Lithium secondary battery

Abstract

The present invention provides a battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein the positive electrode comprises a positive electrode active material, the positive electrode active material comprising a lithium transition metal oxide represented by a specific chemical formula, the non-aqueous electrolyte comprising a lithium salt, an organic solvent, and an additive, the additive comprising a first additive and a second additive, the first additive comprising a phosphate-based additive including a silyl group, and the second additive comprising a compound represented by a specific chemical formula.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0046337 filed on April 7, 2023, and Korean Patent Application No. 10-2023-0183780 filed on December 15, 2023, and all contents disclosed in the documents of the relevant Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a lithium secondary battery. [Background technology]

[0003] In recent years, the application areas of lithium secondary batteries have rapidly expanded from power supply for electronic devices such as electrical, electronic, communication, and computer equipment to power storage and supply for large-area devices such as automobiles and power storage devices. Accordingly, there has been an increasing demand for high-capacity, high-power, and highly stable secondary batteries.

[0004] The lithium secondary battery typically comprises a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, an electrolyte serving as a medium for transferring lithium ions, and a separator. The negative electrode active material may be a carbon-based active material or a silicone-based active material. The positive electrode active material may be a lithium transition metal oxide such as lithium cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), or a lithium nickel-cobalt-manganese composite transition metal oxide.

[0005] On the other hand, in order to construct a high-capacity secondary battery, improvements have been made to the properties of each of the positive electrode, negative electrode, electrolyte, and separator. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a lithium secondary battery using a lithium transition metal oxide as a positive electrode active material, in which the nickel content is reduced to a specific level, and which has improved life performance and storage performance when driven at a high voltage. [Means for solving the problem]

[0007] One embodiment of 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, wherein the positive electrode includes a positive electrode active material, the positive electrode active material including a lithium transition metal oxide represented by the following chemical formula X, the non-aqueous electrolyte includes a lithium salt, an organic solvent, and an additive, the additive including a first additive and a second additive, the first additive including a phosphate-based additive including a silyl group, and the second additive including a compound represented by the following chemical formula 1:

[0008] [Chemical formula X] Li 1+x [Ni a Co b Mn c M 1 d ]O 2+w

[0009] In the chemical formula X, 0≦x≦0.5, a+b+c+d=1, 0.5≦a≦0.7, 0≦b≦0.15, c=1−abd, 0≦d≦0.1, 0≦b / a≦0.2, 1≦a / c≦3, and 0≦w≦1; M 1 is one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo.

[0010] [Chemical formula 1] [ka]

[0011] In the above chemical formula 1, n is 1 or 2, L1 and L2 each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, and R1 and R2 each independently represent a substituent represented by the following chemical formula 2: [Chemical formula 2] [ka] In the above Chemical Formula 2, m is 1 or 2, and X1 and X2 each independently represent -O- or -C(R 31 )(R 32 )-, wherein at least one of X1 and X2 is -O-, and R 31 ~R 36 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -C(=O)-R4, or -R5-OC(=O)-R6, and R4 and R6 are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, R5 is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, and L1, L The substituents of R2, R4, R5, and R6 are each independently one or more selected from the group consisting of deuterium, -F, -Cl, -Br, -I, -CN, -NO2, and -SO3, and * indicates the position of bonding to L1 or L2. When both L1 and L2 are direct bonds, R1 and R2 are not simultaneously CS-7 below; when both L1 and L2 are methylene groups and n is 2, R1 and R2 are not simultaneously CS-2 below. [ka] [Effects of the Invention]

[0012] A lithium secondary battery according to one embodiment of the present invention is characterized by using a lithium transition metal oxide containing nickel, cobalt, and manganese adjusted within a specific range as a positive electrode active material, and including a first additive (e.g., containing tris(trimethylsilyl)phosphate) and a second additive (containing a cyclic sulfur oxide represented by a specific chemical formula) as additives for a non-aqueous electrolyte. According to one embodiment of the present invention, the organic action of the first additive and the second additive reduces resistance and forms a highly durable coating on the positive electrode, which is particularly advantageous because it can improve the life and storage performance of lithium secondary batteries that are required to be used at high voltages, while also reducing resistance. DETAILED DESCRIPTION OF THE INVENTION

[0013] The terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0014] As used herein, the terms "comprises," "comprises," or "having" are intended to specify the presence of embodied features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the presence or possible addition of one or more other features, numbers, steps, components, or combinations thereof.

[0015] On the other hand, unless otherwise specified in this specification, "*" means a linking moiety (bonding site) between the ends of the same or different atoms or chemical formulae.

[0016] Furthermore, in the description of "number of carbon atoms a to b" herein, "a" and "b" refer to the number of carbon atoms contained in a specific functional group. That is, the functional group may contain "a" to "b" carbon atoms. For example, "an alkyl group having 1 to 5 carbon atoms" refers to an alkyl group containing 1 to 5 carbon atoms, i.e., CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, (CH3)2CHCH2-, CH3CH2CH2CH2CH2-, (CH3)2CHCH2CH2-, CH3)2CHCH2CH2-, (CH3)2CHCH2CH2-, etc.

[0017] In this specification, both the alkyl group and the aryl group may be substituted or unsubstituted. Unless otherwise defined, the term "substituted" means that at least one hydrogen atom bonded to a carbon atom is replaced with an element other than hydrogen, such as an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, a cycloalkynyl group having 3 to 12 carbon atoms, a heterocycloalkyl group having 3 to 12 carbon atoms, a heterocycloalkenyl group having 3 to 12 carbon atoms, a heterocycloalkynyl group having 2 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, a halogen atom, a fluoroalkyl group having 1 to 20 carbon atoms, a nitro group, an aryl group having 6 to 20 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, or a haloaryl group having 6 to 20 carbon atoms.

[0018] As used in this specification, the terms "about," "approximately," and "substantially" are used to mean a numerical value, a range of degree, or a value close to that range, taking into account inherent manufacturing and material tolerances, and are used to prevent infringers from unfairly taking advantage of the disclosure content in which exact or absolute numerical values ​​provided for understanding the present invention are mentioned.

[0019] To increase the energy density of the positive electrode of lithium secondary batteries, lithium nickel-cobalt-manganese composite transition metal oxides, which contain 80 mol% or more of nickel relative to the transition metal, have been studied. However, increasing the nickel content of lithium nickel-cobalt-manganese composite transition metal oxides can lead to a decrease in the thermal stability of the positive electrode.

[0020] To prevent this problem, if the nickel content in the lithium nickel-cobalt-manganese composite transition metal oxide is reduced, the driving voltage must be increased to achieve the required energy density. The present invention provides a lithium secondary battery that uses a lithium transition metal oxide containing nickel, cobalt, and manganese within a specific range as a positive electrode active material and includes a specific additive in the non-aqueous electrolyte, thereby reducing electrolyte side reactions at the positive electrode even when driven at such high voltages.

[0021] The present invention will now be described in more detail.

[0022] Lithium secondary battery The present invention relates to a lithium secondary battery.

[0023] A lithium secondary battery according to one embodiment of the present invention includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte. The positive electrode includes a positive electrode active material, and the positive electrode active material includes a lithium transition metal oxide represented by the following chemical formula X. The non-aqueous electrolyte includes a lithium salt, an organic solvent, and an additive. The additive includes a first additive and a second additive. The first additive includes a phosphate-based additive including a silyl group, for example, tris(trimethylsilyl)phosphate, and the second additive includes a compound represented by the following chemical formula 1.

[0024] [Chemical formula X] Li 1+x [Ni a Co b Mn c M 1d ]O 2+w

[0025] In the chemical formula X, 0≦x≦0.5, a+b+c+d=1, 0.5≦a≦0.7, 0≦b≦0.15, c=1−abd, 0≦d≦0.1, 0≦b / a≦0.2, 1≦a / c≦3, and 0≦w≦1; M 1 is one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo.

[0026] [Chemical formula 1] [ka]

[0027] In the above chemical formula 1, n is 1 or 2, L1 and L2 each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, and R1 and R2 each independently represent a substituent represented by the following chemical formula 2: [Chemical formula 2] [ka] In the above Chemical Formula 2, m is 1 or 2, and X1 and X2 each independently represent -O- or -C(R 31 )(R 32 )-, wherein at least one of X1 and X2 is -O-, and R 31 ~R 36are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -C(=O)-R4, or -R5-OC(=O)-R6, and R4 and R6 are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, R5 is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, and L1, L The substituents of R2, R4, R5, and R6 are each independently one or more selected from the group consisting of deuterium, -F, -Cl, -Br, -I, -CN, -NO2, and -SO3, and * indicates the position of bonding to L1 or L2. When both L1 and L2 are direct bonds, R1 and R2 are not simultaneously CS-7 below; when both L1 and L2 are methylene groups and n is 2, R1 and R2 are not simultaneously CS-2 below. [ka]

[0028] The lithium secondary battery includes a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. For example, the lithium secondary battery includes a positive electrode, a negative electrode facing the positive electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte. The lithium secondary battery can be manufactured by placing an electrode assembly including the positive electrode, the negative electrode facing the positive electrode, and a separator interposed between the positive electrode and the negative electrode in a battery case and then injecting the non-aqueous electrolyte.

[0029] (1) Positive electrode The positive electrode includes a positive electrode active material.

[0030] According to one embodiment, the positive electrode active material includes a lithium transition metal oxide represented by the following chemical formula X:

[0031] [Chemical formula X] Li 1+x [Ni a Co b Mn c M 1d ]O 2+w

[0032] In the chemical formula X, 0≦x≦0.5, a+b+c+d=1, 0.5≦a≦0.7, 0≦b≦0.15, c=1−abd, 0≦d≦0.1, 0≦b / a≦0.2, 1≦a / c≦3, and 0≦w≦1; M 1 is one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo.

[0033] The lithium transition metal oxide represented by the chemical formula X is distinguished from high-nickel lithium transition metal oxides, for example, in which the Ni content exceeds 70 mol % based on the metals excluding lithium. The high-nickel lithium transition metal oxides contain a large amount of nickel, which causes problems with reduced thermal stability. In particular, at high voltages, the lattice structure changes, causing degradation to a rock salt form, which reduces lithium mobility and leads to performance degradation, which is undesirable.

[0034] Meanwhile, the compound represented by the chemical formula X has a relatively low nickel content compared to high-nickel lithium transition metal oxides, and therefore needs to be driven at a high voltage (e.g., 4.35 V or higher) to increase the energy density of the positive electrode. However, when driven at such a high voltage, for example, oxygen is released due to a change in the oxidation number of nickel and cobalt, which intensifies electrolyte side reactions, resulting in problems such as reduced lifespan and storage performance.

[0035] A lithium secondary battery according to one embodiment of the present invention uses a lithium transition metal oxide represented by the chemical formula X as a positive electrode active material, and uses a first additive (containing tris(trimethylsilyl)phosphate) and a second additive (containing a cyclic sulfur oxide represented by the chemical formula 1) in combination as additives for the non-aqueous electrolyte. Due to the organic action of the first additive and the second additive added to the non-aqueous electrolyte, the lithium secondary battery according to one embodiment of the present invention can form a coating on the positive electrode that reduces resistance and has excellent durability, and can particularly improve the life and storage performance of lithium secondary batteries that are required to be used at high voltages.

[0036] On the other hand, Li[Ni 0.8 Co 0.1 Mn 0.1 High-nickel lithium transition metal oxides such as Li[O2 have a relatively high Ni content in the transition metal or a high Ni / Mn molar ratio, and the change in the axis of the lattice due to the increase and decrease in the Ni oxidation number during charging and discharging is large. Therefore, the surface side reactions become intense due to the unstable Ni in terms of energy, and it is difficult to realize the performance improvement effect of forming a positive electrode film using an additive. 0.8 Co 0.1 Mn 0.1 High nickel lithium transition metal oxides such as Li[Ni]O2 have a relatively high Ni / Mn molar ratio, so when driven at high voltage, a large amount of rock-salt structure is present on the surface due to a phase change. This makes it difficult to intercalate and deintercalate lithium ions and form a positive electrode film by combining the above additives. 0.6 Co 0.2 Mn 0.2Lithium transition metal oxides that do not satisfy the chemical formula X, such as ]O2, have a relatively high proportion of Co in the transition metal, which increases irreversibility within the structure, making it difficult to achieve performance improvement effects through the formation of a positive electrode film using an additive. In contrast, the compound represented by the chemical formula X can easily improve the desired lifespan and storage performance by using the first additive and the second additive in combination.

[0037] In the chemical formula X, x may be about 0≦x≦0.5, for example, about 0≦x≦0.2.

[0038] In the chemical formula X, a may be about 0.5≦a≦0.7, for example, about 0.55≦a≦0.65.

[0039] In the formula X, b is about 0≦b≦0.15. b corresponds to the molar percentage of Co among the metals excluding lithium in the lithium transition metal oxide represented by the formula X. According to one embodiment of the present invention, a low Co content can provide cost benefits, and a relatively high Mn content can improve the structural stability of the positive electrode active material. For example, in the formula X, b may be about 0≦b≦0.1.

[0040] In the formula X, b / a is about 0≦b / a≦0.2. If b / a exceeds 0.2, the proportion of Co in the transition metal is relatively high, increasing irreversibility within the structure, which may limit the performance improvement effect achieved by the formation of a positive electrode film by the additive. For example, in the formula X, b / a may be about 0.05≦b / a≦0.2.

[0041] In the formula X, c = 1-abd, and a / c is about 1≦a / c≦3. c corresponds to the molar percentage of Mn among the metals excluding lithium in the lithium transition metal oxide represented by the formula X. According to one embodiment of the present invention, the molar ratio of Ni to Mn is adjusted to about 1≦a / c≦3, thereby improving the structural stability of the positive electrode active material. For example, a / c may be about 1.5≦a / c≦2.5.

[0042] In the above chemical formula X, M 1 may be understood as a doping element of the lithium transition metal oxide, and may be, for example, one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo. In this case, d may be about 0≦d≦0.1, for example, about 0≦d≦0.05.

[0043] In the formula X, a / (b×c) may be about 18 to 50, for example, about 18 to 40, or about 20 to 35. When the ratio is within the above range, the contents of nickel, cobalt, and manganese in the formula A are well-balanced, which can improve both the performance improvement effect due to the formation of a positive electrode coating by the additive and the structural stability of the positive electrode active material.

[0044] The positive electrode active material may be in the form of particles. Specifically, the positive electrode active material may be in the form of a single particle consisting of one single nodule, or a quasi-single particle which is a composite of 30 or less nodules. Alternatively, the positive electrode active material may be in the form of a quasi-single particle which is a composite of 2 to 20, for example, 2 to 10, nodules, or a form containing these. In this case, particle cracking during electrode manufacturing of the positive electrode active material is prevented, and internal cracking due to volume expansion / contraction of the nodules during charge / discharge is prevented, thereby improving high-temperature life characteristics and high-temperature storage characteristics.

[0045] The average particle size (D 50 ) may be about 1 μm to 10 μm, for example, about 2 μm to 8 μm, or about 3 μm to 7 μm, or about 3 μm to 5 μm, or about 3.5 μm to 4.5 μm. When the thickness satisfies the above range, the processability during electrode production is excellent, the electrolyte impregnation is high, the electrochemical properties are improved, and the resistance is reduced, resulting in improved output characteristics.

[0046] The specific surface area of ​​the positive electrode active material is about 0.1 m 2 / g~3.0m 2 / g, for example, about 0.3 m 2 / g~2.5m 2 / g, or approximately 0.4m 2 / g~1.8m 2 / g, or approximately 0.5m 2 / g~1.0m 2 / g, or approximately 0.7m 2 / g~0.9m 2 When the above range is satisfied, the rolling characteristics of the electrode can be improved, particle cracking can be reduced, and side reactions with the electrolyte can be suppressed.

[0047] The positive electrode may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode active material is contained in the positive electrode active material layer.

[0048] The positive electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. For example, the positive electrode current collector may include at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, and an aluminum-cadmium alloy, and in one embodiment, may include aluminum.

[0049] The positive electrode current collector usually has a thickness of about 3 μm to 500 μm.

[0050] The positive electrode current collector may have a surface with fine irregularities to enhance the bonding strength of the positive electrode active material. For example, the positive electrode current collector may be used in various forms such as a film, sheet, foil, mesh, porous material, foam, or nonwoven fabric.

[0051] The positive electrode active material layer may be disposed on at least one surface of the positive electrode current collector, specifically, on one or both surfaces of the positive electrode current collector.

[0052] The positive electrode active material may be contained in the positive electrode active material layer in an amount of about 80% by weight to 99% by weight, for example, about 92% by weight to 98.5% by weight, in consideration of sufficient capacity of the positive electrode active material.

[0053] Other details about the positive electrode active material have been described above and will be omitted here.

[0054] The positive electrode active material layer may further include a binder and / or a conductive material in addition to the positive electrode active material.

[0055] The binder is a component that assists in binding the active material and conductive material, etc., and in binding to the current collector, and may include, for example, at least one selected from the group consisting of polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, and fluororubber, or in one embodiment, may include polyvinylidene fluoride.

[0056] The binder may be contained in the positive electrode active material layer in an amount of about 1 wt % to 20 wt %, for example, about 1.2 wt % to 10 wt %, from the viewpoint of ensuring sufficient binding strength between components such as the positive electrode active material.

[0057] The conductive material is used to assist and improve the conductivity of the secondary battery, and is not particularly limited as long as it does not cause chemical changes and has conductivity. For example, the positive electrode conductive material may include at least one selected from the group consisting of graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives. In one embodiment, the conductive material may include carbon nanotubes from the viewpoint of improving conductivity.

[0058] From the viewpoint of ensuring sufficient electrical conductivity, the conductive material may be contained in the positive electrode active material layer in an amount of about 1% by weight to 20% by weight, for example, about 1.2% by weight to 10% by weight.

[0059] The thickness of the positive electrode active material layer may be about 30 μm to 400 μm, for example, about 40 μm to 200 μm.

[0060] The positive electrode may be fabricated by coating a positive electrode slurry containing a positive electrode active material, and optionally a binder, a conductive material, and a solvent for forming the positive electrode slurry, on the positive electrode current collector, followed by drying and rolling.

[0061] The solvent for forming the positive electrode slurry may include an organic solvent such as N-methyl-2-pyrrolidone (NMP), and the solid content of the positive electrode slurry may be about 40% by weight to 90% by weight, for example, about 50% by weight to 80% by weight.

[0062] (2) Negative electrode The negative electrode faces the positive electrode.

[0063] The negative electrode includes a negative electrode active material.

[0064] The negative electrode active material is a material capable of reversibly intercalating / deintercalating lithium ions, and may include at least one selected from the group consisting of a carbon-based active material, a (quasi-)metal-based active material, and lithium metal, for example, at least one selected from a carbon-based active material and a (quasi-)metal-based active material.

[0065] 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 include, for example, at least one selected from the group consisting of artificial graphite and natural graphite.

[0066] The average particle size (D 50 ) may be about 10 μm to 30 μm, for example, about 15 μm to 25 μm, from the viewpoint of improving structural stability during charge and discharge and reducing side reactions with the electrolyte.

[0067] For example, the (quasi-)metallic active material may include at least one (quasi-)metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; an alloy of at least one (quasi-)metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; an oxide of at least one (quasi-)metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; lithium titanium oxide (LTO); lithium vanadium oxide; or the like.

[0068] In one embodiment, the (quasi)metallic active material may include a silicone-based active material.

[0069] The silicone-based active material is SiO x (0≦x<2) Since SiO2 does not react with lithium ions and therefore cannot store lithium, x is selected within the above range, excluding 2, and in one embodiment, the silicone-based active material may be SiO.

[0070] The average particle size (D 50 ) may be about 1 μm to 30 μm, for example, about 2 μm to 15 μm, from the viewpoint of improving structural stability during charge and discharge and reducing side reactions with the electrolyte.

[0071] The negative electrode may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active material is contained in the negative electrode active material layer.

[0072] The negative electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. For example, the negative electrode current collector may be made of copper, stainless steel, aluminum, nickel, titanium, baked carbon, copper or stainless steel whose surface is treated with carbon, nickel, titanium, silver, or the like, or an aluminum-cadmium alloy.

[0073] The negative electrode current collector usually has a thickness of about 3 μm to 500 μm.

[0074] The negative electrode current collector may have a surface with fine irregularities to enhance the bonding strength 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 material, foam, or nonwoven fabric.

[0075] The negative electrode active material layer may be disposed on at least one surface of the negative electrode current collector, specifically, on one or both surfaces of the negative electrode current collector.

[0076] The negative electrode active material may be contained in the negative electrode active material layer in an amount of about 60% to 99% by weight, for example, about 75% to 95% by weight.

[0077] Other details about the positive electrode active material have been described above and will be omitted here.

[0078] The negative electrode active material layer may further include a binder and / or a conductive material in addition to the negative electrode active material.

[0079] The binder is used to improve the adhesive strength between the negative electrode active material layer and the negative electrode current collector, thereby improving battery performance. For example, the binder may include at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, and substances in which hydrogen is substituted with Li, Na, Ca, or the like, or may include various copolymers thereof.

[0080] The binder may be included in the negative electrode active material layer in an amount of about 0.5% by weight to 10% by weight, for example, about 1% by weight to 5% by weight.

[0081] The conductive material is not particularly limited as long as it does not cause a chemical change in the battery and is conductive. For example, graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives may be used.

[0082] The conductive material may be contained in the negative electrode active material layer in an amount of about 0.5% by weight to 10% by weight, for example, about 1% by weight to 5% by weight.

[0083] The thickness of the negative electrode active material layer may be about 10 μm to 200 μm, for example, about 20 μm to 150 μm.

[0084] The negative electrode may be prepared by coating at least one surface of a negative electrode current collector with a negative electrode slurry containing a negative electrode active material, a binder, a conductive material, and / or a solvent for forming the negative electrode slurry, followed by drying and rolling.

[0085] The solvent for forming the negative electrode slurry may include, for example, at least one selected from the group consisting of distilled water, N-methyl-2-pyrrolidone (NMP), ethanol, methanol, and isopropyl alcohol, from the viewpoint of facilitating dispersion of the negative electrode active material, binder, and / or conductive material, or in one embodiment, may include distilled water. The solid content of the negative electrode slurry may be about 30% by weight to 80% by weight, for example, about 40% by weight to 70% by weight.

[0086] (3) Separator The separator may be interposed between the positive electrode and the negative electrode.

[0087] The separator may be a conventional porous polymer film, such as a porous polymer film made of a polyolefin polymer such as an ethylene homocopolymer, a propylene homocopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, either alone or in a laminate, or a conventional porous nonwoven fabric, such as a nonwoven fabric made of a high-melting point glass fiber or polyethylene terephthalate fiber, but is not limited to these. Furthermore, to ensure heat resistance or mechanical strength, a coated separator containing a ceramic component or a polymer material may be used, and may be selectively used as a single-layer or multi-layer structure.

[0088] (4) Nonaqueous electrolyte The non-aqueous electrolyte includes a lithium salt, an organic solvent, and an additive.

[0089] 1) Lithium salt As the lithium salt used in the present invention, various lithium salts that are commonly used in non-aqueous electrolytes for lithium secondary batteries can be used without any limitation. For example, the lithium salt may contain Li as a cation. + and as an anion, F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , B 10 Cl 10 - , BF2C2O4 - , BC4O8 - , PF4C2O4 - , PF2C4O8 - , (CF3)2PF4 - , (CF3)3PF3 -, (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , CH3SO3 - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , and (CF3CF2SO2)2N - The present invention may include at least one selected from the group consisting of:

[0090] For example, the lithium salt may be LiCl, LiBr, LiI, LiBF, LiClO, LiAlO, LiAlCl, LiPF, LiSbF, LiAsF, LiB 10 Cl 10 , LiBOB (LiB(C2O4)2), LiCF3SO3, LiFSI (LiN(SO2F)2), LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI (LiN(SO2CF2CF3)2). For example, the lithium salt may include at least one selected from the group consisting of LiBF4, LiClO4, LiPF6, LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiFSI ((LiN(SO2F)2), and LiBETI (LiN(SO2CF2CF3)2).

[0091] The lithium salt may be contained in the non-aqueous electrolyte at a concentration of about 0.5 M to 5 M, for example, about 0.8 M to 4 M, or about 0.8 M to 2.0 M. When the concentration of the lithium salt satisfies the above range, the lithium ion transport number (Li +The transference number and dissociation degree of lithium ions are improved, which can improve the output characteristics of the battery.

[0092] 2) Organic solvents The organic solvent is not particularly limited as long as it is a non-aqueous solvent commonly used in lithium secondary batteries and minimizes decomposition due to oxidation reactions during charging and discharging of the secondary battery.

[0093] For example, the organic solvent may include at least one selected from the group consisting of cyclic carbonate organic solvents, linear carbonate organic solvents, linear ester organic solvents, and cyclic ester organic solvents.

[0094] For example, the organic solvent may include a cyclic carbonate organic solvent, a linear carbonate organic solvent, or a mixture thereof.

[0095] The cyclic carbonate organic solvent is a highly viscous organic solvent that has a high dielectric constant and easily dissociates the lithium salt in the electrolyte. For example, the cyclic carbonate organic solvent may include at least one organic solvent selected from the group consisting of ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate, or may include at least one organic solvent selected from the group consisting of ethylene carbonate (EC) and fluoroethylene carbonate (FEC), and in one embodiment, may include ethylene carbonate (EC).

[0096] The linear carbonate organic solvent is an organic solvent having low viscosity and low dielectric constant, and may include, for example, at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate, and ethyl propyl carbonate, or may include at least one selected from the group consisting of ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), and in one embodiment, may include ethyl methyl carbonate (EMC).

[0097] The organic solvent may be a mixture of a cyclic carbonate organic solvent and a linear carbonate organic solvent. In this case, the cyclic carbonate organic solvent and the linear carbonate organic solvent may be mixed at a volume ratio of about 5:95 to 40:60, for example, 8:92 to 35:65, or 10:90 to 25:75. When the mixing ratio of the cyclic carbonate organic solvent and the linear carbonate organic solvent satisfies the above range, both high dielectric constant and low viscosity characteristics are satisfied, and excellent ionic conductivity characteristics can be achieved.

[0098] In order to produce an electrolyte having high ionic conductivity, the organic solvent may further contain at least one ester organic solvent selected from the group consisting of linear ester organic solvents and cyclic ester organic solvents in addition to the at least one carbonate organic solvent selected from the group consisting of cyclic carbonate organic solvents and linear carbonate organic solvents.

[0099] The linear ester organic solvent may include, for example, at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate.

[0100] The cyclic ester organic solvent may contain, for example, at least one selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone.

[0101] Meanwhile, the organic solvent may further include, as needed, any organic solvent commonly used in non-aqueous electrolytes, for example, at least one of an ether-based organic solvent, a glyme-based organic solvent, and a nitrile-based organic solvent.

[0102] The ether solvent may be any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether, ethyl propyl ether, 1,3-dioxolane (DOL), and 2,2-bis(trifluoromethyl)-1,3-dioxolane (TFDOL), or a mixture of two or more of these, but is not limited thereto.

[0103] The glyme-based solvent has a higher dielectric constant and lower surface tension than linear carbonate-based organic solvents and is less reactive with metals, and may include at least one selected from the group consisting of dimethoxyethane (glyme, DME), diethoxyethane, diglyme, triglyme, and tetraglyme (TEGDME), but is not limited thereto.

[0104] The nitrile solvent may be one or more selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile, but is not limited thereto.

[0105] 3) Additives The non-aqueous electrolyte contains an additive.

[0106] The additives include a first additive and a second additive.

[0107] The first additive is a phosphate-based additive containing a silyl group, and includes, for example, tris(trimethylsilyl)phosphate (TMSPa).

[0108] The tris(trimethylsilyl)phosphate can be decomposed to form PO radicals, which can form a PO-based coating on the positive electrode. The tris(trimethylsilyl)phosphate can also function as an HF scavenger to remove decomposition products of lithium salts (e.g., PF5, HF) generated during the charge / discharge process of a lithium secondary battery.

[0109] Meanwhile, although tris(trimethylsilyl)phosphate is used as the first additive, the first additive is not limited thereto, and any other substance may be used as long as it can be decomposed to form PO radicals, thereby forming a PO-based coating on the positive electrode, or can function as an HF scavenger to remove decomposition products of lithium salts (PF5, HF, etc.) generated during the charge and discharge process of a lithium secondary battery.

[0110] However, the PO radical generated from tris(trimethylsilyl)phosphate has a relatively fast reaction rate, forming a monomolecular coating rather than a polymeric coating due to a chain reaction. Therefore, when tris(trimethylsilyl)phosphate is used alone, it is difficult to form a coating with sufficient coverage on the positive electrode. However, the present invention uses a first additive and a second additive in combination, resulting in the formation of a coating on the positive electrode with excellent lithium mobility, coverage, and durability, thereby improving the lifespan and high-temperature storage performance of the lithium secondary battery.

[0111] The first additive may be included in the non-aqueous electrolyte in an amount of about 0.01 wt % to 10 wt %, for example, about 0.05 wt % to 7 wt %, about 0.1 wt % to 5 wt %, or about 1 wt % to 4 wt %. When the first additive is used in the above content range, the aforementioned effects of improving the life performance and high-temperature storage performance can be achieved, and the risk of an increase in resistance when an excessive amount is added can be prevented.

[0112] The second additive includes, for example, a compound represented by the following Chemical Formula 1:

[0113] [Chemical formula 1] [ka]

[0114] In the above chemical formula 1, n is 1 or 2, L1 and L2 each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, and R1 and R2 each independently represent a substituent represented by the following chemical formula 2: [Chemical formula 2] [ka] In the above Chemical Formula 2, m is 1 or 2, and X1 and X2 each independently represent -O- or -C(R 31 )(R 32)-, wherein at least one of X1 and X2 is -O-, and R 31 ~R 36 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -C(=O)-R4, or -R5-OC(=O)-R6, and R4 and R6 are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, R5 is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, and L1, L The substituents of R2, R4, R5, and R6 are each independently one or more selected from the group consisting of deuterium, -F, -Cl, -Br, -I, -CN, -NO2, and -SO3, and * indicates the position of bonding to L1 or L2. When both L1 and L2 are direct bonds, R1 and R2 are not simultaneously CS-7 below; when both L1 and L2 are methylene groups and n is 2, R1 and R2 are not simultaneously CS-2 below. [ka]

[0115] The compound represented by Chemical Formula 1 is characterized by having a sulfur oxide structure at the center and cyclic sulfur oxide structures at both ends. By adopting such a chemical structure, when used as a nonaqueous electrolyte additive, it is possible to induce stable formation of anions and further to form a stable SEI (Solid Electrolyte Interphase) layer.

[0116] On the other hand, the compound represented by Chemical Formula 1 forms a coating on the positive electrode through the ring-opening reaction of cyclic sulfur oxides, but its steric hindrance results in a low reaction participation rate. Therefore, when the compound represented by Chemical Formula 1 is used alone, its low reaction participation rate makes it difficult to form the desired positive electrode coating. However, the present invention uses a first additive and a second additive in combination. PO radicals are formed from the first additive, and the PO radicals promote the ring-opening reaction of the compound represented by Chemical Formula 1. As a result, a positive electrode coating rich in oxygen (O) is formed based on sulfur (S) and phosphorus (P), thereby realizing a lithium secondary battery with excellent lithium mobility, life performance, and storage performance. Furthermore, when the first additive and the second additive are used in combination, the formation of PO radicals by the first additive and the promotion of the ring-opening reaction of the second additive by the radicals result in the formation of a coating on the positive electrode with excellent coverage and improved durability.

[0117] On the other hand, in addition to the above-mentioned second additive, any other additive can be applied as the second additive as long as it is an additive that can easily undergo, for example, a ring-opening reaction by radicals when combined with the first additive.

[0118] The effect of improving the life performance and storage performance due to the organic action of the first additive and the second additive becomes more pronounced when used at high voltage, and this effect is particularly evident when the lithium transition metal oxide represented by the above-mentioned chemical formula X is used as the positive electrode active material.

[0119] For example, in the compound represented by Chemical Formula 1, R1 and R2 may each independently be selected from the group consisting of the following CS-1 to CS-15. [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0120] The substituent structures CS-1 to CS-15 listed above are preferred examples of R1 and R2 in Chemical Formula 1, and when the substituents CS-1 to CS-15 are applied to R1 and R2 in Chemical Formula 1, the overall compound has excellent structural stability and can smoothly function as an additive for a non-aqueous electrolyte. For example, it is preferred that R1 and R2 are each independently any one selected from the group consisting of CS-1, CS-2, CS-5, CS-8, CS-10, and CS-11 in terms of structural stability and ease of synthesis.

[0121] On the other hand, in the compound represented by Chemical Formula 1 of the present invention, when both L1 and L2 are direct bonds and R1 and R2 are CS-7, or when both L1 and L2 are methylene groups, n is 2, and R1 and R2 are both CS-2, the compound itself has low structural stability and is easily decomposed, which may make synthesis of the compound difficult. In particular, compounds that satisfy the above conditions have the disadvantage that the ring-shaped R1 and R2 structures are easily decomposed during the synthesis process, and even if the compound is finally synthesized, it is easily decomposed during storage and has a significantly low synthesis yield. Therefore, the present invention excludes compounds when both L1 and L2 are direct bonds and R1 and R2 are CS-7, and compounds when n is 2 and R1 and R2 are both CS-2.

[0122] In the compound represented by Chemical Formula 1, L1 and L2 may each independently represent a direct bond, a methylene group, or an ethylene group, and in one embodiment, may represent a methylene group. When L1 and L2 are methylene groups, the compound can be easily synthesized and decomposition of the compound after synthesis can be suppressed.

[0123] For example, the compound represented by Chemical Formula 1 may be any one selected from the group consisting of the following compounds A to R. [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0124] When the compound represented by Chemical Formula 1 has the structure described above, it has the advantage that a low resistance and stable SEI layer can be formed even with a smaller content than conventionally used additives.

[0125] The compound represented by Chemical Formula 1 may be included in the non-aqueous electrolyte at about 0.01 wt % to 10 wt %, for example, about 0.05 wt % to 7 wt %, about 0.1 wt % to 5 wt %, or about 1 wt % to 4 wt %. This range is preferable in that it not only improves the life and storage performance of the secondary battery, but also prevents an increase in resistance due to the use of excessive additives.

[0126] Meanwhile, in addition to the second additives described above, any other compounds that can achieve similar functions and effects can be used as the second additive.

[0127] The weight ratio of the first additive to the second additive may be about 1:99 to 99:1, for example, about 30:70 to 70:30, or 40:60 to 60:40. When the weight ratio is as described above, the effects of using the first additive and the second additive in combination are well balanced, and as a result, the effects of improving the high-temperature life performance and high-temperature storage performance of the lithium secondary battery can be more preferably exhibited.

[0128] The additive may further include an additional additive together with the first additive, or together with the first additive and the second additive. The additional additive may be included in the non-aqueous electrolyte to prevent the non-aqueous electrolyte from decomposing and causing the negative electrode to collapse in a high-power environment, or to improve low-temperature high-rate discharge characteristics, high-temperature stability, prevent overcharge, and suppress battery expansion at high temperatures.

[0129] For example, the additional additive may be at least one selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, propane sultone, propene sultone, 1,4-butane sultone, ethane sultone, succinonitrile, adiponitrile, ethylene sulfate, lithium difluoro phosphate (LiDFP), lithium tetrafluoroborate (LiBF), lithium difluoro(oxalato)borate (LiODFB), lithium bis-(oxalato)borate (LiBOB), and tris(trimethylsilyl)phosphate (TMSPi).

[0130] The additional additive may be included in the non-aqueous electrolyte in an amount of about 0.1 wt % to 15 wt %.

[0131] The driving voltage of the lithium secondary battery according to one embodiment of the present invention may be about 4.35 V or more, for example, about 4.4 V or more. The lithium secondary battery according to one embodiment of the present invention can achieve excellent energy density at a high driving voltage, as well as improved life performance and storage performance, by combining the above-described positive electrode and non-aqueous electrolyte.

[0132] The external shape of the lithium secondary battery of the present invention is not particularly limited, and may be a cylindrical shape using a can, a square shape, a pouch shape, a coin shape, or the like.

[0133] The present invention will be described below with reference to examples. However, the following examples are merely illustrative for understanding the present invention and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art that various modifications and alterations are possible within the scope and technical concept of the present description, and it goes without saying that such modifications and alterations fall within the scope of the appended claims.

[0134] Examples and Comparative Examples Example 1 (Production of non-aqueous electrolyte) The organic solvent used was a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 20:80.

[0135] To the organic solvent, LiPF6 as a lithium salt, tris(trimethylsilyl)phosphate (TMSPa) as a first additive, and the compound A as a second additive were added to prepare a non-aqueous electrolyte.

[0136] The LiPF6 was contained in the non-aqueous electrolyte at a molar concentration of 1.2M.

[0137] The first additive was contained in the non-aqueous electrolyte at 0.1 wt %, and the second additive was contained in the non-aqueous electrolyte at 0.1 wt %.

[0138] (Lithium secondary battery manufacturing) Cathode active material (Li[Ni 0.60 Co 0.05 Mn 0.35]O2), a conductive material (carbon nanotubes), and a binder (polyvinylidene fluoride) were added to a solvent, N-methyl-2-pyrrolidone (NMP), in a weight ratio of 97.74:0.70:1.56 to prepare a positive electrode slurry (solid content 75.5 wt%). The positive electrode slurry was applied to one side of a 15 μm-thick positive electrode current collector (Al thin film), dried, and roll-pressed to form a positive electrode active material layer (thickness: 136.6 μm), which served as the positive electrode. The positive electrode active material was in the form of single particles or pseudo-single particles.

[0139] A negative electrode slurry (26 wt% solids) was prepared by adding a negative electrode active material (natural graphite), a conductive material (carbon black), and binders (styrene-butadiene rubber and carboxymethyl cellulose) in a weight ratio of 96.15:1.55:2.30 to distilled water as a solvent. The negative electrode slurry was applied to one side of a 15 μm-thick negative electrode current collector (Cu thin film), dried, and roll-pressed to form a negative electrode active material layer (thickness: 179.8 μm), which served as the negative electrode.

[0140] A polyethylene porous film separator was interposed between the positive electrode and negative electrode prepared above in a dry room, and the non-aqueous electrolyte prepared above was then injected to prepare a secondary battery.

[0141] Example 2 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the second additive was added to the non-aqueous electrolyte in an amount of 5 wt % instead of 0.1 wt % in Example 1.

[0142] Example 3 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the first additive was added to the non-aqueous electrolyte at a content of 3 wt % instead of 0.1 wt % in Example 1, and the second additive was added to the non-aqueous electrolyte at a content of 3 wt % instead of 0.1 wt % in Example 1.

[0143] Example 4 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the first additive was added to the non-aqueous electrolyte in an amount of 5 wt % instead of 0.1 wt % in Example 1.

[0144] Example 5 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the first additive was added to the non-aqueous electrolyte at a content of 5 wt % instead of 0.1 wt % in Example 1, and the second additive was added to the non-aqueous electrolyte at a content of 5 wt % instead of 0.1 wt % in Example 1.

[0145] Example 6 A lithium secondary battery was manufactured in the same manner as in Example 3, except that, as the second additive, compound F was added to the non-aqueous electrolyte in an amount of 3 wt % instead of compound A in Example 1.

[0146] Example 7 A lithium secondary battery was manufactured in the same manner as in Example 3, except that, as the second additive, compound J was added to the non-aqueous electrolyte in an amount of 3 wt % instead of compound A in Example 1.

[0147] Comparative Example 1 A lithium secondary battery was produced in the same manner as in Example 1, except that the second additive was not added to the non-aqueous electrolyte.

[0148] Comparative Example 2 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the first additive was added to the non-aqueous electrolyte at a content of 5 wt % instead of 0.1 wt % in Example 1, and the second additive was not added to the non-aqueous electrolyte.

[0149] Comparative Example 3 A lithium secondary battery was produced in the same manner as in Example 1, except that the first additive was not added to the non-aqueous electrolyte.

[0150] Comparative Example 4 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the first additive was not added to the non-aqueous electrolyte, and the second additive was added to the non-aqueous electrolyte at a content of 5 wt % instead of 0.1 wt %.

[0151] Comparative Example 5 A lithium secondary battery was manufactured in the same manner as in Example 3, except that the following comparative compound was added to the non-aqueous electrolyte at a content of 3 wt % as the second additive instead of compound A in Example 1.

[0152] [Comparative compounds] [ka]

[0153] [Table 1]

[0154] Experimental example Experimental example 1: Evaluation of high-temperature cycle performance The lithium secondary batteries of Examples 1 to 7 and Comparative Examples 1 to 5 manufactured as described above were subjected to 300 charge / discharge cycles using an electrochemical charger / discharger, where one cycle was defined as charging at 45°C under CC / CV conditions at 0.33C to 4.4V, 0.05C, and then discharging under CC conditions at 0.33C to 2.5V.

[0155] (1) Capacity maintenance rate The capacity retention rate was calculated using the following formula, and the results are shown in Table 2 below.

[0156] Capacity retention rate (%) = {(discharge capacity after 300 cycles / discharge capacity after 1 cycle)} × 100

[0157] (2) Resistance increase rate After one charge / discharge cycle, the discharge capacity after one cycle was measured using an electrochemical charger / discharger, and the SOC (State of Charge) was adjusted to 50%. A 2.5C pulse was then applied for 10 seconds, and the initial resistance was calculated from the difference in voltage before and after the pulse application.

[0158] After 300 cycles of charge and discharge, the resistance after 300 cycles was calculated in the same manner as above, and the resistance increase rate was calculated using the following formula. The results are shown in Table 2 below.

[0159] Resistance increase rate (%) = (resistance after 300 cycles - initial resistance) / initial resistance x 100

[0160] [Table 2]

[0161] Referring to Table 2, it can be seen that the lithium secondary batteries of Examples 1 to 7, which combined a positive electrode containing a lithium transition metal oxide represented by chemical formula X with a nonaqueous electrolyte of the present invention containing the first additive and the second additive as additives, had a higher capacity retention rate and a lower resistance increase rate during high-temperature cycle charge / discharge at a high voltage, compared to Comparative Examples 1 to 5, which did not employ the present invention.

[0162] Experimental example 2: Evaluation of high-temperature storage performance The lithium secondary batteries of Examples 1 to 7 and Comparative Examples 1 to 5 prepared above were initially charged and discharged using an electrochemical charger / discharger at 25°C under CC / CV conditions at 0.33C up to 4.4V, 0.05C, and then discharged at CC, 0.33C down to 2.5V. Subsequently, they were charged at 25°C under CC / CV conditions at 0.33C up to 4.4V, 0.05C, and then stored at 60°C for 12 weeks.

[0163] (1) Capacity maintenance rate After 12 weeks of storage, the lithium secondary battery was charged to 4.4 V, 0.05 C under CC / CV, 0.33 C conditions at 25°C using an electrochemical charger / discharger, and then discharged to 2.5 V at CC, 0.33 C, and the capacity at discharge was measured.

[0164] The capacity retention rate was evaluated using the following formula, and the results are shown in Table 3 below.

[0165] Capacity retention rate (%) = (discharge capacity after 12 weeks of storage / initial discharge capacity) x 100

[0166] (2) Resistance increase rate After the initial charge and discharge, the capacity was confirmed at room temperature, and then the battery was charged to 50% SOC based on the discharge capacity and discharged at a current of 2.5 C for 10 seconds. The resistance was measured from the difference in voltage drop at this time and recorded as the initial resistance. After storing the battery at 60°C for 12 weeks, the resistance was measured in the same manner and recorded as the final resistance. The resistance increase rate was calculated using the following formula. The results are shown in Table 3 below.

[0167] Resistance increase rate (%) = (final resistance - initial resistance) / (initial resistance) x 100

[0168] [Table 3]

[0169] Referring to Table 3, it can be seen that the lithium secondary batteries of Examples 1 to 7, which combined a positive electrode containing a lithium transition metal oxide represented by chemical formula X with a nonaqueous electrolyte of the present invention containing the first additive and the second additive as additives, had a higher capacity retention rate and a lower resistance increase rate during high-temperature storage than the batteries of Comparative Examples 1 to 5, which did not employ the contents of the present invention.

[0170] Reference Example A: Li[Ni 0.8 Co 0.1 Mn 0.1 ]When O2 is used Reference Example 1A (1) Production of non-aqueous electrolyte The organic solvent used was a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 20:80.

[0171] To the organic solvent, LiPF6 as a lithium salt, tris(trimethylsilyl)phosphate (TMSPa) as a first additive, and the compound A as a second additive were added to prepare a non-aqueous electrolyte.

[0172] The LiPF6 was contained in the non-aqueous electrolyte at a molar concentration of 1.2M.

[0173] The first additive was contained in the non-aqueous electrolyte at 5 wt %, and the second additive was contained in the non-aqueous electrolyte at 5 wt %.

[0174] (2) Manufacture of lithium secondary batteries Cathode active material (Li[Ni 0.8 Co 0.1 Mn 0.1 ]O2) (high nickel lithium transition metal oxide), conductive material (carbon nanotubes), and binder (PVDF) were added to N-methyl-2-pyrrolidone (NMP) as a solvent in a weight ratio of 96.78:1.20:2.02 to prepare a cathode mixture slurry (solid content 75.5 wt%). The cathode mixture slurry was applied to one side of a 15 μm-thick cathode current collector (Al thin film), dried, and roll-pressed to prepare a cathode.

[0175] Anode active material (natural graphite), conductive material (carbon black), and binders (styrene-butadiene rubber and carboxymethyl cellulose) were mixed in a weight ratio of 96.15:0.50:3.35 with distilled water as a solvent to prepare anode mixture slurry (solid content 26 wt%). The anode mixture slurry was applied to one side of a 15 μm-thick anode current collector (Cu thin film), dried, and roll-pressed to prepare anode.

[0176] A polyethylene porous film separator was interposed between the positive electrode and negative electrode prepared above in a dry room, and the non-aqueous electrolyte prepared above was then injected to prepare a secondary battery.

[0177] Reference example 2A A lithium secondary battery was produced in the same manner as in Reference Example 1A, except that the second additive was not added to the non-aqueous electrolyte.

[0178] Reference example 3A A lithium secondary battery was produced in the same manner as in Reference Example 1A, except that the first additive was not added to the non-aqueous electrolyte.

[0179] Reference Experiment Example A-1 The lithium secondary batteries of Reference Examples 1A to 3A manufactured above were charged to 4.2 V, 1 / 40 C under CC / CV, 0.33 C conditions at 45°C using an electrochemical charger / discharger, and then discharged to 2.5 V under CC, 0.33 C conditions, with one cycle being defined as 300 charge / discharge cycles.

[0180] (1) Capacity maintenance rate The capacity retention rate was calculated using the following formula, and the results are shown in Table 4 below.

[0181] Capacity retention rate (%) = {(discharge capacity after 300 cycles / discharge capacity after 1 cycle)} × 100

[0182] (2) Resistance increase rate After one charge / discharge cycle, the discharge capacity after one cycle was measured using an electrochemical charge / discharge device, and after adjusting the SOC to 50%, a 2.5C pulse was applied for 10 seconds, and the initial resistance was calculated from the difference in voltage before and after the pulse application.

[0183] After 300 cycles of charge and discharge, the resistance after 300 cycles was calculated in the same manner as above, and the resistance increase rate was calculated using the following formula. The results are shown in Table 4 below.

[0184] Resistance increase rate (%) = (resistance after 300 cycles - initial resistance) / initial resistance x 100

[0185] Reference Experiment Example A-2 The lithium secondary batteries of Reference Examples 1A to 3A prepared above were initially charged and discharged at 25°C under CC / CV and 0.33C conditions to 4.2V and 1 / 40C, and then discharged at CC and 0.33C to 2.5V. Subsequently, they were charged at 25°C under CC / CV and 0.33C conditions to 4.2V and 1 / 40C, and then stored at 60°C for 12 weeks.

[0186] (1) Capacity maintenance rate After 12 weeks of storage, the lithium secondary battery was charged to 4.2 V, 1 / 40 C under CC / CV, 0.33 C conditions at 25° C., and discharged to 2.5 V at CC, 0.33 C, and the discharge capacity was measured.

[0187] The capacity retention rate was evaluated using the following formula, and the results are shown in Table 4 below.

[0188] Capacity retention rate (%) = (discharge capacity after 12 weeks of storage / initial discharge capacity) x 100

[0189] (2) Resistance increase rate After the initial charge and discharge, the capacity was confirmed at room temperature, and then the battery was charged to 50% SOC based on the discharge capacity and discharged at a current of 2.5 C for 10 seconds. The resistance was measured from the difference in voltage drop at this time and recorded as the initial resistance. After storing the battery at 60°C for 12 weeks, the resistance was measured in the same manner and recorded as the final resistance. The resistance increase rate was calculated using the following formula. The results are shown in Table 4 below.

[0190] Resistance increase rate (%) = (final resistance - initial resistance) / (initial resistance) x 100

[0191] [Table 4]

[0192] Referring to Table 4, it can be seen that the lithium secondary battery of Reference Example 1A, although using the first and second additives as non-aqueous electrolyte additives, showed relatively little improvement in effect compared to Reference Examples 2A and 3A. For example, when using a high nickel lithium transition metal oxide (Li[Ni 0.8 Co 0.1 Mn 0.1 In Reference Examples 1A to 3A, in which ]O2) was used, the effect was not improved at all even when the first additive and the second additive were used in combination. On the contrary, the capacity retention rate of Reference Example 1A during cycle charge / discharge or high-temperature storage was equal to or lower than that of Reference Examples 2A and 3A.

[0193] Reference Example B: Li[Ni 0.6 Co 0.2 Mn 0.2 ]When O2 is used Reference example 1B (1) Production of non-aqueous electrolyte The organic solvent used was a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 20:80.

[0194] To the organic solvent, LiPF6 as a lithium salt, tris(trimethylsilyl)phosphate (TMSPa) as a first additive, and the compound A as a second additive were added to prepare a non-aqueous electrolyte.

[0195] The LiPF6 was contained in the non-aqueous electrolyte at a molar concentration of 1.2M.

[0196] The first additive was contained in the non-aqueous electrolyte at 5 wt %, and the second additive was contained in the non-aqueous electrolyte at 5 wt %.

[0197] (2) Manufacture of lithium secondary batteries Cathode active material (Li[Ni 0.6 Co 0.2 Mn 0.2]O2), a conductive material (carbon nanotubes), and a binder (PVDF) were added to a solvent, N-methyl-2-pyrrolidone (NMP), in a weight ratio of 97.74:0.70:1.56 to prepare a cathode mixture slurry (solid content 75.5 wt%). The cathode mixture slurry was applied to one side of a 15 μm-thick cathode current collector (Al thin film), dried, and roll-pressed to prepare a cathode.

[0198] Anode active material (natural graphite), conductive material (carbon black), and binders (styrene-butadiene rubber and carboxymethyl cellulose) were mixed in a weight ratio of 96.15:1.55:2.30 with distilled water as a solvent to prepare anode mixture slurry (solid content 26 wt%). The anode mixture slurry was applied to one side of a 15 μm-thick anode current collector (Cu thin film), dried, and roll-pressed to prepare anode.

[0199] A polyethylene porous film separator was interposed between the positive electrode and negative electrode prepared above in a dry room, and the non-aqueous electrolyte prepared above was then injected to prepare a secondary battery.

[0200] Reference example 2B A lithium secondary battery was produced in the same manner as in Reference Example 1B, except that the second additive was not added to the non-aqueous electrolyte.

[0201] Reference example 3B A lithium secondary battery was produced in the same manner as in Reference Example 1B, except that the first additive was not added to the non-aqueous electrolyte.

[0202] Reference Experiment Example B-1 The lithium secondary batteries of Reference Examples 1B to 3B manufactured above were charged to 4.4 V, 0.05 C under CC / CV conditions at 45°C and 0.33 C, and then discharged to 2.5 V under CC conditions at 0.33 C using an electrochemical charger / discharger, and 300 charge / discharge cycles were carried out.

[0203] (1) Capacity maintenance rate The capacity retention rate was calculated using the following formula, and the results are shown in Table 5 below.

[0204] Capacity retention rate (%) = {(discharge capacity after 300 cycles / discharge capacity after 1 cycle)} × 100

[0205] (2) Resistance increase rate After one charge / discharge cycle, the discharge capacity after one cycle was measured using an electrochemical charge / discharge device, and after adjusting the SOC to 50%, a 2.5C pulse was applied for 10 seconds, and the initial resistance was calculated from the difference in voltage before and after the pulse application.

[0206] After 300 cycles of charge and discharge, the resistance after 300 cycles was calculated in the same manner as above, and the resistance increase rate was calculated using the following formula. The results are shown in Table 5 below.

[0207] Resistance increase rate (%) = (resistance after 300 cycles - initial resistance) / initial resistance x 100

[0208] Reference Experiment Example B-2 The lithium secondary batteries of Reference Examples 1B to 3B prepared above were initially charged at 25° C. under CC / CV conditions at 0.33 C to 4.4 V at 0.05 C, and then discharged at CC conditions at 0.33 C to 2.5 V. Subsequently, they were charged at 25° C. under CC / CV conditions at 0.33 C to 4.4 V at 0.05 C, and then stored at 60° C. for 12 weeks.

[0209] (1) Capacity maintenance rate After 12 weeks of storage, the lithium secondary battery was charged at 25° C. under CC / CV, 0.33 C conditions to 4.4 V, 0.05 C, and then discharged at CC, 0.33 C to 2.5 V, and the discharge capacity was measured.

[0210] The capacity retention rate was evaluated using the following formula, and the results are shown in Table 5 below.

[0211] Capacity retention rate (%) = (discharge capacity after 12 weeks of storage / initial discharge capacity) x 100

[0212] (2) Resistance increase rate After the initial charge and discharge, the capacity was confirmed at room temperature, and then the battery was charged to 50% SOC based on the discharge capacity and discharged at a current of 2.5 C for 10 seconds. The resistance was measured from the difference in voltage drop at this time and recorded as the initial resistance. After storing the battery at 60°C for 12 weeks, the resistance was measured in the same manner and recorded as the final resistance. The resistance increase rate was calculated using the following formula. The results are shown in Table 4 below.

[0213] Resistance increase rate (%) = (final resistance - initial resistance) / (initial resistance) x 100

[0214] [Table 5]

[0215] Referring to Table 5, it can be seen that the lithium secondary battery of Reference Example 1B, although using the first and second additives as non-aqueous electrolyte additives, showed relatively little improvement in performance compared to Reference Examples 2B and 3B. For example, the positive electrode active material used was Li[Ni 0.6 Co 0.2 Mn 0.2 In Reference Examples 1B to 3B, in which ]O2 was used, the effect was not improved even when the first additive and the second additive were used in combination. On the contrary, the capacity retention rate of Reference Example 1B during cycle charge / discharge or high-temperature storage was equal to or lower than that of Reference Examples 2B and 3B.

[0216] Furthermore, referring to Tables 1, 2, and 5, it can be seen that Reference Example 1B has significantly reduced high-temperature life performance and high-temperature storage performance compared to Examples 1 to 5. From this, it can be seen that the effect of using the first additive and the second additive in combination according to one embodiment of the present invention is exerted specifically when the lithium transition metal oxide represented by the chemical formula X is used as the positive electrode active material.

[0217] Although the present invention has been described above with reference to preferred embodiments, it will be understood that those skilled in the art or those having ordinary knowledge in the art can make various modifications and changes to the present invention without departing from the spirit and technical scope of the present invention as defined in the appended claims. Therefore, the technical scope of the present invention is not limited to the contents described in the detailed description of the specification, but is determined solely by the claims.

Claims

1. a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte; the positive electrode includes a positive electrode active material, The positive electrode active material includes a lithium transition metal oxide represented by the following chemical formula X: the non-aqueous electrolyte contains a lithium salt, an organic solvent, and an additive; the additives include a first additive and a second additive; the first additive comprises a phosphate-based additive containing a silyl group; The second additive comprises a compound represented by the following Chemical Formula 1: [Chemical formula X] Li １＋ｘ [Ni ａ Co ｂ Mn ｃ M １ ｄ ]O ２＋ｗ (wherein in the chemical formula X, 0≦x≦0.5, a+b+c+d=1, 0.5≦a≦0.7, 0≦b≦0.15, c=1−a−b−d, 0≦d≦0.1, 0≦b / a≦0.2, 1≦a / c≦3, 0≦w≦1, M １ is one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo. [Chemical formula 1] 【Chemistry 1】 In the above Chemical Formula 1, n is 1 or 2; L １ and L ２ are each independently a direct bond or a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, R １ and R ２ are each independently a substituent represented by the following chemical formula 2: [Chemical formula 2] 【Chemistry 2】 In the above Chemical Formula 2, m is 1 or 2; X １ and X ２ are each independently —O— or —C(R ３１ ) (R ３２ )-, wherein said X １ and X ２ at least one of is —O—; R ３１ ~R ３６ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or —C(═O)—R ４ , or -R ５ -OC(=O)-R ６ and The R ４ and R ６ each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, The R ５ is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, Said L １ , L ２ , R ４ , R ５ , and R ６ The substituents are each independently deuterium, —F, —Cl, —Br, —I, —CN, or —NO ２ , and -SO ３ and one or more selected from the group consisting of: * indicates L １ or L ２ At the position where it binds to L １ and L ２ When both of R １ and R ２ At the same time, it is not the CS-7 below, L １ and L ２ are methylene groups and n is 2, １ and R ２ At the same time, it is not CS-2 below.) 【Transformation 3】

2. 2. The lithium secondary battery according to claim 1, wherein the first additive is tris(trimethylsilyl)phosphate.

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

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

5. The R １ and R ２ are each independently selected from the group consisting of the following CS-1 to CS-15: 【Chemistry 4】 【Transformation 5】 【Transformation 6】 【Transformation 7】 【Transformation 8】 【Chemistry 9】 【Chemistry 10】

6. The R １ and R ２ are each independently any one selected from the group consisting of CS-1, CS-2, CS-5, CS-8, CS-10, and CS-11.

7. Said L １ and L ２ The lithium secondary battery according to claim 1 , wherein is a methylene group.

8. 2. The lithium secondary battery of claim 1, wherein the compound represented by Chemical Formula 1 is any one selected from the group consisting of the following compounds A to R: 【Chemistry 11】 【Chemistry 12】 【Chemistry 13】 【Chemistry 14】 【Chemistry 15】 【Chemistry 16】 【Chemistry 17】 [Chemistry 18] 【Chemistry 19】 【Chemistry 20】 【Chemistry 21】 【Chemistry 22】 【Chemistry 23】 【Chemistry 24】 【Chemistry 25】 【Chemistry 26】 【Chemistry 27】 【Chemistry 28】

9. The lithium salts include LiCl, LiBr, LiI, and LiBF. ４ , LiClO ４ , LiAlO ４ , LiAlCl ４ , LiPF ６ , LiSbF ６ , LiAsF ６ , LiB １０ Cl １０ , LiBOB(LiB(C ２ O ４ ) ２ ), LiCF ３ SO ３ , LiFSI(LiN(SO ２ F) ２ ), LiCH ３ SO ３ , LiCF ３ CO ２ , LiCH ３ CO ２ , and LiBETI(LiN(SO ２ CF ２ CF ３ ) ２ 2. The lithium secondary battery according to claim 1, comprising at least one selected from the group consisting of:

10. 2. The lithium secondary battery according to claim 1, wherein the lithium salt is contained in the non-aqueous electrolyte at a molar concentration of 0.5 M to 5.0 M.

11. 2. The lithium secondary battery according to claim 1, wherein the organic solvent includes at least one selected from the group consisting of a cyclic carbonate organic solvent, a linear carbonate organic solvent, a linear ester organic solvent, and a cyclic ester organic solvent.

12. placing an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode in a battery case; and injecting a non-aqueous electrolyte into the battery case containing the electrode assembly. the positive electrode includes a positive electrode active material, The positive electrode active material includes a lithium transition metal oxide represented by the following chemical formula X: the non-aqueous electrolyte contains a lithium salt, an organic solvent, and an additive; the additives include a first additive and a second additive; the first additive comprises a phosphate-based additive containing a silyl group; The second additive comprises a compound represented by the following Chemical Formula 1: [Chemical formula X] Li １＋ｘ [Ni ａ Co ｂ Mn ｃ M １ ｄ ]O ２＋ｗ (wherein in the chemical formula X, 0≦x≦0.5, a+b+c+d=1, 0.5≦a≦0.7, 0≦b≦0.15, c=1−a−b−d, 0≦d≦0.1, 0≦b / a≦0.2, 1≦a / c≦3, 0≦w≦1, M １ is one or more selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo. [Chemical formula 1] 【Chemistry 29】 In the above Chemical Formula 1, n is 1 or 2; L １ and L ２ are each independently a direct bond or a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, R １ and R ２ are each independently a substituent represented by the following chemical formula 2: [Chemical formula 2] 【Transformation 30】 In the above Chemical Formula 2, m is 1 or 2; X １ and X ２ are each independently —O— or —C(R ３１ ) (R ３２ )-, wherein said X １ and X ２ at least one of is —O—; R ３１ ~R ３６ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or —C(═O)—R ４ , or -R ５ -OC(=O)-R ６ and The R ４ and R ６ each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, The R ５ is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, Said L １ , L ２ , R ４ , R ５ , and R ６ The substituents are each independently deuterium, —F, —Cl, —Br, —I, —CN, or —NO ２ , and -SO ３ and one or more selected from the group consisting of: * indicates L １ or L ２ At the position where it binds to L １ and L ２ When both of R １ and R ２ At the same time, it is not the CS-7 below, L １ and L ２ are methylene groups and n is 2, １ and R ２ At the same time, it is not CS-2 below.) 【Chemistry 31】

13. 13. The method for producing a lithium secondary battery according to claim 12, wherein the first additive is tris(trimethylsilyl)phosphate.

14. 13. The method for manufacturing a lithium secondary battery according to claim 12, wherein the first additive is contained in the non-aqueous electrolyte in an amount of 0.01% by weight to 10% by weight.

15. 13. The method for manufacturing a lithium secondary battery according to claim 12, wherein the second additive is contained in the non-aqueous electrolyte in an amount of 0.01% by weight to 10% by weight.

16. The R １ and R ２ are each independently selected from the group consisting of the following CS-1 to CS-15, the method for producing a lithium secondary battery according to claim 12: 【Chemistry 32】 【Transformation 33】 【Transformation 34】 【Chemistry 35】 【Transformation 36】 【Chemistry 37】 【Transformation 38】

17. The R １ and R ２ are each independently any one selected from the group consisting of CS-1, CS-2, CS-5, CS-8, CS-10, and CS-11.

18. Said L １ and L ２ The method for producing a lithium secondary battery according to claim 12 , wherein is a methylene group.

19. 13. The method of claim 12, wherein the compound represented by Chemical Formula 1 is any one selected from the group consisting of the following compounds A to R: 【Chemistry 39】 【Chemistry 40】 【Chemistry 41】 【Chemistry 42】 【Chemistry 43】 【Chemistry 44】 【Chemistry 45】 【Chemistry 46】 【Chemistry 47】 【Chemistry 48】 【Chemistry 49】 [Transformation 50] 【Chemistry 51】 【Chemistry 52】 【Chemistry 53】 【Chemistry 54】 【Transformation 55】 【Transformation 56】

20. The lithium salts include LiCl, LiBr, LiI, and LiBF. ４ , LiClO ４ , LiAlO ４ , LiAlCl ４ , LiPF ６ , LiSbF ６ , LiAsF ６ , LiB １０ Cl １０ , LiBOB(LiB(C ２ O ４ ) ２ ), LiCF ３ SO ３ , LiFSI(LiN(SO ２ F) ２ ), LiCH ３ SO ３ , LiCF ３ CO ２ , LiCH ３ CO ２ , and LiBETI(LiN(SO ２ CF ２ CF ３ ) ２ 13. The method for producing a lithium secondary battery according to claim 12, wherein the lithium secondary battery comprises at least one selected from the group consisting of:

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