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 non-aqueous organic solvent; a lithium salt; and an additive represented by Chemical Formula 1. The chemical formula 1R-L-N = C = O.

Description

TECHNICAL FIELD

[0001] One or more embodiments of the present disclosure relate to an electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the electrolyte. BACKGROUND

[0002] A rechargeable lithium battery is rechargeable, and has a high energy density of three times or more per unit weight compared to a lead storage battery, a nickel-cadmium battery, a nickel-hydrogen battery, a nickel-zinc battery, etc. The rechargeable lithium battery can also be charged at a high rate, and thus, can be commercially manufactured for a laptop computer, a cellular phone, a power tool, an electric bicycle, etc. Research on improving additional energy density has been actively conducted.

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

[0004] If such a rechargeable lithium battery is continuously charged and discharged and / or stored at a high temperature (for example, when such a rechargeable lithium battery is continuously charged and discharged and / or stored at a high temperature), a lithium salt (for example, LiPF6) in the electrolyte can react with moisture (for example, H2O) to generate undesirable hydrogen fluoride (HF), and the HF can dissolve transition metal (for example, Fe) ions from the positive electrode active material. The transition metal ions dissolved from the positive electrode active material can be deposited as a metal on a negative electrode surface after moving through the electrolyte, and react with moisture inside the rechargeable lithium battery to generate gas and / or increase resistance, thereby accelerating deterioration of the rechargeable lithium battery. SUMMARY

[0005] In one or more embodiments, by effectively removing moisture (for example, H2O) in the rechargeable lithium battery, an undesirable side reaction between a lithium salt (for example, LiPF6) and moisture (for example, H2O) can be inhibited or reduced (or the degree or occurrence of the undesirable side reaction between the lithium salt (for example, LiPF6) and the moisture (for example, H2O) can be reduced), and a side reaction with transition metal ions dissolved from the positive electrode active material can be inhibited or reduced (or the degree or occurrence of the side reaction with the transition metal ions dissolved from the positive electrode active material can be reduced), and ultimately, an electrolyte for a rechargeable lithium battery that can improve or enhance charge / discharge characteristics and / or high-temperature storage characteristics of the rechargeable lithium battery can be provided.

[0006] One or more aspects of embodiments of the present disclosure relate to a rechargeable lithium battery including an electrolyte for a rechargeable lithium battery.

[0007] Additional aspects will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the disclosure, or can be learned by practice of the presented embodiments of the disclosure.

[0008] The electrolyte for the rechargeable lithium battery can include a nonaqueous organic solvent (e.g., a water-insoluble organic solvent); a lithium salt; and an additive represented by Chemical Formula 1:

[0009] Chemical Formula 1

[0010] R-L-N=C=O.

[0011] In Chemical Formula 1, R can be a substituted or unsubstituted C3-C20 cycloalkyl; and L can be a single bond (e.g., a single covalent bond) or a substituted or unsubstituted C1-C20 alkylene.

[0012] One or more embodiments of the disclosure provide a rechargeable lithium battery, which can include a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte.

[0013] The electrolyte for the rechargeable lithium battery according to one or more embodiments can suppress or reduce a reaction between a lithium salt (e.g., LiPF6) and moisture (e.g., H2O) (or can reduce the degree or occurrence of a reaction between a lithium salt (e.g., LiPF6) and moisture (e.g., H2O)), suppress or reduce a side reaction with a transition metal ion eluted from the positive electrode active material (or can reduce the degree or occurrence of a side reaction with a transition metal ion eluted from the positive electrode active material), and ultimately improve or enhance the charge / discharge characteristics and / or high-temperature storage characteristics of the rechargeable lithium battery. BRIEF DESCRIPTION OF DRAWINGS

[0014] The above and other aspects and features of certain embodiments of the disclosure will be more apparent from the following description, taken in conjunction with the accompanying drawings, in which:

[0015] Fig. 1 to Fig. 4 Each is a schematic view to explain a rechargeable lithium battery according to one or more embodiments.

[0016] REFERENCE NUMERALS

[0017] 100: rechargeable lithium battery 10: positive electrode

[0018] 11: positive electrode lead tab 12: positive electrode terminal

[0019] 20: negative electrode 21: negative electrode lead tab

[0020] 22: negative electrode terminal 30: separator

[0021] 40: electrode assembly 50: case

[0022] 60: sealing member 70: electrode tab

[0023] 71: positive electrode tab 72: negative electrode tab DETAILED DESCRIPTION

[0024] In the foregoing, certain embodiments of the disclosure have been described and illustrated, but it is understood that the disclosure is not limited to those embodiments specifically described and that the disclosure can be readily adapted last modified, and applied to other embodiments and aspects without departing from the spirit and scope of the disclosure. In one or more embodiments, the embodiments so modified or adapted should be considered within the scope of the technical concept and aspect of one or more embodiments of the disclosure, and the modified embodiments can be within the scope of the claims of the disclosure and equivalents thereof.

[0025] As utilized herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, to the extent that the disclosure refines embodiments of the disclosure, the use of "or" means "and / or" in the case of alternative embodiments.

[0026] In the context of the disclosure and unless otherwise limited, the terms "use", "using" and "used" can be considered synonymous with the terms "utilize", "utilizing" and "utilized", respectively.

[0027] As utilized herein the terms "about" or similar terms are used as the modifier for a term or numeric value and not as an exact term, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. As used herein, "about" or "approximately" includes the recited value and means within an acceptable range of deviation for the particular value determined by one of ordinary skill in the art taking into account measurement of the value in question and the error associated with measuring that particular quantity (e.g., limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the recited value, or within ±30%, ±20%, ±10%, or ±5% of the recited value.

[0028] Any numerical range recited herein is intended to include all sub-ranges of essentially identical numbers within the recited range. For example, a range of 1.0 to 10.0 is intended to include all sub-ranges, e.g., 2.4 to 7.6, within the range of 1.0 to 10.0, and is not limited to only 1.0 to 10.0. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations, and any minimum numerical limitation recited herein is intended to include all higher numerical limitations. Accordingly, Applicant reserves the right to amend the present disclosure, including the claims, to expressly recite any sub-range of values stated herein.

[0029] As used herein, if not otherwise provided, if 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 (such as a layer, film, region, or substrate) can also be present.

[0030] As used herein, if not otherwise provided, the singular can also include the plural, unless it is clear that it is meant otherwise. Further, "A or B" can mean "A, B, or both A and B" unless otherwise indicated.

[0031] As used herein, "combinations thereof' can refer to mixtures, stacks, composites, copolymers, alloys, blends, and reaction products of ingredients.

[0032] As used herein, if no specific limitation is provided otherwise (e.g., when no specific limitation is provided otherwise), "substitution" means that at least one hydrogen atom in a compound is substituted with a substituent selected from a halogen atom (F, Cl, Br, or I), a hydroxyl group, a C1-C20 alkoxy group, a nitro group, a cyano group, an amine group, an amino group, an imine group, an azido group, a guanidine group, a hydrazine group, a hydrazone group, a carbonyl group, a carboxamide group, a thiol group, an ester group, an ether group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C6-C30 aryl group, a C3-C20 cycloalkyl group, a C3-C20 cycloalkenyl group, a C3-C20 cycloalkynyl group, a C2-C20 heterocycloalkyl group, a C2-C20 heterocycloalkenyl group, a C2-C20 heterocycloalkynyl group, or a combination thereof. The alkyl group can include a straight-chain alkyl group and / or a chain alkyl group, and the cycloalkyl group can include a cyclic alkyl group.

[0033] As used herein, if no specific limitation is provided otherwise (e.g., when no specific limitation is provided otherwise), "heterocycloalkyl group", "heterocycloalkenyl group", "heterocycloalkynyl group", and "heterocycloalkylene group" mean that at least one heteroatom of nitrogen (N), oxygen (O), sulfur (S), and phosphorus (P) is present in a ring compound of a cycloalkyl group, a cycloalkenyl group, a cycloalkynyl group, and a cycloalkylene group, respectively.

[0034] In the chemical formulae of the present specification, unless a specific limitation is provided otherwise, a hydrogen atom (H) can be bonded at a position where a chemical bond should be given but is not drawn (e.g., when a chemical bond should be given but is not drawn).

[0035] Electrolyte solution

[0036] One or more embodiments of the present disclosure provide an electrolyte solution for a rechargeable lithium battery, which can include a non-aqueous organic solvent (e.g., a water-insoluble organic solvent); a lithium salt; and an additive represented by Chemical Formula 1:

[0037] Chemical Formula 1

[0038] R-L-N=C=O.

[0039] In Chemical Formula 1, R can be a substituted or unsubstituted C3-C20 cycloalkyl group; and L can be a single bond (e.g., a single covalent bond) or a substituted or unsubstituted C1-C20 alkylene group.

[0040] The additive represented by Chemical Formula 1 can be a compound containing or including a cycloalkyl group and an isocyanate group, and the isocyanate group can react with moisture to be converted into an amine group, and simultaneously (e.g., synchronously) generate carbon dioxide (CO2). In one or more embodiments, the cycloalkyl group can increase or enhance the polarity of the additive represented by Chemical Formula 1 compared to an alkyl group, and can improve or enhance the reactivity of the isocyanate group with moisture.

[0041] In one or more embodiments, the electrolyte of one or more embodiments can suppress or reduce the reaction between a lithium salt (e.g., LiPF6) and moisture (e.g., H2O) (or can reduce the degree or occurrence of the reaction between a lithium salt (e.g., LiPF6) and moisture (e.g., H2O)), suppress or reduce the side reaction with transition metal ions eluted from the positive electrode active material (or can reduce the degree or occurrence of the side reaction with transition metal ions eluted from the positive electrode active material), and ultimately improve or enhance the charge / discharge characteristics and / or high-temperature storage characteristics of the rechargeable lithium battery by effectively removing moisture in the rechargeable lithium battery.

[0042] Hereinafter, the electrolyte according to one or more embodiments will be described in more detail.

[0043] Additive

[0044] R can be a substituted or unsubstituted C3 to C10 cycloalkyl group.

[0045] For example, R can be a substituted or unsubstituted C5 to C6 cycloalkyl group.

[0046] For example, R can be a substituent represented by Chemical Formula 2-1 or Chemical Formula 2-2:

[0047]

[0048] In Chemical Formula 2-1 and Chemical Formula 2-2, R 1 ~ R 9 may each independently be a hydrogen atom, a halogen atom, or a C1 to C20 alkyl group, and * indicates a connection site with Chemical Formula 1.

[0049] Representative examples of the additive represented by Chemical Formula 1 are as follows:

[0050]

[0051] In Chemical Formula 1-1 and Chemical Formula 1-2, R 1 ~ R 9 may each independently be a hydrogen atom, a halogen atom, or a C1 to C20 alkyl group.

[0052] For example, R 1 ~ R 9may all be hydrogen atoms.

[0053] The amount of the additive represented by Chemical Formula 1 included in the electrolyte for the rechargeable lithium battery based on a total amount of 100 wt% can be about 0.01 wt% to about 10 wt%, about 0.1 wt% to about 5 wt%, or about 0.1 wt% to about 1 wt%.

[0054] Within the above range, the effect of the additive represented by Chemical Formula 1 can be appropriately optimized or adjusted.

[0055] Additional additives

[0056] The electrolyte can further include other compounds (hereinafter referred to as "additional additives") in addition to the additive represented by Chemical Formula 1.

[0057] The additional additives can include cyclic carbonates. The cyclic carbonates can be, for example, vinyl ethylene carbonate (VEC), vinylene carbonate (VC), ethylene carbonate, derivatives thereof, or combinations thereof. The derivatives of ethylene carbonate (EC) can include, for example, fluoroethylene carbonate (FEC), difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, or the like.

[0058] In one or more embodiments, the additional additives can further include succinonitrile (SN), adiponitrile (AN), 1,3,6-hexanetricarbonitrile (HTCN), propene sulfite (PST), propane sulfite (PS), lithium tetrafluoroborate (LiBF4), lithium difluorophosphate (LiPO2F2), 2-fluorobiphenyl (2-FBP), or combinations thereof.

[0059] The amount of the additional additives included in the electrolyte for the rechargeable lithium battery based on a total amount of 100 wt% can be about 0.1 wt% to about 10 wt%, about 0.5 wt% to about 9 wt%, about 1 wt% to about 8 wt%, about 1 wt% to about 7 wt%, about 1 wt% to about 6 wt%, or about 2 wt% to about 5 wt%. If the amount of the additional additives satisfies the above range (e.g., when the amount of the additional additives satisfies the above range), the cycle life characteristics can be improved or enhanced, and the amount of gas generation and / or the resistance increase rate can be effectively or appropriately controlled without adversely affecting the rechargeable lithium battery.

[0060] Non-aqueous organic solvent

[0061] The non-aqueous organic solvent (e.g., water-insoluble organic solvent) can be used as a medium that transports ions involved in or appropriately adjusts the electrochemical reaction of the rechargeable lithium battery.

[0062] The non-aqueous organic solvent (e.g., water-insoluble organic solvent) can 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 a combination thereof.

[0063] The carbonate-based solvent can include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), or the like. The ester-based solvent can include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolide, mevalonolactone, valerolactone, caprolactone, or the like. The ether-based solvent can include dibutyl ether, tetraglyme, diglyme, glyme, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, or the like. The ketone-based solvent can include cyclohexanone. The alcohol-based solvent can include ethanol, isopropyl alcohol, or the like, and the aprotic solvent can include a nitrile such as R-CN, where R can be a C2 to C20 linear, branched, or cyclic hydrocarbon group, and can include a double bond, an aromatic ring, or an ether bond, an amide such as dimethylformamide, dioxolane such as 1,3-dioxolane or 1,4-dioxolane, sulfolane, or the like.

[0064] A single non-aqueous organic solvent (e.g., water-insoluble organic solvent) can be used or two or more non-aqueous organic solvents (e.g., water-insoluble organic solvents) can be used in combination.

[0065] In one or more embodiments, if a carbonate-based solvent is used (e.g., when a carbonate-based solvent is used), a cyclic carbonate and a chain carbonate can be mixed and used, and the cyclic carbonate and the chain carbonate can be mixed at a volume ratio of about 1:1 to about 1:9.

[0066] For example, the non-aqueous organic solvent (e.g., water-insoluble organic solvent) can be a mixture of ethylene carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC). The volume ratio thereof (e.g., the volume ratio of ethylene carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) in the mixture) can not be particularly limited. In one or more embodiments, the volume ratio thereof (e.g., the volume ratio of ethylene carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) in the mixture) can be appropriately adjusted or modified.

[0067] Lithium salt

[0068] A lithium salt dissolved in a non-aqueous organic solvent can supply lithium ions in a rechargeable lithium battery, ensure the basic operation of the rechargeable lithium battery, and / or improve the transport of lithium ions between the positive electrode and the negative electrode. Examples of the lithium salt can include one or more selected from the group consisting of LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide, LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2)(wherein x and y can each independently be an integer of 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFBOP), and lithium bis(oxalato)borate (LiBOB).

[0069] For example, LiPF6may be used as the lithium salt. For example, the lithium salt can include LiPF6.

[0070] The molar concentration of the lithium salt in the electrolyte can be about 1.0 M to about 2.0 M.

[0071] Rechargeable lithium battery

[0072] One or more embodiments of the present disclosure provide a rechargeable lithium battery that can include an electrolyte for a rechargeable lithium battery according to one or more embodiments.

[0073] By including the electrolyte for a rechargeable lithium battery according to one or more embodiments, the reaction between the lithium salt (e.g., LiPF6) and moisture (e.g., H2O) can be inhibited or reduced (or the degree or occurrence of the reaction between the lithium salt and moisture can be reduced), and the side reaction with transition metal ions eluted from the positive electrode active material can be inhibited or reduced (or the degree or occurrence of the side reaction with transition metal ions eluted from the positive electrode active material can be reduced), and ultimately, the charge / discharge characteristics and / or high-temperature storage characteristics of the rechargeable lithium battery can be improved or enhanced.

[0074] Hereinafter, the configuration or arrangement of the rechargeable lithium battery will be described, excluding the description that can be repeated above.

[0075] Positive electrode active material

[0076] The positive electrode active material can be a compound capable of intercalating / deintercalating lithium (e.g., a lithiated intercalation compound). For example, one or more types or kinds of a composite oxide of lithium and a metal selected from cobalt (Co), manganese (Mn), nickel (Ni), and combinations thereof can be used.

[0077] The complex oxide can be a lithium transition metal complex oxide, for example, can include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a lithium nickel manganese-based oxide not containing cobalt, or a combination thereof.

[0078] As an example, a compound represented by any of the following chemical formulas can be used. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G gPO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); and Li a FePO4(0.90≤a≤1.8).

[0079] In the above chemical formulas, A can be nickel (Ni), cobalt (Co), manganese (Mn), or a combination thereof; X can be aluminum (Al), Ni, Co, Mn, chromium (Cr), iron (Fe), magnesium (Mg), strontium (Sr), vanadium (V), a rare earth element, or a combination thereof; D can be oxygen (O), fluorine (F), sulfur (S), phosphorus (P), or a combination thereof; G can be Al, Cr, Mn, Fe, Mg, lanthanum (La), cerium (Ce), Sr, V, or a combination thereof; and L 1 may be Mn, Al, or a combination thereof.

[0080] For example, the positive electrode active material can be 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 lithium nickel-manganese-based oxide not containing cobalt represented by Chemical Formula 14, or a combination thereof.

[0081] Chemical Formula 11

[0082] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0083] 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 may each independently be one or more selected from 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), yttrium (Y), and zirconium (Zr), and X can be one or more selected from fluorine (F), phosphorus (P), and sulfur (S).

[0084] In Chemical 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.

[0085] Chemical Formula 12

[0086] Li a2 Co x2 M 3 y2 O 2-b2 X b2

[0087] 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 may be one or more selected from the group consisting of 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 can be one or more selected from the group consisting of F, P, and S.

[0088] Chemical Formula 13

[0089] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0090] 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 may be one or more selected from the group consisting of 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 can be one or more selected from the group consisting of F, P, and S.

[0091] Chemical Formula 14

[0092] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0093] In Chemical Formula 14, 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, M 5X 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, Y, and Zr, and X can be one or more selected from the group consisting of F, P, and S.

[0094] For example, the lithium iron phosphate-based compound represented by Chemical Formula 13 can be used as a positive electrode active material.

[0095] Iron ions eluted from the lithium iron phosphate-based compound represented by Chemical Formula 13 can have high reactivity with moisture in a rechargeable lithium battery. However, if the electrolyte according to one or more embodiments is used according to one or more embodiments (e.g., when the electrolyte according to one or more embodiments is used according to one or more embodiments), the additive represented by Chemical Formula 1 can remove or reduce moisture (e.g., the amount of moisture) in the rechargeable lithium battery, inhibit or reduce side reactions with transition metal ions eluted from the positive electrode active material (or can reduce the degree or occurrence of side reactions with transition metal ions eluted from the positive electrode active material), and ultimately, improve or enhance the charge / discharge characteristics and / or high-temperature storage characteristics of the rechargeable lithium battery.

[0096] Positive electrode

[0097] A positive electrode for a rechargeable lithium battery can 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 can include a positive electrode active material, and can further include a binder and / or an electrically conductive material (e.g., an electrically conductive material).

[0098] For example, the positive electrode can further include a component that can be used as a sacrificial positive electrode.

[0099] The amount of the positive electrode active material can be about 90 wt% to about 99 wt% based on 100 wt% of the positive electrode active material layer, and the amount of each of the binder and the electrically conductive material (e.g., the electrically conductive material) can be about 0.5 wt% to about 5 wt%.

[0100] The binder can be used to attach the positive electrode active material particles to each other well and can also be used to attach the positive electrode active material to the positive electrode current collector well. Examples of the binder can include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer including an oxirane, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc., but embodiments of the present disclosure are not limited thereto.

[0101] A conductive material (e.g., an electronically conductive material) can be used to impart electrical conductivity (e.g., electronic conductivity) to the electrode. Any suitable material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in the rechargeable lithium battery) and conducts electrons can be used in the rechargeable lithium battery. Examples of the conductive material (e.g., the electronically conductive material) can include carbon atom (C)-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials in the form of a metal powder and / or a metal fiber such as copper (Cu), nickel (Ni), aluminum (Al), silver (Ag), and the like; an electrically conductive polymer (e.g., an electronically conductive polymer) such as a polyphenylene derivative; or a mixture thereof.

[0102] The positive electrode current collector can include an Al foil, but embodiments of the present disclosure are not limited thereto.

[0103] Negative electrode active material

[0104] The negative electrode active material can be a material that reversibly intercalates / deintercalates lithium ions, a lithium metal, a lithium metal alloy, a material capable of doping / de-doping lithium, and / or a transition metal oxide.

[0105] The material that reversibly intercalates / deintercalates lithium ions can include a carbon atom (C)-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon can be graphite such as amorphous (e.g., irregularly shaped), platey (e.g., generally platey), flaky (e.g., generally flaky), spherically (e.g., generally spherical), and / or fibrous (e.g., generally fibrous) natural graphite and / or artificial graphite. The amorphous carbon can be soft carbon, hard carbon, meso-phase pitch carbonization product, calcined coke, or the like.

[0106] The lithium metal alloy can include 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.

[0107] The material capable of doping / de-doping lithium can be a silicon atom (Si)-based negative electrode active material and / or a tin atom (Sn)-based negative electrode active material. The Si-based negative electrode active material can include silicon, a silicon-carbon composite, SiO x (0 < x ≤ 2), a Si-Q alloy (where Q can be selected from an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element (excluding Si), a Group 15 element, a Group 16 element, a transition metal, a rare earth element, and a combination thereof). The Sn-based negative electrode active material can include Sn, SnO k (0 < k ≤ 2) (e.g., SnO2), a Sn-based alloy, or a combination thereof.

[0108] 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 amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite can 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 can also be between the primary silicon particles, and, for example, the primary silicon particles can be coated by the amorphous carbon. The secondary particles can be dispersed in an amorphous carbon matrix.

[0109] The silicon-carbon composite can further include crystalline carbon. For example, the silicon-carbon composite can include a core including crystalline carbon and silicon particles and an amorphous carbon coating on the surface of the core.

[0110] The Si-based negative electrode active material and / or the Sn-based negative electrode active material can be used in combination with the carbon-based negative electrode active material.

[0111] Negative electrode

[0112] The negative electrode for the rechargeable lithium battery can include a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector. The negative electrode active material layer can include a negative electrode active material, and can further include a binder and / or an electrically conductive material (e.g., an electronically conductive material).

[0113] For example, based on the total amount of the negative electrode active material layer, the negative electrode active material layer can include about 90 wt% to about 99 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and about 0 wt% to about 5 wt% of the electrically conductive material (e.g., the electronically conductive material).

[0114] 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 can include a non-aqueous binder (e.g., a water-insoluble binder), an aqueous binder (e.g., a water-soluble binder), a dry binder, or a combination thereof.

[0115] The non-aqueous binder (e.g., the water-insoluble binder) can include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or a combination thereof.

[0116] The aqueous binder (e.g., water-soluble binder) can be selected from styrene- butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile- butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoro rubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0117] If the aqueous binder (e.g., water-soluble binder) is used as a binder in the negative electrode active material layer (e.g., when the aqueous binder (e.g., water-soluble binder) is used as a binder in the negative electrode active material layer), it can further include a cellulose-based compound capable of imparting or increasing viscosity. The cellulose-based compound can include one or more selected from carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and alkali metal salts thereof. The alkali metal can be Na, K, and / or Li.

[0118] The dry binder can be a polymer material capable of fiberization, and can be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0119] The electrically conductive material (e.g., electrically conductive material) can provide electrode conductivity, and any suitable electrically conductive material can be used as the electrically conductive material, unless it causes chemical changes (e.g., undesirable chemical changes in a rechargeable lithium battery). Examples of the electrically conductive material (e.g., electrically conductive material) can 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 in the form of metal powder and / or metal fiber such as copper, nickel, aluminum, silver, etc.; electrically conductive polymers (e.g., electrically conductive polymers) such as polyphenylene derivatives; or a mixture thereof.

[0120] The negative electrode current collector can include one selected from copper foil, nickel foil, stainless steel foil, titanium foil, foamed nickel, foamed copper, a polymer substrate coated with an electrically conductive metal (e.g., electrically conductive metal), and combinations thereof, but embodiments of the present disclosure are not limited thereto.

[0121] Separator

[0122] Depending on the type or kind of the rechargeable lithium battery, a separator can exist or be provided between the positive electrode and the negative electrode. The separator can include a polyethylene separator, a polypropylene separator, a polyvinylidene fluoride separator, or a multi-layer 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.

[0123] The separator can include a porous substrate and a coating layer including an organic material, an inorganic material, or a combination thereof on one surface or both surfaces (e.g., two opposite surfaces) of the porous substrate.

[0124] The porous substrate can be a polymer film including any one of polymers selected from polyolefins such as polyethylene or polypropylene, polyesters such as polyethylene terephthalate or polybutylene terephthalate, polyacetals, polyamides, polyimides, polycarbonates, polyether ketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene ethers, cyclic olefin copolymers, polyphenylene sulfides, polyethylene naphthalate, glass fibers, and polytetrafluoroethylene (e.g., Teflon TM ) or a copolymer or mixture including two or more thereof.

[0125] The organic material can include a polyvinylidene fluoride-based polymer and / or a (meth)acrylic-based polymer.

[0126] The inorganic material can include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but embodiments of the present disclosure are not limited thereto.

[0127] The organic material and the inorganic material can be mixed in one coating layer, or a coating layer including the organic material and a coating layer including the inorganic material can be stacked.

[0128] Rechargeable lithium battery

[0129] Depending on the shape of the rechargeable lithium battery, the rechargeable lithium battery can be classified as a cylindrical, prismatic, pouch, or coin type battery, etc. Fig. 1 to Fig. 4 Each is a schematic view to explain the rechargeable lithium battery according to one or more embodiments. Fig. 1 is a schematic view to explain a cylindrical battery, Fig. 2 is a schematic view to explain a prismatic battery, and Fig. 3 and Fig. 4 Each is a schematic view to explain a pouch battery. Referring to Fig. 1 to Fig. 4 , the rechargeable lithium battery 100 can 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 can be accommodated. The positive electrode 10, the negative electrode 20, and the separator 30 can be impregnated with an electrolyte (not shown). As shown in Fig. 1 , the rechargeable lithium battery 100 can include a sealing member 60 sealing the case 50. In one or more embodiments, in Fig. 2In the middle, the rechargeable lithium battery 100 can include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. As Fig. 3 and Fig. 4 As shown in the middle, the rechargeable lithium battery 100 can include electrode tabs 70, for example, a positive electrode tab 71 and a negative electrode tab 72, serving as an electrical path to guide the current formed or provided in the electrode assembly 40 to the outside.

[0130] The rechargeable lithium battery according to one or more embodiments can be applied to a vehicle, a mobile phone, and / or one or more appropriate types or kinds of electronic devices, but embodiments of the present disclosure are not limited thereto.

[0131] Hereinafter, examples and comparative examples of the present disclosure are described. However, these examples should not be interpreted as limiting the scope of the present disclosure in any sense.

[0132] Example 1

[0133] (1) Preparation of electrolyte

[0134] LiPF6 lithium salt was mixed in a non-aqueous organic solvent in which ethylene carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 2:4:4 at a concentration of 1.5 M, and 0.5 wt% of an additive represented by Chemical Formula 1-1 was added thereto to prepare an electrolyte.

[0135] Chemical Formula 1-1: Cyclopentyl isocyanate (Cas No. 4747-71-1)

[0136]

[0137] In Chemical Formula 1-1, R 1 ~ R 4 are all hydrogen atoms.

[0138] Here, in the electrolyte composition, "wt%" is the electrolyte (e.g., lithium salt + non-aqueous organic solvent (e.g., water-insoluble organic solvent) + additive) based on the total amount of 100 wt%. Hereinafter, substantially the same content as above is applied.

[0139] (2) Manufacture of positive electrode

[0140] A positive electrode active material layer slurry was prepared by mixing 97.7 wt% of LiFePO4 as a positive electrode active material, 1.3 wt% of a polyvinylidene fluoride binder, and 1.0 wt% of a carbon nanotube conductive material, and coated on an aluminum foil current collector, dried and pressed to manufacture a positive electrode.

[0141] (3) Manufacture of negative electrode

[0142] A negative electrode active material layer slurry was prepared by mixing 97.5 wt% of a graphite negative electrode active material, 1.5 wt% of a carboxymethyl cellulose binder, and 1 wt% of a styrene-butadiene rubber in an aqueous solvent. A negative electrode was manufactured by coating the negative electrode active material layer slurry on a copper foil current collector, drying, and pressing.

[0143] (4) Manufacture of rechargeable lithium battery cell

[0144] A positive electrode and a negative electrode were assembled together with a 25 μm thick polyethylene separator to manufacture an electrode assembly, the electrode assembly was accommodated in a prismatic case, and an electrolyte was injected therein, to manufacture a rechargeable lithium battery cell.

[0145] Example 2

[0146] The electrolyte and rechargeable lithium battery cell according to Example 2 were manufactured in substantially the same manner as in Example 1, except that the amount of the additive represented by Chemical Formula 1-1 was changed to 1 wt%.

[0147] Example 3

[0148] The electrolyte and rechargeable lithium battery cell according to Example 3 were manufactured in substantially the same manner as in Example 1, except that the additive represented by Chemical Formula 1-2 was used instead of the additive represented by Chemical Formula 1-1:

[0149] Chemical Formula 1-2: Cyclohexyl isocyanate (Cas No. 3173-53-3)

[0150]

[0151] In Chemical Formula 1-2, R 5 ~ R 9 are each a hydrogen atom.

[0152] Example 4

[0153] The electrolyte and rechargeable lithium battery cell according to Example 4 were manufactured in substantially the same manner as in Example 1, except that the content (e.g., amount) of the additive represented by Chemical Formula 1-2 was changed to 1 wt%.

[0154] Comparative Example 1 (Reference)

[0155] The electrolyte and rechargeable lithium battery cell according to Comparative Example 1 were manufactured in substantially the same manner as in Example 1, except that the additive represented by Chemical Formula 1-1 was not used.

[0156] Comparative Example 2

[0157] An electrolyte and a rechargeable lithium battery cell according to Comparative Example 2 were manufactured in substantially the same manner as in Example 1, except that an additive represented by Chemical Formula 3 was used instead of an additive represented by Chemical Formula 1-1:

[0158] Chemical Formula 3: Isocyanato(methylsulfonyl)methane (Cas No. 1161826-12-5)

[0159]

[0160] Comparative Example 3

[0161] An electrolyte and a rechargeable lithium battery cell according to Comparative Example 3 were manufactured in substantially the same manner as in Example 1, except that an additive represented by Chemical Formula 4 was used instead of an additive represented by Chemical Formula 1-1:

[0162] Chemical Formula 4: 2-Isocyanatoethoxytrimethylsilane (Cas No. 22053-22-1)

[0163]

[0164] For reference, the type (or kind) and content (e.g., amount) of each additive in Examples 1 to 4 and Comparative Examples 1 to 3 are summarized in Table 1.

[0165] Table 1

[0166]

[0167] Evaluation Example 1: Room temperature charge / discharge characteristics

[0168] At 25℃, the rechargeable lithium battery cells according to Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to 0.33C charge (CC / CV, 3.65V, cut-off at 0.02C) / 1.0C discharge (CC, cut-off at 2.5V) for 200 cycles to calculate the capacity retention rate (CRR) according to Equation 1. The capacity retention rates of Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 2.

[0169] Equation 1

[0170] Capacity retention rate [%] = Discharge capacity after 200 cycles / Discharge capacity after 1 cycle x 100

[0171] Table 2

[0172]

[0173] Evaluation Example 2: High temperature storage characteristics

[0174] (1) DC-IR increase rate

[0175] The initial DC internal resistance (DC-IR) of the rechargeable lithium battery cells according to Examples 1 to 4 and Comparative Examples 1 to 3 was measured by ΔV / ΔI (voltage change / current change), and then, the maximum state of energy of each rechargeable lithium battery cell was brought to a fully charged state (SOC 100%), and then, the DC internal resistance of the rechargeable lithium battery cell in this state was measured after storing the rechargeable lithium battery cell at a high temperature (60°C) for 7 days to calculate the DC-IR increase rate (%) according to Equation 2, and the results are shown in Table 3.

[0176] Equation 2

[0177] DC-IR increase rate [%] = ((DC-IR after storing at a high temperature for 7 days - initial DC-IR) / initial DC-IR) x 100

[0178] (2) Gas increase rate

[0179] The amount of gas generation (initial gas generation amount) of the rechargeable lithium battery cells of Examples 1 to 4 and Comparative Examples 1 to 3 was measured in an Archimedes method after formation charging and discharging. Subsequently, after bringing the maximum state of energy of the rechargeable lithium battery cell to a fully charged state (SOC 100%) and storing the rechargeable lithium battery cell in this state at a high temperature (60°C) for 7 days, the amount of gas generation of the rechargeable lithium battery cell was measured in substantially the same method as above to calculate the gas increase rate (%) according to Equation 3, and the results are shown in Table 3.

[0180] Equation 3

[0181] Gas increase rate [%] = ((amount of gas generation after storing at a high temperature for 7 days - initial gas generation amount) / initial gas generation amount) x 100

[0182] Table 3

[0183] DC-IR increase rate [%] Gas increase rate [%] Example 1 15 39 Example 2 14 35 Example 3 18 43 Example 4 19 41 Comparative Example 1 (Reference) 58 79 Comparative Example 2 30 51 Comparative Example 3 32 53

[0184] Summary

[0185] Referring to Tables 2 and 3, the rechargeable lithium battery cells using each of the electrolytes of Examples 1 to 4 exhibited an improvement of 10% or more in the 200-cycle lifespan characteristics (capacity retention rate) after high-temperature storage compared to the electrolyte using Comparative Example 1 (reference), thus exhibiting a significantly reduced DC-IR increase rate and gas increase rate.

[0186] In one or more embodiments, referring to Examples 1 to 4, the type (or kind) and / or amount of the additive represented by Chemical Formula 1 can be adjusted to control its effect.

[0187] However, compared to the rechargeable lithium battery cell using the electrolyte of Comparative Example 1, the rechargeable lithium battery cells using the electrolytes of Comparative Examples 2 and 3, respectively, showed improved 200-cycle life characteristics (capacity retention rate) after high-temperature storage, as well as reduced DC-IR increase rate and gas increase rate, but these improvements were not as good as the improvements of the rechargeable lithium battery cells of Examples 1 to 4 compared to Comparative Example 1. Here, it was confirmed that the cycloalkyl group increased the polarity of the additive represented by Chemical Formula 1 and improved the reactivity between the isocyanate group and moisture compared to the alkyl group.

[0188] In one or more embodiments, it is confirmed that the electrolyte according to one or more embodiments represented by Examples 1 to 4 effectively removes moisture inside the rechargeable lithium battery cell to inhibit or reduce the reaction between the lithium salt and moisture, and inhibits or reduces the side reaction with the transition metal ions dissolved from the positive electrode active material, ultimately improving or enhancing the charge / discharge characteristics and / or high-temperature storage characteristics of the rechargeable lithium battery cell.

[0189] Although the subject matter of the present disclosure has been described in conjunction with what are presently considered to be practical embodiments, it should be understood that the embodiments of the present disclosure are not limited to the disclosed embodiments, but on the contrary, are intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents. Therefore, it will be understood that the above-described one or more embodiments are illustrative only and not restrictive in all respects.

Claims

1.An electrolyte for a rechargeable lithium battery, comprising: a non-aqueous organic solvent; a lithium salt; and an additive represented by Chemical Formula 1: Chemical Formula 1 R-L-N=C=O, wherein, in Chemical Formula 1, R is a substituted or unsubstituted C3 to C20 cycloalkyl; and L is a single bond or a substituted or unsubstituted C1 to C20 alkylene. 2.The electrolyte of claim 1, wherein: R is a substituted or unsubstituted C3 to C10 cycloalkyl. 3.The electrolyte of claim 1, wherein: R is represented by Chemical Formula 2-1 or Chemical Formula 2-2: Chemical Formula 2-1 Chemical Formula 2-2 wherein, in Chemical Formula 2-1 and Chemical Formula 2-2, 4.The electrolyte of claim 3, wherein: R 1 ~R 9 each independently is a hydrogen atom, a halogen atom or a C1-C20 alkyl group, and * indicates a connection site with Chemical Formula 1. the additive represented by Chemical Formula 1 is represented by Chemical Formula 1-1 or Chemical Formula 1-2: Chemical Formula 1-1 Chemical Formula 1-2 wherein, in Chemical Formula 1-1 and Chemical Formula 1-2, 5.The electrolyte of claim 4, wherein: R 1 ~R 9 each independently is a hydrogen atom, a halogen atom or a C1-C20 alkyl group. 6.The electrolyte of claim 1, wherein: R 1 ~R 9 are both hydrogen atoms. an amount of the additive represented by Chemical Formula 1 is included in a range of 0.01 wt% to 10 wt% based on a total amount of 100 wt% of the electrolyte. 7.The electrolyte of claim 6, wherein: an amount of the additive represented by Chemical Formula 1 is included in a range of 0.1 wt% to 5 wt% based on a total amount of 100 wt% of the electrolyte. 8.The electrolyte of claim 1, wherein: the non-aqueous organic solvent includes ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate. 9.The electrolyte of claim 1, wherein: the lithium salt includes LiPF6. 10.The electrolyte of claim 1, wherein: a molar concentration of the lithium salt in the electrolyte is in a range of 1.0 M to 2.0 M. 11.A rechargeable lithium battery, comprising: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and the electrolyte according to any one of claims 1 to 10. 12.The rechargeable lithium battery of claim 11, wherein: the positive electrode active material includes a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free lithium nickel manganese-based oxide, or a combination thereof. 13.The rechargeable lithium battery of claim 12, wherein: the positive electrode active material includes a lithium iron phosphate-based compound represented by Chemical Formula 13: Chemical Formula 13 wherein, 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, Li a3 Fe x3 M 4 y3 PO 4-b3 X b3 X is one or more selected from fluorine, phosphorus, and sulfur. 14.The rechargeable lithium battery of claim 11, wherein: M 4 is selected from one or more of aluminum, boron, barium, calcium, cerium, cobalt, chromium, copper, magnesium, manganese, molybdenum, nickel, selenium, silicon, tin, strontium, titanium, vanadium, tungsten, yttrium, zinc, and zirconium, and the negative electrode active material includes a Si-based negative electrode active material, a Sn-based negative electrode active material, a carbon-based negative electrode active material, or a combination thereof. 15.The rechargeable lithium battery of claim 14, wherein: the negative electrode active material includes a carbon-based negative electrode active material. ​ ​

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