Electrolyte for rechargeable lithium battery and rechargeable lithium battery including same

Abstract

The present disclosure relates to an electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the same. According to the present embodiment, 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 as a nitrile-based additive: Chemical Formula 1 # imgabs0 #

Description

Technical Field

[0001] One or more aspects of embodiments of the present disclosure relate 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 an energy density per unit weight at least three times higher than that of lead storage batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. Rechargeable lithium batteries can also be charged at a relatively high rate, and are therefore commercially manufactured for use in laptop computers, cellular phones, power tools, electric bicycles, electric vehicles, etc., and research on further improving energy density is being actively pursued.

[0003] Such a rechargeable lithium battery may be manufactured by injecting an electrolyte into an electrode assembly including a positive electrode including a positive electrode active material capable of intercalating / deintercalating lithium ions and a negative electrode including a negative electrode active material capable of intercalating / deintercalating lithium ions.

[0004] Recently, one of the development directions of rechargeable lithium batteries is to improve high temperature characteristics. In the related art, rechargeable lithium batteries may have problems such as increased resistance at high temperatures, fire and / or explosion. For example, when a module and / or battery pack is formed by assembling several rechargeable lithium battery cells, if (for example, when) one of the rechargeable lithium battery cells starts to catch fire and / or explode, the heat may continue to spread to its adjacent battery cells, so there is a risk that the entire module and / or battery pack may catch fire and / or explode. Summary of the invention

[0005] According to one or more aspects of the embodiments of the present disclosure, an electrolyte for a rechargeable lithium battery can inhibit or reduce the risk of fire and / or explosion of a battery cell at high temperature, and even if a fire and / or explosion starts in an adjacent battery cell, the temperature increase in the battery cell can be prevented or reduced. Additional aspects will be set forth in part in the subsequent description and in part will be obvious from the description, or can be learned by practicing the presented embodiments of the present disclosure.

[0006] According to some 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 that is a nitrile additive:

[0007] Chemical formula 1

[0008]

[0009] Some embodiments provide a rechargeable lithium battery including: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte according to the present embodiment.

[0010] The rechargeable lithium battery according to one or more embodiments of the present disclosure is able to suppress or reduce the ignition and / or explosion of battery cells at high temperatures by combining two types (kinds) of additives according to the present embodiments, and even if a fire and / or explosion occurs in an adjacent battery cell, the temperature increase of the battery cell can be prevented or reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram illustrating a rechargeable lithium battery according to some embodiments.

[0012] Figure 2 to Figure 6 Each illustrates a graph showing heat exposure evaluation results of the rechargeable lithium battery cells of Comparative Examples 1, 2, and 4 and Examples 1 and 2 if (eg, when) exposed to heat at 138° C., respectively.

[0013] Figure 7 to Figure 11 Each illustrates a graph showing heat exposure evaluation results of the rechargeable lithium battery cells of Comparative Examples 1, 2, and 4 and Examples 1 and 2 if (eg, when) exposed to heat at 141° C., respectively.

[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] 70: Electrode terminal DETAILED DESCRIPTION

[0022] Hereinafter, a rechargeable lithium battery according to some embodiments will be described in more detail with reference to the accompanying drawings. However, these embodiments are examples, and the present disclosure is not limited thereto, and the present disclosure is defined by the scope of the claims and their equivalents.

[0023] It will be understood that although the terms first, second, etc. may be used to describe various elements in this article, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, without departing from the teachings of the present invention, the first element may be referred to as the second element. Similarly, the second element may be referred to as the first element.

[0024] As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0025] It will be further understood that the terms “includes,” “including,” “comprises,” and / or “comprising,” when used in this specification, indicate the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0026] As used herein, the terms "use," "using," and "used" may be considered synonymous with the terms "utilize," "utilizing," and "utilized," respectively.

[0027] As used herein, the expression "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...", when preceding / following a list of elements, modify the entire list of elements without modifying the individual elements of the list. For example, "selected from at least one of a, b, and 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), both b and c (e.g., simultaneously), all of a, b, and c, or variations thereof.

[0028] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0029] Further, when describing embodiments of the present disclosure, the use of “may” refers to “one or more embodiments of the present disclosure.”

[0030] It will be understood that when an element is referred to as being "on," "connected to," or "coupled to" another element, it can be directly on, connected to, or coupled to the other element, or one or more intervening elements may also be present. When an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no intervening elements.

[0031] 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. "About" or "approximately" as used herein include the stated value and mean within an acceptable range of deviation determined by one of ordinary skill in the art taking into account limitations and errors associated with the measurement of that quantity (i.e., limitations of the measurement system). For example, "about" may mean within one or more standard deviations, or ±30%, ±20%, ±10%, or ±5% of the stated value.

[0032] The numerical ranges set forth herein are intended to include all subranges of the same numerical precision contained within the set forth range. For example, the range of "1.0 to 10.0" is intended to include all subranges between the set forth minimum value 1.0 and the set forth maximum value 10.0 (and including the endpoints), that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit set forth herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit set forth in this specification is intended to include all higher numerical limits contained therein. Accordingly, the applicant reserves the right to amend this specification (including claims) to explicitly set forth any subrange contained within the range explicitly set forth herein.

[0033] As used herein, if (for example, when) a specific definition is otherwise provided, "substituted" means that at least one hydrogen of the compound is replaced by a halogen atom (F, Cl, Br and / 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 amidine 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-C20 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 any appropriate combination thereof.

[0034] As used herein, "heterocycloalkyl", "heterocycloalkenyl", "heterocycloalkynyl" and "heterocycloalkylene" refer to the presence of at least one N, O, S or P in the cyclic compounds of cycloalkyl, cycloalkenyl, cycloalkynyl and cycloalkylene, if (for example, when) a specific definition is otherwise provided.

[0035] In the chemical formulae in the present specification, unless a specific definition is otherwise provided, if (for example, when) a chemical bond is not drawn at a position where a chemical bond should be given, hydrogen is bonded to the position.

[0036] As used herein, if (eg, when) no definition is otherwise provided, "*" refers to a connecting moiety (eg, a binding site) between the same or different atoms and / or chemical formulas.

[0037] Electrolyte

[0038] Some embodiments provide an electrolyte for a rechargeable lithium battery, which includes a non-aqueous organic solvent; a lithium salt; a first additive represented by Chemical Formula 1; and a second additive that is a nitrile additive:

[0039] Chemical formula 1

[0040]

[0041] Without being bound by any particular theory, based on a mechanism in which epoxy groups ring-open at an elevated temperature of about 100° C. and a substantially continuous polymerization reaction occurs between different first additives, it is believed that the first additive may have an effect of gelling the electrolyte due to the epoxy groups (e.g., may facilitate gelling the electrolyte due to the epoxy groups).

[0042] Without being bound by any particular theory, it is believed that the second additive has the effect of gelling the electrolyte at high temperatures exceeding about 138° C. due to the nitrile groups (eg, may facilitate gelling the electrolyte at high temperatures exceeding about 138° C. due to the nitrile groups).

[0043] Accordingly, compared to an electrolyte including only the first additive or only the second additive, an electrolyte including both the first additive and the second additive can quickly or appropriately increase the viscosity of the electrolyte at a high temperature exceeding about 138° C., and at the same time (e.g., synchronously), can significantly or appropriately reduce the ionic conductivity and shut down the rechargeable lithium battery cell.

[0044] Accordingly, a rechargeable lithium battery to which the electrolyte for a rechargeable lithium battery of some embodiments is applied can suppress or reduce the ignition and / or explosion of battery cells at high temperatures by combining two types (kinds) of additives of the present embodiments, and even if a fire and / or explosion starts in an adjacent battery cell, the temperature increase in the battery cell including the electrolyte can be prevented or reduced.

[0045] Hereinafter, an electrolyte for a rechargeable lithium battery according to some embodiments will be described in more detail.

[0046] First Additive

[0047] The description of Chemical Formula 1 representing the first additive is as follows:

[0048] In Chemical Formula 1, R 1 It may be C1-C10 alkyl, C3-C10 cycloalkyl, C2-C20 heterocycloalkyl containing heteroatoms of N, O, S and / or P, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C2-C10 heteroaryl containing heteroatoms of N, O, S and / or P, or *-(L 1 )-(L 2 )-R 2 .

[0049] In some embodiments, R 1 Can be *-(L 1 )-(L 2 )-R 2 ; where L 1 It can be a single bond or *-(C=O)-O-*; L 2 can be a single bond or a C1-C10 alkylene group; and R 2 It may be hydrogen or a substituent represented by chemical formula A:

[0050] Chemical formula A

[0051]

[0052] In some embodiments, Chemical Formula 1 may be represented by Chemical Formula 1-1 or Chemical Formula 1-2:

[0053] Chemical formula 1-1

[0054]

[0055] Chemical formula 1-2

[0056]

[0057] In the chemical formula 1-1 and the chemical formula 1-2, L 3 It can be a C1~C10 alkylene group.

[0058] Representative examples of the first additive are as follows:

[0059] Chemical formula 1-1-1

[0060]

[0061] Chemical formula 1-2-1

[0062]

[0063] Second additive

[0064] The second additive may include one or more types (species) of multifunctional nitrile compounds including two or more nitrile groups.

[0065] As the “polyfunctional nitrile compound including two or more nitrile groups”, the second additive may be represented by Chemical Formula 2:

[0066] Chemical formula 2

[0067] NC-(L 3 ) a -(L 4 ) b -CN,

[0068] Wherein, in Chemical Formula 2, L 3 and L 4 They may each independently be an unsubstituted C1-C10 alkyleneoxy group, an unsubstituted C1-C10 alkylene group, or a C1-C10 alkylene group substituted by a cyano group (—CN); and a and b may each independently be an integer in the range of 0-3.

[0069] In some embodiments, Chemical Formula 2 may be represented by Chemical Formula 2-1 or Chemical Formula 2-2:

[0070] Chemical formula 2-1

[0071] NC-(L 5 ) c -(L 6 ) d -CN

[0072] Chemical formula 2-2

[0073]

[0074] In Chemical Formula 2-1 and Chemical Formula 2-2, L 5 ~L 8 Each of c to f may independently represent an unsubstituted C1-C10 alkyleneoxy group or an unsubstituted C1-C10 alkylene group; and each of c to f may independently represent an integer in the range of 0 to 3.

[0075] Representative examples of the second additive are as follows:

[0076] Chemical formula 2-1-1

[0077]

[0078] Chemical formula 2-1-2

[0079]

[0080] Chemical formula 2-2-1

[0081]

[0082] Weight ratio of the first additive and the second additive

[0083] In some embodiments, the weight ratio of the first additive to the second additive may be about 1: 1 to about 20: 1. Within this range, it is believed that there is a synergistic effect due to the combination of the above two types (kinds) of additives.

[0084] In some embodiments, a weight ratio of the first additive to the second additive may be about 2:1 to about 10:1.

[0085] The content of each additive

[0086] In some embodiments, the first additive may be included in an amount of about 1 to about 20 wt % based on the total amount of the electrolyte. Within this range, the effect of the first additive may be increased.

[0087] In some embodiments, the first additive may be included in an amount of about 5 to about 10 wt % based on the total amount of the electrolyte.

[0088] In some embodiments, the second additive may be included in an amount of about 0.1 to about 10 wt % based on the total amount of the electrolyte. Within this range, the effect of the second additive may be increased.

[0089] In some embodiments, the second additive may be included in an amount of about 1 to about 5 wt % based on the total amount of the electrolyte.

[0090] Non-aqueous organic solvent

[0091] The nonaqueous organic solvent serves as a medium for transmitting ions participating in the electrochemical reaction of the battery.

[0092] The non-aqueous organic solvent may include a carbonate solvent, an ester solvent, an ether solvent, a ketone solvent, an alcohol solvent and / or an aprotic solvent.

[0093] Carbonate solvents may include ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. Ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, decanoic acid lactone, mevalonate lactone, caprolactone, etc. Ether solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, tetrahydrofuran, etc. Ketone solvents may include cyclohexanone, etc. Alcohol solvents may include ethanol, isopropanol, etc., and non-protonic 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, including a double bond, an aromatic ring or an ether group)), amides (such as dimethylformamide), dioxolanes (such as 1,3-dioxolane), cyclopentane sulfone, etc.

[0094] The non-aqueous organic solvent may be used alone or in combination of two or more thereof, and if (for example, when) used in combination of two or more thereof, the mixing ratio may be appropriately or suitably adjusted according to the desired or appropriate battery performance, which is well known to those skilled in the art.

[0095] The carbonate solvent is prepared by mixing a cyclic carbonate and a chain (eg, linear) carbonate. The cyclic carbonate and the chain carbonate are mixed together in a volume ratio of about 5:95 to about 50:50. When the mixture is used as an electrolyte, it can have enhanced performance.

[0096] In some embodiments, the non-aqueous organic solvent may include a carbonate-based solvent, an ester-based solvent, and / or any appropriate combination thereof.

[0097] In some embodiments, the non-aqueous organic solvent may include ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP) and / or propyl propionate (PP). In this case, the performance of the electrolyte may be improved.

[0098] Lithium salts

[0099] The lithium salt can be dissolved in a non-aqueous organic solvent, can supply lithium ions to the battery, can facilitate the basic operation of the rechargeable lithium battery, and can improve the transport of lithium ions between the positive electrode and the negative electrode. Examples of lithium salts may include those selected from LiPF6, LiBF4, LiDFOP, LiDFOB, LiPO2F2, LiSbF6, LiAsF6, LiN(SO2C2F5)2, Li(CF3SO2)2N, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide: LiFSI), LiC4F9SO3, LiClO4, LiAlO2, LiAlCl4, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2) (wherein x and y are natural numbers, for example, integers of 1 to 20), at least one of LiCl, LiI and LiB(C2O4)2 (lithium bis(oxalato)borate: LiBOB). The concentration of the lithium salt may be in the range of about 0.1 M to about 2.0 M. When the concentration of the lithium salt is within the above range, the electrolyte has appropriate or suitable conductivity and viscosity, and thus can exhibit excellent or suitable electrolyte performance, and lithium ions can be effectively or appropriately moved.

[0100] Rechargeable lithium battery

[0101] In some embodiments, a rechargeable lithium battery includes: a positive electrode; a negative electrode; and an electrolyte according to the present embodiment including the additive according to the present embodiment.

[0102] The rechargeable lithium battery of some embodiments includes the electrolyte of the present embodiment including the additive of the present embodiment, and can suppress or reduce the risk of fire and / or explosion of the battery cell at high temperature, and even if fire and / or explosion starts in an adjacent battery cell, the temperature increase in the battery cell can be prevented or reduced.

[0103] Hereinafter, descriptions overlapping with the above will be omitted (eg, will not be provided), and the rechargeable lithium battery will be described in more detail.

[0104] Positive electrode active material

[0105] The positive electrode active material may be a compound capable of reversibly intercalating and deintercalating lithium (lithiated intercalation compound). For example, a composite oxide of one or more types (species) of lithium and a metal selected from cobalt, manganese, nickel, and a combination thereof may be used.

[0106] The composite oxide may be a lithium transition metal composite oxide, and non-limiting examples may include lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds, cobalt-free nickel manganese-based oxides, and / or any appropriate combination thereof.

[0107] As an example, based on 100 mol% of the metal excluding lithium in the lithium transition metal composite oxide, the positive electrode active material may be a high nickel positive electrode active material having a nickel content (e.g., amount) of about 80 mol% or more. Based on 100 mol% of the metal excluding lithium, the nickel content (e.g., amount) in the high nickel 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 positive electrode active materials can achieve high or appropriately high capacity and can be applied to high capacity, high density rechargeable lithium batteries.

[0108] For example, any compound represented by the following chemical formula can be used: 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 NeG 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 Mn1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 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);Li a FePO4(0.90≤a≤1.8).

[0109] In the above chemical formula, A may be Ni, Co, Mn and / or any appropriate combination thereof; X may be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element and / or any appropriate combination thereof; D may be O, F, S, P and / or any appropriate combination thereof; G may be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V and / or any appropriate combination thereof; and L 1 It may be Mn, Al and / or any appropriate combination thereof.

[0110] For example, the positive electrode active material may include a cobalt-free lithium nickel manganese-based oxide.

[0111] As used herein, a cobalt-free lithium nickel manganese oxide as a positive electrode active material refers to a positive electrode active material composed of nickel, manganese, etc. as the main component (e.g., main component), and there is no cobalt in the composition of the positive electrode active material. As used herein, the term "main component" refers to a component (e.g., metal) present in the composition in an amount greater than any other single component in the composition (based on the total metal excluding lithium (unless otherwise defined)). In contrast, the term "basic component" refers to a component that constitutes at least 50% (wt% or at%) or more of the composition.

[0112] As an example, the cobalt-free lithium nickel manganese-based oxide may include at least one type or kind of the lithium composite oxide represented by Chemical Formula 3.

[0113] Chemical formula 3

[0114] Li a Ni x Mn y M 1 z M 2 w O 2±b X c .

[0115] In chemical formula 3,

[0116] 0.5≤a<1.8,0≤b≤0.1,0≤c≤0.1,0≤w<0.1,0.6≤x<1.0,0 <y≤0.4,0≤z≤0.1,w+x+y+z=1,

[0117] M 1 and M 2 Each of them may be independently one or more elements selected from Al, Mg, Ti, Zr, Cr, Sr, V, B, W, Mo, Nb, Si, Ba, Ca, Ce, Cr, Fe and Nb, and X may be one or more elements selected from S, F, P and Cl.

[0118] As an example, Chemical Formula 3 may be represented by Chemical Formula 3-1.

[0119] Chemical formula 3-1

[0120] Li a Ni x1 Mn y1 Al z1 M 2 w1 O 2±b X c .

[0121] In chemical formula 3-1,

[0122] 0.5≤a<1.8,0≤b≤0.1,0≤c≤0.1,0≤w1<0.1,0.6≤x1<1.0,0 <y1≤0.4,0≤z1≤0.1,w1+x1+y1+z1=1,

[0123] M 2 It may be one or more elements selected from Mg, Ti, Zr, Cr, Sr, V, B, W, Mo, Nb, Si, Ba, Ca, Ce, Cr, Fe and Nb, and X may be one or more elements selected from F, P and Cl.

[0124] In Chemical Formula 3-1, x1 may be 0.6≤x1≤0.9, y1 may be 0.1≤y1≤0.4, and z1 may be 0≤z1≤0.1, or x1 may be 0.6≤x1≤0.8, y1 may be 0.2≤y1≤0.4, and z1 may be 0≤z1≤0.1.

[0125] For example, in Chemical Formula 3-1, x1 may be 0.6≤x1≤0.79, y1 may be 0.2≤y1≤0.39, and z1 may be 0.01≤z1<0.1.

[0126] Positive electrode

[0127] 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.

[0128] 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.

[0129] In some example embodiments, the positive electrode active material layer may further include a binder and a conductive material. In this case, the content (eg, amount) of each 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.

[0130] 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 to 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.

[0131] The conductive material is used to impart conductivity to the electrode, and in the configured battery, any suitable conductive material may be used as long as it does not cause undesirable chemical changes in the battery. Examples of the conductive material may include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber and / or carbon nanotube; metal-based materials including copper, nickel, aluminum, silver, etc. in the form of metal powder and / or metal fiber; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0132] The positive electrode current collector may include an Al foil, but the present disclosure is not limited thereto.

[0133] Negative electrode active material

[0134] 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, and / or a transition metal oxide.

[0135] Materials capable of reversibly embedding / desorbing lithium ions can be carbon-based negative electrode active materials, such as crystalline carbon, amorphous carbon, and / or any suitable combination thereof. Examples of crystalline carbon can include graphite, such as amorphous, plate-like, flaky, spherical, and / or fibrous natural graphite and / or artificial graphite, and examples of amorphous carbon can include soft carbon and / or hard carbon, mesophase pitch carbonization products, calcined coke, etc.

[0136] The lithium metal alloy can include an alloy containing lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0137] Si-based negative electrode active materials or Sn-based negative electrode active materials can be used as materials capable of doping and undoping lithium. Si-based negative electrode active materials can include silicon, silicon-carbon composites, SiO x (0 < x ≤ 2), Si-Q alloys (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 any suitable combination thereof, 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 any suitable combination thereof) and / or any suitable combination thereof. Sn-based negative electrode active materials can be Sn, SnO2, Sn alloys, and / or any suitable combination thereof.

[0138] The silicon-carbon composite can be a composite of silicon and amorphous carbon. The average particle size (D 50 ) can be, for example, about 0.5 μm to about 20 μm. According to some exemplary embodiments, the silicon-carbon composite can be in the form of 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 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 in the amorphous carbon matrix.

[0139] 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 an amorphous carbon coating on the surface of the core. The crystalline carbon can be artificial graphite, natural graphite, and / or any suitable combination thereof. The amorphous carbon can include soft carbon and / or hard carbon, mesophase pitch carbonization products, and / or calcined coke.

[0140] 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 may be about 10 wt% to about 50 wt%, and the content (e.g., amount) of amorphous carbon may be about 50 wt% to about 90 wt%. In one or more embodiments, if the silicon-carbon composite includes silicon, amorphous carbon, and crystalline carbon, based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of silicon may be about 10 wt% to about 50 wt%, and the content (e.g., amount) of crystalline carbon may be about 10 wt% to about 70 wt%, and the content (e.g., amount) of amorphous carbon may be about 20 wt% to about 40 wt%.

[0141] In some embodiments, the thickness of the amorphous carbon coating may be about 5 nm to about 100 nm. The average particle diameter (D 50 ) of the silicon particles (primary particles) may be about 10 nanometers (nm) to about 1 micrometer (μm) or about 10 nm to about 200 nm. The silicon particles may exist alone as silicon, in the form of a silicon alloy, and / or in an oxidized form of silicon. The oxidized form of silicon may be represented by SiO x (0 < x < 2). In this case, the atomic content (e.g., amount) ratio of Si:O indicating the degree of oxidation may be about 99:1 to about 33:67. In the present specification, as used herein, if (e.g., when) no other definition is provided, the average particle diameter (D 50 ) indicates the diameter of the particles with a cumulative volume of about 50 vol% in the particle size distribution. The average particle diameter (D 50 ) can be measured by appropriate techniques such as using a particle size analyzer, transmission electron microscopy, and / or scanning electron microscopy. Another method can be carried out by using a measuring device with dynamic light scattering, analyzing the data to calculate the number of particles relative to each particle size, and then calculating to obtain the average particle diameter (D 50 ). In the present specification, if the particles are spherical, "diameter" indicates the particle size, and if the particles are non-spherical, "diameter" indicates the major axis length.

[0142] Si-based negative electrode active materials and / or Sn-based negative electrode active materials can be used by mixing with carbon-based negative electrode active materials. If a mixture of Si-based negative electrode active materials and / or Sn-based negative electrode active materials and carbon-based negative electrode active materials is used, the mixing ratio by weight may be about 1:99 to about 90:10.

[0143] Negative electrode

[0144] 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.

[0145] Based on 100wt% of the negative electrode active material layer, the content (e.g., amount) of the negative electrode active material may be about 95wt% to about 99.5wt%. Based on 100wt% of the negative electrode active material layer, the content (e.g., amount) of the binder may be about 0.5wt% to about 5wt%. Based on 100wt% of the negative electrode active material layer, the content (e.g., amount) of the conductive material may be about 0.5wt% to about 5wt%. For example, the negative electrode active material layer may include about 90wt% to about 99wt% of the negative electrode active material, about 0.5wt% to about 5wt% of the binder, and about 0.5wt% to about 5wt% of the conductive material.

[0146] The binder is used to properly bind the negative electrode active material particles to each other and also helps to properly bind the negative electrode active material to the negative electrode current collector. The binder may be a non-aqueous binder, an aqueous binder, a dry binder and / or any appropriate combination thereof.

[0147] 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 any suitable combination thereof.

[0148] The aqueous binder can be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol and any appropriate combination thereof.

[0149] If the aqueous binder is used as the negative electrode binder, it may further include a cellulose compound capable of imparting appropriate viscosity. As such a cellulose compound, one or more selected from carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose and alkali metal salts thereof may be used. The alkali metal may be Na, K or Li.

[0150] The dry binder may be a suitable polymer material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and / or any suitable combination thereof.

[0151] Conductive materials are used to impart conductivity to the electrodes, and in the configured battery, any suitable conductive material may be used as long as it does not cause undesirable chemical changes in the battery. 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 / or carbon nanotube; metal-based materials including copper, nickel, aluminum, silver, etc. in the form of metal powder and / or metal fiber; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0152] The negative electrode current collector 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 any appropriate combination thereof.

[0153] Diaphragm

[0154] 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, may include) a polyethylene separator, a polypropylene separator, a polyvinylidene fluoride separator and / or a multilayer thereof (such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator and / or a polypropylene / polyethylene / polypropylene three-layer separator).

[0155] The separator may include a porous substrate and a coating on one or both surfaces (eg, opposite surfaces) of the porous substrate, the coating containing an organic material, an inorganic material, and / or any appropriate combination thereof.

[0156] The porous substrate may be a polymer film formed of any one (e.g., one) selected from polyolefins (e.g., polyethylene and / or polypropylene), polyesters (e.g., polyethylene terephthalate and / or polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyether ketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, and polytetrafluoroethylene (e.g., Teflon), or may be formed of copolymers of two or more thereof and / or mixtures of two or more thereof.

[0157] 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.

[0158] The organic material may include a (meth)acryl-based 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.

[0159] The inorganic material may include one or more inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and any appropriate combination thereof, but the present disclosure is not limited thereto. The average particle size (D 50 ) 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.

[0160] The organic material and the inorganic material may be mixed in one coating layer, or may exist in a stacked form of a coating layer including an organic material and a coating layer including an inorganic material.

[0161] The thickness of the coating layers may each be 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.

[0162] Rechargeable lithium battery

[0163] Rechargeable lithium batteries can be classified into cylindrical, prismatic, pouch, coin, etc., depending on their shapes. Figure 1 is a 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, the electrode assembly 40 includes a separator 30 inserted between a positive electrode 10 and a negative electrode 20, and the electrode assembly 40 is accommodated in the case 50. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte. The rechargeable lithium battery 100 may include a sealing member such as a sealing member for sealing the case 50. Figure 1 As shown in , and may further include an electrode tab 70 serving as an electrical path for guiding the current formed in the electrode assembly 40 to the outside, as shown in Figure 1 as shown in .

[0164] Hereinafter, examples and comparative examples of the present disclosure will be described. However, the following examples are merely embodiments of the present disclosure, and the present disclosure is not limited to the following examples.

[0165] Example 1

[0166] (1) Preparation of electrolyte

[0167] The nonaqueous organic solvent was prepared by mixing ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP), and propyl propionate (PP) in a volume ratio of 10:15:30:45.

[0168] 1.3 M of lithium salt (LiPF6) was added to the non-aqueous organic solvent, and then 10 wt % of the first additive represented by Chemical Formula 1-1-1 (CAS No. 2386-87-0) and 2 wt % of the second additive represented by Chemical Formula 2-1-1 (CAS No. 110-61-2) were added as additives to prepare the electrolyte of Example 1.

[0169] Chemical formula 1-1-1

[0170]

[0171] Chemical formula 2-1-1

[0172]

[0173] Herein, in the electrolyte composition, "wt %" is based on the total content (eg, amount) of the electrolyte (lithium salt+nonaqueous organic solvent+additives).

[0174] (2) Manufacturing of rechargeable lithium battery cells

[0175] LiCoO2 as a positive electrode active material, polyvinylidene fluoride as a binder, and Ketjen black as a conductive material were mixed at 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.

[0176] The positive electrode active material slurry was coated on a 14 μm thick Al foil, dried at 110° C., and pressed to produce a positive electrode.

[0177] 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 in a weight ratio of 97:1:2 were dispersed in distilled water to prepare a negative electrode active material slurry.

[0178] The negative electrode active material slurry was coated on a 10 μm-thick Cu foil, dried at 100° C., and pressed to manufacture a negative electrode.

[0179] An electrode assembly was manufactured by assembling the manufactured positive and negative electrodes and a 25 μm thick polyethylene separator, the electrode assembly was placed in a pouch, and a rechargeable lithium battery cell was manufactured by injecting the electrolyte of Example 1.

[0180] Example 2

[0181] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as Example 1, except that 10 wt % of the first additive represented by Chemical Formula 1-1-1 and 3 wt % of the second additive represented by Chemical Formula 2-2-1 (CAS No. 1772-25-4) were used.

[0182] Chemical formula 2-2-1

[0183]

[0184] Example 3

[0185] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that 10 wt % of the first additive represented by Chemical Formula 1-1-1 and 1 wt % of the second additive represented by Chemical Formula 2-1-1 were used.

[0186] Example 4

[0187] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that 10 wt % of the first additive represented by Chemical Formula 1-1-1 and 5 wt % of the second additive represented by Chemical Formula 2-1-1 were used.

[0188] Example 5

[0189] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that 5 wt % of the first additive represented by Chemical Formula 1-1-1 and 2 wt % of the second additive represented by Chemical Formula 2-1-1 were used.

[0190] Example 6

[0191] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that 7 wt % of the first additive represented by Chemical Formula 1-1-1 and 2 wt % of the second additive represented by Chemical Formula 2-1-1 were used.

[0192] Comparative Example 1

[0193] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that no additive was used at all.

[0194] Comparative Example 2

[0195] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that 2 wt % of the second additive represented by Chemical Formula 2-2-1 was used and the first additive was not used.

[0196] Comparative Example 3

[0197] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that 3 wt % of the second additive represented by Chemical Formula 2-2-1 was used and the first additive was not used.

[0198] Comparative Example 4

[0199] An electrolyte and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that 10 wt % of the first additive represented by Chemical Formula 1-1-1 was used and the second additive was not used.

[0200] Table 1

[0201] Unit: wt%

[0202]

[0203]

[0204] Evaluation Example: Thermal Exposure Evaluation

[0205] (1) Evaluation of thermal exposure at 138°C or 141°C

[0206] The heat exposure conditions of each of the rechargeable lithium battery cells of Comparative Examples 1, 2, and 4 and Examples 1 and 2 were evaluated.

[0207] Each of the rechargeable lithium battery cells was thermally exposed by increasing the temperature from room temperature to 138°C or 141°C at 5°C / min. and then maintaining at the achieved temperature for 1 hour. Subsequently, the change in voltage (V) over time (min.) was evaluated, and the results are shown in Figure 2 to Figure 11 middle.

[0208] See also Figure 2 to Figure 6 , if (for example, when) each of the rechargeable lithium battery cells is exposed to heat (elevated temperature) of 138° C., even if only one of the two types (kinds) of additives is used, the temperature rise in the corresponding battery cell can be prevented or reduced.

[0209] However, see Figure 7 to Figure 11 , if (e.g., when) each of the rechargeable lithium battery cells is exposed to an elevated temperature greater than 138°C (e.g., 141°C), the temperature rise in the corresponding battery cell can be prevented or reduced only when (e.g., when) two of the two types (kinds) of additives are combined.

[0210] (2) Thermal exposure test by temperature and initial resistance

[0211] The heat exposure test of each of the rechargeable lithium battery cells according to Examples 1 to 6 and Comparative Examples 1 to 4 was evaluated by temperature and initial resistance, and the results are shown in Table 2.

[0212] Heat exposure test passing temperature: After each of the rechargeable lithium battery cells is heated from room temperature to any temperature that the battery cell can withstand without overheating (e.g., 138°C or higher) at 5°C / min., it is allowed to stand at the reached temperature for 1 hour, and the reached temperature is evaluated as the "heat exposure test passing temperature".

[0213] Initial resistance: Each of the rechargeable lithium battery cells was evaluated by a DC resistance method under the conditions of 25° C. and SOC 100 (state of charge 100%).

[0214] Table 2

[0215]

[0216]

[0217] (3) Overview

[0218] Referring to Table 2, if (for example, when) only one type or kind of the two types (kinds) of additives of the present embodiment is used, the battery cell can withstand (only or at most) an elevated temperature of 138°C, but if (for example, when) two of the two types (kinds) of additives are combined, the battery cell can withstand an elevated temperature greater than 138°C (for example, 141°C).

[0219] Further, if (for example, when) 2 types (kinds) of additives are combined, taking the high temperature initial resistance into comprehensive consideration, the desired or appropriate content (for example, amount) of each of the additives and the desired or appropriate total content (for example, amount) of the additives are observed.

[0220] For example, the first additive may be used in an amount of 5 wt % to 10 wt %, and the second additive may be used in an amount of 1 wt % to 5 wt %, based on the total amount of the electrolyte.

[0221] Any suitable hardware, firmware (e.g., an application specific integrated circuit), software, or a combination of software, firmware, and hardware may be used to implement the vehicle, battery management system (BMS) device, and / or any other related device or component according to the embodiments of the present invention described herein. 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 that run on one or more processors in one or more computing devices, execute computer program instructions, and interact with other system components for performing the various functions described herein. The computer program instructions are stored in a memory that may be implemented in a computing device using a standard storage device, such as, for example, a random access memory (RAM). The computer program instructions may also be stored in other non-temporary computer-readable media, such as, for example, a CD-ROM or a flash drive, etc. Moreover, it should be recognized by those skilled in the art that 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 without departing from the scope of the present disclosure.

[0222] While the 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 on the contrary, the disclosure is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the claims and equivalents thereto.

Claims

1. An electrolyte comprising: Non-aqueous organic solvents; Lithium salts; A first additive represented by Chemical Formula 1; and As a second additive to nitrile additives: Chemical formula 1 In Chemical Formula 1, R 1 is C1-C10 alkyl, C3-C10 cycloalkyl, C2-C20 heterocycloalkyl including at least one heteroatom of N, O, S and P, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C2-C10 heteroaryl including at least one heteroatom of N, O, S and P, or *-(L 1 )-(L 2 )-R 2 ; L 1 is a single bond or *-(C=O)-O-*; L 2 is a single bond or a C1-C10 alkylene group; and R 2 is a hydrogen atom or a substituent represented by chemical formula A: Chemical formula A The electrolyte is used in a rechargeable lithium battery.

2. The electrolyte according to claim 1, wherein Chemical formula 1 is represented by Chemical formula 1-1 or Chemical formula 1-2: Chemical formula 1-1 Chemical formula 1-2 In Chemical Formula 1-1 and Chemical Formula 1-2, L 3 It is a C1-C10 alkylene group.

3. The electrolyte according to claim 1, wherein The first additive comprises at least one compound selected from the group consisting of: Chemical formula 1-1-1 Chemical formula 1-2-1 4. The electrolyte according to claim 1, wherein The second additive includes one or more polyfunctional nitrile compounds including two or more nitrile groups.

5. The electrolyte according to claim 4, wherein The second additive is represented by Chemical Formula 2: Chemical formula 2 NC-(L 3 ) a -(L 4 ) b -CN, In chemical formula 2, L 3 and L 4 Each independently represents an unsubstituted C1-C10 alkyleneoxy group, an unsubstituted C1-C10 alkylene group, or a C1-C10 alkylene group substituted with a cyano group; and a and b are each independently an integer of 0-3.

6. The electrolyte according to claim 5, wherein Chemical formula 2 is represented by Chemical formula 2-1 or Chemical formula 2-2: Chemical formula 2-1 NC-(L 5 ) c -(L 6 ) d -CN Chemical formula 2-2 In Chemical Formula 2-1 and Chemical Formula 2-2, L 5 ~L 8 Each is independently an unsubstituted C1-C10 alkyleneoxy group or an unsubstituted C1-C10 alkylene group; and c to f are each independently an integer of 0 to 3.

7. The electrolyte according to claim 6, wherein The second additive includes at least one compound selected from Chemical Formula 2-1-1, Chemical Formula 2-1-2 and Chemical Formula 2-2-1: Chemical formula 2-1-1 Chemical formula 2-1-2 Chemical formula 2-2-1 8. The electrolyte according to claim 1, wherein The weight ratio of the first additive to the second additive is 1:1 to 20:

1.

9. The electrolyte according to claim 1, wherein Based on the total amount of the electrolyte, the amount of the first additive is 1 wt % to 20 wt %.

10. The electrolyte according to claim 1, wherein Based on the total amount of the electrolyte, the amount of the second additive is 0.1 wt % to 10 wt %.

11. The electrolyte according to claim 1, wherein The non-aqueous organic solvent includes a carbonate solvent, an ester solvent or a combination thereof.

12. The electrolyte according to claim 11, wherein The non-aqueous organic solvent includes ethylene carbonate, propylene carbonate, ethyl propionate and / or propyl propionate.

13. A rechargeable lithium battery comprising: a positive electrode comprising a positive electrode active material; a negative electrode comprising a negative electrode active material; and The electrolyte according to any one of claims 1 to 12.

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