Lithium secondary battery

Abstract

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

Description

Technical Field

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

[0002] In recent years, the application of lithium secondary batteries in power storage for large equipment such as automobiles and energy storage devices, as well as power supply for electronic equipment such as electrical, electronic, communication, and computer equipment has rapidly expanded, leading to an increasing demand for secondary batteries with high capacity, high output, and high stability.

[0003] Lithium secondary batteries generally include a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, an electrolyte used as a medium for transporting lithium ions, and a separator. In this case, as the negative electrode active material, a carbon-based active material, a silicon-based active material, etc. can be used. In addition, as the positive electrode active material, lithium transition metal oxides such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium nickel cobalt manganese composite oxide can be used.

[0004] At the same time, high operating voltages are recently required to achieve high energy density in lithium secondary batteries. However, during such high-voltage operation, electrolyte depletion, gas generation, and transition metal dissolution of the positive electrode active material due to oxidative decomposition reactions of the electrolyte lead to reduced battery life performance, storage performance, and durability. Summary of the Invention

[0005] [Technical Issues]

[0006] The present invention is intended to overcome the above limitations, and therefore, one aspect of the present invention provides a lithium secondary battery having high-temperature durability, long life performance, and high voltage stability by forming a high-durability film on the surface of a positive electrode.

[0007] [Technical solution]

[0008] [1] According to one aspect of the present invention, a lithium secondary battery is provided, which includes a positive electrode, a negative electrode, a separator disposed 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 formula 1-1 and formula 1-2, and the second additive includes a cyclic sulfur oxide compound.

[0009] [Formula 1-1]

[0010]

[0011] In the above equation 1-1, Y 11 Nitrogen (N) or R Y11 Substituted carbon (C), Y 12oxygen (O), sulfur (S), a carbon (C) substituted with R Y121 nitrogen (N), or a carbon (C) substituted with R Y122 and R Y123 nitrogen (N), or a carbon (C) substituted with R 13 nitrogen (N), or a carbon (C) substituted with R Y13 nitrogen (N), or a carbon (C) substituted with R 14 nitrogen (N), or a carbon (C) substituted with R Y14 nitrogen (N), or a carbon (C) substituted with R 15 nitrogen (N), or a carbon (C) substituted with R Y15 nitrogen (N), or a carbon (C) substituted with R 11 nitrogen (N), or a carbon (C) substituted with R 15 nitrogen (N), or a carbon (C) substituted with R 11 nitrogen (N), or a carbon (C) substituted with R 12 nitrogen (N), or a carbon (C) substituted with R 13 nitrogen (N), or a carbon (C) substituted with R 14 nitrogen (N), or a carbon (C) substituted with R 15 nitrogen (N), or a carbon (C) substituted with R Y11 nitrogen (N), or a carbon (C) substituted with R Y121 nitrogen (N), or a carbon (C) substituted with R Y122 nitrogen (N), or a carbon (C) substituted with R Y123 nitrogen (N), or a carbon (C) substituted with R Y13 nitrogen (N), or a carbon (C) substituted with R Y14 nitrogen (N), or a carbon (C) substituted with R Y15 nitrogen (N), or a carbon (C) substituted with R Y11 nitrogen (N), or a carbon (C) substituted with R Y121 nitrogen (N), or a carbon (C) substituted with R Y122 nitrogen (N), or a carbon (C) substituted with R Y123 nitrogen (N), or a carbon (C) substituted with R Y13 nitrogen (N), or a carbon (C) substituted with R Y14 nitrogen (N), or a carbon (C) substituted with R Y15 at least one of R

[0012] [Formula 1-2]

[0013]

[0014] In the above formula 1-2, Y 21 is nitrogen (N) or a carbon (C) substituted with R Y21 is nitrogen (N) or a carbon (C) substituted with R 22 is nitrogen (N) or a carbon (C) substituted with R Y22 is nitrogen (N) or a carbon (C) substituted with R 23 is nitrogen (N) or a carbon (C) substituted with R Y23 is nitrogen (N) or a carbon (C) substituted with R 24 is nitrogen (N) or a carbon (C) substituted with R Y24 is nitrogen (N) or a carbon (C) substituted with R 25 is nitrogen (N) or a carbon (C) substituted with R Y25 is nitrogen (N) or a carbon (C) substituted with R 21 is nitrogen (N) or a carbon (C) substituted with R 22 is nitrogen (N) or a carbon (C) substituted with R 23 is nitrogen (N) or a carbon (C) substituted with R 24 is nitrogen (N) or a carbon (C) substituted with R 25At least one of them is carbon (C), and R Y21 、R Y22 、R Y23 、R Y24 and R Y25 Each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms and a substituent represented by the following formula 1-a, wherein R Y21 、R Y22 、R Y23 、R Y24 or R Y25 At least one of them is a substituent represented by Formula 1-a.

[0015] [Formula 1-a]

[0016]

[0017] In the above 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, wherein * is a bonding site.

[0018] [2] The present invention provides a lithium secondary battery as described in [1] above, wherein the compound represented by the above formula 1-1 includes at least one selected from the group consisting of compounds represented by the following formulas 1-1-A, 1-1-B, 1-1-C, 1-1-D, 1-1-E and 1-1-F.

[0019] [Formula 1-1-A]

[0020]

[0021] [Formula 1-1-B]

[0022]

[0023] [Formula 1-1-C]

[0024]

[0025] [Formula 1-1-D]

[0026]

[0027] [Formula 1-1-E]

[0028]

[0029] [Formula 1-1-F]

[0030]

[0031] In Formula 1-1-A, Formula 1-1-B, Formula 1-1-C, Formula 1-1-D, Formula 1-1-E, and Formula 1-1-F, R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 and R Y15 As defined in Formula 1-1.

[0032] [3] The present invention provides a lithium secondary battery according to at least one of [1] or [2] above, wherein the compound represented by the above formula 1-2 includes at least one selected from the group consisting of compounds represented by the following formulas 1-2-A, 1-2-B, 1-2-C, 1-2-D, and 1-2-E:

[0033] [Formula 1-2-A]

[0034]

[0035] [Formula 1-2-B]

[0036]

[0037] [Formula 1-2-C]

[0038]

[0039] [Formula 1-2-D]

[0040]

[0041] [Formula 1-2-E]

[0042]

[0043] In Formula 1-2-A, Formula 1-2-B, Formula 1-2-C, Formula 1-2-D, and Formula 1-2-E, R Y21 、R Y22 、R Y23 、R Y24 and R Y25 As defined in Formula 1-2.

[0044] [4] The present invention provides the lithium secondary battery described in at least one of [1] to [3] above, wherein the first additive includes a compound represented by Formula 1-1.

[0045] [5] The present invention provides a lithium secondary battery according to at least one of [1] to [4] above, wherein the compound represented by Formula 1-1 includes at least one selected from the group consisting of compounds represented by the following Formulas 1-1-A1 to 1-1-A4.

[0046] [Formula 1-1-A1]

[0047]

[0048] [Formula 1-1-A2]

[0049]

[0050] [Formula 1-1-A3]

[0051]

[0052] [Formula 1-1-A4]

[0053]

[0054] [6] The present invention provides the lithium secondary battery described in at least one of [1] to [5] above, wherein the positive electrode contains 0.004 to 8 parts by weight of the first additive relative to 100 parts by weight of the positive electrode active material.

[0055] [7] The present invention provides the lithium secondary battery described in at least one of [1] to [6] above, wherein the positive electrode contains 0.04 to 4 parts by weight of the first additive relative to 100 parts by weight of the positive electrode active material.

[0056] [8] The present invention provides a lithium secondary battery as described in at least one of the above [1] to [7], wherein the cyclic sulfur oxide compound includes at least one selected from the group consisting of compounds represented by the following formula 2-a, formula 2-b, formula 2-c, formula 2-d, formula 2-e, formula 2-f and formula 2-g.

[0057] [Formula 2-a]

[0058]

[0059] In formula 2-a, X 11 and X 12 Each independently is *-O-* or *-C(R X11 )(R X12 )-*, but X 11 and X 12 Not all are *-C(R X11 )(R X12 )-*,

[0060] R 11 、R 14 、R X11 and R X12 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen,

[0061] R 12 and R 13 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl 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 formula 3, or R 12 and R 13 together to form a fused ring to provide 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 when R 12 and R 13 When forming an aromatic group having 6 to 20 carbon atoms, R 11 and R 14 does not exist,

[0062] i is an integer of 1 or 2, and

[0063] * is the bonding site,

[0064] [Formula 2-b]

[0065]

[0066] In 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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen,

[0067] [Formula 2-c]

[0068]

[0069] In 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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen,

[0070] [Formula 2-d]

[0071]

[0072] In formula 2-d, R 41 、R 42 、R 43 and R 46are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, and

[0073] R 44 and R 45 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, or R 44 and R 45 together to form a fused ring to provide 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 when R 44 and R 45 When forming an aromatic group having 6 to 20 carbon atoms, R 43 and R 46 does not exist,

[0074] [Formula 2-e]

[0075]

[0076] In formula 2-e, X 51 and X 52 Each independently is *-O-* or *-C(R X51 )(R X52 )-*, but X 51 and X 52 Not all are *-C(R X51 )(R X52 )-*,

[0077] R 51 、R 52 、R 53 、R 54 、R 55 and R 56 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, and

[0078] j is an integer of 1 or 2,

[0079] [Formula 2-f]

[0080]

[0081] In formula 2-f, X 71 and X 72 Each independently is *-O-* or *-C(R X71 )(R X72 )-*, but X 71and X 72 Not all are *-C(R X71 )(R X72 )-*,

[0082] X 73 and X 74 Each independently is *-O-* or *-C(R X73 )(R X74 )-*, but X 73 and X 74 Not all are *-C(R X73 )(R X74 )-*,

[0083] R X71 、R X72 、R X73 and R X74 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen,

[0084] m and n are each independently an integer of 1 or 2, and

[0085] * is the bonding site,

[0086] [Formula 2-g]

[0087]

[0088] In 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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen,

[0089] [Formula 3]

[0090]

[0091] In formula 3, L 61 and L 62 are each independently a direct bond or an alkylene group having 1 to 5 carbon atoms,

[0092] A is a substituent represented by the following formula 4,

[0093] X 61 and X 62 Each independently is *-O-* or *-C(R X61 )(R X62 )-*, but X 11 and X 12 Not all are *-C(RX61 )(R X62 )-*,

[0094] R 63 、R X61 and R X62 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen,

[0095] R 61 and R 62 is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl 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 together to form a fused ring to provide 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,

[0096] k is an integer of 1 or 2, and

[0097] * is the bonding site,

[0098] [Formula 4]

[0099]

[0100] Wherein, in Formula 4, l is an integer of 1 or 2, and * is a bonding site.

[0101] [9] The present invention provides a lithium secondary battery as described in at least one of the above [1] to [8], wherein the cyclic sulfur oxide compound includes at least one selected from the group consisting of compounds represented by the following formulae 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.

[0102] [Formula 2-a-1]

[0103]

[0104] [Formula 2-a-2]

[0105]

[0106] [Formula 2-a-3]

[0107]

[0108] [Formula 2-a-4]

[0109]

[0110] [Formula 2-a-5]

[0111]

[0112] [Formula 2-a-6]

[0113]

[0114] [Formula 2-a-7]

[0115]

[0116] [Formula 2-a-8]

[0117]

[0118] [Formula 2-a-9]

[0119]

[0120] [Formula 2-a-10]

[0121]

[0122] [Formula 2-a-11]

[0123]

[0124] [Formula 2-a-12]

[0125]

[0126] [Formula 2-a-13]

[0127]

[0128] [Formula 2-a-14]

[0129]

[0130] [Formula 2-a-15]

[0131]

[0132] [Formula 2-a-16]

[0133]

[0134] [Formula 2-a-17]

[0135]

[0136] [Formula 2-a-18]

[0137]

[0138] [Formula 2-a-19]

[0139]

[0140] [Formula 2-a-20]

[0141]

[0142] [Formula 2-a-21]

[0143]

[0144] [Formula 2-a-22]

[0145]

[0146] [Formula 2-a-23]

[0147]

[0148] [Formula 2-a-24]

[0149]

[0150] [Formula 2-a-25]

[0151]

[0152] [Formula 2-b-1]

[0153] [Formula 2-c-1]

[0154]

[0155] [Formula 2-d-1]

[0156]

[0157] [Formula 2-e-1]

[0158]

[0159] [Formula 2-e-2]

[0160]

[0161] [Formula 2-f-1]

[0162]

[0163] [Formula 2-g-1]

[0164]

[0165]

[10] The present invention provides the lithium secondary battery described in at least one of [1] to [9] above, wherein the non-aqueous electrolyte includes the second additive in an amount of 0.01 wt % to 10 wt %.

[0166]

[11] The present invention provides a lithium secondary battery according to at least one of [1] to

[10] above, wherein the positive electrode active material comprises a lithium composite transition metal oxide represented by the following formula A.

[0167] [Formula A]

[0168] Li 1+x [Ni a Co b Mn c M 1 d ]O 2+w

[0169] In the above 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,

[0170] M 1 It is at least one 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.

[0171]

[12] The present invention provides a lithium secondary battery according to at least 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.

[0172] [Beneficial Effects]

[0173] The lithium secondary battery of the present invention comprises a nitrogen-containing heteroaromatic compound of a specific formula (Formula 1-1 and / or Formula 1-2) as a first additive in the positive electrode, and comprises a cyclic sulfur oxide compound as a second additive contained in the non-aqueous electrolyte. According to the present invention, by including a first additive in the positive electrode, a film that improves oxidation durability is pre-formed, and by a second additive that can chemically react with the first additive to decompose to form an additional film, the inhibitory effect on positive electrode oxygen desorption and the interface safety of the positive electrode-non-aqueous electrolyte are ensured, and therefore, a lithium secondary battery showing excellent life performance, high temperature storage performance and reduced resistance can be achieved. The lithium secondary battery of the present invention can show even more ideal effects, especially during high voltage operation in which electrolyte depletion, gas generation and oxygen desorption of the positive active material are aggravated. DETAILED DESCRIPTION

[0174] It should be understood that the terms or words used in the description and claims of the present invention should not be understood as limited to the meanings in conventional dictionaries, but should be interpreted as meanings consistent with the context of the relevant technology and the technical ideas of the present invention based on the principle of allowing inventors to define terms in order to interpret their inventions in the best way.

[0175] In this document, it should also be understood that the terms "comprising", "providing" and "having" indicate the presence of the features, numbers, steps, elements or combinations thereof described herein, but do not preclude the presence or addition of one or more other features, numbers, steps, elements or combinations thereof.

[0176] Meanwhile, before describing the present invention, unless otherwise specified in the present invention, "*" represents a connecting portion (bonding site) between the same or different atoms or terminals of a formula.

[0177] In addition, as used herein, "a" and "b" in the description of "a to b carbon atoms" represent the number of carbon atoms contained in a particular functional group. That is, the functional group may include "a" to "b" carbon atoms. For example, the term "alkyl group having 1 to 5 carbon atoms" means an alkyl group including 1 to 5 carbon atoms, i.e., CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, (CH3)2CHCH2-, CH3CH2CH2CH2CH2-, or (CH3)2CHCH2CH2-, etc.

[0178] Furthermore, as used herein, an alkyl, alkenyl, alkynyl, alkoxy, aryl, or heteroaryl group can be substituted or unsubstituted. Unless otherwise defined, the term “substituted” means that at least one hydrogen atom bonded to a carbon atom is replaced by an element other than a hydrogen atom, for example, by 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 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 halogenated aryl group having 6 to 20 carbon atoms.

[0179] Hereinafter, the present invention will be described in more detail.

[0180] lithium secondary batteries

[0181] The present invention relates to a lithium secondary battery.

[0182] The lithium secondary battery of the present invention includes a positive electrode, a negative electrode, a separator disposed 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 formula 1-1 and formula 1-2, and the second additive includes a cyclic sulfur oxide compound.

[0183] [Formula 1-1]

[0184]

[0185] In the above equation 1-1, Y 11 Nitrogen (N) or R Y11 Substituted carbon (C), Y 12 For oxygen (O), sulfur (S), R Y121 Substituted nitrogen (N), or R Y122 and R Y123 Substituted carbon (C), Y 13 Nitrogen (N) or R Y13 Substituted carbon (C), Y 14 Nitrogen (N) or R Y14 substituted carbon (C), and Y 15 Nitrogen (N) or R Y15 Substituted carbon (C), wherein Y 11 and Y 15 At least one of is nitrogen (N), and Y11 、Y 12 、Y 13 、Y 14 or Y 15 At least one of is carbon (C), and R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 and R Y15 Each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms and a substituent represented by the following formula 1-a, wherein R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 or R Y15 At least one of them is a substituent represented by Formula 1-a.

[0186] [Formula 1-2]

[0187]

[0188] In the above equation 1-2, Y 21 Nitrogen (N) or R Y21 Substituted carbon (C), Y 22 Nitrogen (N) or R Y22 Substituted carbon (C), Y 23 Nitrogen (N) or R Y23 Substituted carbon (C), Y 24 Nitrogen (N) or R Y24 substituted carbon (C), and Y 25 Nitrogen (N) or R Y25 Substituted carbon (C), wherein Y 21 、Y 22 、Y 23 、Y 24 or Y 25 At least one of them is carbon (C), and R Y21 、R Y22 、R Y23 、R Y24 and R Y25 Each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms and a substituent represented by the following formula 1-a, wherein R Y21 、R Y22 、R Y23 、R Y24 or R Y25 At least one of them is a substituent represented by Formula 1-a.

[0189] [Formula 1-a]

[0190]

[0191] In the above 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, wherein * is a bonding site.

[0192] The lithium secondary battery of the present invention comprises a nitrogen-containing heteroaromatic compound of a specific formula (Formula 1-1 and / or Formula 1-2) as a first additive in the positive electrode, and comprises a cyclic sulfur oxide compound as a second additive contained in the non-aqueous electrolyte. According to the present invention, by including a first additive in the positive electrode, a film that improves oxidation durability is pre-formed, and by a second additive that can chemically react with the first additive to decompose to form an additional film, the inhibitory effect on positive electrode oxygen desorption and the interface safety of the positive electrode-non-aqueous electrolyte are ensured, and therefore, a lithium secondary battery showing excellent life performance, high temperature storage performance and reduced resistance can be achieved. The lithium secondary battery of the present invention can show even more ideal effects, especially during high voltage operation in which electrolyte depletion, gas generation and oxygen desorption of the positive active material are aggravated.

[0193] The lithium secondary battery comprises a negative electrode, a positive electrode, a separator and a non-aqueous electrolyte. Specifically, the lithium secondary battery comprises a negative electrode, a positive electrode facing the negative electrode, a separator disposed between the negative electrode and the positive electrode, and a non-aqueous electrolyte. The lithium secondary battery can be manufactured by inserting an electrode assembly comprising a negative electrode, a positive electrode facing the negative electrode, and a separator disposed between the negative electrode and the positive electrode into a battery case and then injecting the non-aqueous electrolyte.

[0194] (1) Positive electrode

[0195] The positive electrode contains a positive electrode active material.

[0196] The positive electrode active material is a compound that can reversibly insert and release lithium, and can specifically include, for example, a lithium transition metal composite oxide containing lithium and at least one transition metal selected from nickel, cobalt, manganese and aluminum, preferably a lithium transition metal composite oxide containing lithium and a transition metal containing nickel, cobalt and manganese.

[0197] For example, lithium transition metal composite oxides may include lithium manganese-based oxides (e.g., LiMnO2, LiMn2O4), lithium cobalt-based oxides (e.g., LiCoO2), lithium nickel-based oxides (e.g., LiNiO2), lithium nickel manganese-based oxides (e.g., LiNi 1-Y Mn Y O2 (where 0 <Y<1)、LiMn 2-z Ni zO4 (where 0 <Z<2))、锂镍钴基氧化物(例如LiNi 1-Y1 Co Y1 O2 (where 0 <Y1<1))、锂锰钴基氧化物(例如LiCo 1-Y2 Mn Y2 O2 (where 0 <Y2<1)、LiMn 2-z1 Co z1 O4 (where 0 <Z1<2))、锂镍锰钴基氧化物(例如Li(Ni p Co q Mn r1 )O2(where 0 <p<1、0<q<1、0<r1<1且p+q+r1=1)或Li(Ni p1 Co q1 Mn r2 )O4(where 0 <p1<2、0<q1<2、0<r2<2且p1+q1+r2=2)或锂镍钴过渡金属(M)氧化物(例如,Li(Ni p2 Co q2 Mn r3 M s2 )O2 (wherein M is selected from Al, Fe, V, Cr, Ti, Ta, Mg and Mo, and p2, q2, r3 and s2 are the atomic fractions of each independent element, wherein 0 <p2<1、0<q2<1、0<r3<1、0<s2<1和p2+q2+r3+s2=1)),并且可以包括其中任何一种或其两种以上的混合物。在这些材料中,从能够提高电池的容量和稳定性的观点出发,锂过渡金属复合氧化物可以是LiCoO2、LiMnO2、LiNiO2、锂镍锰钴氧化物(例如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), lithium nickel cobalt aluminum oxide (such as Li(Ni 0.8 Co 0.15 Al 0.05 )O2). Considering the significant improvement effect produced by controlling the types and content ratios of the elements constituting the lithium transition metal composite oxide, the lithium transition metal composite oxide may be 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, and any one of them or a mixture of two or more thereof may be used.

[0198] Specifically, the positive electrode active material may include a lithium transition metal oxide represented by Formula A below.

[0199] [Formula A]

[0200] Li 1+x [Ni a Co b Mn c M 1 d ]O 2+w

[0201] In the above 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 It is at least one 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.

[0202] Since the nickel content of the compound represented by the above formula A is lower than that of high-nickel lithium transition metal oxide (for example, a lithium transition metal oxide having a nickel content of 70 mol % or more in the transition metal), it is necessary to operate at a high voltage (for example, above 4.35 V) to increase the energy density of the positive electrode. When operating at a high voltage, the positive electrode electrolyte side reaction is aggravated, resulting in a decrease in life performance and storage performance. However, by organically combining the first additive and the second additive, the lithium secondary battery of the present invention can exhibit excellent long life performance, reduced resistance and high temperature storage performance even when operating at a high voltage, which will be described later.

[0203] In the above formula A, x may satisfy the following condition: 0≤x≤0.5, specifically 0≤x≤0.2.

[0204] In the above formula A, a may satisfy the following condition: 0.5≤a≤0.7, specifically 0.55≤a≤0.65.

[0205] In the above formula A, b satisfies the following condition: 0 ≤ b ≤ 0.15. b corresponds to the molar percentage of Co in the metal other than lithium in the lithium transition metal oxide represented by formula A, and according to the present invention, reducing the Co content can provide cost benefits, while relatively increasing the proportion of Mn can improve the structural stability of the positive electrode active material. Specifically, in the above formula A, b can satisfy the following condition: 0 ≤ b ≤ 0.1.

[0206] In the above formula A, a and b satisfy the following condition: 0≤b / a≤0.2. Specifically, in the above formula A, a and b may satisfy the following condition: 0.05≤b / a≤0.2.

[0207] In Formula A above, a, b, c, and d satisfy the following conditions: c = 1-abd and 1 ≤ a / c ≤ 3. c corresponds to the molar percentage of Mn in the metal other than 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, a and c can satisfy the following conditions: 1.5 ≤ a / c ≤ 2.5.

[0208] In the above formula A, M 1 It can be considered as a doping element of lithium transition metal oxide, specifically, M 1 It may be at least one 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 satisfies the following condition: 0≤d≤0.1, specifically 0≤d≤0.05.

[0209] In the above formula A, a / (b×c) may be in the range of 18 to 50, specifically 18 to 40, more specifically 20 to 35. Within the above range, the contents of nickel, cobalt, and manganese in formula A are coordinately adjusted to simultaneously achieve improved performance (achieved by forming a positive electrode film from the additives) and improved structural stability of the positive electrode active material.

[0210] The positive electrode active material may be in a granular form. Specifically, the positive electrode active material is in the form of a single particle formed by a single nodule, or in the form of a quasi-single particle as a composite of less than 30 nodules, specifically in the form of a quasi-single particle as a composite of 2 to 20 nodules, more specifically 2 to 10 nodules, or in the form of both a single particle and a quasi-single particle. In this case, particle breakage is prevented when preparing an electrode of the positive electrode active material, and internal cracks caused by volume expansion / contraction of the nodules during charge / discharge are prevented, thereby improving high temperature life characteristics and high temperature storage characteristics.

[0211] The average particle size of the positive electrode active material (D 50 ) can be 1 μm to 10 μm, specifically 2 μm to 8 μm, more specifically 3 μm to 7 μm. When the above range is met, excellent processability in electrode manufacturing can be achieved, enhanced electrolyte impregnation can improve electrochemical performance, and reduced resistance and improved output characteristics can be obtained.

[0212] The specific surface area of ​​the positive electrode active material can be 0.1m 2 / g to 3.0m 2 / g, specifically 0.3m 2 / g to 2.5m 2 / g, more specifically 0.4m 2 / g to 1.8m 2 When the above range is satisfied, the rolling characteristics of the electrode can be improved, and particle breakage can be reduced, thereby suppressing a side reaction with the electrolyte.

[0213] In addition, the positive electrode contains a first additive.

[0214] The first additive may include at least one selected from the group consisting of compounds represented by the following Formula 1-1 and Formula 1-2. Specifically, the first additive may include a compound represented by the following Formula 1-1.

[0215]

[0216] In the above equation 1-1, Y 11 Nitrogen (N) or R Y11 Substituted carbon (C), Y 12 For oxygen (O), sulfur (S), R Y121 Substituted nitrogen (N), or R Y122 and R Y123 Substituted carbon (C), Y 13 Nitrogen (N) or R Y13 Substituted carbon (C), Y 14 Nitrogen (N) or R Y14 substituted carbon (C), and Y 15 Nitrogen (N) or R Y15 Substituted carbon (C), wherein Y 11 and Y 15 At least one of is nitrogen (N), and Y 11 、Y 12 、Y 13 、Y 14 or Y 15 At least one of is carbon (C), and R Y11 、R Y121 、R Y122 、R Y123 、RY13 , R Y14 , and R Y15 are each independently selected from the group consisting of hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following formula 1-a, wherein R Y11 , R Y121 , R Y122 , R Y123 , R Y13 , R Y14 , or R Y15 at least one of R 21 is a substituent represented by formula 1-a.

[0217] [Formula 1-2]

[0218]

[0219] In the above formula 1-2, Y Y21 is nitrogen (N) or carbon (C) substituted with R 22 is nitrogen (N) or carbon (C) substituted with R Y22 is nitrogen (N) or carbon (C) substituted with R 23 is nitrogen (N) or carbon (C) substituted with R Y23 is nitrogen (N) or carbon (C) substituted with R 24 is nitrogen (N) or carbon (C) substituted with R Y24 is nitrogen (N) or carbon (C) substituted with R 25 , wherein at least one of Y Y25 , Y 21 , Y 22 , Y 23 , Y 24 , or Y 25 is carbon (C), and R Y21 , R Y22 , R Y23 , R Y24 , and R Y25 are each independently selected from the group consisting of hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by the following formula 1-a, wherein R Y21 , R Y22 , R Y23 , R Y24 , or R Y25 at least one of R

[0220] [Formula 1-a]

[0221]

[0222] In the above 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 *-CºCH, wherein * is a bonding site.

[0223] Typically, under conditions such as charge / discharge and storage of lithium secondary batteries, active oxygen desorption from the positive electrode active material, structural collapse of the positive electrode active material caused by active oxygen desorption, and elution of transition metals may occur. This active oxygen reacts with the organic solvent of the electrolyte to produce byproducts of CO, CO2, and HO. In particular, HO decomposes lithium salts to produce HF, and HF promotes the elution of transition metals and the re-desorption of oxygen, leading to accelerated deterioration of life performance and storage performance. In particular, these problems are further exacerbated under high voltage operation.

[0224] In order to overcome these limitations, the present invention includes a first additive in the positive electrode. The first additive includes at least one compound selected from the compounds represented by Formula 1-1 and Formula 1-2, and acts as a Lewis base capable of capturing HF (which is a Lewis acid), thereby preventing HF from generating reactive oxygen. In addition, the compound represented by Formula 1 contains an unsaturated hydrocarbon group (a substituent represented by Formula 1-a), such as a vinyl group or a propargyl group, in the structure, and thus can be conducive to the formation of a highly durable positive electrode film.

[0225] In addition, in the present invention, the first additive is contained in the positive electrode rather than in the non-aqueous electrolyte. For example, when the first additive is contained in the non-aqueous electrolyte rather than in the positive electrode, it is difficult to achieve the above-mentioned positive electrode film formation effect because reduction and decomposition at the negative electrode may lead to an undesirable increase in resistance or consumption of the first additive at the negative electrode.

[0226] At the same time, simply including the first additive in the positive electrode hardly causes the desired high temperature durability and long life performance improvement effect, because in the absence of the formation of sulfur (S)-based film components, the resistance of the positive electrode active material increases and the structural stability decreases. Therefore, the present invention includes a second additive that is capable of forming an additional positive electrode film by chemically reacting with the first additive or the positive electrode film derived therefrom in a non-aqueous electrolyte. Specifically, the non-aqueous electrolyte containing the second additive is impregnated with the positive electrode, and the first additive and the second additive can react with each other during the activation process to form an additional electrode film. In this case, the compound represented by formula 1-1 and / or the compound represented by formula 1-2 contained in the first additive contains a compound having sp in the structure. 2 The nitrogen (N) of the hybrid orbital is therefore conducive to reacting with the cyclic sulfur oxide contained in the second additive. The electrode film formed by the reaction of the first and second additives is beneficial to the structural stability of the positive electrode and effectively reduces the resistance. The second additive will be described later.

[0227] In formula 1-1, R Y11 、R Y121 、R Y122 、R Y123 、RY13 、R Y14 and R Y15 can be independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by Formula 1-a. Specifically, in Formula 1-1, R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 and R Y15 can be independently selected from hydrogen, methyl and a substituent represented by Formula 1-a. In this case, R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 and R Y15 At least one of them may be a substituent represented by Formula 1-a. Specifically, R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 and R Y15 Any one of them may be a substituent represented by Formula 1-a, and the remaining groups except the substituent represented by Formula 1-a may each independently be hydrogen or an alkyl group having 1 to 3 carbon atoms, specifically hydrogen or methyl, more specifically hydrogen.

[0228] In formula 1-2, R Y21 、R Y22 、R Y23 、R Y24 and R Y25 Each of R and R is independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and a substituent represented by Formula 1-a. Y21 、R Y22 、R Y23 、R Y24 and R Y25 can be independently selected from hydrogen, methyl and a substituent represented by Formula 1-a. In this case, R Y21 、R Y22 、R Y23 、R Y24 or R Y25 At least one of them may be a substituent represented by Formula 1-a. Specifically, R Y21 、R Y22 、R Y23 、R Y24 and R Y25Any one of R1to R4in the above formula 1-a can be a substituent represented by formula 1-a, and the rest can each independently be 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 thus does not interfere with the positive film-forming effect of the substituent represented by formula 1-a or the HF scavenging effect of the nitrogen-containing heteroaromatic compound of formula 1-1 and / or formula 1-2.

[0229] [Formula 1-a]

[0230]

[0231] In the above formula 1-a, L1may be selected from a direct bond, an ester, an ether, and an alkylene group having 1 to 5 carbon atoms. Specifically, L1may be a direct bond or an ester. More specifically, L1may be an ester. When L1is an ester (*-C(=0)0-*), the bonding sites of the two bonding sites (*) are not particularly limited, but the bonding site adjacent to oxygen is bonded to R1, and the bonding site adjacent to the carbonyl carbon is bonded to the 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 .

[0232] R1may be a direct bond or an alkylene group having 1 to 5 carbon atoms. Specifically, R1may be a direct bond or an alkylene group having 1 to 3 carbon atoms.

[0233] R2may be *-CH=CH2or *-C≡CH, and specifically can be *-C≡CH.

[0234] The compound represented by formula 1-1 includes at least one selected from the group consisting of compounds represented by the following formula 1-1-A, formula 1-1-B, formula 1-1-C, formula 1-1-D, formula 1-1-E, and formula 1-1-F, and can specifically include a compound represented by formula 1-1-A.

[0235] [Formula 1-1-A]

[0236]

[0237] [Formula 1-1-B]

[0238]

[0239] [Formula 1-1-C]

[0240]

[0241] [Formula 1-1-D]

[0242]

[0243] [Formula 1-1-E]

[0244]

[0245] [Formula 1-1-F]

[0246]

[0247] In Formula 1-1-A, Formula 1-1-B, Formula 1-1-C, Formula 1-1-D, Formula 1-1-E, and Formula 1-1-F, R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 and R Y15 As defined in Formula 1-1.

[0248] The compound represented by Formula 1-2 includes at least one selected from the group consisting of compounds represented by the following Formulas 1-2-A, 1-2-B, 1-2-C, 1-2-D, and 1-2-E.

[0249] [Formula 1-2-A]

[0250]

[0251] [Formula 1-2-B]

[0252]

[0253] [Formula 1-2-C]

[0254]

[0255] [Formula 1-2-D]

[0256]

[0257] [Formula 1-2-E]

[0258]

[0259] In Formula 1-2-A, Formula 1-2-B, Formula 1-2-C, Formula 1-2-D, and Formula 1-2-E, R Y21 、R Y22 、R Y23 、RY24 and R Y25 As defined in Formula 1-2.

[0260] Specifically, the compound represented by Formula 1-1 may include at least one selected from the group consisting of compounds represented by the following Formulas 1-1-A1 to 1-1-A4, and may specifically include the compound represented by the following Formula 1-1-A1.

[0261] [Formula 1-1-A1]

[0262]

[0263] [Formula 1-1-A2]

[0264]

[0265] [Formula 1-1-A3]

[0266]

[0267] [Formula 1-1-A4]

[0268]

[0269] The positive electrode may contain the first additive 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. Within the above range, the capacity ensuring effect due to the inclusion of the positive electrode active material can be fully exhibited, and the positive electrode film-forming effect due to the inclusion of the first additive can be preferably achieved.

[0270] The positive electrode may include a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector. In this case, the positive electrode active material layer may include a positive electrode active material and a first additive.

[0271] The positive electrode current collector is not particularly limited as long as it has conductivity and does not cause chemical changes in the battery. Specifically, the positive electrode current collector may include at least one selected from copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum-cadmium alloy, preferably aluminum.

[0272] The positive electrode current collector may generally have a thickness of 3 μm to 500 μm.

[0273] The positive electrode current collector may have microscopic irregularities formed on its surface to enhance the adhesion 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 body, foam, or non-woven fabric.

[0274] The positive electrode active material layer may be provided on at least one surface of the positive electrode current collector, specifically, may be provided on one surface or both surfaces of the positive electrode current collector.

[0275] The content of the positive electrode active material in the positive electrode active material layer may be 80 wt % to 99 wt %, preferably 92 wt % to 98.5 wt %, in consideration of exhibiting sufficient capacity of the positive electrode active material.

[0276] The positive electrode active material and the first additive have been described above, and thus description thereof will not be repeated.

[0277] In addition to the positive electrode active material and the first additive, the positive electrode active material layer may further include a binder and / or a conductive material.

[0278] The binder is a component that helps to bond the active material to the conductive material and to the current collector, and may specifically include at least one selected from polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber and fluororubber, and may preferably include polyvinylidene fluoride.

[0279] In order to sufficiently ensure the bonding strength between components such as the positive electrode active material, the content of the binder in the positive electrode active material layer may be 1 wt % to 20 wt %, preferably 1.2 wt % to 10 wt %.

[0280] Conductive materials can be used to assist and improve the conductivity of secondary batteries, and there are no particular restrictions, as long as they are conductive and do not cause chemical changes in the battery. Specifically, the positive electrode conductive material can include at least one selected from the following: graphite, such as natural graphite or artificial graphite; carbon black, such as 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 powders; conductive whiskers, such as zinc oxide and potassium titanate; conductive metal oxides, such as titanium oxide; and polyphenylene derivatives. In order to improve conductivity, carbon nanotubes can be preferably included.

[0281] In order to sufficiently ensure conductivity, the content of the conductive material in the positive electrode active material layer may be 1% by weight to 20% by weight, preferably 1.2% by weight to 10% by weight.

[0282] The thickness of the positive electrode active material layer may be 30 μm to 400 μm, preferably 40 μm to 200 μm.

[0283] The positive electrode may be prepared by coating a positive electrode current collector with 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, followed by drying and roll pressing.

[0284] The positive electrode slurry forming solvent may include an organic solvent, such as N-methyl-2-pyrrolidone (NMP).The positive electrode slurry may have a solid content of 40 wt % to 90 wt %, specifically 50 wt % to 80 wt %.

[0285] (2) Negative electrode

[0286] The negative electrode can face the positive electrode.

[0287] The negative electrode contains a negative electrode active material.

[0288] The negative electrode active material is a material capable of inserting / deinserting lithium ions, and may include at least one selected from the group consisting of carbon-based active materials, (semi)metallic active materials and lithium metal, and specifically may include at least one selected from carbon-based active materials and (semi)metallic active materials.

[0289] 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 may preferably include at least one selected from the group consisting of artificial graphite and natural graphite.

[0290] The average particle size (D 50 ) can be 10 μm to 30 μm, preferably 15 μm to 25 μm.

[0291] Specifically, the (semi)metal active material may include: at least one (semi)metal selected from 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 (semi)metal selected from 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 (semi)metal selected from 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); and lithium vanadium oxide.

[0292] More specifically, the (semi)metal-based active material may include a silicon-based active material.

[0293] The silicon-based active material may include silicon (Si), silicon oxide (which may be represented by SiO x (0 <x<2))和硅-碳复合物组成的组中的至少一种。

[0294] In terms of ensuring structural stability during charge and discharge and reducing side reactions with the electrolyte, the average diameter (D 50 ) can be 1 μm to 30 μm, preferably 2 μm to 15 μm.

[0295] The negative electrode may include a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector. In this case, the negative electrode active material may be contained in the negative electrode active material layer.

[0296] The negative electrode current collector is not particularly limited as long as it has conductivity and does not cause chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used as the negative electrode current collector.

[0297] The thickness of the negative electrode current collector may generally be 3 μm to 500 μm.

[0298] The negative electrode current collector may have microscopic irregularities formed on its surface to enhance the adhesion of the negative electrode active material. For example, the negative electrode current collector may be used in various forms such as a film, sheet, foil, mesh, porous body, foam, or non-woven fabric.

[0299] The negative electrode active material layer may be disposed on at least one surface of the negative electrode current collector, specifically, may be disposed on one surface or both surfaces of the negative electrode current collector.

[0300] The content of the negative electrode active material in the negative electrode active material layer may be 60 wt % to 99 wt %, and preferably 75 wt % to 95 wt %.

[0301] The negative electrode active material layer may further include a conductive material and a binder in addition to the negative electrode active material.

[0302] The binder is used to improve the performance of the battery by improving the adhesion between the negative electrode active material layer and the negative electrode current collector, and may include, for example, at least any one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber and materials in which hydrogen is replaced by Li, Na or Ca, and may also include various copolymers thereof.

[0303] The negative active material layer may include the binder in an amount of 0.5 wt % to 10 wt %, preferably 1 wt % to 5 wt %.

[0304] The conductive material is not particularly limited as long as it has conductivity without causing chemical changes in the battery, and, for example, the following conductive materials can be used: graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black; Channel black, furnace black, lamp black and thermal black; conductive fibers, such as carbon fibers or metal fibers; conductive tubes, such as carbon nanotubes; fluorocarbons; metal powders, such as nickel powder; conductive whiskers, such as zinc oxide whiskers and potassium titanate whiskers; conductive metal oxides, such as titanium oxide; or polyphenylene derivatives.

[0305] The negative active material layer may include the conductive material in an amount of 0.5 wt % to 10 wt %, preferably 1 wt % to 5 wt %.

[0306] The negative active material layer may have a thickness of 10 μm to 200 μm, preferably 20 μm to 150 μm.

[0307] The negative electrode may be prepared by coating at least one surface of a negative electrode collector with a negative electrode slurry including a negative electrode active material and / or a binder, a conductive material, and a solvent for forming the negative electrode slurry, followed by drying and roll pressing.

[0308] In terms of promoting dispersion of, for example, the negative electrode active material, binder, and / or conductive material, the solvent for forming the negative electrode slurry may include at least one selected from the group consisting of distilled water, N-methyl-2-pyrrolidone (NMP), ethanol, methanol, and isopropanol, preferably distilled water. The negative electrode slurry may have a solid content of 30% to 80% by weight, specifically 40% to 70% by weight.

[0309] (3) Diaphragm

[0310] The separator may be provided between the positive electrode and the negative electrode.

[0311] As diaphragm, it is possible to use alone or with its laminate using conventional porous polymer film, for example, by polyolefin polymer (such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer) prepared porous polymer film.In addition, common porous non-woven fabrics can be used, such as the non-woven fabric made of high melting point glass fiber or polyethylene terephthalate fiber, but the present invention is not limited thereto. In addition, in order to ensure heat resistance or mechanical strength, it is also possible to use the coated diaphragm comprising ceramic component or polymer component, and it is possible to use the diaphragm with single layer or multilayer structure.

[0312] (4) Non-aqueous electrolytes

[0313] The non-aqueous electrolyte includes a lithium salt, an organic solvent and a second additive.

[0314] 1) Lithium salt

[0315] As the lithium salt used in the present invention, various lithium salts commonly used in non-aqueous electrolytes for lithium secondary batteries can be used without limitation. For example, the lithium salt may include Li + as cations, and may contain a compound selected from the group consisting of 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 - as an anion.

[0316] Specifically, the lithium salt can include at least one selected from the group consisting of 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 can 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).

[0317] The non-aqueous electrolyte can include the lithium salt at a concentration of 0.5 M to 5 M, specifically 0.8 M to 4 M, more specifically 0.8 M to 2.0 M. When the concentration of the lithium salt satisfies the above range, the lithium ion yield (Li + transference number) and the dissociation degree of the lithium ion are improved, and thus, the battery can have improved output characteristics.

[0318] 2) Organic solvent

[0319] The organic solvent is a non-aqueous solvent commonly used in lithium secondary batteries, and is not particularly limited as long as it can minimize decomposition caused by oxidation reaction during the charge and discharge of the secondary battery.

[0320] Specifically, the organic solvent can include at least one selected from the group consisting of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, and a cyclic ester-based organic solvent.

[0321] Specifically, the organic solvent can include a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, or a mixture thereof.

[0322] The cyclic carbonate organic solvent is a high-viscosity organic solvent. Due to its high dielectric constant, it can make the lithium salt in the electrolyte dissociate well, and specifically can 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, and can more specifically include at least one organic solvent selected from the group consisting of ethylene carbonate (EC) and fluoroethylene carbonate (FEC), and further specifically can include ethylene carbonate (EC).

[0323] The straight chain carbonate organic solvent is an organic solvent with low viscosity and low dielectric constant, and specifically can include at least one of the group selected from by dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate and ethyl propyl carbonate, and more specifically can include at least one of the group selected from by ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), and can further specifically include ethyl methyl carbonate (EMC) and diethyl carbonate (DEC).When the straight chain carbonate organic solvent includes ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), the volume ratio of ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) can be 50:50 to 90:10, specifically 80:20 to 90:10, more specifically 85:15 to 90:10.

[0324] The organic solvent can be a mixture of a cyclic carbonate organic solvent and a straight-chain carbonate organic solvent. In this case, the cyclic carbonate organic solvent and the straight-chain carbonate organic solvent can be mixed in a volume ratio of 5:95 to 40:60, specifically 10:90 to 30:70. When the mixing ratio of the cyclic carbonate organic solvent and the straight-chain carbonate organic solvent meets the above range, high dielectric constant and low viscosity can be satisfied simultaneously, and excellent ionic conductivity can be achieved.

[0325] In addition, in order to prepare an electrolyte with high ionic conductivity, the organic solvent may include at least one ester organic solvent selected from a linear ester organic solvent and a cyclic ester organic solvent in addition to at least one carbonate organic solvent selected from a cyclic carbonate organic solvent and a linear carbonate organic solvent.

[0326] The linear ester organic solvent may specifically 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.

[0327] In addition, the cyclic ester-based 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.

[0328] Meanwhile, when necessary, an organic solvent commonly used in non-aqueous electrolytes may be added without limitation. For example, at least one organic solvent selected from ether organic solvents, glyme solvents, and nitrile organic solvents may be further included.

[0329] As the ether solvent, any one selected from 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 thereof may be used, but the embodiment is not limited thereto.

[0330] Glyme solvents are solvents having a high dielectric constant, low surface tension, and low reactivity with metals compared to linear carbonate organic solvents, and may include at least one selected from the group consisting of dimethoxyethane (glyme dimethyl ether, DME), diethoxyethane, diglyme dimethyl ether, triglyme dimethyl ether, and tetraglyme dimethyl ether (TEGDME), but are not limited thereto.

[0331] The nitrile solvent may include at least one selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, octanonitrile, heptanenitrile, cyclopentanenitrile, cyclohexanenitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, benzyl cyanide, 2-fluorophenyl cyanide and 4-fluorophenyl cyanide, etc., but is not limited thereto.

[0332] 4) Additives

[0333] The nonaqueous electrolyte contains a second additive.

[0334] The second additive includes a cyclic sulfur oxide. The cyclic sulfur oxide can form an additional positive electrode film by chemical reaction with the first additive or the positive electrode film derived therefrom. Specifically, the nitrogen-containing heteroaromatic compound in the first additive or the positive electrode film component derived therefrom can form an additional positive electrode film by ring-opening the cyclic sulfur oxide compound, which can improve the high-temperature durability and long-term life performance of the positive electrode. In addition, the compound of formula 1-1 and / or formula 1-2 contained in the first additive contains a compound having sp in the structure. 2 The hybridized orbital nitrogen can, therefore, stably induce reactions with cyclic sulfur oxides.

[0335] In the present invention, in particular, the first additive is contained in the positive electrode and the second additive is contained in the non-aqueous electrolyte, so that the film formation of the positive electrode can be well performed without problems such as unnecessary consumption or increase in negative electrode resistance due to reduction at the negative electrode. For example, if the first additive and the second additive are contained in the non-aqueous electrolyte at the same time, the first additive and the second additive are consumed by the reaction during the reduction of the negative electrode, and therefore, the effect of improving the high-temperature durability of the enhanced film from the positive electrode may not be achieved. In addition, if the first additive and the second additive are contained in the positive electrode, the viscosity of the slurry containing the additives increases during the manufacture of the positive electrode, resulting in poor electrode quality. At the same time, if the second additive is contained in the positive electrode and the first additive is contained in the non-aqueous electrolyte, uneven film formation occurs on the surface of the positive electrode active material due to the side reaction with the Li by-product.

[0336] The cyclic sulfur oxides may contain, for example, propane sultone, propene sultone, ethylene sulfate, ethylene sulfite, and methylene methanedisulfonate in the structure.

[0337] Specifically, the cyclic sulfur oxide may include at least one compound selected from the group consisting of the following formula 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 formula 2-a.

[0338] [Formula 2-a]

[0339]

[0340] In formula 2-a, X 11 and X 12 Each independently is *-O-* or *-C(R X11 )(R X12 )-*, but X 11 and X 12 Not all are *-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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, R 12 and R 13 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl 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 formula 3, or R 12 and R 13together to form a fused ring to provide 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 when R 12 and R 13 When forming an aromatic group having 6 to 20 carbon atoms, R 11 and R 14 does not exist; i is an integer of 1 or 2, and * is a bonding site.

[0341] [Formula 3]

[0342]

[0343] In 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 formula 4, X 61 and X 62 Each independently is *-O-* or *-C(R X61 )(R X62 )-*, but X 11 and X 12 Not all are *-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 alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, R 61 and R 62 is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl 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 Together they form a fused ring to provide 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.

[0344] [Formula 4]

[0345]

[0346] In Formula 4, l is an integer of 1 or 2, and * is a bonding site.

[0347] In the above formula 2-a, X 11 and X 12 Each independently is *-O-* or *-C(R X11 )(R X12 )-*, but X11 and X 12 Not all are *-C(R X11 )(R X12 )-*, for example, X 11 and X 12 Can be *-O-*, or X 11 Can be *-C(R X11 )(R X12 )-* and X 12 It can be *-O-*.

[0348] R 11 、R 14 、R X11 and R X12 Each of them can be independently selected from hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms and a halogen (which can be F, Cl, Br or I), and specifically can be independently selected from hydrogen, methyl, *-CH=CH2, *-C≡CH and fluorine (F).

[0349] R 12 and R 13 They may each independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, and a halogen group, and specifically may each independently be hydrogen, methyl, *-CH=CH2, *-C≡CH, or fluorine (F).

[0350] Or, R 12 and R 13 The fused rings may be formed together to provide 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 forming an aromatic group having 6 to 20 carbon atoms, R 11 and R 14 does not exist. For example, when R 12 and R 13 When together to form a fused ring, they can form a phenyl group, and in this case, R 11 and R 14 It may not exist.

[0351] Or, R 12 and R 13 Each of them can be a substituent represented by Formula 3. In the above Formula 3, L 61 and L 62Each may be independently a direct bond or an alkylene group having 1 to 5 carbon atoms, specifically, each may be independently a direct bond or an alkylene group having 1 to 3 carbon atoms, more specifically, each may be independently a direct bond or a methylene group, even more specifically, each may be independently a methylene group.

[0352] X 61 and X 62 Can be each independently *-O-* or *-C(R X61 )(R X62 )-*, but X 11 and X 12 Not all are *-C(R X61 )(R X62 )-*. For example, X 61 and X 62 Can be *-O-*, or X 61 Can be *-C(R X61 )(R X62 )-*, and X 62 It can be *-O-*.

[0353] R 63 、R X61 and R X62 Each may independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, and specifically, each may independently be hydrogen, a methyl group, *-CH=CH2, *-C≡CH, or fluorine (F).

[0354] R 61 and R 62 They may each independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, and a halogen group, and specifically may each independently be hydrogen, methyl, *-CH=CH2, *-C≡CH, or fluorine (F).

[0355] Or, R 62 and R 63 The fused rings can be formed to provide 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.

[0356] [Formula 2-b]

[0357]

[0358] In formula 2-b, R 21 、R 22 、R 23 and R 24Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen. 21 、R 22 、R 23 and R 24 Each may independently be hydrogen, methyl, *-CH=CH2, *-C≡CH or fluorine (F).

[0359] [Formula 2-c]

[0360]

[0361] In formula 2-c, R 31 、R 32 、R 33 and R 34 Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen. 31 、R 32 、R 33 and R 34 Each may independently be hydrogen, methyl, *-CH=CH2, *-C≡CH or fluorine (F).

[0362] [Formula 2-d]

[0363]

[0364] In formula 2-d, R 41 、R 42 、R 43 and R 46 Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen. 41 、R 42 、R 43 and R 46 Each may independently be hydrogen, methyl, *-CH=CH2, *-C≡CH or fluorine (F).

[0365] R 44 and R 45 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, or R 44 and R 45 together to form a fused ring to provide 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 when R 44and R 45 R 43 and R 46 is absent.

[0366] Specifically, R 44 and R 45 may each independently be hydrogen, methyl, *-CH=CH2, *-C≡CH, or fluorine (F).

[0367] Alternatively, R 44 and R 45 may together form a fused ring to provide 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. In this case, when R 44 and R 45 form an aryl group having 6 to 20 carbon atoms, R 43 and R 46 are absent. For example, when R 44 and R 45 together form a fused ring, they can form a phenyl group, and in this case, R 43 and R 46 may be absent.

[0368] [Formula 2-e]

[0369]

[0370] In Formula 2-e, X 51 and X 52 are each independently *-O-* or *-C(R X51 )(R X52 )-*, but X 51 and X 52 are not both *-C(R X51 )(R X52 )-*, R 51 , R 52 , R 53 , R 54 , R 55 , and R 56 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or halogen, and j is an integer of 1 or 2.

[0371] For example, X 51 and X 52 may each be *-O-*, or X 51 may be *-C(R X51 )(R X52 )-*, and X52 It can be *-O-*.

[0372] In addition, R 51 、R 52 、R 53 、R 54 、R 55 and R 56 Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen. 51 、R 52 、R 53 、R 54 、R 55 and R 56 Each may independently be hydrogen, methyl, *-CH=CH2, *-C≡CH or fluorine (F).

[0373] [Formula 2-f]

[0374]

[0375] In formula 2-f, X 71 and X 72 Each independently is *-O-* or *-C(R X71 )(R X72 )-*, but X 71 and X 72 Not all are *-C(R X71 )(R X72 )-*,X 73 and X 74 Each independently is *-O-* or *-C(R X73 )(R X74 )-*, but X 73 and X 74 Not all are *-C(R X73 )(R X74 )-*,R X71 、R X72 、R X73 and R X74 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, m and n are each independently an integer of 1 or 2, and * is a bonding site.

[0376] For example, X 71 and X 72 Can be *-O-*, or X 71 Can be *-C(R X71 )(R X72 )-*, and X 72It can be *-O-*. In addition, for example, X 73 and X 74 Can be *-O-*, or X 73 Can be *-C(R X73 )(R X73 )-*, and X 74 It can be *-O-*.

[0377] In addition, R X71 、R X72 、R X73 and R X74 Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen. X71 、R X72 、R X73 and R X74 Each may independently be hydrogen, methyl, *-CH=CH2, *-C≡CH or fluorine (F).

[0378] [Formula 2-g]

[0379]

[0380] In formula 2-g, R 81 、R 82 、R 83 and R 84 and R are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen. 81 、R 82 、R 83 and R 84 Each may independently be hydrogen, methyl, *-CH=CH2, *-C≡CH or fluorine (F).

[0381] Specifically, the cyclic sulfur oxide can include at least one selected from the group consisting of compounds represented by Formula 2-a-1 to 2-a-25, Formula 2-b-1, Formula 2-c-1, Formula 2-d-1, Formula 2-e-1, Formula 2-e-2, Formula 2-f-1, and Formula 2-g-1. For example, the compound represented by Formula 2-a can include at least one selected from the group consisting of compounds represented by Formula 2-a-1 to 2-a-25. Also, the compound represented by Formula 2-b can include the compound represented by Formula 2-b-1. Also, the compound represented by Formula 2-c can include the compound represented by Formula 2-c-1. Also, the compound represented by Formula 2-d can include the compound represented by Formula 2-d-1. Also, the compound represented by Formula 2-e can include at least one selected from the group consisting of compounds represented by Formula 2-e-1 and Formula 2-e-2. Also, the compound represented by Formula 2-f can include the compound represented by Formula 2-f-1.

[0382] More specifically, the cyclic sulfur oxide can include at least one selected from the group consisting of compounds represented by Formula 2-a-1 to 2-a-10, Formula 2-b-1, Formula 2-c-1, Formula 2-d-1, Formula 2-e-1, Formula 2-e-2, and Formula 2-f-1.

[0383] More specifically, the cyclic sulfur oxide can include at least one selected from the group consisting of compounds represented by Formula 2-a-1, Formula 2-a-2, Formula 2-a-3, Formula 2-a-4, Formula 2-a-6, Formula 2-a-10, and Formula 2-b-1. More specifically, the cyclic sulfur oxide can include at least one selected from the group consisting of compounds represented by Formula 2-a-1, Formula 2-a-4, Formula 2-a-10, and Formula 2-b-1. More specifically, the cyclic sulfur oxide can include at least one selected from the group consisting of compounds represented by Formula 2-a-1, Formula 2-a-10, and Formula 2-b-1. More specifically, the cyclic sulfur oxide can include the compound represented by Formula 2-a-10.

[0384] [Formula 2-a-1]

[0385]

[0386] [Formula 2-a-2]

[0387]

[0388] [Formula 2-a-3]

[0389]

[0390] [Formula 2-a-4]

[0391]

[0392] [Formula 2-a-5]

[0393]

[0394] [Formula 2-a-6]

[0395]

[0396] [Formula 2-a-7]

[0397]

[0398] [Formula 2-a-8]

[0399]

[0400] [Formula 2-a-9]

[0401]

[0402] [Formula 2-a-10]

[0403]

[0404] [Formula 2-a-11]

[0405]

[0406] [Formula 2-a-12]

[0407]

[0408] [Formula 2-a-13]

[0409]

[0410] [Formula 2-a-14]

[0411]

[0412] [Formula 2-a-15]

[0413]

[0414] [Formula 2-a-16]

[0415]

[0416] [Formula 2-a-17]

[0417]

[0418] [Formula 2-a-18]

[0419]

[0420] [Formula 2-a-19]

[0421]

[0422] [Formula 2-a-20]

[0423]

[0424] [Formula 2-a-21]

[0425]

[0426] [Formula 2-a-22]

[0427]

[0428] [Formula 2-a-23]

[0429]

[0430] [Formula 2-a-24]

[0431]

[0432] [Formula 2-a-25]

[0433]

[0434] [Formula 2-b-1]

[0435]

[0436] [Formula 2-c-1]

[0437]

[0438] [Formula 2-d-1]

[0439]

[0440] [Formula 2-e-1]

[0441]

[0442] [Formula 2-e-2]

[0443]

[0444] [Formula 2-f-1]

[0445]

[0446] [Formula 2-g-1]

[0447]

[0448] The non-aqueous electrolyte may include the second additive in an amount of 0.01 to 10 wt %, specifically 0.05 to 7 wt %, more specifically 0.1 to 2 wt %, and more specifically 0.5 to 1.5 wt %. When the second additive is used within the above range, the effect of capturing active oxygen generated during initial activation can be sufficiently provided, and concerns about increased resistance when excessively added can be prevented.

[0449] The weight ratio of the first additive contained in the positive electrode to the weight ratio of the second additive contained in the non-aqueous electrolyte can 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, and within the above-mentioned weight ratio range, the effects produced by the combined use of the first additive and the second additive are in a good balance, and therefore, it can preferably provide the effect of improving the high-temperature service life performance, high-temperature storage performance and safety of the lithium secondary battery.

[0450] In addition to the first additive and the second additive, the additive may further include an additional additive (which may be expressed as a third additive). The additional additive may be included in the non-aqueous electrolyte to prevent negative electrode collapse caused by decomposition of the non-aqueous electrolyte in a high power environment, provide low-temperature high-rate discharge characteristics, high-temperature stability and overcharge protection, and suppress battery expansion at high temperatures.

[0451] Specifically, the additional additive may include at least one selected from vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, succinonitrile, adiponitrile, ethylene sulfate, lithium bis(oxalato)borate (LiBOB), 3-trimethoxysilyl-propyl-N-aniline (TMSPa) and tris(trimethylsilyl)phosphite (TMSPi), and specifically may be vinylene carbonate.

[0452] The non-aqueous electrolyte may include additional additives in an amount of 0.1 wt % to 15 wt %.

[0453] The outer shape of the lithium secondary battery of the present invention is not particularly limited, and thus a cylindrical shape using a can, a prismatic shape, a pouch shape, or a coin shape may be used.

[0454] Hereinafter, the present invention will be described in more detail by specific embodiments. However, the embodiments shown below are only shown for understanding the present invention, and the scope of the inventive concept is not limited thereto. It is obvious to those skilled in the art that various modifications and changes can be made within the scope of the present invention and within the technical scope, and these modifications and changes fall within the scope of the claims included herein.

[0455] Examples and Comparative Examples

[0456] Example 1

[0457] (Preparation of non-aqueous electrolyte)

[0458] As the organic solvent, a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 20:70:10 was used.

[0459] LiPF 6 as a lithium salt and a compound represented by Formula 2-a-1 as a second additive are added to an organic solvent to prepare a non-aqueous electrolyte.

[0460] LiPF6 is contained in the non-aqueous electrolyte at a molar concentration of 1.2M.

[0461] The compound represented by Formula 2-a-1 was contained in the non-aqueous electrolyte in an amount of 1% by weight.

[0462] (Manufacturing of lithium secondary batteries)

[0463] The positive electrode active material (Li[Ni 0.6 Co 0.1 Mn 0.3 ]O2), a first additive (a compound represented by Formula 1-1-A1), a conductive material (carbon nanotubes), and a binder (polyvinylidene fluoride) were added to N-methyl-2-pyrrolidone (NMP) as a solvent 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 surface of a positive electrode current collector (Al film) having a thickness of 12 μm, and then dried and roll-pressed to form a positive electrode active material layer (thickness: 115 μm), which was used as a positive electrode.

[0464] The negative electrode active material (graphite and silicon-carbon composite material mixed at a weight ratio of 95:5), the conductive material (graphite and silicon-carbon composite material mixed at a weight ratio of 95:5), and the binder (styrene-butadiene rubber and carboxymethyl cellulose) were added to distilled water as a solvent at a weight ratio of 94.9:0.5:4.6 to prepare a negative electrode slurry (solid content: 54 wt%). The negative electrode slurry was applied to one surface of a negative electrode current collector (Cu film) with a thickness of 6 μm, then dried and roll-pressed to form a negative electrode active material layer (thickness: 160 μm), which was used as the negative electrode.

[0465] A polyethylene porous film separator was placed between the prepared positive electrode and negative electrode in a dry room, and then the prepared nonaqueous electrolyte was injected to prepare a lithium secondary battery.

[0466] Example 2

[0467] A nonaqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 2-a-4 was included as a second additive in the nonaqueous electrolyte instead of the compound represented by Formula 2-a-1.

[0468] Example 3

[0469] A nonaqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 2-b-1 was included in the nonaqueous electrolyte as a second additive instead of the compound represented by Formula 2-a-1.

[0470] Example 4

[0471] A nonaqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 2-a-10 was included in the nonaqueous electrolyte as a second additive instead of the compound represented by Formula 2-a-1.

[0472] Example 5

[0473] A nonaqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 2-a-2 was included as a second additive in the nonaqueous electrolyte instead of the compound represented by Formula 2-a-1.

[0474] Example 6

[0475] A nonaqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 2-a-3 was included in the nonaqueous electrolyte as a second additive instead of the compound represented by Formula 2-a-1.

[0476] Example 7

[0477] A nonaqueous electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 2-a-6 was included in the nonaqueous electrolyte as a second additive instead of the compound represented by Formula 2-a-1.

[0478] Comparative Example 1

[0479] (Preparation of non-aqueous electrolyte)

[0480] A non-aqueous electrolyte was prepared in the same manner as in Example 1, except that the second additive (the compound represented by Formula 2-a-1) was not added to the non-aqueous electrolyte.

[0481] (Manufacturing of lithium secondary batteries)

[0482] The positive electrode 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 N-methyl-2-pyrrolidone (NMP) as a solvent 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 surface of a positive electrode current collector (Al film) with a thickness of 12 μm, then dried and roll-pressed to form a positive electrode active material layer (thickness: 115 μm), which was used as the positive electrode.

[0483] A lithium secondary battery was prepared in the same manner as in Example 1 except that the nonaqueous electrolyte and positive electrode prepared above were used.

[0484] Comparative Example 2

[0485] (Preparation of non-aqueous electrolyte)

[0486] A nonaqueous electrolyte was prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 1-1-A1 was included in the nonaqueous electrolyte instead of the second additive (the compound represented by Formula 2-a-1).

[0487] (Manufacturing of lithium secondary batteries)

[0488] A positive electrode was prepared in the same manner as in Comparative Example 1.

[0489] A lithium secondary battery was prepared in the same manner as in Example 1 except that the nonaqueous electrolyte and positive electrode prepared above were used.

[0490] Comparative Example 3

[0491] (Preparation of non-aqueous electrolyte)

[0492] In the same manner as in Example 1, a non-aqueous electrolyte was prepared.

[0493] (Manufacturing of lithium secondary batteries)

[0494] A positive electrode was prepared in the same manner as in Comparative Example 1.

[0495] A lithium secondary battery was prepared in the same manner as in Example 1 except that the nonaqueous electrolyte and positive electrode prepared above were used.

[0496] Comparative Example 4

[0497] (Preparation of non-aqueous electrolyte)

[0498] A non-aqueous electrolyte was prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 1-1-A1 was further included in the non-aqueous electrolyte.

[0499] (Manufacturing of lithium secondary batteries)

[0500] A positive electrode was prepared in the same manner as in Comparative Example 1.

[0501] A lithium secondary battery was prepared in the same manner as in Example 1 except that the nonaqueous electrolyte and positive electrode prepared above were used.

[0502] Comparative Example 5

[0503] (Preparation of non-aqueous electrolyte)

[0504] In the same manner as in Comparative Example 1, a nonaqueous electrolyte was prepared.

[0505] (Manufacturing of lithium secondary batteries)

[0506] A lithium secondary battery was prepared in the same manner as in Example 1, except that the nonaqueous electrolyte prepared above was used.

[0507] Comparative Example 6

[0508] (Preparation of non-aqueous electrolyte)

[0509] In the same manner as in Comparative Example 2, a nonaqueous electrolyte was prepared.

[0510] (Manufacturing of lithium secondary batteries)

[0511] The positive electrode 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 N-methyl-2-pyrrolidone (NMP) as a solvent at 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 surface of a positive electrode current collector (Al film) having a thickness of 12 μm, and then dried and roll-pressed to form a positive electrode active material layer (thickness: 115 μm), which was used as a positive electrode.

[0512] A lithium secondary battery was prepared in the same manner as in Example 1 except that the nonaqueous electrolyte and positive electrode prepared above were used.

[0513] Experimental example

[0514] Experimental Example 1: Evaluation of High-Temperature Cycling Performance

[0515] The lithium secondary batteries of Examples 1 to 7 and Comparative Examples 1 to 6 prepared above were charged to 4.35 V (1 / 40 C) at 45°C under CC / CV and 0.33 C, discharged to 2.0 V under CC and 0.33 C, thereby as one cycle, and 300 charge and discharge cycles were performed using an electrochemical charge-discharge apparatus.

[0516] (1) Capacity retention rate

[0517] The capacity retention rate was calculated by the following equation, and the results are shown in Table 1 below.

[0518] Capacity retention rate (%) = {(discharge capacity after the 300th cycle) / (discharge capacity after the 1st cycle)} x 100

[0519] (2) Resistance increase rate

[0520] After one charge and discharge cycle, the discharge capacity after one cycle was measured using an electrochemical charge-discharge apparatus, the state of charge (SOC) was adjusted to 50%, and then a pulse of 2.5 C was applied for 10 seconds to calculate the initial resistance by the difference between the voltage before the pulse application and the voltage after the pulse application.

[0521] After 300 cycles of charge and discharge, the resistance after 300 cycles was calculated in the same manner as described above, the resistance increase rate was calculated using the following equation, and the results are shown in Table 1 below.

[0522] Resistance increase rate (%) = (resistance after the 300th cycle - initial resistance) / initial resistance x 100

[0523] (3) Gas generation amount

[0524] After 300 cycles of charge and discharge, the amount of gas generated from the lithium secondary battery was measured using GC-FID / TCD, and the results are shown in Table 1 below.

[0525] [Table 1]

[0526]

[0527] Referring to Table 1, it was determined that the lithium secondary batteries of Examples 1 to 7, in which the positive electrode containing the first additive and the non-aqueous electrolyte containing the second additive were combined, had a higher capacity retention rate, a lower resistance increase rate, and less gas generation during high-temperature cycle charge / discharge, compared to the lithium secondary batteries of Comparative Examples 1 to 6.

[0528] Experimental Example 2: Evaluation of high-temperature storage performance

[0529] The lithium secondary batteries of Examples 1 to 7 and Comparative Examples 1 to 6 prepared above were charged to 4.35 V (1 / 40C) under CC / CV and 0.33C at 25°C and discharged to 2.0 V under 0.33C for initial charge / discharge, and then charged to 4.35 V (1 / 40C) under CC / CV and 0.33C at 25°C, and then stored at 60°C for 12 weeks.

[0530] (1) Capacity retention rate

[0531] After storage for 12 weeks, the lithium secondary battery was charged to 4.35 V (1 / 40 C) under CC / CV and 0.33 C conditions at 25° C. and discharged to 2.0 V under 0.33 C conditions to measure the capacity during discharge.

[0532] The capacity retention rate was evaluated according to the following formula, and the results are shown in Table 2 below.

[0533] Capacity retention (%) = (discharge capacity after 12 weeks of storage / initial discharge capacity) × 100

[0534] (2) Resistance increase rate

[0535] After the initial charge / discharge, the capacity was measured at room temperature. The lithium secondary battery was charged to an SOC of 50% relative to the discharge capacity, discharged at a current of 2.5C for 10 seconds, and the resistance was measured using the voltage drop difference at this time as the initial resistance. The battery was then stored at 60°C for 12 weeks. The final resistance was measured in the same manner as the initial resistance, and the resistance increase rate was calculated using the following equation. The results are shown in Table 2 below.

[0536] Resistance increase rate (%) = (final resistance - initial resistance) / (initial resistance) × 100

[0537] (3) Gas generation

[0538] After storage for 12 weeks, the amount of gas generated from the lithium secondary battery was measured using GC-FID / TCD, and the results are shown in Table 2 below.

[0539] [Table 2]

[0540]

[0541] Referring to Table 2, it was determined that the lithium secondary batteries of Examples 1 to 7 (in which a positive electrode containing a first additive and a non-aqueous electrolyte containing a second additive are combined) had higher capacity retention, lower resistance increase rate, and less gas generation during high-temperature storage than the lithium secondary batteries of Comparative Examples 1 to 6.

Claims

1. A lithium secondary battery comprising: positive electrode; negative electrode; a separator disposed between the positive electrode and the negative electrode; and non-aqueous electrolytes, 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 includes at least one selected from the group consisting of compounds represented by the following Formula 1-1 and Formula 1-2, and The second additive comprises a cyclic sulfur oxide compound, [Formula 1-1] In formula 1-1, Y 11 Nitrogen (N) or R Y11 Substituted carbon (C), Y 12 For oxygen (O), sulfur (S), R Y121 Substituted nitrogen (N), or R Y122 and R Y123 Substituted carbon (C), Y 13 Nitrogen (N) or R Y13 Substituted carbon (C), Y 14 Nitrogen (N) or R Y14 substituted carbon (C), and Y 15 Nitrogen (N) or R Y15 Substituted carbon (C), wherein Y 11 and Y 15 At least one of is nitrogen (N), and Y 11 、Y 12 、Y 13 、Y 14 or Y 15 At least one of is carbon (C), and R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 and R Y15 Each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms and a substituent represented by the following formula 1-a, wherein R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 or R Y15 At least one of them is a substituent represented by formula 1-a, [Formula 1-2] In formula 1-2, Y 21 Nitrogen (N) or R Y21 Substituted carbon (C), Y 22 Nitrogen (N) or R Y22 Substituted carbon (C), Y 23 Nitrogen (N) or R Y23 Substituted carbon (C), Y 24 Nitrogen (N) or R Y24 substituted carbon (C), and Y 25 Nitrogen (N) or R Y25 Substituted carbon (C), wherein Y 21 、Y 22 、Y 23 、Y 24 or Y 25 At least one of is carbon (C), and R Y21 、R Y22 、R Y23 、R Y24 and R Y25 Each independently selected from hydrogen, an alkyl group having 1 to 3 carbon atoms and a substituent represented by the following formula 1-a, wherein R Y21 、R Y22 、R Y23 、R Y24 or R Y25 At least one of them is a substituent represented by formula 1-a, and [Formula 1-a] Wherein, in 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.

2. The lithium secondary battery according to claim 1, wherein The compound represented by the above formula 1-1 includes at least one selected from the group consisting of compounds represented by the following formulas 1-1-A, 1-1-B, 1-1-C, 1-1-D, 1-1-E, and 1-1-F: [Formula 1-1-A] [Formula 1-1-B] [Formula 1-1-C] [Formula 1-1-D] [Formula 1-1-E] [Formula 1-1-F] In Formula 1-1-A, Formula 1-1-B, Formula 1-1-C, Formula 1-1-D, Formula 1-1-E, and Formula 1-1-F, R Y11 、R Y121 、R Y122 、R Y123 、R Y13 、R Y14 and R Y15 As defined in Formula 1-1.

3. The lithium secondary battery according to claim 1, wherein The compound represented by the above formula 1-2 includes at least one selected from the group consisting of compounds represented by the following formulas 1-2-A, 1-2-B, 1-2-C, 1-2-D, and 1-2-E: [Formula 1-2-A] [Formula 1-2-B] [Formula 1-2-C] [Formula 1-2-D] [Formula 1-2-E] In Formula 1-2-A, Formula 1-2-B, Formula 1-2-C, Formula 1-2-D, and Formula 1-2-E, R Y21 、R Y22 、R Y23 、R Y24 and R Y25 As defined in Formula 1-2.

4. The lithium secondary battery according to claim 1, wherein The first additive includes a compound represented by Formula 1-1.

5. The lithium secondary battery according to claim 1, wherein The compound represented by Formula 1-1 includes at least one selected from the group consisting of compounds represented by the following Formulas 1-1-A1 to 1-1-A4: [Formula 1-1-A1] [Formula 1-1-A2] [Formula 1-1-A3] [Formula 1-1-A4] 6. The lithium secondary battery according to claim 1, wherein The positive electrode includes the first additive in an amount of 0.004 parts by weight to 8 parts by weight relative to 100 parts by weight of the positive electrode active material.

7. The lithium secondary battery according to claim 1, wherein The positive electrode includes the first additive in an amount of 0.04 parts by weight to 4 parts by weight relative to 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 selected from the group consisting of compounds represented by the following formula 2-a, formula 2-b, formula 2-c, formula 2-d, formula 2-e, formula 2-f and formula 2-g: [Formula 2-a] Wherein, in formula 2-a, X 11 and X 12 Each independently is *-O-* or *-C(R X11 )(R X12 )-*, but X 11 and X 12 Not all are *-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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, R 12 and R 13 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl 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 formula 3, or R 12 and R 13 together to form a fused ring to provide 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 when R 12 and R 13 When forming an aromatic group having 6 to 20 carbon atoms, R 11 and R 14 does not exist, i is an integer of 1 or 2, and * is the bonding site, [Formula 2-b] Among them, in 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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, [Formula 2-c] Among them, in 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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, [Formula 2-d] Among them, in 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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, and R 44 and R 45 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, or R 44 and R 45 together to form a fused ring to provide 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 when R 44 and R 45 When forming an aromatic group having 6 to 20 carbon atoms, R 43 and R 46 does not exist, [Formula 2-e] Among them, in formula 2-e, X 51 and X 52 Each independently is *-O-* or *-C(R X51 )(R X52 )-*, but X 51 and X 52 Not all are *-C(R X51 )(R X52 )-*, R 51 、R 52 、R 53 、R 54 、R 55 and R 56 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, and j is an integer of 1 or 2, [Formula 2-f] Among them, in formula 2-f, X 71 and X 72 Each independently is *-O-* or *-C(R X71 )(R X72 )-*, but X 71 and X 72 Not all are *-C(R X71 )(R X72 )-*, X 73 and X 74 Each independently is *-O-* or *-C(R X73 )(R X74 )-*, but X 73 and X 74 Not all are *-C(R X73 )(R X74 )-*, R X71 、R X72 、R X73 and R X74 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, m and n are each independently an integer of 1 or 2, and * is the bonding site, [Formula 2-g] Among them, in 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, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, [Formula 3] In 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 formula 4, X 61 and X 62 Each independently is *-O-* or *-C(R X61 )(R X62 )-*, but X 11 and X 12 Not all are *-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 alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, or a halogen, R 61 and R 62 is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl 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 together to form a fused ring to provide 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 the bonding site, [Formula 4] Wherein, in Formula 4, l is an integer of 1 or 2, and * is a bonding site.

9. The lithium secondary battery according to claim 1, wherein The cyclic sulfur oxide compound includes at least one selected from the group consisting of compounds represented by the following 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: [Formula 2-a-1] [Formula 2-a-2] [Formula 2-a-3] [Formula 2-a-4] [Formula 2-a-5] [Formula 2-a-6] [Formula 2-a-7] [Formula 2-a-8] [Formula 2-a-9] [Formula 2-a-10] [Formula 2-a-11] [Formula 2-a-12] [Formula 2-a-13] [Formula 2-a-14] [Formula 2-a-15] [Formula 2-a-16] [Formula 2-a-17] [Formula 2-a-18] [Formula 2-a-19] [Formula 2-a-20] [Formula 2-a-21] [Formula 2-a-22] [Formula 2-a-23] [Formula 2-a-24] [Formula 2-a-25] [Formula 2-b-1] [Formula 2-c-1] [Formula 2-d-1] [Formula 2-e-1] [Formula 2-e-2] [Formula 2-f-1] [Formula 2-g-1] 10. The lithium secondary battery according to claim 1, wherein The nonaqueous electrolyte includes the second additive in an amount of 0.01 wt % to 10 wt %.

11. The lithium secondary battery according to claim 1, wherein The positive electrode active material includes a lithium composite transition metal oxide represented by the following formula A: [Formula A] Li 1+x [Ni a Co b Mr c M 1 d ]O 2+w Wherein, in the above 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 It is at least one 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 lithium secondary battery according to claim 1, wherein The negative electrode includes a negative electrode active material, and the negative electrode active material contains at least one selected from the group consisting of a carbon-based active material and a silicon-based active material.

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