Lithium secondary battery

Abstract

The present invention provides a lithium secondary battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein the positive electrode comprises a positive electrode active material and a first additive, the non-aqueous electrolyte comprises a lithium salt, an organic solvent, and a second additive, the first additive comprising at least one compound selected from the group consisting of compounds represented by Chemical Formula 1-1 and Chemical Formula 1-2, and the second additive comprising a cyclic sulfur oxide-based compound. Chemical Formula 1-1 and Chemical Formula 1-2 are as described in the specification.

Description

[Technical Field]

[0001] The present invention relates to a lithium secondary battery. [Background technology]

[0002] In recent years, the application areas of lithium secondary batteries have rapidly expanded from power supply for electronic devices such as electrical, electronic, communication, and computer equipment to power storage and supply for large-area devices such as automobiles and power storage devices. Accordingly, there has been an increasing demand for high-capacity, high-power, and highly stable secondary batteries.

[0003] The lithium secondary battery typically comprises a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, an electrolyte serving as a medium for transferring lithium ions, and a separator. The negative electrode active material may be a carbon-based active material or a silicon-based active material. The positive electrode active material may be a lithium transition metal oxide such as lithium cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), or lithium nickel-cobalt-manganese composite oxide.

[0004] On the other hand, in recent years, high driving voltages have been required to achieve high energy densities of lithium secondary batteries. However, when driven at such high voltages, problems such as depletion of electrolyte due to oxidative decomposition reaction of the electrolyte, gas generation, and elution of transition metals from the positive electrode active material can lead to problems such as reduced battery life, storage performance, and durability. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to solve the above-mentioned problems and to provide a lithium secondary battery having high-temperature durability, long-term life performance, and high-voltage stability by forming a highly durable coating on the surface of the positive electrode. [Means for solving the problem]

[0006] [1] The present invention provides a lithium secondary battery comprising: a positive electrode; a negative electrode; a separator interposed between the positive electrode and the negative electrode; and a non-aqueous electrolyte, wherein the positive electrode comprises a positive electrode active material and a first additive; the non-aqueous electrolyte comprises a lithium salt, an organic solvent, and a second additive; the first additive comprises at least one compound selected from the group consisting of compounds represented by the following Chemical Formula 1-1 and Chemical Formula 1-2; and the second additive comprises a cyclic sulfur oxide-based compound:

[0007] [Chemical formula 1-1] [ka]

[0008] In the above chemical formula 1-1, Y 11 is nitrogen (N) or R Y11 is a carbon (C) substituted with Y 12 are oxygen (O), sulfur (S), and R Y121 Nitrogen (N) substituted with, or R Y122 and R Y123 is a carbon (C) substituted with Y 13 is nitrogen (N) or R Y13 is a carbon (C) substituted with Y 14 is nitrogen (N) or R Y14 is a carbon (C) substituted with Y 15 is nitrogen (N) or R Y15 and a carbon (C) substituted with Y 11 and Y 15 At least one of the groups is nitrogen (N), and Y 11 , Y 12 , Y 13 , Y 14 , and Y 15 At least one of R is carbon (C), Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15are each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a, Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 At least one of the groups is a substituent represented by the above chemical formula 1-a.

[0009] [Chemical formula 1-2] [ka]

[0010] In the above chemical formula 1-2, Y 21 is nitrogen (N) or R Y21 is a carbon (C) substituted with Y 22 is nitrogen (N) or R Y22 is a carbon (C) substituted with Y 23 is nitrogen (N) or R Y23 is a carbon (C) substituted with Y 24 is nitrogen (N) or R Y24 is a carbon (C) substituted with Y 25 is nitrogen (N) or R Y25 and a carbon (C) substituted with Y 21 , Y 22 , Y 23 , Y 24 , and Y 25 At least one of R is carbon (C), Y21 , R Y22 , R Y23 , R Y24 , and R Y25 are each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a, Y21 , R Y22 , R Y23 , R Y24 , and R Y25 At least one of the groups is a substituent represented by the above chemical formula 1-a.

[0011] [Chemical formula 1-a] [ka]

[0012] In the above chemical formula 1-a, L1 is selected from a direct bond, an ester, an ether, and an alkylene group having 1 to 5 carbon atoms; R1 is a direct bond or an alkylene group having 1 to 5 carbon atoms; and R2 is *-CH=CH2 or *-C≡CH, where * is a bonding site.

[0013] [2] The present invention provides the lithium secondary battery according to [1] above, wherein the compound represented by Chemical Formula 1-1 includes at least one compound selected from the group consisting of compounds represented by Chemical Formula 1-1-A, Chemical Formula 1-1-B, Chemical Formula 1-1-C, Chemical Formula 1-1-D, Chemical Formula 1-1-E, and Chemical Formula 1-1-F:

[0014] [Chemical formula 1-1-A] [ka]

[0015] [Chemical formula 1-1-B] [ka]

[0016] [Chemical formula 1-1-C] [ka]

[0017] [Chemical formula 1-1-D] [ka]

[0018] [Chemical formula 1-1-E] [ka]

[0019] [Chemical formula 1-1-F] [ka]

[0020] In the chemical formulas 1-1-A, 1-1-B, 1-1-C, 1-1-D, 1-1-E, and 1-1-F, R Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 is as defined in Chemical Formula 1-1.

[0021] [3] The present invention provides the lithium secondary battery according to any one of [1] and [2] above, wherein the compound represented by Chemical Formula 1-2 includes at least one selected from the group consisting of compounds represented by Chemical Formula 1-2-A, Chemical Formula 1-2-B, Chemical Formula 1-2-C, Chemical Formula 1-2-D, and Chemical Formula 1-2-E:

[0022] [Chemical formula 1-2-A] [ka]

[0023] [Chemical formula 1-2-B] [ka]

[0024] [Chemical formula 1-2-C] [ka]

[0025] [Chemical formula 1-2-D] [ka]

[0026] [Chemical formula 1-2-E] [ka]

[0027] In the chemical formulas 1-2-A, 1-2-B, 1-2-C, 1-2-D, and 1-2-E, R Y21 , R Y22 , R Y23 , R Y24 , and R Y25 is as defined in Chemical Formula 1-2.

[0028] [4] The present invention provides the lithium secondary battery according to any one of [1] to [3] above, wherein the first additive comprises a compound represented by Chemical Formula 1-1.

[0029] [5] The present invention provides the lithium secondary battery according to any one of [1] to [4] above, wherein the compound represented by Chemical Formula 1-1 includes at least one selected from the group consisting of compounds represented by the following Chemical Formulas 1-1-A1 to 1-1-A4:

[0030] [Chemical formula 1-1-A1] [ka]

[0031] [Chemical formula 1-1-A2] [ka]

[0032] [Chemical formula 1-1-A3] [ka]

[0033] [Chemical formula 1-1-A4] [ka]

[0034] [6] The present invention provides the lithium secondary battery according to any one of [1] to [5], wherein the first additive is contained in the positive electrode in an amount of 0.004 to 8 parts by weight per 100 parts by weight of the positive electrode active material.

[0035] [7] The present invention provides the lithium secondary battery according to any one of [1] to [6], wherein the first additive is contained in the positive electrode in an amount of 0.04 parts by weight to 4 parts by weight per 100 parts by weight of the positive electrode active material.

[0036] [8] The present invention provides the lithium secondary battery according to any one of [1] to [7] above, wherein the cyclic sulfur oxide compound comprises at least one compound selected from the group consisting of compounds represented by the following chemical formula 2-a, chemical formula 2-b, chemical formula 2-c, chemical formula 2-d, chemical formula 2-e, chemical formula 2-f, and chemical formula 2-g:

[0037] [Chemical formula 2-a] [ka]

[0038] In the above chemical formula 2-a, X 11 and X 12 are, independently of each other, *-O-* or *-C(R X11 )(R X12 )-* and X 11 and X 12 At the same time, *-C(R X11 )(R X12 )-*, R 11 , R 14 , R X11 , and R X12 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; R 12 and R 13 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 10 to 10 alkynyl groups, halogen groups, or substituents represented by the following chemical formula 3, or R 12 and R 13 are each formed by a condensed ring to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, a cycloalkynyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, with the proviso that R 12 and R 13 When R forms an aryl group having 6 to 20 carbon atoms, 11 and R 14 does not exist, i is an integer of 1 or 2, * is the binding site, [Chemical formula 2-b] [ka] In the above chemical formula 2-b, R 21 , R 22 , R 23 , and R 24 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; [Chemical formula 2-c] [ka] In the above chemical formula 2-c, R 31 , R 32 , R 33 , and R 34 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; [Chemical formula 2-d] [ka] In the above chemical formula 2-d, R 41 , R 42 , R 43 , and R 46 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; R 44 and R 45 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 alkynyl groups, or halogen, or R 44 and R 45 are each formed by a condensed ring to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, a cycloalkynyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, with the proviso that R 44 and R 45 When R forms an aryl group having 6 to 20 carbon atoms, 43 and R 46 does not exist, [Chemical formula 2-e] [ka] In the above chemical formula 2-e, X 51 and X 52 are, independently of each other, *-O-* or *-C(R X51 )(R X52 )-* and X 51 and X 52 At the same time, *-C(R X51 )(R X52 )-*, R 51 , R 52 , R 53 , R 54 , R 55 , R 56 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; j is an integer of 1 or 2, [Chemical formula 2-f] [ka] In the above chemical formula 2-f, X 71 and X 72 are, independently of each other, *-O-* or *-C(R X71 )(R X72 )-* and X 71 and X 72 At the same time, *-C(R X71 )(R X72 )-*, X 73 and X 74 are, independently of each other, *-O-* or *-C(R X73 )(R X74 )-* and X 73 and X 74 At the same time, *-C(R X73 )(R X74 )-*, R X71 , R X72 , R X73 , R X74 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; m and n are, independently of each other, integers of 1 or 2; * is the binding site, [Chemical formula 2-g] [ka] In the above chemical formula 2-g, R 81 , R 82 , R 83 , and R 84 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number2 an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; [Chemical formula 3] [ka] In the above chemical formula 3, L 61 and L 62 are each independently a direct bond or an alkylene group having 1 to 5 carbon atoms, A is a substituent represented by the following chemical formula 4: X 61 and X 62 are, independently of each other, *-O-* or *-C(R X61 )(R X62 )-* and X 61 and X 62 At the same time, *-C(R X61 )(R X62 )-*, R 63 , R X61 , and R X62 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; R 61 and R 62 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 alkynyl group having 10 to 10 carbon atoms, or halogen group, or R 62 and R 63 are each formed by a condensed ring to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, or a cycloalkynyl group having 5 to 20 carbon atoms, k is an integer of 1 or 2, * is the binding site, [Chemical formula 4] [ka] In the above Chemical Formula 4, l is an integer of 1 or 2, and * is a binding site.

[0039] [9] The present invention provides the lithium secondary battery according to any one of [1] to [8] above, wherein the cyclic sulfur oxide compound comprises at least one compound selected from the group consisting of compounds represented by the following Chemical Formulas 2-a-1 to 2-a-25, 2-b-1, 2-c-1, 2-d-1, 2-e-1, 2-e-2, 2-f-1, and 2-g-1:

[0040] [Chemical formula 2-a-1] [ka]

[0041] [Chemical formula 2-a-2] [ka]

[0042] [Chemical formula 2-a-3] [ka]

[0043] [Chemical formula 2-a-4] [ka]

[0044] [Chemical formula 2-a-5] [ka]

[0045] [Chemical formula 2-a-6] [ka]

[0046] [Chemical formula 2-a-7] [ka]

[0047] [Chemical formula 2-a-8]

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[0048] [Chemical formula 2-a-9]

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[0049] [Chemical formula 2-a-10]

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[0050] [Chemical formula 2-a-11]

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[0051] [Chemical formula 2-a-12]

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[0052] [Chemical formula 2-a-13]

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[0053] [Chemical formula 2-a-14]

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[0054] [Chemical formula 2-a-15]

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[0055] [Chemical formula 2-a-16]

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[0056] [Chemical formula 2-a-17]

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[0057] [Chemical formula 2-a-18]

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[0058] [Chemical formula 2-a-20]

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[0059] [Chemical formula 2-a-21]

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[0060] [Chemical formula 2-a-22]

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[0061] [Chemical formula 2-a-23]

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[0062] [Chemical formula 2-a-24]

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[0063] [Chemical formula 2-a-25]

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[0064] [Chemical formula 2-b-1] [ka]

[0065] [Chemical formula 2-c-1] [ka]

[0066] [Chemical formula 2-d-1] [ka]

[0067] [Chemical formula 2-e-1] [ka]

[0068] [Chemical formula 2-e-2] [ka]

[0069] [Chemical formula 2-f-1] [ka]

[0070] [Chemical formula 2-g-1] [ka]

[0071]

[10] The present invention provides the lithium secondary battery according to any one of [1] to [9] above, wherein the second additive is contained in the non-aqueous electrolyte in an amount of 0.01% by weight to 10% by weight.

[0072]

[11] The present invention provides the lithium secondary battery according to any one of [1] to

[10] above, wherein the positive electrode active material contains a lithium transition metal oxide represented by the following chemical formula A:

[0073] [Chemical formula A] Li 1+x [Ni a Co b Mn c M 1 d ]O 2+w

[0074] In the chemical formula A, 0≦x≦0.5, a+b+c+d=1, 0.5≦a≦0.7, 0≦b≦0.15, c=1−abd, 0≦d≦0.1, 0≦b / a≦0.2, 1≦a / c≦3, and 0≦w≦1; M 1 is one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo.

[0075]

[12] The present invention provides the lithium secondary battery according to any one of [1] to

[11] above, wherein the negative electrode comprises a negative electrode active material, and the negative electrode active material comprises at least one selected from the group consisting of a carbon-based active material and a silicon-based active material. [Effects of the Invention]

[0076] The lithium secondary battery of the present invention is characterized by including a nitrogen-containing heteroaromatic compound of a specific chemical formula (Chemical Formula 1-1 and / or Chemical Formula 1-2) in the positive electrode as a first additive and a cyclic sulfur oxide-based compound in the non-aqueous electrolyte as a second additive. According to the present invention, the inclusion of the first additive in the positive electrode preferentially forms a coating that improves oxidation resistance. The second additive, which can be decomposed by chemical reaction with the first additive to form an additional coating, suppresses oxygen desorption from the positive electrode, ensuring the safety of the positive electrode-non-aqueous electrolyte interface, thereby achieving a lithium secondary battery with excellent life performance, high-temperature storage performance, and reduced resistance. The lithium secondary battery of the present invention exhibits particularly favorable effects when operated at high voltages, where problems such as electrolyte depletion, gas generation, and oxygen desorption from the positive electrode active material become more severe. DETAILED DESCRIPTION OF THE INVENTION

[0077] The terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, based on the principle that inventors can appropriately define the concepts of terms in order to best explain their inventions.

[0078] As used herein, the terms "comprises," "comprises," or "having" are intended to specify the presence of embodied features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the presence or possible addition of one or more other features, numbers, steps, components, or combinations thereof.

[0079] On the other hand, before describing the present invention, unless otherwise specified in the present invention, "*" means a linked portion (bonding site) between the ends of the same or different atoms or chemical formulae.

[0080] Furthermore, in the description of "number of carbon atoms a to b" herein, "a" and "b" refer to the number of carbon atoms contained in a specific functional group. That is, the functional group may contain "a" to "b" carbon atoms. For example, "an alkyl group having 1 to 5 carbon atoms" refers to an alkyl group containing 1 to 5 carbon atoms, i.e., CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, (CH3)2CHCH2-, CH3CH2CH2CH2CH2-, (CH3)2CHCH2CH2-, CH3)2CHCH2CH2-, (CH3)2CHCH2CH2-, etc.

[0081] In addition, in this specification, any alkyl group, alkenyl group, alkynyl group, alkoxy group, aryl group, or heteroaryl group may be substituted or unsubstituted. Unless otherwise defined, the term "substituted" means that at least one hydrogen atom bonded to a carbon atom is substituted with an element other than hydrogen, and includes, for example, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, a cycloalkynyl group having 3 to 12 carbon atoms, a heterocycloalkyl group having 3 to 12 carbon atoms, a heterocycloalkenyl group having 3 to 12 carbon atoms, a heterocycloalkynyl group having 2 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, a halogen atom, a fluoroalkyl group having 1 to 20 carbon atoms, a nitro group, an aryl group having 6 to 20 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, or a haloaryl group having 6 to 20 carbon atoms.

[0082] The present invention will be described in detail below.

[0083] Lithium secondary battery The present invention relates to a lithium secondary battery.

[0084] The lithium secondary battery according to the present invention includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein the positive electrode includes a positive electrode active material and a first additive, the non-aqueous electrolyte includes a lithium salt, an organic solvent, and a second additive, the first additive includes at least one selected from the group consisting of compounds represented by the following Chemical Formula 1-1 and Chemical Formula 1-2, and the second additive includes a cyclic sulfur oxide-based compound.

[0085] [Chemical formula 1-1] [ka]

[0086] In the above chemical formula 1-1, Y 11 is nitrogen (N) or R Y11 is a carbon (C) substituted with Y 12 are oxygen (O), sulfur (S), and R Y121 Nitrogen (N) substituted with, or R Y122 and R Y123 is a carbon (C) substituted with Y 13 is nitrogen (N) or R Y13 is a carbon (C) substituted with Y 14 is nitrogen (N) or R Y14 is a carbon (C) substituted with Y 15 is nitrogen (N) or R Y15 and a carbon (C) substituted with Y 11 and Y 15 At least one of the groups is nitrogen (N), and Y 11 , Y 12 , Y 13 , Y 14 , and Y 15 At least one of R is carbon (C), Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 are each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a,Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 At least one of the groups is a substituent represented by the above chemical formula 1-a.

[0087] [Chemical formula 1-2] [ka]

[0088] In the above chemical formula 1-2, Y 21 is nitrogen (N) or R Y21 is a carbon (C) substituted with Y 22 is nitrogen (N) or R Y22 is a carbon (C) substituted with Y 23 is nitrogen (N) or R Y23 is a carbon (C) substituted with Y 24 is nitrogen (N) or R Y24 is a carbon (C) substituted with Y 25 is nitrogen (N) or R Y25 and a carbon (C) substituted with Y 21 , Y 22 , Y 23 , Y 24 , and Y 25 At least one of R is carbon (C), Y21 , R Y22 , R Y23 , R Y24 , and R Y25 are each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a, Y21 , R Y22 , R Y23 , R Y24 , and R Y25 At least one of the groups is a substituent represented by the above chemical formula 1-a.

[0089] [Chemical formula 1-a] [ka]

[0090] In the above chemical formula 1-a, L1 is selected from a direct bond, an ester, an ether, and an alkylene group having 1 to 5 carbon atoms; R1 is a direct bond or an alkylene group having 1 to 5 carbon atoms; and R2 is *-CH=CH2 or *-C≡CH, where * is a bonding site.

[0091] The lithium secondary battery of the present invention is characterized by including a nitrogen-containing heteroaromatic compound of a specific chemical formula (Chemical Formula 1-1 and / or Chemical Formula 1-2) in the positive electrode as a first additive and a cyclic sulfur oxide-based compound in the non-aqueous electrolyte as a second additive. According to the present invention, the inclusion of the first additive in the positive electrode preferentially forms a coating that improves oxidation resistance. The second additive, which can be decomposed by chemical reaction with the first additive to form an additional coating, suppresses oxygen desorption from the positive electrode, ensuring the safety of the positive electrode-non-aqueous electrolyte interface, thereby achieving a lithium secondary battery with excellent life performance, high-temperature storage performance, and reduced resistance. The lithium secondary battery of the present invention exhibits particularly favorable effects when operated at high voltages, where problems such as electrolyte depletion, gas generation, and oxygen desorption from the positive electrode active material become more severe.

[0092] The lithium secondary battery includes a negative electrode, a positive electrode, a separator, and a non-aqueous electrolyte. Specifically, the lithium secondary battery includes a negative electrode, a positive electrode facing the negative electrode, a separator interposed between the negative electrode and the positive electrode, and a non-aqueous electrolyte. The lithium secondary battery may be manufactured by placing an electrode assembly including the negative electrode, a positive electrode facing the negative electrode, and a separator interposed between the negative electrode and the positive electrode in a battery case and then injecting the non-aqueous electrolyte.

[0093] (1) Positive electrode The positive electrode includes a positive electrode active material.

[0094] The positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium. Specifically, it may include a lithium transition metal composite oxide containing at least one transition metal selected from nickel, cobalt, manganese, and aluminum and lithium, preferably a lithium transition metal composite oxide containing a transition metal containing nickel, cobalt, and manganese and lithium.

[0095] For example, as the lithium transition metal composite oxide, there are lithium-manganese-based oxides (e.g., LiMnO2, LiMn2O4, etc.), lithium-cobalt-based oxides (e.g., LiCoO2, etc.), lithium-nickel-based oxides (e.g., LiNiO2, etc.), lithium-nickel-manganese-based oxides (e.g., LiNi 1-Y Mn Y O2 (where 0 < Y < 1), LiMn 2-Z Ni Z O4 (where 0 < Z < 2), etc.), lithium-nickel-cobalt-based oxides (e.g., LiNi 1-Y1 Co Y1 O2 (where 0 < Y1 < 1), etc.), lithium-manganese-cobalt-based oxides (e.g., LiCo 1-Y2 Mn Y2 O2 (where 0 < Y2 < 1), LiMn 2-Z1 Co Z1 O4 (where 0 < Z1 < 2), etc.), lithium-nickel-manganese-cobalt-based oxides (e.g., Li(Ni p Co q Mn r1 )O2 (where 0 < p < 1, 0 < q < 1, 0 < r1 < 1, p + q + r1 = 1) or Li(Ni p1 Co q1 Mn r2 )O4 (where 0 < p1 < 2, 0 < q1 < 2, 0 < r2 < 2, p1 + q1 + r2 = 2), etc.), or lithium-nickel-cobalt-transition metal (M) oxides (e.g., Li(Ni p2 Co q2 Mn r3 M S2)O2 (where M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, and Mo, and p2, q2, r3, and s2 are the atomic fractions of independent elements, respectively, where 0 < p2 < 1, 0 < q2 < 1, 0 < r3 < 1, 0 < s2 < 1, and p2 + q2 + r3 + s2 = 1), etc.) and the like may be mentioned, and any one or two or more of these compounds may be included. Among them, from the viewpoint of enhancing the capacity characteristics and stability of the battery, the lithium transition metal composite oxide is LiCoO2, LiMnO2, LiNiO2, lithium nickel-manganese-cobalt oxide (for example, Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni 0.5 Mn 0.3 Co 0.2 )O2, Li(Ni 0.7 Mn 0.15 Co 0.15 )O2, or Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, etc.), or lithium nickel cobalt aluminum oxide (for example, Li(Ni 0.8 Co 0.15 Al 0.05 )O2, etc.), etc. may be used. Considering the significance of the improvement effect by controlling the types and content ratios of the constituent elements forming the lithium transition metal composite oxide, the lithium transition metal composite oxide is Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni 0.5 Mn 0.3 Co 0.2 )O2, Li(Ni 0.7 Mn 0.15 Co 0.15 )O2, or Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, etc. may be used, and any one or two or more of these mixtures can be used.

[0096] Specifically, the positive electrode active material may include a lithium transition metal oxide represented by the following chemical formula A.

[0097] [Chemical formula A] Li 1+x [Ni a Co b Mn c M 1 d ]O 2+w

[0098] In the chemical formula A, 0≦x≦0.5, a+b+c+d=1, 0.5≦a≦0.7, 0≦b≦0.15, c=1−abd, 0≦d≦0.1, 0≦b / a≦0.2, 1≦a / c≦3, and 0≦w≦1; M 1 is one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo.

[0099] The compound represented by Formula A has a lower nickel content than high-nickel lithium transition metal oxides (e.g., lithium transition metal oxides containing 70 mol % or more of nickel in the transition metal), and therefore requires operation at a high voltage (e.g., 4.35 V or higher) to increase the energy density of the positive electrode. However, when operated at such a high voltage, side reactions in the positive electrode electrolyte become more severe, which can cause problems such as significantly reduced lifespan and storage performance. However, the lithium secondary battery according to the present invention can exhibit excellent long-term lifespan, reduced resistance, and high-temperature storage performance even when operated at a high voltage by organically combining the first and second additives described below.

[0100] In the above chemical formula A, x may be 0≦x≦0.5, specifically 0≦x≦0.2.

[0101] In the chemical formula A, 0.5≦a≦0.7, specifically 0.55≦a≦0.65, may be satisfied.

[0102] In the formula A, 0≦b≦0.15. b corresponds to the molar percentage of Co among the metals excluding lithium in the lithium transition metal oxide represented by the formula A. According to the present invention, a low Co content provides cost benefits, and a relatively high Mn content can improve the structural stability of the positive electrode active material. Specifically, in the formula A, 0≦b≦0.1 may be satisfied.

[0103] In the chemical formula A, 0≦b / a≦0.2. Specifically, in the chemical formula A, 0.05≦b / a≦0.2 may be satisfied.

[0104] In Formula A, c = 1-abd, and 1≦a / c≦3. c corresponds to the molar percentage of Mn among the metals excluding lithium in the lithium transition metal oxide represented by Formula A. According to the present invention, the molar ratio of Ni to Mn is adjusted to 1≦a / c≦3, thereby improving the structural stability of the positive electrode active material. Specifically, it may be 1.5≦a / c≦2.5.

[0105] In the above chemical formula A, M 1 may be understood as an element to be doped into the lithium transition metal oxide, and specifically may be one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo. In this case, d may be 0≦d≦0.1, specifically 0≦d≦0.05.

[0106] In Chemical Formula A, a / (b×c) may be 18 to 50, specifically 18 to 40, and more specifically 20 to 35. When the ratio is within the above range, the contents of nickel, cobalt, and manganese in Chemical Formula A are well-balanced, thereby improving the performance of the cathode coating formed by the additive and simultaneously improving the structural stability of the cathode active material.

[0107] The positive electrode active material may be in the form of particles. Specifically, the positive electrode active material may be in the form of a single particle consisting of one single nodule, or a pseudo-single particle which is a composite of 30 or less nodules. Specifically, the positive electrode active material may be in the form of a pseudo-single particle which is a composite of 2 to 20, more specifically 2 to 10, nodules, or in the form containing single particles and pseudo-single particles. In this case, particle cracking is prevented when an electrode is manufactured using the positive electrode active material, internal cracks due to volumetric expansion / contraction of the nodules during charge / discharge are prevented, and high-temperature life characteristics and high-temperature storage characteristics can be improved.

[0108] The average particle size (D 50 ) may be 1 μm to 10 μm, specifically 2 μm to 8 μm, more specifically 3 μm to 7 μm. When the above range is satisfied, the processability during electrode production is excellent, the electrolyte impregnation is high, the electrochemical properties can be improved, the resistance can be reduced, and the output characteristics can be improved.

[0109] The specific surface area of ​​the positive electrode active material is 0.1 m 2 / g~3.0m 2 / g, specifically 0.3m 2 / g~2.5m 2 / g, more specifically 0.4m 2 / g~1.8m 2 When the above range is satisfied, the rolling characteristics of the electrode can be improved, particle cracking can be reduced, and side reactions with the electrolyte can be suppressed.

[0110] The positive electrode also includes a first additive.

[0111] The first additive may include at least one selected from the group consisting of compounds represented by the following Chemical Formula 1-1 and Chemical Formula 1-2. Specifically, the first additive may include a compound represented by the following Chemical Formula 1-1.

[0112] [ka]

[0113] In the above chemical formula 1-1, Y 11 is nitrogen (N) or R Y11 is a carbon (C) substituted with Y 12 are oxygen (O), sulfur (S), and R Y121 Nitrogen (N) substituted with, or R Y122 and R Y123 is a carbon (C) substituted with Y 13 is nitrogen (N) or R Y13 is a carbon (C) substituted with Y 14 is nitrogen (N) or R Y14 is a carbon (C) substituted with Y 15 is nitrogen (N) or R Y15 and a carbon (C) substituted with Y 11 and Y 15 At least one of the groups is nitrogen (N), and Y 11 , Y 12 , Y 13 , Y 14 , and Y 15 At least one of R is carbon (C), Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 are each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a, Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 At least one of the groups is a substituent represented by the above chemical formula 1-a.

[0114] [Chemical formula 1-2] [ka]

[0115] In the above chemical formula 1-2, Y 21is nitrogen (N) or R Y21 is a carbon (C) substituted with Y 22 is nitrogen (N) or R Y22 is a carbon (C) substituted with Y 23 is nitrogen (N) or R Y23 is a carbon (C) substituted with Y 24 is nitrogen (N) or R Y24 is a carbon (C) substituted with Y 25 is nitrogen (N) or R Y25 and a carbon (C) substituted with Y 21 , Y 22 , Y 23 , Y 24 , and Y 25 At least one of R is carbon (C), Y21 , R Y22 , R Y23 , R Y24 , and R Y25 are each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a, Y21 , R Y22 , R Y23 , R Y24 , and R Y25 At least one of the groups is a substituent represented by the above chemical formula 1-a.

[0116] [Chemical formula 1-a] [ka]

[0117] In the above chemical formula 1-a, L1 is selected from a direct bond, an ester, an ether, and an alkylene group having 1 to 5 carbon atoms; R1 is a direct bond or an alkylene group having 1 to 5 carbon atoms; and R2 is *-CH=CH2 or *-C≡CH, where * is a bonding site.

[0118] Generally, during charge / discharge and storage of lithium secondary batteries, problems such as reactive oxygen desorption from the positive electrode active material, structural collapse of the positive electrode active material due to the desorption of reactive oxygen, and leaching of transition metals can occur. The reactive oxygen reacts with the organic solvent in the electrolyte to generate by-products such as CO, CO2, and HO. Among these, HO decomposes lithium salts to generate HF. This HF promotes the leaching of transition metals and further desorbs oxygen, potentially accelerating the degradation of life and storage performance. These problems are particularly severe when the battery is operated at high voltages.

[0119] To solve these problems, the present invention incorporates the first additive into the positive electrode. The first additive includes at least one compound selected from the compounds represented by Chemical Formula 1-1 and Chemical Formula 1-2. The first additive acts as a Lewis base capable of capturing HF, a Lewis acid, thereby blocking the generation of reactive oxygen by HF. Furthermore, the compound represented by Chemical Formula 1 contains an unsaturated hydrocarbon such as a vinyl group or a propargyl group (a substituent represented by Chemical Formula 1-a) in its structure, which facilitates the formation of a highly durable positive electrode coating.

[0120] Furthermore, the present invention is characterized in that the first additive is contained in the positive electrode rather than in the non-aqueous electrolyte. For example, if the first additive is contained in the non-aqueous electrolyte rather than in the positive electrode, it may be reductively decomposed at the negative electrode, causing an undesired increase in resistance, or the first additive may be consumed at the negative electrode, making it difficult to achieve the effect of forming the positive electrode coating.

[0121] However, if the positive electrode only contains the first additive, the absence of a sulfur (S)-based coating-forming component weakens the structural stability of the positive electrode active material, increasing resistance and making it difficult to achieve the desired effects of improving high-temperature durability and long-term life. Therefore, the present invention is characterized in that the non-aqueous electrolyte contains a second additive that can form an additional positive electrode coating through a chemical reaction with the first additive or the positive electrode coating derived therefrom. Specifically, the non-aqueous electrolyte containing the second additive can form an additional electrode coating by impregnating the positive electrode and allowing the first additive and the second additive to react with each other during an activation process or the like. In this case, the compound represented by Chemical Formula 1-1 and / or the compound represented by Chemical Formula 1-2 contained in the first additive contains sp 2 Because it contains nitrogen (N) with a hybrid orbital, it is advantageous for reaction with the cyclic sulfur oxide contained in the second additive. The electrode coating formed by the reaction of the first additive and the second additive is not only advantageous for the structural stability of the positive electrode, but also effective in reducing resistance. The second additive will be described later.

[0122] In the above chemical formula 1-1, R Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 may be independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a. Specifically, in the chemical formula 1-1, R Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 may be independently selected from hydrogen, a methyl group, and a substituent represented by the following formula 1-a: Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15At least one of R may be a substituent represented by the above chemical formula 1-a. Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 Any one of the groups may be a substituent represented by the chemical formula 1-a, and the remaining groups that are not the substituent represented by the chemical formula 1-a may each independently be hydrogen or an alkyl group having 1 to 3 carbon atoms, specifically hydrogen or a methyl group, more specifically hydrogen.

[0123] In the above chemical formula 1-2, R Y21 , R Y22 , R Y23 , R Y24 , and R Y25 may be independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a. Y21 , R Y22 , R Y23 , R Y24 , and R Y25 may be independently selected from hydrogen, a methyl group, and a substituent represented by the following formula 1-a: Y21 , R Y22 , R Y23 , R Y24 , and R Y25 At least one of R may be a substituent represented by the above chemical formula 1-a. Y21 , R Y22 , R Y23 , R Y24 , and R Y25 Any one of the groups may be a substituent represented by Chemical Formula 1-a, and the remaining groups that are not the substituent represented by Chemical Formula 1-a may be, independently of one another, hydrogen or an alkyl group having 1 to 3 carbon atoms, specifically hydrogen or a methyl group, more specifically hydrogen. In this case, hydrogen or an alkyl group having 1 to 3 carbon atoms does not cause steric hindrance and therefore does not interfere with the positive electrode coating formation effect of the substituent represented by Chemical Formula 1-a or the HF scavenging effect of the nitrogen-containing heteroaromatic compounds of Chemical Formula 1-1 and / or Chemical Formula 1-2.

[0124] [Chemical formula 1-a] [ka]

[0125] In the chemical formula 1-a, L1 may be selected from a direct bond, an ester, an ether, and an alkylene group having 1 to 5 carbon atoms. Specifically, L1 may be a direct bond or an ester. More specifically, L1 may be an ester. When L1 is an ester (*-C(=O)O-*), the bonding positions of the two bonding sites (*) are not particularly limited, but the bonding site adjacent to the oxygen is bonded to R1, and the bonding site adjacent to the carbonyl carbon is a bonding site not bonded to R1, specifically, Y 11 , Y 12 , Y 13 , Y 14 , or Y 15 ;Y 21 , Y 22 , Y 23 , Y 24 , or Y 25 ; may be combined with

[0126] R1 may be a direct bond or an alkylene group having 1 to 5 carbon atoms. Specifically, R1 may be a direct bond or an alkylene group having 1 to 3 carbon atoms.

[0127] R2 may be *-CH=CH2 or *-C≡CH, specifically *-C≡CH.

[0128] The compound represented by Chemical Formula 1-1 may include at least one selected from the group consisting of compounds represented by Chemical Formula 1-1-A, Chemical Formula 1-1-B, Chemical Formula 1-1-C, Chemical Formula 1-1-D, Chemical Formula 1-1-E, and Chemical Formula 1-1-F below, and specifically may include a compound represented by Chemical Formula 1-1-A below.

[0129] [Chemical formula 1-1-A] [ka]

[0130] [Chemical formula 1-1-B] [ka]

[0131] [Chemical formula 1-1-C] [ka]

[0132] [Chemical formula 1-1-D] [ka]

[0133] [Chemical formula 1-1-E] [ka]

[0134] [Chemical formula 1-1-F] [ka]

[0135] In the chemical formulas 1-1-A, 1-1-B, 1-1-C, 1-1-D, 1-1-E, and 1-1-F, R Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , and R Y15 is as defined in Chemical Formula 1-1.

[0136] The compound represented by Chemical Formula 1-2 may include at least one selected from the group consisting of compounds represented by Chemical Formula 1-2-A, Chemical Formula 1-2-B, Chemical Formula 1-2-C, Chemical Formula 1-2-D, and Chemical Formula 1-2-E below.

[0137] [Chemical formula 1-2-A] [ka]

[0138] [Chemical formula 1-2-B] [ka]

[0139] [Chemical formula 1-2-C] [ka]

[0140] [Chemical formula 1-2-D] [ka]

[0141] [Chemical formula 1-2-E] [ka]

[0142] In the chemical formulas 1-2-A, 1-2-B, 1-2-C, 1-2-D, and 1-2-E, R Y21 , R Y22 , R Y23 , R Y24 , and R Y25 is as defined in Chemical Formula 1-2.

[0143] Specifically, the compound represented by Chemical Formula 1-1 may include at least one selected from the group consisting of compounds represented by the following Chemical Formulas 1-1-A1 to 1-1-A4, and more specifically, may include a compound represented by Chemical Formula 1-1-A1.

[0144] [Chemical formula 1-1-A1] [ka]

[0145] [Chemical formula 1-1-A2] [ka]

[0146] [Chemical formula 1-1-A3] [ka]

[0147] [Chemical formula 1-1-A4] [ka]

[0148] The first additive may be contained in the positive electrode in an amount of 0.004 to 8 parts by weight, specifically 0.04 to 4 parts by weight, and more specifically 0.1 to 2 parts by weight, relative to 100 parts by weight of the positive electrode active material. When the amount is within the above range, the capacity-ensuring effect due to the inclusion of the positive electrode active material is sufficiently exhibited, and the positive electrode coating effect due to the first additive can be preferably realized.

[0149] The positive electrode may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, and the positive electrode active material and the first additive may be contained in the positive electrode active material layer.

[0150] The positive electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. Specifically, the positive electrode current collector may include at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, and an aluminum-cadmium alloy, and preferably aluminum.

[0151] The positive electrode current collector usually has a thickness of 3 μm to 500 μm.

[0152] The positive electrode current collector may have a surface with fine irregularities to enhance the bonding strength of the positive electrode active material. For example, the positive electrode current collector may be used in various forms such as a film, sheet, foil, mesh, porous material, foam, or nonwoven fabric.

[0153] The positive electrode active material layer may be disposed on at least one surface of the positive electrode current collector, specifically, on one or both surfaces of the positive electrode current collector.

[0154] The positive electrode active material may be contained in the positive electrode active material layer in an amount of 80% by weight to 99% by weight, preferably 92% by weight to 98.5% by weight, in consideration of sufficient capacity of the positive electrode active material.

[0155] The other positive electrode active materials and the first additive have been described above and will not be described here.

[0156] The positive electrode active material layer may further include a binder and / or a conductive material in addition to the positive electrode active material and the first additive.

[0157] The binder is a component that assists in binding the active material and conductive material, etc., and in binding them to the current collector, and specifically may contain at least one selected from the group consisting of polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, and fluororubber, and preferably polyvinylidene fluoride.

[0158] The binder may be contained in the positive electrode active material layer in an amount of 1 to 20% by weight, preferably 1.2 to 10% by weight, in order to ensure sufficient binding strength between components such as the positive electrode active material.

[0159] The conductive material is used to assist and improve the conductivity of the secondary battery, and is not particularly limited as long as it does not cause chemical changes and is conductive. Specifically, the positive electrode conductive material may include at least one selected from the group consisting of graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives, and preferably includes carbon nanotubes in order to improve conductivity.

[0160] In order to ensure sufficient electrical conductivity, the conductive material may be contained in the positive electrode active material layer in an amount of 1 to 20% by weight, preferably 1.2 to 10% by weight.

[0161] The thickness of the positive electrode active material layer may be 30 μm to 400 μm, preferably 40 μm to 200 μm.

[0162] The positive electrode may be prepared by coating a positive electrode slurry containing a positive electrode active material, and optionally a binder, a conductive material, and a solvent for forming the positive electrode slurry, on the positive electrode current collector, followed by drying and rolling.

[0163] The solvent for forming the positive electrode slurry may include an organic solvent such as N-methyl-2-pyrrolidone (NMP), and the solid content of the positive electrode slurry may be 40% by weight to 90% by weight, specifically 50% by weight to 80% by weight.

[0164] (2) Negative electrode The negative electrode faces the positive electrode.

[0165] The negative electrode includes a negative electrode active material.

[0166] The negative electrode active material is a material capable of reversibly intercalating / deintercalating lithium ions, and may include at least one selected from the group consisting of a carbon-based active material, a metalloid-based active material, and lithium metal, specifically, at least one selected from a carbon-based active material and a metalloid-based active material.

[0167] The carbon-based active material may include at least one selected from the group consisting of artificial graphite, natural graphite, hard carbon, soft carbon, carbon black, graphene, and fibrous carbon, and preferably includes at least one selected from the group consisting of artificial graphite and natural graphite.

[0168] The average particle size (D 50 ) may be 10 μm to 30 μm, preferably 15 μm to 25 μm, in order to ensure structural stability during charge and discharge and reduce side reactions with the electrolyte.

[0169] Specifically, the metalloid-based active material may include at least one metalloid selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; an alloy of lithium and at least one metalloid selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; an oxide of at least one metalloid selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; lithium titanium oxide (LTO); lithium vanadium oxide; and the like.

[0170] More specifically, the metalloid-based active material may include a silicon-based active material.

[0171] The silicon-based active material may include at least one selected from the group consisting of silicon (Si), silicon oxide (SiO x (which may be represented by 0 < x < 2)), and a silicon-carbon composite.

[0172] The average particle size (D 50 ) of the silicon-based active material may be 1 μm to 30 μm, preferably 2 μm to 15 μm, from the viewpoint of achieving structural stability during charge and discharge and reducing side reactions with the electrolyte.

[0173] The negative electrode may include a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector. At this time, the negative electrode active material may be included in the negative electrode active material layer.

[0174] The negative electrode current collector is not particularly limited as long as it does not cause a chemical change in the battery and has high conductivity. Specifically, examples of the negative electrode current collector include copper, stainless steel, aluminum, nickel, titanium, fired carbon, those obtained by surface treatment of copper or stainless steel with carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloys.

[0175] The negative electrode current collector usually has a thickness of 3 μm to 500 μm.

[0176] The negative electrode current collector may strengthen the binding force of the negative electrode active material by forming fine irregularities on its surface. For example, the negative electrode current collector can be used in various forms such as films, sheets, foils, nets, porous bodies, foams, and non-woven fabrics.

[0177] The negative electrode active material layer may be disposed on at least one side of the negative electrode current collector, specifically, on one side or both sides of the negative electrode current collector.

[0178] The negative electrode active material may be contained in the negative electrode active material layer at 60% to 99% by weight, preferably 75% to 9% by weight.

[0179] The negative electrode active material layer may further include a binder and / or a conductive material in addition to the negative electrode active material.

[0180] The binder is used to improve the adhesive strength between the negative electrode active material layer and the negative electrode current collector, thereby improving battery performance. For example, the binder may include at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, and substances in which hydrogen is substituted with Li, Na, Ca, or the like, or may include various copolymers thereof.

[0181] The binder may be contained in the negative electrode active material layer in an amount of 0.5% by weight to 10% by weight, preferably 1% by weight to 5% by weight.

[0182] The conductive material is not particularly limited as long as it does not cause a chemical change in the battery and has conductivity. Examples of the conductive material include graphite such as natural graphite and artificial graphite; carbon black; acetylene black; and KETJENBLACK. (registered trademark) ), carbon black such as channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0183] The conductive material may be contained in the negative electrode active material layer in an amount of 0.5% by weight to 10% by weight, preferably 1% by weight to 5% by weight.

[0184] The thickness of the negative electrode active material layer may be 10 μm to 200 μm, and preferably 20 μm to 150 μm.

[0185] The negative electrode can be prepared by coating at least one surface of a negative electrode current collector with a negative electrode slurry containing a negative electrode active material, a binder, a conductive material, and / or a solvent for forming a negative electrode slurry, followed by drying and rolling.

[0186] The solvent for forming the negative electrode slurry may include, for example, at least one selected from the group consisting of distilled water, N-methyl-2-pyrrolidone (NMP), ethanol, methanol, and isopropyl alcohol, preferably distilled water, in order to facilitate dispersion of the negative electrode active material, binder, and / or conductive material. The solid content of the negative electrode slurry may be 30% by weight to 80% by weight, specifically 40% by weight to 70% by weight.

[0187] (3) Separator The separator can be interposed between the positive electrode and the negative electrode.

[0188] The separator may be a conventional porous polymer film, such as a porous polymer film made of a polyolefin polymer such as an ethylene homocopolymer, a propylene homocopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, either alone or in a laminate, or a conventional porous nonwoven fabric, such as a nonwoven fabric made of a high-melting point glass fiber or polyethylene terephthalate fiber, but is not limited to these. Furthermore, to ensure heat resistance or mechanical strength, a coated separator containing a ceramic component or a polymer material may be used, and may be selectively used as a single-layer or multi-layer structure.

[0189] (4) Nonaqueous electrolyte The non-aqueous electrolyte includes a lithium salt, an organic solvent, and a second additive.

[0190] 1) Lithium salt As the lithium salt used in the present invention, various lithium salts that are commonly used in non-aqueous electrolytes for lithium secondary batteries can be used without any limitation. For example, the lithium salt may contain Li as a cation. + and as an anion, F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , B 10 Cl 10 - , BF2C2O4 - , BC4O8 - , PF4C2O4 - , PF2C4O8 - , (CF3)2PF4 - , (CF3)3PF3 -, (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , CH3SO3 - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , and (CF3CF2SO2)2N - The present invention may include at least one selected from the group consisting of:

[0191] Specifically, the lithium salts include LiCl, LiBr, LiI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 , LiBOB (LiB(C2O4)2), LiCF3SO3, LiFSI (LiN(SO2F)2), LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI (LiN(SO2CF2CF3)2). Specifically, the lithium salt may include at least one selected from the group consisting of LiBF4, LiClO4, LiPF6, LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiFSI (LiN(SO2F)2), and LiBETI (LiN(SO2CF2CF3)2).

[0192] The lithium salt may be contained in the non-aqueous electrolyte at a concentration of 0.5 M to 5 M, specifically 0.8 M to 4 M, and more specifically 0.8 M to 2.0 M. When the concentration of the lithium salt satisfies the above range, the lithium ion transport number (Li +This improves the transference number and dissociation degree of lithium ions, thereby improving the battery's output characteristics.

[0193] 2) Organic solvents The organic solvent is not particularly limited as long as it is a non-aqueous solvent commonly used in lithium secondary batteries and minimizes decomposition due to oxidation reactions during charging and discharging of the secondary battery.

[0194] Specifically, the organic solvent may include at least one selected from the group consisting of cyclic carbonate organic solvents, linear carbonate organic solvents, linear ester organic solvents, and cyclic ester organic solvents.

[0195] Specifically, the organic solvent may include a cyclic carbonate organic solvent, a linear carbonate organic solvent, or a mixture thereof.

[0196] The cyclic carbonate organic solvent is a highly viscous organic solvent that has a high dielectric constant and easily dissociates the lithium salt in the electrolyte. Specifically, the cyclic carbonate organic solvent may include at least one organic solvent selected from the group consisting of ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate. More specifically, the cyclic carbonate organic solvent may include at least one organic solvent selected from the group consisting of ethylene carbonate (EC) and fluoroethylene carbonate (FEC). Even more specifically, the cyclic carbonate organic solvent may include ethylene carbonate (EC).

[0197] The linear carbonate organic solvent is an organic solvent having low viscosity and low dielectric constant, and may specifically include at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate, and ethyl propyl carbonate, more specifically at least one selected from the group consisting of ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), and even more specifically ethyl methyl carbonate (EMC) and diethyl carbonate (DEC). When the linear carbonate organic solvent contains ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), the volume ratio of ethyl methyl carbonate (EMC) to diethyl carbonate (DEC) may be 50:50 to 90:10, specifically 80:20 to 90:10, and more specifically 85:15 to 90:10.

[0198] The organic solvent may be a mixture of a cyclic carbonate organic solvent and a linear carbonate organic solvent. In this case, the cyclic carbonate organic solvent and the linear carbonate organic solvent may be mixed at a volume ratio of 5:95 to 40:60, specifically, a volume ratio of 10:90 to 30:70. When the mixing ratio of the cyclic carbonate organic solvent and the linear carbonate organic solvent satisfies the above range, both high dielectric constant and low viscosity characteristics are satisfied, and excellent ionic conductivity characteristics can be achieved.

[0199] In order to produce an electrolyte having high ionic conductivity, the organic solvent may further contain at least one ester organic solvent selected from the group consisting of linear ester organic solvents and cyclic ester organic solvents in addition to the at least one carbonate organic solvent selected from the group consisting of cyclic carbonate organic solvents and linear carbonate organic solvents.

[0200] Specifically, the linear ester organic solvent may include at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate.

[0201] The cyclic ester organic solvent may specifically include at least one selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone.

[0202] Meanwhile, the organic solvent may further include, as needed, any organic solvent commonly used in non-aqueous electrolytes, for example, at least one of an ether-based organic solvent, a glyme-based organic solvent, and a nitrile-based organic solvent.

[0203] The ether solvent may be any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether, ethyl propyl ether, 1,3-dioxolane (DOL), and 2,2-bis(trifluoromethyl)-1,3-dioxolane (TFDOL), or a mixture of two or more of these, but is not limited thereto.

[0204] The glyme-based solvent has a higher dielectric constant and lower surface tension than linear carbonate-based organic solvents and is less reactive with metals, and may include at least one selected from the group consisting of dimethoxyethane (glyme, DME), diethoxyethane, diglyme, triglyme, and tetraglyme (TEGDME), but is not limited thereto.

[0205] The nitrile solvent may be one or more selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile, but is not limited thereto.

[0206] 4) Additives The non-aqueous electrolyte contains a second additive.

[0207] The second additive includes a cyclic sulfur oxide. The cyclic sulfur oxide can form an additional positive electrode coating by chemically reacting with the first additive or a positive electrode coating derived therefrom. Specifically, the nitrogen-containing heteroaromatic compound in the first additive or a positive electrode coating component derived therefrom can open the ring of the cyclic sulfur oxide-based compound to form an additional positive electrode coating that can improve the high-temperature durability and long-term life performance of the positive electrode. In addition, the compounds of Chemical Formula 1-1 and / or Chemical Formula 1-2 contained in the first additive are sp 2 Since the structure contains nitrogen having a hybrid orbital, the reaction with the cyclic sulfur oxide can occur stably.

[0208] The present invention is characterized by including a first additive in the positive electrode and a second additive in the non-aqueous electrolyte. This allows for smooth formation of a positive electrode coating without unnecessary consumption due to reduction at the negative electrode or increased negative electrode resistance. For example, if both the first and second additives are included in the non-aqueous electrolyte, the first and second additives react and are consumed during reduction at the negative electrode, preventing the improvement of high-temperature durability by strengthening the positive electrode coating. Furthermore, if both the first and second additives are included in the positive electrode, the viscosity of the slurry containing them increases during positive electrode production, resulting in poor electrode quality. On the other hand, if the positive electrode includes the second additive and the non-aqueous electrolyte includes the first additive, a side reaction with Li by-products causes uneven formation of a surface coating on the positive electrode active material.

[0209] The cyclic sulfur oxides may include, for example, propane sultone, propene sultone, ethylene sulfate, ethylene sulfite, methylene methane disulfonate in their structure.

[0210] Specifically, the cyclic sulfur oxide may include at least one selected from the group consisting of compounds represented by the following chemical formulas 2-a, 2-b, 2-c, 2-d, 2-e, 2-f, and 2-g. More specifically, the cyclic sulfur oxide may include a compound represented by the following chemical formula 2-a.

[0211] [Chemical formula 2-a] [ka]

[0212] In the above chemical formula 2-a, X 11 and X 12 are, independently of each other, *-O-* or *-C(R X11 )(R X12 )-* and X 11 and X 12 At the same time, *-C(R X11 )(R X12)-*, and R 11 , R 14 , R X11 , and R X12 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 R is an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; 12 and R 13 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 10 to 10 alkynyl groups, halogen groups, or substituents represented by the following chemical formula 3, or R 12 and R 13 are each formed by a condensed ring to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, a cycloalkynyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, with the proviso that R 12 and R 13 When R forms an aryl group having 6 to 20 carbon atoms, 11 and R 14 is absent, i is an integer of 1 or 2, and * is a binding site.

[0213] [Chemical formula 3] [ka]

[0214] In the above chemical formula 3, L 61 and L 62 are each independently a direct bond or an alkylene group having 1 to 5 carbon atoms, A is a substituent represented by the following chemical formula 4, and X 61 and X 62 are, independently of each other, *-O-* or *-C(R X61 )(R X62 )-* and X 61 and X 62 At the same time, *-C(R X61 )(R X62 )-*, and R 63 , RX61 , and R X62 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 R is an alkynyl group having 10 to 10 carbon atoms, or a halogen atom; 61 and R 62 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 alkynyl group having 10 to 10 carbon atoms, or halogen group, or R 62 and R 63 are fused together to form a condensed ring, and are a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, or a cycloalkynyl group having 5 to 20 carbon atoms, k is an integer of 1 or 2, and * is a bonding site.

[0215] [Chemical formula 4] [ka]

[0216] In the above Chemical Formula 4, l is an integer of 1 or 2, and * is a binding site.

[0217] In the above chemical formula 2-a, X 11 and X 12 are, independently of each other, *-O-* or *-C(R X11 )(R X12 )-* and X 11 and X 12 At the same time, *-C(R X11 )(R X12 )-*. For example, X 11 and X 12 are both *-O-*;X 11 is *-C(R X11 )(R X12 )-* and X 12 may be *-O-*.

[0218] R 11 , R 14 , RX11 , and R X12 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 to 10 alkynyl groups, and halogen (which may be F, Cl, Br, or I), specifically selected independently from each other from hydrogen, methyl group, *-CH=CH2, *-C≡CH, and fluorine (F).

[0219] R 12 and R 13 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 Up to 10 alkynyl groups may be halogen groups, and specifically may be, independently of one another, hydrogen, methyl, *-CH=CH2, *-C≡CH, or fluorine (F).

[0220] Or, R 12 and R 13 may be condensed together to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, a cycloalkynyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. 12 and R 13 When R forms an aryl group having 6 to 20 carbon atoms, 11 and R 14 does not exist. For example, R 12 and R 13 may form a condensed ring to form a benzene group, in which case R 11 and R 14 does not have to exist.

[0221] Or, R 12 and R 13 may be, independently of each other, a substituent represented by the above-mentioned Chemical Formula 3. In the above-mentioned Chemical Formula 3, L 61 and L 62may each independently represent a direct bond or an alkylene group having 1 to 5 carbon atoms, specifically may each independently represent a direct bond or an alkylene group having 1 to 3 carbon atoms, more specifically may each independently represent a direct bond or a methylene group, and even more specifically may each be a methylene group.

[0222] X 61 and X 62 are, independently of each other, *-O-* or *-C(R X61 )(R X62 )-* and X 61 and X 62 At the same time, *-C(R X61 )(R X62 )-*. For example, X 61 and X 62 are both *-O-*;X 61 is *-C(R X61 )(R X62 )-* and X 62 may be *-O-*.

[0223] R 63 , R X61 , and R X62 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 10 to 10 alkynyl groups, or halogen, and specifically may be, independently of each other, hydrogen, methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0224] R 61 and R 62 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 10 to 10 alkynyl groups, or halogen groups, and specifically may be, independently of one another, hydrogen, methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0225] Or, R62 and R 63 may be condensed together to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, or a cycloalkynyl group having 5 to 20 carbon atoms.

[0226] [Chemical formula 2-b] [ka]

[0227] In the above chemical formula 2-b, R 21 , R 22 , R 23 , and R 24 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 R may be an alkynyl group having 1 to 10 carbon atoms, or a halogen atom. 21 , R 22 , R 23 , and R 24 may be, independently of each other, hydrogen, a methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0228] [Chemical formula 2-c] [ka]

[0229] In the above chemical formula 2-c, R 31 , R 32 , R 33 , and R 34 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 R may be an alkynyl group having 1 to 10 carbon atoms, or a halogen atom. 31 , R 32 , R 33 , and R 34 may be, independently of each other, hydrogen, a methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0230] [Chemical formula 2-d] [ka]

[0231] In the above chemical formula 2-d, R 41 , R 42 , R 43 , and R 46 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 R is an alkynyl group having 1 to 10 carbon atoms, or a halogen atom. 41 , R 42 , R 43 , and R 46 may be, independently of each other, hydrogen, a methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0232] R 44 and R 45 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 alkynyl groups, or halogen, or R 44 and R 45 are each formed by a condensed ring to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, a cycloalkynyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, with the proviso that R 44 and R 45 When R forms an aryl group having 6 to 20 carbon atoms, 43 and R 46 does not exist.

[0233] Specifically, R 44 and R 45 may be, independently of each other, hydrogen, a methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0234] Or, R44 and R 45 may be condensed together to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, a cycloalkynyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. 44 and R 45 When R forms an aryl group having 6 to 20 carbon atoms, 43 and R 46 does not exist. For example, R 44 and R 45 may form a condensed ring to form a benzene group, in which case R 43 and R 46 does not have to exist.

[0235] [Chemical formula 2-e] [ka]

[0236] In the above chemical formula 2-e, X 51 and X 52 are, independently of each other, *-O-* or *-C(R X51 )(R X52 )-* and X 51 and X 52 At the same time, *-C(R X51 )(R X52 )-*, and R 51 , R 52 , R 53 , R 54 , R 55 , R 56 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 10 to 10 alkynyl groups, or halogen, and j is an integer of 1 or 2.

[0237] For example, X 51 and X 52 are both *-O-*;X 51 is *-C(R X51 )(R X52)-* and X 52 may be *-O-*.

[0238] Also, R 51 , R 52 , R 53 , R 54 , R 55 , R 56 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 R is an alkynyl group having 1 to 10 carbon atoms, or a halogen atom. 51 , R 52 , R 53 , R 54 , R 55 , R 56 may be, independently of each other, hydrogen, a methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0239] [Chemical formula 2-f] [ka]

[0240] In the above chemical formula 2-f, X 71 and X 72 are, independently of each other, *-O-* or *-C(R X71 )(R X72 )-* and X 71 and X 72 At the same time, *-C(R X71 )(R X72 )-*, not X 73 and X 74 are, independently of each other, *-O-* or *-C(R X73 )(R X74 )-* and X 73 and X 74 At the same time, *-C(R X73 )(R X74 )-*, and R X71 , R X72 , R X73 , R X74are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 10 to 10 alkynyl groups, or halogen, m and n are each independently an integer of 1 or 2, and * is the bonding site.

[0241] For example, X 71 and X 72 are both *-O-*;X 71 is *-C(R X71 )(R X72 )-* and X 72 may be *-O-*. Also, for example, X 73 and X 74 are both *-O-*;X 73 is *-C(R X73 )(R X74 )-* and X 74 may be *-O-*.

[0242] Also, R X71 , R X72 , R X73 , R X74 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 R is an alkynyl group having 1 to 10 carbon atoms, or a halogen atom. X71 , R X72 , R X73 , R X74 may be, independently of each other, hydrogen, a methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0243] [Chemical formula 2-g] [ka]

[0244] In the above chemical formula 2-g, R 81 , R 82 , R 83 , and R 84are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms. 2 ~10 Alkenyl group , carbon number 2 R may be an alkynyl group having 1 to 10 carbon atoms, or a halogen atom. 81 , R 82 , R 83 , and R 84 may be, independently of each other, hydrogen, a methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0245] Specifically, the cyclic sulfur oxide may include at least one compound selected from the group consisting of compounds represented by the following chemical formulas 2-a-1 to 2-a-25, 2-b-1, 2-c-1, 2-d-1, 2-e-1, 2-e-2, 2-f-1, and 2-g-1. For example, the compound represented by chemical formula 2-a may include at least one compound selected from the group consisting of compounds represented by the following chemical formulas 2-a-1 to 2-a-25. The compound represented by chemical formula 2-b may include a compound represented by chemical formula 2-b-1. The compound represented by chemical formula 2-c may include a compound represented by chemical formula 2-c-1. The compound represented by chemical formula 2-d may include a compound represented by chemical formula 2-d-1. The compound represented by chemical formula 2-e may include at least one compound selected from the group consisting of compounds represented by chemical formulas 2-e-1 and 2-e-2. The compound represented by the chemical formula 2-f may include a compound represented by the chemical formula 2-f-1.

[0246] More specifically, the cyclic sulfur oxide may include at least one selected from the group consisting of compounds represented by the following chemical formulas 2-a-1 to 2-a-10, 2-b-1, 2-c-1, 2-d-1, 2-e-1, 2-e-2, and 2-f-1.

[0247] More specifically, the cyclic sulfur oxide may include at least one selected from the group consisting of compounds represented by the following chemical formulas 2-a-1, 2-a-2, 2-a-3, 2-a-4, 2-a-6, 2-a-10, and 2-b-1. Even more specifically, the cyclic sulfur oxide may include at least one selected from the group consisting of compounds represented by the following chemical formulas 2-a-1, 2-a-4, 2-a-10, and 2-b-1. Even more specifically, the cyclic sulfur oxide may include at least one selected from the group consisting of compounds represented by the following chemical formulas 2-a-1, 2-a-10, and 2-b-1. Even more specifically, the cyclic sulfur oxide may include a compound represented by the following chemical formula 2-a-10.

[0248] [Chemical formula 2-a-1] [ka]

[0249] [Chemical formula 2-a-2] [ka]

[0250] [Chemical formula 2-a-3] [ka]

[0251] [Chemical formula 2-a-4] [ka]

[0252] [Chemical formula 2-a-5] [ka]

[0253] [Chemical formula 2-a-6]

change

[0254] [Chemical formula 2-a-7]

change

[0255] [Chemical formula 2-a-8]

change

[0256] [Chemical formula 2-a-9]

change

[0257] [Chemical formula 2-a-10]

change

[0258] [Chemical formula 2-a-11]

change

[0259] [Chemical formula 2-a-12]

change

[0260] [Chemical formula 2-a-13]

change

[0261] [Chemical formula 2-a-14]

change

[0262] [Chemical formula 2-a-15]

change

[0263] [Chemical formula 2-a-16]

change

[0264] [Chemical formula 2-a-17]

change

[0265] [Chemical formula 2-a-18]

change

[0266] [Chemical formula 2-a-20]

change

[0267] [Chemical formula 2-a-21]

change

[0268] [Chemical formula 2-a-22]

change

[0269] [Chemical formula 2-a-23]

change

[0270] [Chemical formula 2-a-24]

change

[0271] [Chemical formula 2-a-25]

change

[0272] [Chemical formula 2-b-1]

change

[0273] [Chemical formula 2-c-1]

change

[0274] [Chemical formula 2-d-1]

change

[0275] [Chemical formula 2-e-1]

change

[0276] [Chemical formula 2-e-2]

change

[0277] [Chemical formula 2-f-1]

change

[0278] [Chemical formula 2-g-1]

change

[0279] The second additive may be included in the non-aqueous electrolyte in an amount of 0.01 wt % to 10 wt %, specifically 0.05 wt % to 7 wt %, more specifically 0.1 wt % to 2 wt %, and more specifically 0.5 wt % to 1.5 wt %. When the second additive is used in the above content range, it can sufficiently capture reactive oxygen generated during initial activation and prevent the risk of an increase in resistance when added in an excessive amount.

[0280] The weight ratio of the first additive contained in the positive electrode to the second additive contained in the non-aqueous electrolyte may be 5:95 to 95:5, specifically 10:90 to 92:8, more specifically 30:70 to 70:30, and even more specifically 40:60 to 60:40. When the weight ratio is as described above, the effects of using the first additive and the second additive in combination are achieved in a balanced manner, and as a result, the effects of improving the high-temperature life performance, high-temperature storage performance, and safety of the lithium secondary battery can be preferably exhibited.

[0281] The additive may further include an additional additive (which may be referred to as a third additive) in addition to the first and second additives. The additional additive may be included in the non-aqueous electrolyte to prevent the non-aqueous electrolyte from decomposing and causing the collapse of the negative electrode in a high-power environment, or to improve low-temperature high-rate discharge characteristics, high-temperature stability, prevent overcharging, and suppress battery expansion at high temperatures.

[0282] Specifically, the additional additive may be at least one selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, succinonitrile, adiponitrile, ethylene sulfate, LiBOB (Lithium bis-(oxalato)borate), TMSPa (3-trimethoxysilanyl-propyl-N-aniline), and TMSPi (Tris(trimethylsilyl)Phosphite), and specifically may be vinylene carbonate.

[0283] The additional additive may be included in the non-aqueous electrolyte in an amount of 0.1 wt % to 15 wt %.

[0284] The external shape of the lithium secondary battery of the present invention is not particularly limited, and may be a cylindrical shape using a can, a square shape, a pouch shape, a coin shape, or the like.

[0285] The present invention will be described in more detail below with reference to specific examples. However, the following examples are merely illustrative for understanding the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the present description and technical concept, and it goes without saying that such changes and modifications fall within the scope of the appended claims.

[0286] Examples and Comparative Examples Example 1 (Production of non-aqueous electrolyte) The organic solvent used was a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 20:70:10.

[0287] A non-aqueous electrolyte was prepared by adding LiPF6 as a lithium salt and the compound represented by Formula 2-a-1 as a second additive to the organic solvent.

[0288] The LiPF6 was contained in the non-aqueous electrolyte at a molar concentration of 1.2M.

[0289] The compound represented by the chemical formula 2-a-1 was contained in the non-aqueous electrolyte at 1 wt %.

[0290] (Lithium secondary battery manufacturing) Cathode active material (Li[Ni 0.6 Co 0.1 Mn 0.3 ]O2), a first additive (a compound represented by chemical formula 1-1-A1), a conductive material (carbon nanotubes), and a binder (polyvinylidene fluoride) were added to a solvent, N-methyl-2-pyrrolidone (NMP), in a weight ratio of 97.00:0.08:1.52:1.40 to prepare a positive electrode slurry (solid content 72 wt%). The positive electrode slurry was applied to one side of a 12 μm-thick positive electrode current collector (Al thin film), dried, and roll-pressed to form a positive electrode active material layer (thickness: 115 μm), which served as the positive electrode.

[0291] The negative electrode active material (a mixture of graphite and silicon-carbon composite in a weight ratio of 95:5) and conductive Materials and A negative electrode slurry (solid content 54 wt%) was prepared by adding binders (styrene-butadiene rubber and carboxymethyl cellulose) to distilled water as a solvent in a weight ratio of 94.9:0.5:4.6. The negative electrode slurry was applied to one side of a negative electrode current collector (Cu thin film) with a thickness of 6 μm, dried, and roll-pressed to form a negative electrode active material layer (thickness: 160 μm), which served as the negative electrode.

[0292] A polyethylene porous film separator was interposed between the positive electrode and the negative electrode in a dry room, and the non-aqueous electrolyte was then injected to prepare a lithium secondary battery.

[0293] Example 2 A non-aqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that the compound represented by Chemical Formula 2-a-4 was added to the non-aqueous electrolyte in an amount of 1 wt % instead of the compound represented by Chemical Formula 2-a-1 as the second additive.

[0294] Example 3 A non-aqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that, as the second additive, the compound represented by Chemical Formula 2-b-1 was added to the non-aqueous electrolyte in an amount of 1 wt % instead of the compound represented by Chemical Formula 2-a-1.

[0295] Example 4 A non-aqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that the compound represented by Chemical Formula 2-a-10 was added to the non-aqueous electrolyte in an amount of 1 wt % instead of the compound represented by Chemical Formula 2-a-1 as the second additive.

[0296] Example 5 A non-aqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that the compound represented by Chemical Formula 2-a-2 was added to the non-aqueous electrolyte in an amount of 1 wt % instead of the compound represented by Chemical Formula 2-a-1 as the second additive.

[0297] Example 6 A non-aqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that the compound represented by Chemical Formula 2-a-3 was added to the non-aqueous electrolyte in an amount of 1 wt % instead of the compound represented by Chemical Formula 2-a-1 as the second additive.

[0298] Example 7 A non-aqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that the compound represented by Chemical Formula 2-a-6 was added to the non-aqueous electrolyte in an amount of 1 wt % instead of the compound represented by Chemical Formula 2-a-1 as the second additive.

[0299] Comparative Example 1 (Production of non-aqueous electrolyte) A non-aqueous electrolyte was prepared in the same manner as in Example 1, except that the second additive (the compound represented by chemical formula 2-a-1) was not added to the non-aqueous electrolyte.

[0300] (Lithium secondary battery manufacturing) Cathode active material (Li[Ni 0.6 Co 0.1 Mn 0.3 ]O2), a conductive material (carbon nanotubes), and a binder (polyvinylidene fluoride) were added to a solvent, N-methyl-2-pyrrolidone (NMP), in a weight ratio of 97.00:1.56:1.44 to prepare a positive electrode slurry (solid content 72 wt%). The positive electrode slurry was applied to one side of a 12 μm-thick positive electrode current collector (Al thin film), dried, and roll-pressed to form a positive electrode active material layer (thickness: 115 μm), which served as the positive electrode.

[0301] A lithium secondary battery was produced in the same manner as in Example 1, except that the non-aqueous electrolyte and positive electrode produced above were used.

[0302] Comparative Example 2 (Production of non-aqueous electrolyte) A non-aqueous electrolyte was prepared in the same manner as in Example 1, except that the compound represented by Chemical Formula 1-1-A1 was added to the non-aqueous electrolyte in an amount of 1 wt % instead of the second additive (the compound represented by Chemical Formula 2-a-1).

[0303] (Lithium secondary battery manufacturing) A positive electrode was produced in the same manner as in Comparative Example 1.

[0304] A lithium secondary battery was produced in the same manner as in Example 1, except that the non-aqueous electrolyte and positive electrode produced above were used.

[0305] Comparative Example 3 (Production of non-aqueous electrolyte) A non-aqueous electrolyte was produced in the same manner as in Example 1.

[0306] (Lithium secondary battery manufacturing) A positive electrode was produced in the same manner as in Comparative Example 1.

[0307] A lithium secondary battery was produced in the same manner as in Example 1, except that the non-aqueous electrolyte and positive electrode produced above were used.

[0308] Comparative Example 4 (Production of non-aqueous electrolyte) A non-aqueous electrolyte was prepared in the same manner as in Example 1, except that the compound represented by Formula 1-1-A1 was further added to the non-aqueous electrolyte in an amount of 1 wt %.

[0309] (Lithium secondary battery manufacturing) A positive electrode was produced in the same manner as in Comparative Example 1.

[0310] A lithium secondary battery was produced in the same manner as in Example 1, except that the non-aqueous electrolyte and positive electrode produced above were used.

[0311] Comparative Example 5 (Production of non-aqueous electrolyte) A non-aqueous electrolyte was produced in the same manner as in Comparative Example 1.

[0312] (Lithium secondary battery manufacturing) A lithium secondary battery was produced in the same manner as in Example 1, except that the non-aqueous electrolyte produced above was used.

[0313] Comparative Example 6 (Production of non-aqueous electrolyte) A non-aqueous electrolyte was produced in the same manner as in Comparative Example 2.

[0314] (Lithium secondary battery manufacturing) Cathode active material (Li[Ni 0.6 Co 0.1 Mn 0.3]O2), a second additive (a compound represented by formula 2-a-1), a conductive material (carbon nanotubes), and a binder (polyvinylidene fluoride) were added to a solvent, N-methyl-2-pyrrolidone (NMP), in a weight ratio of 97.00:0.08:1.52:1.40 to prepare a positive electrode slurry (solid content 72 wt%). The positive electrode slurry was applied to one side of a 12 μm-thick positive electrode current collector (Al thin film), dried, and roll-pressed to form a positive electrode active material layer (thickness: 115 μm), which served as the positive electrode.

[0315] A lithium secondary battery was produced in the same manner as in Example 1, except that the non-aqueous electrolyte and positive electrode produced above were used.

[0316] Experimental example Experimental example 1: Evaluation of high-temperature cycle performance The lithium secondary batteries of Examples 1 to 7 and Comparative Examples 1 to 6 manufactured as described above were charged to 4.35 V, 1 / 40 C under CC / CV, 0.33 C conditions at 45°C, and then discharged to 2.0 V under CC, 0.33 C conditions using an electrochemical charger / discharger, and 300 charge / discharge cycles were carried out.

[0317] (1) Capacity maintenance rate The capacity retention rate was calculated using the following formula, and the results are shown in Table 1 below.

[0318] Capacity retention rate (%) = {(discharge capacity after 300 cycles / discharge capacity after 1 cycle)} × 100

[0319] (2) Resistance increase rate After one charge / discharge cycle, the discharge capacity after one cycle was measured using an electrochemical charge / discharge device, and after adjusting the SOC to 50%, a 2.5C pulse was applied for 10 seconds, and the initial resistance was calculated from the difference in voltage before and after the pulse application.

[0320] After 300 cycles of charge and discharge, the resistance after 300 cycles was calculated in the same manner as above, and the resistance increase rate was calculated using the following formula. The results are shown in Table 1 below.

[0321] Resistance increase rate (%) = (resistance after 300 cycles - initial resistance) / initial resistance x 100

[0322] (3) Amount of gas generated After 300 charge / discharge cycles, the amount of gas generated in the lithium secondary battery was measured by GC-FID / TCD, and the results are shown in Table 1 below.

[0323] [Table 1]

[0324] Referring to Table 1, it can be seen that the lithium secondary batteries of Examples 1 to 7, which are lithium secondary batteries manufactured by combining a positive electrode containing the first additive and a non-aqueous electrolyte containing the second additive, have a higher capacity retention rate, a lower resistance increase rate, and a lower amount of gas generation during charge and discharge in a high-temperature cycle compared to Comparative Examples 1 to 6.

[0325] Experimental example 2: Evaluation of high-temperature storage performance The lithium secondary batteries of Examples 1 to 7 and Comparative Examples 1 to 6 prepared above were initially charged and discharged at 25° C. under CC / CV and 0.33 C conditions to 4.35 V and 1 / 40 C, and then discharged at 0.33 C to 2.0 V. Thereafter, they were charged at 25° C. under CC / CV and 0.33 C conditions to 4.35 V and 1 / 40 C, and then stored at 60° C. for 12 weeks.

[0326] (1) Capacity maintenance rate After 12 weeks of storage, the lithium secondary battery was charged at 25° C. under CC / CV, 0.33 C conditions to 4.35 V, 1 / 40 C, and then discharged at 0.33 C to 2.0 V, and the discharge capacity was measured.

[0327] The capacity retention rate was evaluated using the following formula, and the results are shown in Table 2 below.

[0328] Capacity retention rate (%) = (discharge capacity after 12 weeks of storage / initial discharge capacity) x 100

[0329] (2) Resistance increase rate After the initial charge / discharge, the capacity was confirmed at room temperature, and then the battery was charged to 50% SOC based on the discharge capacity and discharged at a current of 2.5 C for 10 seconds. The resistance was measured from the voltage drop difference at this time and recorded as the initial resistance. After storing at 60°C for 12 weeks, the resistance was measured in the same manner and recorded as the final resistance. The resistance increase rate was calculated using the following formula. The results are shown in Table 2 below.

[0330] Resistance increase rate (%) = (final resistance - initial resistance) / (initial resistance) x 100

[0331] (3) Amount of gas generated After 12 weeks of storage, the amount of gas generated in the lithium secondary battery was measured by GC-FID / TCD, and the results are shown in Table 2 below.

[0332] [Table 2]

[0333] Referring to Table 2 above, it can be seen that the lithium secondary batteries of Examples 1 to 7, which are lithium secondary batteries manufactured by combining a positive electrode containing the first additive and a non-aqueous electrolyte containing the second additive, have a higher capacity retention rate, a lower resistance increase rate, and a lower amount of gas generated during high-temperature storage compared to Comparative Examples 1 to 6.

Claims

1. a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte; the positive electrode includes a positive electrode active material and a first additive; the non-aqueous electrolyte includes a lithium salt, an organic solvent, and a second additive; The first additive includes at least one selected from the group consisting of compounds represented by the following Chemical Formula 1-1 and Chemical Formula 1-2: The second additive comprises a cyclic sulfur oxide-based compound, [Chemical formula 1-1] 【Chemistry 1】 In the above chemical formula 1-1, Y １１ is nitrogen (N), or R Ｙ１１ and Y is a carbon (C) substituted with １２ is oxygen (O), sulfur (S), R Ｙ１２１ Nitrogen (N) substituted with, or R Ｙ１２２ and R Ｙ１２３ and Y is a carbon (C) substituted with １３ is nitrogen (N), or R Ｙ１３ and Y is a carbon (C) substituted with １４ is nitrogen (N), or R Ｙ１４ and Y is a carbon (C) substituted with １５ is nitrogen (N), or R Ｙ１５ is a carbon (C) substituted with Y １１ and Y １５ At least one of Y is nitrogen (N), １１ , Y １２ , Y １３ , Y １４ , and Y １５ at least one of is carbon (C), R Ｙ１１ , R Ｙ１２１ , R Ｙ１２２ , R Ｙ１２３ , R Ｙ１３ , R Ｙ１４ , and R Ｙ１５ are each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a, wherein R Ｙ１１ , R Ｙ１２１ , R Ｙ１２２ , R Ｙ１２３ , R Ｙ１３ , R Ｙ１４ , and R Ｙ１５ at least one of the following is a substituent represented by the chemical formula 1-a; [Chemical formula 1-2] 【Chemistry 2】 In the above chemical formula 1-2, Y ２１ is nitrogen (N), or R Ｙ２１ and Y is a carbon (C) substituted with ２２ is nitrogen (N), or R Ｙ２２ and Y is a carbon (C) substituted with ２３ is nitrogen (N), or R Ｙ２３ and Y is a carbon (C) substituted with ２４ is nitrogen (N), or R Ｙ２４ and Y is a carbon (C) substituted with ２５ is nitrogen (N), or R Ｙ２５ is a carbon (C) substituted with Y ２１ , Y ２２ , Y ２３ , Y ２４ , and Y ２５ at least one of is carbon (C), R Ｙ２１ , R Ｙ２２ , R Ｙ２３ , R Ｙ２４ , and R Ｙ２５ are each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following chemical formula 1-a, wherein R Ｙ２１ , R Ｙ２２ , R Ｙ２３ , R Ｙ２４ , and R Ｙ２５ at least one of the following is a substituent represented by the chemical formula 1-a; [Chemical formula 1-a] 【Transformation 3】 In the above chemical formula 1-a, L １ is selected from a direct bond, an ester, an ether, and an alkylene group having 1 to 5 carbon atoms; R １ is a direct bond or an alkylene group having 1 to 5 carbon atoms, and R ２ is *-CH=CH ２ or *-C≡CH, where * is the attachment site.

2. The compound represented by Chemical Formula 1-1 includes at least one selected from the group consisting of compounds represented by Chemical Formula 1-1-A, Chemical Formula 1-1-B, Chemical Formula 1-1-C, Chemical Formula 1-1-D, Chemical Formula 1-1-E, and Chemical Formula 1-1-F. The lithium secondary battery according to claim 1, [Chemical formula 1-1-A] 【Chemistry 4】 [Chemical formula 1-1-B] 【Transformation 5】 [Chemical formula 1-1-C] 【Transformation 6】 [Chemical formula 1-1-D] 【Transformation 7】 [Chemical formula 1-1-E] 【Transformation 8】 [Chemical formula 1-1-F] 【Chemistry 9】 (In the above chemical formulas 1-1-A, 1-1-B, 1-1-C, 1-1-D, 1-1-E, and 1-1-F, R Ｙ１１ , R Ｙ１２１ , R Ｙ１２２ , R Ｙ１２３ , R Ｙ１３ , R Ｙ１４ , and R Ｙ１５ is as defined in Chemical Formula 1-1.)

3. The compound represented by Chemical Formula 1-2 includes at least one selected from the group consisting of compounds represented by Chemical Formula 1-2-A, Chemical Formula 1-2-B, Chemical Formula 1-2-C, Chemical Formula 1-2-D, and Chemical Formula 1-2-E: [Chemical formula 1-2-A] 【Chemistry 10】 [Chemical formula 1-2-B] 【Chemistry 11】 [Chemical formula 1-2-C] 【Chemistry 12】 [Chemical formula 1-2-D] 【Chemistry 13】 [Chemical formula 1-2-E] 【Chemistry 14】 (In the above chemical formulas 1-2-A, 1-2-B, 1-2-C, 1-2-D, and 1-2-E, R Ｙ２１ , R Ｙ２２ , R Ｙ２３ , R Ｙ２４ , and R Ｙ２５ is as defined in Chemical Formula 1-2.)

4. 2. The lithium secondary battery according to claim 1, wherein the first additive comprises the compound represented by Chemical Formula 1-1.

5. The lithium secondary battery according to claim 1, wherein the compound represented by Chemical Formula 1-1 includes at least one selected from the group consisting of compounds represented by the following Chemical Formulas 1-1-A1 to 1-1-A4. [Chemical formula 1-1-A1] 【Chemistry 15】 [Chemical formula 1-1-A2] 【Chemistry 16】 [Chemical formula 1-1-A3] 【Chemistry 17】 [Chemical formula 1-1-A4] [Chemistry 18]

6. The lithium secondary battery of claim 1, wherein the first additive is contained in the positive electrode in an amount of 0.004 to 8 parts by weight based on 100 parts by weight of the positive electrode active material.

7. 2. The lithium secondary battery of claim 1, wherein the first additive is contained in the positive electrode in an amount of 0.04 to 4 parts by weight based on 100 parts by weight of the positive electrode active material.

8. The lithium secondary battery according to claim 1, wherein the cyclic sulfur oxide compound includes at least one compound selected from the group consisting of compounds represented by the following chemical formulas 2-a, 2-b, 2-c, 2-d, 2-e, 2-f, and 2-g: [Chemical formula 2-a] 【Chemistry 19】 In the chemical formula 2-a, X １１ and X １２ are each independently *-O-* or *-C(R Ｘ１１ ) (R Ｘ１２ )-*, and X １１ and X １２ At the same time, *-C(R Ｘ１１ ) (R Ｘ１２ )-*, R １１ , R １４ , R Ｘ１１ , and R Ｘ１２ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom; R １２ and R １３ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, a halogen group, or a substituent represented by the following chemical formula 3, or R １２ and R １３ are condensed together to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, a cycloalkynyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, provided that R １２ and R １３ When R forms an aryl group having 6 to 20 carbon atoms, １１ and R １４ does not exist, i is an integer of 1 or 2; * is the binding site, [Chemical formula 2-b] 【Chemistry 20】 In the above chemical formula 2-b, R ２１ , R ２２ , R ２３ , and R ２４ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom; [Chemical formula 2-c] 【Chemistry 21】 In the above chemical formula 2-c, R ３１ , R ３２ , R ３３ , and R ３４ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom; [Chemical formula 2-d] 【Chemistry 22】 In the above chemical formula 2-d, R ４１ , R ４２ , R ４３ , and R ４６ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom; R ４４ and R ４５ are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom, or R ４４ and R ４５ are condensed together to form a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, a cycloalkynyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, provided that R ４４ and R ４５ When R forms an aryl group having 6 to 20 carbon atoms, ４３ and R ４６ does not exist, [Chemical formula 2-e] 【Chemistry 23】 In the above chemical formula 2-e, X ５１ and X ５２ are each independently *-O-* or *-C(R Ｘ５１ ) (R Ｘ５２ )-*, and X ５１ and X ５２ At the same time, *-C(R Ｘ５１ ) (R Ｘ５２ )-*, R ５１ , R ５２ , R ５３ , R ５４ , R ５５ , R ５６ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom; j is an integer of 1 or 2, [Chemical formula 2-f] 【Chemistry 24】 In the above chemical formula 2-f, X ７１ and X ７２ are each independently *-O-* or *-C(R Ｘ７１ ) (R Ｘ７２ )-*, and X ７１ and X ７２ At the same time, *-C(R Ｘ７１ ) (R Ｘ７２ )-*, X ７３ and X ７４ are each independently *-O-* or *-C(R Ｘ７３ ) (R Ｘ７４ )-*, and X ７３ and X ７４ At the same time, *-C(R Ｘ７３ ) (R Ｘ７４ )-*, R Ｘ７１ , R Ｘ７２ , R Ｘ７３ , R Ｘ７４ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom; m and n are each independently an integer of 1 or 2; * is the binding site, [Chemical formula 2-g] 【Chemistry 25】 In the above chemical formula 2-g, R ８１ , R ８２ , R ８３ , and R ８４ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom; [Chemical formula 3] 【Chemistry 26】 In the above Chemical Formula 3, L ６１ and L ６２ are each independently a direct bond or an alkylene group having 1 to 5 carbon atoms, A is a substituent represented by the following chemical formula 4: X ６１ and X ６２ are each independently *-O-* or *-C(R Ｘ６１ ) (R Ｘ６２ )-*, and X １１ and X １２ At the same time, *-C(R Ｘ６１ ) (R Ｘ６２ )-*, R ６３ , R Ｘ６１ , and R Ｘ６２ are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen atom; R ６１ and R ６２ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen group, or R ６２ and R ６３ are each formed by a condensed ring, and are a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkenyl group having 5 to 20 carbon atoms, or a cycloalkynyl group having 5 to 20 carbon atoms, k is an integer of 1 or 2; * is the binding site, [Chemical formula 4] 【Chemistry 27】 In the above formula 4, l is an integer of 1 or 2, and * is a binding site.

9. 2. The lithium secondary battery according to claim 1, wherein the cyclic sulfur oxide-based compound comprises at least one compound selected from the group consisting of compounds represented by the following Chemical Formulas 2-a-1 to 2-a-25, 2-b-1, 2-c-1, 2-d-1, 2-e-1, 2-e-2, 2-f-1, and 2-g-1. [Chemical formula 2-a-1] 【Chemistry 28】 [Chemical formula 2-a-2] 【Chemistry 29】 [Chemical formula 2-a-3] 【Transformation 30】 [Chemical formula 2-a-4] 【Chemistry 31】 [Chemical formula 2-a-5] 【Chemistry 32】 [Chemical formula 2-a-6] 【Transformation 33】 [Chemical formula 2-a-7] 【Transformation 34】 [Chemical formula 2-a-8] 【Chemistry 35】 [Chemical formula 2-a-9] 【Transformation 36】 [Chemical formula 2-a-10] 【Chemistry 37】 [Chemical formula 2-a-11] 【Transformation 38】 [Chemical formula 2-a-12] 【Chemistry 39】 [Chemical formula 2-a-13] 【Chemistry 40】 [Chemical formula 2-a-14] 【Chemistry 41】 [Chemical formula 2-a-15] 【Chemistry 42】 [Chemical formula 2-a-16] 【Chemistry 43】 [Chemical formula 2-a-17] 【Chemistry 44】 [Chemical formula 2-a-18] 【Chemistry 45】 [Chemical formula 2-a-19] 【Chemistry 46】 [Chemical formula 2-a-20] 【Chemistry 47】 [Chemical formula 2-a-21] 【Chemistry 48】 [Chemical formula 2-a-22] 【Chemistry 49】 [Chemical formula 2-a-23] [Transformation 50] [Chemical formula 2-a-24] 【Chemistry 51】 [Chemical formula 2-a-25] 【Chemistry 52】 [Chemical formula 2-b-1] 【Chemistry 53】 [Chemical formula 2-c-1] 【Chemistry 54】 [Chemical formula 2-d-1] 【Transformation 55】 [Chemical formula 2-e-1] 【Transformation 56】 [Chemical formula 2-e-2] 【Chemistry 57】 [Chemical formula 2-f-1] 【Chemistry 58】 [Chemical formula 2-g-1] 【Chemistry 59】

10. 2. The lithium secondary battery according to claim 1, wherein the second additive is contained in the non-aqueous electrolyte in an amount of 0.01% by weight to 10% by weight.

11. 2. The lithium secondary battery according to claim 1, wherein the positive electrode active material comprises a lithium transition metal oxide represented by the following chemical formula A: [Chemical formula A] Li １＋ｘ [Ni ａ Co ｂ Mn ｃ M １ ｄ ]O ２＋ｗ (In the chemical formula A, 0≦x≦0.5, a+b+c+d=1, 0.5≦a≦0.7, 0≦b≦0.15, c=1−a−b−d, 0≦d≦0.1, 0≦b / a≦0.2, 1≦a / c≦3, and 0≦w≦1; M １ is one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo.

12. the negative electrode includes a negative electrode active material, 2. The lithium secondary battery according to claim 1, wherein the negative electrode active material comprises at least one selected from the group consisting of a carbon-based active material and a silicon-based active material.

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