Electrolyte for rechargeable lithium battery and rechargeable lithium battery including same

Abstract

The invention relates to an electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the same. An electrolyte for a rechargeable lithium battery may include a lithium salt; a non-aqueous organic solvent; a first additive represented by Chemical Formula 1; and a second additive represented by Chemical Formula 2: Chemical Formula 1: R1-O-R2 Chemical Formula 2: R3-O-R4. The description of each chemical formula follows the specification.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0098400 filed in the Korean Intellectual Property Office on July 27, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of the present disclosure described herein relate to an electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the same. Background Art

[0004] Recently, with the rapid development of electronic devices using batteries, such as mobile phones, laptop computers and / or automobiles (e.g., electric vehicles), the demand for rechargeable batteries with relatively high energy density and relatively high capacity is increasing. Accordingly, research and development to improve the performance of rechargeable lithium batteries is expected.

[0005] A rechargeable lithium battery includes a positive electrode and a negative electrode each containing an active material capable of inserting and extracting lithium ions, and an electrolyte. If (for example, when) lithium ions are inserted into / extracted from the positive electrode and the negative electrode, electrical energy can be generated through oxidation and reduction reactions.

[0006] One interesting area of ​​research for rechargeable lithium batteries is to increase the density of the negative electrode. However, if (e.g., when) the density of the negative electrode is increased, the void volume may decrease, which may increase the amount of electrolyte impregnated into the negative electrode, resulting in an increase in battery thickness and a decrease in battery cycle life. Summary of the invention

[0007] Aspects according to one or more embodiments relate to an electrolyte for a rechargeable lithium battery that suppresses or reduces an increase in battery thickness and a decrease in cycle life even if (for example, when) the density of a negative electrode increases.

[0008] Aspects according to one or more embodiments relate to a rechargeable lithium battery including an electrolyte for a rechargeable lithium battery.

[0009] Aspects according to one or more embodiments relate to an electrolyte for a rechargeable lithium battery that can suppress or reduce an increase in battery thickness and a decrease in cycle life even if (for example, when) the density of a negative electrode increases.

[0010] 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.

[0011] According to one or more embodiments, an electrolyte for a rechargeable lithium battery may include a lithium salt; a non-aqueous organic solvent; a first additive represented by Chemical Formula 1; and a second additive represented by Chemical Formula 2:

[0012] Chemical formula 1

[0013] R 1 -OR 2

[0014] Chemical formula 2

[0015] R 3 -OR 4 .

[0016] According to one or more embodiments, a rechargeable lithium battery may include a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 to Figure 4 is a schematic diagram illustrating a rechargeable lithium battery according to one or more embodiments.

[0018] Reference numerals

[0019] 100: Rechargeable lithium battery 10: Positive electrode

[0020] 11: Positive electrode lead tab 12: Positive terminal

[0021] 20: Negative electrode 21: Negative electrode lead lug

[0022] 22: Negative terminal 30: Separator

[0023] 40: electrode assembly 50: shell

[0024] 60: Sealing member 70: Electrode terminal piece

[0025] 71: Positive electrode terminal tab 72: Negative electrode terminal tab DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present disclosure will be described in more detail. However, these embodiments are examples, the present disclosure is not limited thereto, and the present disclosure is defined by the scope of the claims.

[0027] As used herein, if (for example, when) no specific limitations are otherwise provided, 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 can be directly on the other element or intervening elements may also be present.

[0028] As used herein, if (for example, when) no specific limitation is provided in other ways, the singular may also include the plural. In one or more embodiments, unless otherwise indicated, "A or B" may mean "including A, including B, or including A and B".

[0029] As used herein, expressions such as “at least one of,” “one of,” and “(e.g., selected from) of,” when preceding / following a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, “at least one of a, b, and c,” “at least one selected from a, b, and c,” and the like 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.

[0030] The terms used in this article are intended to describe only specific embodiments, and are not intended to limit the present disclosure. As used in this article, the singular forms "a", "an" and "said" are intended to include plural forms, including "at least one", unless otherwise clearly indicated content (e.g., amount). "At least one" should not be interpreted as being limited to the singular. As used in this article, the term "and / or" includes any and all combinations of one or more related enumerated items. The terms "includes", "including", "comprises" and / or "comprising", when used in the detailed description, indicate that there are narrated features, regions, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components and / or groups thereof.

[0031] 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 the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation illustrated in the drawings. For example, when the device in the drawings is flipped, elements described as "below" or "below" other elements or features will be "above" or "on" other elements or features. In some embodiments, the example term "below" may (e.g., simultaneously) encompass both 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.

[0032] As used herein, the term "metal" includes all metals and metalloids, such as silicon and germanium, in either elemental or ionic form.

[0033] The term "alloy" as used herein refers to a mixture of two or more metals.

[0034] As used herein, the term "electrode active material" refers to an electrode material that can undergo lithiation and delithiation.

[0035] As used herein, the term "positive electrode active material" refers to a positive electrode material that can undergo lithiation and delithiation.

[0036] The term "negative electrode active material" as used herein refers to a negative electrode material that can undergo lithiation and delithiation.

[0037] As used herein, "lithiate" and "lithiating" refer to the process of adding lithium to an electrode active material.

[0038] As used herein, the terms "delithiate" and "delithiating" refer to the process of removing lithium from an electrode active material.

[0039] As used herein, the terms "charge" and "charging" refer to the process of providing electrochemical energy to a battery.

[0040] As used herein, the terms "discharge" and "discharging" refer to the process of removing electrochemical energy from a battery.

[0041] The terms "positive electrode" and "cathode" as used herein refer to the electrode that undergoes electrochemical reduction and lithiation during the discharge process.

[0042] The terms "negative electrode" and "anode" as used herein refer to the electrode at which electrochemical oxidation and delithiation occur during the discharge process.

[0043] As used herein, the term "substantially" and similar terms are used as terms of approximation rather than as terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that one of ordinary skill in the art would recognize. Also, "about" and similar terms, when used herein in conjunction with a value or range of values, include both the stated value and values ​​within an acceptable range of deviation for the particular value determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (e.g., limitations of the measurement system). For example, "about" may mean within one or more standard deviations of the stated value, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0044] Furthermore, any numerical range set forth in this article is intended to include all sub-ranges of the same numerical precision falling within the set forth range. For example, the range of "1.0-10.0" is intended to be included between the set forth minimum value 1.0 and the set forth maximum value 10.0 (and including the end value), that is, all sub-ranges (such as, for example, 2.4-7.6) having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0. Any maximum numerical limit set forth in this article is intended to include all lower numerical limits falling therein, and any minimum numerical limit set forth in this specification is intended to include all higher numerical limits falling therein. Accordingly, the applicant reserves the right to modify this specification (including claims) to explicitly set forth any sub-range falling within the range explicitly set forth in this article.

[0045] As used herein, "combinations thereof" may refer to mixtures, stacks, composites, copolymers, alloys, blends, and reaction products of the components.

[0046] As used herein, “active mass density of the negative electrode (referred to simply as density of the negative electrode)” is a value calculated by dividing the weight of components (active material, conductive material, binder, etc.) in the negative electrode other than the negative electrode current collector by its volume.

[0047] As used herein, if (e.g., when) no definition is otherwise provided, in a chemical formula, if (e.g., when) a chemical bond is not drawn at a position where a chemical bond should be drawn, a hydrogen atom is bonded to that position.

[0048] As used herein, "fluoroalkyl" refers to an alkyl group in which some or all of the hydrogen atoms are replaced by fluorine atoms.

[0049] As used herein, "perfluoroalkyl" refers to an alkyl group in which all hydrogen atoms are replaced by fluorine atoms.

[0050] Electrolyte

[0051] One or more embodiments provide an electrolyte for a rechargeable lithium battery, which includes a lithium salt; a non-aqueous organic solvent; a first additive represented by Chemical Formula 1; and a second additive represented by Chemical Formula 2:

[0052] Chemical formula 1

[0053] R 1 -OR 2

[0054] Chemical formula 2

[0055] R 3 -OR 4 .

[0056] The first additive and the second additive each function as a surfactant having both a hydrophilic group and a hydrophobic group in one molecule (eg, simultaneously).

[0057] The first additive includes an ether group at the center and fluorine atoms or fluoroalkyl groups having 1 to 10 carbon atoms at both sides (eg, opposite sides). Herein, the ether group is a hydrophilic group, and the fluorine atom and the fluoroalkyl group having 1 to 10 carbon atoms are hydrophobic groups.

[0058] In one or more embodiments, the second additive includes an ether group at the center and includes a fluorine atom, an alkyl group having 1 to 10 carbon atoms, or a fluoroalkyl group having 1 to 10 carbon atoms on both sides (e.g., opposite sides). Herein, the ether group is a hydrophilic group, and the fluorine atom, the C1 to C10 alkyl group, and the C1 to C10 fluoroalkyl group are hydrophobic groups.

[0059] In one or more embodiments, Chemical Formula 1 and Chemical Formula 2 may be different from each other.

[0060] Accordingly, if (for example, when) an electrolyte that simultaneously (for example, simultaneously) includes the first additive and the second additive is used, the wettability of the positive electrode and the negative electrode is improved, lithium cations (Li+) are uniformly formed (for example, substantially uniformly formed) at the interface between the positive electrode and the electrolyte, and a stable SEI film is formed at the interface between the negative electrode and the electrolyte, inhibiting or reducing the precipitation of lithium dendrites.

[0061] Therefore, if an electrolyte including both the first additive and the second additive (eg, including both the first additive and the second additive at the same time) is used, an increase in the thickness of the battery and a decrease in the cycle life can be suppressed or reduced even if the density of the negative electrode is increased.

[0062] Hereinafter, an electrolyte according to one or more embodiments will be described in more detail.

[0063] First Additive

[0064] In Chemical Formula 1, R 1 and R 2 Each independently may be a fluorine atom or a C1-C10 fluoroalkyl group.

[0065] For example, R 1 It may be a fluoroalkyl group having 2 carbon atoms.

[0066] In addition, R 2 It may be a fluoroalkyl group having 3 carbon atoms.

[0067] The first additive can be represented by Chemical Formula 1-1:

[0068] Chemical formula 1-1

[0069]

[0070] In Chemical Formula 1-1, R 11 ~R 15 are each a hydrogen atom or a fluorine atom, provided that R 11 ~R 15 At least one of is a fluorine atom; and R 21 ~R 27 are each a hydrogen atom or a fluorine atom, provided that R 21 ~R 27 At least one of them is a fluorine atom.

[0071] An example of the first additive may be represented by Chemical Formula 1-1-1:

[0072] Chemical formula 1-1-1

[0073]

[0074] Second additive

[0075] In chemical formula 2, R 3 and R 4 Each independently may be a fluorine atom, a C1-C10 alkyl group or a C1-C10 fluoroalkyl group.

[0076] For example, R 3 It may be a fluoroalkyl group having 3 carbon atoms, for example, a perfluoroalkyl group having 3 carbon atoms.

[0077] In addition, R 4 It may be an alkyl group or a fluoroalkyl group having 1 carbon atom.

[0078] The second additive can be represented by Chemical Formula 2-1:

[0079] Chemical formula 2-1

[0080]

[0081] In Chemical Formula 2-1, R 31 ~R 37 are each a hydrogen atom or a fluorine atom, provided that R 31 ~R 37 At least one of is a fluorine atom; and R 41 ~R 43 Each is a hydrogen atom or a fluorine atom.

[0082] An example of the second additive may be represented by Chemical Formula 2-1-1:

[0083] Chemical formula 2-1-1

[0084]

[0085] Content of the first additive and the second additive

[0086] The first additive may be included in an amount of about 1 wt % to about 10 wt %, about 1 wt % to about 5 wt %, or about 1 wt % to about 3 wt % based on the total amount of the electrolyte.

[0087] If the first additive is included in an amount exceeding the above range, the viscosity of the electrolyte including the first additive may be excessively (or significantly) increased, and the wettability of the positive electrode and the negative electrode may actually decrease. In contrast, if the first additive is included in an amount less than the above range, the effect of the first additive as a surfactant may be minimal.

[0088] The second additive may be included in an amount of about 1 wt % to about 10 wt %, about 1 wt % to about 5 wt %, or about 1 wt % to about 3 wt %, based on the total amount of the electrolyte.

[0089] If the second additive is included in excess of the above range, the viscosity of the electrolyte including the second additive may be excessively (or significantly) increased, and the wettability of the positive electrode and the negative electrode may actually decrease. In contrast, if the second additive is included in a small amount below the above range, the effect of the second additive as a surfactant may be minimal.

[0090] The weight ratio of the first additive to the second additive in the electrolyte may be about 10:1 to about 1:10, about 5:1 to about 1:5, or about 3:1 to about 1:3.

[0091] When the weight ratio of the first additive to the second additive is within these ranges, the effects of the first additive and the second additive can be coordinated.

[0092] Non-aqueous organic solvent

[0093] The non-aqueous organic solvent is used as a medium for transmitting ions participating in the electrochemical reaction of the battery. The non-aqueous organic solvent may include a carbonate solvent, an ester solvent (e.g., a propionate solvent), an ether solvent, a ketone solvent, an alcohol solvent, an aprotic solvent and / or a combination thereof (e.g., a suitable combination thereof).

[0094] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (MEC), 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, propyl propionate, decanoic acid lactone, mevalonolactone, valerolactone, caprolactone, etc.

[0095] Ether solvents may include dibutyl ether, tetraglyme, diglyme, 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 nitrile (such as R-CN, wherein R is a C2-C20 straight chain, branched chain or cyclic hydrocarbon group, and includes a double bond, an aromatic ring or an ether group), amide (such as dimethylformamide), dioxolane (such as 1,3-dioxolane or 1,4-dioxolane), sulfolane, etc.

[0096] A single nonaqueous organic solvent may be used or a combination of two or more of them may be used.

[0097] In one or more embodiments, the non-aqueous organic solvent may include a carbonate-based solvent and a propionate-based solvent.

[0098] The propionate-based solvent may be included in an amount greater than or equal to about 70% by volume based on the total amount of the non-aqueous organic solvent. In this case, relatively high voltage and / or relatively high temperature characteristics of a rechargeable lithium battery may be improved.

[0099] For example, the nonaqueous organic solvent may be a mixed solvent of ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP), and propyl propionate (PP).

[0100] Lithium salts

[0101] The lithium salt dissolved in the nonaqueous organic solvent supplies lithium ions in 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.

[0102] For example, LiPF6 may be used as the lithium salt.

[0103] The concentration of the lithium salt may be about 0.1M to about 2.0M.

[0104] Rechargeable lithium battery

[0105] One or more 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.

[0106] Active mass density of negative electrode

[0107] Generally, rechargeable lithium batteries utilize negative electrodes having an active mass density of less than about 1.68 g / cc, but rechargeable lithium batteries according to one or more embodiments use negative electrodes having an active mass density (e.g., mixed density) greater than or equal to about 1.68 g / cc.

[0108] The upper limit of the active mass density of the negative electrode is not particularly limited, but may be less than or equal to about 2.0 g / cc, less than or equal to about 1.9 g / cc, or less than or equal to about 1.8 g / cc.

[0109] Charging upper limit voltage

[0110] Since the rechargeable lithium battery according to one or more embodiments includes the electrolyte of the aforementioned embodiments, even if the density of the negative electrode is increased, an increase in thickness and a decrease in cycle life may be suppressed or reduced.

[0111] For example, a rechargeable lithium battery may have a charge upper limit voltage greater than or equal to about 4.4V.

[0112] Hereinafter, a description repeated above will not be provided, and a rechargeable lithium battery according to one or more embodiments will be described in more detail.

[0113] Positive electrode active material

[0114] The positive electrode active material may be a compound capable of intercalating and deintercalating lithium (lithiated intercalation compound). For example, a composite oxide of lithium and one or more types (kinds) of metals selected from cobalt, manganese, nickel, and combinations thereof (eg, appropriate combinations thereof) may be used.

[0115] 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 (eg, appropriate combinations thereof).

[0116] As an example, a compound represented by (eg, selected from) any one of the following chemical formulas may 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 Mn 1-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); and / or Li a FePO4(0.90≤a≤1.8).

[0117] In the above chemical formula, A is Ni, Co, Mn and / or a combination thereof (e.g., a suitable combination thereof); X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element and / or a combination thereof (e.g., a suitable combination thereof); D is O, F, S, P and / or a combination thereof (e.g., a suitable combination thereof); G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V and / or a combination thereof (e.g., a suitable combination thereof); and L 1is Mn, Al and / or a combination thereof (eg, a suitable combination thereof).

[0118] As an example, based on about 100 mol% of the metal other than lithium in the lithium transition metal composite oxide, the positive electrode active material may have a nickel content (e.g., amount) greater than or equal to about 80 mol%, greater than or equal to about 85 mol%, greater than or equal to about 90 mol%, greater than or equal to about 91 mol%, or greater than or equal to about 94 mol%. In one or more embodiments, based on about 100 mol% of the metal other than lithium in the lithium transition metal composite oxide, the positive electrode active material may be a relatively high nickel-based positive electrode active material having a nickel content (e.g., amount) less than or equal to about 99 mol%. Relatively 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.

[0119] The positive electrode active material may be or include, for example, a lithium nickel-based oxide represented by Chemical Formula 11, a lithium cobalt-based oxide represented by Chemical Formula 12, a lithium iron phosphate-based compound represented by Chemical Formula 13, a cobalt-free lithium nickel manganese-based oxide represented by Chemical Formula 14, and / or combinations thereof (e.g., appropriate combinations thereof).

[0120] Chemical formula 11

[0121] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0122] In Chemical Formula 11, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, M 1 and M 2 Each of them may independently be one or more elements selected from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W and Zr, and X may be one or more elements selected from F, P and S.

[0123] In Chemical Formula 1, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0124] Chemical formula 12

[0125] Li a2 Cox2 M 3 y2 O 2-b2 X b2

[0126] In Chemical Formula 12, 0.9 ≤ a2 ≤ 1.8, 0.7 ≤ x2 ≤ 1, 0 ≤ y2 ≤ 0.3, 0.9 ≤ x2 + y2 ≤ 1.1, and 0 ≤ b2 ≤ 0.1, M 3 is one or more elements selected from Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and X is one or more elements selected from F, P, and S.

[0127] Chemical Formula 13

[0128] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0129] In Chemical Formula 13, 0.9 ≤ a3 ≤ 1.8, 0.6 ≤ x3 ≤ 1, 0 ≤ y3 ≤ 0.4, 0.9 ≤ x3 + y3 ≤ 1.1 and 0 ≤ b3 ≤ 0.1, M 4 is one or more elements selected from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and X is one or more elements selected from F, P, and S.

[0130] Chemical Formula 14

[0131] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0132] In Chemical Formula 14, 0.9 ≤ a2 ≤ 1.8, 0.8 ≤ x4 < 1, 0 < y4 ≤ 0.2, 0 ≤ z4 ≤ 0.2, 0.9 ≤ x4 + y4 + z4 ≤ 1.1, and 0 ≤ b4 ≤ 0.1M 5 is one or more elements selected from Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from F, P, and S.

[0133] For example, the electrolyte of the above-described embodiment may utilize the lithium cobalt-based oxide represented by Chemical Formula 12 to significantly improve the relatively high voltage and / or relatively high temperature characteristics of the battery.

[0134] Positive electrode

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

[0136] For example, the positive electrode may further include an additive that may function as a sacrificial positive electrode.

[0137] The content (eg, amount) of the positive electrode active material may be about 90 wt % to about 99 wt % based on about 100 wt % of the positive electrode active material layer, and the content (eg, amount) of the binder and the conductive material may be about 0.5 wt % to about 5 wt %, respectively.

[0138] The binder is used to attach the positive electrode active material particles to each other well, and also to attach the positive electrode active material to the positive electrode current collector well. Examples of binders 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, nylon, etc. as non-limiting examples.

[0139] Conductive materials can be used to impart conductivity (e.g., electrical conductivity) to the electrodes. Any material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in a rechargeable lithium battery) and conducts electrons can be used 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 fibers, carbon nanofibers, and carbon nanotubes); metal-based materials in the form of metal powders or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers (such as polyphenylene derivatives); and / or mixtures thereof (e.g., appropriate mixtures thereof).

[0140] Al foil may be used as a positive electrode current collector, 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 / dedoping lithium, or a transition metal oxide.

[0143] Materials capable of reversibly embedding / desorbing lithium ions may include carbonaceous negative electrode active materials, such as crystalline carbon, amorphous carbon, and / or combinations thereof (e.g., suitable combinations thereof). The crystalline carbon may be graphite, such as amorphous, flaky, lamellar, spherical, or fibrous natural graphite or artificial graphite. The amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbonization products, calcined coke, etc.

[0144] The lithium metal alloy may include lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0145] Materials capable of doping / dedoping lithium may be Si-based negative electrode active materials or Sn-based negative electrode active materials. The Si-based negative electrode active materials may include silicon, silicon-carbon composites, SiO x (0 < x ≤ 2), Si-Q alloys (where Q is 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., suitable combinations thereof)). The Sn-based negative electrode active materials may include Sn, SnO x (0 < x ≤ 2) (e.g., SnO2), Sn-based alloys, and / or combinations thereof (e.g., suitable combinations thereof).

[0146] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one or more embodiments, the silicon-carbon composite may be or include silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite may include secondary particles (cores) in which primary silicon particles are aggregated and an amorphous carbon coating (shell) on the surface of the secondary particles. The amorphous carbon may also be between the primary silicon particles, and, for example, the primary silicon particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0147] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles and an amorphous carbon coating on the surface of the core.

[0148] The Si-based negative electrode active materials or the Sn-based negative electrode active materials may be used in combination with the carbonaceous negative electrode active materials.

[0149] Negative electrode

[0150] 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 negative electrode active materials and may further include a binder and / or a conductive material.

[0151] For example, the negative electrode active material layer may 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 wt % to about 5 wt % of the conductive material based on about 100 wt % of the negative electrode active material layer.

[0152] The binder can be used to attach the negative electrode active material particles to each other well, and also to attach the negative electrode active material to the negative electrode current collector well. The binder may include a non-aqueous binder, an aqueous binder, a dry binder, and / or a combination thereof (eg, a suitable combination thereof).

[0153] 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, appropriate combinations thereof).

[0154] 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 / or combinations thereof (e.g., appropriate combinations thereof).

[0155] When the aqueous binder is used as a binder in the negative electrode active material layer, it may further include a cellulose compound capable of imparting viscosity. The cellulose compound includes one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose and alkali metal salts thereof. The alkali metal may be Na, K or Li.

[0156] The dry binder may be a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, a polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and / or a combination thereof (eg, a suitable combination thereof).

[0157] A conductive material is included to provide electrode conductivity, and any conductive material can be used as the conductive material unless it causes chemical changes (e.g., causes undesirable chemical changes in a rechargeable lithium battery). Examples of the conductive material may be 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; conductive polymers (such as polyphenylene derivatives); and / or mixtures thereof (e.g., appropriate mixtures thereof).

[0158] The negative electrode current collector may include one 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, appropriate combinations thereof), but the present disclosure is not limited thereto.

[0159] Diaphragm

[0160] Depending on the type or kind of the rechargeable lithium battery, the separator may be present between the positive electrode and the negative electrode. The separator may include a polyethylene separator, a polypropylene separator, a polyvinylidene fluoride separator, or a multilayer film of two or more layers thereof (such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, a polypropylene / polyethylene / polypropylene three-layer separator, etc.).

[0161] The separator may include a porous substrate and a coating on a surface (e.g., one or both surfaces (e.g., opposite surfaces or opposite sides)) of the porous substrate, the coating including an organic material, an inorganic material and / or a combination thereof (e.g., a suitable combination thereof).

[0162] The porous substrate may be a polymer film formed by: any one of a polymer selected from polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyether ketones, polyarylether ketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, and polytetrafluoroethylene (e.g., TEFLON), or a copolymer of two or more thereof or a mixture of two or more thereof.

[0163] The organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0164] The inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite and / or combinations thereof (e.g., appropriate combinations thereof), but the present disclosure is not limited thereto.

[0165] An organic material and an inorganic material may be mixed in one coating layer, or a coating layer including an organic material and a coating layer including an inorganic material may be stacked.

[0166] Rechargeable lithium battery

[0167] The rechargeable lithium batteries may be classified into a cylindrical, a prismatic, a pouch type or battery-like, a coin type or battery-like, etc., depending on their shape. Figure 1 to Figure 4A schematic diagram illustrating a rechargeable lithium battery according to one or more embodiments. Figure 1 A cylindrical battery is shown, Figure 2 A prismatic cell is shown, and Figure 3 and Figure 4 Pouch type or similar battery is shown. Figure 1 to Figure 4 , the rechargeable lithium battery 100 may include an electrode assembly 40 including a separator 30 between a positive electrode 10 and a negative electrode 20, and a case 50 in which the electrode assembly 40 is accommodated. 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 60 that seals the case 50, such as Figure 1 As shown. Figure 2 In the embodiment, the rechargeable lithium battery 100 may include a positive electrode lead tab 11, a positive terminal 12, a negative electrode lead tab 21, and a negative terminal 22. Figure 3 and Figure 4 As shown, the rechargeable lithium battery 100 may include electrode tabs 70 , which may be, for example, a positive electrode tab 71 and a negative electrode tab 72 serving as an electrical path for guiding current formed in the electrode assembly 40 to the outside.

[0168] The rechargeable lithium battery according to one or more embodiments may be applied to automobiles, mobile phones, and / or one or more appropriate types (kinds) of electronic devices, but the present disclosure is not limited thereto.

[0169] Hereinafter, examples and comparative examples of the present disclosure are described. However, these examples are not to be construed as limiting the scope of the present disclosure in any sense.

[0170] Examples and Comparative Examples

[0171] The electrolyte and rechargeable lithium battery cells were prepared as follows.

[0172] Example 1

[0173] (1) Preparation of electrolyte

[0174] 1.3 M LiPF6 is dissolved in a non-aqueous organic solvent in which ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP) and propyl propionate (PP) are mixed in a volume ratio of about 10:15:30:45, and about 1 wt % of a first additive and about 1 wt % of a second additive are added thereto based on the total amount of the electrolyte to prepare an electrolyte.

[0175] A first additive represented by Chemical Formula 1-1-1 is used, and a second additive represented by Chemical Formula 2-1 is used:

[0176] Chemical formula 1-1-1

[0177]

[0178] 1,1,2,2-Tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (CAS No.: 16627-68-2)

[0179] Chemical formula 2-1-1

[0180]

[0181] 1,1,1,2,2,3,3-Heptafluoro-3-methoxypropane (CAS No.: 375-03-1)

[0182] (2) Preparation of rechargeable lithium battery cells

[0183] LiCoO 2 as a positive electrode active material, polyvinylidene fluoride as a binder, and acetylene black as a conductive material were mixed at a weight ratio of about 96:3:1, respectively, and then dispersed in N-methylpyrrolidone to prepare a positive electrode active material slurry.

[0184] The positive electrode active material slurry was coated on a 15 μm thick Al foil, dried at about 100° C., and pressed to prepare a positive electrode.

[0185] Artificial graphite as a negative electrode active material, a styrene-butadiene rubber binder, and carboxymethyl cellulose were dispersed in distilled water at a weight ratio of about 98:1:1 to prepare a negative electrode active material slurry.

[0186] The negative electrode active material slurry was coated on a Cu foil having a thickness of about 10 μm, dried at about 100° C., and pressed to prepare a negative electrode. At this time, the active mass density of the negative electrode was set to about 1.68 g / cc.

[0187] An electrode assembly was prepared by assembling a positive electrode, a negative electrode, and a separator made of polyethylene having a thickness of about 10 μm, and an electrolyte was injected to prepare a rechargeable lithium battery cell.

[0188] Example 2

[0189] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when preparing the electrolyte, about 1 wt % of the first additive and about 3 wt % of the second additive were added.

[0190] Example 3

[0191] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when preparing the electrolyte, about 1 wt % of the first additive and about 5 wt % of the second additive were added.

[0192] Example 4

[0193] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when preparing the electrolyte, about 3 wt % of the first additive and about 3 wt % of the second additive were added.

[0194] Example 5

[0195] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when preparing the electrolyte, about 5 wt % of the first additive and about 5 wt % of the second additive were added.

[0196] Example 6

[0197] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when the negative electrode was prepared, the active mass density of the negative electrode was set to about 1.75 g / cc.

[0198] Example 7

[0199] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when the negative electrode was prepared, the active mass density of the negative electrode was set to about 1.8 g / cc.

[0200] Comparative Example 1 (reference)

[0201] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that no additive was added when preparing the electrolyte.

[0202] Comparative Example 2

[0203] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when preparing the electrolyte, the second additive was not added and about 1 wt % of the first additive was added.

[0204] Comparative Example 3

[0205] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when preparing the electrolyte, the second additive was not added and about 3 wt % of the first additive was added.

[0206] Comparative Example 4

[0207] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that when preparing the electrolyte, the first additive was not added and about 1 wt % of the second additive was added.

[0208] Comparative Example 5

[0209] An electrolyte and a rechargeable lithium battery cell were prepared in substantially the same manner as in Example 1, except that if (eg, when) the electrolyte was prepared, the first additive was not added and about 3 wt % of the second additive was added.

[0210] Evaluation Example

[0211] The negative electrodes and rechargeable lithium battery cells were evaluated in the following manner.

[0212] Evaluation 1: Impregnation characteristics of the negative electrode with the electrolyte

[0213] The negative electrode according to Example 1 was prepared as a sample of width × (e.g., *) length = about 3 cm × about 5 cm. About 0.01 g of the electrolyte according to Example 1 was dropped on the sample and left for about 20 minutes. Thereafter, the amount of the electrolyte immersed in the sample in about 100 wt % of the electrolyte dropped on the sample was evaluated as a value of 0 to 5 according to the following standard, and the evaluation results are shown in Table 1:

[0214] 0: When the amount of the electrolyte immersed in the sample is 0 wt% or more and less than about 10 wt%

[0215] 1: When the amount of the electrolyte immersed in the sample is about 10 wt % or more and less than about 20 wt %

[0216] 2: When the amount of the electrolyte immersed in the sample is about 20 wt % or more and less than about 40 wt %

[0217] 3: When the amount of the electrolyte immersed in the sample is about 40 wt % or more and less than about 60 wt %

[0218] 4: When the amount of the electrolyte immersed in the sample is about 60 wt % or more and less than about 80 wt %

[0219] 5: When the amount of electrolyte immersed in the sample is 80wt% or more and less than about 100wt%

[0220] Each of the negative electrodes according to Example 2 to Example 7 and Comparative Example 1 to Comparative Example 5 was evaluated in substantially the same manner as in Evaluation Example 1, and the evaluation results are shown in Table 1.

[0221] Table 1

[0222]

[0223] Evaluation 2: Evaluation of room temperature charge and discharge cycle characteristics

[0224] Each of the rechargeable lithium battery cells prepared in Examples 1 to 7 and Comparative Examples 1 to 5 was charged and discharged about 200 times under the conditions of about 25° C., about 2.0C charge (CC / CV, 4.47V, 0.025C cutoff) / about 1.0C discharge (CC, 3V cutoff).

[0225] The fully charged thickness after the 1st cycle and the fully charged thickness after the 200th cycle of each of the rechargeable lithium battery cells prepared in Examples 1 to 7 and Comparative Examples 1 to 5 were measured, and the discharge capacity after the 1st cycle, after the 50th cycle, after the 100th cycle, and after the 200th cycle of each of the rechargeable lithium battery cells prepared in Examples 1 to 7 and Comparative Examples 1 to 5 was measured. The thickness increase rate was calculated according to Equation 1, the capacity retention rate was calculated according to Equation 2, and the results are shown in Table 2.

[0226] Equation 1

[0227] Thickness increase rate = {(fully charged thickness after 200th cycle) - fully charged thickness after 1st cycle)} / (fully charged thickness after 1st cycle) × 100

[0228] In Equation 1, "fully charged thickness" refers to the thickness of a rechargeable lithium battery cell measured after charging at about SOC 100% (charged to about 100% charge capacity if (e.g., when) the total charge capacity of the battery is set to about 100%) after each cycle.

[0229] Equation 2

[0230] Capacity retention rate = (discharge capacity after the nth cycle / discharge capacity after the first cycle) × 100

[0231] Table 2

[0232]

[0233] summary

[0234] Referring to Table 1 and Table 2, when the electrolyte does not include the additive at all (Comparative Example 1), the thickness of the battery cell including the negative electrode having a relatively high density increases and the cycle life is drastically reduced.

[0235] However, when the active mass density of the negative electrode is also set to about 1.68 g / cc, the electrolyte that synchronously (e.g., simultaneously) includes the first additive and the second additive (Examples 1 to 5) exhibits increased impregnation properties of the electrolyte to the negative electrode, reduced thickness of the battery cell and increased cycle life at relatively high temperatures and relatively high voltages, compared to the electrolyte that does not include any additives at all (Comparative Example 1).

[0236] In contrast, in the case where the electrolyte includes only one additive selected from the first additive and the second additive (Comparative Examples 2 and 3), the electrolyte has poor impregnation characteristics for the negative electrode, and the amount of free liquid increases, and the cycle life of the battery cell of Comparative Example 2 is sharply reduced, which is comparable to (for example, when) using an electrolyte (Comparative Example 1) that does not contain any additive. Accordingly, it is desirable to use an electrolyte that simultaneously (for example, simultaneously) includes the first additive and the second additive.

[0237] In addition, the electrolyte that synchronously (e.g., simultaneously) includes the first additive and the second additive suppresses or reduces the increase in battery thickness and the decrease in cycle life even if the active mass density of the negative electrode is increased from about 1.68 g / cc to about 1.8 g / cc (Examples 6 and 7).

[0238] In the present disclosure, "does not include one or any 'component'", "excludes one or any 'component'", "no 'component'" and the like mean that the "component" is not added, selected or used as a component in the composition or compound, but due to other impurities and / or external factors, the "component" may still be included in an amount less than the appropriate amount.

[0239] The battery management system (BMS) device and / or any other related device or component according to the embodiments of the present invention described herein may be implemented using any appropriate hardware, firmware (e.g., a dedicated integrated circuit), software, or a combination of software, firmware, and hardware. For example, one or more appropriate components of the device may be formed on an integrated circuit (IC) chip or on a separate IC chip. Further, one or more appropriate 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, one or more appropriate components of the device may be a process or thread running on one or more processors in one or more computing devices, executing computer program instructions and interacting with other system components to perform one or more appropriate 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-temporary computer-readable media (such as, for example, a CD-ROM, a flash drive, etc.). Moreover, those skilled in the art should recognize that without departing from the scope of the present disclosure, the functions of one or more appropriate 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.

[0240] In the present disclosure, "does not include one or any 'component'", "excludes one or any 'component'", "no 'component'" and the like mean that the "component" is not added, selected or used as a component in the composition or compound, but due to other impurities and / or external factors, the "component" may still be included in an appropriate amount.

[0241] While the invention has been described in connection with what are presently considered to be practical example embodiments, it should be understood that the disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the claims and their equivalents.

Claims

1. An electrolyte comprising: Lithium salts; Non-aqueous organic solvents; A first additive represented by Chemical Formula 1; as well as The second additive represented by Chemical Formula 2: Chemical formula 1 R 1 -O-R 2 Wherein in Chemical Formula 1, R 1 and R 2 Each is independently a fluorine atom or a C1-C10 fluoroalkyl group; Chemical formula 2 R 3 -O-R 4 Wherein in Chemical Formula 2, R 3 and R 4 are each independently a fluorine atom, a C1-C10 alkyl group or a C1-C10 fluoroalkyl group, wherein Chemical Formula 1 and Chemical Formula 2 are different from each other, and The electrolyte is used in a rechargeable lithium battery.

2. 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, R 11 ~R 15 are each a hydrogen atom or a fluorine atom, provided that they are selected from R 11 ~R 15 At least one of is a fluorine atom; and R 21 ~R 27 are each a hydrogen atom or a fluorine atom, provided that they are selected from R 21 ~R 27 At least one of them is a fluorine atom.

3. The electrolyte according to claim 1, wherein The first additive is represented by chemical formula 1-1-1: Chemical formula 1-1-1 4. The electrolyte according to claim 1, wherein The second additive is represented by chemical formula 2-1: Chemical formula 2-1 In chemical formula 2-1, R 31 ~R 37 are each a hydrogen atom or a fluorine atom, provided that they are selected from R 31 ~R 37 At least one of is a fluorine atom; and R 41 ~R 43 Each is a hydrogen atom or a fluorine atom.

5. The electrolyte according to claim 1, wherein The second additive is represented by chemical formula 2-1-1: Chemical formula 2-1-1 6. 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 10 wt %.

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

8. The electrolyte according to claim 1, wherein The weight ratio of the first additive to the second additive is 10:1 to 1:

10.

9. The electrolyte according to claim 1, wherein The non-aqueous organic solvent includes carbonate solvents and propionate solvents.

10. The electrolyte according to claim 9, wherein Based on the total amount of the non-aqueous organic solvent, the amount of the propionate solvent is greater than or equal to 70 volume %.

11. The electrolyte according to claim 1, wherein The lithium salt is LiPF6.

12. The electrolyte according to claim 1, wherein The concentration of the lithium salt is 0.1M to 2.0M.

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

14. The rechargeable lithium battery according to claim 13, wherein The negative electrode has an active mass density greater than or equal to 1.68 g / cc.

15. The rechargeable lithium battery according to claim 13, wherein The positive electrode active material includes lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate compound, cobalt-free lithium nickel manganese oxide or a combination thereof.

16. The rechargeable lithium battery according to claim 13, wherein The negative electrode active material includes a carbon-based negative electrode active material, a Si-based negative electrode active material or a combination thereof.

17. The rechargeable lithium battery according to claim 13, wherein The rechargeable lithium battery has a charge upper limit voltage greater than or equal to 4.4V.

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