Positive electrode active material layer, rechargeable lithium battery, and method of manufacturing rechargeable lithium battery

Abstract

Disclosed are a positive electrode active material layer, a rechargeable lithium battery, and a method of manufacturing the rechargeable lithium battery. The positive electrode active material layer comprises a positive electrode active material, a sacrificial positive electrode material, a functional additive, a conductive material and a binder. The functional additive comprises an azole compound. An amount of the functional additive is in a range of about 0.03 parts by weight to about 0.3 parts by weight with respect to 100 parts by weight of the positive electrode active material layer.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2024-0104624, filed on August 6, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to an additive for the positive electrode of a rechargeable lithium battery. Background Technology

[0003] With the increasing prevalence of battery-powered electronic devices (such as mobile phones, laptops, and electric vehicles), the demand for rechargeable batteries with high energy density and high capacity is growing. Therefore, improving the performance of rechargeable lithium batteries would be beneficial.

[0004] A rechargeable lithium battery typically includes a positive electrode, a negative electrode, and an electrolyte. The positive and negative electrodes contain active materials that can be inserted and extracted. When lithium ions are inserted and extracted, the rechargeable lithium battery generates electrical energy from oxidation and reduction reactions. Summary of the Invention

[0005] Example embodiments of this disclosure include a positive electrode comprising a functional additive.

[0006] Example embodiments of this disclosure include a method for manufacturing a rechargeable lithium battery, in which functional additives are added to manufacture the rechargeable lithium battery.

[0007] According to exemplary embodiments of this disclosure, the positive electrode active material layer may include a positive electrode active material, a sacrificial positive electrode material, a functional additive, a conductive material, and a binder. The functional additive may include azole compounds. The amount of the functional additive relative to 100 parts by weight of the positive electrode active material layer may range from about 0.03 parts by weight to about 0.3 parts by weight.

[0008] According to an example embodiment of this disclosure, a rechargeable lithium battery may include a positive electrode, a negative electrode, and an electrolyte layer between the positive and negative electrodes. The positive electrode may include a positive electrode current collector and a layer of positive electrode active material on the positive electrode current collector. The positive electrode active material layer may include a positive electrode active material, a sacrificial positive electrode material, a functional additive, a conductive material, and a binder. The functional additive may include azole compounds. The functional additive, the positive electrode active material, and the sacrificial positive electrode material may be present in a first amount, a second amount, and a third amount, respectively, relative to the positive electrode active material layer. The value of Formula 1 may range from about 0.5 to about 2.

[0009] Formula 1:

[0010] According to an example embodiment of this disclosure, a method for manufacturing a rechargeable lithium battery may include the following steps: mixing a positive electrode active material, a sacrificial positive electrode material, a conductive material, a binder, and a functional additive to prepare a positive electrode active material slurry; and coating the positive electrode active material slurry onto a current collector to form a positive electrode active material layer. The amount of the functional additive relative to 100 parts by weight of the positive electrode active material can range from about 0.03 parts by weight to about 0.3 parts by weight. The amount of the sacrificial positive electrode material relative to 100 parts by weight of the positive electrode active material slurry can range from about 1 part by weight to about 15 parts by weight. Attached Figure Description

[0011] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure is shown.

[0012] Figures 2 to 5 A simplified diagram illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure is shown.

[0013] Figure 6 A cross-sectional view is shown illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure.

[0014] Figure 7 It shows Figure 6 A magnified view of part M.

[0015] Figure 8 This is a flowchart illustrating a method for manufacturing a rechargeable lithium battery according to an example embodiment. Detailed Implementation

[0016] To provide a full understanding of the structure and effects of this disclosure, some exemplary embodiments of the disclosure have been described with reference to the accompanying drawings. However, it should be noted that this disclosure is not limited to the following exemplary embodiments and can be implemented in various forms. Rather, the exemplary embodiments are provided merely to disclose this disclosure and to allow those skilled in the art to fully understand its scope.

[0017] In this specification, it is understood that when an element is referred to as being "on" another element, the element may be "directly on" the other element, or an intervening element may be present therein. In the accompanying drawings, the thickness of some components may be exaggerated for the purpose of effectively explaining the technical content. Throughout the specification, the same reference numerals refer to the same elements.

[0018] Unless otherwise stated in this specification, singular expressions may include plural expressions. Additionally, unless otherwise specified, the phrase "A or B" may mean "A but not B," "B but not A," and "A and B." The terms "comprising / including" and / or variations thereof included in this disclosure do not exclude the presence or addition of one or more other components.

[0019] As included herein, the term "combination of them" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, or reaction products.

[0020] Unless otherwise specifically defined in this specification, particle size may be the average particle size. Additionally, particle size refers to the average particle size (Dsize) that represents approximately 50% of the cumulative volume in the particle size distribution. 50 Average particle size (D) 50 The particle size can be measured using methods known to those skilled in the art (e.g., by a particle size analyzer, transmission electron microscopy (TEM) images, or scanning electron microscopy (SEM) images). Optionally, a dynamic light scattering measurement device is included to perform data analysis, count the number of particles for each particle size range, and calculate the average particle size (D) from the number of counted particles. 50 The laser scattering method can also be used to measure the average particle size (D). 50 In the laser scattering method, target particles are distributed in a dispersion solvent and introduced into a laser scattering particle measuring device (e.g., the MT3000, commercially available from Microtrac Ltd.). The particles are irradiated with ultrasound at 28 kHz at a power of 60 W, and the average particle size (D) is calculated in the measuring device using a 50% standard of particle size distribution. 50 ).

[0021] When the terms “about” or “substantially” are used in conjunction with numerical values ​​in this specification, it is intended that the relevant numerical values ​​include a tolerance of ±10% around the stated value. When a range is specified, the range includes all values ​​within that range, such as increments of 0.1%.

[0022] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure is shown. (Refer to...) Figure 1 The rechargeable lithium battery 100 may include a positive electrode 10, a negative electrode 20, a separator 30, and an electrolyte solution ELL.

[0023] The positive electrode 10 and the negative electrode 20 can be separated from each other by a diaphragm 30. The diaphragm 30 can be located between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20 and the diaphragm 30 can be in contact with the electrolyte solution ELL. The positive electrode 10, the negative electrode 20 and the diaphragm 30 can be immersed in the electrolyte solution ELL.

[0024] The electrolyte solution ELL can be or includes a medium through which lithium ions are transferred between the positive electrode 10 and the negative electrode 20. In the electrolyte solution ELL, lithium ions can move toward one of the positive electrode 10 and the negative electrode 20 through the membrane 30.

[0025] In the case of rechargeable batteries that include gel polymer electrolytes (or semi-solid electrolytes) and solid electrolytes, an electrolyte layer may be included. In this case, the electrolyte layer can replace the function of the separator 30 and the electrolyte solution ELL.

[0026] Positive electrode 10 The positive electrode 10 for a rechargeable lithium battery may include a current collector COL1 and a positive electrode active material layer AML1 formed on the current collector COL1. The positive electrode active material layer AML1 may include a positive electrode active material and also includes a binder and / or a conductive material. The amount of positive electrode active material in the positive electrode active material layer AML1 may range from about 90 wt% to about 99.5 wt% relative to 100 wt% of the positive electrode active material layer AML1. The amount of each or at least one of the binder and conductive material may range from about 0.5 wt% to about 5 wt% relative to 100 wt% of the positive electrode active material layer AML1. The positive electrode active material layer AML1 may also include sacrificial positive electrode material and functional additives. The positive electrode according to some example embodiments of the present disclosure is discussed in further detail below. Aluminum (Al) may be included as the current collector COL1, but the present disclosure is not limited thereto.

[0027] Positive electrode active material The positive electrode active material in the positive electrode active material layer AML1 may include compounds capable of reversibly inserting and deintercalating lithium (e.g., lithiation intercalation compounds). For example, the positive electrode active material may include at least one composite oxide comprising lithium and a metal, wherein the metal is or includes at least one of cobalt, manganese, nickel, and combinations thereof.

[0028] Composite oxides may include lithium transition metal composite oxides, such as lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free lithium nickel manganese oxides, and combinations thereof, at least one of these.

[0029] For example, the positive electrode active material may include a compound represented by one of the following chemical formulas: Lia A 1- b X b O 2-c D c (Where, 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 (Where, 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 (Where, 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 (Where, 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 (where 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 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a CoG b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn 1-b G b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn 1-g G g PO4 (where 0.90 ≤ a ≤ 1.8 and 0 ≤ g ≤ 0.5); Li (3-f) Fe2(PO4)3 (where 0≤f≤2); Li aFePO4 (where 0.90≤a≤1.8).

[0030] In the above chemical formulas, A is or includes at least one of Ni, Co, Mn, and combinations thereof; X is or includes at least one of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and combinations thereof; D is or includes at least one of O, F, S, P, and combinations thereof; G is or includes at least one of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; and L 1 It is or includes at least one of Mn, Al and combinations thereof.

[0031] For example, the positive electrode active material can be or includes a high-nickel positive electrode active material having a nickel content of equal to or greater than about 80 mol%, equal to or greater than about 85 mol%, equal to or greater than about 90 mol%, equal to or greater than about 91 mol%, or equal to or greater than about 94 mol% and equal to or less than about 99 mol% relative to 100 mol% of lithium-free metal in the lithium transition metal complex oxide. High-nickel positive electrode active materials can achieve high capacity and are therefore applicable to high-capacity and high-density rechargeable lithium batteries.

[0032] The positive electrode active material may be present in an amount ranging from about 85 parts by weight to about 98 parts by weight relative to 100 parts by weight of the positive electrode active material layer AML1. The positive electrode active material may include residual lithium on its surface. The residual lithium on the surface of the positive electrode active material may be or include lithium (Li) particles or lithium (Li)-containing compounds. For example, lithium (Li)-containing compounds may be or include at least one of LiOH and Li₂CO₃, but this disclosure is not limited thereto. The amount of residual lithium on the surface of the positive electrode active material may range from about 1 part by weight to about 4 parts by weight relative to 100 parts by weight of the sacrificial positive electrode material.

[0033] Positive electrode binder The binder can be configured to improve the adhesion between the positive electrode active material particles and to the current collector COL1. The binder may include, for example, at least one of polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylate resin, polyester resin, and nylon, but this disclosure is not limited thereto.

[0034] Positive electrode conductive material Conductive materials may be included to provide electrodes with conductivity, and any suitable conductive material that does not cause chemical changes in the battery may be included as the conductive material. Conductive materials may include, for example: carbon-based materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal powders or metal fibers, including one or more of copper, nickel, aluminum, and silver; conductive polymers, such as polyphenylene derivatives; or mixtures thereof.

[0035] negative electrode 20 The negative electrode 20 for a rechargeable lithium battery may include a current collector COL2 and a negative electrode active material layer AML2 located on the current collector COL2. The negative electrode active material layer AML2 may include a negative electrode active material, and may also include a binder and / or a conductive material.

[0036] For example, the negative electrode active material layer AML2 may include a negative electrode active material in the range of about 90 wt% to about 99 wt%, a binder in the range of about 0.5 wt% to about 5 wt%, and a conductive material in the range of about 0 wt% to about 5 wt%.

[0037] negative electrode binder The binder can be configured to improve the adhesion between the negative electrode active material particles and to the current collector COL2. The binder may include at least one of non-aqueous binders, aqueous binders, dry binders, and combinations thereof.

[0038] Non-aqueous adhesives may include at least one of polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, and combinations thereof.

[0039] Waterborne adhesives may include at least one of styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomers, polyethylene oxide, polyvinylpyrrolidone, polyepoxychloropropane, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0040] When an aqueous binder is included as the negative electrode binder, a cellulose compound capable of providing adhesion may be further included. The cellulose compound may include one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and their alkali metal salts. The alkali metal may include at least one of Na, K, and Li.

[0041] Dry adhesives may include at least one of fibrillable polymeric materials, such as polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and combinations thereof.

[0042] Negative electrode conductive material Conductive materials may be included to provide electrodes with conductivity, and any suitable conductive material that does not cause chemical changes in the battery may be included as a conductive material to constitute the battery. For example, conductive materials may include: carbon-based materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal powders or metal fibers, including one or more of copper, nickel, aluminum, and silver; conductive polymers, such as polyphenylene biopolymers; or mixtures thereof.

[0043] Negative electrode current collector The current collector COL2 may include at least one of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof.

[0044] Negative electrode active material The negative electrode active material in the negative electrode active material layer AML2 may include at least one of the following: materials capable of reversibly inserting and de-intercalating lithium ions, lithium metal, lithium metal alloys, materials capable of doping and de-doping lithium, and transition metal oxides.

[0045] Materials capable of reversibly inserting and deintercalating lithium ions can include carbon-based negative electrode active materials, such as crystalline carbon, amorphous carbon, or combinations thereof. For example, crystalline carbon can include graphite (such as amorphous, flake, sheet, spherical, or fibrous natural or artificial graphite), and amorphous carbon can include at least one of soft carbon, hard carbon, mesophase pitch carbon, and calcined coke.

[0046] Lithium metal alloys may include alloys of lithium and metals including or including at least one of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0047] Materials capable of doping and undoping lithium may include at least one of Si-based negative electrode active materials and Sn-based negative electrode active materials. The Si-based negative electrode active materials may include silicon, silicon-carbon composites, SiO x (where 0 < x ≤ 2), Si-Q alloys (where Q is or includes at least one of 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 combinations thereof), and combinations of at least one of them. The Sn-based negative electrode active materials may include at least one of Sn, SnO2, Sn-based alloys, and combinations thereof.

[0048] The silicon-carbon composite may be or include a composite of silicon and amorphous carbon. According to an exemplary embodiment, the silicon-carbon composite may have a structure in which amorphous carbon is coated on the surface of silicon particles. For example, the silicon-carbon composite may include secondary particles (cores) in which primary silicon particles are assembled and an amorphous carbon coating layer (shell) on the surface of the secondary particles. Amorphous carbon may also be located between the primary silicon particles, and for example, the primary silicon particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0049] The silicon-carbon composite may also include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles, and may also include an amorphous carbon coating layer on the surface of the core.

[0050] The Si-based negative electrode active material or the Sn-based negative electrode active material may be included in combination with a carbon-based negative electrode active material.

[0051] Separator 30 Based on the type of rechargeable lithium battery, the separator 30 may be located between the positive electrode 10 and the negative electrode 20. The separator 30 may include one or more of polyethylene, polypropylene, and polyvinylidene fluoride, and may have a multilayer separator such as a polyethylene / polypropylene bilayer separator, a polyethylene / polypropylene / polyethylene trilayer separator, and a polypropylene / polyethylene / polypropylene trilayer separator.

[0052] The separator 30 may include a porous substrate and a coating layer on one surface or on opposite surfaces of the porous substrate, the coating layer including an organic material, an inorganic material, or a combination thereof.

[0053] The porous substrate may be or include a polymer layer comprising at least one of polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon and polytetrafluoroethylene, or may be or include copolymers or mixtures comprising two or more of the above materials.

[0054] Organic materials may include polyvinylidene fluoride copolymers or (meth)acrylic acid copolymers.

[0055] Inorganic materials may include inorganic particles, such as or including at least one of Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but this disclosure is not limited thereto.

[0056] Organic and inorganic materials can be mixed in a single coating layer, or they can exist as a stack of coating layers including organic materials and coating layers including inorganic materials.

[0057] Electrolyte solution ELL Electrolyte solutions (ELLs) used in rechargeable lithium batteries may include non-aqueous organic solvents and lithium salts.

[0058] Non-aqueous organic solvents can be constructed as media for transporting ions that participate in the electrochemical reactions of a battery.

[0059] Non-aqueous organic solvents may include at least one of carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents, and combinations thereof.

[0060] Carbonate solvents may include at least one of 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 butyl carbonate (BC).

[0061] Ester solvents may include at least one of methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonate lactone, valproic acid lactone, and caprolactone.

[0062] Ether solvents may include at least one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and tetrahydrofuran. Ketone solvents may include cyclohexanone. Alcohol solvents may include at least one of ethanol and isopropanol. Aprotic solvents may include at least one of: nitriles, such as R-CN (where R is a hydrocarbon group having a C2 to C20 straight-chain, branched, or cyclic structure, and may include double bonds, aromatic rings, or ether groups); amides, such as dimethylformamide; dioxolane, such as 1,3-dioxolane or 1,4-dioxolane; or sulfolane.

[0063] Non-aqueous organic solvents may be included alone or as a mixture of two or more substances.

[0064] Additionally, when carbonate solvents are included, cyclic carbonates and chain carbonates can be mixed and included, and the cyclic carbonates and chain carbonates can be mixed in a volume ratio ranging from about 1:1 to about 1:9.

[0065] Lithium salts can be or include materials dissolved in non-aqueous organic solvents to be configured as a source of lithium ions in a battery, and which function to enable the basic operation of a rechargeable lithium battery and facilitate the movement of lithium ions between the positive and negative electrodes. Lithium salts can include, for example, 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 At least one of the following: (SO2) (where x and y are integers from 1 to 20), lithium trifluoromethane sulfonate, lithium tetrafluoroethane sulfonate, lithium difluoro(oxalate)borate (LiDFOB), lithium difluoro(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0066] Rechargeable lithium batteries Based on their shape, rechargeable lithium batteries can be classified as cylindrical, prismatic, pouch-shaped, and coin-shaped. Figures 2 to 5 This is a simplified diagram illustrating a rechargeable lithium battery according to an embodiment, and Figure 2 A cylindrical battery is shown. Figure 3 A prismatic battery is shown, and Figure 4 and Figure 5 A pouch-type battery is shown. (See reference) Figures 2 to 4The rechargeable lithium battery 100 may include an electrode assembly 40 in which a separator 30 is disposed between a positive electrode 10 and a negative electrode 20, and may also include a housing 50 in which the electrode assembly 40 is housed. The positive electrode 10, the negative electrode 20, and the separator 30 may be immersed in an electrolyte solution. Figure 2 As shown, the rechargeable lithium battery 100 may include a sealing member 60 of the sealed housing 50. Additionally, as... Figure 3 As shown, the rechargeable lithium battery 100 may include a positive electrode lead connector 11, a positive electrode terminal 12, a negative electrode lead connector 21, and a negative electrode terminal 22. Figure 4 and Figure 5 As shown, the rechargeable lithium battery 100 may include Figure 5 The electrode connector 70 shown is or Figure 4 The positive electrode terminal 71 and negative electrode terminal 72 shown are configured as electrical paths for guiding the current generated in the electrode assembly 40 to the outside of the rechargeable lithium battery 100.

[0067] The rechargeable lithium battery according to the exemplary embodiments of this disclosure can be used in, for example, motor vehicles, mobile phones and / or any other electrical devices, but this disclosure is not limited thereto.

[0068] The following description focuses on rechargeable lithium batteries and methods of manufacturing rechargeable lithium batteries according to exemplary embodiments of the present disclosure.

[0069] The rechargeable lithium battery according to exemplary embodiments of this disclosure may include a high-nickel positive electrode active material. For example, the positive electrode active material according to exemplary embodiments may include a compound represented by the following chemical formula 1.

[0070] Chemical Formula 1: Li a Ni x Co y Mn z X c O 2-b .

[0071] In chemical formula 1, 0.8≤a≤1.2, 0.8≤x≤1.0, 0≤y≤0.1, 0≤z≤0.1, 0≤c≤0.1, 0≤b≤0.05, and x+y+z+c=1, and X can be or include at least one of Al, Ti, Mg, Zr, Mo and Nb.

[0072] It can include high-nickel positive electrode active materials to increase battery capacity.

[0073] Reference Figure 6 and Figure 7The positive electrode active material layer of this disclosure is described in detail below. The positive electrode active material layer may include sacrificial positive electrode material, functional additives, and residual lithium.

[0074] Sacrificial positive electrode material The positive electrode active material layer according to an example embodiment of this disclosure may include a sacrificial positive electrode material. The sacrificial positive electrode material can improve the stability and performance of the rechargeable lithium battery.

[0075] For example, sacrificial positive electrode materials can replenish lithium to the positive electrode of a rechargeable lithium battery. Sacrificial positive electrode materials can include lithium-based materials. For example, sacrificial positive electrode materials can include lithium metal oxides. The amount of lithium ions included in the sacrificial positive electrode material can be equal to or greater than about 2 moles relative to 1 mole of the sacrificial positive electrode material. For example, sacrificial positive electrode materials can include compounds represented by the following chemical formula 2.

[0076] Chemical formula 2: Li a XO b .

[0077] In Formula 2, 2 ≤ a ≤ 10 and 2 ≤ b ≤ 5. In Formula 2, X can be or include at least one of Be, Sr, Ba, Sc, Y, Lu, Zr, Cr, Mo, W, Ru, Os, Ir, Pd, Pt, Cu, Ag, Au, Cd, Co, Ni, Mn, Fe, Al, Mg, Zn, Ti, and combinations thereof. For example, the sacrificial positive electrode material can be or include at least one of Li5FeO4, Li2NiO2, and Li6CoO4, but this disclosure is not limited thereto. The sacrificial positive electrode material can be present in an amount ranging from about 1 part by weight to about 15 parts by weight, about 1 part by weight to about 5 parts by weight, or about 1 part by weight to about 3 parts by weight relative to 100 parts by weight of the positive electrode active material layer.

[0078] The sacrificial positive electrode material may include residual lithium on its surface. The residual lithium on the surface of the sacrificial positive electrode material may be or include lithium (Li) particles or lithium (Li) compounds. The amount of residual lithium on the surface of the sacrificial positive electrode material may range from about 2 parts by weight to about 10 parts by weight relative to 100 parts by weight of the sacrificial positive electrode material.

[0079] The amount of residual lithium on the surface of the positive electrode active material can be less than the amount of residual lithium on the surface of the sacrificial positive electrode material. When the amount of residual lithium on the sacrificial positive electrode material is greater than the amount of residual lithium on the positive electrode active material, and when the amount of lithium removed from the interior of the sacrificial positive electrode material is greater than the amount of lithium removed from the interior of the positive electrode active material, the amount of residual lithium released from the sacrificial positive electrode material can be greater than the amount of residual lithium released from the positive electrode active material. The amount of residual lithium in the positive electrode active material layer can be equal to the sum of the amount of residual lithium on the surface of the positive electrode active material and the amount of residual lithium on the sacrificial positive electrode material. Relative to 100 parts by weight of the positive electrode active material layer, the residual lithium in the positive electrode active material layer can be present in an amount ranging from about 0.01 parts by weight to about 4 parts by weight (e.g., from about 0.01 parts by weight to about 1 part by weight).

[0080] When residual lithium is present in an amount greater than about 4 parts by weight relative to 100 parts by weight of the positive electrode active material layer, gelation of the positive electrode active material slurry or deterioration of the binder may occur, resulting in deterioration of the positive electrode active material.

[0081] Functional additives The positive electrode active material layer according to an example embodiment of this disclosure may include functional additives. These functional additives can improve the stability and performance of rechargeable lithium batteries.

[0082] Functional additives can reduce surface degradation caused by side reactions in the positive electrode active material. For example, functional additives can solve complex problems in batteries, such as slurry gelation, increased resistance, reduced cycle life, and increased gas generation. Therefore, rechargeable lithium batteries can achieve improvements in processability and performance.

[0083] For the layered positive electrode active materials discussed above, the recent trend in industry is to reduce the amount of cobalt (Co), which is usually expensive, and increase the amount of nickel (Ni), which exhibits high capacity.

[0084] However, an increase in the amount of nickel (Ni) in the positive electrode active material can lead to the reduction and / or reaction of nickel cations on the surface of the active material by atmospheric and / or moisture gases, potentially increasing the frequency of side reactions. Therefore, internal lithium loss and lithium compound formation can cause reversible capacity degradation and reduced processability. Furthermore, in the case of layered active materials with a large amount of nickel, performance degradation may begin at the surface of the active material. Therefore, there may be considerations to introduce coating and structural stabilization processes to protect the surface of the positive electrode active material; these methods may lead to increased costs and reduced energy density.

[0085] Functional additives may include azole compounds. Azole compounds may refer to compounds that include or contain at least one functional group such as imidazole, triazole, pyrazol, or thiazolyl.

[0086] Compounds containing an imidazole group can refer to imidazole derivatives. Optionally, compounds containing an imidazole group can be or include compounds containing two or more imidazole groups. Compounds containing a triazole group can refer to triazole derivatives. Optionally, compounds containing a triazole group can be or include compounds containing two or more triazole groups. Compounds containing a pyrazole group can refer to pyrazole derivatives. Optionally, compounds containing a pyrazole group can be or include compounds containing two or more pyrazole groups. Compounds containing a thiazole group can refer to thiazole derivatives. Optionally, compounds containing a thiazole group can be or include compounds containing two or more thiazole groups.

[0087] Imidazoles can be represented by the molecular formula C3N2H4 or as heterocyclic compounds including carbon (C) and nitrogen (N). Imidazole compounds can be or include heterocyclic compounds having non-adjacent nitrogen atoms.

[0088] Triazoles can be represented by the molecular formula C2H3N3 or as heterocyclic compounds including carbon (C) and nitrogen (N). Triazole compounds can have one or more isomers. For example, isomers of triazole compounds can be or include 1H-1,2,4-triazole, 1H-1,2,3-triazole, 2H-1,2,3-triazole, and 4H-1,2,4-triazole.

[0089] Pyrazoles can be represented by the molecular formula C3H4N2 or as heterocyclic compounds containing carbon (C) and nitrogen (N). Pyrazole compounds can refer to heterocyclic compounds characterized by a five-membered ring comprising two adjacent nitrogen atoms.

[0090] Thiazoles can be represented by the molecular formula C3H3NS or as heterocyclic compounds comprising carbon (C), sulfur (S), and nitrogen (N). Thiazole compounds can refer to heterocyclic compounds characterized by a five-membered ring comprising non-adjacent sulfur (S) and nitrogen (N) atoms.

[0091] Functional additives according to exemplary embodiments of this disclosure can be added to the positive electrode active material layer, and can achieve improved processability, stability, and battery performance. For example... Figure 7 As shown, the coating layer CTL can be disposed on the surface of at least one of the positive electrode active material AM1 and the sacrificial positive electrode material. The coating layer CTL may include functional additives. The addition of functional additives can form the coating layer CTL on the surface of each or at least one of the positive electrode active material AM1 and the sacrificial positive electrode material. The coating layer CTL can reduce or prevent the removal of residual lithium from the surface of each or at least one of the positive electrode active material AM1 and the sacrificial positive electrode material.

[0092] The positive electrode active material can be incorporating functional additives, including azole compounds, to reduce surface degradation and improve cycle life characteristics. For example, nitrogen (N) atoms in the functional additive can bind to metal ions in the positive electrode active material, thereby reducing surface degradation. Lithium loss from the positive electrode active material can be reduced or suppressed. Battery stability and performance can be improved even when the positive electrode active material layer is fabricated on a thick-film electrode plate. In example embodiments, the thickness of the positive electrode active material layer can range from about 5 μm to about 70 μm, for example, about 10 μm to about 30 μm, about 5 μm to about 30 μm, about 10 μm to about 20 μm, about 10 μm to about 40 μm, about 20 μm to about 50 μm, about 40 μm to about 50 μm, or about 50 μm to about 70 μm.

[0093] The amount of functional additive relative to 100 parts by weight of the positive electrode active material can range from about 0.03 parts by weight to about 0.3 parts by weight. When the amount of functional additive relative to 100 parts by weight of the positive electrode active material is less than about 0.03 parts by weight, a coating layer may not be formed on the surface of each of the positive electrode active material and the sacrificial positive electrode material. Therefore, residual lithium on the positive electrode active material and the sacrificial positive electrode material may be removed to react with the binder, resulting in the degradation of the binder. When the amount of functional additive relative to 100 parts by weight of the positive electrode active material is greater than about 0.3 parts by weight, the functional additive may act as a resistive material to increase the resistance of the electrode plates, resulting in the degradation of the characteristics of the rechargeable lithium battery.

[0094] According to an example embodiment of this disclosure, the value of Formula 1 below can be in the range of about 0.5 to about 2.

[0095] Formula 1:

[0096] In Formula 1, the term "amount of functional additive" can refer to the weight parts of the functional additive relative to 100 parts by weight of the positive electrode active material layer. In Formula 1, the term "amount of positive electrode active material" can refer to the weight parts of the positive electrode active material relative to 100 parts by weight of the positive electrode active material layer. In Formula 1, the term "amount of sacrificial positive electrode material" can refer to the weight parts of the sacrificial positive electrode material relative to 100 parts by weight of the positive electrode active material layer.

[0097] When the value of Formula 1 is less than about 0.5, residual lithium removed from the positive electrode active material or sacrificial positive electrode material may cause gelation or gas generation in the positive electrode active material slurry. When the value of Formula 1 is greater than about 2, functional additives may cause an increase in electrode plate resistance, which may lead to a decrease in the capacity and cycle life of the rechargeable lithium battery. According to this disclosure, when the above ranges are met, an overall improvement in the stability and capacity of the positive electrode active material can be achieved.

[0098] The following description focuses on azole compounds according to exemplary embodiments of this disclosure.

[0099] The imidazole compounds according to this disclosure may include compounds represented by the following chemical formula 3.

[0100] Chemical formula 3: .

[0101] In chemical formula 3, R can be or include at least one of hydrogen, deuterium, halogen group, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group.

[0102] Triazole compounds according to this disclosure may include compounds represented by the following chemical formula 4.

[0103] Chemical formula 4: .

[0104] In chemical formula 4, Two of Q1, Q2, Q3, and Q4 may be or include nitrogen, and the remaining two of Q1, Q2, Q3, and Q4 may be or include carbon.

[0105] R can be or include at least one of hydrogen, deuterium, halogen group, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group.

[0106] The pyrazole compounds according to this disclosure may include compounds represented by the following chemical formula 5.

[0107] Chemical formula 5: .

[0108] In chemical formula 5, R1 may be or include at least one of hydrogen, deuterium, halogen group, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group.

[0109] R2, R3 and R4 may each be or include at least one of hydrogen, deuterium, nitrogen, oxygen, halogen groups and substituted or unsubstituted alkyl groups.

[0110] Thiazole compounds according to this disclosure may include compounds represented by the following chemical formula 6.

[0111] Chemical formula 6: .

[0112] In chemical formula 6, R1, R2 and R3 may each be or include at least one of hydrogen, deuterium, halogen group, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group.

[0113] The above example embodiments are illustrated by way of example, and this disclosure is not limited to these example embodiments.

[0114] Electrolyte layer In an example embodiment, the electrolyte layer may be disposed separately between the positive and negative electrodes. The electrolyte layer may include a membrane 30 and an electrolyte solution ELL. For example, the entire structure including the membrane 30 and the electrolyte solution ELL may be referred to as the electrolyte layer. The electrolyte layer may be in the form of a layer with a certain thickness.

[0115] In an example embodiment, the electrolyte layer may be or include a gel polymer electrolyte layer comprising a gel polymer electrolyte. When a gel polymer electrolyte (or semi-solid electrolyte) is included, the liquid electrolyte and the gel polymer electrolyte comprising a crosslinked polymer may be included in the pores of the porous substrate constituting the membrane 30. In this structure, the liquid electrolyte can be impregnated into the crosslinked polymer network having a crosslinked structure, and thus leakage can be prevented or blocked.

[0116] In an example embodiment, the electrolyte layer may be or include a solid electrolyte layer comprising a solid electrolyte. The solid electrolyte layer may be configured to perform the functions of the diaphragm 30 and the electrolyte solution ELL.

[0117] When a rechargeable lithium battery includes a gel polymer electrolyte (or a semi-solid electrolyte) and a solid electrolyte, the electrolyte layer can be configured to perform the functions of a separator 30 and an electrolyte solution ELL.

[0118] Manufacturing of rechargeable lithium batteries The following description focuses on a method of manufacturing a rechargeable lithium battery according to an example embodiment.

[0119] Methods for manufacturing rechargeable lithium batteries may include manufacturing a positive electrode, manufacturing a negative electrode, and combining the positive and negative electrodes together to manufacture the battery.

[0120] For example, the fabrication of the positive electrode may include mixing a positive electrode active material, a sacrificial positive electrode material, a conductive material, a binder, and functional additives to prepare a positive electrode active material slurry, and coating the positive electrode active material slurry onto a current collector to form a positive electrode active material layer. Functional additives may include compounds containing azole compounds.

[0121] Manufacturing of positive electrode Positive electrode active material, sacrificial positive electrode material, conductive material, binder, and functional additives can be mixed to prepare a positive electrode active material slurry. In the mixing process, any method that can be used by those skilled in the art (such as wet or dry methods) can be utilized, and is not limited to any particular method.

[0122] In preparing the positive electrode active material slurry, the positive electrode active material, sacrificial positive electrode material, conductive material, and binder may each include the materials described above. For example, a high-nickel positive electrode active material may be included as the positive electrode active material.

[0123] When preparing the slurry of the positive electrode active material, sacrificial positive electrode material and functional additives can be added. Since the functional additives are the same as those discussed above, their description is omitted, and the method for manufacturing the positive electrode will be explained in detail.

[0124] Functional additives can be added during the mixing and preparation of the positive electrode active material slurry, thus solving the problem of performance degradation that occurs during the manufacture of the positive electrode. As a result, the positive electrode can be improved in terms of processability and performance. Sacrificial positive electrode material can be added in an amount ranging from about 1 part by weight to about 15 parts by weight relative to 100 parts by weight of the positive electrode active material slurry. Functional additives can be added in an amount ranging from about 0.03 parts by weight to about 0.3 parts by weight relative to 100 parts by weight of the positive electrode active material slurry.

[0125] In preparing the positive electrode active material slurry, increasing the amount of sacrificial positive electrode material may lead to an increase in the amount of functional additives added. Therefore, functional additives can form a coating layer on the surface of the sacrificial positive electrode material to reduce or prevent lithium loss from within the material. Functional additives can also form a coating layer on the surface of the positive electrode active material to reduce or prevent lithium loss from within it.

[0126] It can effectively solve problems such as gas generation and increased resistance caused by side reactions with the atmosphere and / or moisture during the mixing step of the positive electrode active material slurry. It can also effectively solve problems such as the formation of lithium compounds, the deterioration of binders, and the aggregation of conductive materials, which may ultimately lead to the gelation of the positive electrode active material slurry.

[0127] Furthermore, functional additives can be uniformly mixed in the positive electrode active material slurry, thus forming a positive electrode active material layer in which the sacrificial positive electrode material and functional additives are uniformly distributed. Even when the positive electrode active material layer is manufactured on a thick-film electrode plate, processability and stability can be improved during battery manufacturing. In summary, batteries with improved manufacturing processability, stability, and capacity can be manufactured. In example embodiments, the thickness of the positive electrode active material layer can be in the range of about 5 μm to about 70 μm (e.g., about 10 μm to about 30 μm, about 5 μm to about 30 μm, about 10 μm to about 20 μm, about 10 μm to about 40 μm, about 20 μm to about 50 μm, about 40 μm to about 50 μm, or about 50 μm to about 70 μm).

[0128] In the example, the prepared positive electrode active material slurry can be coated onto the positive electrode current collector and dried, and then pressed to form a positive electrode active material layer.

[0129] Manufacturing of negative electrode A negative electrode active material, binder, and conductive material can be mixed to prepare a negative electrode active material slurry. The prepared negative electrode active material slurry can be coated onto a negative electrode current collector and dried, and then pressed to manufacture a negative electrode.

[0130] Battery manufacturing The manufactured positive and negative electrodes can be combined to create a fully assembled rechargeable lithium battery. A separator can be placed between the positive and negative electrodes, and an electrolyte solution can be introduced to manufacture the battery. Optionally, an electrolyte layer can be provided between the positive and negative electrodes to create a stacked battery.

[0131] Figure 8This is a flowchart illustrating a method for manufacturing a rechargeable lithium-ion battery according to an example embodiment. In the example, method 800 includes operation 810, which includes mixing a positive electrode active material, a sacrificial positive electrode material, a conductive material, a binder, and a functional additive to prepare a positive electrode active material slurry. For example, the amount of the functional additive is in the range of about 0.03 parts by weight to about 0.3 parts by weight relative to 100 parts by weight of the positive electrode active material. In another example, the functional additive includes an azole compound, and the azole compound includes a functional group comprising at least one of imidazole, triazole, pyrazol, and thiazolyl groups. In another example, the amount of the sacrificial positive electrode material is in the range of about 1 part by weight to about 15 parts by weight relative to 100 parts by weight of the positive electrode active material slurry. For example, the sacrificial positive electrode material includes a compound represented by Chemical Formula 1: Li a XO b Furthermore, in Formula 1, 2 ≤ a ≤ 10 and 2 ≤ b ≤ 5, and X includes at least one of Ni, Fe, and Co. In yet another example, the amount of positive electrode active material is in the range of about 85 parts by weight to about 98 parts by weight relative to 100 parts by weight of the positive electrode active material slurry. Operation 820 includes coating the positive electrode active material slurry onto the current collector to form a positive electrode active material layer. For example, forming the positive electrode active material slurry includes forming a coating layer on the surface of at least one of the positive electrode active material and the sacrificial positive electrode material, wherein the coating layer includes functional additives.

[0132] This disclosure is applicable to any battery that includes a positive electrode active material layer, such as typical lithium-ion batteries, solid-state batteries, or semi-solid-state batteries. Furthermore, this disclosure is not limited to any particular shape and can be manufactured in commonly included shapes, such as prismatic, pouch, and cylindrical shapes.

[0133] The following describes detailed exemplary embodiments for implementing this disclosure. This disclosure includes not only the exemplary embodiments described above, but also embodiments that can be readily modified or simply redesigned. Furthermore, this disclosure includes techniques that can be readily modified and implemented using the described exemplary embodiments. Therefore, the scope of this disclosure should not be limited to the foregoing exemplary embodiments, but should be defined by the appended claims and their equivalents.

[0134] Example 1: Preparation of positive electrode paste 95.4 wt% of LiNi was used as the positive electrode active material. 0.94 Co 0.04 Al 0.02O2, 1.2 wt% polyvinylidene fluoride as a binder, and 0.35 wt% carbon nanotubes as a conductive material were mixed in N-methylpyrrolidone solvent to prepare a positive electrode active material slurry. The positive electrode active material slurry contained 3 wt% Li2NiO2 as a sacrificial positive electrode material and 0.05 wt% functional additives including compounds containing pyrazole groups.

[0135] Example 2: Preparation of positive electrode paste The positive electrode active material slurry contains 0.05 wt% of a functional additive comprising a triazole group. Except for this difference, the positive electrode slurry is prepared using the same method as in Example 1.

[0136] Example 3: Preparation of positive electrode paste The positive electrode active material slurry contains 0.05 wt% of a functional additive comprising a compound containing an imidazole group. Except for this difference, the positive electrode slurry is prepared using the same method as in Example 1.

[0137] Example 4: Preparation of positive electrode paste The positive electrode active material slurry contains 0.05 wt% of a functional additive comprising a thiazole group. Except for this difference, the positive electrode slurry is prepared using the same method as in Example 1.

[0138] Example 5: Preparation of positive electrode paste The positive electrode active material slurry contains 3 wt% Li5FeO4 as a sacrificial positive electrode material and 0.05 wt% functional additives including compounds containing triazole groups. Except for this difference, the positive electrode slurry is prepared using the same method as in Example 1.

[0139] Comparative Example 1: Preparation of Positive Electrode Slurry The positive electrode active material slurry contains 98.35 wt% LiNi as the positive electrode active material. 0.94 Co 0.04 Al 0.02 O2 and 0.1 wt% of functional additives including oxalic acid without sacrificing the positive electrode material. Except for this difference, the positive electrode slurry was prepared in the same manner as in Example 1.

[0140] Comparative Example 2: Preparation of Positive Electrode Slurry The positive electrode active material slurry contains 95.35 wt% LiNi as the positive electrode active material. 0.94 Co 0.04 Al 0.02O2 and 0.1 wt% of functional additives including oxalic acid. Except for this difference, the positive electrode slurry was prepared using the same method as in Example 1.

[0141] Comparative Example 3: Preparation of Positive Electrode Slurry The positive electrode active material slurry contains 95.35 wt% LiNi as the positive electrode active material. 0.94 Co 0.04 Al 0.02 O2 and 3 wt% Li5FeO4 as a sacrificial positive electrode material and 0.1 wt% functional additives including oxalic acid. Except for this difference, the positive electrode slurry was prepared in the same manner as in Example 1.

[0142] Comparative Example 4: Preparation of Positive Electrode Slurry The positive electrode active material slurry contains 80.3 wt% LiNi as the positive electrode active material. 0.94 Co 0.04 Al 0.02 O2, 18 wt% Li2NiO2 as a sacrificial positive electrode material, and 0.15 wt% functional additives comprising compounds containing triazole groups. Except for this difference, the positive electrode slurry was prepared using the same method as in Example 1.

[0143] Comparative Example 5: Preparation of Positive Electrode Slurry The positive electrode active material slurry contains 95.44 wt% LiNi as the positive electrode active material. 0.94 Co 0.04 Al 0.02 O2 and 0.01 wt% of a functional additive comprising a triazole group. Except for this difference, the positive electrode slurry was prepared using the same method as in Example 1.

[0144] Comparative Example 6: Preparation of Positive Electrode Slurry The positive electrode active material slurry contains 95.3 wt% LiNi as the positive electrode active material. 0.94 Co 0.04 Al 0.02 O2 and 0.15 wt% of functional additives including compounds containing triazole groups. Except for this difference, the positive electrode slurry was prepared using the same method as in Example 1.

[0145] Table 1 below lists manufacturing embodiments and comparative examples of this disclosure. The amount of each material listed in Table 1 is expressed as parts by weight relative to 100 parts by weight of the positive electrode active material slurry.

[0146] Table 1:

[0147] Evaluation 1: Gelation of the slurry left after stirring Functional additives were added to prepare a slurry, and the slurry was left to stand to observe whether gelation occurred. The results are listed in Table 2 below.

[0148] Table 2:

[0149] The positive electrode active material slurry according to the embodiments of this disclosure did not gel even after the passage of time. In contrast, the positive electrode active material slurries according to Comparative Examples 1 to 5 gelled within two to five days.

[0150] Referring to Comparative Examples 1 to 3, it can be observed that the slurry without functional additives containing azole compounds rapidly gels. Referring to Comparative Example 4, it can be observed that when the amount of sacrificial positive electrode material added is greater than approximately 15 parts by weight, slurry gelation occurs, thereby reducing the efficiency of the battery cells and thus degrading their characteristics. Referring to Comparative Example 5, it can be observed that when the value of Equation 1 is less than approximately 0.5, slurry gelation occurs and particles aggregate to increase the resistance of the battery cells, thus degrading their characteristics. Referring to Comparative Example 6, it can be observed that when the value of Equation 1 is greater than approximately 2, the functional additives cause an increase in the resistance of the battery cells, thus reducing their performance.

[0151] Therefore, it can be determined that in order to reduce or prevent slurry gelation and improve the performance of battery cells, the amount of functional additives needs to be adjusted so that the value of Equation 1 is equal to or greater than about 0.5 and less than about 2.

[0152] Evaluation 2: Cycle life Cycle life characteristics were evaluated after manufacturing coin cell cells containing positive electrodes made with the positive electrode active material slurries of the examples and comparative examples. The results are listed in Table 3 below.

[0153] Table 3:

[0154] Referring to Comparative Example 6, it can be observed that no gelation of the positive electrode active material slurry occurred, but the cycle life characteristics deteriorated. It can be seen that the battery according to the embodiment exhibits desirable or improved cycle life characteristics compared to the battery according to the Comparative Example.

[0155] In summary, it can be determined that functional additives are included to protect the surface of the positive electrode active material, thereby improving stability.

[0156] The positive electrode according to the example embodiment can exhibit an improved effect on protecting the surface of the positive electrode active material, thereby improving the cycle life and output characteristics of the rechargeable battery.

[0157] The manufacturing method according to the example embodiment can solve the stability problem of rechargeable batteries.

Claims

1. A positive electrode active material layer, the positive electrode active material layer comprising: Positive electrode active material; Sacrificial positive electrode material; Functional additives; Conductive materials; as well as Adhesive, The functional additives include azole compounds, and The amount of the functional additive is in the range of 0.03 parts by weight to 0.3 parts by weight relative to 100 parts by weight of the positive electrode active material layer.

2. The positive electrode active material layer according to claim 1, wherein, The amount of the sacrificial positive electrode material is in the range of 1 to 15 parts by weight relative to 100 parts by weight of the positive electrode active material layer.

3. The positive electrode active material layer according to claim 1, wherein, The azole compounds include functional groups comprising at least one of imidazole, triazole, pyrazol, and thiazolyl groups.

4. The positive electrode active material layer according to claim 1, wherein, The amount of the positive electrode active material is in the range of 85 to 98 parts by weight relative to 100 parts by weight of the positive electrode active material layer.

5. The positive electrode active material layer according to claim 1, wherein the positive electrode active material layer further comprises: Residual lithium is present on the surface of at least one of the positive electrode active material and the sacrificial positive electrode material. The amount of residual lithium is in the range of 0.01 parts by weight to 4 parts by weight relative to 100 parts by weight of the positive electrode active material layer.

6. The positive electrode active material layer according to claim 5, wherein, The amount of residual lithium on the surface of the positive electrode active material is less than the amount of residual lithium on the surface of the sacrificial positive electrode material.

7. The positive electrode active material layer according to claim 5, wherein: The amount of residual lithium on the surface of the positive electrode active material is in the range of 1 to 4 parts by weight relative to 100 parts by weight of the positive electrode active material. The amount of residual lithium on the surface of the sacrificial positive electrode material is in the range of 2 to 10 parts by weight relative to 100 parts by weight of the sacrificial positive electrode material.

8. The positive electrode active material layer according to claim 1, wherein, The sacrificial positive electrode material comprises a compound represented by chemical formula 1. Chemical Formula 1: At the a XO b , In chemical formula 1, 2≤a≤10 and 2≤b≤5, and X includes at least one of Ni, Fe, and Co.

9. The positive electrode active material layer according to claim 1, wherein: The functional additive is present in a first amount relative to the positive electrode active material layer. The positive electrode active material exists in a second amount relative to the positive electrode active material layer, and The sacrificial positive electrode material exists in a third quantity relative to the positive electrode active material layer. The value of Equation 1 is in the range of 0.5 to 2. Formula 1: 。 10. A rechargeable lithium battery, said rechargeable lithium battery comprising: Positive electrode; negative electrode; as well as An electrolyte layer is located between the positive electrode and the negative electrode. The positive electrode comprises: a positive electrode current collector; and a positive electrode active material layer, on which the positive electrode current collector is disposed. The positive electrode active material layer comprises: a positive electrode active material; a sacrificial positive electrode material; a functional additive; a conductive material; and a binder. The functional additives include azole compounds. Wherein, the functional additive, the positive electrode active material, and the sacrificial positive electrode material are present in a first amount, a second amount, and a third amount, respectively, relative to the positive electrode active material layer, and The value of Equation 1 is in the range of 0.5 to 2. Formula 1: 。 11. The rechargeable lithium battery according to claim 10, wherein, The azole compounds include functional groups comprising at least one of imidazole, triazole, pyrazol, and thiazolyl groups.

12. The rechargeable lithium battery according to claim 10, wherein, The sacrificial positive electrode material comprises a compound represented by chemical formula 1. Chemical Formula 1: At the a XO b , In chemical formula 1, 2≤a≤10 and 2≤b≤5, and X includes at least one of Ni, Fe, and Co.

13. The rechargeable lithium battery according to claim 10, further comprising: Residual lithium is present on the surface of at least one of the positive electrode active material and the sacrificial positive electrode material. The amount of residual lithium is in the range of 0.01 parts by weight to 4 parts by weight relative to 100 parts by weight of the positive electrode active material layer.

14. The rechargeable lithium battery according to claim 13, wherein: The amount of residual lithium on the surface of the positive electrode active material is in the range of 1 to 4 parts by weight relative to 100 parts by weight of the positive electrode active material. The amount of residual lithium on the surface of the sacrificial positive electrode material is in the range of 2 to 10 parts by weight relative to 100 parts by weight of the sacrificial positive electrode material.

15. The rechargeable lithium battery according to claim 10, further comprising: A coating layer is applied to the surface of at least one of the positive electrode active material and the sacrificial positive electrode material. The coating layer includes the functional additive.

16. A method for manufacturing a rechargeable lithium battery, the method comprising the following steps: A slurry of positive electrode active material is prepared by mixing positive electrode active material, sacrificial positive electrode material, conductive material, binder and functional additives. as well as The positive electrode active material slurry is coated onto the current collector to form a positive electrode active material layer. The amount of the functional additive is in the range of 0.03 parts by weight to 0.3 parts by weight relative to 100 parts by weight of the positive electrode active material. The amount of the sacrificial positive electrode material is in the range of 1 to 15 parts by weight relative to 100 parts by weight of the positive electrode active material slurry.

17. The method according to claim 16, wherein, The functional additives include azole compounds. The azole compounds include functional groups comprising at least one of imidazole, triazole, pyrazol, and thiazolyl groups.

18. The method according to claim 16, wherein, The amount of the positive electrode active material is in the range of 85 to 98 parts by weight relative to 100 parts by weight of the positive electrode active material slurry.

19. The method of claim 16, wherein, The sacrificial positive electrode material comprises a compound represented by chemical formula 1. Chemical Formula 1: At the a XO b , In chemical formula 1, 2≤a≤10 and 2≤b≤5, and X includes at least one of Ni, Fe, and Co.

20. The method of claim 16, wherein, The step of forming the positive electrode active material slurry includes forming a coating layer on the surface of at least one of the positive electrode active material and the sacrificial positive electrode material. The coating layer includes the functional additive.

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