Rechargeable lithium battery

Abstract

The invention relates to a rechargeable lithium battery. The rechargeable lithium battery includes: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte. The electrolyte includes a nitrile-based additive. The positive electrode active material includes at least one element selected from the group consisting of compounds represented by Lia1Fex1B1y1PO4-b1 and Lia2Mnz2Fex2B1y2PO4-b2, wherein B1 is at least one element selected from the group consisting of Ti, Mg, V, and Nb.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0034694, filed on March 12, 2024, in the Korean Intellectual Property Office, the entire contents of which are hereby incorporated by reference. Technical Field

[0003] One or more embodiments of the present disclosure relate to a rechargeable lithium battery. Background Art

[0004] Recently, with the rapid spread and popularization of batteries for electronic devices (such as mobile phones, laptop computers and / or electric vehicles), the demand for such batteries (e.g., rechargeable lithium batteries) having relatively high energy density and high capacity has rapidly increased. Therefore, intensive research has been conducted to improve the performance of such rechargeable batteries (e.g., rechargeable lithium batteries).

[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 capable of intercalating and deintercalating lithium ions, and when the lithium ions are intercalated and deintercalated, electric energy is generated due to oxidation and reduction reactions. Summary of the Invention

[0006] One or more aspects of embodiments of the present disclosure are directed to a rechargeable lithium battery having improved lifespan and high-temperature storage characteristics.

[0007] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0008] According to one or more embodiments of the present disclosure, a rechargeable lithium battery may include: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte. The electrolyte may include a nitrile additive. The positive electrode active material may include at least one selected from the group consisting of compounds represented by Chemical Formula 1 and Chemical Formula 2.

[0009] Chemical formula 1

[0010] Li a1 Fe x1 B 1 y1 PO 4-b1

[0011] In Chemical Formula 1, a1, x1, y1, and b1 may satisfy 0.8≤a1≤1.2, 0.9≤x1≤1.1, 0≤y1≤0.05, and 0≤b1≤0.05.

[0012] Chemical formula 2

[0013] Li a2 Mn z2 Fe x2 B 1 y2 PO 4-b2

[0014] In Chemical Formula 2, a2, z2, x2, y2, and b2 may satisfy 0.8≤a2≤1.2, 0.5≤z2≤0.9, 0.1≤x2≤0.5, 0≤y2≤0.05, 0≤b2≤0.05, and 0.9≤z2+x2≤1.2.

[0015] In Chemical Formula 1 and Chemical Formula 2, B 1 It may be at least one element selected from titanium (Ti), magnesium (Mg), vanadium (V), and niobium (Nb).

[0016] The nitrile additive may include at least one selected from the group consisting of compounds represented by Chemical Formula 3, Chemical Formula 4, and Chemical Formula 5.

[0017] Chemical formula 3

[0018] RC≡N,

[0019] In Chemical Formula 3, R is a substituted or unsubstituted C1-C10 alkyl group,

[0020] Chemical formula 4

[0021]

[0022] In Chemical Formula 4, k is an integer selected from 0 to 10, and

[0023] Chemical formula 5

[0024]

[0025] In Chemical Formula 5, l, m, and n may each independently be an integer selected from 0 to 10, and may be integers different from each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings.

[0027] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to one or more embodiments of the present disclosure is illustrated.

[0028] Figures 2 to 5 Each illustrates a simplified conceptual diagram showing a rechargeable lithium battery according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0029] In order to fully understand the configuration and aspects of the present disclosure, one or more embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted, however, that the present disclosure is not limited to the following example embodiments and can be implemented in one or more suitable forms. On the contrary, the example embodiments are provided only to illustrate the present disclosure and to allow those skilled in the art to fully understand the scope of the present disclosure.

[0030] In the present disclosure, it will be understood that if (for example, when) an element is referred to as being "on" another element, the element may be directly on the other element or intervening elements may be present therebetween. In contrast, if (for example, when) an element is referred to as being "directly on" another element, there are no intervening elements. In the drawings, the size (for example, thickness) of some components may be exaggerated for effective explanation of the technical content. The same reference numerals refer to the same elements throughout the specification, and their repeated description may not be provided in the specification.

[0031] Unless otherwise specifically stated in the present disclosure, the singular forms "a", "an" and "the" are intended to include plural expressions as well, unless the context clearly indicates otherwise. Further, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure." In addition, unless otherwise specifically stated, the phrases "A or B" or "A and / or B" or "A / B" may indicate "A but not B", "B but not A", and "A and B". The terms "comprises / includes" and / or "comprising / including" used in the present disclosure do not exclude the presence or addition of one or more other components.

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

[0033] In the present disclosure, unless separately limited otherwise, the term "substituted" may refer to a substituent or at least one hydrogen of a compound being replaced by deuterium, halogen, hydroxy, amino, C1-C30 amine, nitro, C1-C40 silyl, C1-C30 alkyl, C1-C10 alkylsilyl, C6-C30 arylsilyl, C3-C30 cycloalkyl, C3-C30 heterocycloalkyl, C6-C30 aryl, C2-C30 heteroaryl, C1-C20 alkoxy, C1-C10 fluoroalkyl, cyano and / or combinations thereof (e.g., any suitable combination thereof).

[0034] For example, in one or more embodiments, the term "substituted" may refer to the replacement of at least one hydrogen of a substituent or compound by deuterium, halogen, C1-C30 alkyl, C1-C10 alkylsilyl, C6-C30 arylsilyl, C3-C30 cycloalkyl, C3-C30 heterocycloalkyl, C6-C30 aryl, C2-C30 heteroaryl, C1-C10 fluoroalkyl, or cyano. In one or more embodiments, the term "substituted" may refer to the replacement of at least one hydrogen of a substituent or compound by deuterium, halogen, C1-C20 alkyl, C6-C30 aryl, C1-C10 fluoroalkyl, or cyano. In one or more embodiments, the term "substituted" may refer to the replacement of at least one hydrogen of a substituent or compound by deuterium, halogen, C1-C5 alkyl, C6-C18 aryl, C1-C5 fluoroalkyl, or cyano. In one or more embodiments, the term "substituted" may refer to a substituent or a compound in which at least one hydrogen is replaced by deuterium, cyano, halogen, methyl, ethyl, propyl, butyl, phenyl, biphenyl, terphenyl, trifluoromethyl or naphthyl. Alkyl groups include straight-chain alkyl, branched-chain alkyl or cycloalkyl.

[0035] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to one or more embodiments of the present disclosure is illustrated. Figure 1 , a rechargeable lithium battery may include a positive electrode 10, a negative electrode 20, a separator 30, and an electrolyte ELL.

[0036] The positive electrode 10 and the negative electrode 20 may be spaced and / or separated (e.g., spaced or separated) from each other across the separator 30. The separator 30 may be disposed between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20, and the separator 30 may be in contact with the electrolyte ELL. For example, the positive electrode 10, the negative electrode 20, and the separator 30 may be immersed in (and / or impregnated with) the electrolyte ELL.

[0037] The electrolyte ELL may be a medium through which lithium ions migrate and transfer between the positive electrode 10 and the negative electrode 20. In the electrolyte ELL, the lithium ions may move toward (eg, selected from) one of the positive electrode 10 and the negative electrode 20 through the separator 30.

[0038] Positive electrode 10

[0039] The positive electrode 10 for a rechargeable lithium battery may include a positive electrode current collector COL1 and a positive electrode active material layer AML1 formed on the positive electrode current collector COL1. The positive electrode active material layer AML1 may include a positive electrode active material (e.g., a positive electrode active material in the form of particles) and may further include a binder and / or a conductive material (e.g., an electron conductor).

[0040] For example, in one or more embodiments, the positive electrode 10 may further include an additive that may function as a sacrificial positive electrode.

[0041] The amount of the positive electrode active material may range from about 90 wt % to about 99 wt % based on 100 wt % of the total weight of the positive electrode active material layer AML1. The amount of the binder and the conductive material may each range from about 0.5 wt % to about 5 wt % based on 100 wt % of the total weight of the positive electrode active material layer AML1.

[0042] The binder can be used to improve the adhesion between the positive electrode active material particles and also improve the adhesion between the positive electrode active material and the positive electrode current collector COL1. The binder may include, for example, one or more selected from polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, and nylon, but the embodiments of the present disclosure are not limited thereto.

[0043] Conductive materials (e.g., electrically conductive materials or electron conductive materials) can be used to provide electrode conductivity, and any suitable conductive material that does not cause chemical changes in the rechargeable lithium battery can be used as the conductive material constituting the rechargeable lithium battery. The conductive material may include, for example, 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 including one or more of copper, nickel, aluminum, and silver (e.g., selected from one or more of copper, nickel, aluminum, and silver); conductive polymers such as polyphenylene derivatives; and / or mixtures thereof (e.g., any suitable mixtures thereof).

[0044] In one or more embodiments, an aluminum (Al) foil may be used as the positive electrode current collector COL1 , but embodiments of the present disclosure are not limited thereto.

[0045] Positive electrode active material

[0046] The positive electrode active material in the positive electrode active material layer AML1 may include a compound that can reversibly intercalate and deintercalate lithium (e.g., a lithiated intercalation compound). For example, in one or more embodiments, the positive electrode active material may include at least one type of composite oxide containing lithium and a metal selected from cobalt, manganese, nickel, and / or a combination thereof (e.g., any suitable combination thereof).

[0047] The composite oxide may include lithium transition metal composite oxides, for example, lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds (for example, LiFePO4 (LFP) and LiFe 0.4 Mn 0.6 PO4(LMFP)), cobalt-free nickel-manganese-based oxides, and / or combinations thereof (eg, any suitable combination thereof).

[0048] For example, in one or more embodiments, the positive electrode active material may include a compound represented by one selected from the following chemical formulas: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4- c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Lia Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); and Li a FePO4(0.90≤a≤1.8).

[0049] In the aforementioned chemical formula, A may be nickel (Ni), cobalt (Co), manganese (Mn), and / or a combination thereof (e.g., any suitable combination thereof), X may be Al, Ni, Co, Mn, chromium (Cr), iron (Fe), Mg, strontium (Sr), V, a rare earth element, and / or a combination thereof (e.g., any suitable combination thereof), D may be oxygen (O), fluorine (F), sulfur (S), phosphorus (P), and / or a combination thereof (e.g., any suitable combination thereof), G may be Al, Cr, Mn, Fe, Mg, lanthanum (La), cerium (Ce), Sr, V, and / or a combination thereof (e.g., any suitable combination thereof), and L 1 It can be Mn, Al, and / or combinations thereof (eg, any suitable combination thereof).

[0050] In one or more embodiments, the positive electrode active material may include an olivine-based positive electrode active material. The positive electrode active material may include at least one selected from the group consisting of compounds represented by Chemical Formula 1 and Chemical Formula 2.

[0051] Chemical formula 1

[0052] Li a1 Fe x1 B 1 y1 PO 4-b1

[0053] In Chemical Formula 1, 0.8≤a1≤1.2, 0.9≤x1≤1.1, 0≤y1≤0.05, and 0≤b1≤0.05.

[0054] Chemical formula 2

[0055] Li a2 Mn z2 Fe x2 B 1 y2 PO 4-b2

[0056] In Chemical Formula 2, 0.8≤a2≤1.2, 0.5≤z2≤0.9, 0.1≤x2≤0.5, 0≤y2≤0.05, 0≤b2≤0.05, and 0.9≤z2+x2≤1.2.

[0057] In Chemical Formula 1 and Chemical Formula 2, B 1 It may be at least one element selected from Ti, Mg, V, and Nb, and may be a dopant incorporated into the positive electrode active material particles.

[0058] Compared to other positive electrode active materials, olivine-based positive electrode active materials can be inexpensive and can have excellent or appropriate stability and lifespan characteristics. In addition, if (for example, when) the nitrile additive described later is used together with the olivine-based positive electrode active material, the rechargeable lithium battery can improve lifespan and storage characteristics compared to using other positive electrode active materials. This effect may be caused by the excellent or appropriate reactivity of the Fe element and CN group in the olivine-based positive electrode active material.

[0059] Negative electrode 20

[0060] The negative electrode 20 for a rechargeable lithium battery may include a negative electrode current collector COL2 and a negative electrode active material layer AML2 located on the negative electrode current collector COL2. The negative electrode active material layer AML2 may include a negative electrode active material (e.g., a negative electrode active material in the form of particles) and may further include a binder and / or a conductive material (e.g., an electron conductor).

[0061] For example, in one or more embodiments, the negative electrode active material layer AML2 may include about 90 wt % to about 99 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 100 wt % of the total weight of the negative electrode active material layer AML2.

[0062] The binder can be used to improve the binding of the negative electrode active material particles to each other and also to improve the binding of the negative electrode active material to the negative electrode current collector COL 2. The binder can include a non-aqueous binder (e.g., a water-insoluble binder), an aqueous binder (e.g., a water-soluble binder), a dry binder, and / or a combination thereof (e.g., any suitable combination thereof).

[0063] The non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, and / or combinations thereof (eg, any suitable combination thereof).

[0064] The aqueous binder may include styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol and / or combinations thereof (e.g., any suitable combination thereof).

[0065] When an aqueous binder is used as a binder in the negative electrode active material layer AML2, a cellulose compound capable of providing viscosity may be further included. The cellulose compound may include one or more selected from carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and alkali metal salts thereof. The alkali metal may include Na, K, or Li.

[0066] The dry binder can include a fibrillated polymeric material, such as polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and / or combinations thereof (eg, any suitable combination thereof).

[0067] Conductive materials (e.g., electrically conductive materials or electron conductive materials) can be used to provide conductivity to the electrodes, and any suitable conductive material that does not cause chemical changes in the rechargeable lithium battery can be used as the conductive material constituting the rechargeable lithium battery. For example, in one or more embodiments, the conductive material may include: carbon-based materials such as 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 selected from copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; and / or mixtures thereof (e.g., any suitable mixture thereof).

[0068] The negative electrode current collector COL2 may include copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a conductive metal-coated polymer substrate, and / or combinations thereof (eg, any suitable combination thereof).

[0069] Negative electrode active material

[0070] The negative electrode active material in the negative electrode active material layer AML2 may include a material that can reversibly intercalate and deintercalate lithium ions, lithium metal, a lithium metal alloy, a material that can dope and dedope lithium, or a transition metal oxide.

[0071] Materials that can reversibly embed and deembed lithium ions may include carbonaceous negative electrode active materials, for example, crystalline carbon, amorphous carbon, and / or combinations thereof (e.g., any suitable combination thereof). For example, crystalline carbon may include graphite, such as natural graphite and / or artificial graphite that is amorphous (e.g., irregularly shaped), flaky, lamellar, spherical, or fibrous, and amorphous carbon may include soft carbon, hard carbon, mesophase pitch carbon, and / or calcined coke.

[0072] Lithium metal alloys may include alloys of lithium with metals selected from sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), silicon (Si), antimony (Sb), lead (Pb), indium (In), zinc (Zn), barium (Ba), radium (Ra), germanium (Ge), aluminum (Al), and tin (Sn).

[0073] Materials that can be doped and undoped with lithium may include Si-based negative electrode active materials or Sn-based negative electrode active materials. Si-based negative electrode active materials may include silicon, silicon-carbon composites, SiO x (0 < x ≤ 2) (e.g., SiO2), Si-Q alloys (where Q is an alkali metal, alkaline earth metal, Group 13 element, Group 14 element (except Si), Group 15 element, Group 16 element, transition metal, rare earth element, and / or combinations thereof (e.g., any suitable combination thereof)) and / or combinations thereof (e.g., any suitable combination thereof). Sn-based negative electrode active materials may include Sn, SnO k (0 < k ≤ 2) (e.g., SnO2), Sn-based alloys, or combinations thereof (e.g., any suitable combination thereof).

[0074] The silicon-carbon composite may be a composite of silicon and amorphous carbon (e.g., a composite of silicon and amorphous carbon in particulate form). According to one or more embodiments, the silicon-carbon composite may have a structure in which amorphous carbon is coated on the surface of each silicon particle. For example, in one or more embodiments, the silicon-carbon composite may include secondary particles (cores) in which primary silicon particles are aggregated and an amorphous carbon coating (shell) on the surface of the secondary particles (e.g., located 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.

[0075] In one or more embodiments, the silicon-carbon composite may further 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 on the surface of the core.

[0076] In one or more embodiments, Si-based negative electrode active materials and / or Sn-based negative electrode active materials may be used in combination with carbonaceous negative electrode active materials.

[0077] Diaphragm 30

[0078] Depending on the type or kind of rechargeable lithium battery, the separator 30 may be present between the positive electrode 10 and the negative electrode 20. The separator 30 may include one or more selected from a polyethylene separator, a polypropylene separator, and a polyvinylidene fluoride separator, or may be a multilayer separator thereof, such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator.

[0079] The separator 30 may include a porous substrate and a coating on a surface (eg, one surface or two opposing surfaces) of the porous substrate, and the coating may include an organic material, an inorganic material, and / or a combination thereof (eg, any appropriate combination thereof).

[0080] The porous substrate may be a polymer layer comprising one selected from polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyetherketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, and polytetrafluoroethylene (e.g., Teflon), or a copolymer or mixture comprising two or more thereof.

[0081] The organic material may include a polyvinylidene fluoride-based copolymer and / or a (meth)acrylic acid-based copolymer.

[0082] The inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof (e.g., any suitable combination thereof), but embodiments of the present disclosure are not limited thereto.

[0083] In one or more embodiments, the organic material and the inorganic material may be mixed in one coating layer, or may be present as a stacked layer of a coating layer including an organic material and a coating layer including an inorganic material.

[0084] Electrolyte ELL

[0085] The electrolyte ELL for a rechargeable lithium battery may include a non-aqueous organic solvent and a lithium salt, and may further include additives.

[0086] The non-aqueous organic solvent may serve as a medium for transporting ions participating in the electrochemical reaction of the rechargeable lithium battery.

[0087] The non-aqueous organic solvent may include a carbonate-based solvent, an ester-based solvent, an ether-based solvent, a ketone-based solvent, an alcohol-based solvent, an aprotic solvent, and / or combinations thereof (eg, any appropriate combination thereof).

[0088] The carbonate-based solvent may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC) and / or butylene carbonate (BC).

[0089] The ester solvent may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonolactone, valerolactone and / or caprolactone.

[0090] Ether solvents may include dibutyl ether, tetraglyme, diglyme, ethylene glycol dimethyl ether, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran and / or tetrahydrofuran. Ketone solvents may include cyclohexanone. Alcohol solvents may include ethanol, isopropanol, etc. Aprotic solvents may include nitriles (such as R-CN (wherein R is a hydrocarbon group having a C2 to C20 linear, branched or cyclic structure, and may include a double bond, an aromatic ring or an ether group)); amides (such as dimethylformamide); dioxolanes (such as 1,3-dioxolane and / or 1,4-dioxolane); and / or sulfolane.

[0091] The nonaqueous organic solvent may be used alone or as a mixture of two or more thereof.

[0092] In addition, if (for example, when) a carbonate-based solvent is used, cyclic carbonate and chain carbonate may be mixed and used, and the cyclic carbonate and chain carbonate may be mixed in a volume ratio of about 1:1 to about 1:9.

[0093] The lithium salt may be a material dissolved in a non-aqueous organic solvent to serve as a supply source of lithium ions in a rechargeable lithium battery, and plays a role in achieving basic operations of the rechargeable lithium battery and promoting the movement of lithium ions between the positive electrode and the negative electrode. The lithium salt may include, for example, a material selected from LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N, lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1SO2) (wherein x and y are integers between 1 and 20), at least one of lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFBOP) and lithium bis(oxalato)borate (LiBOB).

[0094] Rechargeable lithium battery

[0095] Based on the shape of the rechargeable lithium battery, the rechargeable lithium battery can be classified into a cylindrical, prismatic, pouch type or type, or a coin type or type. Figures 2 to 5 middle, Figure 2 A cylindrical rechargeable lithium battery is shown, Figure 3 A prismatic rechargeable lithium battery is shown, and Figure 4 and Figure 5 Each shows a pouch type or type rechargeable lithium battery. Figures 2 to 5 , the rechargeable lithium battery 100 may include an electrode assembly 40 in which a separator 30 is inserted between a positive electrode 10 and a negative electrode 20; and may further include a case 50 in which the electrode assembly 40 is housed. The positive electrode 10, the negative electrode 20, and the separator 30 may be immersed in an electrolyte. In some embodiments, the rechargeable lithium battery 100 may include a sealing member 60 that seals the case 50, such as Figure 2 In some embodiments, as Figure 3 As explained in , the rechargeable lithium battery 100 may include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. In some embodiments, as Figure 4 and Figure 5 As shown in , the rechargeable lithium battery 100 may include an electrode tab 70 , or a positive electrode tab 71 and a negative electrode tab 72 , serving as an electrical path for outwardly guiding current generated in the electrode assembly 40 .

[0096] Hereinafter, an electrolyte for a rechargeable lithium battery according to one or more embodiments of the present disclosure will be described in more detail.

[0097] According to one or more embodiments, an electrolyte for a rechargeable lithium battery may include a lithium salt, a non-aqueous organic solvent, and a nitrile additive. The nitrile additive may include at least one selected from the compounds represented by Chemical Formula 3, Chemical Formula 4, and Chemical Formula 5.

[0098] Chemical formula 3

[0099] RC≡N

[0100] In Chemical Formula 3, R may be a substituted or unsubstituted C1-C10 alkyl group.

[0101] Chemical formula 4

[0102]

[0103] In Chemical Formula 4, k may be an integer selected from 0 to 10.

[0104] Chemical formula 5

[0105]

[0106] In Chemical Formula 5, l, m, and n may each independently be an integer selected from 0 to 10, and may be integers different from each other.

[0107] Nitrile compounds (i.e., nitrile additives) can form a film on the electrode surface during the activation process or initial charge / discharge process, thereby reducing side reactions between the electrode and the electrolyte. When a stable film is formed on the surface of the negative electrode, reductive decomposition can be effectively suppressed or reduced during battery storage, especially during high-temperature storage. Therefore, during high-temperature storage, the increase in battery resistance can be suppressed or reduced, and the battery life characteristics can be improved.

[0108] In addition, the nitrile compound can suppress or reduce gas generation and life shortening caused by transition metal dissolution by forming a complex with the transition metal during the dissolution of the transition metal.

[0109] Nitrile compounds can form a membrane solid electrolyte interface layer (i.e., solid electrolyte interface layer) on the electrode surface during the activation process or initial charge / discharge process, thereby reducing side reactions between the electrode and the electrolyte. When a stable membrane solid electrolyte interface layer is formed on the surface of the negative electrode, reductive decomposition can be effectively suppressed or reduced during battery storage, especially during high-temperature storage. Therefore, during high-temperature storage, the increase in battery resistance can be suppressed or reduced, and the battery life characteristics can be improved.

[0110] The additive (e.g., a nitrile additive) may be included in an amount of about 0.01 wt% to about 5 wt%, about 0.05 wt% to about 5 wt%, about 0.05 wt% to about 4 wt%, about 0.1 wt% to about 4 wt%, or about 0.1 wt% to about 3 wt%, relative to 100 wt% of the total weight of the electrolyte.

[0111] When the amount of the additive is within the above range, the electrolyte may have a suitable or appropriate viscosity and may satisfy wettability to the negative electrode and the positive electrode. When the amount of the additive is within the above range, an effect as a surfactant may be exhibited.

[0112] According to one or more embodiments of the present disclosure, the non-aqueous organic solvent may be a mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC).

[0113] In one or more embodiments, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) may be mixed in a volume ratio of 1:a:b, wherein a may range from about 1 to about 3, and b may range from about 1 to about 5.

[0114] In one or more embodiments, the ethylene carbonate (EC) solvent may be included in an amount of about 5 vol% to about 30 vol%, about 10 vol% to about 30 vol%, or about 10 vol% to about 20 vol%, relative to the total volume of 100 vol% of the non-aqueous organic solvent. The ethyl methyl carbonate (EMC) solvent may be included in an amount of about 20 vol% to about 60 vol%, about 20 vol% to about 50 vol%, or about 30 vol% to about 50 vol%, relative to the total volume of 100 vol% of the non-aqueous organic solvent. The dimethyl carbonate (DMC) solvent may be included in an amount of about 20 vol% to about 60 vol%, about 20 vol% to about 50 vol%, or about 30 vol% to about 50 vol%, relative to the total volume of 100 vol% of the non-aqueous organic solvent.

[0115] In the electrolyte according to some embodiments of the present disclosure, the lithium salt may include LiPF 6 .

[0116] The lithium salt may have a concentration of about 0.1 M to about 2.0 M. For example, in one or more embodiments, the lithium salt may have a concentration equal to or greater than about 0.5 M or 1.0 M. The lithium salt may have a concentration equal to or less than about 2.0 M, equal to or less than about 1.7 M, or equal to or less than about 1.5 M. In the present disclosure, if (for example, when) the lithium salt has a concentration of about 0.1 M to about 2.0 M, the electrolyte may suitably or appropriately maintain its conductivity and viscosity.

[0117] Embodiments of the present disclosure and comparative examples will be described below. However, the following embodiments are merely examples, and the present disclosure is not limited to the discussed embodiments.

[0118] Embodiments and Comparative Examples

[0119] The electrolyte and the rechargeable lithium battery were each manufactured by the following method.

[0120] Implementation Method 1

[0121] (1) Preparation of electrolyte

[0122] 1.5 M LiPF6 was dissolved in a non-aqueous organic solvent (including ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) mixed in a volume ratio of about 20:40:40), and 0.5 wt% of an additive was added relative to 100 wt% of the total weight of the electrolyte to prepare an electrolyte.

[0123] The compound represented by Chemical Formula 5-1 is used as an additive.

[0124] Chemical formula 5-1

[0125]

[0126] (2) Manufacturing of rechargeable lithium batteries

[0127] LiFePO 4 (LFP) as a positive electrode active material, polyvinylidene fluoride as a binder, and carbon black as a conductive material were mixed at a weight ratio of 98:1:1, and the mixture was dispersed in N-methylpyrrolidone to prepare a positive electrode active material slurry.

[0128] The positive electrode active material slurry was coated on an Al foil having a thickness of 20 μm, dried at 100° C., and then pressed to manufacture a positive electrode.

[0129] Graphite as a negative electrode active material, a styrene-butadiene rubber binder, and carboxymethyl cellulose were mixed at a weight ratio of 98:1:1, and the mixture was dispersed in distilled water to prepare a negative electrode active material slurry.

[0130] The negative electrode active material slurry was coated on a Cu foil having a thickness of 10 μm, dried at 100° C., and then pressed to manufacture a negative electrode.

[0131] The positive electrode, the negative electrode, and a polyethylene separator having a thickness of 10 μm were assembled to manufacture an electrode assembly, and an electrolyte was introduced to manufacture a rechargeable lithium battery.

[0132] Implementation Method 2

[0133] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 4-1 was added as an additive at 0.5 wt % when the electrolyte was prepared.

[0134] Chemical formula 4-1

[0135]

[0136] Implementation 3

[0137] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 3-1 was added as an additive at 0.5 wt % when the electrolyte was prepared.

[0138] Chemical formula 3-1

[0139]

[0140] Implementation 4

[0141] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 3-2 was added as an additive at 0.5 wt % when the electrolyte was prepared.

[0142] Chemical formula 3-2

[0143]

[0144] Implementation 5

[0145] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 3-3 was added as an additive at 0.5 wt % when the electrolyte was prepared.

[0146] Chemical formula 3-3

[0147]

[0148] Implementation Method 6

[0149] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 5-1 was added as an additive at 0.1 wt % when the electrolyte was prepared.

[0150] Implementation 7

[0151] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 5-1 was added as an additive at 0.3 wt % when the electrolyte was prepared.

[0152] Implementation 8

[0153] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 5-1 was added as an additive at 1 wt % when the electrolyte was prepared.

[0154] Implementation Method 9

[0155] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 5-1 was added as an additive at 3 wt % when the electrolyte was prepared.

[0156] Implementation 10

[0157] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that the compound represented by Chemical Formula 5-1 was added as an additive at 5 wt % when the electrolyte was prepared.

[0158] Implementation 11

[0159] The electrolyte and the rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that when the rechargeable lithium battery was manufactured, LiFe 0.4 Mn 0.6 PO4(LMFP) was used as the positive electrode active material.

[0160] Implementation 12

[0161] The electrolyte and the rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 6, except that when the rechargeable lithium battery was manufactured, LiFe 0.4 Mn 0.6 PO4 is used as the positive electrode active material.

[0162] Implementation 13

[0163] The electrolyte and the rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 9, except that when the rechargeable lithium battery was manufactured, LiFe 0.4 Mn 0.6 PO4 is used as the positive electrode active material.

[0164] Comparative Example 1

[0165] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that no additive was added when preparing the electrolyte.

[0166] Comparative Example 2

[0167] An electrolyte and a rechargeable lithium battery were each manufactured by substantially the same method as that of Embodiment 11, except that no additive was added when the electrolyte was prepared.

[0168] Comparative Example 3

[0169] The electrolyte and the rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that when the rechargeable lithium battery was manufactured, LiNi 0.8 Co 0.1 Al 0.1 O2(NCA) was used as the positive electrode active material.

[0170] Comparative Example 4

[0171] The electrolyte and the rechargeable lithium battery were each manufactured by substantially the same method as in Embodiment 1, except that when the rechargeable lithium battery was manufactured, LiNi 0.7 Co 0.2 Mn 0.1 O2(NCM) was used as the positive electrode active material.

[0172] Evaluation Example

[0173] The electrolyte and the rechargeable lithium battery were each evaluated by the following methods.

[0174] Evaluation 1: Lifespan characteristics at room temperature

[0175] Each of the rechargeable lithium batteries of Embodiments 1 to 13 and Comparative Examples 1 to 4 was continuously charged and discharged for 800 cycles at room temperature (25°C) under the conditions of 0.5C charge and 0.5C discharge, and the capacity retention rate and DC internal resistance (DC-IR) increase rate after 800 cycles were evaluated. The evaluation results are listed in Tables 1 and 2.

[0176] The capacity retention rate was calculated according to Equation 1, and the DC-IR increase rate was calculated according to Equation 2.

[0177] Equation 1

[0178] Capacity retention (%) = (discharge capacity after 800th cycle (Ah) / discharge capacity after 1st cycle (Ah)) × 100

[0179] Equation 2

[0180] DC-IR increase rate (%) = (DC-IR after the 800th cycle (mΩ) / DC-IR after the 1st cycle (mΩ)) × 100

[0181] Table 1

[0182]

[0183] Referring to Table 1, it can be confirmed that the rechargeable lithium batteries according to Embodiments 1 to 13 each have a high capacity retention rate compared to the rechargeable lithium batteries according to Comparative Examples 1 and 2; and the rechargeable lithium batteries according to Embodiments 1 to 10 each have a low DC-IR increase rate compared to the rechargeable lithium battery according to Comparative Example 1; and the rechargeable lithium batteries according to Embodiments 11 to 13 each have a low DC-IR increase rate compared to the rechargeable lithium battery according to Comparative Example 2. In particular, it can be confirmed that after 800 cycles, the rechargeable lithium battery according to Embodiment 1 has a high capacity retention rate of 90%, and the rechargeable lithium battery according to Embodiment 6 has a low DC-IR increase rate of 125%.

[0184] Table 2

[0185]

[0186] Referring to Table 2, it can be determined that the capacity retention rate of each of the rechargeable lithium batteries of Embodiments 1 and 11 is greater than the capacity retention rate of the rechargeable lithium batteries of Comparative Examples 1 and 2. Each of the rechargeable lithium batteries of Embodiments 1 and 11 uses an olivine-based positive electrode active material (LFP or LMFP) and an electrolyte to which the additive of Chemical Formula 5-1 is added, while no additive is added to the rechargeable lithium batteries of Comparative Examples 1 and 2.

[0187] In addition, since the DC-IR increase rate of the rechargeable lithium battery of Embodiment 1 is smaller than that of the rechargeable lithium battery of Comparative Example 1, and since the DC-IR increase rate of the rechargeable lithium battery of Embodiment 11 is smaller than that of the rechargeable lithium battery of Comparative Example 2, it can be determined that when the electrolyte including the additive of Chemical Formula 5-1 is used, the resistance increase is significantly suppressed.

[0188] Referring back to Table 2, it can be determined that the capacity retention rate of each of the rechargeable lithium batteries of Embodiments 1 and 11 is greater than the capacity retention rate of the rechargeable lithium batteries of Comparative Examples 3 and 4. Each of the rechargeable lithium batteries of Embodiments 1 and 11 uses an olivine-based positive electrode active material (LFP or LMFP) and an electrolyte including the additive of Chemical Formula 5-1, and each of the rechargeable lithium batteries of Comparative Examples 3 and 4 uses a nickel-based positive electrode active material (NCA or NCM) and an electrolyte including the additive of Chemical Formula 5-1.

[0189] Furthermore, since the DC-IR increase rate of each of the rechargeable lithium batteries of Embodiments 1 and 11 was less than that of the rechargeable lithium batteries of Comparative Examples 3 and 4, it was confirmed that each of Embodiments 1 and 11 had a more excellent effect of suppressing the increase in resistance. Accordingly, when the additive of the present disclosure is used together with the olivine-based positive electrode active material, it can maximize or increase the improvement in the lifespan and storage characteristics of the rechargeable lithium battery.

[0190] Evaluation 2: Storage characteristics at high temperatures

[0191] Each of the rechargeable lithium batteries of Embodiments 1 to 13 and Comparative Examples 1 to 4 was charged to an SOC of 100% and then left at 60°C for 60 days. The high-temperature capacity retention rate and high-temperature DC-IR increase rate of the rechargeable lithium batteries were then measured and listed in Tables 3 and 4.

[0192] The high-temperature capacity retention rate was calculated according to Equation 3, and the high-temperature DC-IR increase rate was calculated according to Equation 4.

[0193] Equation 3

[0194] High temperature capacity retention rate (%) = (discharge capacity after 60 days (Ah) / discharge capacity immediately before storage (Ah)) × 100

[0195] Equation 4

[0196] High temperature DC-IR increase rate (%) = (DC-IR after 60 days (mΩ) / DC-IR before storage (mΩ)) × 100

[0197] Table 3

[0198]

[0199] Referring to Table 3, it can be confirmed that each of the rechargeable lithium batteries according to Embodiments 1 to 13 (in which a nitrile additive was added) has a high high-temperature capacity retention rate compared to the rechargeable lithium batteries according to Comparative Examples 1 and 2 (in which no additive was added); and each of the rechargeable lithium batteries according to Embodiments 1 to 10 has a low high-temperature DC-IR increase rate compared to the rechargeable lithium battery according to Comparative Example 1; and each of the rechargeable lithium batteries according to Embodiments 11 to 13 has a low high-temperature DC-IR increase rate compared to the rechargeable lithium battery according to Comparative Example 2. In particular, it can be confirmed that when the rechargeable lithium batteries according to Embodiments 1 and 6 are left at 60°C for 60 days, the rechargeable lithium battery according to Embodiment 1 has a high high-temperature capacity retention rate of 92%, and the rechargeable lithium battery according to Embodiment 6 has a low high-temperature DC-IR increase rate of 131%.

[0200] Table 4

[0201]

[0202] Referring to Table 4, it can be determined that the high-temperature capacity retention rate of each of the rechargeable lithium batteries of Embodiments 1 and 11 is greater than the high-temperature capacity retention rate of the rechargeable lithium batteries of Comparative Examples 1 and 2. Each of the rechargeable lithium batteries in Embodiments 1 and 11 uses an olivine-based positive electrode active material (LFP or LMFP) and an electrolyte to which the additive of Chemical Formula 5-1 is added, while no additive is added to the rechargeable lithium batteries of Comparative Examples 1 and 2.

[0203] In addition, since the high-temperature DC-IR increase rate of the rechargeable lithium battery of embodiment 1 is smaller than that of the rechargeable lithium battery of comparative example 1, and since the high-temperature DC-IR increase rate of the rechargeable lithium battery of embodiment 11 is smaller than that of the rechargeable lithium battery of comparative example 2, it can be determined that when the electrolyte including the additive of Chemical Formula 5-1 is used, the increase in high-temperature resistance is significantly suppressed.

[0204] Referring back to Table 4, it can be determined that the high-temperature capacity retention rate of each of the rechargeable lithium batteries of Embodiments 1 and 11 is greater than the high-temperature capacity retention rate of the rechargeable lithium batteries of Comparative Examples 3 and 4. Each of the rechargeable lithium batteries of Embodiments 1 and 11 uses an olivine-based positive electrode active material (LFP or LMFP) and an electrolyte including the additive of Chemical Formula 5-1, and each of the rechargeable lithium batteries of Comparative Examples 3 and 4 uses a nickel-based positive electrode active material (NCA or NCM) and an electrolyte including the additive of Chemical Formula 5-1.

[0205] Furthermore, since the high-temperature DC-IR increase rate of each of the rechargeable lithium batteries of Embodiments 1 and 11 was less than that of the rechargeable lithium batteries of Comparative Examples 3 and 4, it can be determined that each of Embodiments 1 and 11 has a more excellent effect of suppressing the increase in high-temperature resistance. Accordingly, when the additive of the present disclosure is used with an olivine-based positive electrode active material, it can maximize or increase the improvement in the high-temperature lifespan and high-temperature storage characteristics of the rechargeable lithium battery.

[0206] In the rechargeable lithium battery according to one or more embodiments, lifespan characteristics may be improved, and an increase in battery resistance may be suppressed or reduced under high-temperature storage.

[0207] In the present disclosure, expressions such as "at least one of," "one of," and "selected from," when preceding / following a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, "at least one of a, b, and c," "at least one selected from a, b, and c," and "at least one selected from a through c," etc., may refer to only a, only b, only c, both a and b (e.g., simultaneously), both a and c (e.g., simultaneously), both b and c (e.g., simultaneously), all of a, b, and c, or variations thereof. As used herein, " / " may be interpreted as "and" or "or," depending on the context.

[0208] In the context of this disclosure, and unless otherwise limited, the terms "use," "using," and "used" may be considered synonymous with the terms "utilize," "utilizing," and "utilized," respectively.

[0209] In the present disclosure, the term "Group" as used herein refers to a Group of the Periodic Table of the Elements according to the International Union of Pure and Applied Chemistry ("IUPAC") Group 1 to 18 system.

[0210] As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art. As used herein, "about" or "approximately" also include the stated value and mean within an acceptable range of deviation determined by one of ordinary skill in the art taking into account the errors associated with the stated measurements and with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0211] Any numerical range set forth in this article is intended to include all subranges of the same numerical precision included in the set forth range. For example, the range of "1.0 to 10.0" is intended to include all subranges between the minimum value 1.0 set forth and the maximum value 10.0 (including 1.0 and 10.0) set forth, that is, with a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit set forth in this article is intended to include all lower numerical limits contained therein, and any minimum numerical limit set forth in this disclosure is intended to include all higher numerical limits contained therein. Accordingly, the applicant reserves the right to amend this disclosure (including the claims) to explicitly set forth any subrange contained within the range explicitly set forth herein.

[0212] The battery management system (BMS) device and / or any other related devices or components according to the embodiments of the present disclosure described herein can be implemented using any appropriate hardware, firmware (e.g., an application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of the device can be formed on a single integrated circuit (IC) chip or on separate IC chips. Further, the various components of the device can be implemented on a flexible printed circuit film, a tape carrier package (TCP), or a printed circuit board (PCB), or formed on a single substrate. Further, the various components of the device can be processes or threads running on one or more processors in one or more computing devices, which execute computer program instructions and interact with other system components to perform the various functions described herein. The computer program instructions are stored in a memory, which can be implemented in a computing device using standard memory devices, such as, for example, random access memory (RAM). The computer program instructions can also be stored in other non-transitory computer-readable media, such as, for example, a CD-ROM, a flash drive, etc. Moreover, those skilled in the art will recognize that the functions of various computing devices can be combined or integrated into a single computing device, or the functions of a particular computing device can be distributed across one or more other computing devices without departing from the scope of the present disclosure.

[0213] In view of the overall disclosure, those skilled in the art will recognize that each appropriate feature of the various embodiments of the present disclosure may be combined in part or in whole or in combination with each other, and may be technically interlocked and operated in various appropriate ways, and each embodiment may be implemented independently of each other or in combination with each other in any appropriate manner, unless otherwise stated or implied.

[0214] Although the present disclosure has been described in conjunction with what are presently considered to be example embodiments, it should be understood that the disclosure is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the claims and their equivalents. Therefore, the foregoing embodiments are to be understood as examples and not limiting the present disclosure in any way.

Claims

1. A rechargeable lithium battery comprising: a positive electrode, including a positive electrode active material; a negative electrode, including a negative electrode active material; and electrolytes, wherein the electrolyte includes a nitrile additive, and wherein the positive electrode active material comprises at least one compound selected from the group consisting of compounds represented by Chemical Formula 1 and Chemical Formula 2, Chemical formula 1 Li a1 Fe x1 B 1 y1 PO 4-b1 , In Chemical Formula 1, 0.8≤a1≤1.2, 0.9≤x1≤1.1, 0≤y1≤0.05, and 0≤b1≤0.05, Chemical formula 2 Li a2 Mr z2 Feb x2 B 1 y2 NIGHT 4-b2 , In Chemical Formula 2, 0.8≤a2≤1.2, 0.5≤z2≤0.9, 0.1≤x2≤0.5, 0≤y2≤0.05, 0≤b2≤0.05, and 0.9≤z2+x2≤1.2, and In Chemical Formula 1 and Chemical Formula 2, B 1 It is at least one element selected from Ti, Mg, V and Nb.

2. The rechargeable lithium battery of claim 1, wherein B 1 For Ti.

3. The rechargeable lithium battery of claim 1, wherein the nitrile additive comprises at least one compound selected from the group consisting of: Chemical formula 3 R——C≡N, In Chemical Formula 3, R is a substituted or unsubstituted C1-C10 alkyl group, Chemical formula 4 In Chemical Formula 4, k is an integer selected from 0 to 10, and Chemical formula 5 In Chemical Formula 5, l, m, and n are each independently an integer selected from 0 to 10, The substitution refers to that at least one hydrogen of the substituent or compound is replaced by deuterium, halogen, hydroxyl, amino, C1-C30 amine, nitro, C1-C40 silyl, C1-C30 alkyl, C1-C10 alkylsilyl, C6-C30 arylsilyl, C3-C30 cycloalkyl, C3-C30 heterocycloalkyl, C6-C30 aryl, C2-C30 heteroaryl, C1-C20 alkoxy, C1-C10 fluoroalkyl, cyano and combinations thereof.

4. The rechargeable lithium battery of claim 3, wherein l, m, and n are integers different from each other. 5 . The rechargeable lithium battery of claim 1 , wherein the nitrile additive comprises at least one selected from 1,3,6-hexanetrinitrile and 1,2,6-hexanetrinitrile. 6 . The rechargeable lithium battery of claim 1 , wherein the amount of the nitrile additive is 0.01 wt % to 5 wt % relative to 100 wt % of the total weight of the electrolyte. 7 . The rechargeable lithium battery of claim 1 , wherein the electrolyte further comprises a non-aqueous organic solvent and a lithium salt. 8 . The rechargeable lithium battery of claim 7 , wherein the non-aqueous organic solvent comprises a carbonate-based solvent. 9 . The rechargeable lithium battery of claim 8 , wherein the carbonate-based solvent comprises ethylene carbonate, ethylmethyl carbonate, and dimethyl carbonate.

10. The rechargeable lithium battery of claim 9, wherein the volume ratio of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate is 1:a:b, Where a is 1 to 3, and Where b is 1 to 5.

11. The rechargeable lithium battery of claim 7, wherein the lithium salt is LiPF6.

12. The rechargeable lithium battery of claim 7, wherein the concentration of the lithium salt ranges from 0.1M to 2.0M. 13 . The rechargeable lithium battery of claim 1 , wherein the negative electrode active material comprises a carbon-based negative electrode active material, a Si-based negative electrode active material, a Sn-based negative electrode active material, or a combination thereof. 14 . The rechargeable lithium battery of claim 1 , wherein the negative electrode further comprises a solid electrolyte interface layer on a surface of the negative electrode.

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