NOVEL ADDITIVE FOR NON-AQUEOUS ELECTROLYTE SOLUTION AND LITHIUM SECONDARY BATTERY CONTAINING SAME

Abstract

The present invention relates to a novel additive for a non-aqueous electrolyte solution and a lithium secondary battery containing the same. The additive for a non-aqueous electrolyte solution contains an ionic compound represented by Chemical Formula 1, and by forming a coating on the surface of an electrode during activation of the secondary battery, it is possible to prevent the generation of a large amount of gas under high temperature conditions, and to prevent a drop in OCV and a decrease in capacity retention rate of the cell due to elution of metal ions from the electrode, thereby effectively improving the durability, performance, and high-temperature safety of the battery.

Description

[Technical field]

[0001] The present invention relates to a novel additive for a non-aqueous electrolyte solution and a lithium secondary battery containing the same.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0157227 dated November 16, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference. [Background technology]

[0003] In recent years, secondary batteries have been widely used not only in small devices such as portable electronic devices, but also in medium- to large-sized devices such as battery packs for hybrid and electric vehicles and power storage devices. Examples of such secondary batteries include non-aqueous electrolyte batteries such as lithium ion batteries, lithium batteries, lithium ion capacitors, and sodium ion batteries.

[0004] Among such non-aqueous electrolyte batteries, lithium ion batteries are used by injecting an electrolyte into a battery cell including a positive electrode containing a positive electrode active material capable of intercalating and deintercalating lithium, and a negative electrode containing a negative electrode active material capable of intercalating and deintercalating lithium. In particular, the electrolyte uses an organic solvent in which a lithium salt is dissolved, and is important in determining the stability and performance of a lithium secondary battery.

[0005] For example, LiPF, which is the most commonly used lithium salt in electrolytes, 6 reacts with the electrolyte solvent to accelerate the depletion of the solvent and generate HF. The generated HF not only generates a large amount of gas under high temperature conditions, but also dissolves metal ions. If the dissolved metal ions are generated in the form of deposition on the surface of the negative electrode, they cause an increase in the negative electrode potential and a drop in the OCV of the cell, which reduces not only the performance of the battery but also its lifespan and high-temperature safety. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the object of the present invention is to form a coating on the surface of the electrode to prevent direct contact between the positive electrode and the electrolyte, and to prevent the positive electrode from contacting with HF, PF, etc. 5 and the like, while preventing direct contact therewith, reducing oxidative decomposition of the electrolyte, suppressing gas generation, improving the phenomenon of metal ion deposition from the positive electrode, improving the capacity retention rate, and at the same time, developing a technology capable of preventing a drop in the OCV of a battery. [Means for solving the problem]

[0007] In order to solve the above problems, in one embodiment, the present invention provides an additive for an electrolyte for a secondary battery, comprising a compound represented by the following Chemical Formula 1:

[0008] [ka]

[0009] In the above formula 1, R 1 represents an oxygen atom, a nitrogen atom, a sulfur atom, an arylene group having 6 to 10 carbon atoms, a heteroarylene group having 5 to 10 carbon atoms and containing one or more of N, O, and S, and [ka] Includes one or more of the following: R 2 is a fluoro group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or [ka] And the above [ka] and [ka] one or more of the hydrogen atoms contained in may be substituted with a fluorine atom, M includes one or more selected from the group consisting of lithium, sodium, potassium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms, l is an integer of 1 to 6, and m and n are each an integer of 2 to 20.

[0010] Specifically, the above R 1 is a phenylenyl group, a naphthalenyl group, a pyrrolinyl group, a furanyl group, a thiophenyl group, an imidazolinyl group, [ka] and [ka] Includes one or more of the following: R 2 is a fluoro group, a methyl group, an ethyl group, a propyl group, a methoxy group, an ethoxy group, [ka] or [ka] where M is lithium, l is an integer of 1 or 2, and m and n can each be an integer from 2 to 10.

[0011] More specifically, the compound represented by Chemical Formula 1 above may be one or more of the compounds represented by the following <Structural Formula 1> to <Structural Formula 35>. [Table 1] [Table 2] [Table 3]

[0012] In one embodiment, the present invention provides an electrolyte composition for a lithium secondary battery, the electrolyte composition comprising a non-aqueous organic solvent, a lithium salt, and a compound represented by the following Chemical Formula 1:

[0013] [ka]

[0014] In the above formula 1, R 1 represents an oxygen atom, a nitrogen atom, a sulfur atom, an arylene group having 6 to 10 carbon atoms, a heteroarylene group having 5 to 10 carbon atoms and containing one or more of N, O, and S, and [ka] Includes one or more of the following: R 2 is a fluoro group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or [ka] And the above [ka] and [ka] one or more of the hydrogen atoms contained in may be substituted with a fluorine atom, M includes one or more selected from the group consisting of lithium, sodium, potassium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms, l is an integer of 1 to 6, and m and n are each an integer of 2 to 20.

[0015] In this case, the compound represented by Chemical Formula 1 may be included in an amount of 0.01 to 3 wt % based on the total weight of the electrolyte composition.

[0016] The lithium salts are LiCl, LiBr, LiI, and LiClO. 4 , LiBF 4 , LiB10Cl 10 , LiPF6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , C.H. 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi and (FSO 2 ) 2 NLi may include one or more selected from the group consisting of

[0017] Furthermore, the non-aqueous organic solvent may include N-methyl-2-pyrrolidinone, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate and ethyl propionate.

[0018] Further, in one embodiment, the present invention provides a lithium secondary battery including an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, the positive electrode and the negative electrode including at least one positive electrode active material selected from the lithium metal oxides represented by the following Chemical Formula 2 and Chemical Formula 3, and the electrolyte solution composition according to the present invention.

[0019] [Chemical formula 2] Li x [Ni y Co z Mn w M 1 v ]O 2

[0020] [Chemical formula 3] LiM 2 p Mn (2-p) O 4

[0021] In the above Chemical Formula 2 and Chemical Formula 3, M 1 is one or more elements selected from the group consisting of 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, and x, y, z, w, and v are 1.0≦x≦1.30, 0.5≦y<1, 0 <z≦0.3、0<w≦0.3、0≦v≦0.1であり、y+z+w+v=1であり、M 2 is Ni, Co or Fe, and p is 0.05≦p≦0.6.

[0022] At this time, the positive electrode active material is LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.9 Co 0.05 Mn 0.05 O 2 , LiNi 0.6 Co 0.2 Mn 0.1 Al 0.1 O 2 , LiNi 0.6 Co 0.2 Mn 0.15 Al 0.05 O 2 , LiNi 0.7 Co 0.1 Mn 0.1 Al 0.1 O 2 and LiNi 0.5 Mn 1.5 O 4 The composition may include one or more selected from the group consisting of:

[0023] The negative electrode active material is composed of a carbon material and a silicon material, and the silicon material is silicon (Si), silicon carbide (SiC), and silicon oxide (SiO q , where 0.8≦q≦2.5) may be included.

[0024] The silicon material may be included in an amount of 1 to 20 wt % based on the total weight of the negative electrode active material. Effect of the Invention

[0025] The electrolyte additive according to the present invention can prevent a large amount of gas from being generated under high temperature conditions by forming a coating on the surface of the electrode during activation of the secondary battery, and can prevent a drop in the OCV and a decrease in the capacity retention rate of the cell caused by the elution of metal ions from the electrode, thereby effectively improving the durability, performance, and high temperature safety of the battery. [Brief description of the drawings]

[0026] [Figure 1] 1 is a graph showing the results of Raman spectroscopy of electrolyte compositions prepared in Example 1 according to the present invention and Comparative Example 1. [Diagram 2] 1 is a graph showing the analysis results of differential capacity curves for half cells including electrolyte solutions prepared in Example 1 and Comparative Example 1 according to the present invention. [Diagram 3] 1 is a graph showing analysis results of a three-electrode battery including electrolyte compositions prepared in Example 1 and Comparative Example 1 according to the present invention using a linear scanning potential method. [Figure 4] 1 is a graph showing the results of X-ray photoelectron spectroscopy analysis of coatings formed on the surfaces of positive and negative electrodes of lithium secondary batteries after charging and discharging the batteries containing the electrolyte solution compositions prepared in Example 9, Comparative Example 15, and Comparative Example 19 according to the present invention. [Diagram 5]1 is a graph showing the results of X-ray photoelectron spectroscopy analysis of coatings formed on the surfaces of positive and negative electrodes of lithium secondary batteries after charging and discharging the batteries containing the electrolyte solution compositions prepared in Example 9, Comparative Example 15, and Comparative Example 19 according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The present invention is susceptible to various modifications and may have various embodiments, and therefore, specific embodiments are described in detail in the detailed description.

[0028] However, this is not intended to limit the invention to the particular embodiment, but should be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the present invention.

[0029] In the present invention, terms such as "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but should be understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0030] In addition, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion in between. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion in between. In addition, in the present application, being "on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0031] In addition, in the present invention, "including as a main component" may mean including 50 wt% or more, 60 wt% or more, 70 wt% or more, 80 wt% or more, 90 wt% or more, or 95 wt% or more of the defined component based on the total weight. For example, "including graphite as a main component as a negative electrode active material" may mean including 50 wt% or more, 60 wt% or more, 70 wt% or more, 80 wt% or more, 90 wt% or more, or 95 wt% or more of graphite based on the total weight of the negative electrode active material, and in some cases, may mean that the entire negative electrode active material is made of graphite and includes 100 wt% of graphite.

[0032] The present invention will now be described in more detail.

[0033] <Electrolyte additives for secondary batteries> In one embodiment, the present invention provides an additive for an electrolyte solution for a secondary battery, comprising a compound represented by the following Chemical Formula 1:

[0034] [ka]

[0035] In the above formula 1, R 1 represents an oxygen atom, a nitrogen atom, a sulfur atom, an arylene group having 6 to 10 carbon atoms, a heteroarylene group having 5 to 10 carbon atoms and containing one or more of N, O, and S, and [ka] Includes one or more of the following: R 2 is a fluoro group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or [ka] And the above [ka] and [ka] one or more of the hydrogen atoms contained in may be substituted with a fluorine atom, M includes one or more selected from the group consisting of lithium, sodium, potassium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms, l is an integer of 1 to 6, and m and n are each an integer of 2 to 20.

[0036] The electrolyte additive for secondary batteries according to the present invention includes an ionic compound having a mother nucleus in which a vinyl group is bound to one side of a sulfonylimide group through a functional group that extends the conjugation of the sulfonylimide group or a functional group having a polyglycol unit, as shown in Chemical Formula 1. The compound has a vinyl group bound to one side of the sulfonylimide group to form a conjugated bond or through a polyglycol unit, and has a structure having a charge in the molecule, so that an organic and / or inorganic coating can be uniformly formed on the surface of the positive electrode and / or negative electrode when a secondary battery including the compound is activated. That is, the electrolyte additive can be directly contained in a monomolecular form in the organic and / or inorganic coating formed on the surface of the positive electrode and / or negative electrode when the secondary battery is activated, thereby suppressing the decomposition of the electrolyte and the generation of gas when the battery is exposed to high temperatures, and improving the OCV drop of the battery generated at the positive electrode.

[0037] For this purpose, in the compound represented by the above formula 1, R 1 represents an oxygen atom, a nitrogen atom, a sulfur atom, a phenylenyl group, a naphthalenyl group, an anthracenyl group, a furanyl group, a thiophenyl group, a pyrrolinyl group, an imidazolinyl group, a pyridinyl group, and [ka] Includes one or more of the following: R 2 is a fluoro group, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, or [ka] And the above [ka] and [ka] one or more of the hydrogen atoms contained in may be substituted with a fluorine atom, M includes one or more selected from the group consisting of lithium, sodium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms, l is an integer of 1 to 6, and m and n are each an integer of 2 to 20.

[0038] Specifically, R 1 is a phenylenyl group, a naphthalenyl group, a pyrrolinyl group, a furanyl group, a thiophenyl group, an imidazolinyl group, [ka] and [ka] Includes one or more of the following: R 2 is a fluoro group, a methyl group, an ethyl group, a propyl group, a methoxy group, an ethoxy group, [ka] or [ka] where M is lithium, l is an integer of 1 or 2, and m and n can each be an integer from 2 to 10.

[0039] As an example, the compound represented by Chemical Formula 1 above may be one or more of the compounds represented by the following <Structural Formula 1> to <Structural Formula 35>. [Table 4] [Table 5] [Table 6]

[0040] In the above <Structural Formula 7> and <Structural Formulas 14> to <Structural Formulas 28>, a is an integer of 2 to 5.

[0041] As described above, the electrolyte additive according to the present invention has a vinyl group bonded to one side of a sulfonylimide group through a functional group that extends the conjugation of the sulfonylimide group or a functional group having a polyglycol unit, and has a structure having a charge within the molecule. Therefore, during activation of the battery, the additive can directly participate in the solvation shell of lithium ions even at low potentials, and can uniformly form a negative charge and / or an inorganic coating on the surface of the negative electrode through a reduction reaction, and can simultaneously uniformly form an inorganic coating on the surface of the positive electrode through an oxidation reaction.

[0042] As a result, the electrolyte additive can suppress the decomposition of the electrolyte and the generation of gas when the battery is exposed to high temperatures, while improving the decrease in OCV of the battery that occurs at the positive electrode, thereby preventing deterioration of the secondary battery and further improving high temperature safety.

[0043] <Electrolyte composition for lithium secondary batteries> In one embodiment, the present invention provides an electrolyte composition for a lithium secondary battery, the electrolyte composition comprising a non-aqueous organic solvent, a lithium salt, and a compound represented by the following Chemical Formula 1:

[0044] [ka]

[0045] In the above Chemical Formula 1, R 1 represents an oxygen atom, a nitrogen atom, a sulfur atom, an arylene group having 6 to 10 carbon atoms, a heteroarylene group having 5 to 10 carbon atoms and containing one or more of N, O, and S, and [ka] Includes one or more of the following: R 2 is a fluoro group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or [ka] And the above [ka] and [ka] one or more of the hydrogen atoms contained in may be substituted with a fluorine atom, M includes one or more selected from the group consisting of lithium, sodium, potassium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms, l is an integer of 1 to 6, and m and n are each an integer of 2 to 20.

[0046] The electrolyte composition for a lithium secondary battery according to the present invention may be a non-aqueous electrolyte composition, which is a liquid electrolyte having a configuration including a lithium salt and an electrolyte additive in a non-aqueous organic solvent. Here, the electrolyte composition includes the electrolyte additive of the present invention described above, which includes a compound represented by Chemical Formula 1, as an electrolyte additive, and may directly participate in the solvation shell of lithium ions during activation of a battery including the electrolyte additive, thereby uniformly forming a negatively charged and / or inorganic coating on the surface of the negative electrode through a reduction reaction.

[0047] For this purpose, in the compound represented by the above formula 1, R 1 represents an oxygen atom, a nitrogen atom, a sulfur atom, a phenylenyl group, a naphthalenyl group, an anthracenyl group, a furanyl group, a thiophenyl group, a pyrrolinyl group, an imidazolinyl group, a pyridinyl group, and [ka] Includes one or more of the following: R 2 is a fluoro group, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, or [ka] And the above [ka] and [ka] one or more of the hydrogen atoms contained in may be substituted with a fluorine atom, M includes one or more selected from the group consisting of lithium, sodium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms, l is an integer of 1 to 6, and m and n are each an integer of 2 to 20.

[0048] Specifically, R 1 is a phenylene group, a naphthalenyl group, a pyrrolinyl group, a furanyl group, a thiophenyl group, an imidazolinyl group, [ka] and [ka] Includes one or more of the following: R 2 is a fluoro group, a methyl group, an ethyl group, a propyl group, a methoxy group, an ethoxy group, [ka] or [ka] where M is lithium, l is an integer of 1 or 2, and m and n can each be an integer from 2 to 10.

[0049] In addition, the compound represented by the above formula 1 may be included in the electrolyte composition at a specific content. Specifically, the compound represented by the above formula 1 may be included in the electrolyte composition at 0.01 to 5 wt %, more specifically, at 0.05 to 3 wt % or 1.0 to 2.5 wt % based on the total weight of the electrolyte composition. The present invention prevents the electrolyte additive from being used in an excessive amount exceeding the above range, thereby increasing the viscosity of the electrolyte composition and decreasing the wettability to the electrodes and the separator, and prevents the electrolyte additive from being polymerized due to self-polymerization in the electrolyte composition during activation, thereby reducing the ion conductivity of the electrolyte composition and decreasing the performance of the battery. In addition, the present invention prevents the electrolyte additive from being used in a small amount outside the above range, resulting in only a slight effect of the additive.

[0050] Meanwhile, the lithium salt used in the electrolyte composition may be any salt used in non-aqueous electrolytes in the art without any particular limitation. Specifically, the lithium salt may be LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB10Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , C.H. 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi and (FSO 2 ) 2 NLi may include one or more selected from the group consisting of

[0051] The concentration of these lithium salts is not particularly limited, but the lower limit of the preferred concentration range is 0.5 mol / L or more, specifically 0.7 mol / L or more, more specifically 0.9 mol / L or more, and the upper limit is 2.5 mol / L or less, specifically 2.0 mol / L or less, more specifically 1.5 mol / L or less. If the concentration of the lithium salt is below 0.5 mol / L, the ionic conductivity is reduced, which may reduce the cycle characteristics and output characteristics of the nonaqueous electrolyte battery. If the concentration of the lithium salt is above 2.5 mol / L, the viscosity of the electrolyte for the nonaqueous electrolyte battery increases, which may also reduce the ionic conductivity, which may reduce the cycle characteristics and output characteristics of the nonaqueous electrolyte battery.

[0052] In addition, when a large amount of lithium salt is dissolved in a non-aqueous organic solvent at once, the liquid temperature may rise due to the heat of dissolution of the lithium salt. If the temperature of the non-aqueous organic solvent rises significantly due to the heat of dissolution of the lithium salt, in the case of a lithium salt containing fluorine, decomposition may be promoted and hydrogen fluoride (HF) may be generated. Hydrogen fluoride (HF) is undesirable because it causes deterioration of battery performance. Therefore, the temperature when dissolving the lithium salt in the non-aqueous organic solvent is not particularly limited, but may be adjusted to -20 to 80°C, specifically 0 to 60°C.

[0053] In addition, the non-aqueous organic solvent used in the electrolyte composition may be applied without any particular limitation as long as it is used in the art for non-aqueous electrolytes.Specifically, the non-aqueous organic solvent may be, for example, aprotic organic solvents such as N-methyl-2-pyrrolidinone, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ether, methyl propionate, and ethyl propionate.

[0054] The non-aqueous solvent used in the present invention may be one type alone, or two or more types may be mixed in any combination and ratio according to the purpose. Among these, propylene carbonate, ethylene carbonate, fluoroethylene carbonate, diethyl carbonate, dimethyl carbonate, and ethyl methyl carbonate are particularly preferred from the viewpoints of electrochemical stability against oxidation and reduction and chemical stability against heat and reaction with solutes.

[0055] On the other hand, the electrolyte composition may further contain additives in addition to the basic components described above. As long as the gist of the present invention is not impaired, additives generally used in the nonaqueous electrolyte of the present invention may be added at any ratio. Specifically, compounds having an overcharge prevention effect, an anode film formation effect, and a cathode protection effect, such as cyclohexylbenzene, biphenyl, t-butylbenzene, vinylene carbonate, vinylethylene carbonate, difluoroanisole, fluoroethylene carbonate, propane sultone, succinonitrile, and dimethylvinylene carbonate, may be mentioned. In addition, as in the case of use in a nonaqueous electrolyte battery called a lithium polymer battery, it is also possible to use the electrolyte for a nonaqueous electrolyte battery by solidifying it with a gelling agent or a crosslinked polymer.

[0056] <Lithium secondary battery> Further, in one embodiment, the present invention provides a lithium secondary battery including an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, the positive electrode and the negative electrode including at least one positive electrode active material selected from the lithium metal oxides represented by the following Chemical Formula 2 and Chemical Formula 3, and the electrolyte solution composition according to the present invention.

[0057] [Chemical formula 2] Li x [Ni y Co z Mn w M 1 v ]O 2

[0058] [Chemical formula 3] LiM 2 p Mn (2-p) O 4

[0059] In the above Chemical Formula 2 and Chemical Formula 3, M 1is one or more elements selected from the group consisting of 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, and x, y, z, w, and v are 1.0≦x≦1.30, 0.5≦y<1, 0 <z≦0.3、0<w≦0.3、0≦v≦0.1であり、y+z+w+v=1であり、M 2 is Ni, Co or Fe, and p is 0.05≦p≦0.6.

[0060] The lithium secondary battery according to the present invention includes a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, a separator interposed between the positive electrode and the negative electrode, and the nonaqueous electrolyte composition containing the lithium salt of the present invention described above.

[0061] Specifically, the positive electrode includes a positive electrode mixture layer produced by applying a positive electrode active material onto a positive electrode current collector, drying and pressing the positive electrode mixture layer, and may further include a conductive material, a binder, other additives, and the like as necessary.

[0062] Here, the positive electrode active material is a material that can undergo an electrochemical reaction on a positive electrode current collector, and may include at least one of the lithium metal oxides represented by Chemical Formula 2 and Chemical Formula 3 that are capable of reversibly intercalating and deintercalating lithium ions.

[0063] The lithium metal oxides represented by Chemical Formula 2 and Chemical Formula 3 are materials containing high amounts of nickel (Ni) and manganese (Mn), respectively, and have the advantage of being able to stably supply high-capacity and / or high-voltage electricity when used as positive electrode active materials. In addition, a high charging potential of about 4.0 V or more is required to form a coating on the surface of the positive electrode and / or negative electrode during activation of a secondary battery. Unlike conventional positive electrode active materials such as iron phosphate, which have a charging potential of less than 4.0 V, the lithium metal oxides have a high charging potential of about 4.0 V or more, making it easy to form a coating on the electrode.

[0064] In this case, the lithium metal oxide represented by the above chemical formula 2 is LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.9 Co 0.05 Mn 0.05 O 2 , LiNi 0.6 Co 0.2 Mn 0.1 Al 0.1 O 2 , LiNi 0.6 Co 0.2 Mn 0.15 Al 0.05 O 2 , LiNi 0.7 Co 0.1 Mn 0.1 Al 0.1 O 2 The lithium metal oxide represented by the above formula 2 may include LiNi 0.7 Mn 1.3 O 4 , LiNi 0.5 Mn 1.5 O 4 , LiNi 0.3 Mn 1.7 O 4 etc., which may be used alone or in combination.

[0065] In addition, the positive electrode may use a positive electrode current collector having high conductivity without inducing chemical changes in the battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, etc. may be used, and in the case of aluminum or stainless steel, those surface-treated with carbon, nickel, titanium, silver, etc. may also be used. Furthermore, the average thickness of the current collector may be suitably applied to be 3 to 500 μm, taking into consideration the conductivity and total thickness of the positive electrode to be manufactured.

[0066] Similarly to the positive electrode, the negative electrode includes a negative electrode mixture layer produced by applying a negative electrode active material onto a negative electrode current collector, drying and pressing the negative electrode active material, and may further include a conductive material, a binder, other additives, and the like as necessary.

[0067] The negative electrode active material may include a carbon material and a silicon material. Specifically, the carbon material means a material mainly composed of carbon atoms, and such a carbon material may include at least one material selected from the group consisting of natural graphite, artificial graphite, expanded graphite, non-graphitizable carbon, carbon black, acetylene black, and ketjen black. The silicon material means a material mainly composed of silicon atoms, and such a silicon material may include silicon (Si), silicon carbide (SiC), silicon monoxide (SiO), or silicon dioxide (SiO 2 ) may be used alone or in combination. The silicon (Si)-containing material may be silicon monoxide (SiO) or silicon dioxide (SiO 2 ) are mixed uniformly or composited and included in the negative electrode mixture layer, they are considered to be silicon oxide (SiO q , where 0.8≦q≦2.5).

[0068] The silicon material may be contained in an amount of 1 to 20 wt % based on the total weight of the negative electrode active material, specifically, 3 to 10 wt %, 8 to 15 wt %, 13 to 18 wt %, or 2 to 8 wt %. The present invention can maximize the energy density of the battery by adjusting the content of the silicon material within the above content range.

[0069] The negative electrode current collector is not particularly limited as long as it has high conductivity without inducing chemical changes in the battery, and may be, for example, copper, stainless steel, nickel, titanium, calcined carbon, etc. In the case of copper or stainless steel, it may be surface-treated with carbon, nickel, titanium, silver, etc. The average thickness of the negative electrode current collector may be suitably 1 to 500 μm, taking into consideration the conductivity and total thickness of the negative electrode to be manufactured.

[0070] Meanwhile, the separator interposed between the positive and negative electrodes of each unit cell is an insulating thin film having high ion permeability and mechanical strength, and is not particularly limited as long as it is one commonly used in the art, specifically, one containing at least one polymer selected from polypropylene, polyethylene, and polyethylene-propylene copolymers having chemical resistance and hydrophobicity may be used. The separator may have the form of a porous polymer substrate such as a sheet or nonwoven fabric containing the above-mentioned polymer, and in some cases, may have the form of a composite separator in which organic or inorganic particles are coated on the porous polymer substrate with an organic binder. The separator may have an average pore diameter of 0.01 to 10 μm and an average thickness of 5 to 300 μm.

[0071] Furthermore, the secondary battery contains the above-mentioned nonaqueous electrolyte composition according to the present invention as an electrolyte.

[0072] The electrolyte composition includes, as an electrolyte additive, an ionic compound represented by the following Chemical Formula 1 having a mother nucleus in which a vinyl group is bonded to one side of a sulfonylimide group through a functional group that extends the conjugation of the sulfonylimide group or a functional group having a polyglycol unit.

[0073] [ka]

[0074] In the above formula 1, R 1 represents an oxygen atom, a nitrogen atom, a sulfur atom, an arylene group having 6 to 10 carbon atoms, a heteroarylene group having 5 to 10 carbon atoms and containing one or more of N, O, and S, and [ka] Includes one or more of the following: R 2 is a fluoro group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or [ka] And the above [ka] and [ka] one or more of the hydrogen atoms contained in may be substituted with a fluorine atom, M includes one or more selected from the group consisting of lithium, sodium, potassium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms, l is an integer of 1 to 6, and m and n are each an integer of 2 to 20.

[0075] The compound has a structure in which a vinyl group is conjugated to one side of a sulfonylimide or is bound via a polyglycol unit, and has a charge in the molecule, and thus can uniformly form an organic and / or inorganic coating on the surface of the positive electrode and / or negative electrode when a secondary battery containing the compound is activated. As a result, the electrolyte additive can suppress the decomposition of the electrolyte and the generation of gas when the battery is exposed to high temperatures, and can improve the OCV drop phenomenon of the battery generated at the positive electrode, thereby further improving the performance and high temperature safety of the battery.

[0076] For this purpose, in the compound represented by the above formula 1, R 1 represents an oxygen atom, a nitrogen atom, a sulfur atom, a phenylenyl group, a naphthalenyl group, an anthracenyl group, a furanyl group, a thiophenyl group, a pyrrolinyl group, an imidazolinyl group, a pyridinyl group, and [ka] Includes one or more of the following: R 2 is a fluoro group, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, or [ka] And the above [ka] and [ka] one or more of the hydrogen atoms contained in may be substituted with a fluorine atom, M includes one or more selected from the group consisting of lithium, sodium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms, l is an integer of 1 to 6, and m and n are each an integer of 2 to 20.

[0077] Specifically, R 1 is a phenylene group, a naphthalenyl group, a pyrrolinyl group, a furanyl group, a thiophenyl group, an imidazolinyl group, [ka] and [ka] Includes one or more of the following: R 2 is a fluoro group, a methyl group, an ethyl group, a propyl group, a methoxy group, an ethoxy group, [ka] or [ka] where M is lithium, l is an integer of 1 or 2, and m and n can each be an integer from 2 to 10.

[0078] As an example, the compound represented by Chemical Formula 1 above may be one or more of the compounds represented by the following <Structural Formula 1> to <Structural Formula 35>. [Table 7] [Table 8] [Table 9]

[0079] In the above <Structural Formula 7> and <Structural Formulas 14> to <Structural Formulas 28>, a is an integer of 2 to 5.

[0080] The present invention will now be described in more detail with reference to examples and experimental examples.

[0081] However, the following examples and experimental examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0082] <Examples 1 to 4 and Comparative Examples 1 to 6. Preparation of electrolyte composition for lithium secondary batteries> LiPF as a lithium salt was added to a solvent containing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7. 6 was dissolved at a concentration of 1 M, and additives as shown in Table 1 below were dissolved therein at 2 wt % based on the total weight of the electrolyte to prepare nonaqueous electrolyte compositions.

[0083] [Table 10A] [Table 10B]

[0084] <Comparative Example 7. Production of electrolyte composition for lithium secondary battery> A non-aqueous electrolyte composition for a lithium secondary battery was prepared by the same method as in Example 1, except that an oligomer (weight average molecular weight: 2,500 to 5,000) obtained by polymerizing a compound represented by Structural Formula 8 was used instead of the compound represented by Structural Formula 8 as an electrolyte additive.

[0085] <Examples 5 to 8 and Comparative Examples 8 to 14. Production of Lithium Secondary Batteries> The positive electrode active material is LiNi with a particle size of 5 μm. 0.5 Mn 1.5 O 4The above was prepared and mixed with a carbon-based conductive agent and polyvinylidene fluoride as a binder in a weight ratio of 94:3:3 in N-methylpyrrolidone (NMP) to form a slurry, which was then cast onto an aluminum sheet, dried in a vacuum oven at 120°C, and rolled to produce a positive electrode.

[0086] In addition to this, artificial graphite and silicon oxide (SiO 2 ) was mixed in a weight ratio of 9:1 to prepare a negative electrode active material, and 97 parts by weight of the negative electrode active material and 3 parts by weight of styrene-butadiene rubber (SBR) were mixed with water to form a slurry, which was then cast on a copper sheet, dried in a vacuum oven at 130°C, and rolled to produce a negative electrode.

[0087] The positive and negative electrodes obtained above were inserted into a case with a separator made of 18 μm polypropylene therebetween, and then the electrolyte compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 7 were injected as shown in Table 2 below to prepare lithium secondary batteries.

[0088] [Table 11]

[0089] <Experimental Example 1> In order to analyze the form in which the electrolyte composition for a lithium secondary battery according to the present invention is present in a secondary battery, the following experiment was carried out on the electrolyte compositions prepared in Example 1 and Comparative Example 1.

[0090] a) Raman spectroscopy analysis For each electrolyte composition (5 ml), a 532 nm laser was used to measure the intensity of the liquid at 650 to 760 cm -1 The results of Raman spectroscopy were shown in Figure 1.

[0091] 1, the electrolyte composition of Example 1 containing the electrolyte additive represented by Chemical Formula 1 according to the present invention had a solubility of 743±1 cm compared to the electrolyte composition prepared in Comparative Example 1 containing no electrolyte additive. -1It was confirmed that the band intensity of the Raman spectrum increased near the negative charge of the sulfonylimide electrolyte additive, which is represented by Chemical Formula 1. This is because the negative charge of the nitrogen atom and the positive charge of the lithium ion (Li + ) is a phenomenon that appears when ionic substances form coordinate bonds, and means that an ionic compound is contained in the electrolyte composition of Example 1. In addition, the increase in band intensity as described above indicates that the ionic compound can cause a reduction reaction on the surface of the negative electrode.

[0092] b) Analysis of differential capacity curve of half cell A half-cell was prepared using lithium metal and graphite (a mixture of artificial graphite and natural graphite in a weight ratio of 9:1), and the electrolyte compositions prepared in Example 1 and Comparative Example 1 were injected into the half-cell. The half-cell was then charged at 25°C and 3.5±0.5V at a rate of 0.005C up to 0.05V, and the potential value (V) and capacity value (mAh) were measured, and the capacity value compared to the potential value was differentiated (dQ / dV) to determine the reduction potential value. The results are shown in Figure 2 below.

[0093] 2, it was confirmed that the electrolyte composition of the example containing the electrolyte additive represented by Formula 1 according to the present invention exhibited a downward peak at a voltage of about 1.30 V compared to lithium, unlike the electrolyte composition of the comparative example not containing an electrolyte additive. The downward peak means that a reduction reaction occurred on the surface of the graphite electrode, which is the negative electrode, and indicates that the electrolyte additive represented by Formula 1 contained in the electrolyte composition is converted into a coating material by a reduction reaction on the surface of the negative electrode at about 1.30 V compared to lithium.

[0094] C) Evaluation of three-electrode battery using the linear scanning potential method The electrolyte compositions prepared in Example 1 and Comparative Example 1 were injected into batteries including a platinum electrode, a platinum electrode, and a lithium metal electrode as three electrodes to prepare three-electrode batteries, and a linear scanning potential (LSV) analysis was performed on each of the prepared batteries. At this time, the linear scanning potential (LSV) analysis was performed under the conditions of an observation range of 3.0 to 6.0 V (based on lithium), a step voltage of 50 mV, and a measurement speed of 50 mV / s, and the results are shown in FIG.

[0095] 3, it can be seen that the electrolyte composition of the embodiment containing the electrolyte additive represented by Chemical Formula 1 according to the present invention increases the current at about 4.03 V compared to lithium. This means that an oxidation reaction occurs on the surface of lithium metal at about 4.03 V, and indicates that the electrolyte additive contained in the electrolyte composition of Example 1 forms a film by oxidation on the surface of the positive electrode when the potential is 4.03 V or higher compared to lithium. In addition, it indicates that the oxidation reaction is induced at a lower potential on the carbon electrode or positive electrode than on the surface of the platinum electrode due to the catalytic properties of carbon or transition metal.

[0096] From these results, it can be seen that the electrolyte additive according to the present invention, as an ionic substance, undergoes oxidation and reduction reactions at the positive and negative electrodes, respectively, during charging and discharging of the battery, thereby forming a coating on the surface of each electrode.

[0097] <Experimental Example 2> The following experiment was carried out to analyze the coating formed on the surface of the electrode during activation of the lithium secondary battery according to the present invention and to evaluate the high temperature safety of the lithium secondary battery. 0.6 Co 0.2 Mn 0.2 O 2 The secondary batteries of Examples 9 to 12 and Comparative Examples 15 to 21 were prepared in the same manner as in Examples 5 to 8 and Comparative Examples 8 to 14, except that they contained artificial graphite.

[0098] a) Analysis of the coating on the electrode surface For the secondary batteries of Example 9, Comparative Example 15, Comparative Example 19, and Comparative Example 21, the charge / discharge cycle was performed three times with a current density of 0.33 C / 0.33 C, a charge cut-off voltage of 4.2 V (NMC / graphite), and a discharge cut-off voltage of 2.5 V (NMC / graphite). X-ray photoelectron spectroscopy (XPS) was performed on the surfaces of the positive and negative electrodes of each battery in a fully discharged state. The results are shown in Figures 4 and 5.

[0099] 4 and 5, the secondary battery (Example 9) containing the electrolyte composition of Example 1 was shown to have peaks in the range of 280 to 300 eV, which indicates the bond energy between carbon and fluorine, in both the positive and negative electrodes when X-ray photoelectron spectroscopy (XPS) was performed on the electrode surfaces. Specifically, the positive and negative electrodes of the secondary battery had CF 3 The secondary battery using the electrolyte composition of Comparative Example 1 (Comparative Example 15) not containing an electrolyte additive, the secondary battery using the electrolyte composition of Comparative Example 5 (Comparative Example 19) and the secondary battery using the electrolyte composition of Comparative Example 7 (Comparative Example 21) showed a peak indicating the bond energy of the CF group in both the positive and negative electrodes, which means that the electrolyte additive represented by Chemical Formula 1 contained in the electrolyte composition participated in the formation of the coating film formed on the surfaces of the positive and negative electrodes. 3 It was confirmed that the bond energy peak derived from the group was not observed.

[0100] From these results, it can be seen that the electrolyte additive according to the present invention contains an ionic compound in a monomolecular form represented by Chemical Formula 1 having a mother nucleus in which a vinyl group is bonded to one side of a sulfonylimide group via a functional group that extends the conjugation of the sulfonylimide group or a functional group having a polyglycol unit, and thus can form a coating containing the same on the surface of the electrode when the secondary battery is activated.

[0101] B) Evaluation of high-temperature storage stability of secondary batteries Each secondary battery was stored at 60°C for 56 days, during which (i) the amount of gas generated in the secondary battery and (ii) the OCV of the secondary battery were observed over time, and (iii) the capacity retention rate before and after high-temperature storage was analyzed.

[0102] Specifically, each secondary battery was charged and discharged three times with a charge / discharge current density of 0.33C / 0.33C, a charge cut-off voltage of 4.2V (NMC / graphite), and a discharge cut-off voltage of 2.5V (NMC / graphite) to measure the battery capacity, and then the secondary battery was fully charged in CC / CV mode with a charge cut-off voltage of 4.2V at 0.33C and high-temperature storage was started. The high-temperature storage was carried out for a total of 56 days in a constant temperature chamber at 60°C. After 56 days, the OCV deviation (i.e., the degree of OCV drop) and capacity retention rate before and after storage were measured, and the volume of gas generated in the secondary battery after high-temperature storage was measured using Archimedes' principle. The results are shown in Table 3 below.

[0103] [Table 12A] [Table 12B]

[0104] As shown in Table 3, the secondary battery according to the embodiment including the compound represented by Chemical Formula 1 according to the present invention as an electrolyte additive, even when exposed to high temperature conditions, has a significantly reduced amount of gas generated due to the reduced decomposition of the electrolyte caused by the coating formed on the surfaces of the positive and negative electrodes, and thus reduces the OCV drop phenomenon generated at the positive electrode.

[0105] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art or those having ordinary knowledge in the art that the present invention can be modified and changed in various ways without departing from the spirit and technical scope of the present invention as set forth in the claims below.

[0106] Therefore, the technical scope of the present invention should not be limited to the contents described in the Summary of the Invention of the specification, but should be defined by the claims.

Claims

1. The compound includes a compound represented by the following chemical formula 1: 【Chemistry 1】 In the above Chemical Formula 1, R １ represents an arylene group having 6 to 10 carbon atoms, a heteroarylene group having 5 to 10 carbon atoms containing one or more of N, O, and S, and 【Chemistry 2】 Contains one or more of the following: R ２ is a fluoro group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or 【Chemistry 3】 and The above 【Chemistry 4】 and 【Chemistry 5】 One or more of the hydrogen atoms contained in may be replaced by a fluorine atom; M includes at least one selected from the group consisting of lithium, sodium, potassium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms; l is an integer from 1 to 6; wherein m and n are integers of 2 to 20.

2. R １ is a phenylenyl group, a naphthalenyl group, a pyrrolinyl group, a furanyl group, a thiophenyl group, an imidazolinyl group, 【Chemistry 6】 and 【Chemistry 7】 Contains one or more of the following: R ２ is a fluoro group, a trifluoromethyl group, a methyl group, an ethyl group, a propyl group, a methoxy group, an ethoxy group, 【Chemistry 8】 or 【Chemistry 9】 and M is lithium; l is an integer of 1 or 2; 2. The secondary battery electrolyte additive according to claim 1, wherein m and n are each an integer of 2 to 10.

3. The electrolyte additive for a secondary battery according to claim 1, wherein the compound represented by Chemical Formula 1 is at least one compound selected from the following <Structural Formula 1> to <Structural Formula 35>. 【Table 1】 【Table 2】 【Table 3】

4. An electrolyte composition for a lithium secondary battery comprising a non-aqueous organic solvent, a lithium salt, and a compound represented by the following Chemical Formula 1: 【Chemistry 10】 In the above Chemical Formula 1, R １ represents an arylene group having 6 to 10 carbon atoms, a heteroarylene group having 5 to 10 carbon atoms containing one or more of N, O, and S, and 【Chemistry 11】 Contains one or more of the following: R ２ is a fluoro group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or 【Chemistry 12】 and The above 【Chemistry 13】 and 【Chemistry 14】 One or more of the hydrogen atoms contained in may be replaced by a fluorine atom; M includes at least one selected from the group consisting of lithium, sodium, potassium, tetraalkylammonium having 1 to 4 carbon atoms, and tetraalkylphosphonium having 1 to 4 carbon atoms; l is an integer from 1 to 6; m and n are each an integer of 2 to 20.

5. 5. The electrolyte composition for a lithium secondary battery according to claim 4, wherein the compound represented by Chemical Formula 1 is contained in an amount of 0.01 to 3 wt % based on the total weight of the electrolyte composition.

6. Lithium salts include LiCl, LiBr, LiI, and LiClO. ４ , LiBF ４ , LiB １０ C １０ , LiPF ６ , LiCF ３ SO ３ , LiCF ３ CO ２ , LiAsF ６ , LiSbF ６ , LiAlCl ４ , C.H. ３ SO ３ Li, (CF ３ SO ２ ) ２ NLi and (FSO ２ ) ２ The electrolyte composition for a lithium secondary battery according to claim 4 , comprising at least one selected from the group consisting of NLi.

7. The non-aqueous organic solvent is selected from the group consisting of N-methyl-2-pyrrolidinone, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, and ethyl propionate. The electrolyte composition for lithium secondary batteries according to claim 4, which includes at least one selected from the group consisting of methyl propionate and ethyl propionate.

8. An electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, the positive electrode and the negative electrode including at least one positive electrode active material selected from the group consisting of lithium metal oxides represented by the following Chemical Formula 2 and Chemical Formula 3: The electrolyte composition according to any one of claims 4 to 7, [Chemical formula 2] Li ｘ [Ni ｙ Co ｚ Mn ｗ M １ ｖ ]O ２ [Chemical formula 3] LiM ２ ｐ Mn （２－ｐ） O ４ In the above Chemical Formula 2 and Chemical Formula 3, M １ is one or more elements selected from the group consisting of 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; x, y, z, w and v are each 1.0≦x≦1.30, 0.5≦y<1, 0<z≦0.3, 0<w≦0.3, 0≦v≦0.1, and y+z+w+v=1; M ２ is Ni, Co or Fe, A lithium secondary battery, wherein p is 0.05≦p≦0.

6.

9. The positive electrode active material is LiNi ０．８ Co ０．１ Mn ０．１ O ２ , LiNi ０．６ Co ０．２ Mn ０．２ O ２ , LiNi ０．９ Co ０．０５ Mn ０．０５ O ２ , LiNi ０．６ Co ０．２ Mn ０．１ A ０．１ O ２ , LiNi ０．６ Co ０．２ Mn ０．１５ A ０．０５ O ２ , LiNi ０．７ Co ０．１ Mn ０．１ A ０．１ O ２ and LiNi ０．５ Mn １．５ O ４ The lithium secondary battery according to claim 8, comprising one or more selected from the group consisting of:

10. The negative electrode active material is composed of a carbon material and a silicon material, The silicon materials include silicon (Si), silicon carbide (SiC) and silicon oxide (SiO ｑ The lithium secondary battery according to claim 8 , wherein q is selected from the group consisting of 0.8≦q≦2.

5.

11. The lithium secondary battery according to claim 10, wherein the silicon material is contained in an amount of 1 to 20% by weight based on the total weight of the negative electrode active material.

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