, the point where the aluminum signal (Al signal) shows the fastest drop after the maximum peak can be defined as the boundary between the first coating layer CTL1 and the second coating layer CTL2 (see Figure 17B For example, the intensity (e.g., amplitude or size) of the signal may be proportional to the content (e.g., amount). For example, the content (e.g., amount) may be an atomic ratio (i.e., atomic %) based on the total number of atoms in the respective parts (e.g., the first coating layer CTL1 or the second coating layer CTL2).

[0135] The content (e.g., amount) of aluminum in the second coating layer CTL2 may be greater than the content (e.g., amount) of aluminum in the first coating layer CTL1. The content (e.g., amount) of aluminum in the first coating layer CTL1 may be substantially the same as the content (e.g., amount) of aluminum in the core COR. Substantially the same content (e.g., amount) may be defined as: in an EDS result showing an aluminum signal (Al signal) obtained by scanning the positive electrode active material CAM in a direction from the outermost surface to the center thereof, the difference between the average value of the aluminum signal (Al signal) of the first coating layer CTL1 and the average value of the aluminum signal (Al signal) of the core COR is less than about 10%. For example, the content (e.g., amount) may be an atomic ratio (i.e., atomic %) based on the total number of atoms in each portion (e.g., the first coating layer CTL1 or the second coating layer CTL2).

[0136] The first coating layer CTL1 may have a first thickness TKC1. The second coating layer CTL2 may have a second thickness TKC2. The sum of the first and second thicknesses (TKC1+TKC2) may be approximately 25 nanometers (nm) to approximately 60 nm. For example, the sum of the first and second thicknesses (TKC1+TKC2) may be approximately 29 nm to approximately 55 nm or approximately 40 nm to approximately 50 nm. If (for example, when) the sum of the first and second thicknesses (TKC1+TKC2) satisfies the ranges described herein, the positive electrode active material CAM may have a long lifespan and reduce the amount of change in resistance even after repeated charge and discharge.

[0137] The ratio of the second thickness to the first thickness (TKC2 / TKC1) may be about 1 to about 5. For example, the ratio of the second thickness to the first thickness (TKC2 / TKC1) may be about 1.4 to about 3.14 or about 2 to about 3.

[0138] The ratio of the second thickness to the sum of the first and second thicknesses (TKC2 / (TKC1+TKC2)) may be about 0.83 or less. For example, the ratio of the second thickness to the sum of the first and second thicknesses (TKC2 / (TKC1+TKC2)) may be about 0.5 to about 0.83, about 0.6 to about 0.80, or about 0.65 to about 0.8.

[0139] The ratio of the sum of the first thickness and the second thickness to the second thickness ((TKC1+TKC2) / TKC2) may be about 1.2 or greater. For example, the ratio of the sum of the first thickness and the second thickness to the second thickness ((TKC1+TKC2) / TKC2) may be about 1.2 to about 2, about 1.25 to about 1.7, or about 1.25 to about 1.5.

[0140] If (for example, when) the ratio of the second thickness to the first thickness (TKC2 / TKC1), the ratio of the second thickness to the sum of the first thickness and the second thickness (TKC2 / (TKC1+TKC2)), and / or the ratio of the sum of the first thickness and the second thickness to the second thickness ((TKC1+TKC2) / TKC2) satisfies the range described herein, the positive electrode active material CAM can have a long life and the amount of change in resistance can be reduced even when charging and discharging are repeated.

[0141] The first thickness TKC1 may be a value obtained by subtracting the second thickness TKC2 from the sum of the first thickness and the second thickness (TKC1+TKC2). The second thickness TKC2 may be about 20 nm to about 40 nm. For example, the second thickness TKC2 may be about 25 nm to about 40 nm, about 30 nm to about 40 nm, or about 30 nm to about 35 nm. If (for example, when)

[0142] When the second thickness TKC2 satisfies the range described herein, the positive electrode active material CAM may have a long lifespan even if charge and discharge are repeated, and the amount of change in resistance may be reduced.

[0143] In addition to the coating CTL, the positive electrode active material CAM may be further included in the primary particles (see Figure 7 The grain boundary coating may be present in the interior of the positive electrode active material CAM. The grain boundary coating may be formed by the primary particles (see FIG. 1 ) along the interior of the positive electrode active material CAM (e.g., secondary particles) Figure 7 The positive electrode active material CAM may be formed by coating the interface between the positive electrode active material CAM and the PRP in the positive electrode active material CAM. For example, the grain boundary coating may refer to a coating applied on the grain boundaries inside the positive electrode active material CAM. The inside of the positive electrode active material CAM may refer to the entire inside of the positive electrode active material CAM excluding the surface of the positive electrode active material CAM. For example, the inside of the positive electrode active material CAM may refer to a region from (e.g., away from) the outermost surface of the positive electrode active material CAM to a depth of approximately 10 nm throughout the interior (e.g., the center), or a region from a depth of approximately 10 nm to a depth of approximately 2 μm.

[0144] The grain boundary coating may include cobalt (Co) and aluminum (Al). The cobalt (Co) and aluminum (Al) may be uniformly (e.g., substantially uniformly) distributed within the grain boundary coating. For example, the cobalt (Co) and aluminum (Al) may be distributed at different locations within the grain boundary coating or may not be concentrated at one location. For example, as a result of mapping using energy dispersive spectroscopy (EDS), the cobalt and aluminum in the grain boundary coating may be present at substantially the same location.

[0145] Because the positive electrode active material CAM further includes a grain boundary coating, the structural stability is enhanced, a substantially uniform (e.g., and uniform) coating is generated (e.g., exists) on the surface, and the coating content (e.g., amount) on the surface is suitably or properly controlled or selected, thereby improving the initial charge efficiency / discharge efficiency and life characteristics without increasing the resistance.

[0146] refer to Figure 9 , the positive electrode active material CAM may include a first region RG1 and a second region RG2 .

[0147] The first region RG1 may be located at the center of the positive electrode active material CAM. The first region RG1 may be defined as a region of the positive electrode active material CAM excluding the second region RG2.

[0148] The second region RG2 may be located on the outer surface (e.g., edge) of the positive electrode active material CAM. The second region RG2 may be around the first region RG1 (e.g., surrounding the first region RG1). In the description, the second region RG2 may be defined as a region from the outermost surface (e.g., edge) of the positive electrode active material CAM to the depth at which components can be analyzed using energy dispersive spectroscopy (EDS). The depth at which components can be analyzed using energy dispersive spectroscopy (EDS) may be several micrometers (μm). For example, the depth (EDS) at which components can be analyzed using energy dispersive spectroscopy (EDS) may be approximately 1 μm. For example, the second region RG2 may be defined as a region having a thickness TKR of approximately 1 μm in the direction from the outermost surface of the positive electrode active material CAM toward the center of the positive electrode active material CAM.

[0149] The positive electrode active material CAM including the first region RG1 and the second region RG2 may include nickel (Ni), cobalt (Co), and aluminum (Al). For example, both (e.g., simultaneously) the first region RG1 and the second region RG2 may include nickel (Ni), cobalt (Co), and aluminum (Al). In one or more embodiments, the first region RG1 may include nickel (Ni) and cobalt (Co), and the second region RG2 may include nickel (Ni), cobalt (Co), and aluminum (Al).

[0150] The amounts (e.g., contents) of nickel (Ni), cobalt (Co), and aluminum (Al) in the first region RG1 and the second region RG2 can be obtained from the results of energy dispersive spectroscopy (EDS). The amounts (e.g., contents) of nickel (Ni), cobalt (Co), and aluminum (Al) derived from energy dispersive spectroscopy (EDS) (N Ni 、N Co and N Al ) can be expressed in atomic %. The amount (eg, content) of nickel (Ni), cobalt (Co) and aluminum (Al) (N Ni 、N Co and N Al ) can be calculated based on the total amount (e.g., content) (atomic %) (e.g., content) (atomic %) of nickel (Ni), cobalt (Co), and aluminum (Al).

[0151] The content (eg, amount) ratio (N) of nickel to aluminum in the first region RG1 is Ni / N Al ) may be greater than the content (eg, amount) ratio (N Ni / N Al ).

[0152] For example, the content (eg, amount) ratio (N) of nickel to aluminum in the first region RG1 is Ni / N Al ) may be about 45 or more. For example, the content (eg, amount) ratio (N) of nickel to aluminum in the first region RG1 may be about 45 or more. Ni / N Al ) may be at least about 46 (e.g., or greater), for example, about 48 or greater or about 50 or greater, and about 100 or less, about 99 or less, about 98 or less, about 95 or less, about 90 or less, about 85 or less, about 80 or less, about 75 or less, about 70 or less, or about 65 or less.

[0153] For example, the content (eg, amount) ratio (N) of nickel to aluminum in the second region RG2 is Ni / N Al ) may be in the range of about 5 to about 45. For example, the content (eg, amount) ratio (N) of nickel to aluminum in the second region RG2 may be about 5 to about 45. Ni / N Al ) can be about 8 to about 45, about 12 to about 45, or about 15 to about 42.

[0154] If (eg, when) the first region RG1 and / or the second region RG2 each have a content (eg, amount) ratio (N) of nickel to aluminum within the ranges described herein, Ni / N Al )(when), the positive electrode active material CAM can have a long life and reduce the change in resistance even after repeated charge and discharge.

[0155] The cobalt and aluminum (N Co / N Al ) may be about 0.1 or greater. For example, the cobalt and aluminum (N Co / N Al ) may be about 0.5 or more, about 1 or more, or about 2 or more, and about 10 or less, about 8 or less, or about 6 or less. If (for example, when) the cobalt and aluminum (N) of the second region RG2 are Co / N Al ) satisfies the ranges described herein, the positive electrode active material CAM may have a long life and reduce changes in resistance even after repeated charge and discharge.

[0156] The positive electrode 10 and the lithium secondary battery including the positive electrode active material CAM according to one or more embodiments of the present disclosure may have excellent or appropriate life characteristics and may have a small resistance change according to repeated charging and discharging. For example, if (for example, when) (for example, when operating the lithium secondary battery including the positive electrode 10) the charging and discharging cycle is repeated 50 times (times) under 1C / 1C conditions, the positive electrode 10 and the lithium secondary battery including the positive electrode active material CAM according to one or more embodiments of the present disclosure may have a capacity retention rate of about 95% or higher. In some embodiments, even if (for example, when operating the lithium secondary battery including the positive electrode 10) the charging and discharging cycle is repeated 50 times (times) under 1C / 1C conditions, the positive electrode 10 and the lithium secondary battery including the positive electrode active material CAM according to one or more embodiments of the present disclosure may have a resistance change of at most about 60 ohms (Ω) (for example, or less) (for example, about 35Ω or less),

[0157] Preparation method of positive electrode active material CAM

[0158] Figure 10 FIG. 1 is a flow chart for explaining a method for preparing a positive electrode active material CAM according to one or more embodiments of the present disclosure. Figure 11 1 is a flowchart for explaining step (eg, action or task) S100 of a preparation method according to one or more embodiments. Figures 12 to 15 It is a schematic diagram for explaining each step (eg, action or task) of the preparation method.

[0159] refer to Figure 10 The method for preparing the positive electrode active material CAM according to one or more embodiments of the present disclosure may include forming a lithium nickel-based composite oxide ( S100 ) and coating the lithium nickel-based composite oxide.

[0160] Coating the lithium nickel composite oxide may include: forming a first aqueous solution including an aluminum compound and an alkaline compound (S300); mixing the lithium nickel composite oxide and the first aqueous solution to form a mixture (S500); adding a second aqueous solution including a cobalt compound to the mixture (S700); and drying and heat treating (S900).

[0161] refer to Figure 11 , forming the lithium nickel-based composite oxide ( S100 ) may include: forming a nickel-based hydroxide ( S120 ); mixing the nickel-based hydroxide and a lithium raw material ( S140 ); and heat treating ( S160 ).

[0162] The nickel hydroxide may include a transition metal. The transition metal may include nickel (Ni) and further include M of the above Chemical Formula 1. 1 and M 2For example, the nickel hydroxide may include nickel (Ni) and cobalt (Co) as transition metals. For example, the nickel hydroxide may include nickel (Ni), cobalt (Co), and aluminum (Al) as transition metals. In one or more embodiments, the nickel hydroxide may include nickel (Ni), cobalt (Co), and manganese (Mn) as transition metals.

[0163] Nickel hydroxide can be obtained by including a coprecipitation method in the formation of nickel hydroxide (S120). For example, the coprecipitation method may include dissolving a transition metal raw material in a solvent (such as distilled water) to form a solution, and continuously introducing the solution (e.g., a transition metal salt solution) into a reactor together with a chelating agent and / or an alkaline aqueous solution to cause precipitation. After collecting the precipitate in the form of a slurry, the slurry solution may be filtered and dried to obtain nickel hydroxide.

[0164] The transition metal raw material may include a salt of a transition metal described herein. The salt of the transition metal may be a sulfate, a nitrate, an acetate, a halide, a hydroxide, etc., and is not particularly limited as long as it is soluble in a solvent. In one or more embodiments, the transition metal raw material may include a nickel salt, a cobalt salt, and an aluminum salt. In one or more embodiments, the transition metal raw material may include a nickel salt, a cobalt salt, and a manganese salt. The transition metal raw materials may be mixed by adjusting the molar ratio so that the positive electrode active material has high capacity characteristics.

[0165] In mixing the nickel hydroxide and the lithium raw material (S140), the nickel hydroxide and the lithium raw material may be mixed in a certain ratio. For example, the nickel hydroxide and the lithium raw material may be mixed in a molar ratio of about 1:1. The lithium raw material is not particularly limited as long as it is a material commonly used to prepare a positive electrode active material. For example, the lithium raw material may include a lithium salt such as lithium carbonate, lithium nitrate, lithium hydroxide and / or lithium sulfate.

[0166] The mixture of nickel hydroxide and lithium raw material can be heat-treated by placing it in a furnace FRC (S160). The heat treatment temperature may be about 700°C to about 1,000°C. For example, the heat treatment temperature may be about 700°C to about 800°C. The heat treatment may be carried out in an oxidizing atmosphere (such as air and / or oxygen). The heat treatment time may be about 10 hours to about 30 hours. For example, the heat treatment time may be about 10 hours to about 20 hours. In one or more embodiments, for example, prior to the heat treatment, preliminary sintering may be additionally performed at about 150°C to about 800°C.

[0167] In one or more embodiments, a grinding process may be further performed after the heat treatment. Through the grinding process, a lithium nickel-based composite oxide having a desired or appropriate average particle size may be obtained.

[0168] The obtained lithium nickel composite oxide can be compared with the reference Figure 7The core CORs described herein have substantially the same components and compositions. Substantially the same composition may mean that the difference between two different compositions is within about 10%. For example, the lithium nickel composite oxide may be a compound represented by Chemical Formula 1. For example, the lithium nickel composite oxide may be a compound represented by Chemical Formula 2 or Chemical Formula 3.

[0169] refer to Figures 12 to 15 , can be coated with lithium nickel composite oxide NBO.

[0170] refer to Figure 12 , a first aqueous solution AQ1 including an aluminum compound and a basic compound may be formed ( S300 ).

[0171] The aluminum compound may be an aluminum coating raw material. For example, the aluminum compound may include at least one selected from the group consisting of aluminum sulfate (Al2(SO4)3) and sodium metaaluminate (NaAlO2). However, one or more disclosed embodiments are not limited thereto.

[0172] The aluminum compound may be added so that the molar amount of aluminum relative to the total molar amount of elements other than lithium and oxygen in the lithium nickel composite oxide is about 0.05 mol% to about 2 mol%. For example, the aluminum compound may be added so that the molar amount of aluminum relative to the total molar amount of elements other than lithium and oxygen in the lithium nickel composite oxide is about 0.05 mol% to about 1.5 mol%, about 0.05 mol% to about 1 mol%, about 0.1 mol% to about 1 mol%, about 0.2 mol% to about 0.8 mol%, or about 0.5 mol% to about 0.8 mol%. If (for example, when) the amount of the added aluminum compound satisfies the range described herein, the positive electrode active material finally prepared may have a long life and may reduce the amount of change in resistance.

[0173] In one or more embodiments, the alkaline compound may include at least one selected from the group consisting of sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), and ammonia (NH 3 ). However, the alkaline compound may be a compound that can be used for precipitation and is not particularly limited to the illustrated examples.

[0174] For example, the first aqueous solution AQ1 may include anionic aluminum. By first generating anionic aluminum, the positive electrode active material finally prepared may have a long lifespan and may reduce the amount of change in resistance.

[0175] The first aqueous solution AQ1 and the lithium nickel-based composite oxide NBO may be mixed to form a mixture MXR1 ( S500 ). The mixing may be performed using a stirrer.

[0176] The mixing may be performed for about 3 minutes to about 30 minutes. However, one or more embodiments of the present disclosure are not limited to the described time, and the time to form a substantially uniform mixture MXR1 may be sufficient.

[0177] refer to Figure 13 , a second aqueous solution AQ2 may be added to the mixture MXR1 (S700). The second aqueous solution AQ2 may include a cobalt compound.

[0178] The cobalt compound may be a cobalt coating raw material. For example, it may include at least one selected from the group consisting of cobalt nitrate, cobalt sulfate, cobalt oxide, cobalt hydroxide, and cobalt carbonate. However, one or more embodiments of the present disclosure are not particularly limited thereto.

[0179] The cobalt compound may be added such that the molar amount of cobalt is about 0.25 mol% to about 4 mol% relative to the total molar amount of elements other than lithium and oxygen in the lithium nickel composite oxide. For example, the cobalt compound may be added such that the molar amount of cobalt is about 0.5 mol% to about 4 mol%, about 1 mol% to about 4 mol%, about 1 mol% to about 3 mol%, or about 1.2 mol% to about 3 mol% relative to the total molar amount of elements other than lithium and oxygen in the lithium nickel composite oxide. If (for example, when) the amount of the cobalt compound added satisfies the range described herein, the positive electrode active material ultimately prepared may have a long life and may reduce the amount of change in resistance.

[0180] The molar ratio of the amount of aluminum in the added aluminum compound to the amount of cobalt in the added cobalt compound may be about 0.1 to about 4. For example, the molar ratio of the amount of aluminum in the added aluminum compound to the amount of cobalt in the added cobalt compound may be about 0.1 to about 3, about 0.1 to about 1, about 0.1 to about 0.7, or about 0.1 to about 0.5. If (for example, when) the molar ratio of the amount of aluminum in the added aluminum compound to the amount of cobalt in the added cobalt compound satisfies the range described herein, the ultimately prepared positive electrode active material may have a long life and may reduce the amount of change in resistance.

[0181] For example, the second aqueous solution AQ2 may be dropped into the mixture MXR1. For example, the cobalt coating raw material in the second aqueous solution AQ2 may be slowly (eg, dropwise) supplied into the mixture MXR1.

[0182] The second aqueous solution AQ2 may be added for about 5 minutes to about 1 hour. For example, the second aqueous solution AQ2 may be added for about 10 minutes to about 50 minutes or about 20 minutes to about 40 minutes.

[0183] If (eg, when) necessary, a precipitant, a pH adjuster, etc. may be further added to the mixture MXR1.

[0184] In this step (e.g., action or task), the precipitation of aluminum and cobalt may occur simultaneously (e.g., synchronously). Aluminum and cobalt may exist in the form of an aluminum-containing compound and a cobalt-containing compound, respectively. For example, the aluminum-containing compound may include aluminum hydroxide, etc., and the cobalt-containing compound may include cobalt hydroxide, etc. However, one or more embodiments of the present disclosure are not limited thereto. Aluminum and cobalt may be precipitated on the surface of the lithium nickel composite oxide NBO. Accordingly, the mixture MXR2 may include a lithium nickel composite oxide NBO on which aluminum and cobalt are precipitated.

[0185] The coating of the lithium nickel composite oxide NBO according to one or more embodiments of the present disclosure may be wet coating. By wet coating according to the steps described herein, cobalt and aluminum can be coated not only simultaneously (e.g., synchronously) and uniformly (e.g., substantially uniformly) on the surface of the lithium nickel composite oxide NBO, but also on the grain boundaries of the primary particle surfaces.

[0186] The coating of the lithium nickel composite oxide NBO according to one or more embodiments of the present disclosure may be performed by first adding an aluminum compound and then adding a cobalt compound. As a result, a coating having the structure described herein may be formed ( Figure 7 CTL), and the positive electrode active material finally prepared can have a long life and can reduce the amount of change in resistance.

[0187] refer to Figure 14 and Figure 15 The mixture MXR2 can be dried and heat treated to form the positive electrode active material described herein ( Figure 7 CAM)(S920 and S940).

[0188] The mixture MXR2 can be filtered to remove the solvent and dried to obtain a dry product DPR (S920). The drying temperature can be about 100°C to about 300°C. The drying time can be about 5 hours to about 15 hours. By drying, the residual solvent can be removed.

[0189] The dried product DPR can be placed in a furnace FRC and heat treated (S940). The heat treatment temperature may be about 650°C to about 1000°C. For example, the heat treatment temperature may be about 650°C to about 900°C or about 650°C to about 800°C. The heat treatment time may be about 5 hours to about 30 hours. For example, the heat treatment time may be about 10 hours to about 24 hours or about 10 hours to about 20 hours. If (for example, when) the heat treatment conditions meet the range described herein (when), the positive electrode active material finally prepared may have a long life and reduce the amount of change in resistance.

[0190] In one or more embodiments, a lithium raw material may be additionally added before heat treatment, and heat treated. For example, the lithium raw material may include a lithium salt, such as lithium carbonate, lithium nitrate, lithium hydroxide and / or lithium sulfate. For example, a lithium raw material may be added so that the molar number of lithium is about 0.1 mol% to about 10 mol% relative to the total molar number of elements other than lithium and oxygen in the lithium nickel composite oxide. For example, a lithium raw material may be added so that the molar number of lithium is about 0.1 mol% to about 8 mol% or about 1 mol% to about 6 mol% relative to the total molar number of elements other than lithium and oxygen in the lithium nickel composite oxide. If (for example, when) a lithium raw material is added in the range described herein, the surface of the lithium nickel composite oxide damaged during the coating process can be repaired. Therefore, the positive electrode active material ultimately prepared can have a long life and can reduce the amount of change in resistance.

[0191] Terms such as "substantially," "about," and "approximately" are used as relative terms, not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art. They may include the stated value and an acceptable range of deviation determined by one of ordinary skill in the art to take into account the limitations and errors associated with the measurement of that quantity. For example, "about" may refer to one or more standard deviations of the stated value, or ±30%, ±20%, ±10%, or ±5% of the stated value.

[0192] The numerical ranges disclosed herein include and are intended to disclose all subranges of the same numerical precision. For example, the range of "1.0 to 10.0" includes all subranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Therefore, the applicant reserves the right to amend this specification (including the claims) to explicitly set forth any subranges included within the ranges explicitly set forth herein.

[0193] Hereinafter, the present disclosure will be described in more detail through examples. However, the examples are intended to illustrate the present disclosure, and the scope of the present disclosure is not limited to the examples.

[0194] Example

[0195] Example 1

[0196] Preparation Example 1: Formation of lithium nickel composite oxide

[0197] Nickel sulfate (NiSO4·6H2O), cobalt sulfate (CoSO4·7H2O) and aluminum sulfate (Al2(SO4)3) as raw materials of nickel hydroxide are dissolved in distilled water as a solvent at a Ni:Co:Al molar ratio of about 96.5:2:1.5 to prepare a mixture solution of the metal raw materials. In order to form a complex compound, a dilute ammonia solution (NH4OH) and sodium hydroxide (NaOH) as a precipitant are prepared. The mixture solution of the metal raw materials, ammonia solution and sodium hydroxide is introduced into a reactor. Sodium hydroxide is introduced to maintain the pH of the mixture in the reactor. While stirring the mixture in the reactor, the reaction is carried out for about 20 hours. The product is filtered, rinsed and dried to obtain nickel hydroxide (Ni 0.965 Co 0.020 Al 0.015 (OH)2).

[0198] Nickel hydroxide and anhydrous lithium hydroxide (LiOH) are mixed in a molar ratio of about 1:1.03, so that the molar ratio of lithium to the total metal amount of nickel hydroxide is about 1.03. The mixture is heat-treated at a temperature of about 750° C. in an oxygen atmosphere for about 15 hours to form a lithium nickel composite oxide (LiNi 0.965 Co 0.020 Al 0.015 The lithium nickel-based composite oxide includes (is formed of) secondary particles in which primary particles are aggregated and have an average particle diameter of about 12 micrometers (μm).

[0199] Preparation Example 2: Coating of lithium nickel composite oxide

[0200] A first aqueous solution containing aluminum sulfate (Al2(SO4)3·16H2O) and sodium hydroxide (NaOH) is formed. A lithium nickel composite oxide is added to the first aqueous solution. In this case, aluminum sulfate is added so that the molar number (e.g., molar amount) of aluminum relative to the total molar number (e.g., molar amount) of elements other than lithium and oxygen in the lithium nickel composite oxide is about 0.5 mol%. The mixture of the first aqueous solution and the lithium nickel composite oxide is stirred for about 5 minutes. A second aqueous solution containing cobalt sulfate (CoSO4·7H2O) is added dropwise to the mixture for about 30 minutes. In this case, cobalt sulfate is added so that the molar number (e.g., molar amount) of cobalt relative to the total molar number of elements other than lithium and oxygen in the lithium nickel composite oxide is about 2 mol%. The ratio of the molar number of aluminum in the added aluminum sulfate to the molar number of cobalt in the added cobalt sulfate is about 0.25. The mixture is filtered and dried at a temperature of about 190°C for about 10 hours to obtain a dry product. About 6 mol% lithium hydroxide (LiOH) is mixed with the dry product. The mixture was heat-treated at a temperature of about 650° C. for about 15 hours to obtain a positive electrode active material.

[0201] To summarize Example 1, nickel sulfate, cobalt sulfate, and aluminum sulfate were dissolved in distilled water at a Ni:Co:Al molar ratio of 96.5:2:1.5 to prepare a metal mixture solution. The solution was reacted with ammonia and sodium hydroxide to form nickel hydroxide (Ni 0.965 Co 0.020 Al 0.015 (OH)2). The nickel hydroxide and lithium hydroxide were then mixed in a molar ratio of 1:1.03 and heat-treated at 750°C for 15 hours in an oxygen atmosphere to form a lithium nickel composite oxide (LiNi 0.965 Co 0.020 Al 0.015 O2). The lithium nickel-based composite oxide is composed of secondary particles in which (for example, in each of the secondary particles) primary particles are aggregated and the average particle diameter is 12 μm.

[0202] For coating, an aqueous solution of aluminum sulfate and sodium hydroxide was prepared and a lithium-nickel composite oxide was added. Aluminum sulfate was added to obtain 0.5 mol% aluminum relative to the total molar amount of elements in the lithium-nickel composite oxide, excluding lithium and oxygen, and cobalt sulfate was added dropwise over 30 minutes to obtain 2 mol% cobalt, with a molar ratio of aluminum to cobalt of 0.25. The mixture was filtered, dried at 190°C for 10 hours, and then mixed with 6 mol% lithium hydroxide. This final mixture was heat-treated at 650°C for 15 hours to obtain a positive electrode active material comprising secondary particles formed by the aggregation of primary particles.

[0203] Example 2

[0204] The process was carried out in substantially the same manner as in Example 1, except that cobalt sulfate and aluminum sulfate were added so that the ratio of the number of moles of aluminum in the added aluminum sulfate to the number of moles of cobalt in the added cobalt sulfate was about 3.

[0205] Example 3

[0206] The process was carried out in substantially the same manner as in Example 1, except that cobalt sulfate and aluminum sulfate were added so that the ratio of the number of moles of aluminum in the added aluminum sulfate to the number of moles of cobalt in the added cobalt sulfate was about 1.

[0207] Example 4

[0208] The process was carried out in substantially the same manner as in Example 1, except that cobalt sulfate and aluminum sulfate were added so that the ratio of the number of moles of aluminum in the added aluminum sulfate to the number of moles of cobalt in the added cobalt sulfate was about 0.5.

[0209] Example 5

[0210] The process was carried out in substantially the same manner as in Example 1, except that cobalt sulfate and aluminum sulfate were added so that the ratio of the number of moles of aluminum in the added aluminum sulfate to the number of moles of cobalt in the added cobalt sulfate was about 0.17.

[0211] Comparative Example 1

[0212] A positive electrode active material coated with only cobalt was prepared.

[0213] The lithium nickel composite oxide of Preparation Example 1 was added to an aqueous solution containing about 6 wt % of cobalt sulfate (CoSO 4 ·7H 2 O) and stirred. In this case, the lithium nickel composite oxide was added so that the molar number (e.g., molar amount) of cobalt relative to the total molar number of elements other than lithium and oxygen in the lithium nickel composite oxide was about 2 mol %. Sodium hydroxide (NaOH) was added dropwise to the mixture solution. As a result, the ratio of the molar number of aluminum in the added aluminum sulfate to the molar number of cobalt in the added cobalt sulfate was about 0. Thereafter, filtration, drying, and heat treatment were performed in substantially the same manner as in Example 1.

[0214] Fabrication of positive electrode

[0215] A positive electrode active material slurry was prepared by mixing about 96 wt% of a positive electrode active material, about 2 wt% of a polyvinylidene fluoride binder, and about 2 wt% of a carbon nanotube conductive material in an N-methylpyrrolidone solvent. The positive electrode active material slurry was applied to an aluminum current collector, dried, and roll-pressed to produce a positive electrode.

[0216] Manufacturing of lithium secondary batteries

[0217] A positive electrode and a lithium metal counter electrode were used, with a polyethylene / polypropylene multilayer separator interposed between them. A solution of approximately 1.0 molar (M) LiPF6 lithium salt in a mixed solvent of ethylene carbonate and diethyl carbonate (about 50:50 by volume) was used as the electrolyte. A coin half-cell was formed by injecting the electrolyte.

[0218] Table 1

[0219]

[0220]

[0221] Experimental Example 1: Analysis of the Structure and Composition of Positive Electrode Active Material 1

[0222] Figure 16 Explained are the results of mapping the cross section of the positive electrode active material according to Example 1 using a transmission electron microscope (TEM) image and energy dispersive spectroscopy (EDS).

[0223] refer to Figure 16 The positive electrode active material according to Example 1 includes a coating on the core, and the coating includes cobalt and aluminum (e.g., simultaneously). In some embodiments, the positive electrode active material according to Example 1 includes a grain boundary coating, and the grain boundary coating includes cobalt and aluminum (e.g., simultaneously). As a result of mapping the grain boundary coating, cobalt and aluminum are shown to be uniformly (e.g., substantially uniformly) present in the grain boundary coating, and the cobalt and aluminum in the grain boundary coating are present at substantially the same positions.

[0224] Figures 17A to 17C The depth analysis results of the cross section of the positive electrode active material according to Example 1 were obtained using a transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS). Figure 17B and Figure 17C It is along Figure 17A The arrows in the figure show the depth profile results from the outside to the center.

[0225] refer to Figures 17A to 17C The aluminum signal (Al signal) shows the fastest drop point after the maximum peak at about 31 nanometers (nm) outside, and the cobalt signal (Co signal) shows the fastest drop point after the maximum peak at about 40 nm outside. For example, the thickness of the second coating layer (e.g., on the first coating layer) is about 31 nm, and the thickness of the first coating layer (e.g., on the core) is about 9 nm.

[0226] Experimental Example 2: Analysis of the Structure and Composition of Positive Electrode Active Material 2

[0227] The components of the positive electrode active materials according to Examples 1 to 5 and Comparative Example 1 were analyzed using energy dispersive spectroscopy (EDS), and the results are shown in Table 2. The amounts (e.g., contents) (atomic %) of nickel (Ni), cobalt (Co), and aluminum (Al) obtained by energy dispersive spectroscopy (EDS) are expressed as N, N, and N, respectively. Ni 、N Co and N Al , and the amount ratio between the contents of nickel (Ni), cobalt (Co) and aluminum (Al) is calculated and expressed as N Ni / N Al and N Co / N Al The results of Examples 1 to 5 and Comparative Example 1 are the results in the second region RG2 of the positive electrode active material. The N in the first region RG1 of Examples 1 to 5 is Ni 、N Co 、N Al 、N Ni / N Al and N Co / N Al The values ​​are substantially the same as those of the lithium nickel composite oxide of Preparation Example 1.

[0228] Table 2

[0229]

[0230]

[0231] Experimental Example 3: Performance Evaluation of Lithium Secondary Batteries

[0232] The charge and discharge efficiency, capacity retention rate, and DC resistance of the lithium secondary batteries including the positive electrode active materials according to Examples 1 to 5 and Comparative Example 1 were evaluated.

[0233] The coin cell cells according to the embodiment and the comparative example were initially charged under constant current (about 0.2 coulomb (C)) and constant voltage (about 4.25V, about 0.05C cut-off) conditions, paused for about 10 minutes, and then discharged under constant current (about 0.2C) conditions until about 3.0V for initial charge and discharge. After that, the charge and discharge were repeated 50 times at about 1C / 1C. The efficiency (%) as the ratio of the initial discharge capacity to the initial charge capacity was calculated. The capacity retention rate as the ratio of the discharge capacity of each cycle (the 25th cycle and the 50th cycle) to the initial discharge capacity was calculated.

[0234] The DC resistance (DC-IR = ΔV / ΔI) was calculated from the ratio of the average voltage change (ΔV) to the average current change (ΔI) during constant current discharge, and the average value was expressed as the resulting value. The difference between the DC resistance in the first cycle and the DC resistance in the 50th cycle was expressed as the resistance change. Furthermore, the DC-IR change (%) was calculated as [(DC resistance in the 50th cycle - DC resistance in the first cycle) / DC resistance in the first cycle] × 100%.

[0235] The results are shown in Table 3, with Examples 1 to 5 designated as EX 1 to EX 5 and Comparative Example 1 designated as CE 1.

[0236] Table 3

[0237]

[0238] Referring to Table 3, it was confirmed that the lithium secondary batteries including the positive electrode active materials according to Examples 1 to 5 had excellent or appropriate capacity retention and small resistance change according to repeated charge and discharge.

[0239] The positive electrode active material according to one or more disclosed embodiments, and the positive electrode and lithium secondary battery including the same have high capacity, long life, and low resistance change according to repeated charge and discharge.

[0240] The battery manufacturing device, battery management system (BMS) device and / or any other related device or component according to the embodiments of the present disclosure described herein can be implemented using any appropriate hardware, firmware (e.g., a dedicated integrated circuit), software, or a combination of software, firmware, and hardware. For example, the components of the device can be formed on an integrated circuit (IC) chip or on a separate IC chip. In addition, the components of the device can be implemented on a flexible printed circuit film, a tape carrier package (TCP), or a printed circuit board (PCB), or formed on a substrate. In addition, the various components of the device can be processes or threads running on one or more processors in one or more computing devices, executing computer program instructions and interacting with other system components to perform the functions described herein. The computer program instructions are stored in a memory, which can be implemented in the computing device using a standard memory device, such as, for example, a random access memory (RAM). The computer program instructions can also be stored in other non-transitory computer-readable media (such as, for example, a CD-ROM, a flash drive, etc.). Moreover, those skilled in the art will recognize that, without departing from the scope of the present disclosure, the functions of the computing device can be combined or integrated into a single computing device, or the functions of the dedicated computing device can be distributed on one or more other computing devices.

[0241] In view of the overall content of the present disclosure, those skilled in the art will recognize that each appropriate feature of the embodiments of the present disclosure may be combined in part or in whole or in combination with each other, and may be technically interlocked and operated in one or more appropriate manners, and unless otherwise described or implied, each embodiment may be implemented independently of each other or in combination with each other in any appropriate manner.

[0242] Although one or more embodiments of the present disclosure have been described, it should be understood that the present disclosure should not be limited to these embodiments, but rather one or more appropriate changes and modifications may be made by one of ordinary skill in the art within the spirit and scope of the claims and their equivalents. Therefore, the foregoing embodiments should be understood as illustrative and not limiting the present disclosure in any way.

Claims

1. A positive electrode active material comprising: Lithium nickel composite oxides, including nickel, cobalt and aluminum, The positive electrode active material includes: a first region; and a second region, wherein the second region is around the first region and has a thickness of 1 micrometer in a direction from the outermost surface of the positive electrode active material to the center of the positive electrode active material, and The amount ratio of nickel to aluminum in the second region is N Ni / N Al 5 to 45.

2. The positive electrode active material according to claim 1, wherein the amount ratio of cobalt to aluminum in the second region is N Co / N Al It is 0.1 to 10.

3. The positive electrode active material according to claim 1, wherein the amount ratio of nickel to aluminum in the first region is N Ni / N Al greater than the nickel to aluminum ratio N of the second region Ni / N Al .

4. The positive electrode active material according to claim 1, wherein the amount ratio of nickel to aluminum in the first region is N Ni / N Al At least 45.

5. The positive electrode active material according to claim 1, wherein the positive electrode active material comprises: a core comprising the lithium nickel composite oxide; as well as A coating is on the core and includes cobalt and aluminum. 6 . The positive electrode active material according to claim 5 , wherein the core is a secondary particle, and the secondary particle is an aggregate of primary particles.

7. The positive electrode active material according to claim 5, wherein the core comprises cobalt, and The core has a cobalt content that is less than the coating content.

8. The positive electrode active material according to claim 5, wherein the molar ratio of aluminum to cobalt in the coating is C Al / C Co It is 0.1 to 4.

9. The positive electrode active material according to claim 5, wherein the coating layer comprises: a first coating on the core; and a second coating layer on the first coating layer, and The amount of aluminum in the second coating layer is greater than the aluminum content in the first coating layer. 10 . A positive electrode comprising a positive electrode current collector and a positive electrode active material layer, wherein the positive electrode active material layer comprises the positive electrode active material according to claim 1 .

11. A battery, wherein the battery comprises the positive electrode active material according to any one of claims 1 to 9, and The battery is a lithium secondary battery.

12. The battery of claim 11, having a capacity retention rate of at least 95% and a resistance change of at most 60 ohms when the battery is operated under 1C / 1C conditions for 50 cycles of charge and discharge.

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