Electrolyte for rechargeable lithium battery and rechargeable battery including same

Abstract

The present application provides an electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the same. The electrolyte includes: a non-aqueous organic solvent; a lithium salt; a first additive represented by Chemical Formula 1; and a second additive represented by Chemical Formula 2. Chemical formula 1 # imgabs0 # and chemical formula 2 # imgabs1 #

Description

Technical Field

[0001] According to one or more embodiments, the present disclosure relates to an electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the same. Background Art

[0002] Rechargeable lithium batteries are rechargeable and have up to three or more times (higher) energy density per unit weight than comparable lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. Rechargeable lithium batteries can also be charged at relatively high rates and, therefore, are commercially manufactured for use in laptop computers, cellular phones, power tools, electric bicycles, etc., and research has been actively conducted and / or pursued to improve additional energy density.

[0003] Such a rechargeable lithium battery is manufactured by injecting an electrolyte into an electrode assembly including a positive electrode (eg, including a positive electrode active material) and a negative electrode (eg, including a negative electrode active material).

[0004] Recently, one of the developments in rechargeable lithium battery technology is to improve relatively high temperature performance characteristics. Generally speaking, rechargeable lithium batteries experience an increase in resistance at relatively high temperatures, which may increase the likelihood of fire and / or explosion. For example, in a module and / or battery pack assembly including several rechargeable lithium battery cells, excessive heat generated in one rechargeable lithium battery cell may continuously propagate to adjacent rechargeable lithium battery cells, thereby causing overheating of the entire module and / or battery pack. Summary of the invention

[0005] One or more aspects relate to an electrolyte for a rechargeable lithium battery that can inhibit or reduce fire and / or explosion of a corresponding rechargeable lithium battery cell at relatively high temperatures. In some aspects, the electrolyte can prevent or reduce temperature increases in a corresponding rechargeable lithium battery cell even if (e.g., when) a fire and / or explosion occurs or begins to occur in an adjacent rechargeable lithium battery cell.

[0006] 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.

[0007] According to one or more embodiments, an electrolyte for a rechargeable lithium battery includes: a non-aqueous organic solvent; a lithium salt; a first additive represented by Chemical Formula 1; and a second additive represented by Chemical Formula 2:

[0008] Chemical formula 1

[0009]

[0010] Chemical formula 2

[0011]

[0012] The rechargeable lithium battery of one or more embodiments can inhibit or reduce the ignition and / or explosion of the corresponding rechargeable lithium battery cells at relatively high temperatures by combining the two types (kinds) of additives disclosed herein. In some embodiments, even if (for example, when) a fire and / or explosion occurs or begins to occur in an adjacent rechargeable lithium battery cell, the rechargeable lithium battery can also prevent the temperature of the corresponding rechargeable lithium battery cell from increasing (preventing the temperature from increasing). BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram illustrating a rechargeable lithium battery according to one or more embodiments.

[0014] Reference numerals

[0015] 100: Rechargeable lithium battery

[0016] 10: Positive electrode

[0017] 20: Negative electrode

[0018] 30: Diaphragm

[0019] 40: Electrode assembly

[0020] 50: Shell

[0021] 60: Sealing member DETAILED DESCRIPTION

[0022] Hereinafter, a rechargeable lithium battery according to one or more embodiments will be described in more detail with reference to the attached drawings so that those of ordinary skill in the art can easily implement them. Examples of embodiments are illustrated and described with reference to the attached drawings to explain aspects of this specification. However, these embodiments are only examples, and the present disclosure is not limited thereto. On the contrary, the present disclosure can be embodied in many different forms and is limited by the scope of the claims.

[0023] The terms used herein are for describing embodiments only and are not intended to limit the present disclosure. The singular expressions "a," "an," and "the" include plural expressions (including "at least one") unless the context clearly indicates otherwise.

[0024] As used herein, "combinations thereof" refers to mixtures, laminates, composites, copolymers, alloys, blends, reaction products, and the like of components.

[0025] In this document, it should be understood that terms such as “comprises,” “comprise,” “comprising,” “includes,” “including,” “include,” “having,” “has,” and / or “have” are intended to mark the existence of specified aspects, quantities, operations, elements, and / or any appropriate combination thereof, but do not exclude the possibility of the existence or addition of one or more other features, quantities, operations, elements, and / or any appropriate combination thereof.

[0026] In the accompanying drawings, the thickness of layers, films, panels, regions, etc. are exaggerated for clarity, wherein the same reference numerals represent the same elements, and a repeated description thereof may not be provided throughout the specification. It will be understood that if (for example, when) an element (such as a layer, film, region, or substrate) is referred to as being "on" another element (such as a layer, film, region, or substrate), it may be directly on the other element (such as a layer, film, region, or substrate), or there may also be intervening elements. In contrast, if (for example, when) an element (such as a layer, film, region, or substrate) is referred to as being directly "on" another element (such as a layer, film, region, or substrate), there are no intervening elements.

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

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

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

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

[0031] The terms used in this article are only used for the purpose of describing a particular embodiment and are not intended to limit the present disclosure. Unless otherwise defined, all terms used in the present disclosure (including chemical, technical and scientific terms) are the same as those commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the meaning in the context of the relevant field and the present disclosure, and will not be interpreted in an ideal or overly formal sense.

[0032] Example embodiments are described herein with reference to schematic diagrams of ideal embodiments. As such, variations in the shapes illustrated can be expected due to, for example, manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the zones illustrated herein, but rather include deviations in shape, for example, caused by manufacturing. For example, a zone illustrated or described as flat may typically have rough and / or nonlinear features. Moreover, illustrated sharp angles may be rounded. Therefore, the zones illustrated in the accompanying drawings are schematic in nature, and their shapes are not intended to illustrate the precise shape of the zones, and are not intended to limit the scope of the claims.

[0033] The term "may" will be understood to refer to "one or more embodiments of the present disclosure," some of which include the described elements and some of which do not include the elements and / or include alternative elements. Similarly, optional language such as "or" refers to "one or more embodiments of the present disclosure" that each include the corresponding listed items.

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

[0035] Further, in this specification, the phrase "on a plane" or "plan view" means observing a target portion from the top, and the phrase "in a cross section" means observing a cross section formed by vertically cutting the target portion from the side.

[0036] definition

[0037] The term "particle size" as used herein refers to the average diameter of the particles if (e.g., when) the particles are spherical, and refers to the average major axis length of the particles if (e.g., when) the particles are non-spherical. For example, the average particle size can be measured by a method well suited to those skilled in the art, for example, by a particle size analyzer, or by a transmission electron microscope image or a scanning electron microscope image. The average particle size value can be obtained by measuring using a dynamic light scattering method, performing data analysis, calculating the number of particles in each particle size range and calculating therefrom. Unless otherwise specified, the average particle size (D 50 ) may refer to the diameter of particles whose cumulative volume is 50% by volume in a particle size distribution. If (for example, when) measurement is performed by laser diffraction, more specifically, the particles to be measured are dispersed in a dispersion medium, and then introduced into a laser diffraction particle size measuring device of the related art (for example, MT 3000 available from Microtrac, Ltd.) using ultrasonic waves of about 28 kHz, and after irradiation at an output of 60 W, the average particle diameter (D ) based on 50% of the particle size distribution in the measuring device can be calculated. 50 As used herein, if (for example, when) a definition is provided otherwise, the average particle size (D 50 ) refers to the diameter of particles accounting for 50% by volume of the cumulative volume in a particle size distribution obtained by randomly measuring the sizes (diameters or major axis lengths) of about 20 particles in a scanning electron microscope image.

[0038] In the present disclosure, "does not include one or any 'component'", "excludes one or any 'component'", "does not contain 'component'", etc. means that the 'component' is not added, selected or used as a component in the composition / structure, but due to other impurities and / or external factors, less than an appropriate amount of the 'component' may still be included.

[0039] In this document, “or” is not interpreted as being exclusive. For example, “A or B” is interpreted as including A, B, A+B, etc.

[0040] The term "metal" is interpreted as a concept including common metals, transition metals, and metalloids (semimetals).

[0041] As used herein, if (for example, when) a specific definition is otherwise provided, "substituted" refers to the replacement of at least one hydrogen of a compound by a halide (F, Cl, Br or I), a hydroxyl group, a C1-C20 alkoxy group, a nitro group, a cyano group, an amine group, an imino group, an azido group, an amidino group, a hydrazine group, a hydrazone group, a carbonyl group, a carbamoyl group, a thiol group, an ester group, an ether group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphate group or a salt thereof, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C6-C30 aryl group, a C3-C20 cycloalkyl group, a C3-C20 cycloalkenyl group, a C3-C20 cycloalkynyl group, a C2-C20 heterocycloalkyl group, a C2-C20 heterocycloalkenyl group, a C2-C20 heterocycloalkynyl group and / or combinations thereof (for example, any suitable combination).

[0042] As used herein, "heterocycloalkyl", "heterocycloalkenyl" and "heterocycloalkynyl" refer to the presence of at least one N, O, S or P in the cycloalkyl, cycloalkenyl and cycloalkynyl ring compounds, if (for example, when) a specific definition is otherwise provided.

[0043] In the chemical formulae in the present specification, unless a specific definition is otherwise provided, hydrogen is bonded to a position where a chemical bond is not drawn if (eg, when) a chemical bond should be given.

[0044] As used herein, if (eg, when) a definition is otherwise provided, "*" refers to a connecting moiety between atoms or chemical formulae that are the same or different.

[0045] Electrolytes

[0046] Some embodiments provide an electrolyte for a rechargeable lithium battery, the electrolyte including: a non-aqueous organic solvent; a lithium salt; a first additive represented by Chemical Formula 1; and a second additive represented by Chemical Formula 2:

[0047] Chemical formula 1

[0048]

[0049] Chemical formula 2

[0050]

[0051] The first additive has an aspect of gelling the electrolyte at relatively high temperatures. The second additive has an aspect of delaying structural collapse of the positive electrode surface at relatively high temperatures by binding (eg, as a ligand) to the positive electrode transition metal oxide.

[0052] In general, the combination of the two types (kinds) of additives described herein has the aspect of rapidly increasing the viscosity of the electrolyte (e.g., at relatively high temperatures) and, at the same time, significantly reducing the ionic conductivity. For example, the combined properties can thus disconnect (e.g., shut down) a rechargeable lithium battery cell (e.g., from the surrounding environment, such as other rechargeable lithium battery cells).

[0053] Accordingly, a rechargeable lithium battery using or applying the electrolyte for a rechargeable lithium battery of one or more embodiments can suppress or reduce the ignition and / or explosion of the rechargeable lithium battery cells at relatively high temperatures by combining the two types (kinds) of additives described herein, and even if (for example, when) a fire and / or explosion starts in an adjacent rechargeable lithium battery cell, the temperature increase in the rechargeable lithium battery cell can be prevented or reduced.

[0054] Hereinafter, an electrolyte for a rechargeable lithium battery according to one or more embodiments will be described in more detail.

[0055] First Additive

[0056] A description of Chemical Formula 1 representing the first additive is as follows.

[0057] X 1 ~X 3 are each N or CH, provided that (for example, is selected from) X 1 ~X 3 At least one of them is N.

[0058] In one or more embodiments, X 1 ~X 3 They may each (eg, both) be N.

[0059] L 1 ~L 3 Each independently may be a single bond or a substituted or unsubstituted C1-C10 alkylene group.

[0060] In one or more embodiments, L 1 ~L 3 Each independently may be a substituted or unsubstituted C1-C5 alkylene group.

[0061] R 1 ~R 3 may be independently a C1-C10 epoxy group or a substituted or unsubstituted C1-C10 alkyl group, provided that (for example, selected from) R 1 ~R 3 At least one of them is a C1-C5 epoxy group.

[0062] In one or more embodiments, R 1 ~R3 Each (eg, both) may be an epoxy group.

[0063] In one or more embodiments, the first additive (eg, Chemical Formula 1) may be represented by Chemical Formula 1-1:

[0064] Chemical formula 1-1

[0065]

[0066] In Chemical Formula 1-1,

[0067] L 1 ~L 3 Each independently may be a substituted or unsubstituted C1-C5 alkylene group.

[0068] Representative examples of the first additive are as follows:

[0069] Chemical formula 1-1-1

[0070]

[0071] Chemical formula 1-1-2

[0072]

[0073] Second additive

[0074] A description of Chemical Formula 2 representing the second additive is as follows.

[0075] Y 1 and Y 2 can be independently halogen or -OL 4 -R 4 , provided that (e.g., selected from) Y 1 and Y 2 At least one of them is -OL 4 -R 4 .

[0076] L 4 It may be a single bond or a substituted or unsubstituted C1-C10 alkylene group.

[0077] R 4 It can be cyano (-CN), difluorophosphite (-OPF 2 ), substituted or unsubstituted C1~C10 alkyl, substituted or unsubstituted C2~C10 alkenyl, substituted or unsubstituted C3~C10 cycloalkyl, substituted or unsubstituted C3~C10 cycloalkenyl, substituted or unsubstituted C2~C10 alkynyl, substituted or unsubstituted C3~C10 cycloalkynyl or substituted or unsubstituted C6~C20 aryl.

[0078] If (for example, when) Y 1 and Y 2 At the same time (eg, synchronously) is -OL 4 -R 4 When two R 4 Can be unconnected (eg, exist independently), or two R 4 They may be linked to form (or provide) a substituted or unsubstituted C3-C20 monocyclic or polycyclic aliphatic heterocycle or a substituted or unsubstituted C2-C20 monocyclic or polycyclic aromatic heterocycle.

[0079] In one or more embodiments, selected from Y 1 and Y 2 One of the 1 or Y 2 ) may be a fluoro group and is selected from Y 1 and Y 2 Another one in (for example, Y 1 or Y 2 ) can be -OL 5 -R 5 ; where L 5 may be a single bond or a substituted or unsubstituted C1-C10 alkylene group; and R 5 It can be a cyano group (-CN) or a difluorophosphite group (-OPF 2 ).

[0080] In one or more embodiments, Y 1 Can be-OL 6 -R 6 And Y 2 Can be OL 7 -R 7 ; where L 6 and L 7 R may be independently a single bond or a substituted or unsubstituted C1-C10 alkylene group; 6 and R 7 may be independently substituted or unsubstituted C1-C10 alkyl, and R 6 and R 7 They may be linked to form (or provide) a substituted or unsubstituted C3-C20 monocyclic or polycyclic aliphatic heterocyclic ring.

[0081] In one or more embodiments, the second additive (eg, Chemical Formula 2) may be represented by Chemical Formula 2-1 or Chemical Formula 2-2:

[0082] Chemical formula 2-1

[0083]

[0084] Among them, in chemical formula 2-1,

[0085] m may be an integer from 1 to 5; and

[0086] R 5 It can be a cyano group (-CN) or a difluorophosphite group (-OPF 2 ).

[0087] Chemical formula 2-2

[0088]

[0089] Among them, in chemical formula 2-2,

[0090] L 6 It may be a substituted or unsubstituted C2-C5 alkylene group.

[0091] In one or more embodiments, the second additive (eg, Chemical Formula 2-2) may be represented by Chemical Formula 2-2a or Chemical Formula 2-2b:

[0092] Chemical formula 2-2a

[0093]

[0094] Chemical formula 2-2b

[0095]

[0096] Among them, in Chemical Formula 2-2a and Chemical Formula 2-2b,

[0097] R 8 ~R 17 They may each independently be a hydrogen atom, a halogen group, or a substituted or unsubstituted C1-C5 alkyl group.

[0098] Representative examples of the second additive are as follows:

[0099] Chemical formula 2-1a-1

[0100]

[0101] Chemical formula 2-1a-2

[0102]

[0103] Chemical formula 2-2a-1

[0104]

[0105] Chemical formula 2-2a-2

[0106]

[0107] Content of the first additive and the second additive

[0108] In one or more embodiments, a weight ratio of the first additive to the second additive may be about 2:1 to about 100:1, or about 3.5:1 to about 70:1.

[0109] In one or more embodiments, the sum of the first additive and the second additive may be included in an amount of about 5 wt % to about 30 wt %, or about 7.1 wt % to about 21 wt %, based on the total amount of the electrolyte.

[0110] In one or more embodiments, the first additive may be included in an amount of about 5 wt % to about 20 wt % based on the total amount of the electrolyte. In addition, in one or more embodiments, the second additive may be included in an amount of about 0.1 wt % to about 2 wt % based on the total amount of the electrolyte.

[0111] Within the disclosed scope, there may be synergistic aspects due to the combination of the two types (classes) of additives described herein.

[0112] Non-aqueous organic solvents

[0113] The nonaqueous organic solvent serves as a medium for transporting ions participating in the electrochemical reaction of the battery.

[0114] The non-aqueous organic solvent may include carbonates, esters, ethers, ketones, alcohols, aprotic solvents, and / or combinations thereof (eg, any suitable combination).

[0115] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. Ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonate lactone, valerolactone, caprolactone, etc. Ether solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. Ketone solvents may include cyclohexanone, etc. Alcohol solvents may include ethanol, isopropanol, etc., and aprotic solvents may include nitriles (such as R-CN, wherein R is a C2-C20 straight chain hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group, 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), sulfolane, etc.

[0116] The nonaqueous organic solvent may be used alone or in a mixture, and if (eg, when) used in a mixture, the mixing ratio may be suitably or appropriately adjusted according to desired or appropriate battery performance, as is well known to those skilled in the art.

[0117] In addition, if (for example, when) a carbonate-based solvent is used, a cyclic carbonate and a chain carbonate may be mixed and used. For example, the cyclic carbonate and the chain carbonate may be mixed in a volume ratio of about 1:1 to about 1:9.

[0118] The non-aqueous organic solvent may further include an aromatic hydrocarbon organic solvent. For example, a carbonate-based solvent and an aromatic hydrocarbon organic solvent may be mixed and used in a volume ratio of about 1:1 to about 30:1.

[0119] The electrolyte may further include ethylene carbonate, vinylene carbonate or ethylene carbonate-based compounds to improve the battery cycle life.

[0120] Representative examples of the ethylene carbonate-based compounds may include fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, and the like.

[0121] Lithium salts

[0122] The lithium salt is dissolved in the organic solvent, supplies lithium ions to the battery, ensures the basic operation of the rechargeable lithium battery, and improves the transport of lithium ions between the positive electrode and the negative electrode. Examples of the lithium salt may include a selected from LiPF 6 , LiBF 4 、LiSbF 6 、LiAsF 6 、LiClO 4 、LiAlO 2 、LiAlCl 4 、LiPO 2 F 2 、LiCl、LiI、LiN(SO 3 C 2 F 5 ) 2 、Li(FSO 2 ) 2 N(Lithium bis(fluorosulfonyl)imide, LiFSI), LiC 4 F 9 SO 3 、LiN(C x F 2x+1 SO 2 )(C y F 2y+1 SO 2)(x and y are integers ranging from 1 to 20), at least one of lithium tetrafluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFOB) and lithium bis(oxalato)borate (LiBOB).

[0123] The concentration of the lithium salt may be used in the range of about 0.1 M to about 2.0 M. If (for example, when) the concentration of the lithium salt is within the described range, the electrolyte has suitable or appropriate conductivity and viscosity, and thus may exhibit excellent or appropriate electrolyte performance, and lithium ions may be efficiently moved.

[0124] Rechargeable lithium battery

[0125] In one or more embodiments, a rechargeable lithium battery includes a positive electrode; a negative electrode; and an electrolyte according to one or more of the foregoing embodiments.

[0126] The rechargeable lithium battery of one or more embodiments includes the additive of the aforementioned embodiments, or the electrolyte of the aforementioned embodiments, thereby inhibiting or reducing the ignition and / or explosion of the corresponding rechargeable lithium battery cells at relatively high temperatures, and preventing or reducing the temperature increase in the corresponding rechargeable lithium battery cells even when (for example, when) a fire and / or explosion starts in an adjacent rechargeable lithium battery cell.

[0127] Hereinafter, a description overlapping with the aforementioned disclosure will not be provided, and the rechargeable lithium battery will be described in more detail.

[0128] Positive electrode active material

[0129] The positive electrode active material may be a compound capable of reversibly inserting and extracting lithium (lithiated insertion compound). For example, a composite oxide of lithium and one or more types (species) of metals selected from cobalt, manganese, nickel and / or a combination thereof (e.g., any appropriate combination) may be used.

[0130] The composite oxide may be a lithium transition metal composite oxide, and specific examples may include lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds, cobalt-free lithium nickel manganese-based oxides and / or combinations thereof (e.g., any appropriate combination).

[0131] As an example, the positive electrode active material may be a relatively high nickel-based positive electrode active material having a nickel content (e.g., amount) of about 80 mol% or more based on 100 mol% of the metal other than lithium in the lithium transition metal composite oxide. Based on 100 mol% of the metal other than lithium, the nickel content (e.g., amount) in the relatively high nickel-based positive electrode active material may be about 85 mol% or more, about 90 mol% or more, about 91 mol% or more, or about 94 mol% or more and about 99 mol% or less. High nickel-based positive electrode active materials can achieve relatively high capacity and can be applied to relatively high capacity, relatively high density rechargeable lithium batteries.

[0132] As a more specific example, a compound represented by any of the following chemical formulae may be used. 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 O 2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NeG b O 2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O 2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O 2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 2 G b O 4 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO 4 (0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe 2 (PO 4 ) 3 (0≤f≤2);Li a FePO 4 (0.90≤a≤1.8)

[0133] In the aforementioned chemical formula, A is Ni, Co, Mn and / or a combination thereof (e.g., any suitable combination); X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element and / or a combination thereof (e.g., any suitable combination); D is O, F, S, P and / or a combination thereof (e.g., any suitable combination); G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V and / or a combination thereof (e.g., any suitable combination); and L 1 is Mn, Al, and / or combinations thereof (eg, any suitable combination).

[0134] Positive electrode

[0135] A positive electrode for a rechargeable lithium battery may include a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0136] The content (eg, amount) of the positive electrode active material may be about 90 wt % to about 99.5 wt % based on 100 wt % of the positive electrode active material layer.

[0137] In some example embodiments, the positive electrode active material layer may further include a binder and a conductive material. At this time, each content (eg, amount) of the binder and the conductive material may be about 0.5 wt % to about 5 wt % based on 100 wt % of the positive electrode active material layer.

[0138] The binder is used to ensure that the positive electrode active material particles are bonded to each other and also to the positive electrode active material on the positive electrode current collector. Examples of the binder may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth) acrylated styrene-butadiene rubber, epoxy resin, (meth) acrylic resin, polyester resin and nylon, but are not limited thereto.

[0139] A conductive material is used to impart conductivity to the electrode, and in the configured battery, any conductive material may be used as long as it does not cause chemical changes. Examples of conductive materials may include carbon-based materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube); metal-based materials (including copper, nickel, aluminum, silver, etc.) in the form of (or provided with) metal powder or metal fiber; conductive polymers (such as polyphenylene derivatives); and / or mixtures thereof (e.g., any appropriate mixture).

[0140] The positive electrode current collector may include an Al foil, but the present disclosure is not limited thereto.

[0141] Negative electrode active material

[0142] The negative electrode active material may be a material that reversibly intercalates / deintercalates lithium ions, lithium metal, a lithium metal alloy, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0143] The material that reversibly intercalates / deintercalates lithium ions may be a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, and / or a combination thereof (e.g., any suitable combination). Examples of crystalline carbon may include graphite (such as amorphous, flaky, sheet-like, spherical or fibrous natural graphite or artificial graphite), and examples of amorphous carbon may include soft carbon or hard carbon, mesophase pitch carbonization products, calcined coke, etc.

[0144] The lithium metal alloy may include an alloy comprising lithium and a metal selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0145] Si-based negative electrode active materials or Sn-based negative electrode active materials may be used as materials capable of doping and dedoping lithium. Si-based negative electrode active materials may include silicon, silicon-carbon composites, SiO x(0 < x ≤ 2), Si-Q alloy (where Q is an element selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements (excluding Si), Group 15 elements, Group 16 elements, transition metals, rare earth elements, and / or combinations thereof (e.g., any suitable combination), such as Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb., Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, and / or combinations thereof (e.g., any suitable combination)) and / or combinations thereof (e.g., any suitable combination). The Sn-based negative electrode active material can be Sn, SnO 2 、SnO x (0 < x < 2), Sn alloy, and / or combinations thereof (e.g., any suitable combination).

[0146] The silicon-carbon composite can be a composite of silicon and amorphous carbon. The average particle size (D 50 ) of the silicon-carbon composite particles can be, for example, about 0.5 micrometers (μm) to about 20 μm. According to some example embodiments, the silicon-carbon composite can be in the form of (or provide) silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it can include secondary particles (cores) in which silicon primary particles are assembled (aggregated) and an amorphous carbon coating (shell) on the surface of the secondary particles. Amorphous carbon can also be disposed between the silicon primary particles, and for example, the silicon primary particles can be coated with amorphous carbon. The secondary particles can be dispersed (present) in the amorphous carbon matrix.

[0147] The silicon-carbon composite can further include crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles and amorphous carbon coated on the surface of the core. The crystalline carbon can be artificial graphite, natural graphite, and / or combinations thereof (e.g., any suitable combination). The amorphous carbon can include soft carbon or hard carbon, mesophase pitch carbonized products, and calcined coke.

[0148] If (e.g., when) the silicon-carbon composite includes silicon and amorphous carbon, based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of silicon can be about 10 wt% to about 50 wt%, and the content (e.g., amount) of amorphous carbon can be about 50 wt% to about 90 wt%. In one or more embodiments, if (e.g., when) the composite includes silicon, amorphous carbon, and crystalline carbon, based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of silicon can be about 10 wt% to about 50 wt%, and the content (e.g., amount) of crystalline carbon can be about 10 wt% to about 70 wt%, and the content (e.g., amount) of amorphous carbon can be about 20 wt% to about 40 wt%.

[0149] In addition, the thickness of the amorphous carbon coating can be about 5 nanometers (nm) to about 100 nm. The average particle size (D 50 ) of the silicon particles (primary particles) can be about 10 nm to about 1 μm or about 10 nm to about 200 nm. The silicon particles can exist in the form of elemental silicon, as (or provided as) a silicon alloy, or in an oxidized form of silicon. The oxidized form of silicon can be represented by SiO x (0 < x ≤ 2). At this time, the atomic content (e.g., amount) ratio of Si:O indicating the degree of oxidation can be about 99:1 to about 33:67. In this specification, as used herein, if (e.g., when) no other definition is provided otherwise, the average particle size (D 50 ) indicates the diameter of the particles with a cumulative volume of about 50 vol% in the particle size distribution.

[0150] The Si-based negative electrode active material or the Sn-based negative electrode active material can be used by mixing with a carbon-based negative electrode active material. If (e.g., when) a mixture of the Si-based negative electrode active material or the Sn-based negative electrode active material and the carbon-based negative electrode active material is used, the mixing ratio can be about 1:99 to about 90:10 by weight.

[0151] Negative electrode

[0152] The negative electrode for a rechargeable lithium battery includes a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder and / or a conductive material.

[0153] Based on 100 wt% of the negative electrode active material layer, the content (e.g., amount) of the negative electrode active material can be about 95 wt% to about 99.5 wt%. Based on 100 wt% of the negative electrode active material layer, the content (e.g., amount) of the binder can be about 0.5 wt% to about 5 wt%. Based on 100 wt% of the negative electrode active material layer, the content (e.g., amount) of the binder can be about 0.5 wt% to about 5 wt%. For example, the negative electrode active material layer can include about 90 wt% to about 99 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and about 0.5 wt% to about 5 wt% of the conductive material.

[0154] The binder is used to bond the negative electrode active material particles to each other and also helps to bond the negative electrode active material to the negative electrode current collector. The binder can be a non-aqueous binder, an aqueous binder, a dry binder, and / or a combination thereof (e.g., any suitable combination).

[0155] 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).

[0156] The aqueous binder may be (for example, may be selected from) styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol and / or combinations thereof (for example, any suitable combination).

[0157] If (for example, when) an aqueous binder is used as a negative electrode binder, it may further include a cellulose compound capable of imparting viscosity. As the cellulose compound, one or more types (species) of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose or an alkali metal salt thereof may be used. The alkali metal may be Na, K or Li.

[0158] The dry binder may be a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and / or combinations thereof (eg, any appropriate combination).

[0159] Conductive materials are used to impart conductivity to the electrodes, and in the configured battery, any conductive material may be used as long as it does not cause chemical changes. Specific examples may include carbon-based materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.); metal-based materials (including copper, nickel, aluminum, silver, etc.) in the form of metal powder or metal fiber (provided); conductive polymers (such as polyphenylene derivatives); and / or mixtures thereof (e.g., any appropriate mixture).

[0160] The negative electrode current collector may be (eg, may be selected from) copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and / or combinations thereof (eg, any appropriate combination).

[0161] Diaphragm

[0162] According to the type or kind of the rechargeable lithium battery, the rechargeable lithium battery may further include a separator between the negative electrode and the positive electrode. Such a separator may be, for example, a polyethylene separator, a polypropylene separator, a polyvinylidene fluoride separator, and multilayers thereof (such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, and a polypropylene / polyethylene / polypropylene three-layer separator).

[0163] The separator may include a porous substrate and a coating including an organic material, an inorganic material, and / or a combination thereof (eg, any suitable combination) on (eg, one or both surfaces or sides (eg, opposing surfaces)) the porous substrate.

[0164] The porous substrate may be a polymer film formed from any one selected from the following: polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyether ketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, fiberglass, Teflon and polytetrafluoroethylene, or copolymers and / or mixtures (e.g., any suitable mixtures) of two or more thereof.

[0165] The porous substrate may have a thickness of about 1 μm to about 40 μm, for example, about 1 μm to about 30 μm, about 1 μm to about 20 μm, about 5 μm to about 15 μm, or about 10 μm to about 15 μm.

[0166] The organic material may include a (meth)acrylic copolymer including a first structural unit derived from (meth)acrylamide and a second structural unit including at least one of a structural unit derived from (meth)acrylic acid or (meth)acrylate and a structural unit derived from (meth)acrylamide sulfonic acid or a salt thereof.

[0167] The inorganic material may include a 2 O 3 、SiO 2 、TiO 2 SnO 2 、CeO 2 , MgO, NiO, CaO, GaO, ZnO, ZrO 2 , Y 2 O 3 、SrTiO 3 、BaTiO 3 Mg(OH) 2 , boehmite and / or a combination thereof (eg, any suitable combination), but the present disclosure is not limited thereto. The average particle size (D50 ) may be from about 1 nm to about 2000 nm, for example, from about 100 nm to about 1000 nm or from about 100 nm to about 700 nm.

[0168] The organic material and the inorganic material may be mixed in one coating layer, or may be present (or provided) in the form of a stack of a coating layer including an organic material and a coating layer including an inorganic material.

[0169] The coating layer may have a thickness of about 0.5 μm to about 20 μm, for example, about 1 μm to about 10 μm or about 1 μm to about 5 μm.

[0170] Rechargeable lithium battery

[0171] The rechargeable lithium battery may be classified into a cylindrical battery, a prismatic battery, a pouch type battery, a coin type battery, etc., depending on the shape of the rechargeable lithium battery. Figure 1 Schematic diagram showing a rechargeable lithium battery according to some example embodiments. Figure 1 , the rechargeable lithium battery 100 includes an electrode assembly 40 and a case 50 accommodating the electrode assembly 40, and the electrode assembly 40 includes a separator 30 interposed between a positive electrode 10 and a negative electrode 20. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte. Figure 1 As shown in FIG. 1 , the rechargeable lithium battery 100 may include a sealing member 60 that seals the case 50 .

[0172] Terms such as "substantially," "about," and "approximately" are used as relative terms rather than terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art. They may include the stated value and an acceptable range of deviation determined by one of ordinary skill in the art taking into account the limitations and errors associated with the measurement of that quantity. For example, "about" may refer to one or more standard deviations, or ±30%, 20%, 10%, or 5% of the stated value.

[0173] The numerical ranges disclosed herein include and are intended to disclose all sub-ranges of the same numerical precision. For example, the range of "1.0 to 10.0" includes all sub-ranges 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. Therefore, the applicant reserves the right to amend this specification (including the claims) to explicitly set forth any sub-ranges contained within the range explicitly set forth herein.

[0174] Hereinafter, examples and comparative examples of the present disclosure will be described. However, the present disclosure is not limited to the following examples.

[0175] Example

[0176] Examples 1 to 8 and Comparative Examples 1 to 5

[0177] (1) Preparation of electrolyte

[0178] As the non-aqueous organic solvent, a carbonate-based solvent mixed at a volume ratio of ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) = 20:10:70 was used.

[0179] 1.5M lithium salt (LiPF 6 ) was mixed with a nonaqueous organic solvent, and additives were added according to the composition in Table 1 to obtain an electrolyte.

[0180] Chemical formula 1-1-1 (tris(2,3-epoxypropyl)isocyanurate, CAS No. 2451-62-9)

[0181]

[0182] Chemical formula 1-1-2 (1,3,5-tris[4-(2-oxiranyl)butyl]-1,3,5-triazine-2,4,6-trione, CAS No. 91403-65-5)

[0183]

[0184] Chemical formula 2-1a-1 (CAS No. 3965-00-2)

[0185]

[0186] Chemical formula 2-2a-2 (CAS No. 16415-09-1)

[0187]

[0188] (2) Manufacturing of rechargeable lithium battery cells

[0189] LiNi as the positive electrode active material 0.91 Co 0.04 Al 0.05 O 2 , polyvinylidene fluoride as a binder, and Ketjen black as a conductive material were mixed in a weight ratio of 98.5:0.75:0.75, respectively, and then dispersed in N-methylpyrrolidone to prepare a positive electrode active material slurry.

[0190] The positive electrode active material slurry was coated on a 14 micrometer (μm) thick Al foil, dried at 110° C., and pressed to manufacture a positive electrode.

[0191] A mixture including artificial graphite and silicon particles mixed in a weight ratio of 93:7 was used as a negative electrode active material, and the negative electrode active material, a styrene-butadiene rubber binder, and carboxymethyl cellulose were dispersed in distilled water in a weight ratio of 97:1:2 to prepare a negative electrode active material slurry.

[0192] The negative electrode active material slurry was coated on a 10 μm thick Cu foil, dried at 100° C., and pressed to produce a negative electrode.

[0193] The manufactured positive electrode and negative electrode were assembled with a 25 μm thick polyethylene separator to manufacture an electrode assembly, the electrode assembly was housed in a cylindrical can having a width of 21 millimeters (mm) and a length of 70 mm as a battery container, and the electrolyte of Example 1 was injected therein to manufacture a rechargeable lithium battery cell.

[0194] Table 1

[0195]

[0196] In the aforementioned electrolyte composition, "content (eg, amount) (wt %)" is based on 100 wt % of the total electrolyte (lithium salt+nonaqueous organic solvent+additives).

[0197] Evaluation Example 1: Evaluation of thermal exposure conditions

[0198] For each of the rechargeable lithium battery cells according to Examples 1 to 8 and Comparative Examples 1 to 5, heat exposure characteristics were evaluated.

[0199] The rechargeable lithium battery cell was heated from room temperature to a temperature of 139° C. or higher at a rate of 5° C. / min and then left to stand at the reached temperature for 1 hour. The reached temperature was evaluated as the “heat exposure test passing temperature”.

[0200] Table 2

[0201] Thermal exposure test passing temperature (℃) Comparative Example 1 139 Comparative Example 2 142 Comparative Example 3 142 Comparative Example 4 140 Comparative Example 5 140 Example 1 143 Example 2 143 Example 3 143 Example 4 143 Example 5 143 Example 6 143 Example 7 143 Example 8 143

[0202] Evaluation Example 2: Evaluation of High Temperature Storage

[0203] (1) Capacity retention rate and capacity recovery rate

[0204] Each of the rechargeable lithium battery cells of the embodiment and the comparative example was charged and discharged once at 0.33 C, and the charge and discharge capacity (relative high temperature storage) was measured.

[0205] Each of the rechargeable lithium battery cells of the embodiment and the comparative example was charged to SOC 100% (to achieve a charging state of 100% charging capacity based on 100% of the total charging capacity of the battery), stored at 60° C. for 30 days, and discharged to 3.0 V at a constant current of 0.33 C, and then, the initial discharge capacity was measured.

[0206] The discharge capacity was measured twice by recharging to 4.3 V at a constant current of 0.33 C and at a constant voltage with 0.02 C as a cutoff current, and discharging to 3.0 V at a constant current of 0.33 C. The ratio of the first discharge capacity to the initial discharge capacity is shown as the capacity retention rate (retention capacity), and the ratio of the second discharge capacity to the initial discharge capacity is shown as the capacity recovery rate (recovery capacity).

[0207] (2) DC resistance change rate (DCIR increase rate)

[0208] The ΔV / ΔI (voltage change / current change) of each of the rechargeable lithium battery cells of the embodiments and comparative examples was measured to obtain the initial DC internal resistance (DCIR), and then, fully charged (SOC 100%) to its internal maximum energy state, and stored at a relatively high temperature of 60°C for 30 days to measure the DCIR, which was used to calculate the DCIR increase rate (%) according to Equation 1, and the results are shown in Table 3.

[0209] Equation 1

[0210] DCIR increase rate = (DCIR after 30 days / initial DCIR) × 100

[0211] (3) Open circuit voltage change rate

[0212] Each of the rechargeable lithium battery cells of the embodiment and the comparative example was fully charged to SOC 100% at its internal maximum energy state, its open circuit voltage (OCV) was measured, and stored at a relatively high temperature (55±2°C) for 90 days. After storing the rechargeable lithium battery cells at a relatively high temperature for 90 days, its open circuit voltage was measured, and the open circuit voltage change rate was calculated according to Equation 2, and the results are shown in Table 3.

[0213] Equation 2

[0214] Open circuit voltage change rate = (open circuit voltage after x days of relatively high temperature storage / open circuit voltage at the beginning of storage)

[0215] Table 3

[0216]

[0217] Summarize

[0218] Referring to Table 2, if (for example, when) one type or kind of additive out of two types (kinds) of additives is used, the thermal exposure is increased to 142°C, but if (for example, when) the two types (kinds) of additives are combined, the thermal exposure is increased to 143°C (for example, further increased by 1°C or more).

[0219] In contrast, referring to Table 3, if (eg, when) two types (kinds) of additives are combined, the content (eg, amount) of each additive and the total content (eg, amount) of the two additives should be limited by comprehensively considering storage characteristics at relatively high temperatures.

[0220] For example, based on the total amount of the electrolyte, the first additive should be used in the range of 5wt% to 20wt%, the second additive should be used in the range of 0.1wt% to 2wt%, and the combined (e.g., all) additives should be used in the range of a total of 7.1wt% to 21wt%.

[0221] According to the battery management system (BMS) device and / or any other related device or component of the embodiments of the present invention described herein, any appropriate hardware, firmware (e.g., a dedicated integrated circuit), software, or a combination of software, firmware, and hardware may be used for implementation. For example, the various components of the device may be formed on an integrated circuit (IC) chip or on separate IC chips. Further, the various components of the device may be implemented on a flexible printed circuit film, a tape carrier package (TCP), or a printed circuit board (PCB), or formed on a substrate. Further, the various components of the device may 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 may be implemented in a computing device using a standard memory device, such as, for example, a random access memory (RAM). The computer program instructions may also be stored in other non-transitory computer-readable media, such as, for example, a CD-ROM or a flash drive, etc. Moreover, those skilled in the art will recognize that, without departing from the scope of the embodiments of the present disclosure, the functions of various computing devices may be combined or integrated into a single computing device, or the functions of a particular computing device may be distributed on one or more other computing devices.

[0222] Although the present disclosure has been described in conjunction with exemplary embodiments currently considered to be practical, it should be understood that the present disclosure is not limited to the disclosed embodiments. However, on the contrary, the present disclosure is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents.

Claims

1. An electrolyte, include: Non-aqueous organic solvents; Lithium salts; A first additive represented by Chemical Formula 1; and The second additive represented by Chemical Formula 2: Chemical formula 1 In Chemical Formula 1, X 1 ~X 3 are each N or CH and are selected from X 1 ~X 3 At least one of is N; L 1 ~L 3 Each is independently a single bond or a substituted or unsubstituted C1-C10 alkylene group; and R 1 ~R 3 Each is independently an epoxy group or a substituted or unsubstituted C1-C10 alkyl group, and is selected from R 1 ~R 3 At least one of them is an epoxy group; Chemical formula 2 In chemical formula 2, Y 1 and Y 2 Each is independently halogen or -OL 4 -R 4 , and selected from Y 1 and Y 2 At least one of them is -OL 4 -R 4 ; L 4 is a single bond or a substituted or unsubstituted C1-C10 alkylene group; R 4 is cyano, difluorophosphite, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C3-C10 cycloalkenyl, substituted or unsubstituted C2-C10 alkynyl, substituted or unsubstituted C3-C10 cycloalkynyl, or substituted or unsubstituted C6-C20 aryl; and When Y 1 and Y 2 At the same time -OL 4 -R 4 When two R 4 Not connected, or connected to form a substituted or unsubstituted C3-C20 monocyclic or polycyclic aliphatic heterocycle or a substituted or unsubstituted C2-C20 monocyclic or polycyclic aromatic heterocycle, The electrolyte is used in rechargeable lithium batteries.

2. The electrolyte according to claim 1, wherein X 1 ~X 3 Each is N.

3. The electrolyte according to claim 1, wherein L 1 ~L 3 Each is independently a substituted or unsubstituted C1-C5 alkylene group.

4. The electrolyte according to claim 1, wherein R 1 ~R 3 Each is an epoxy group.

5. The electrolyte according to claim 1, wherein The first additive is represented by chemical formula 1-1: Chemical formula 1-1 In Chemical Formula 1-1, L 1 ~L 3 Each is independently a substituted or unsubstituted C1-C5 alkylene group.

6. The electrolyte according to claim 1, wherein The first additive is selected from Chemical Formula 1-1-1 and Chemical Formula 1-1-2: Chemical formula 1-1-1 Chemical formula 1-1-2 7. The electrolyte according to claim 1, in: Selected from Y 1 and Y 2 One of them is a fluoro group and is selected from Y 1 and Y 2 The other one is -OL 5 -R 5 , L 5 is a single bond or a substituted or unsubstituted C1-C10 alkylene group, and R 5 is a cyano group or a difluorophosphite group; or Y 1 For-OL 6 -R 6 And Y 2 For OL 7 -R 7 , L 6 and L 7 Each is independently a single bond or a substituted or unsubstituted C1-C10 alkylene group, R 6 and R 7 are each independently a substituted or unsubstituted C1-C10 alkyl group, and R 6 and R 7 Connected to form a substituted or unsubstituted C3-C20 monocyclic or polycyclic aliphatic heterocyclic ring.

8. The electrolyte of claim 7, wherein The second additive is represented by Chemical Formula 2-1 or Chemical Formula 2-2: Chemical formula 2-1 In chemical formula 2-1, m is an integer from 1 to 5; and R 5 is a cyano group or a difluorophosphite group, Chemical formula 2-2 In chemical formula 2-2, L 6 It is a substituted or unsubstituted C2-C5 alkylene group.

9. The electrolyte of claim 8, wherein The second additive is represented by Chemical Formula 2-2a or Chemical Formula 2-2b: Chemical formula 2-2a Chemical formula 2-2b In Chemical Formula 2-2a and Chemical Formula 2-2b, R 8 ~R 17 Each is independently a hydrogen atom, a halogen group, or a substituted or unsubstituted C1-C5 alkyl group.

10. The electrolyte according to claim 1, wherein The second additive is one selected from the following: Chemical formula 2-1a-1 Chemical formula 2-1a-2 Chemical formula 2-2a-1 and Chemical formula 2-2a-2 11. The electrolyte according to claim 1, wherein The weight ratio of the first additive to the second additive is 2:1 to 100:

1.

12. The electrolyte of claim 1, wherein The electrolyte includes the first additive in an amount of 5 wt % to 20 wt % based on a total amount of the electrolyte.

13. The electrolyte of claim 1, wherein The electrolyte includes the second additive in an amount of 0.1 wt % to 2 wt % based on the total amount of the electrolyte.

14. The electrolyte of claim 1, wherein The non-aqueous organic solvent includes ethylene carbonate, ethylmethyl carbonate and dimethyl carbonate.

15. A rechargeable lithium battery, include: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and The electrolyte according to any one of claims 1 to 14.

16. The rechargeable lithium battery of claim 15, wherein The rechargeable lithium battery further includes a separator between the positive electrode and the negative electrode and impregnated with the electrolyte.

Images