Compounds for electrolytes, compounds for electrolyte additives, electrolyte substances, electrolyte additives, electrolytes for secondary batteries and secondary batteries

Abstract

The present invention relates to compounds for electrolytes, compounds for electrolyte additives, electrolyte substances, electrolyte additives, electrolytes for secondary batteries, and secondary batteries, and provides an electrolyte for secondary batteries containing a novel compound or its isomer.

Description

[Technical Field]

[0001] The present invention relates to compounds for electrolytes, compounds for electrolyte additives, electrolyte substances, electrolyte additives, electrolytes for secondary batteries, and secondary batteries. [Background technology]

[0002] Lithium-ion batteries are used as power sources for portable electronic devices such as video cameras, mobile phones, and laptop computers. Rechargeable lithium-ion batteries have more than three times the energy density per unit weight compared to conventional lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries, and can be rapidly charged. Because lithium secondary batteries operate at high drive voltages, highly reactive aqueous electrolytes cannot be used. Generally, organic electrolytes are used as electrolytes for lithium secondary batteries. Organic electrolytes are manufactured by dissolving lithium salts in an organic solvent. Organic solvents are preferably stable at high voltages, have high ionic conductivity and dielectric constant, and have low viscosity. On the other hand, the voltage, lifespan, capacity, and stability of a battery can vary significantly depending on the materials used for the negative electrode, positive electrode, and electrolyte. Therefore, there is a need for lithium-ion battery electrolytes that can provide lithium-ion batteries with improved lifespan characteristics and high-temperature stability. [Overview of the project] [Problems that the invention aims to solve]

[0003] The object of the present invention is to provide an electrolyte for secondary batteries containing a novel compound or its isomer.

[0004] Another object of the present invention is to provide a secondary battery containing the electrolyte for secondary batteries. [Means for solving the problem]

[0005] To achieve the above objective, one embodiment of the present invention provides an electrolyte for a secondary battery containing an additive.

[0006] The electrolyte for the secondary battery is (A) a first additive represented by the following Chemical Formula 1, and (B) one or more second additives selected from the group consisting of lithium difluorophosphate (LiPO2F 2) , lithium difluoro(oxalato)borate (LiFOB), lithium bis(oxalato)borate (LiB(C2O4)2, LiBOB), vinylene carbonate (VC), and vinyl ethylene carbonate (VEC). Electrolyte for secondary battery: [Chemical Formula 1] [Chemistry] In Chemical Formula 1, the carbons in the ring are linked by single bonds or double bonds, X is oxygen or sulfur, Y is oxygen or sulfur, Z 1 is each independently hydrogen, substituted or unsubstituted C 1-10 alkyl, substituted or unsubstituted C 1-10 alkenyl, substituted or unsubstituted C 1-10 alkynyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 1-12 heteroalkyl, substituted or unsubstituted C 1-6 heterocycloalkyl, substituted or unsubstituted C 1-10 amine, substituted or unsubstituted C 1-10 acyl, and is selected from the group consisting of Z 2 and Z 3 are each independently hydrogen, substituted or unsubstituted C 1-10 alkyl, substituted or unsubstituted C 1-10 alkenyl, substituted or unsubstituted C 1-10 alkynyl.

[0007] In one embodiment of the present invention, the substituted alkyl, alkenyl, amine, acyl, alkynyl, cycloalkyl, silyl, alkoxy, heteroalkyl, and heterocycloalkyl groups may each be independently substituted with one or more substituents selected from the group consisting of alkoxy groups, alkynyloxy groups, heteroaryl groups, alkenyl groups, heterocycloalkyl groups, carbonyl groups, halogen groups, hydroxyl groups, alkenyloxy groups, carboxyl groups, carbonate groups, alkyl groups, alkynyl groups, amine groups, cycloalkyl groups, silyl groups, sulfonate groups, phosphate groups, thiophosphate groups, nitro groups, cyano groups, heteroalkyl groups, cycloalkyl groups, aryl groups, and ether groups.

[0008] In one embodiment of the present invention, the electrolyte may further contain one or more additives selected from the group consisting of unsaturated cyclic carbonates, cyclic sulfetralactones, and nitrile compounds.

[0009] In one embodiment of the present invention, the unsaturated cyclic carbonate may be selected from the group consisting of phenyl carbonate, vinyl carbonate, and allyl carbonate.

[0010] In one embodiment of the present invention, the electrolyte may further contain an organic solvent.

[0011] In another aspect of the present invention, a lithium-ion battery is provided that includes the non-aqueous electrolyte for secondary batteries.

[0012] In one embodiment of the present invention, a secondary battery can be provided which includes an electrode assembly comprising a positive electrode, a negative electrode, and a separator separating the positive electrode and the negative electrode, a case for housing the electrode assembly, and an electrolyte solution housed in the case and immersing the electrode assembly. [Effects of the Invention]

[0013] A secondary battery containing the electrolyte additive and electrolyte for secondary batteries according to the present invention can improve the lifespan performance at room temperature. [Brief explanation of the drawing]

[0014] [Figure 1] A cross-sectional view of a secondary battery including an electrolyte and an electrolyte additive according to one embodiment of the present invention is shown. [Figure 2] This figure shows the results of an analysis of the lifespan performance at room temperature for a secondary battery according to one embodiment of the present invention. [Modes for carrying out the invention]

[0015] One embodiment of the present invention is shown in the accompanying drawings. However, the spirit of the present invention can be embodied in many other forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided so as to make the present disclosure thorough and complete and will fully convey the scope of the spirit of the invention to a person of ordinary skill in the art. The same reference numerals in the drawings refer to the same components.

[0016] The terms used herein are for the purpose of describing specific embodiments only and do not limit the ideas of the invention. The singular form used herein is intended to include multiple forms, including “at least one,” unless explicitly indicated otherwise in the text. “At least one” should not be construed as limiting to the singular. As used herein, the term “and / or” includes all any combination of one or more of the listed items. The terms “include” and / or “contain” as used in the detailed description identify the presence of the described features, regions, integers, steps, operations, components, and / or ingredients, and do not exclude the presence or addition of one or more other features, regions, integers, steps, operations, components, ingredients, and / or groups thereof.

[0017] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as they would be generally understood by a person of ordinary skill in the art to which this disclosure belongs. Furthermore, it will be understood that terms defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art and this disclosure, and not as idealized or overly formal.

[0018] While specific embodiments are described, alternatives, modifications, variations, improvements, and substantial equivalents not currently anticipated or foreseeable may occur to the applicant or those skilled in the art. Therefore, the attached claims, which may be filed and amended, are intended to include all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0019] In this invention, the term "isomer" refers to a compound or salt thereof of the present invention that has the same chemical or molecular formula but is structurally or sterically different. Such isomers include structural isomers such as tautomers, stereoisomers such as R or S isomers with asymmetric carbon centers, geometric isomers (trans, cis), and optical isomers. All of these isomers and mixtures thereof are also within the scope of this invention.

[0020] In this invention, the term "alkyl" may refer to a linear or branched chain unless otherwise specified, and the number of carbon atoms is not particularly limited but may range from 1 to 7. Specific examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, and n-heptyl.

[0021] In this specification, the term "alkenyl" may refer to an alkyl group containing one or more double bonds, whether linear or branched, unless otherwise specified. The number of carbon atoms is not particularly limited, but may range from 2 to 6. Specific examples include, but are not limited to, vinyl, 1-profenyl, isoprofenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1-butenyl, and 1,3-butadienyl.

[0022] In this specification, the term "alkynyl" may refer to an alkyl group containing one or more triple bonds, whether linear or branched, unless otherwise specified. The number of carbon atoms is not particularly limited, but may range from 2 to 6. Specific examples include, but are not limited to, ethynyl, propanyl, butynyl, and pentynyl groups.

[0023] The term "amine" as used herein may be selected from the group consisting of -NH2, alkylamine group, N-alkylarylamine group, arylamine group, N-arylheteroarylamine group, N-alkylheteroarylamine group, and heteroarylamine group, and the number of carbon atoms is not particularly limited, but may be 1 to 30. More specific examples of amine groups include, but are not limited to, methylamine group, dimethylamine group, ethylamine group, diethylamine group, phenylamine group, naphthylamine group, biphenylamine group, anthracenylamine group, 9-methyl-anthracenylamine group, diphenylamine group, ditolylamine group, N-phenyltolylamine group, triphenylamine group, N-phenylbiphenylamine group, N-phenylnaphthylamine group, N-biphenylnaphthylamine group; N-naphthylfluorenylamine group, N-phenylphenantrenylamine group, N-biphenylphenantrenylamine group, N-phenylfluorenylamine group, N-phenylterphenylamine group, N-phenantrenylfluorenylamine group, and N-biphenylfluorenylamine group.

[0024] In this specification, the term "heteroalkyl" refers to an alkyl group containing one or more heteroatoms from O, N, Si, B, Se, P, and S, and the number of carbon atoms is not particularly limited, but can range from 1 to 6. Examples of heteroalkyl groups include, but are not limited to, -CH2-CH2-O-CH3, -CH2-CH2-NH-CH3, -CH2-CH2-N(CH3)-CH3, and -CH2-S-CH2-CH3.

[0025] In this specification, the term "cycloalkyl" refers to a non-aromatic carbon ring, and the number of carbon atoms is not particularly limited, but may range from 3 to 12. Examples of cycloalkyls include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl.

[0026] In this specification, the term "heterocycloalkyl" refers to a cycloalkyl compound containing one or more heterogeneous elements from O, N, Si, B, Se, P, and S, and is not particularly limited in terms of the number of carbon atoms, but can range from 3 to 12. Examples of heterocycloalkyl compounds include, but are not limited to, epoxy, tetrahydrofuranyl, tetrahydropyranyl, tetrahydrothiophenyl, and tetrahydropyrrolyl.

[0027] The term "aryl" as used herein is not particularly limited, but may have 6 to 20 or 6 to 12 carbon atoms. Examples of monocyclic aryl groups include, but are not limited to, phenyl, biphenyl, and terphenyl groups. Examples of polycyclic aryl groups include, but are not limited to, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, ferrylenyl, clysenyl, and fluorenyl groups.

[0028] In this specification, the term "heteroaryl" refers to an aryl compound containing one or more of the following heteroatoms: O, N, Si, B, Se, P, and S. The number of carbon atoms is not particularly limited, but can range from 5 to 20. Examples of heteroaryl groups include, but are not limited to, xanthene, thioxanthen, thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine group, acridyl group, pyridazine group, pyrazinyl group, quinoline group, quinazoline group, quinoxalinyl group, phthalazinyl group, pyridopyrimidinyl group, pyridopyradinyl group, pyrazinopyradinyl group, isoquinoline group, indole group, carbazole group, benzoxazole group, benzimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuran group, phenanthroline group, isoxazolyl group, thiadiazolyl group, phenothiazine group, and dibenzofuran group.

[0029] In this specification, the term "alkoxy" refers to an alkyl group bonded to oxygen, and oxygen can be bonded to the aforementioned alkyl group. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, butoxy, and pentoxy groups.

[0030] In this specification, the term "acyl" refers to the residue remaining after removing the OH group from the carboxyl group (-COOH) of a carboxylic acid, and the number of carbon atoms is not particularly limited, but may range from 1 to 6. Examples of acyls include, but are not limited to, acetyl, propionyl, malonyl, and benzoyl groups.

[0031] The term "silyl" as used herein may be represented as -SiR3, and examples of silyls may be selected from, but are not limited to, alkylsilyl groups, arylsilyl groups, alkylarylsilyl groups, and heteroarylsilyl groups. More specific examples include, but are not limited to, trimethylsilyl groups, triethylsilyl groups, t-butyldimethylsilyl groups, vinyldimethylsilyl groups, propyldimethylsilyl groups, triphenylsilyl groups, diphenylsilyl groups, and phenylsilyl groups.

[0032] In this specification, the terms "substituted or unsubstituted" may mean substituted or unsubstituted with one or more groups selected from the group consisting of alkoxy groups, alkynyloxy groups, heteroaryl groups, alkenyl groups, heterocycloalkyl groups, carbonyl groups, halogen groups, hydroxyl groups, alkenyloxy groups, carboxyl groups, carbonate groups, alkyl groups, alkynyl groups, amine groups, cycloalkyl groups, silyl groups, sulfonate groups, phosphate groups, thiophosphate groups, nitro groups, cyano groups, heteroalkyl groups, cycloalkyl groups, aryl groups, and ether groups.

[0033] Furthermore, throughout this specification, the same symbol may have the same meaning unless otherwise specified.

[0034] The present invention relates to compounds for electrolytes, compounds for electrolyte additives, electrolyte substances, electrolyte additives, electrolytes for secondary batteries, and secondary batteries.

[0035] The electrolyte for secondary batteries of the present invention may contain the following additives.

[0036] (A) A first additive represented by the following chemical formula 1, and (B) May contain one or more second additives selected from the group consisting of lithium difluorophosphate (LiPO2F2), lithium difluoro(oxalate) borate (LiFOB), lithium bis(oxalate) borate (LiB(C2O4)2, LiBOB), vinylene carbonate (VC), and vinyl ethylene carbonate (VEC).

[0037] The aforementioned compound can be represented by the following chemical formula 1. [Chemical Formula 1] [ka] In the above chemical formula 1, the carbon atoms in the ring are linked by single or double bonds, The aforementioned X is oxygen or sulfur, The aforementioned Y is oxygen or sulfur, Said Z 1 Each of these is independently hydrogen, substituted or unsubstituted C 1-10 Alkyl, substituted, or unsubstituted C 1-10 Alkenyl, substituted, or unsubstituted C 1-10 Alkynyl, substituted, or unsubstituted C 3-10 Cycloalkyl, substituted, or unsubstituted C 1-12 Heteroalkyl, substituted, or unsubstituted C 1-6 Heterocycloalkyl, substituted or unsubstituted C 1-10 Amine, substituted or unsubstituted C 1-10 Selected from the group consisting of acyls, Said Z 2 and Z 3 Each of these is independently hydrogen, substituted or unsubstituted C 1-10 Alkyl, substituted, or unsubstituted C 1-10 Alkenyl, substituted, or unsubstituted C 1-10 It is alkinyl.

[0038] In one embodiment of the present invention, the compound represented by chemical formula 1 is a compound derived from a heterocyclic compound and can be added to an electrolyte as an additive for lithium secondary batteries. The additive of the present invention can form a stable SEI (Solid Electrolyte Interphase) film on the negative electrode surface while minimizing the increase in resistance of the lithium secondary battery. Therefore, it is possible to suppress the decrease in the passivation capacity of SEI at high temperatures, prevent deterioration of the negative electrode, and form a film that facilitates lithium movement, thereby improving the lifespan at room temperature.

[0039] The compound represented by chemical formula 1 of the present invention is, specifically, the Z1 These are, independently, hydrogen, substituted or unsubstituted C 1-10 Alkyl, substituted, or unsubstituted C 1-10 Alkenyl, substituted, or unsubstituted C 1-10 Alkynyl, substituted, or unsubstituted C 1-10 Amine, substituted or unsubstituted C 1-10 The group consisting of acyls may be selected.

[0040] The compound represented by chemical formula 1 of the present invention is, more specifically, the Z 2 and Z 3 Each of these is independently hydrogen, substituted or unsubstituted C 1-10 The group consisting of alkyl groups may be selected.

[0041] The substituted alkyl, alkenyl, amine, acyl, alkynyl, cycloalkyl, silyl, alkoxy, heteroalkyl, and heterocycloalkyl groups of the present invention may each be independently substituted with one or more substituents selected from the group consisting of alkoxy groups, alkynyloxy groups, heteroaryl groups, alkenyl groups, heterocycloalkyl groups, carbonyl groups, halogen groups, hydroxyl groups, alkenyloxy groups, carboxyl groups, carbonate groups, alkyl groups, alkynyl groups, amine groups, cycloalkyl groups, silyl groups, sulfonate groups, phosphate groups, thiophosphate groups, nitro groups, cyano groups, heteroalkyl groups, cycloalkyl groups, aryl groups, and ether groups. For example, the substituted alkoxy group may be substituted with an alkenyl group, an alkynyl group, an amine group, a cycloalkyl group, a carbonyl group, or a silyl group; the substituted heterocycloalkyl group may be substituted with a carbonyl group; the substituted carboxyl group may be substituted with a heteroaryl group, an alkenyl group, a heterocycloalkyl group, a carbonyl group substituted with a heterocycloalkyl group, or a halogen group; and the substituted carbonate group may be substituted with an alkyl group or an alkynyl group. Furthermore, the substituted sulfonate group may be substituted with an alkyl group, an alkenyl group, or a halogen-substituted alkyl group; and the substituted sulfonate group and the thiophosphate group may each be independently substituted with an alkyl group.

[0042] The electrolyte for the secondary battery of the present invention contains the compound represented by the chemical formula 1 as a first additive, and may further contain a second additive. For example, it may contain one or more second additives selected from the group consisting of lithium difluorophosphate (LiPO2F2), lithium difluoro(oxalate) borate (LiFOB), lithium bis(oxalate) borate (LiB(C2O4)2, LiBOB), vinylene carbonate (VC), and vinylethylene carbonate (VEC).

[0043] In any embodiment of the present invention, the additive may further include, in addition to the first and second additives, one or more additives selected from the group consisting of unsaturated cyclic carbonates, cyclic sulfe lactones, and nitrile compounds.

[0044] The unsaturated cyclic carbonate of the present invention is a cyclic carbonate having carbon-carbon unsaturated bonds, such as carbon-carbon double bonds or carbon-carbon triple bonds, and is not particularly limited; any unsaturated cyclic carbonate can be used.

[0045] As the additional additive of the present invention, the unsaturated cyclic carbonate can be one or more selected from the group consisting of vinylene carbonate, phenyl carbonate, vinyl carbonate, and allyl carbonate. As the vinylene carbonates, one or more can be selected from methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, and 4,5-diallyl vinylene carbonate.

[0046] As an additional additive to the present invention, cyclic sultones can be added. In one embodiment, 1,3-propanesultone, 1-fluoro-1,3-propanesultone, 2-fluoro-1,3-propanesultone, 3-fluoro-1,3-propanesultone, 1,4-butanesultone, methylenemethanedisulfonate, and ethylenemethanedisulfonate are preferred in terms of improving storage properties, and at least one selected from the group consisting of 1,3-propanesultone, 1-fluoro-1,3-propanesultone, 2-fluoro-1,3-propanesultone, and 3-fluoro-1,3-propanesultone can be added.

[0047] As a specific embodiment of the present invention, the compound represented by chemical formula 1 may include at least one compound or isomer selected from the group represented by the following chemical formula:

[0048] [ka]

[0049] [ka]

[0050] [ka]

[0051] Furthermore, the compounds of the present invention may have a chiral carbon center and therefore may exist in the form of R or S isomers, racemic compounds, individual enantiomers or mixtures, individual diastereoisomers or mixtures, and all such stereoisomers and mixtures thereof may fall within the scope of the present invention.

[0052] The additive of the present invention may be present in an amount of about 0.1% by weight or more based on the total weight of the total electrolyte, but is not limited to this, and an appropriate amount can be used as needed within the above content range.

[0053] If the amount of the additive in the total electrolyte is too high, the excess gas may cause the battery to swell, which could reduce its lifespan.

[0054] From this perspective, the content of the additives is based on the total weight of the total electrolyte and is 0.01-10% by weight, 0.01-9% by weight, 0.01-8% by weight, 0.01-7% by weight, 0.01-6% by weight, 0.01-5% by weight, 0.01-4% by weight, 0.01-3% by weight, 0.01-2% by weight, 0.01-1% by weight, 0.1-10% by weight, 0.1-9% by weight, 0.1-8% by weight, 0.1-7% by weight, 0.1-6% by weight, 0.1-5% by weight, and 0.1% by weight. The concentration can be ~4% by weight, 0.1~3% by weight, 0.1~2% by weight, 0.1~1% by weight, 1~10% by weight, 1~9% by weight, 1~8% by weight, 1~7% by weight, 1~6% by weight, 1~5% by weight, 1~4% by weight, 1~3% by weight, 1~2% by weight, 5~10% by weight, 5~9% by weight, 5~8% by weight, 5~7% by weight, or 5~6% by weight, as long as it functions as an overcharge protection agent without degrading the lifespan characteristics.

[0055] On the other hand, in one embodiment, the electrolyte for the secondary battery may further contain a lithium salt and an organic solvent.

[0056] The concentration of the lithium salt in the electrolyte may be approximately 0.01 to 2.0 M, but is not necessarily limited to this range, and an appropriate concentration can be used as needed. Further improved battery characteristics can be obtained within the aforementioned concentration range.

[0057] The lithium salt used in the electrolyte is not particularly limited, and any lithium salt that can be used in the art is acceptable. For example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiC2F6NO4S2, LiB(C2O4)2, LiN(C x F 2x+1 SO2)(C y F 2y+1You may use one or more selected from the group consisting of SO2) (where x and y are one or more independent integers), LiCl, and LiI.

[0058] The organic solvent may include one or more selected from the group consisting of dialkyl carbonates, cyclic carbonates, linear or cyclic esters, linear or cyclic amides, aliphatic nitriles, linear or cyclic ethers, and derivatives thereof.

[0059] Specifically, the organic solvent may include, but is not limited to, one or more selected from the group consisting of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, diethyl carbonate (DEC), dipropyl carbonate, propylene carbonate (PC), ethylene carbonate (EC), fluoroethylene carbonate (FEC), butylene carbonate, ethyl propionate (EP), ethyl butyrate, acetonitrile (AN), succinone nitrile (SN), dimethyl sulfoxide, dimethylformamide, dimethylacetamide, γ-valerolactone, γ-butyrolactone, and tetrahydrofuran. Any organic solvent that can be used as an organic electrolyte in the art is acceptable.

[0060] Another embodiment of the present invention provides a secondary battery containing the electrolyte for the secondary battery. The secondary battery includes an electrode assembly comprising a positive electrode, a negative electrode, and a separator that separates the positive electrode and the negative electrode. A case for housing the electrode assembly, and The case may contain the electrolyte for the secondary battery, which is housed within the case and immersed in the electrode assembly.

[0061] The aforementioned secondary battery is not particularly limited in form and includes, but is not limited to, lithium-ion batteries, lithium-ion polymer batteries, lithium-sulfur batteries, lithium-air batteries, etc.

[0062] For example, if the secondary battery is a lithium-ion battery, it can be manufactured by the following method.

[0063] First, the positive electrode is prepared.

[0064] For example, a positive electrode active material composition is prepared by mixing a positive electrode active material, a conductive material, a binder, and a solvent. A positive electrode plate is manufactured by directly coating the positive electrode active material composition onto a metal current collector. Alternatively, the positive electrode active material composition can be cast onto a separate support, and then the film peeled off the support is laminated onto the metal current collector to manufacture a positive electrode plate. The positive electrode is not limited to the forms listed above, and may be in forms other than those listed above.

[0065] The positive electrode active material is a lithium-containing metal oxide, and any of those commonly used in the art can be used without limitation. For example, one or more composite oxides of lithium with metals selected from cobalt, manganese, nickel, and combinations thereof can be used, and a specific example is Li a A 1-b B b D2 (wherein the above formula, 0.90 ≤ a ≤ 1.8 and 0 ≤ b ≤ 0.5), Li a E 1-b B b O 2-C D C (In the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.05), LiE 2-b B b O 4-C D C (In the above formula, 0≦b≦0.5 and 0≦c≦0.05), Li a Ni 1-b-C Co b B C D α (In the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α ≤ 2), Li a Ni 1-b-C Co b B C O 2-α Fα (In the above formula, 0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05, 0 < α < 2), Li a Ni 1-b-C Co b B C O 2-α F2 (In the above formula, 0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05, 0 < α < 2), Li a Ni 1-b-C Mn b B C D α (In the above formula, 0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05, 0 < α ≦ 2), Li a Ni 1-b-C Mn b B C O 2-α F α (In the above formula, 0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05, 0 < α < 2), Li a Ni 1-b-C Mn b B c O 2-α F2 (In the above formula, 0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05, 0 < α <​​​​​​​​​​​​​​​​​​​​​​​​​​​O2 (In the above formula, 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1), Li a Mn2G b O4 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1 in the above formula), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li (3-F) J2(PO4)3(0≦f≦2), Li (3ーF) Compounds represented by either the chemical formula Fe2(PO4)3 (0≦f≦2) or LiFePO4 can be used.

[0066] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D is O, F, S, P, or a combination thereof; E is CO, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0067] For example, LiCoO2, LiMn x O 2x (x=1, 2), LiNi 1-x Mn x O 2x (0 <x<1)、LiNi 1-x-y Co x Mn y Examples include O2 (0 ≤ x ≤ 0.5, 0 ≤ y ≤ 0.5) and LiFePO4.

[0068] Of course, compounds having a coating layer on their surface can also be used, or the compound and a compound having a coating layer can be mixed and used. This coating layer may include coating element compounds of oxide, hydroxide, oxyhydroxy, oxycarbonate, or hydroxycarbonate of the coating element. The compounds constituting these coating layers may be amorphous or crystalline. As coating elements included in the coating layer, Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof can be used. Any coating method can be used for the coating layer formation step, as long as the compound is coated with these elements in a way that does not adversely affect the physical properties of the positive electrode active material (e.g., spray coating, immersion method, etc.). Since this is something that people engaged in this field will understand well, a detailed explanation will be omitted. The conductive material can be carbon black, graphite fine particles, etc., but is not limited to these; any conductive material that can be used in the relevant technical field can be used.

[0069] As the binder, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene and mixtures thereof, or styrene-butadiene rubber polymers can be used, but are not limited to these; any binder that can be used in the art can be used.

[0070] As the aforementioned solvent, N-methylpyrrolidone, acetone, water, etc., can be used, but the solvent is not limited to these, and any solvent that can be used in the art can be used.

[0071] The content of the positive electrode active material, conductive material, binder, and solvent is at levels typically used in lithium-ion batteries. Depending on the application and configuration of the lithium-ion battery, one or more of the conductive material, binder, and solvent may be omitted.

[0072] Next, the negative electrode is prepared.

[0073] For example, a negative electrode active material composition is prepared by mixing a negative electrode active material, a conductive material, a binder, and a solvent. The negative electrode plate is manufactured by directly coating and drying the negative electrode active material composition onto a metal current collector. Alternatively, the negative electrode active material composition can be cast onto a separate support, and then the film peeled off the support is laminated onto a metal current collector to manufacture the negative electrode plate.

[0074] The negative electrode active material can be any material that can be used as a negative electrode active material for lithium-ion batteries in the art. For example, it may include one or more selected from the group consisting of lithium metal, metals alloyable with lithium, transition metal oxides, non-transition metal oxides, and carbon-based materials.

[0075] For example, the metals alloyable with lithium may be Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y alloys (where Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, and not Si), Sn-Y alloys (where Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, and not Sn), etc. The element Y may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0076] For example, the transition metal oxide can be lithium titanate, vanadium oxide, lithium vanadium oxide, or the like.

[0077] For example, the non-transition metal oxide can be SnO2, SiO x (0 < x < 3), or the like.

[0078] The carbon-based material can be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as amorphous, plate-like, flaky, spherical or fibrous natural graphite or artificial graphite, and the amorphous carbon may be soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, calcined coke, or the like.

[0079] In the negative electrode active material composition, the same conductive material and binder as those in the positive electrode active material composition can be used.

[0080] The contents of the negative electrode active material, conductive material, binder and solvent are at levels normally used in lithium ion batteries. Depending on the use and configuration of the lithium ion battery, one or more of the conductive material, binder and solvent can be omitted.

[0081] Next, a separator for separating the positive electrode and the negative electrode is prepared.

[0082] Any separator commonly used in lithium-ion batteries can be used. A separator with low resistance to electrolyte ion movement while possessing excellent electrolyte moisture absorption capacity can be used. For example, it may be a nonwoven or woven fabric selected from glass fiber, polyester, Teflon®, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or a combination thereof. For example, a rollable separator such as polyethylene or polypropylene can be used in lithium-ion batteries, while a separator with excellent organic electrolyte impregnation capacity can be used in lithium-ion polymer batteries. For example, the separator can be manufactured according to the following method.

[0083] A separator composition is prepared by mixing a polymer resin, a filler, and a solvent. The separator composition can be directly coated onto the electrode and dried to form a separator. Alternatively, the separator composition may be cast onto a support and dried, and then the separator film peeled off the support may be laminated onto the electrode to form a separator.

[0084] The polymer resin used in the manufacture of the separator is not particularly limited, and all substances used as binders for electrode plates can be used. For example, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, or mixtures thereof can be used.

[0085] Next, prepare the electrolyte solution for the secondary battery as described above.

[0086] As shown in Figure 1, the secondary battery 1 includes a positive electrode 40, a negative electrode 60, and a separator 50. The positive electrode 40, negative electrode 60, and separator 50 are wound up or folded and housed in cases 10 and 80. Subsequently, electrolyte is injected into cases 10 and 80 to complete the secondary battery 1.

[0087] The aforementioned case can have various forms depending on the application and design standards of the secondary battery, and can be formed to have various sizes and shapes, such as rectangular, thin-film, or button-shaped.

[0088] For example, the secondary battery may be a button-type battery. Specifically, the secondary battery may be a lithium-ion battery.

[0089] An electrode assembly can be formed by placing a separator between the positive electrode and the negative electrode. After stacking the electrode assembly in a bicell structure, it is impregnated with an electrolyte, and the resulting product is placed in a pouch and sealed to complete a lithium-ion polymer battery.

[0090] Furthermore, multiple electrode assemblies can be stacked to form a battery pack, which can then be used in all devices requiring high capacity and high output. For example, it can be used in laptop computers, smartphones, electric vehicles, and the like. [Examples]

[0091] The present invention will be described in detail below using manufacturing examples, embodiments, and experimental examples. However, the manufacturing examples, embodiments, and experimental examples described later are merely illustrative of one aspect of the present invention, and the present invention is not limited thereto.

[0092] <Manufacturing Example 1> Manufacturing of Compound 1 [ka] <Compound 1> 2-oxazolidinone (8 g, 0.09 mol) and triethylamine (18.6 g, 0.18 mol) were dissolved in methylene chloride (80 ml) in a 250 mL three-neck reactor, and then cooled to 0°C. Propargyl chloroformate (12.5 g, 0.1 mol) was added dropwise, and the mixture was stirred for 2 hours.

[0093] Water (80 mL) was added to the reactor and stirred vigorously, then allowed to stand and separate the layers. The aqueous layer was extracted with methylene chloride (100 mL x 2). Anhydrous magnesium sulfate was added to the organic layer and stirred for 5 minutes, after which the solid was filtered. The filtrate was concentrated and purified by column chromatography. 13 g of compound 1 (yield: 84%) was obtained, and this 1 H-NMR and 13 Confirmed by 13C-NMR.

[0094] 1 H-NMR (400MHz, CDCl3)d4.86(d, 2H, J=0.006Hz), 4.42-4.38(m, 2H), 4.08-4.04(m, 2H), 2.55-2.54(m, 1H) 13 C-NMR400MHz, CDCl3)d151.7, 150.3, 76.7, 76.1, 61.8, 54.4, 43.4

[0095] <Manufacturing Example 2> Manufacturing of Compound 2 [ka] <Compound 2> 2-thiazolidinone (8 g, 0.08 mol) and triethylamine (15.7 g, 0.16 mol) were dissolved in methylene chloride (80 ml) in a 250 mL three-neck reactor, and then cooled to 0°C. Propargyl chloroformate (10.5 g, 0.09 mol) was added dropwise, and the mixture was stirred for 2 hours.

[0096] Water (80 mL) was added to the reactor and stirred vigorously, then allowed to stand and separate the layers. The aqueous layer was extracted with methylene chloride (100 mL x 2). Anhydrous magnesium sulfate was added to the organic layer and stirred for 5 minutes, after which the solid was filtered. The filtrate was concentrated and purified by column chromatography. 12 g of compound 2 (yield: 84%) was obtained, and this 1 H-NMR and 13 Confirmed by 13C-NMR.

[0097] 1H-NMR (400MHz, CDCl3)d4.84(d, 2H, J=0.006Hz), 4.18-4.14(m, 2H), 3.32-3.28(m, 2H), 2.54-2.53(m, 1H) 13 C-NMR400MHz, CDCl3)d170.2, 149.9, 76.8, 76.0, 54.3, 47.6, 25.2

[0098] <Manufacturing Example 3> Battery Manufacturing A slurry of 96% by weight of artificial graphite (S360-L2-H Tiangin BTR New energy technology Co.,Ltd.), 1% by weight of SuperP (TIMCAL), 1.5% by weight of styrene-butadiene rubber (SBR) binder (ZEON), and 1.5% by weight of carboxymethylcellulose (CMC, Sigma-Aldrich) was mixed, then added to distilled water and stirred for 60 minutes using a mechanical stirrer to produce a negative electrode active material slurry. The slurry was coated onto a 30 μm thick copper current collector to a thickness of approximately 60 μm using a doctor blade, dried in a hot air dryer at 100°C for 1 hour, then dried again under vacuum conditions for 8 hours, and rolled (roll pressed) to produce a negative electrode plate.

[0099] LiRing 0.6 Mn 0.2 Co 0.2 A cathode active material slurry was prepared by mixing 2% by weight of superP(TIMCAL) and 2% by weight of polyvinylidene fluoride (PVDF, Sigma-Aldrich) as O296 wt% conductive material, adding the mixture to N-methyl-2-pyrrolidone solvent, and stirring for 30 minutes using a mechanical stirrer. The slurry was then coated to a thickness of 60 μm onto a 20 μm thick aluminum current collector using a doctor blade, dried in a 100°C hot air dryer for 1 hour, dried again under vacuum conditions for 8 hours, and then rolled (roll pressed) to produce a cathode plate.

[0100] Lithium batteries were manufactured using 14 μm thick polypropylene as the separator and electrolytes containing the additives described later in the Comparative Examples and Examples 1-7, respectively.

[0101] <Comparative Example 1> 1M LiPF6 was dissolved in a 1:1:1 volume-ratio mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) with a lithium salt.

[0102] The electrolyte was prepared by adding propargyl 1H-imidazole-1-carboxylate, represented by the following chemical formula, at a concentration of 0.5% by weight relative to 100% by weight of the organic electrolyte. [ka]

[0103] <Comparative Example 2> 1M LiPF6 was dissolved in a 1:1:1 volume-ratio mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) with a lithium salt.

[0104] An electrolyte was prepared by adding vinylene carbonate, represented by the following chemical formula, to the manufactured electrolyte at a concentration of 1% by weight relative to 100% by weight of the organic electrolyte.

[0105] <Comparative Example 3> 1M LiPF6 was dissolved in a 1:1:1 volume-ratio mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) with a lithium salt.

[0106] The electrolyte was prepared by adding lithium difluorophosphate to the manufactured electrolyte at a concentration of 1% by weight relative to 100% by weight of the organic electrolyte.

[0107] <Comparative Example 4> In the aforementioned Comparative Example 1, the electrolyte was prepared in the same manner except that compound 1 was replaced with compound 1 instead of 1H-imidazole-1-carboxylate.

[0108] <Comparative Example 5> In the aforementioned Comparative Example 1, the electrolyte was prepared in the same manner except that compound 2 was used instead of 1H-imidazole-1-carboxylate.

[0109] <Example 1> In the aforementioned Comparative Example 1, the electrolyte was prepared in the same manner, except that 0.5% by weight of 1H-imidazole-1-carboxylate was replaced with 0.5% by weight of Compound 1 and 0.5% by weight of vinylene carbonate.

[0110] <Example 2> The electrolyte was prepared in the same manner as in Comparative Example 1, except that 0.5% by weight of compound 2 and 0.5% by weight of vinylene carbonate were replaced with 0.5% by weight of 1H-imidazole-1-carboxylate.

[0111] <Example 3> In the aforementioned Comparative Example 1, the electrolyte was prepared in the same manner, except that 0.5% by weight of 1H-imidazole-1-carboxylate was replaced with 0.5% by weight of Compound 1 and 1% by weight of vinylene carbonate.

[0112] <Example 4> In the aforementioned Comparative Example 1, the electrolyte was prepared in the same manner, except that 0.5% by weight of 1H-imidazole-1-carboxylate was replaced with 1% by weight of Compound 1 and 1% by weight of vinylene carbonate.

[0113] <Example 5> In the same manner as in Comparative Example 1, the electrolyte was prepared except that 0.5% by weight of compound 2 and 1% by weight of vinylene carbonate were replaced with 0.5% by weight of 1H-imidazole-1-carboxylate.

[0114] <Example 6> In the aforementioned Comparative Example 1, the electrolyte was prepared in the same manner, except that 0.5% by weight of 1H-imidazole-1-carboxylate was replaced with 1% by weight of compound 2 and 1% by weight of vinylene carbonate.

[0115] <Example 7> In the aforementioned Comparative Example 1, the electrolyte was prepared in the same manner, except that 0.5% by weight of 1H-imidazole-1-carboxylate was replaced with 1% by weight of Compound 2 and 1% by weight of lithium difluorophosphate.

[0116] <Experimental Example 1> Evaluation of lifespan performance at room temperature To evaluate the performance of the electrolyte containing the additive of the present invention, a life performance evaluation was performed at room temperature. For lithium secondary batteries, constant current charging was performed at 25°C under constant current / constant voltage (CC / CV) conditions to 4.2V at a rate of 1.0 C-rate. Then, while maintaining 4.2V in constant voltage mode, the battery was cut off at a rate of 0.05 C-rate, and then discharged to 2.7V at a rate of 1.0 C-rate. The above charge / discharge conditions constituted one cycle and were repeated 200 times. The evaluation results of the additives for the comparative example and Examples 1 to 4 are shown in Table 1 and Figure 2.

[0117] [Table 1]

[0118] As can be seen from Table 1 and Figure 2, Examples 1 to 6, in which vinylene carbonate additive was added to Comparative Examples 4 and 5, showed a further increase in volume retention. Furthermore, Example 7, in which lithium difluorophosphate additive was added to Comparative Example 5, also showed an increase in volume retention.

[0119] <Experimental Example 2> Evaluation of Resistance Improvement Performance The batteries manufactured according to the examples were charged to 4.2V at 1C and then discharged to SOC50. After that, the initial DC-IR was measured by discharging for 10 seconds at four different C-rates (0.5, 1, 2, and 3C). After charging to 4.2V at 1C, 200 charge-discharge cycles were performed at room temperature, and the DC-IR was measured in the same manner as the initial DC-IR measurement method. The percentage relative to the initial DC-IR was expressed as a percentage and is shown in Table 2.

[0120] [Table 2] As can be seen from Table 2 above, in the examples where the compounds produced by the present invention were combined with Comparative Examples 2 and 3, the initial discharge resistance was higher than that of the comparative examples, yet the discharge resistance after 200 charge cycles tended to be lower than that of the comparative examples. In other words, it was confirmed that the DC-IR increase rate was lower than that of the comparative examples.

[0121] This confirmed that when the compounds produced by the present invention are combined, a film is formed that facilitates lithium movement, resulting in a significantly lower DC-IR increase rate, due to the low resistance increase rate.

[0122] The foregoing description of the present invention is illustrative, and a person with ordinary skill in the art will understand that the invention can be easily modified into other specific forms without altering the technical idea or essential features of the invention. Therefore, the embodiments described above should be understood to be illustrative in all respects and not limiting. For example, each component described in a single form can be implemented in a distributed manner, and similarly, components described as distributed can be implemented in a combined manner.

[0123] The scope of the present invention is defined by the claims described below, and all modifications or altered forms derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention. [Explanation of symbols]

[0124] 1: Secondary battery 10: Top Case 20: Spring 30: Spacer 40: Positive electrode 50: Separator 60: Negative electrode 70: Gasket 80: Bottom Case

Claims

1. (A) A first additive represented by the following chemical formula 1, and (B) Lithium difluorophosphate (LiPO ２ F ２） Lithium difluoro(oxalate) borate (LiFOB), lithium bis(oxalate) borate (LiB(C) ２ O ４ ) ２ It comprises one or more second additives selected from the group consisting of LiBOB, vinylene carbonate (VC), and vinylethylene carbonate (VEC), Electrolyte for secondary batteries: [Chemical Formula 1] 【Chemistry 1】 In the above chemical formula 1, the carbon atoms in the ring are linked by single or double bonds, The aforementioned X is oxygen or sulfur, Y is oxygen or sulfur, Said Z １ is each independently hydrogen, substituted or unsubstituted C １－１０ alkyl, substituted or unsubstituted C １－１０ alkenyl, substituted or unsubstituted C １－１０ alkynyl, substituted or unsubstituted C ３－１０ cycloalkyl, substituted or unsubstituted C １－１２ heteroalkyl, substituted or unsubstituted C １－６ heterocycloalkyl, substituted or unsubstituted C １－１０ amine, substituted or unsubstituted C １－１０ acyl, and is selected from the group consisting of, Said Z ２ and Z ３ Each of these is independently hydrogen, substituted, or unsubstituted C. １－１０ Alkyl, substituted, or unsubstituted C １－１０ Alkenyl, substituted, or unsubstituted C １－１０ It is alkinyl.

2. Said Z １ These are, independently, hydrogen, substituted or unsubstituted C １－１０ Alkyl, substituted, or unsubstituted C １－１０ Alkenyl, substituted, or unsubstituted C １－１０ Alkynyl, substituted, or unsubstituted C １－１０ Amine, substituted or unsubstituted C １－１０ An electrolyte for a secondary battery according to claim 1, selected from the group consisting of acyls.

3. Said Z ２ and Z ３ These are, independently, hydrogen, substituted or unsubstituted C １－１０ An electrolyte for a secondary battery according to claim 1, selected from the group consisting of alkyl groups.

4. The electrolyte for a secondary battery according to claim 1, wherein each of the substituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroalkyl, heterocycloalkyl, amine, and acyl groups is independently substituted with one or more substituents selected from the group consisting of a carbonyl group, halogen group, hydroxyl group, cyano group, alkyl group, alkenyl group, alkynyl group, heteroalkyl group, alkoxy group, alkenyloxy group, alkynyloxy group, amine group, and nitro group.

5. The electrolyte for a secondary battery according to claim 1, further comprising one or more additives selected from the group consisting of unsaturated cyclic carbonates, cyclic sulfetralactones, and nitrile compounds.

6. The electrolyte for a secondary battery according to claim 5, wherein the unsaturated cyclic carbonate is phenyl carbonate or allyl carbonate.

7. The electrolyte for the secondary battery according to claim 1 comprises at least one compound selected from the group represented by the following chemical formula, or an isomer thereof: 【Chemistry 2-1】 【Chemistry 2-2】 [Chemistry 2-3]

8. The electrolyte for a secondary battery according to claim 1, further comprising an organic solvent.

9. The electrolyte for a secondary battery according to claim 1, wherein the secondary battery is a lithium-ion battery.

10. An electrode assembly including a positive electrode, a negative electrode, and a separator for separating the positive electrode and the negative electrode. A case for housing the electrode assembly, and A secondary battery comprising an electrolyte for a secondary battery according to claim 1, which is housed in the case and immersed in the electrode assembly.

Images