Rechargeable lithium battery

Abstract

The invention relates to a rechargeable lithium battery. The rechargeable lithium battery includes: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte, in which the composite density of the negative electrode is at least 1.7 g / cc, and the electrolyte includes: a lithium salt; a non-aqueous organic solvent; a first additive represented by Formula 1; a second additive represented by Formula 2; and a third additive represented by Formula 3: Formula 1 R1-O-R2, Formula 2 # imgabs 0 #, Formula 3 # imgabs 1 #

Description

Technical Field

[0001] One or more embodiments of the present disclosure relate to a rechargeable lithium battery. Background Art

[0002] In recent years, with the rapid spread and popularization of electronic devices using batteries (such as mobile phones, laptop computers and / or electric vehicles), the demand for secondary batteries with relatively high energy density and relatively high capacity has increased rapidly. Therefore, research and development to improve the performance of rechargeable lithium batteries is being actively carried out or is being promoted.

[0003] A rechargeable lithium battery is a battery including positive and negative electrodes (each including an active material capable of inserting and deinserting lithium ions) and an electrolyte, and generates electric energy through oxidation and reduction reactions when lithium ions are inserted or deinserted at the positive and negative electrodes.

[0004] One of the latest developments in rechargeable lithium batteries is to densify the negative electrode. However, densifying the negative electrode reduces the void volume of the negative electrode, which increases the amount of electrolyte that impregnates the negative electrode (e.g., rather than being contained in the void volume); therefore, the thickness of the battery (e.g., battery cell) increases, and the life of the battery decreases. Summary of the invention

[0005] One or more aspects of embodiments of the present disclosure are directed to a rechargeable lithium battery that densifies a negative electrode while suppressing an increase in thickness and a decrease in lifespan of the battery.

[0006] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0007] According to one or more embodiments of the present disclosure, a rechargeable lithium battery includes: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte, wherein the negative electrode has a composite density of at least 1.7 g / cc (grams per cubic centimeter), and the electrolyte includes: a lithium salt; a non-aqueous organic solvent; a first additive represented by Formula 1; a second additive represented by Formula 2; and a third additive represented by Formula 3:

[0008] Formula 1

[0009] R 1 -OR 2

[0010] In formula 1,

[0011] R 1 and R 2 Each is independently fluorine or a fluoroalkyl group having 1 to 10 carbon atoms;

[0012] Formula 2

[0013]

[0014] In formula 2,

[0015] R 3 and R 4 are each independently fluorine or a fluoroalkyl group having 1 to 10 carbon atoms; and

[0016] Formula 3

[0017]

[0018] In formula 3,

[0019] R 5 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and

[0020] x, y and z are each independently an integer of 1-20.

[0021] According to one or more embodiments, a rechargeable lithium battery may densify a negative electrode while suppressing an increase in thickness and a decrease in lifespan of the rechargeable lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other aspects, features and advantages of certain embodiments of the present disclosure will be more apparent from the following description in conjunction with the accompanying drawings.

[0023] Figure 1 to Figure 4 Each is a schematic diagram illustrating a rechargeable lithium battery according to one or more embodiments of the present disclosure.

[0024] Description of Reference Numerals

[0025] 100: Rechargeable lithium battery 10: Positive electrode

[0026] 11: Positive electrode lead lug 12: Positive electrode terminal

[0027] 20: Negative electrode 21: Negative electrode lead lug

[0028] 22: Negative electrode terminal 30: Separator

[0029] 40: electrode assembly 50: shell

[0030] 60: Sealing member 70: Electrode terminal piece

[0031] 71: Positive electrode terminal tab 72: Negative electrode terminal tab DETAILED DESCRIPTION

[0032] Hereinafter, one or more embodiments of the present disclosure will be described in detail. However, these embodiments are presented by way of example only, and the embodiments of the present disclosure are not limited thereto, and the present disclosure is limited only by the scope of the claims and their equivalents.

[0033] Unless otherwise specified herein, when a layer, film, region, plate, etc. is referred to as being "on one another" or "on another", this includes not only when it is "directly on one another" or "directly on one another", but also when there is another portion (e.g., an intervening portion) therebetween. In contrast, "directly on..." may refer to the absence of another layer, film, region, plate, etc. between a layer, film, region, plate, etc. and another layer, film, region, plate. For example, "directly on..." may refer to two layers or two members being disposed without using an additional member (such as a bonding member) therebetween.

[0034] In the present disclosure, unless otherwise indicated, the singular may include the plural. For example, the singular forms "a", "an", "one", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. In addition, unless otherwise indicated, "A or B" or "A and / or B" may mean "including A, including B, or including A and B". In addition, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure".

[0035] As used herein, "combinations thereof" may refer to mixtures, laminates, composites, copolymers, alloys, blends, and / or reaction products of the components.

[0036] As used herein, the term "negative electrode composite density", "composite density of negative electrode" or "composite density" may refer to a value calculated by dividing the weight of components (active material (e.g., negative electrode active material), conductive material, binder, etc.) in a negative electrode or a positive electrode other than the current collector by the volume of the components.

[0037] Unless otherwise defined in a formula of the present disclosure, if (for example, when) a chemical bond is not drawn at a position where a chemical bond should be drawn, it means that a hydrogen is bonded to the position.

[0038] In the present disclosure, unless otherwise defined, "*" means moieties connected to the same or different atoms or chemical formulas.

[0039] As used herein, "fluoroalkyl" refers to an alkyl group in which some or all of the hydrogens are replaced by fluorine.

[0040] As used herein, "perfluoroalkyl" means an alkyl group in which all hydrogens are replaced by fluorine.

[0041] Rechargeable lithium battery

[0042] According to one or more embodiments of the present disclosure, a rechargeable lithium battery may include: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte, wherein the negative electrode has a composite density of at least 1.7 g / cc, and the electrolyte includes: a lithium salt; a non-aqueous organic solvent; a first additive represented by Formula 1; a second additive represented by Formula 2; and a third additive represented by Formula 3:

[0043] Formula 1

[0044] R 1 -OR 2

[0045] In formula 1,

[0046] R 1 and R 2 Each is independently fluorine or a fluoroalkyl group having 1 to 10 carbon atoms;

[0047] Formula 2

[0048]

[0049] In formula 2,

[0050] R 3 and R 4 are each independently fluorine or a fluoroalkyl group having 1 to 10 carbon atoms; and

[0051] Formula 3

[0052]

[0053] In formula 3,

[0054] R 5 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and

[0055] x, y and z are each independently an integer of 1-20.

[0056] Each of the first to third additives functions as a surfactant having both a hydrophilic group and a hydrophobic group in one molecule (eg, simultaneously).

[0057] The first additive may include an ether group at its center (e.g., as a core structure in the molecular structure of the first additive), with fluorine atoms or fluoroalkyl groups having 1 to 10 carbon atoms (e.g., C1-C10 fluoroalkyl groups) attached to the sides, wherein the ether group is hydrophilic and the fluorine atoms or fluoroalkyl groups having 1 to 10 carbon atoms are hydrophobic.

[0058] The second additive may include a keto group at the center of the molecular structure of the second additive (e.g., as a core structure in the molecular structure of the second additive), and a fluorine atom or a fluoroalkyl group having 1 to 10 carbon atoms (e.g., a C1-C10 fluoroalkyl group) on the side. Here, the keto group is hydrophilic, and the fluorine atom or the fluoroalkyl group having 1 to 10 carbon atoms is hydrophobic.

[0059] The third additive may include *-[O-CH(R 5 )-CH2] y -* block (as the core structure in the molecular structure of the third additive) and *-[O-CH2-CH2] x -*block and *-[O-CH2-CH2] z -* block, where *-[O-CH(R 5 )-CH2] y -* block is a hydrophobic block, and *-[O-CH2-CH2] x -*block and *-[O-CH2-CH2] z -* blocks are each a hydrophilic block.

[0060] Therefore, if (for example, when) an electrolyte containing the first to third additives at the same time is used, wettability to the positive electrode and the negative electrode is improved, and lithium cations (Li + ) can be uniformly (e.g., substantially uniformly) formed at the interface between the positive electrode and the electrolyte, and a stable solid electrolyte interface (SEI) film can be formed at the interface between the negative electrode and the electrolyte, and the precipitation of lithium dendrites is suppressed.

[0061] Therefore, by using an electrolyte including the first to third additives simultaneously, the negative electrode can be densified to a composite density of 1.7 g / cc or more while suppressing an increase in thickness and a decrease in lifespan of a rechargeable lithium battery (eg, a battery cell).

[0062] Hereinafter, a rechargeable lithium battery according to one or more embodiments of the present disclosure will be described in more detail.

[0063] Composite density of negative electrode

[0064] A known rechargeable lithium battery in the art uses a negative electrode having a composite density of less than 1.7 g / cc, while a rechargeable lithium battery according to one or more embodiments of the present disclosure uses a negative electrode having a composite density equal to or greater than 1.7 g / cc.

[0065] The upper limit of the composite density of the negative electrode is not particularly limited, but may be 2.0 g / cc or less, 1.9 g / cc or less, or 1.8 g / cc or less.

[0066] Charging upper limit voltage

[0067] In the rechargeable lithium battery according to one or more embodiments of the present disclosure, by using an electrolyte simultaneously including the first to third additives, an increase in thickness and a decrease in lifespan of the rechargeable lithium battery may be suppressed even at a high voltage.

[0068] In one or more embodiments, the rechargeable lithium battery may have a charge upper limit voltage of 4.4V or higher.

[0069] First Additive

[0070] In formula 1, R 1 and R 2 Each independently may be fluorine or a fluoroalkyl group having 1 to 10 carbon atoms.

[0071] In one or more embodiments, R 1 It may be a fluoroalkyl group having 2 carbon atoms (eg, a fluorinated ethyl group).

[0072] In one or more embodiments, R 2 It may be a fluoroalkyl group having 3 carbon atoms (eg, a fluorinated propyl group).

[0073] In one or more embodiments, the first additive may be represented by Formula 1-1:

[0074] Formula 1-1

[0075]

[0076] In formula 1-1, R 11 ~R 15 can be independently hydrogen or fluorine, wherein R 11 ~R 15 At least one of is fluorine; and R 21 ~R 27 can be independently hydrogen or fluorine, wherein R 21 ~R 27 At least one of them is fluorine.

[0077] A representative example of the first additive may be an additive represented by Formula 1-1-1:

[0078] Formula 1-1-1

[0079]

[0080] Second additive

[0081] In formula 2, R 3 and R 4Each independently may be fluorine or a fluoroalkyl group having 1 to 10 carbon atoms.

[0082] In one or more embodiments, R 3 It may be a fluoroalkyl group having 2 carbon atoms (eg, a perfluoroalkyl group having 2 carbon atoms) (eg, a partially or completely fluorinated ethyl group).

[0083] In one or more embodiments, R 4 It may be a fluoroalkyl group having 3 carbon atoms (eg, a perfluoroalkyl group having 3 carbon atoms) (eg, a partially or fully fluorinated propyl group).

[0084] In one or more embodiments, the second additive may be represented by Formula 2-1:

[0085] Formula 2-1

[0086]

[0087] In formula 2-1, R 31 ~R 35 can be independently hydrogen or fluorine, wherein R 31 ~R 35 At least one of is fluorine; and R 41 ~R 47 can be independently hydrogen or fluorine, wherein R 41 ~R 47 At least one of them is fluorine.

[0088] Representative examples of the second additive may include an additive represented by Formula 2-1-1:

[0089] Formula 2-1-1

[0090]

[0091] The third additive

[0092] In formula 3, R 5 It may be hydrogen or an alkyl group having 1 to 10 carbon atoms.

[0093] In one or more embodiments, R 5 It may be methyl.

[0094] In Formula 3, x, y and z may each independently be an integer of 1 to 20.

[0095] In one or more embodiments, the ratio of x:y (ie, molar ratio) may be 10:1 to 1:10, 5:1 to 1:5, or 3:1 to 1:3. The ratio of y:z (ie, molar ratio) may be 10:1 to 1:10, 5:1 to 1:5, or 3:1 to 1:3.

[0096] In one or more embodiments, the weight average molecular weight of the third additive may be 500 g / mol to 10,000 g / mol, 700 g / mol to 8,000 g / mol, or 1,000 g / mol to 2,000 g / mol. The weight average molecular weight may be measured by gel permeation chromatography (GPC).

[0097] If (for example, when) the weight average molecular weight of the third additive is greater than 10,000 g / mol, the viscosity of the electrolyte containing the third additive may be excessively increased, and the wettability to the positive electrode and the negative electrode may be reduced. On the other hand, if (for example, when) the weight average molecular weight of the third additive is less than 500 g / mol, its effectiveness as a surfactant may be minimal.

[0098] Representative examples of the third additive may include an additive represented by Formula 3-1:

[0099] Formula 3-1

[0100]

[0101] The third additive represented by Formula 3-1 is poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) ((poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol), PEG-b-PPG-b-PEG).

[0102] In Formula 3-1, the definitions of x, y, and z may each be the same as described in Formula 3.

[0103] Contents of the first to third additives

[0104] According to one or more embodiments of the present disclosure, the amount of the first additive may be in the range of about 1 wt % to about 10 wt %, about 1 wt % to about 7 wt %, or about 1 wt % to about 5 wt % based on 100 wt % of the total amount of the electrolyte.

[0105] If (for example, when) the content of the first additive exceeds the above range, the viscosity of the electrolyte containing the first additive may be excessively increased, and the wettability to the positive electrode and the negative electrode may be greatly reduced. On the other hand, if (for example, when) the content (for example, amount) of the first additive is lower than the above range and is included in a small amount, its effectiveness as a surfactant may be minimal.

[0106] The amount of the second additive may be in the range of about 1 wt % to about 10 wt %, about 1 wt % to about 7 wt %, or about 1 wt % to about 5 wt % based on 100 wt % of the total amount of the electrolyte.

[0107] If (for example, when) the content of the second additive exceeds the above range, the viscosity of the electrolyte containing the second additive may be excessively increased, and the wettability to the positive electrode and the negative electrode may be greatly reduced. On the other hand, if (for example, when) the content (for example, amount) of the second additive is lower than the above range and is included in a small amount, its effectiveness as a surfactant may not be significant.

[0108] The amount of the third additive may be in the range of about 1 wt % to about 10 wt %, about 1 wt % to about 7 wt %, or about 1 wt % to about 5 wt % based on 100 wt % of the total amount of the electrolyte.

[0109] If (for example, when) the content of the third additive exceeds the above range, the viscosity of the electrolyte containing the third additive may be excessively increased, and the wettability to the positive electrode and the negative electrode may be reduced. On the other hand, if (for example, when) the content (for example, amount) of the third additive is lower than the above range and is included in a small amount, its effectiveness as a surfactant may not be significant.

[0110] In one or more embodiments, the second additive may be 1 to 100 parts by weight, and the third additive may be 1 to 100 parts by weight, per 10 parts by weight of the first additive.

[0111] In one or more embodiments, the second additive may be 5 to 20 parts by weight, and the third additive may be 5 to 20 parts by weight, per 10 parts by weight of the first additive.

[0112] Within the above range, the effects of the first to third additives can be synergistic and coordinated.

[0113] Non-aqueous organic solvents

[0114] The non-aqueous organic solvent serves as a medium through which ions participating in an electrochemical reaction in a rechargeable lithium battery (eg, a battery cell) can migrate.

[0115] The non-aqueous organic solvent may include a carbonate-based solvent, an ester-based solvent, an ether-based solvent, a ketone-based solvent, an alcohol-based solvent, an aprotic solvent, or (eg, any appropriate) combinations thereof.

[0116] 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, propionate solvents (e.g., methyl propionate, ethyl propionate, or propyl propionate), decanoic acid lactone, mevalonate lactone, valerolactone, caprolactone, etc. Ether solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. In one or more embodiments, ketone solvents such as cyclohexanone may be used. Alcohol solvents may include ethanol, isopropanol, etc., and aprotic solvents may include: nitriles, such as R-CN (wherein R is a linear, branched or cyclic hydrocarbon group having 2 to 20 carbon atoms, and may include a double bond, an aromatic ring or an ether group); amides, such as dimethylformamide; dioxolanes, such as 1,3-dioxolane, 1,4-dioxolane, etc.; and / or cyclopentane sulfone.

[0117] The nonaqueous organic solvent may be used alone or as a mixture of two or more thereof.

[0118] In one or more embodiments, the non-aqueous organic solvent may include a carbonate-based solvent and a propionate-based solvent.

[0119] The content of the propionate-based solvent may be at least 70% by volume relative to 100% by volume of the total amount (eg, total volume) of the non-aqueous organic solvent. As such, high voltage and / or high temperature characteristics of a rechargeable lithium battery may be improved.

[0120] In one or more embodiments, the non-aqueous organic solvent may be a mixture of ethylene carbonate (EC), propylene carbonate (PC), and propyl propionate (PP).

[0121] Lithium salts

[0122] The lithium salt may be a substance soluble in a non-aqueous organic solvent, and serves as a lithium ion source in a rechargeable lithium battery, ensures basic operations of the rechargeable lithium battery, and promotes migration of lithium ions between a positive electrode and a negative electrode.

[0123] In one or more embodiments, LiPF6 may be used as the lithium salt.

[0124] The concentration of the lithium salt may be in the range of 0.1M to 2.0M.

[0125] Positive electrode active material

[0126] As the positive electrode active material, a compound capable of reversibly intercalating and deintercalating lithium (reversible intercalation compound) may be used. In one or more embodiments, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0127] 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 lithium nickel manganese-based oxides, or any combination thereof.

[0128] In one or more embodiments, a composite compound represented by any one of the following chemical formulas (eg, selected from any one of the following chemical formulas) may be used. a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L1 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 O 2( 0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b Gb 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).

[0129] In the above chemical formula, A may be nickel (Ni), cobalt (Co), manganese (Mn), or (e.g., any suitable) combination thereof; X may be aluminum (Al), Ni, Co, Mn, chromium (Cr), iron (Fe), magnesium (Mg), strontium (Sr), vanadium (V), a rare earth element, or (e.g., any suitable) combination thereof; D may be oxygen (O), fluorine (F), sulfur (S), phosphorus (P), or (e.g., any suitable) combination thereof; G may be Al, Cr, Mn, Fe, Mg, lanthanum (La), cerium (Ce), Sr, V, or (e.g., any suitable) combination thereof; and L1 may be Mn, Al, or a combination thereof.

[0130] In one or more embodiments, the positive electrode active material may be a high nickel-based positive electrode active material: per 100 mol % of the metal other than lithium in the lithium transition metal composite oxide, the nickel content (e.g., amount) is at least 80 mol %, at least 85 mol %, at least 90 mol %, at least 91 mol % or at least 94 mol % and not more than 99 mol %. The high nickel-based positive electrode active material can achieve high capacity, which can be applied to high capacity, high density rechargeable lithium batteries.

[0131] In one or more embodiments, the positive electrode active material may include, for example, a lithium nickel-based oxide represented by Formula 11, a lithium cobalt-based oxide represented by Formula 12, a lithium iron phosphate-based compound represented by Formula 13, a cobalt-free lithium nickel manganese-based oxide represented by Formula 14, or any combination thereof.

[0132] Formula 11

[0133] Li a1 Ni x1 M1 y1 M2 z1 O 2-b1 X b1

[0134] In 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, wherein M1 and M2 may each independently be one or more elements selected from the group consisting of aluminum (Al), boron (B), barium (Ba), calcium (Ca), cerium (Ce), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), niobium (Nb), silicon (Si), tin (Sn), strontium (Sr), titanium (Ti), vanadium (V), tungsten (W) and zirconium (Zr), and X may be one or more elements selected from the group consisting of F, P and S.

[0135] In some embodiments, in Formula 11, 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.

[0136] Formula 12

[0137] Li a2 Co x2 M3 y2 O 2-b2 X b2

[0138] In 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, wherein M3 may be one or more elements selected from the group consisting of aluminum (Al), boron (B), barium (Ba), calcium (Ca), cerium (Ce), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), silicon (Si), tin (Sn), strontium (Sr), titanium (Ti), vanadium (V), tungsten (W), yttrium (Y), zinc (Zn) and zirconium (Zr), and X may be one or more elements selected from the group consisting of F, P and S.

[0139] Formula 13

[0140] Li a3 Fe x3 M4 y3 PO 4-b3 X b3

[0141] In Formula 13, where 0.9 ≤ a3 ≤ 1.8, 0.6 ≤ x3 ≤ 1, 0 ≤ y3 ≤ 0.4, 0.9 ≤ x3 + y3 ≤ 1.1, and 0 ≤ b3 ≤ 0.1, M4 can be one or more elements selected from the group consisting of: 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 can be one or more elements selected from the group consisting of F, P, and S.

[0142] Formula 14

[0143] Li a4 Ni x4 Mn y4 M5 z4 O 2-b4 X b4

[0144] In Formula 14, where 0.9 ≤ a4 ≤ 1.8, 0.8 ≤ x4 < 1, 0 < y4 ≤ 0.2, 0 ≤ z4 ≤ 0.2, 0.9 ≤ x4 + y4 + z4 ≤ 1.1, and 0 ≤ b4 ≤ 0.1, where M5 can be one or more elements selected from the group consisting of: Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X can be one or more elements selected from the group consisting of F, P, and S.

[0145] In one or more embodiments of the present disclosure, the electrolyte in one or more embodiments described herein can particularly or significantly improve the high voltage and / or high temperature characteristics of a battery having a lithium cobalt oxide represented by Formula 12.

[0146] The positive electrode for a rechargeable lithium battery can 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 can include a positive electrode active material (e.g., a positive electrode active material in particulate form), and can further include a binder and / or a conductive material and / or a coating material.

[0147] In one or more embodiments, the positive electrode can further include an additive that can act as a sacrificial positive electrode material.

[0148] Based on the total weight of 100 wt% of the positive electrode active material layer, the content (e.g., amount) of the positive electrode active material can be in the range of about 90 wt% to about 99.5 wt%, and based on the total weight of 100 wt% of the positive electrode active material layer, the content (e.g., amount) of each of the binder and the coating material can be in the range of about 0.5 wt% to about 5 wt%.

[0149] The binder is used to bind the positive electrode active material particles to each other and also to bind the positive electrode active material to the positive electrode current collector. Non-limiting 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, resin, polyester resin, nylon, etc.

[0150] The conductive material can be used to impart conductivity to the electrode, and can be any conductive material that does not cause chemical changes in the constructed rechargeable lithium battery. Non-limiting examples of the conductive material may include: natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black; carbon-based materials such as carbon fibers, carbon nanofibers, carbon nanotubes, etc.; metal-based materials in the form of metal powders or metal fibers containing copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; and / or mixtures thereof.

[0151] In one or more embodiments, an Al (aluminum) foil may be used as the positive electrode current collector, but embodiments of the present disclosure are not limited thereto.

[0152] Negative electrode active material

[0153] Examples of the negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, and / or a transition metal oxide.

[0154] The material capable of reversibly inserting / deinserting lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or (for example, any appropriate) combination thereof. Non-limiting examples of crystalline carbon may include graphite in an amorphous form, a plate form, a flake form, a spherical form, or a fiber form, such as natural graphite or artificial graphite, and non-limiting examples of amorphous carbon may include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0155] As an alloy of lithium metal, an alloy of 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 can be used.

[0156] As a material capable of doping and dedoping lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiO x(0 < x ≤ 2), Si-Q alloy (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 combinations thereof) or any combination thereof. The Sn-based negative electrode active material can be Sn, SnO k (0 < k ≤ 2) (e.g., SnO2), Sn-based alloy, or (e.g., any suitable) combination thereof.

[0157] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one or more embodiments, the silicon-carbon composite can be in the form of silicon particles and an amorphous carbon coating coated on the surface of each silicon particle. For example, in one or more embodiments, the silicon-carbon composite can include secondary particles (cores) in which silicon primary particles are assembled (e.g., aggregated) and an amorphous carbon coating (shells) located on the surface of the secondary particles. Amorphous carbon can also be located between the silicon primary particles such that, for example, each silicon primary particle is coated with amorphous carbon. The secondary particles can be dispersed in an amorphous carbon matrix.

[0158] In one or more embodiments, the silicon-carbon composite can further include crystalline carbon. For example, in some embodiments, the silicon-carbon composite in the form of particles can include: a core including crystalline carbon and silicon particles; and an amorphous carbon coating located on the surface of the core.

[0159] In one or more embodiments, the Si-based negative electrode active material or the Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material.

[0160] The negative electrode for a rechargeable lithium battery can include a negative electrode current collector and a negative electrode active material layer on (e.g., disposed on) the negative electrode current collector. The negative electrode active material layer includes a negative electrode active material (e.g., the negative electrode active material in the form of particles), and can further include a binder and / or a conductive material and / or a coating material.

[0161] In one or more embodiments, based on the total weight of the negative electrode active material layer of 100 wt%, the negative electrode active material layer can include about 90 wt% to about 99 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and 0 wt% to about 5 wt% of the conductive material.

[0162] The binder is used to bond the negative electrode active material particles to each other and also bond the negative electrode active material to the negative electrode current collector. The binder can be a non-aqueous (e.g., insoluble in water) binder, an aqueous (e.g., soluble in water) binder, a dry binder, or (e.g., any suitable) combination thereof.

[0163] 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, or any combination thereof.

[0164] The water-based binder can be a rubber-based binder or a polymer resin binder. The rubber-based binder can be selected from styrene-butadiene rubber (SBR), acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber and / or a combination thereof. The polymer resin binder can be selected from polyphosphazene, poly(methyl)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (methyl)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol and / or a combination thereof.

[0165] In some embodiments, when an aqueous binder is used as a binder in the negative electrode active material layer, the binder may further include a cellulose compound capable of imparting viscosity. The cellulose compound may include one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0166] The dry binder can be a fiberized polymer material, such as polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or (eg, any suitable) combinations thereof.

[0167] The conductive material used to impart conductivity to the negative electrode may be any conductive material that does not undergo chemical modification in the constructed rechargeable lithium battery. Non-limiting examples of conductive materials may include natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black; carbon-based materials such as carbon fibers, carbon nanofibers, carbon nanotubes, etc.; 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.

[0168] 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 combinations thereof.

[0169] Diaphragm

[0170] According to the type of rechargeable lithium battery, in one or more embodiments, a separator may also be present between the positive electrode and the negative electrode. The separator may be 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 polyethylene / polyethylene / polypropylene three-layer separator, etc.

[0171] The separator may include a porous substrate and a coating layer located on one or both sides (eg, two opposite sides) of the porous substrate, the coating layer including an organic material, an inorganic material, or a combination thereof.

[0172] The porous substrate can be made of the following: polyolefins (such as polyethylene, polypropylene), polyesters (such as polyethylene terephthalate, 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 / or polytetrafluoroethylene (e.g., Teflon), or polymer films formed from copolymers or mixtures of two or more of these polymers.

[0173] The organic material may include a polyvinylidene fluoride-based polymer and / or a (meth)acrylic-based polymer.

[0174] The inorganic material may include, but is not limited to, inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0175] The organic material and the inorganic material may be present as a mixture in one coating layer, or may be present in the form of a coating layer including an organic material and a coating layer including an inorganic material laminated together.

[0176] Rechargeable lithium battery

[0177] The rechargeable lithium batteries may be classified into a cylindrical shape, a prismatic shape, a pouch shape, a coin shape, etc., based on their shapes. Figure 1 to Figure 4 Each is a schematic diagram illustrating a rechargeable lithium battery according to one or more embodiments, wherein Figure 1 Explain cylindrical rechargeable lithium battery, Figure 2 A prismatic rechargeable lithium battery is described, and Figure 3 and Figure 4 Each illustrates a rechargeable lithium battery having a pouch type shape. Figure 1 to Figure 4 , the rechargeable lithium battery 100 may include: an electrode assembly 40 having a separator 30 disposed between a positive electrode 10 and a negative electrode 20; and a housing 50 in which the electrode assembly 40 is housed. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte (not shown). In some embodiments, the rechargeable lithium battery 100 may include a sealing member 60 that seals the housing 50, such as Figure 1 In some embodiments, Figure 2As shown in , the rechargeable lithium battery 100 may include a positive electrode lead tab 11 and a positive electrode terminal 12, a negative electrode lead tab 21 and a negative electrode terminal 22. In some embodiments, as Figure 3 and Figure 4 As shown in FIG. 1 , the rechargeable lithium battery 100 may include electrode tabs 70 , ie, a positive electrode tab 71 and a negative electrode tab 72 , which serve as an electrical path for guiding current formed in the electrode assembly 40 to the outside.

[0178] The rechargeable lithium battery according to one or more embodiments of the present disclosure may be applied to automobiles, mobile phones, and / or various other forms of electrical devices, and the embodiments of the present disclosure are not limited thereto.

[0179] Hereinafter, examples and comparative examples of the present disclosure will be described in more detail. However, the following examples are merely exemplary embodiments of the present disclosure, and embodiments of the present disclosure are not limited to the following examples.

[0180] Examples and Comparative Examples

[0181] The electrolyte and rechargeable lithium battery were prepared as described below.

[0182] Example 1

[0183] (1) Preparation of electrolyte

[0184] The electrolyte was prepared by dissolving 1.3 M LiPF6 in a non-aqueous organic solvent including a mixture of ethylene carbonate (EC), propylene carbonate (PC) and propyl propionate (PP) in a volume ratio of 10:15:75, and adding 1 wt % of a first additive, 1 wt % of a second additive and 1 wt % of a third additive (based on 100 wt % of the total weight of the electrolyte).

[0185] The first additive is represented by Formula 1-1-1, the second additive is represented by Formula 2-1-1, and the third additive is represented by Formula 3-1:

[0186] Formula 1-1-1

[0187]

[0188] 1,1,2,2-Tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (CAS No.: 16627-68-2)

[0189] Formula 2-1-1

[0190]

[0191] Perfluoro(2-methyl-3-pentanone) (CAS No.: 756-13-8)

[0192] Formula 3-1

[0193]

[0194] Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-b-PPG-b-PEG. CAS No.: 9003-11-6, x=1-20, y=1-20, z=1-20, weight average molecular weight: 1,100 g / mol)

[0195] (2) Manufacturing of rechargeable lithium batteries

[0196] 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 96:3:1, respectively, and dispersed in N-methylpyrrolidone to prepare a positive electrode active material slurry.

[0197] The positive electrode active material slurry was coated on a 15 micrometer (μm) thick Al foil, dried at 100° C., and roll-pressed to prepare a positive electrode.

[0198] Artificial graphite was used as a negative electrode active material, and a negative electrode active material slurry was prepared by mixing the negative electrode active material with a styrene-butadiene rubber binder and carboxymethyl cellulose at a weight ratio of 98:1:1, respectively, and dispersing them in distilled water.

[0199] The negative electrode active material slurry was coated on a 10 μm thick Cu foil, dried at 100° C., and pressed to prepare a negative electrode. At this time, the negative electrode was made to have a composite density of 1.7 g / cc.

[0200] An electrode assembly was prepared by assembling a positive electrode and a negative electrode with a separator made of polyethylene having a thickness of 10 μm, and a rechargeable lithium battery (eg, a battery cell) was prepared by injecting an electrolyte.

[0201] Example 2

[0202] An electrolyte and a rechargeable lithium battery (eg, a battery cell) were each prepared in substantially the same manner as in Example 1, except that 1 wt % of the first additive, 2 wt % of the second additive, and 1 wt % of the third additive were each added during the preparation of the electrolyte.

[0203] Example 3

[0204] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that 1 wt % of the first additive, 1 wt % of the second additive, and 2 wt % of the third additive were each added in the prepared electrolyte.

[0205] Example 4

[0206] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that 2 wt % of the first additive, 2 wt % of the second additive, and 2 wt % of the third additive were each added in the prepared electrolyte.

[0207] Example 5

[0208] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that 5 wt % of the first additive, 5 wt % of the second additive, and 5 wt % of the third additive were each added in the prepared electrolyte.

[0209] Example 6

[0210] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that 2 wt % of the first additive, 2 wt % of the second additive, and 2 wt % of the third additive were each added during the preparation of the electrolyte, and the negative electrode was prepared so that its composite density was 1.75 g / cc.

[0211] Example 7

[0212] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that 2 wt % of the first additive, 2 wt % of the second additive and 2 wt % of the third additive were each added during the preparation of the electrolyte, and the negative electrode was prepared so that its composite density was 1.8 g / cc.

[0213] Comparative Example 1

[0214] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that no additive was added during the preparation of the electrolyte, and the composite density of the prepared negative electrode was 1.65 g / cc.

[0215] Comparative Example 2

[0216] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that no additive was added during the preparation of the electrolyte, and the composite density of the prepared negative electrode was 1.67 g / cc.

[0217] Comparative Example 3

[0218] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that no additive was added during the preparation of the electrolyte, and the composite density of the prepared negative electrode was 1.7 g / cc.

[0219] Comparative Example 4

[0220] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that the second additive and the third additive were not added during the preparation of the electrolyte, 1 wt % of the first additive was added, and the composite density of the prepared negative electrode was 1.7 g / cc.

[0221] Comparative Example 5

[0222] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that the first additive and the third additive were not added during the preparation of the electrolyte, 1 wt % of the second additive was added, and the composite density of the prepared negative electrode was 1.7 g / cc.

[0223] Comparative Example 6

[0224] An electrolyte and a rechargeable lithium battery were each prepared in substantially the same manner as in Example 1, except that the first additive and the second additive were not added during the preparation of the electrolyte, 1 wt % of the third additive was added, and the composite density of the prepared negative electrode was 1.7 g / cc.

[0225] Evaluate

[0226] The negative electrode and the rechargeable lithium battery were each evaluated using the following methods.

[0227] Evaluation 1: Impregnation of negative electrode with electrolyte

[0228] The negative electrode according to Example 1 was prepared as a sample of L×W=3 cm×4 cm. 1 g of the electrolyte according to Example 1 was dropped on the sample and left for 1 minute. Then, the amount of the electrolyte impregnated in the sample in 100 wt % of the electrolyte dropped on the sample was evaluated on a scale of 0 to 5 according to the following criteria, and the evaluation results are shown in Table 1.

[0229] 0: The amount of the electrolyte immersed in the sample is equal to or greater than 0 wt % and less than 10 wt %.

[0230] 1: The amount of the electrolyte immersed in the sample is equal to or greater than 10 wt % and less than 20 wt %.

[0231] 2: The amount of the electrolyte immersed in the sample is equal to or greater than 20 wt % and less than 40 wt %.

[0232] 3: The amount of the electrolyte immersed in the sample is equal to or greater than 40 wt % and less than 60 wt %.

[0233] 4: The amount of the electrolyte immersed in the sample is equal to or greater than 60 wt % and less than 80 wt %.

[0234] 5: The amount of the electrolyte immersed in the sample is equal to or greater than 80 wt % and equal to or less than 100 wt %.

[0235] Examples 2 to 7 and Comparative Examples 1 to 6 were each evaluated in substantially the same manner, and the evaluation results are shown in Table 1 below.

[0236] Table 1

[0237]

[0238] Evaluation 2: Evaluation of room temperature charge / discharge cycle characteristics

[0239] The rechargeable lithium battery was subjected to 400 charge and discharge cycles at room temperature (eg, 25° C.), 2.0 C charge (CC / CV, 4.47 V, 0.025 C cutoff) / 1.0 C discharge (CC, 3 V cutoff).

[0240] The thickness growth 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 below.

[0241] Equation 1

[0242] Thickness increase rate (%) = {(total thickness after 400 cycles) - (total thickness after 1 cycle)} / (total thickness after 1 cycle) × 100

[0243] In Equation 1, “full thickness” means the thickness of the rechargeable lithium battery measured after each cycle of charging to SOC 100% (a state of charging to 100% charge capacity when the total charge capacity of the battery is set to 100%).

[0244] Equation 2,

[0245] Capacity retention rate (%) = (discharge capacity after 400 cycles / discharge capacity after 1 cycle) × 100

[0246] Table 2

[0247]

[0248]

[0249] Referring to Tables 1 and 2, when an electrolyte without any additives is used (Comparative Examples 1 to 3), increasing the composite density of the negative electrode from 1.65 g / cc to 1.7 g / cc reduces the impregnation of the negative electrode by the electrolyte, increases the thickness of the rechargeable lithium battery, and reduces the life of the rechargeable lithium battery.

[0250] However, when the negative electrode has the same composite density of 1.7 g / cc, compared with using an electrolyte without any additives (Comparative Example 3), the electrolyte including the first to third additives (Examples 1 to 5) increases the impregnation of the negative electrode, the thickness growth rate of the rechargeable lithium battery during charging and discharging decreases, and the life of the rechargeable lithium battery increases.

[0251] On the other hand, if an electrolyte including only one of the first to third additives is used (Comparative Examples 4 to 6), the SEI film is unstably formed on the surface of the negative electrode, resulting in the growth of lithium dendrites, and the capacity retention rate during charge and discharge plummets. Therefore, it is beneficial and desirable to use an electrolyte containing the first to third additives.

[0252] In addition, when an electrolyte including the first to third additives at the same time is used, even if the composite density of the negative electrode is increased from 1.75 g / cc to 1.8 g / cc (Examples 6 and 7), the thickness increase and life reduction of the rechargeable lithium battery during charging and discharging are suppressed.

[0253] In the present disclosure, the terms “comprise / comprising,” “include / including,” or “has / having” are intended to indicate the presence of a certain characteristic, quantity, step, constituent element, or combination thereof, but it should be understood that the possibility of the presence or addition of one or more other characteristics, quantities, steps, constituent elements, or combinations thereof is not precluded.

[0254] The term "Group" as used herein refers to a Group of the Periodic Table of the Elements according to the International Union of Pure and Applied Chemistry ("IUPAC") 1-18 Group system.

[0255] 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 will be recognized by those of ordinary skill in the art. As used herein, the terms "about" and "approximately" also include the stated value and mean within the acceptable deviation range of the particular value determined by those of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "about" may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0256] Any numerical range set forth in this article is intended to include all sub-ranges of the same numerical precision falling within the range set forth. For example, the range of "1.0 to 10.0" is intended to include between the minimum value 1.0 set forth and the maximum value 10.0 set forth (and including 1.0 and 10.0), that is, all sub-ranges with a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. 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 herein.

[0257] The battery management system (BMS) device and / or any other related device or component according to the embodiment 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, the various components of the device may be formed on an integrated circuit (IC) chip or on a separate IC chip. In addition, 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. In addition, the various components of the device may be processes or threads running on one or more processors in one or more computing devices, executing computer program instructions and interacting with other system components to perform the various functions described herein. The computer program instructions are stored in a memory, which may be implemented in a computing device using a standard memory device, such as, for example, a random access memory (RAM). The computer program instructions may also be stored in other non-temporary computer-readable media, such as, for example, a CD-ROM or 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 various computing devices may be combined or integrated into a single computing device, or the functions of a dedicated computing device may be distributed on one or more other computing devices.

[0258] The foregoing is an explanation of some embodiments of the present disclosure and is not to be construed as a limitation of the present disclosure. Although some embodiments have been described, it is readily recognized by those skilled in the art that various modifications may be made to the embodiments without departing from the spirit and scope of the present disclosure. It will be understood that the description of features or aspects within each embodiment should generally be considered as other similar features or aspects that can be used in other embodiments, unless otherwise described. Therefore, it is obvious to those of ordinary skill in the art that the features, characteristics and / or elements described in conjunction with a particular embodiment may be used alone or in combination with the features, characteristics and / or elements described in conjunction with other embodiments, unless otherwise specifically indicated. Therefore, it should be understood that the foregoing is an explanation of each example embodiment and should not be construed as being limited to the specific embodiments disclosed herein, and various modifications to the disclosed embodiments and other exemplary embodiments are intended to be included in the spirit and scope of the present disclosure as defined by the claims and their equivalents.

Claims

1. A rechargeable lithium battery comprising: a positive electrode, including a positive electrode active material; a negative electrode, including a negative electrode active material; and Electrolyte, in, The negative electrode has a composite density of at least 1.7 g / cc, and the electrolyte comprises: Lithium salts; Non-aqueous organic solvents; A first additive represented by Formula 1; a second additive represented by Formula 2; and The third additive represented by Formula 3: Formula 1 R 1 -O-R 2 In formula 1, R 1 and R 2 Each is independently fluorine or a fluoroalkyl group having 1 to 10 carbon atoms; Formula 2 In formula 2, R 3 and R 4 are each independently fluorine or a fluoroalkyl group having 1 to 10 carbon atoms; and Formula 3 In formula 3, R 5 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and x, y and z are each independently an integer of 1 to 20.

2. The rechargeable lithium battery of claim 1, wherein the first additive is represented by Formula 1-1: Formula 1-1 In formula 1-1, R 11 ~R 15 are each independently hydrogen or fluorine, and are selected from R 11 ~R 15 At least one of is fluorine, and R 21 ~R 27 are each independently hydrogen or fluorine, and are selected from R 21 ~R 27 At least one of them is fluorine.

3. The rechargeable lithium battery of claim 2, wherein The first additive is represented by formula 1-1-1: Formula 1-1-1 4. The rechargeable lithium battery of claim 1, wherein The second additive is represented by Formula 2-1: Formula 2-1 In formula 2-1, R 31 ~R 35 are each independently hydrogen or fluorine, and are selected from R 31 ~R 35 At least one of is fluorine, and R 41 ~R 47 are each independently hydrogen or fluorine, and are selected from R 41 ~R 47 At least one of them is fluorine.

5. The rechargeable lithium battery of claim 4, wherein The second additive is represented by formula 2-1-1: Formula 2-1-1 6. The rechargeable lithium battery of claim 1, wherein In formula 3, R 5 It is methyl.

7. The rechargeable lithium battery of claim 1, wherein The weight average molecular weight of the third additive is 500 g / mol to 10,000 g / mol.

8. The rechargeable lithium battery of claim 1, wherein An amount of the first additive in the electrolyte is in a range of 1 wt % to 10 wt % based on 100 wt % of a total amount of the electrolyte.

9. The rechargeable lithium battery of claim 1, wherein The amount of the second additive in the electrolyte is in the range of 1 wt % to 10 wt % based on 100 wt % of the total amount of the electrolyte.

10. The rechargeable lithium battery of claim 1, wherein An amount of the third additive in the electrolyte is in the range of 1 wt % to 10 wt % based on 100 wt % of the total amount of the electrolyte.

11. The rechargeable lithium battery of claim 1, wherein For every 10 parts by weight of the first additive, the second additive is 1 to 100 parts by weight, and the third additive is 1 to 100 parts by weight.

12. The rechargeable lithium battery of claim 1, wherein The non-aqueous organic solvent includes carbonate solvents and propionate solvents.

13. The rechargeable lithium battery of claim 12, wherein The content of the propionate solvent is at least 70 volume % relative to 100 volume % of the total amount of the non-aqueous organic solvent.

14. The rechargeable lithium battery of claim 1, wherein The lithium salt is LiPF6.

15. The rechargeable lithium battery of claim 1, wherein The concentration of the lithium salt is 0.1M to 2.0M.

16. The rechargeable lithium battery of claim 1, 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.

17. The rechargeable lithium battery of claim 1, 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.

18. The rechargeable lithium battery of claim 1, wherein The rechargeable lithium battery has a charge upper limit voltage of 4.4V or higher.

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