Positive electrode active material for rechargeable lithium battery, method of manufacturing positive electrode active material, and rechargeable lithium battery including the same

Abstract

A positive electrode active material, a method of manufacturing the same, and a rechargeable lithium battery are provided. The positive electrode active material includes a first particle including a compound represented by Chemical Formula 1 and having a first average particle diameter. A ratio (ID / IG) of an intensity (ID) of a D peak at a wavenumber of about 1340 + / -10 cm <-1 > in a Raman spectrum obtained from Raman spectroscopy to an intensity (IG) of a G peak at a wavenumber of about 1590 + / -10 cm <-1 > in a Raman spectrum obtained from Raman spectroscopy is in a range of about 0.5 to about 1.5. Chemical formula 1Lia1Fex1B1y1PO4

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0053600, filed on April 22, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] According to one or more embodiments, the present disclosure relates to a positive electrode active material for a rechargeable lithium battery, a method for manufacturing the positive electrode active material, and a rechargeable lithium battery including the positive electrode active material. For example, one or more embodiments relate to a positive electrode active material including an olivine-based lithium compound, a method for manufacturing the positive electrode active material, and a rechargeable lithium battery including the positive electrode active material. Background Art

[0004] Recently, the rapid popularization and expansion of battery-powered and / or battery-using electronic devices (such as mobile phones, laptop computers, etc.) and / or electric vehicles has driven a rapid increase in demand for rechargeable lithium batteries equipped with or provided with relatively high energy density and high capacity. Consequently, intensive research has been conducted to improve the performance of rechargeable lithium batteries, for example, as a driving power source for hybrid and / or electric vehicles, and / or as an energy storage power source, for example, for civilian energy storage (e.g., power walls).

[0005] Rechargeable lithium batteries include a positive electrode, a negative electrode, and an electrolyte. The positive electrode and the negative electrode each include an active material configured for the intercalation and deintercalation of lithium ions. When lithium ions are intercalated and deintercalated during the charging and discharging processes, the battery generates electrical energy due to the oxidation and reduction (i.e., redox) reactions that occur. Summary of the Invention

[0006] One or more aspects relate to positive electrode active materials having high electrical conductivity and excellent or suitable electrochemical properties.

[0007] One or more aspects relate to rechargeable lithium batteries having high electrical conductivity and excellent or suitable electrochemical properties.

[0008] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the embodiments presented herein.

[0009] According to one or more embodiments, the positive electrode active material may include first particles including a compound expressed (eg, represented by) Chemical Formula 1 and having a first average particle size.

[0010] The first particles are configured such that the intensity of the D band peak (I D) and the intensity of the G band peak (I G ) ratio (I D / I G ) may be in the range of about 0.5 to about 1.5. In the Raman spectrum obtained from the Raman spectroscopy, the D band peak and the G band peak may appear at about 1340 ± 10 cm2, respectively. -1 ) and about 1590±10cm -1 The wave number of .

[0011] Chemical formula 1

[0012] Li a1 Fe x1 B1 y1 PO4

[0013] In Chemical Formula 1, 0.8≤a1≤1.2, 0.950≤x1≤0.999, 0≤y1≤0.05, and B1 may be at least one element selected from Ti, Al, Mg, Zr, V, Zn, Nb, K, Y, B, and Cu.

[0014] According to one or more embodiments, a method of manufacturing a positive electrode active material may include: forming a mixture by mixing an iron phosphate precursor, a lithium source, and a carbon source; drying the mixture; and preparing first particles by calcining the dried mixture.

[0015] The first particles may include a compound expressed (eg, represented by) Chemical Formula 1.

[0016] The first particles may be configured such that the intensity of the D band peak (I D ) and the intensity of the G band peak (I G ) ratio (I D / I G ) is in the range of about 0.5 to about 1.5. In the Raman spectrum obtained from Raman spectroscopy, the D band peak and the G band peak can appear at about 1340±10 cm -1 and about 1590±10cm -1 The wave number of .

[0017] Chemical formula 1

[0018] Li a1 Fe x1 B1 y1 PO4

[0019] In Chemical Formula 1, 0.8≤a1≤1.2, 0.950≤x1≤0.999, 0≤y1≤0.05, and B1 may be at least one element selected from Ti, Al, Mg, Zr, V, Zn, Nb, K, Y, B, and Cu.

[0020] According to one or more embodiments of the present disclosure, a rechargeable lithium battery includes a positive electrode active material. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. In the drawings:

[0022] Figure 1 Illustrated is a simplified conceptual diagram showing a rechargeable lithium battery according to one or more embodiments of the present disclosure.

[0023] Figures 2-5 Illustrated are each a simplified diagram showing a rechargeable lithium battery according to one or more embodiments, Figure 2 showing a cylindrical battery, Figure 3 showing a prismatic battery, and Figure 4 Figure 5 and

[0024] Figure 6 Figure 7 Illustrated is a magnified view showing a positive electrode active material layer of a rechargeable lithium battery according to one or more embodiments of the present disclosure.

[0025] Figure 8 Illustrated is a flowchart showing a method of manufacturing a positive electrode active material according to one or more embodiments of the present disclosure.

[0026] Figure 9A Figure 9B Illustrated is an SEM image showing a positive electrode active material according to one or more embodiments of the present disclosure.

[0027] Figures 10A-10C Illustrated is a TEM image showing a positive electrode active material according to one or more embodiments of the present disclosure and a comparative example.

[0028] Figure 11 Illustrated is a graph showing measurement results of Raman spectroscopic analysis of a positive electrode active material according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0029] ​​​Hereinafter, the embodiments of the present disclosure will be described clearly and in more detail, which are sufficient for those skilled in the art to easily practice the present disclosure. 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 attached drawings. However, it should be noted that the present disclosure is not limited to the following example embodiments, and can be implemented in one or more appropriate forms. Rather, the example embodiments are provided only to disclose the embodiments of the present disclosure and to fully enable those skilled in the art to understand the scope of the present disclosure.

[0030] In this description, it will be understood that, if (for example, when) an element or component is referred to as being "on" another element or component, it can be directly on the other element or component, or an intervening element can be present between the two. In contrast, if (for example, when) an element or component is referred to as being "directly on" another element or component, there is no intervening element present. In the drawings, the size (for example, thickness) of some components is exaggerated for effective explanation of the technology. The same reference numbers are used throughout the drawings to refer to the same elements, and repetitive description thereof can not be provided in the specification.

[0031] Unless specifically stated otherwise in the description, expressions of the form (for example, "a," "an," and / or "the") can include plural forms (for example, "at least one") unless the context clearly indicates otherwise. In some embodiments, the phrase "A or B" can indicate "A but not B," "B but not A," and "A and B," unless specifically stated otherwise. As used in this description, the terms "comprises," "includes," "comprising," "including," "comprise," "include," "have," "has," and / or "having" are intended to indicate that there is presence of the expressed aspect, number, step (for example, action or task), element, and / or combination (for example, any appropriate combination), and does not exclude or preclude the presence or addition of one or more other features, numbers, steps (for example, actions or tasks), elements, components, and / or combinations (for example, any appropriate combination).

[0032] As used herein, the term "combination thereof" can refer to a mixture, a stack, a composite, a copolymer, an alloy, a blend, or a reaction product.

[0033] In one or more embodiments, the term "layer" in this document includes not only a shape formed on an entire surface if (for example, when) viewed from a plan view, but also a shape formed on a partial surface.

[0034] It will be understood that, although the terms“first,”“second,”“third,” etc. can be used herein to describe one or more respective elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus,“a first element, component, region, layer or section described herein could be called a second element, component, region, layer or section without departing from the teachings set forth herein.

[0035] 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,” when preceding the

[0036] Spatially relative terms, such as“beneath,”“below,”“lower,”“above,”“upper” and the like, can be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. 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 orientations depicted in the figures. For example, if the device in the figures is turned over, elements described as“below” or“beneath” other elements or features would then be oriented“above” or“upper” relative to the other elements or features. Thus, the exemplary term“below” can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative terms used herein interpreted accordingly.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0038] Example embodiments are described herein with reference to cross-sectional illustrations, which are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments described herein are not to be construed as being limited to the particular shapes illustrated herein but are to include deviations in shapes that result from, for example, manufacturing. For example, a region illustrated or described as flat can often have rough and / or nonlinear features. Moreover, an illustrated sharp corner can typically be rounded. Thus, the regions illustrated in the figures are schematic and their shapes are not intended to illustrate the precise shape of a region but are meant to be representative of such regions. Embodiments described herein are not to be construed as being limited to the particular shapes illustrated herein but are to include deviations in shapes that result from, for example, manufacturing.

[0039] The term “may” will be understood to mean “one or more embodiments of the present disclosure” in which some include the described element and others do not. Similarly, optional language such as “can” refers to “one or more embodiments of the present disclosure” in which the corresponding recited item is included in some embodiments and not in others.

[0040] In the context of “consisting essentially of’ indicates that any additional components would not materially affect the chemical, physical, optical, or electrical properties of the subject portion.

[0041] Further, in the present specification, the phrase “in plane” or “plan view” indicates viewing a subject portion from the top, and the phrase “in cross-section” indicates viewing a cross-section formed by cutting the subject portion perpendicularly from the side.

[0042] The term “particle size,” “particle diameter,” as used herein, refers to the average diameter of a particle, if (e.g., when) the particle is spherical, and the average long axis length of a particle, if (e.g., when) the particle is non-spherical. For example, the particle size can be the average particle diameter. In some embodiments, the particle size (D 50 ) refers to the average particle diameter at which the cumulative volume in the particle size distribution is about 50% by volume. The average particle diameter (D 50 ) can be measured by methods widely available to those skilled in the art, for example, by a particle size analyzer, a transmission electron microscope (TEM) image, or a scanning electron microscope (SEM) image. In one or more embodiments, data analysis is performed using a dynamic light scattering measuring device, the number of particles in each particle size range is counted, and then the average particle diameter (D 50 ) value can be obtained by calculation therefrom. Alternatively, a laser scattering method can be used to measure the average particle diameter (D 50). In the laser scattering method, the target particles are dispersed in a dispersion solvent, introduced into a laser scattering particle measuring device (for example, MT3000 commercially available from Microtrac, Inc.), irradiated with 28 kHz ultrasonic waves at a power of 60 W, and then the average particle diameter (D 50 ) is calculated in the measuring device at a particle size distribution standard of 50% by volume.

[0043] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to one or more embodiments of the present disclosure is illustrated. Referring to Figure 1 , the rechargeable lithium battery can include a positive electrode 10, a negative electrode 20, a separator 30, and an electrolyte ELL.

[0044] The positive electrode 10 and the negative electrode 20 can be spaced apart and / or separated (for example, spaced apart or separated) from each other by the separator 30. The separator 30 can be disposed between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20, and the separator 30 can be in contact with the electrolyte ELL. The positive electrode 10, the negative electrode 20, and the separator 30 can be impregnated in the electrolyte ELL.

[0045] The electrolyte ELL can be a medium through which lithium ions are transported between the positive electrode 10 and the negative electrode 20. In the electrolyte ELL, lithium ions can move toward one of the positive electrode 10 and the negative electrode 20 through the separator 30.

[0046] The positive electrode 10

[0047] The positive electrode 10 for the rechargeable lithium battery can 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 can include a positive electrode active material, and further include a binder and / or a conductive material. Referring to Figure 6 , the positive electrode active material layer AML1 according to one or more embodiments of the present disclosure will be described in more detail below. An aluminum (Al) foil can be used as the positive electrode current collector COL1, but the present disclosure is not limited thereto.

[0048] The negative electrode 20

[0049] The negative electrode 20 for the rechargeable lithium battery can 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 can include a negative electrode active material, and can further include a binder and / or a conductive material.

[0050] For example, the negative electrode active material layer AML2 can 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.

[0051] The binder can be used to improve adhesion of the negative electrode active material particles to each other, and also to improve adhesion of the negative electrode active material to the negative electrode current collector COL2. The binder can include a non-aqueous binder, an aqueous binder, a dry binder, and / or a combination (e.g., any suitable combination) thereof.

[0052] The non-aqueous binder can include polyvinyl chloride, carboxylated polyvinyl chloride, polyfluoroethylene, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, and / or a combination (e.g., any suitable combination) thereof.

[0053] The aqueous binder can include styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and / or a combination (e.g., any suitable combination) thereof.

[0054] If (e.g., when) the aqueous binder is used as the binder in the negative electrode active material layer AML2, a cellulose-based compound capable of providing viscosity can be further included. The cellulose-based compound can include one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and alkali metal salts thereof. The alkali metal can include Na, K, or Li.

[0055] The dry binder can include a fibrillatable polymeric material, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and / or a combination (e.g., any suitable combination) thereof.

[0056] The conductive material can be used to provide electrical conductivity to the electrode, and any suitable conductive material that does not cause chemical changes in the battery can be used as the conductive material constituting the battery. For example, the conductive material can include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal powder or metal fiber including one or more of copper, nickel, aluminum, and silver; conductive polymer such as polyphenylene derivative; and / or a mixture (e.g., any suitable mixture) thereof.

[0057] The negative electrode current collector COL2 can include a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, a polymer substrate coated with a conductive metal, and / or a combination (e.g., any suitable combination) thereof.

[0058] The negative electrode active material

[0059] The negative electrode active material in the negative electrode active material layer AML2 can include a material that can reversibly intercalate and deintercalate lithium ions, lithium metal, a lithium metal alloy, a material that can dope and / or dedope lithium, and / or a transition metal oxide.

[0060] The material that can reversibly intercalate and deintercalate lithium ions can include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, and / or a combination (e.g., any suitable combination) thereof. For example, the crystalline carbon can include graphite, such as at least one of amorphous, flaky, flake-like, spherical, or fibrous natural and / or artificial graphite, and the amorphous carbon can include soft carbon, hard carbon, meso-phase pitch carbon, and / or calcined coke.

[0061] The lithium metal alloy can include an alloy of lithium and at least one metal selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0062] The material that can dope and / or dedope lithium can include a Si-based negative electrode active material and / or a Sn-based negative electrode active material. The Si-based negative electrode active material can include silicon, a silicon-carbon composite, SiO x (wherein 0 < x ≤ 2), a Si-Q alloy (wherein Q is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element (except Si), a Group 15 element, a Group 16 element, a transition metal, a rare earth element, and / or a combination (e.g., any suitable combination) thereof), and / or a combination (e.g., any suitable combination) thereof. The Sn-based negative electrode active material can include Sn, SnO x (wherein 0 < x ≤ 2) (e.g., SnO2), a Sn-based alloy, a combination (e.g., any suitable combination) thereof.

[0063] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one or more embodiments, the silicon-carbon composite can have a structure in which amorphous carbon is coated on the surface of silicon particles. For example, the silicon-carbon composite can include secondary particles (cores) in which primary silicon particles are aggregated, and an amorphous carbon coating layer (shell) on the surface of the secondary particles. The amorphous carbon can also be located between the primary silicon particles, for example, the primary silicon particles can be coated with amorphous carbon. The secondary particles can be dispersed in an amorphous carbon matrix.

[0064] The silicon-carbon composite can further include crystalline carbon. For example, the silicon-carbon composite can include a core including crystalline carbon and silicon particles, and can further include an amorphous carbon coating layer on a surface of the core.

[0065] The Si-based negative electrode active material or the Sn-based negative electrode active material can be used in combination with the carbon-based negative electrode active material.

[0066] Separator 30

[0067] The separator 30 can be present between the positive electrode 10 and the negative electrode 20, based on the type of the rechargeable lithium battery. The separator 30 can include one or more of a polyethylene separator, a polypropylene separator, and a polyvinylidene fluoride separator, and can have a multi-layer separator such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene triple-layer separator, and a polypropylene / polyethylene / polypropylene triple-layer separator, etc.

[0068] The separator 30 can include a porous substrate and a coating layer on one surface or the opposite surface of the porous substrate, which can include an organic material, an inorganic material, and / or a (e.g., any appropriate) combination thereof.

[0069] The porous substrate can be a polymeric layer including one selected from a polyolefin such as polyethylene and polypropylene, a polyester such as polyethylene terephthalate and polybutylene terephthalate, a polyacetal, a polyamide, a polyimide, a polycarbonate, a polyether ketone, a polyaryletherketone, a polyetherimide, a polyamideimide, a polybenzimidazole, a polyethersulfone, a polyphenylene ether, a cyclic olefin copolymer, a polyphenylene sulfide, a polyethylene naphthalate, a glass fiber, and polytetrafluoroethylene (e.g., Teflon), or can be a copolymer or a mixture including two or more of the previously disclosed materials.

[0070] The organic material can include a polyvinylidene fluoride-based copolymer or a (meth)acrylic-based copolymer.

[0071] The inorganic material can 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 a (e.g., any appropriate) combination thereof, but the disclosure is not limited thereto.

[0072] The organic material and the inorganic material can be mixedly present in one coating layer, or can be present as a stack of a coating layer including the organic material and a coating layer including the inorganic material.

[0073] Electrolyte ELL

[0074] The electrolyte ELL for the rechargeable lithium battery can include a non-aqueous organic solvent and a lithium salt.

[0075] The non-aqueous organic solvent can be used as a medium for transporting ions involved in electrochemical reactions of the battery.

[0076] The non-aqueous organic solvent can include carbonate-based solvents, ester-based solvents, ether-based solvents, ketone-based solvents, alcohol-based solvents, aprotic solvents, and / or combinations (e.g., any appropriate combination) thereof.

[0077] The carbonate-based solvent can include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), and / or butylene carbonate (BC).

[0078] The ester-based solvent can include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolide, mevalonolactone, valerolactone, and / or caprolactone.

[0079] The ether-based solvent can include dibutyl ether, tetraglyme, diglyme, glyme, 2-methyltetrahydrofuran, 2.5-dimethyltetrahydrofuran, and / or tetrahydrofuran. The ketone-based solvent can include cyclohexanone. The alcohol-based solvent can include ethanol and / or isopropanol. The aprotic solvent can include nitriles (such as R-CN, where R is a hydrocarbon group having a C2~C20 linear, branched, or cyclic structure, and can include a double bond, an aromatic ring, and / or an ether bond); amides (such as dimethylformamide); dioxolanes (such as 1,3-dioxolane or 1.4-dioxolane); and / or sulfolanes.

[0080] The non-aqueous organic solvent can be used alone or in a mixture of two or more substances.

[0081] In some embodiments, if (e.g., when) a carbonate-based solvent is used, a cyclic carbonate and a chain carbonate can be mixed and used, and the cyclic carbonate and the chain carbonate can be mixed in a volume ratio of about 1:1 to about 1:9.

[0082] The lithium salt can be a material dissolved in the non-aqueous organic solvent to be used as a supply source of lithium ions in the battery, and functions in ensuring the basic operation of the rechargeable lithium battery and facilitating the movement of lithium ions between the positive electrode and the negative electrode. The lithium salt can include, for example, 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 F2y+1 SO2)(wherein x and y are integers of 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBOP), and lithium bis(oxalato)borate (LiBOB).

[0083] Rechargeable lithium battery

[0084] Based on the shape of the rechargeable lithium battery, the rechargeable lithium battery can be classified into a cylindrical type, a prismatic type, a pouch type, and a coin type (kind). Figures 2-5 A simplified diagram illustrating a rechargeable lithium battery according to one or more embodiments is illustrated, Figure 2 A cylindrical battery is illustrated, Figure 3 A prismatic battery is illustrated, and Figure 4 And Figure 5 A pouch type (kind) battery is illustrated. Referring to Figures 2-5 The rechargeable lithium battery 100 can include an electrode assembly 40 in which a separator 30 is interposed between a positive electrode 10 and a negative electrode 20, and can further include a case 50 in which the electrode assembly 40 is accommodated. The positive electrode 10, the negative electrode 20, and the separator 30 can be impregnated in an electrolyte. The rechargeable lithium battery 100 can include a sealing member 60 that seals the case 50, as illustrated in Figure 2 In some embodiments, as illustrated in Figure 3 The rechargeable lithium battery 100 can include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22, as illustrated in Figure 4 and Figure 5 The rechargeable lithium battery 100 can include an electrode tab 70, or can include a positive electrode tab 71 and a negative electrode tab 72, which can serve as an electrical path that guides outward the electric current generated in the electrode assembly 40, as each illustrated in

[0085] The rechargeable lithium battery according to one or more embodiments of the disclosure can be applied to a car, a mobile phone, and / or any other electrical device, but the disclosure is not limited thereto.

[0086] Positive electrode active material layer AML1

[0087] Figure 6 And Figure 7 An enlarged view illustrating a positive electrode active material layer AML1 of a rechargeable lithium battery according to one or more embodiments of the disclosure is illustrated. Referring to Figure 6 and Figure 7 As discussed herein, the positive electrode active material layer AML1 (see also Figure 1The positive electrode active material layer AML1 can include the first particles PTC1, a conductive material CDM, and a binder BND. The plurality of first particles PTC1 can constitute the positive electrode active material according to one or more embodiments of the present disclosure.

[0088] The positive electrode active material layer AML1 can further include a component capable of serving as a sacrificial positive electrode.

[0089] The amount of the first particles PTC1 in the positive electrode active material layer AML1 can be in the range of about 90 wt% to about 99 wt% with respect to (e.g., based on) 100 wt% of the positive electrode active material layer AML1. The amount of the binder BND and the conductive material CDM can be about 0.5 wt% to about 5 wt% with respect to (e.g., based on) 100 wt% of the positive electrode active material layer AML1.

[0090] The binder BND can bind the first particles PTC1 and the conductive material CDM to each other. For example, the binder BND can include at least one selected from the group consisting of polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, an oxirane-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, and nylon, but the present disclosure is not limited thereto.

[0091] The conductive material CDM can serve to improve the electrical conductivity of the positive electrode active material layer AML1. As the conductive material CDM, any conductive material that does not cause a chemical change in the positive electrode active material layer AML1 can be used without limitation. For example, the conductive material CDM can include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fibers, carbon nanofibers, and / or carbon nanotubes; metal powders or metal fibers containing one or more selected from the group consisting of copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; and / or mixtures (e.g., any appropriate mixture) thereof.

[0092] The first particles PTC1 are discussed in more detail elsewhere herein.

[0093] The first particles PTC1

[0094] The first particles PTC1 can include an olivine-type lithium compound expressed (e.g., represented) by Chemical Formula 1.

[0095] Chemical Formula 1

[0096] Li a1 Fe x1 B1 y1 PO4

[0097] In Chemical Formula 1, 0.8≤a1≤1.2, 0.950≤x1≤0.999, 0≤y1≤0.05, and B1may include or be at least one element selected from Ti, Al, Mg, Zr, V, Zn, Nb, K, Y, B, and Cu.

[0098] B1may be a dopant doped in the first particle PTC1. The first particle PTC1 according to one or more embodiments can be doped or not doped with a dopant material.

[0099] For the first particle PTC1, a Raman spectrum ratio (I D / I G ) obtained by Raman spectroscopy can be in a range of about 0.5 to about 1.5. In one or more embodiments, the Raman spectrum ratio (I D / I G ) can be in a range of about 0.6 to about 1.35 or about 0.9 to about 1.35.

[0100] The Raman spectrum can be measured using a Raman spectrometer. I G may refer to an intensity of a G-band peak appearing at a wave number (e.g., wave numbers) of about 1590 ± 10 centimeters to the power of -1 (cm -1 ), and I D may refer to an intensity of a D-band peak appearing at a wave number (e.g., wave numbers) of about 1340 ± 10 cm -1 .

[0101] The G-band peak according to one or more embodiments can indicate a peak derived from crystalline carbon, and the D-band peak according to one or more embodiments can represent a peak derived from amorphous carbon. The Raman spectrum ratio (I D / I G ) according to the present disclosure can determine the crystallinity of carbon.

[0102] The Raman spectrum ratio (I D / I G ) can have an optimal or appropriate range, and if (e.g., when) the Raman spectrum ratio (I D / I G ) falls within the disclosed range, excellent or appropriate electrode plate paste properties, high conductivity, and improved electrochemical properties can be exhibited.

[0103] If (e.g., when) the Raman spectrum ratio (I D / I G ) is relatively small, the ratio of crystalline carbon can increase, thereby causing the conductivity to improve, and if (e.g., when) the Raman spectrum ratio (I D / I G ) is relatively large, the amount of amorphous carbon can increase, thereby causing deterioration of electrode plate slurry properties and an increase in surface resistance.

[0104] According to one or more embodiments, if (e.g., when) the Raman spectrum ratio (I D / I G ) is less than about 0.5, the electrode plate slurry properties can deteriorate (a decrease in solid content (e.g., amount) and an increase in viscosity), and an increase in resistance (overvoltage caused by a decrease in ionic conductivity) can increase the amount of metal elution during life, which can result in deterioration of battery cell performance and a decrease in durability of the electrode. In contrast, if (e.g., when) the Raman spectrum ratio (I D / I G ) is greater than about 1.5, a coating of amorphous carbon on the surface of the particles can significantly increase to (e.g., in turn) cause an increase in resistance (hinder lithium ion intercalation and deintercalation), which can result in a decrease in reversible capacity (specific capacity) of the positive electrode and a decrease in durability of the electrode.

[0105] In one or more embodiments, the first particles PTC1 can include a coating on a surface thereof. The coating can cover (e.g., surround) an entirety or a portion of the surface of the first particles PTC1. The first particles PTC1 further include a coating of carbon-containing elements. For example, the coating can include elemental carbon and / or carbon-containing compounds. The coating can cause the first particles PTC1 to have improved structural stability and increased electrical conductivity.

[0106] The first particles PTC1 can further include carbon present in or derived from the coating and / or the grain boundary coating. The amount of carbon (e.g., as elemental carbon) in the first particles PTC1 can be in a range of about 1.0 wt% to about 1.9 wt%. The amount of carbon in the first particles PTC1 can be defined as a content of carbon included in the first particles PTC1 with respect to a weight of the first particles PTC1. That is, the amount of carbon included in the first particles PTC1 can be defined as a weight of the carbon element included in the first particles PTC1 / a weight of the first particles PTC1. The amount of carbon can be measured, for example, by a carbon sulfur analysis. However, the measurement method is not limited thereto.

[0107] If (e.g., when) the amount of carbon element in the first particles PTC1 is less than about 1.0 wt%, the carbon can not be uniformly distributed throughout the interior of the active material particles. If (e.g., when) carbon (as an equivalent of carbon element) is added in excess of about 1.9 wt%, a thick carbon coating can be generated on the surface of the active material particles.

[0108] Since the positive electrode active material of the present disclosure includes the first particles PTC1, powder packing density, capacity, and energy density can be increased. In one or more embodiments, the positive electrode active material can have a powder packing density (or a compressed density) of about 2.2 grams per cubic centimeter (g / cc) ~ about 2.6 g / cc, or about 2.3 g / cc ~ about 2.5 g / cc.

[0109] The first particles PTC1 can have a first average particle diameter APD1. The first average particle diameter APD1 can be set or changed according to one or more embodiments of Figure 6 or Figure 7 .

[0110] In one or more embodiments, referring back to Figure 6 , the first particles PTC1 can have a form of a single particle. In this description, the term "single particle" can mean a single particle in which there is no grain boundary. The single particle can indicate one particle, a monolithic structure, a single single structure, or a non-aggregated (e.g., non-agglomerated) particle in which particles are not aggregated (e.g., agglomerated) together but exist as independent phases according to morphology. For example, the single particle can be a single crystal. Alternatively, in one or more embodiments, the first particles PTC1 can be particles containing several crystals. The single particle can be independently separated. Alternatively, in one or more embodiments, the first particles PTC1 can have a form in which 2 ~ 100 independent particles are attached to each other.

[0111] If (for example, when) the first particles PTC1 are single particles (e.g., in a form of single particles), the first average particle diameter APD1 of the first particles PTC1 can be in a range of about 0.2 micrometers (μm) ~ about 20 μm. The minimum particle diameter or size of the primary particles of the first particles PTC1 can be in a range of about 50 nanometers (nm) ~ about 500 nm.

[0112] In one or more embodiments, the average particle diameter can be measured with a particle size analyzer. The average particle diameter (D 50 ) can mean a diameter of a particle of which cumulative volume is 50% by volume in a particle size distribution. In one or more embodiments, the minimum particle diameter or size of the primary particles can mean a diameter measured by randomly selecting about 30 primary particles from an electron microscope image of the first particles PTC1.

[0113] If (for example, when) the first particles PTC1 are single particles (e.g., in a form of single particles), since the first average particle diameter APD1 is extremely small, a large amount of a binder BND can be expected or required to adhere the first particles PTC1 to the positive electrode current collector (see Figure 1of the positive electrode active material layer AML1. For example, the amount of the binder BND can be in a range of about 3 wt% to about 5 wt% with respect to (e.g., based on) 100 wt% of the positive electrode active material layer AML1.

[0114] In one or more embodiments, referring back to Figure 7 The first particle PTC1 can have a polycrystalline form, and can include secondary particles (e.g., in the form of secondary particles) in which at least two primary particles NNP are aggregated (e.g., agglomerated). For example, a single first particle PTC1 can include a plurality of primary particles NNP aggregated (e.g., agglomerated) with each other. For example, the first particle can include an aggregate of a plurality of primary particles NNP. The first particle PTC1 can have a spherical shape, an ellipsoidal shape, or the like.

[0115] In one or more embodiments, the first particle PTC1 can further include a grain boundary coating on a surface of each of the primary particles NNP. The grain boundary coating can be present within (e.g., inside) the first particle PTC1. The grain boundary coating can be coated along interfaces between the primary particles NNP within the first particle PTC1. For example, the grain boundary coating can indicate a coating formed of a material coated on grain boundaries within (e.g., inside) the first particle PTC1. The grain boundary coating can include elemental carbon and / or a carbon-containing compound.

[0116] The inside of the first particle PTC1 can indicate an entire internal portion other than a surface of the first particle PTC1. For example, the inside of the first particle PTC1 can indicate an entire inside from a depth of about 10 nanometers (nm) from an outer surface of the first particle PTC1, or a portion from a depth of about 10 nm (from the outer surface) to a depth of about 2 micrometers (µm) (from the outer surface).

[0117] If (e.g., when) the first particle PTC1 further includes the grain boundary coating, structural stability can be enhanced, and a substantially uniform coating can be formed on a surface of the first particle PTC1. In some embodiments, if (e.g., when) the first particle PTC1 further includes the grain boundary coating, the first particle PTC1 can have excellent or appropriate electrical conductivity.

[0118] The first particle PTC1 can have a spherical shape in which the nanosized primary particles NNP are aggregated (e.g., agglomerated). If (e.g., when) the first particle PTC1 includes (e.g., is composed of) the primary particles NNP densely aggregated (e.g., agglomerated) with each other, the first particle PTC1 can exhibit the following properties. The first particle PTC1 can have a spherical or ellipsoidal shape.

[0119] If (for example, when) the first particles PTC1 have a secondary particle form (for example, the first particles PTC1 are spherically or ellipsoidal secondary particles composed of aggregates of a plurality of primary particles NNP), the first average particle diameter APD1 of the first particles PTC1 can be in the range of about 0.2 μm to about 20 μm.

[0120] In one or more embodiments, the average particle diameter can be measured with a particle size analyzer. The average particle diameter (D 50 ) can refer to the diameter of a particle whose cumulative volume is 50% by volume in a particle size distribution.

[0121] The first particles PTC1 can include a plurality of primary particles NNP aggregated (for example, agglomerated) with each other. The primary particles NNP can each have a particle size (average particle size) of about 10 nm to about 400 nm.

[0122] In one or more embodiments, the minimum particle diameter or the size of the primary particles NNP can refer to the diameter measured from about 30 primary particles NNP randomly selected from an electron microscope image of the first particles PTC1.

[0123] The first particles PTC1 can have a porosity of about 20% to about 60%. The porosity (n) can be defined as a pore volume (V p ) divided by a total volume (V t) , or The span value of the first particles PTC1 analyzed with the particle size analyzer can be in the range of about 0.5 to about 7.

[0124] For example, the "span" value can refer to a value obtained by using the calculation formula (D 90 -D 10 ) / D 50 , where D 10 , D 50 , and D 90 represent an index of particle size. As used herein, the terms "D 10 ", "D 50 ", and "D 90 " each are an average particle diameter represented by a cumulative volume of particles of about 10%, 50%, or 90% by volume in a particle size distribution, respectively.

[0125] Also, in the present disclosure, the first particles PTC1 can be defined as a single particle form or a secondary particle form. The single particle form refers to a single particle without a grain boundary or an interface. This can include a single crystal, a polycrystalline material containing several crystals, a monolithic structure, a single single structure, or a non-agglomerated particle. The first average particle diameter APD1 of the single particle can be in a range of about 0.2 micrometers (μm) to about 20 μm, and a minimum particle diameter can be in a range of about 50 nanometers (nm) to about 500 nm. Since it is small in size, a larger amount of a binder can be required to adhere it to a current collector. Conversely, the secondary particle form includes an agglomerated structure in which at least two primary particles NNP are combined to form a spherical or ellipsoidal shape. Such a form can have a grain boundary or an interface coating layer that enhances structural stability and electrical conductivity. The first average particle diameter APD1 of the secondary particle can also be in a range of about 0.2 μm to about 20 μm, and the primary particles NNP have a size of about 10 nm to about 400 nm. The secondary particle can have a porosity of about 20% to about 60%, and a specific surface area of about 0.1 m2 / g to about 10 m2 / g using Formula (D 90 -D 10 ) / D 50 The span value is calculated to be in a range of about 0.5 to about 7. In summary, the first particles PTC1 can be in a single particle form, characterized by its non-agglomerated structure and small size, or can be in a secondary particle form, characterized by an agglomerate of primary particles NNP and the presence of a grain boundary or an interface coating layer.

[0126] Manufacture of positive electrode active material

[0127] Figure 8 A flowchart illustrating a method of manufacturing a positive electrode active material according to one or more embodiments of the present disclosure is shown. Referring to Figure 8 The method of manufacturing the first particles PTC1 according to one or more embodiments of the present disclosure will be described in greater detail below.

[0128] An iron phosphate precursor, a lithium source, and a carbon source can be added to a solvent and mixed, thereby forming a first mixture (S100). For example, the solvent can be water and / or ethanol. The iron phosphate precursor can be a compound containing all of iron (Fe) and phosphorus (P) and / or a mixture (e.g., any suitable mixture) of a compound containing iron (Fe) and a compound containing phosphorus (P). For example, the iron phosphate precursor can include a mixture (e.g., any suitable mixture) of FePO4·H2O and / or FeSO4 and H3PO4. For example, the iron phosphate precursor can include a mixture (e.g., any suitable mixture) of FePO4 and / or FeSO4 and H3PO4.

[0129] The lithium source can include at least one selected from the group consisting of lithium oxide, lithium hydroxide, lithium chloride, lithium nitrate, lithium nitrite, lithium formate, lithium acetate, lithium oxalate, lithium carbonate, lithium phosphate, lithium hydrogen phosphate, lithium dihydrogen phosphate, and lithium citrate.

[0130] The carbon source can include at least one selected from the group consisting of glucose, sucrose, fructose, cellulose, starch, citric acid, polyacrylic acid, polyethylene glycol, and dopamine.

[0131] The carbon source can be mixed in an amount of about 5 wt% to about 20 wt% with respect to (e.g., based on) the total weight of the mixture. If (e.g., when) the carbon source is added in a small amount less than about 5 wt%, no carbon can be uniformly distributed throughout the inside of the active material particles. If (e.g., when) the carbon source is added in excess of about 20 wt%, a thick carbon coating layer can be generated on the surface of the active material particles.

[0132] The mixture can further include a dopant source. The dopant source can include an oxide-containing dopant metal and / or a chloride-containing dopant metal. For example, the dopant source can include at least one selected from the group consisting of Ti, Al, Mg, Zr, V, Zn, Nb, K, Y, B, and Cu.

[0133] The mixture can be subjected to wet milling (S200). The wet milling can use a general wet mill capable of controlling temperature. For example, the wet milling can use at least one selected from the group consisting of a bead mill, a ball mill, a mortar mill, an apex mill, a super mill, and a basket mill. During the wet milling process, the particles in the mixture can be pulverized into a fine size.

[0134] In one or more embodiments of the disclosure, the wet milling (S200) can not be provided. For example, the wet milling (S200) of the mixture can not be provided to maximize or increase the first average particle diameter APD1 of the first particles PTC1 finally manufactured.

[0135] The solvent can be removed from the mixture to form a dried mixture (S300).

[0136] If (e.g., when) the first particles PTC1 of Formula 1 are manufactured in one or more embodiments of the disclosure, Figure 6 the formation of the dried mixture can include direct evaporation of the mixture. For example, the direct evaporation can include static drying or spray drying.

[0137] If (e.g., when) the first particles PTC1 of Formula 1 are manufactured in one or more embodiments of the disclosure, Figure 7 the formation of the dried mixture can include spray drying of the mixture. The spray drying can use a general spray dryer. For example, the spray drying can use at least one selected from the group consisting of an ultrasonic spray dryer, an air nozzle spray dryer, an ultrasonic nozzle spray dryer, a filter expansion aerosol generator, and an electrostatic spray dryer.

[0138] Particles reduced to a primary particle size by a wet milling process can agglomerate (e.g., coagulate) during a spray drying process to form secondary particles. Accordingly, during the spray drying process, the flow rate and velocity of the carrier gas, the temperature, and the residence time and internal pressure in the reactor can be adjusted to form the first particles PTC1 in the form of secondary particles having a target size.

[0139] In one or more embodiments, the mixture used (e.g., for) spray drying can have a total solids content (e.g., amount) in a range of about 20 wt% to about 40 wt%. The solids content (e.g., amount) can refer to the weight percentage of the solid material remaining after solvent evaporation (or the dried mixture) relative to (e.g., based on) the total weight of the mixture (or the spray solution). For example, the spray solution can have a solids content (e.g., amount) of about 30 wt%.

[0140] If (e.g., when) the solids content (e.g., amount) is less than about 20 wt%, the first average particle diameter APD1 of the first particles PTC1 can decrease, and the yield can decrease. If (e.g., when) the solids content (e.g., amount) is greater than about 40 wt%, the first particles PTC1 can be difficult to adjust their first average particle diameter APD1 and have a large size deviation.

[0141] At the aforementioned solids content (e.g., amount), the spray solution according to the present embodiment can have a viscosity of about 1,500 millipascal seconds (mPa·s) to about 3,500 mPa·s. For example, the spray solution can have a viscosity of about 2,000 mPa·s.

[0142] In one or more embodiments, the feed rate of the spray drying can be in a range of about 0.1 kilograms per minute (kg / min) to about 0.9 kg / min. The feed rate of the spray drying can refer to the weight of the solids content (e.g., amount) in the spray solution fed per minute. For example, if (e.g., when) a spray solution having a solids content (e.g., amount) of about 20 wt% is fed at a rate of 1 kg per minute, the feed rate can be about 0.2 kg / min. In one or more embodiments of the present disclosure, the feed rate of the spray drying can be about 0.5 kg / min.

[0143] In one or more embodiments, spray drying can be performed at a temperature of about 100 °C to about 300 °C. For example, spray drying can be performed at a temperature range of about 200 °C to about 300 °C (from greater than about 200 °C to about equal to or less than about 300 °C or from about 230 °C to about 270 °C). The spray gas (e.g., air) used in the spray drying can be introduced at a first temperature and exhausted at a second temperature. For example, the first temperature can be in a range of about 200 °C to about 250 °C. The second temperature can be in a range of 80 °C to about 150 °C.

[0144] The feed pressure of the spray solution can be in a range of about 0.2 megaPascal (MPa) to about 0.7 MPa. For example, the feed pressure of the spray solution can be about 0.5 MPa.

[0145] If (e.g., when) the feed rate, feed pressure, and temperature of the spray drying satisfy the disclosed ranges, the first particles PTC1 can have a spherical shape and a desired (e.g., target) porosity.

[0146] The spray solution of the spray drying can have a flow rate of about 30 milliliters per minute (mL / min) to about 80 mL / min. If (e.g., when) the flow rate is less than about 30 mL / min, problems such as nozzle clogging and yield reduction can occur. If (e.g., when) the flow rate is greater than about 80 mL / min, moisture can condense in the spray dryer, thus problems such as incomplete drying of the mixture can occur. The feed pressure of the spray solution can be in a range of about 0.3 MPa to about 0.7 MPa. For example, the feed pressure of the spray solution can be about 0.5 MPa.

[0147] The dried mixture can be calcined (S400) under an inert environment. The inert environment can be a nitrogen environment and / or an argon environment. The calcination process can be performed in two stages in total, and the first calcination process can be performed at a temperature of about 300 °C to about 600 °C. The first calcination process can be performed for about 1 hour to about 10 hours or about 2 hours to about 6 hours. Subsequently, the second calcination process can be performed at a temperature of about 600 °C to about 800 °C. The second calcination process can be performed for about 4 hours to about 24 hours or about 6 hours to about 20 hours. The calcination of the dried mixture can form the first particles PTC1 including the compound expressed (e.g., represented) by Chemical Formula 1. If (e.g., when) the second calcination process temperature is less than about 600 °C, the low reaction temperature can cause formation of phases other than a complete olivine phase, and in some embodiments, the carbon coated on the surface of the particles can not crystallize, but rather remain primarily in the form of amorphous carbon. If (e.g., when) the second calcination process temperature is greater than about 800 °C, the carbon coated on the surface of the particles can become excessively (or substantially) crystallized to form a thick carbon coating, and this can hinder the intercalation and deintercalation of lithium ions, inducing deterioration of electrochemical performance. Further, the particle size can increase, causing an increase in resistance.

[0148] A dry pulverization process (S500) can be performed on the calcined first particles PTC1. The calcined mixture can be pulverized using an air jet mill.

[0149] If (e.g., when) the first particles PTC1 of Figure 6 are manufactured in one or more embodiments of the present disclosure, the calcined mixture can be pulverized at a rotational speed equal to or greater than about 7,000 revolutions per minute (rpm). For example, the calcined mixture can be pulverized at a rotational speed of about 7,000 rpm to about 10,000 rpm or about 7,500 rpm to about 9,000 rpm. Accordingly, the first particles PTC1 can have a secondary particle form as shown in Figure 6 .

[0150] If (e.g., when) the first particles PTC1 of Figure 7 are manufactured in one or more embodiments of the present disclosure, the calcined mixture can be pulverized at a rotational speed of about 0 rpm to about 7,000 rpm. For example, the calcined mixture can be pulverized at a rotational speed of about 4,000 rpm to about 7,000 rpm, about 4,000 rpm to about 6,000 rpm, or about 4,500 rpm to about 5,000 rpm. Unlike the manufacture of the positive electrode active material of Figure 6 , the post-calcination pulverization step (e.g., action or task) (S500) can be performed under relatively mild conditions. If (e.g., when) the first particles PTC1 of Figure 7The positive electrode active material (when), for example, dry pulverization (S500) can not be provided. If (for example, when) the rotation speed of the pulverization step (for example, action or task) (S500) satisfies the disclosed range, the first particles PTC1 can be maintained to have a secondary particle form. Accordingly, the first particles PTC1 can have a secondary particle form as shown in FIG. Figure 7 .

[0151] The primary particles manufactured can include a compound expressed (for example, represented) by Chemical Formula 1.

[0152] In a Raman spectrum obtained from Raman spectroscopy, the ratio (I -1 / I D ) of the intensity (I -1 ) of a D band peak present at a wave number (for example, wave number) of about 1340 ± 10 cm G and the intensity (I D ) of a G band peak present at a wave number (for example, wave number) of about 1590 ± 10 cm G may be in the range of about 0.5 to about 1.5,

[0153] Chemical Formula 1

[0154] Li a1 Fe x1 B1 y1 PO4

[0155] In Chemical Formula 1, 0.8 ≤ a1 ≤ 1.2, 0.950 ≤ x1 ≤ 0.999, 0 ≤ y1 ≤ 0.05, and B1 can be at least one element selected from Ti, Al, Mg, Zr, V, Zn, Nb, K, Y, B, and Cu.

[0156] In the method of manufacturing the first particles PTC1 according to one or more embodiments of the disclosure, a carbon source can be introduced into the iron phosphate precursor to uniformly (for example, substantially uniformly) form a carbon coating layer on the surface of the primary particles. Thereafter, the primary particles can be tightly agglomerated (for example, agglomerated) by spray drying to form dense secondary spherical particles. Accordingly, the first particles PTC1 can include a stable carbon coating layer on the outside and the inside of the first particles PTC1, and thus can have a relatively large amount of carbon. Figure 7 The appropriate or suitable amount of carbon of the first particles PTC1 can improve the electrical conductivity of the positive electrode active material layer AML1.

[0157] The method of manufacturing a positive electrode active material according to one or more embodiments of the disclosure can include filtering and removing iron after dry pulverization. The first particles PTC1 having a desired (for example, target) size can be obtained by filtering and removing iron.

[0158] Carbon element analysis according to one or more embodiments of the present disclosure can be performed using an elemental analyzer (for example, Elementar Micro Cube, commercially available from Elementar Analysensysteme GmbH). Detailed operating methods and conditions can be as follows. 1 mg to 2 mg of a sample can be weighed in a tin cup, and the sample can be placed in an automatic sampling tray and fed into a combustion tube through a ball valve and combusted at a combustion temperature of 1,000℃. Thereafter, a reducing copper can be used to reduce the combustion gas to form carbon dioxide. A TCD detector can be used to detect the carbon dioxide.

[0159] In the method of measuring the amount of carbon according to one or more embodiments of the present disclosure, scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) can be performed on the surface of the particles, and quantitative analysis can be performed to obtain the amount of carbon. In addition to SEM-EDS, inductively coupled plasma mass spectrometry (ICP-MS) or inductively coupled plasma optical emission spectroscopy (ICP-OES) can also be used to measure the amount of carbon.

[0160] Terms such as "substantially," "about," and "approximately" are utilized as relative terms to express the imprecise nature of a measurement or calculation by a person of ordinary skill in the art. They can include the recited value and a range of acceptable deviations from the recited value that would be determined by a person of ordinary skill in the art taking into account limitations and errors associated with the measurement of quantities. For example, "about" can refer to one or more standard deviations of the recited value, or ±30%, ±20%, ±10%, or ±5% of the recited value.

[0161] Numerical ranges recited herein are inclusive and are intended to include all sub-ranges of the same numerical value, having the same endpoints in between, as if recited. For example, a range of "1.0 to 10.0" is intended to include all sub-ranges, such as, for example, 2.4 to 7.6, between and including the minimum and maximum values, as if recited individually. Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range including the integers within the range.

[0162] Example embodiments of the present disclosure will be described below. However, the following example embodiments are only one or more possible examples, and the present disclosure is not limited to the following example embodiments disclosed herein.

[0163] Embodiments

[0164] Example Embodiment 1: Manufacture of Positive Electrode Active Material in the Form of Single Particles

[0165] FePO4-H2O as an iron phosphate precursor and lithium carbonate were mixed in a molar ratio of Fe and Li of 1 : 1.03. 8 wt% of glucose was further added to the mixture (e.g., total weight of the mixture). The mixture was subjected to a wet milling process using a ball mill. The mixture was evaporated and dried on a heated pan and then introduced into a vacuum oven at 85°C and dried for 4 hours. The dried mixture was subjected to a first calcination at 450°C under nitrogen atmosphere for 4 hours and then a second calcination at 700°C for 12 hours. The calcined product was pulverized at a rotation speed of 8,000 rpm to obtain a positive electrode active material in a single particle form.

[0166] Example Implementation 2: Manufacturing of a positive electrode active material in a secondary particle form

[0167] FePO4-H2O as an iron phosphate precursor and lithium carbonate were mixed in a molar ratio of Fe and Li of 1 : 1.03. 8 wt% of glucose was further added to the mixture (e.g., total weight of the mixture). The mixture was subjected to a wet milling process using a ball mill. The mixture was evaporated and dried on a heated pan and then introduced into a vacuum oven at 85°C and dried for 4 hours. The dried mixture was subjected to a first calcination at 450°C under nitrogen atmosphere for 4 hours and then a second calcination at 700°C for 12 hours. The calcined product was pulverized at a rotation speed of 8,000 rpm to obtain a positive electrode active material in a single particle form.

[0168] In other words, Example Implementation 1 describes the manufacturing of a positive electrode active material in a single particle form. FePO4-H2O and lithium carbonate were mixed in a molar ratio of Fe and Li of 1 : 1.03, with 8 wt% glucose added. The mixture was wet-milled with a ball mill, dried, subjected to a first calcination at 450°C under nitrogen atmosphere for 4 hours and then a second calcination at 700°C for 12 hours. The calcined product was then pulverized at 8,000 rpm.

[0169] Example Implementation 2 outlines the manufacturing of a positive electrode active material in a secondary particle form. FePO4-H2O and lithium carbonate were mixed in a molar ratio of Fe and Li of 1 : 1.03, with 12 wt% glucose added. The slurry mixture was spray-dried at 230°C under a feed pressure of 0.5 MP. The dried mixture was then calcined under the same conditions as Example Implementation 1 to obtain a secondary particle.

[0170] Example Implementation 3

[0171] A positive electrode active material was manufactured in substantially the same manner as in Example Implementation 2, except that the second calcination was performed at 780°C.

[0172] Example Implementation 4

[0173] A positive electrode active material was manufactured in substantially the same manner as in Example 1, except that 5 wt% of glucose was added to the mixture.

[0174] Example 5

[0175] A positive electrode active material was manufactured in substantially the same manner as in Example 2, except that 20 wt% of glucose was added to the mixture.

[0176] Example 6

[0177] A positive electrode active material was manufactured in substantially the same manner as in Example 2, except that 3 wt% of glucose was added to the mixture.

[0178] Example 7

[0179] A positive electrode active material was manufactured in substantially the same manner as in Example 2, except that 25 wt% of glucose was added to the mixture.

[0180] Comparative Example 1

[0181] A positive electrode active material was manufactured in substantially the same manner as in Example 2, except that the second calcination was performed at 600°C.

[0182] Comparative Example 2

[0183] A positive electrode active material was manufactured in substantially the same manner as in Example 2, except that the second calcination was performed at 800°C.

[0184] Manufacture of a positive electrode

[0185] A positive electrode active material slurry was prepared by mixing 95 wt% of the final positive electrode active material, 3 wt% of polyvinylidene fluoride as a binder, and 2 wt% of carbon black as a conductive material in an N-methylpyrrolidone solvent. The positive electrode active material slurry was coated on an aluminum current collector and dried, and then pressed to manufacture a positive electrode.

[0186] Manufacture of a rechargeable lithium battery

[0187] A 2032-type coin half-battery was manufactured using the manufactured positive electrode and a lithium metal counter electrode. A separator (having a thickness of about 16 micrometers (pm)) formed of a porous polyethylene (PE) film was arranged (e.g., inserted) between the positive electrode and the lithium metal counter electrode, and an electrolyte was introduced to manufacture a rechargeable lithium battery. 1.3M LiPF6 was mixed with a solvent including ethylene carbonate (EC), methyl ethyl carbonate (MEC), and dimethyl carbonate (DMC) mixed at a volume ratio of 3:4:3, and the mixture was used as an electrolyte.

[0188] Evaluation 1: Carbon amount in active material

[0189] Table 1 lists the results of the measured carbon amount in the example embodiments and the comparative examples.

[0190] Table 1

[0191]

[0192]

[0193] Referring to Table 1, it can be determined that the positive electrode active material according to Example Embodiment 1 through Example Embodiment 7 of the present disclosure has a carbon amount of about 1.0 wt% to about 1.9 wt% based on the total amount of the positive electrode active material.

[0194] Evaluation 2: Analysis of surface of positive electrode active material

[0195] The surface of the positive electrode active material was observed using a scanning electron microscope (SEM). Figure 9A An SEM image of the positive electrode active material manufactured in Example Embodiment 1 is shown. Figure 9B An SEM image of the positive electrode active material manufactured in Example Embodiment 2 is shown. Referring to Figure 9A It can be observed that the positive electrode active material according to Example Embodiment 1 of the present disclosure has a single particle form (e.g., a plurality of single particles), and the primary particles in the single particle form include a size of about 100 nanometers (nm) to about 600 nm (e.g., about 300 nm to about 400 nm).

[0196] Referring to Figure 9B It can be observed that the positive electrode active material according to Example Embodiment 2 of the present disclosure includes first particles in a spherical secondary particle form in which a plurality of primary particles are aggregated (e.g., agglomerated). It can be determined that the positive electrode active material in the secondary particle form has an average particle diameter of about 6 µm to about 12 µm (e.g., about 9 µm), and the primary particles (e.g., constituting) the secondary particles have a size of about 50 nm to about 200 nm.

[0197] Evaluation 3: Coating uniformity of positive electrode active material

[0198] The distribution of the coating in the positive electrode active material was observed using a transmission electron microscope (TEM). Figure 10A A TEM image of the positive electrode active material manufactured in Example Embodiment 1 is shown. Figure 10B A TEM image of the positive electrode active material manufactured in Comparative Example 1 is shown. Figure 10C A TEM image of the positive electrode active material manufactured in Example Embodiment 2 is shown.

[0199] Referring toFigure 10A and Figure 10C It can be determined that the carbon coating is uniformly (e.g., substantially uniformly) distributed on the surface and inside of the particles of the positive electrode active material according to the example embodiments of the present disclosure.

[0200] Referring to Figure 10B It can be determined that the positive electrode active material of Comparative Example 1 according to the present disclosure has an excess (or large amount) of carbon as (e.g., to generate) a thick carbon coating on the surface of the particles. Such a carbon coating can increase the specific surface area of the positive electrode active material particles, which can hinder the migration of lithium (e.g., due to an increase in electrical resistance).

[0201] Evaluation 4: Raman Spectroscopy Analysis

[0202] Raman spectroscopy analysis was performed on the positive electrode active materials manufactured in the example embodiments and the comparative example. The Raman spectroscopy analysis measured the Raman spectrum of the positive electrode active materials using LabRam HR evolution UV-VIS-NIR, which is commercially available from Horiba Ltd.

[0203] The results are shown in Table 2 and Figure 11 .

[0204] Table 2

[0205]

[0206]

[0207] Referring to Figure 11 The Raman spectrum obtained from the Raman spectroscopy analysis shows the value of the G band (1594 cm -1 ) and the value of the D band (1338 cm -1 ).

[0208] Referring to Table 2, it can be determined that the positive electrode active material according to the example embodiments of the present disclosure has a Raman spectrum ratio (I D / I G ) in the range of about 0.6 to about 1.35 obtained from the Raman spectroscopy analysis.

[0209] Evaluation 5: Battery Characteristics

[0210] The characteristics of the rechargeable lithium battery manufactured using the positive electrode active materials of the example embodiments and the comparative example were evaluated.

[0211] The rechargeable lithium battery was initially charged under conditions of constant current (0.2C) and constant voltage (3.80V, cut-off about 0.05C), and after resting for 10 minutes, was initially discharged under conditions of constant current (0.2C) until the voltage reached 2.5V, thereby obtaining an initial charge capacity (3.80V charge capacity) and an initial discharge capacity (2.50V discharge capacity), and an efficiency (2.5V~3.8V efficiency) expressed as the initial discharge capacity / initial charge capacity. Thereafter, the rechargeable lithium battery was charged and discharged once at a rate of 0.2C (about 3.80V, cut-off about 0.05C) / 0.2C (about 2.50V, cut-off about 0.05C) at -20℃, thereby obtaining an initial discharge capacity at -20℃ (-20℃ capacity). The results of the evaluation of the battery characteristics are shown in Table 3.

[0212] Table 3

[0213]

[0214] Referring to Table 3, it can be observed that the rechargeable lithium battery according to the example embodiments of the present disclosure has a greater capacity than the rechargeable lithium battery according to the comparative example. It can also be observed that the rechargeable lithium battery according to the example embodiments of the present disclosure exhibits more excellent charging and / or discharging efficiency than the rechargeable lithium battery according to the comparative example. In some embodiments, it can be observed that the rechargeable lithium battery according to the example embodiments of the present disclosure has a more superior or more appropriate low-rate capacity value than the rechargeable lithium battery according to the comparative example.

[0215] Accordingly, it can be determined that each of the positive electrode active materials according to the example embodiments has a positive electrode active material having a carbon content (e.g., amount) in the range of about 1.0wt%~1.9wt% (e.g., satisfying), and a Raman spectrum ratio (I D / I G ) of about 0.6~1.35 obtained from Raman spectrum analysis. The positive electrode active material according to the example embodiments includes carbon having an optimal or appropriate amount and thickness uniformly distributed to significantly improve the electrical conductivity and electrochemical properties of the rechargeable lithium battery.

[0216] The positive electrode active material according to the present disclosure can include a first particle.

[0217] In the positive electrode active material according to the present disclosure, the first particle can be uniformly (e.g., substantially uniformly) coated with an optimal or appropriate amount of a coating material. The rechargeable lithium battery according to the present disclosure can have high electrical conductivity and improved electrochemical properties.

[0218] The battery manufacturing apparatus, battery management system (BMS) apparatus, and / or any other related apparatus or components according to embodiments of the present disclosure described herein can be implemented with any suitable hardware, firmware (e.g., application specific integrated circuits), software, or a combination of software, firmware, and hardware. For example, components of the apparatus can be formed on one integrated circuit (IC) chip or on separate IC chips. Further, the components can be implemented on a flexible printed circuit film, a tape carrier package (TCP), or a printed circuit board (PCB), or formed on one substrate. Further, the components of the apparatus can be one or more processors in one or more computing devices running computer program instructions and interacting with other system components to perform the processes or threads described herein. The computer program instructions can be stored in a memory that 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. Also, a person of ordinary skill in the art should recognize that the functionality of the computing device can be combined or integrated into a single computing device, or the functionality of a dedicated computing device can be distributed across one or more other computing devices, without departing from the scope of the present disclosure.

[0219] In view of the entire disclosure, those skilled in the art will recognize that each appropriate feature of the embodiments of the present disclosure can be combined in part or in whole with each other, and can be technically interlocked and operated in one or more appropriate manners, and each embodiment can be implemented independently of each other or in any appropriate manner in combination with each other, unless otherwise stated or implied.

[0220] While the present disclosure has been described in connection with the example embodiments described herein, it will be understood that the present disclosure is not limited to the disclosed example embodiments, and is intended to cover any appropriate modifications and equivalent arrangements included within the spirit and scope of the claims and their equivalents. Accordingly, the foregoing example embodiments are to be considered in all respects as illustrative only, and not restrictive, of the present disclosure.

Claims

1. A positive electrode active material comprising first particles, the first particles comprising a compound represented by Chemical Formula 1, and having a first average particle diameter, wherein a Raman spectrum of the first particles comprises: D band peak at a wave number of 1340 ± 10 cm -1 D band peak at a wave number of 1340 ± 10 cm a G-band peak at a wave number of 1590 ± 10 cm -1 and a G-band peak at a wave number of 1590 ± 10 cm the intensity I of the D band peak D the ratio I G of the intensity I D of the D band peak to the intensity I G is 0.5 to 1.5, Chemical Formula 1 Li a1 Fe x1 B1 y1 PO4, wherein, in Chemical Formula 1, 0.8≤a1≤1.2， 0.950≤x1≤0.999， 0 ≤ y1 ≤ 0.05, and B1 is at least one element selected from the group consisting of Ti, Al, Mg, Zr, V, Zn, Nb, K, Y, B, and Cu. 2.The positive electrode active material of claim 1, wherein the first particles further comprise a coating layer containing a carbon element. 3.The positive electrode active material of claim 1, wherein the first particles further comprise a coating layer containing a carbon element, and an amount of the carbon element in the first particles is 1.0 wt% to 1.9 wt%. 4.The positive electrode active material of claim 1, wherein the first particles are single particles, and the first average particle diameter is 0.2 μm to 20 μm. 5.The positive electrode active material of claim 4, wherein the first particles comprise at least one primary particle, and a size of the primary particle is 50 nm to 500 nm. 6.The positive electrode active material of claim 1, wherein the first particles comprise an aggregate of a plurality of primary particles, and an average particle size of the primary particles is 10 nm to 400 nm. 7.The positive electrode active material of claim 6, wherein the first particles are spherical secondary particles, and the first average particle diameter is 0.2 μm to 20 μm. 8.The positive electrode active material of claim 6, wherein the first particles further comprise a grain boundary coating layer on an interface between the primary particles, and wherein the grain boundary coating layer comprises a carbon element. 9.The positive electrode active material of claim 6, wherein a porosity of the first particles is 20% to 60%. 10.The positive electrode active material of claim 5, wherein a span value of the first particles analyzed with a particle size analyzer is 0.5 to 7. 11.A method of manufacturing a positive electrode active material, comprising: forming a mixture by mixing an iron phosphate precursor, a lithium source, and a carbon source; drying the mixture; and preparing first particles by calcining the dried mixture, wherein the first particles comprise a compound represented by Chemical Formula 1, wherein a Raman spectrum of the first particles comprises: D band peak at a wave number of 1340 ± 10 cm -1 D band peak at a wave number of 1340 ± 10 cm a G-band peak at a wave number of 1590 ± 10 cm -1 and a G-band peak at a wave number of 1590 ± 10 cm the intensity I of the D band peak D the ratio I of the intensity of the D band peak G D / I G is 0.5 to 1.5,​ Chemical Formula 1 Li a1 Fe x1 B1 y1 PO4, wherein, in Chemical Formula 1, 0.8≤a1≤1.2， 0.950≤x1≤0.999， 0 ≤ y1 ≤ 0.05, and B1 is at least one element selected from the group consisting of Ti, Al, Mg, Zr, V, Zn, Nb, K, Y, B, and Cu. 12.The method of claim 11, wherein the forming of the mixture comprises adding a dopant source and performing a mixing process. 13.The method of claim 11, wherein the carbon source is mixed in an amount of 5 wt% to 20 wt% based on a total weight of the mixture. 14.The method of claim 11, wherein the drying of the mixture comprises spray drying.

15. The method of claim 14, wherein the mixture is a spray solution having a solid amount of 20 wt% to 40 wt% and a viscosity of 1,500 mPa-s to 2,500 mPa-s.

16. The method of claim 14, wherein the spray drying of the mixture is performed to produce secondary particles composed of aggregated primary particles.

17. The method of claim 14, wherein the spray drying is performed at a temperature of 100 °C to 300 °C.

18. The method of claim 14, wherein a spray solution used for the spray drying has a feed pressure of 0.3 MPa to 0.7 MPa and a flow rate of 30 mL / min to 80 mL / min.

19. The method of claim 11, wherein the calcination is performed once or twice and at a temperature of 300 °C to 800 °C.

20. A rechargeable lithium battery comprising the positive electrode active material according to any one of claims 1 to 10 or manufactured by the method of manufacturing a positive electrode active material according to any one of claims 11 to 19.

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