KR20220138764A - Non-aqueous electrolyte and lithium secondary battery comprising the same - Google Patents

Abstract

The present invention relates to a non-aqueous electrolyte and a lithium secondary battery including the same, wherein the non-aqueous electrolyte has metal ion adsorption performance, forms a stable solid electrolyte interphase (SEI) film on a positive electrode or a negative electrode at high temperature, and suppresses the elution of transition metal ions, thereby improving high-temperature storage characteristics and lifespan characteristics.

Description

Non-aqueous electrolyte and lithium secondary battery comprising same

The present invention relates to a non-aqueous electrolyte and a lithium secondary battery comprising the same, and more particularly, has a metal ion adsorption performance, forms a stable SEI (solid electrolyte interphase) film on a positive electrode or a negative electrode at a high temperature, and inhibits the elution of transition metal ions Accordingly, it relates to an electrolyte in which high-temperature storage characteristics and lifespan characteristics can be improved, and a lithium secondary battery including the same.

Recently, interest in energy storage technology is increasing, and as the field of application is expanded to energy of mobile phones, camcorders, notebook PCs, and even electric vehicles, efforts for research and development of electrochemical devices are becoming more concrete.

Among electrochemical devices, interest in the development of rechargeable batteries capable of charging and discharging is on the rise. In particular, lithium secondary batteries developed in the early 1990s are in the spotlight because of their high operating voltage and extremely high energy density.

Lithium secondary batteries generally form an electrode assembly by interposing a separator between a positive electrode including a positive electrode active material made of a transition metal oxide containing lithium, and a negative electrode including a negative electrode active material capable of storing lithium ions, and the electrode It is manufactured by inserting the assembly into the battery case, injecting a non-aqueous electrolyte serving as a medium for transferring lithium ions, and then sealing the assembly.

On the other hand, the lithium secondary battery has a problem in that the performance of the positive electrode is deteriorated as the positive electrode active material structurally collapses as charging and discharging proceed. In addition, transition metal ions eluted from the positive electrode are electrodeposited on the negative electrode to deteriorate the performance of the negative electrode, and the deterioration of the performance of the lithium secondary battery tends to be accelerated when the voltage is increased or exposed to high temperature.

Accordingly, a method of adding compounds to prevent deterioration of the performance of the negative electrode has been proposed, but there is a problem in that the overall performance of the battery is deteriorated by the compound additive.

Therefore, it is required to develop a lithium secondary battery capable of suppressing the elution of transition metal ions by forming a stable SEI film on the positive electrode or negative electrode under high temperature conditions without deteriorating the overall performance of the battery, and improving the stability of the battery. have.

The present invention is to solve the above problems, a non-aqueous electrolyte containing a compound having a functional group capable of adsorbing metal ions eluted from a positive electrode and forming a stable SEI film at the positive electrode or the negative electrode, and a lithium secondary containing the same We would like to provide a battery.

The present invention relates to an organic solvent; lithium salt; And it provides a non-aqueous electrolyte comprising a compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ to R ₃ are each independently hydrogen; or a substituted or unsubstituted C 1 to C 6 alkyl group, A is S or P, when A is S, m is an integer of 1, R ₄ is hydrogen; an alkyl group having 3 to 6 carbon atoms unsubstituted or substituted with at least one halogen atom; a substituted or unsubstituted heteroaryl group having 3 to 7 carbon atoms; a heteroaryl group having 3 to 7 carbon atoms substituted with at least one halogen atom; a substituted or unsubstituted aryl group having 6 to 8 carbon atoms; an aryl group having 6 to 8 carbon atoms substituted with at least one halogen atom; or a cyclic carbonate group having 3 to 7 carbon atoms unsubstituted or substituted with at least one halogen atom, when A is P, m is an integer of 1 or 2, R ₄ is hydrogen; an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with at least one halogen atom; a substituted or unsubstituted heteroaryl group having 3 to 7 carbon atoms; a heteroaryl group having 3 to 7 carbon atoms substituted with at least one halogen atom; a substituted or unsubstituted aryl group having 6 to 8 carbon atoms; an aryl group having 6 to 8 carbon atoms substituted with at least one halogen atom; a cyclic carbonate group having 3 to 7 carbon atoms which is unsubstituted or substituted with at least one halogen atom; or an alkynyl group having 2 to 6 carbon atoms.

In addition, the present invention provides a lithium secondary battery comprising the non-aqueous electrolyte according to the present invention.

The compound represented by Formula 1 included in the non-aqueous electrolyte of the present invention is a compound containing a propargyl group, and adsorbs metal ion materials eluted from the positive electrode to suppress side effects inside the battery caused by the metal ion materials By forming a stable SEI film on the positive electrode or negative electrode at high temperature to suppress corrosion of the surface of the positive electrode and the negative electrode, a lithium secondary battery having excellent high temperature storage characteristics and lifespan characteristics of the battery can be realized.

The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

As used herein, the term "substituted or unsubstituted" refers to one selected from deuterium, a halogen group, a hydroxyl group, an amino group, a thiol group, a nitro group, a nitrile group, a silyl group, and a linear or branched C ₁ -C ₆ alkoxy group. It means that it is substituted with the above substituents, or does not have any substituents.

As a result of repeated research to develop a lithium secondary battery having excellent performance even at high temperatures, the present inventors used a compound containing a propargyl group as a non-aqueous electrolyte additive, thereby causing side effects inside the battery due to metal ion materials. The present invention was completed by finding out that it is possible to suppress and improve the high-temperature storage characteristics and lifespan characteristics of the battery.

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

non-aqueous electrolyte

The non-aqueous electrolyte according to the present invention includes an organic solvent, a lithium salt, and a compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ to R ₃ are each independently hydrogen; or a substituted or unsubstituted C 1 to C 6 alkyl group, A is S or P, when A is S, m is an integer of 1, R ₄ is hydrogen; an alkyl group having 3 to 6 carbon atoms unsubstituted or substituted with at least one halogen atom; a substituted or unsubstituted heteroaryl group having 3 to 7 carbon atoms; a heteroaryl group having 3 to 7 carbon atoms substituted with at least one halogen atom; a substituted or unsubstituted aryl group having 6 to 8 carbon atoms; an aryl group having 6 to 8 carbon atoms substituted with at least one halogen atom; or a cyclic carbonate group having 3 to 7 carbon atoms unsubstituted or substituted with at least one halogen atom, when A is P, m is an integer of 1 or 2, R ₄ is hydrogen; an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with at least one halogen atom; a substituted or unsubstituted heteroaryl group having 3 to 7 carbon atoms; a heteroaryl group having 3 to 7 carbon atoms substituted with at least one halogen atom; a substituted or unsubstituted aryl group having 6 to 8 carbon atoms; an aryl group having 6 to 8 carbon atoms substituted with at least one halogen atom; a cyclic carbonate group having 3 to 7 carbon atoms which is unsubstituted or substituted with at least one halogen atom; or an alkynyl group having 2 to 6 carbon atoms.

In addition, R ₁ may be hydrogen.

In addition, R ₂ and R ₃ may be hydrogen.

In addition, the halogen atom may be a fluorine atom.

In addition, the cyclic carbonate group having 3 to 7 carbon atoms is ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3 - may be pentylene carbonate or vinylene carbonate.

As a specific example, the compound represented by Formula 1 may be any one of compounds represented by Formulas 2-1 to 2-5 below.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Formula 2-4]

[Formula 2-5]

In addition, as a specific example, the compound represented by Formula 1 may be any one of compounds represented by Formulas 3-1 to 3-9 below.

[Formula 3-1]

[Formula 3-2]

[Formula 3-3]

[Formula 3-4]

[Formula 3-5]

[Formula 3-6]

[Formula 3-7]

[Formula 3-8]

[Formula 3-9]

In addition, as a specific example, the compound represented by Formula 1 may be any one of compounds represented by Formulas 4-1 to 4-9 below.

[Formula 4-1]

[Formula 4-2]

[Formula 4-3]

[Formula 4-4]

[Formula 4-5]

[Formula 4-6]

[Formula 4-7]

[Formula 4-8]

[Formula 4-9]

(1) organic solvents

As the organic solvent, various organic solvents commonly used in lithium electrolytes may be used without limitation. For example, the organic solvent may include a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, a cyclic ester-based organic solvent, or a mixed organic solvent thereof.

The cyclic carbonate-based organic solvent is a high-viscosity organic solvent that has a high dielectric constant and can well dissociate lithium salts in the electrolyte, and specific examples thereof include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene. At least one organic solvent selected from the group consisting of carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate, among them, ethylene carbonate may include. In addition, the linear carbonate-based organic solvent is an organic solvent having a low viscosity and a low dielectric constant, and representative examples thereof include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate ( EMC), at least one organic solvent selected from the group consisting of methylpropyl carbonate and ethylpropyl carbonate may be used, and specifically, ethylmethyl carbonate (EMC) may be included.

Specific examples of the linear ester-based organic solvent include at least one organic solvent selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate and butyl propionate. can

In addition, as the cyclic ester-based organic solvent, at least one organic solvent selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, ε-caprolactone, can be heard

Meanwhile, as the organic solvent, an organic solvent commonly used in an electrolyte for a lithium secondary battery may be added without limitation, if necessary. For example, at least one organic solvent of an ether-based organic solvent, an amide-based organic solvent, and a nitrile-based organic solvent may be further included.

(2) lithium salt

As the lithium salt, various lithium salts commonly used in electrolytes for lithium secondary batteries may be used without limitation. For example, the lithium salt includes Li ⁺ as a cation and F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , N(CN) ₂ ^- , BF ₄ ^- , ClO ₄ ^- as an anion. , AlO ₄ ^- , AlCl ₄ ^- , PF ₆ ^- , SbF ₆ ^- , AsF ₆ ^- , B ₁₀ Cl ₁₀ ^- , BF ₂ C ₂ O ₄ ^- , BC ₄ O ₈ ^- , PF ₄ C ₂ O ₄ ^- , PF ₂ C ₄ O ₈ ^- , (CF ₃ ) ₂ PF ₄ ^- , (CF ₃ ) ₃ PF ₃ ^- , (CF ₃ ) ₄ PF ₂ ^- , (CF ₃ ) ₅ PF ^- , (CF ₃ ) ₆ P ^- , CF ₃ SO ₃ ^- , C ₄ F ₉ SO ₃ ^- , CF ₃ CF ₂ SO ₃ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (FSO ₂ ) ₂ N ^- , CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- , (CF ₃ SO ₂ ) ₂ CH ^- , CH ₃ SO ₃ ^- , CF ₃ (CF ₂ ) ₇ SO ₃ ^- , CF ₃ CO ₂ ^- , CH ₃ CO ₂ ^- , SCN ^- and (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ may include at least one selected from the group consisting of.

Specifically, the lithium salt is LiCl, LiBr, LiI, 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 , LiTFSI (LiN(SO ₂ CF ₃ ) ₂ ), LiFSI (LiN(SO ₂ F) ₂ ), LiCH ₃ SO ₃ , LiCF ₃ CO ₂ , LiCH ₃ CO ₂ , and LiBETI (LiN(SO ₂ ) At least one selected from the group consisting of CF ₂ CF ₃ ) ₂ ) may be mentioned. Specifically, lithium salts are LiBF ₄ , LiClO ₄ , LiPF ₆ , LiBOB (LiB(C ₂ O ₄ ) ₂ ), LiCF ₃ SO ₃ , LiTFSI (LiN(SO ₂ CF ₃ ) ₂ ), LiFSI (LiN(SO ₂ F) ) ₂ ) and LiBETI (LiN(SO ₂ CF ₂ CF ₃ ) ₂ ) may include a single substance or a mixture of two or more.

The lithium salt may be appropriately changed within the range that can be used in general, but to be included in the electrolyte at a concentration of 0.8M to 4.0M, specifically, at a concentration of 1.0M to 3.0M, in order to obtain an optimal effect of forming a film for preventing corrosion of the electrode surface. can When the lithium salt is used within the above range, the mobility of lithium ions in the electrolyte is improved, so that the output and cycle characteristics of the lithium secondary battery can be improved, and the viscosity of the electrolyte is prevented from increasing, so that the impregnation of the electrolyte is improved has the effect of being

(3) additives

The non-aqueous electrolyte of the present invention may include the compound represented by Formula 1 as an additive.

In general, lithium ions discharged from a positive electrode during an initial charging process of a lithium secondary battery are decomposed by an electrolyte before being inserted into the negative electrode, thereby forming a solid electrolyte interphase (SEI) film on the surface of the negative electrode. The SEI film has a property of allowing lithium ions to pass through and blocking the movement of electrons, and serves as a protective film that prevents the electrolyte from continuing to decompose. That is, when the SEI film is formed on the surface of the anode, the decomposition of the electrolyte by electron transfer between the electrode and the electrolyte is suppressed, and the insertion and desorption of lithium ions are selectively possible.

However, in lithium secondary batteries, structural decay of the positive electrode active material or the decomposition of lithium salts in the electrolyte by repeated charging and discharging processes generate Lewis acid by-products such as PF ^-5 or HF, so that transition metals from the positive electrode active material are generated. ions are eluted. The eluted transition metal ions are redeposited on the surface of the anode to increase the resistance of the anode, and the eluted transition metal ions are electrodeposited on the surface of the cathode through the electrolyte to undergo a decomposition reaction with the components constituting the SEI film. This leads to a decrease in the passivation ability of the SEI film. In this way, the destroyed SEI film does not suppress the further decomposition reaction of the electrolyte during repeated charge and discharge, thereby lowering the mobility of lithium ions, increasing the irreversible reaction, and consequently reducing the capacity and charge and discharge efficiency of the battery. .

In the present invention, in order to solve the above problems, the compound represented by Formula 1 is used as an electrolyte additive. In the compound structure represented by Formula 1, the triple bond propargyl group and oxygen atom have metal ion adsorption performance, so metal foreign substances such as Fe, Co, Mn, Ni, etc. eluted from the positive electrode during charging and discharging of the battery, the negative electrode It can be easily adsorbed with a metal foreign material such as Cu eluted from the metal, or a metal foreign material mixed with raw materials or a manufacturing process. As a result, it is possible to prevent the eluted metal foreign material from being electrodeposited on the negative electrode and growing into a dendrite, thereby preventing the occurrence of a low voltage phenomenon in the battery due to the eluted metal foreign material. In addition, the propargyl group in the compound structure represented by Formula 1 may undergo polymerization as the triple bond is broken in the process of forming the SEI film, which may form a more robust SEI film with low resistance. As a result, it is possible to form a stable ion conductive film on the surface of the anode, thereby suppressing an additional electrolyte decomposition reaction. Therefore, when the compound represented by Formula 1 is used as an additive for an electrolyte, it is possible to improve the occurrence of low voltage in the battery by smoothly occluding and releasing lithium ions from the negative electrode even when the battery is overcharged or stored at a high temperature. , there is an effect that the high-temperature storage characteristics and long-term life characteristics of the battery are improved.

The compound represented by Formula 1 is included in an amount of 0.5 to 5 parts by weight, preferably 0.5 to 3 parts by weight, and more preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the nonaqueous electrolyte. When the compound is used within the above range, a stable SEI film is formed on the surface of the positive electrode or the negative electrode to suppress the decomposition of the electrolyte at high temperature, and there is an effect of suppressing an increase in the resistance of the battery.

(4) additional additives

On the other hand, the non-aqueous electrolyte according to the present invention prevents negative electrode collapse due to decomposition of the non-aqueous electrolyte in a high-output environment, or further improves low-temperature high-rate discharge characteristics, high-temperature stability, overcharge prevention, and battery expansion inhibition effect at high temperatures. In order to do this, if necessary, other additional additives in addition to the compound represented by Formula 1 may be further included.

Examples of such additional additives include a cyclic carbonate-based compound, a halogen-substituted carbonate-based compound, a sulfate-based compound, a phosphate-based compound, a borate-based compound, a nitrile-based compound, a benzene-based compound, an amine-based compound, a silane-based compound, and a lithium salt-based compound At least one selected from the group consisting of may be mentioned.

The cyclic carbonate-based compound may be, for example, vinylene carbonate (VC) or vinylethylene carbonate.

The halogen-substituted carbonate-based compound may be, for example, fluoroethylene carbonate (FEC).

The sulfate-based compound may be, for example, ethylene sulfate (Esa), trimethylene sulfate (TMS), or methyl trimethylene sulfate (MTMS).

The phosphate-based compound is, for example, lithium difluoro(bisoxalato)phosphate, lithium difluorophosphate, tetramethyl trimethyl silyl phosphate, trimethyl silyl phosphite, tris(2,2,2-trifluoro It may be at least one compound selected from the group consisting of ethyl) phosphate and tris (trifluoroethyl) phosphite.

The borate-based compound may be, for example, tetraphenylborate, lithium oxalyldifluoroborate, or the like.

The nitrile-based compound is, for example, succinonitrile, adiponitrile, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, From the group consisting of 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile It may be at least one or more selected compounds.

The benzene-based compound may be, for example, fluorobenzene or the like, the amine-based compound may be triethanolamine or ethylenediamine, and the silane-based compound may be tetravinylsilane.

The lithium salt-based compound is a compound different from the lithium salt included in the non-aqueous electrolyte, LiPO ₂ F ₂ , LiODFB (lithium difluorooxalatoborate (LiBF ₂ (C ₂ O ₄ )), LiBOB (lithium bisoxalatoborate) (LiB(C ₂ O ₄ ) ₂ )) and LiBF ₄ may be at least one compound selected from the group consisting of.

Among these additional additives, when vinylene carbonate, vinylethylene carbonate, or succinonitrile is included, a more robust SEI film may be formed on the surface of the positive electrode or the negative electrode during the initial activation process of the secondary battery.

When the LiBF ₄ is included, generation of a gas that may be generated due to the decomposition of the electrolyte during storage at a high temperature is suppressed, thereby improving the high-temperature stability of the secondary battery.

Meanwhile, two or more of the additional additives may be mixed and used, and may be included in an amount of 0.01 to 50% by weight, specifically 0.01 to 10% by weight, preferably 0.05 to 5% by weight, based on the total weight of the non-aqueous electrolyte. can be When the additional additives are used within the above range, there are effects of improving low-temperature output, high-temperature storage, and high-temperature lifespan characteristics of the battery.

lithium secondary battery

The lithium secondary battery according to the present invention includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is the non-aqueous electrolyte according to the present invention. Since the non-aqueous electrolyte has been described above, a description thereof will be omitted, and other components will be described below.

(1) Anode

The positive electrode according to the present invention may include a positive electrode active material layer including a positive electrode active material, and if necessary, the positive electrode active material layer may further include a conductive material and/or a binder.

The positive active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically, may be a lithium composite metal oxide including lithium and one or more transition metals such as cobalt, manganese, nickel or aluminum. . More specifically, the lithium composite metal oxide is a lithium-manganese oxide (eg, LiMnO ₂ , LiMn ₂ O ₄ , etc.), a lithium-cobalt-based oxide (eg, LiCoO ₂ , etc.), lithium-nickel-based oxide (eg, LiNiO ₂ ), lithium-nickel-manganese oxide (eg, LiNi _1-Y Mn _Y O ₂ (0<Y<1), LiMn _2-z Ni _z O ₄ (0<Z) <2), lithium-nickel-cobalt-based oxide (eg, LiNi _1-Y1 Co _Y1 O ₂ (0<Y1<1), lithium-manganese-cobalt-based oxide (eg, LiCo _1-Y2 Mn _Y2 ) O ₂ (0<Y2<1), LiMn _2-z1 Co _z1 O ₄ (0<Z1<2), lithium-nickel-manganese-cobalt oxide (eg, Li(Ni _p Co _q Mn _r1 )O ₂ (0<p<1, 0<q<1, 0<r1<1, p+q+r1=1) or Li(Ni _p1 Co _q1 Mn _r2 )O ₄ (0<p1<2, 0 < q1 <2, 0 <r2<2, p1+q1+r2=2), or lithium-nickel-cobalt-transition metal (M) oxide (eg, Li(Ni _p2 Co _q2 Mn _r3 M _S2 )O ₂ ( M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg and Mo, and p2, q2, r3 and s2 are atomic fractions of each independent element, 0 < p2 < 1, 0 < q2 <1, 0<r3<1, 0<s2<1, p2+q2+r3+s2=1) and the like, and any one or two or more of these compounds may be included.

Among them, the lithium composite metal oxide is LiCoO ₂ , LiMnO ₂ , LiNiO ₂ , lithium nickel cobalt manganese oxide (eg, Li(Ni _0.6 Mn _0.2 Co _0.2 )O ₂ ) in terms of improving the capacity characteristics and stability of the battery. , Li(Ni _0.5 Mn _0.3 Co _0.2 )O ₂ , or Li(Ni _0.8 Mn _0.1 Co _0.1 )O ₂ , etc.), or lithium nickel cobalt aluminum oxide (eg, Li(Ni _0.8 Co _0.15 Al _0.05 )O ₂ , etc.) ) and the like, and more specifically, may be a lithium nickel cobalt manganese-based oxide represented by the following Chemical Formula 5.

[Formula 5]

Li _x [Ni _y Co _z Mn _w M ¹ _v ]O _2-p A _p

In Formula 5, M ¹ is a doping element substituted at the transition metal site, W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc , Gd, Sm, Ca, Ce, Nb, Mg, B, and may be at least one element selected from the group consisting of Mo.

A is an element substituted for an oxygen site, and may be one or more elements selected from the group consisting of F, Cl, Br, I, At, and S.

Wherein x means the atomic ratio of lithium to the total transition metal in the lithium nickel cobalt manganese oxide, 1 to 1.30, preferably 1 to 1.30 or less, more preferably 1.005 to 1.30, even more preferably It may be 1.01 to 1.20.

Wherein y means the atomic ratio of nickel in the transition metal in the lithium nickel cobalt manganese oxide, 0.3 or more and less than 1, preferably 0.6 to less than 1, more preferably 0.6 to 0.95. Since a higher capacity can be realized as the content of nickel in the transition metal increases, a nickel content of 0.6 or more is more advantageous for realizing a high capacity.

The z denotes the atomic ratio of cobalt in the transition metal in the lithium nickel cobalt manganese oxide, and is greater than 0 and 0.6 or less, preferably 0.01 to 0.4.

The w denotes the ratio of manganese atoms in the transition metal in the lithium nickel cobalt manganese oxide, and is greater than 0 and 0.6 or less, preferably 0.01 to 0.4.

The v denotes the atomic ratio of the doping element M ¹ doped to the transition metal site in the lithium nickel cobalt manganese oxide, and may be 0 to 0.2, preferably 0 to 0.1. When the doping element M ¹ is added, there is an effect of improving the structural stability of the lithium nickel cobalt manganese oxide, but if the content of the doping element increases, the capacity may decrease, so it is preferably included in an amount of 0.2 or less.

The p denotes an atomic ratio of element A substituted for an oxygen site, and may be 0 to 0.2, preferably 0 to 0.1.

Meanwhile, in Formula 5, y+z+w+v=1.

Specific examples of the lithium nickel cobalt manganese oxide include LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.5 Co _0.2 Mn _0.4 O _{2 ,} LiNi _0.5 Co _0.3 Mn _0.2 O ₂ , LiNi _0.6 Co _0.2 Mn _0.2 O _{2 ,} LiNi _0.8 Co _0.1 Mn _0.1 O ₂ and the like, but are not limited thereto.

The positive active material may be included in an amount of 80 to 98% by weight, more specifically 85 to 98% by weight, based on the total weight of the positive active material layer. When the positive active material is included in the above range, excellent capacity characteristics may be exhibited.

Next, the conductive material is used to impart conductivity to the electrode, and in the configured battery, it can be used without any particular limitation as long as it has electronic conductivity without causing chemical change.

Specific examples include graphite such as natural graphite and artificial graphite; carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or a conductive polymer such as a polyphenylene derivative, and the like, and any one of them or a mixture of two or more thereof may be used.

The conductive material may be included in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the total weight of the positive electrode active material layer.

Next, the binder serves to improve the adhesion between the positive active material particles and the adhesion between the positive active material and the current collector.

Specific examples of the binder include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile (polyacrylonitrile), carboxymethyl cellulose Woods (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, and styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, and any one of them or a mixture of two or more thereof may be used. The binder may be included in an amount of 0.1 to 15% by weight, preferably 0.1 to 10% by weight, based on the total weight of the positive electrode active material layer.

The positive electrode of the present invention as described above may be manufactured according to a method for manufacturing a positive electrode known in the art. For example, in the positive electrode, a positive electrode slurry prepared by dissolving or dispersing a positive electrode active material, a binder and/or a conductive material in a solvent is applied on a positive electrode current collector, followed by drying and rolling, or separately separating the positive electrode slurry After casting on the support of the, and then peeling the support can be prepared through a method such as laminating the film obtained on the positive electrode current collector.

The positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and for example, stainless steel, aluminum, nickel, titanium, fired carbon, or carbon, nickel, titanium on the surface of aluminum or stainless steel. , silver or the like surface-treated may be used. In addition, the positive electrode current collector may typically have a thickness of 3 μm to 500 μm, and may increase the adhesion of the positive electrode material by forming fine irregularities on the surface of the current collector. For example, it may be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven body.

The solvent may be a solvent generally used in the art, dimethyl sulfoxide (DMSO), isopropyl alcohol (isopropyl alcohol), N-methylpyrrolidone (NMP), acetone (acetone) or water and the like, and any one of them or a mixture of two or more thereof may be used. The amount of the solvent used is not particularly limited, as long as it can be adjusted so that the positive electrode mixture has an appropriate viscosity in consideration of the coating thickness of the positive electrode mixture, manufacturing yield, workability, and the like.

(2) cathode

In the negative electrode according to the present invention, various negative active materials used in the art, for example, a carbon-based negative electrode active material, a silicon-based negative active material, a metal alloy, etc. may be used, and the negative electrode may include, if necessary, a conductive material and/or a binder. may include more.

Examples of the carbon-based negative active material include various carbon-based negative active materials used in the art, for example, graphite-based materials such as natural graphite, artificial graphite, and Kish graphite; pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon microbeads, liquid crystal pitches (Mesophase pitches) and petroleum and coal tar pitch derived cokes (petroleum or coal tar pitch derived cokes) High-temperature calcined carbon, soft carbon, hard carbon, etc. may be used. The shape of the carbon-based anode active material is not particularly limited, and various shapes of materials such as amorphous, plate-like, scale-like, spherical or fibrous shape may be used.

The silicon-based negative active material is, metal silicon (Si), silicon oxide (SiO _x , where 0<x≤2) silicon carbide (SiC) and a Si-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, a group 13 element, 14 It is an element selected from the group consisting of group elements, transition metals, rare earth elements, and combinations thereof, and may include at least one selected from the group consisting of (not Si). The element Y includes Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, It may be selected from the group consisting of Se, Te, Po, and combinations thereof.

Next, the conductive material is a component for further improving the conductivity of the anode active material, and may be added in an amount of 10 wt% or less, preferably 5 wt% or less, based on the total weight of the anode active material layer. Such a conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery. For example, graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used.

The binder is a component that assists in bonding between the conductive material, the active material, and the current collector, and is typically added in an amount of 0.1 wt% to 10 wt% based on the total weight of the anode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro and roethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

The negative electrode may be manufactured according to a method for manufacturing a negative electrode known in the art. For example, the negative electrode is a method of applying a negative electrode slurry prepared by dissolving or dispersing a negative electrode active material and, optionally, a binder and a conductive material in a solvent on the negative electrode current collector, rolling, drying, or applying the negative electrode slurry on a separate support. It can be prepared by casting a film on the negative electrode current collector and then laminating the film obtained by peeling the support.

The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface. Carbon, nickel, titanium, silver, etc. surface-treated, aluminum-cadmium alloy, etc. may be used. In addition, the negative electrode current collector may have a thickness of typically 3 μm to 500 μm, and similarly to the positive electrode current collector, fine irregularities may be formed on the surface of the current collector to strengthen the bonding force of the negative electrode active material. For example, it may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam body, a nonwoven body, and the like.

The solvent may be a solvent generally used in the art, dimethyl sulfoxide (DMSO), isopropyl alcohol (isopropyl alcohol), N-methylpyrrolidone (NMP), acetone (acetone) or water and the like, and any one of them or a mixture of two or more thereof may be used. The amount of the solvent used is not particularly limited, as long as it can be adjusted so that the negative electrode slurry has an appropriate viscosity in consideration of the coating thickness of the negative electrode mixture, manufacturing yield, workability, and the like.

(3) separator

The lithium secondary battery according to the present invention includes a separator between the positive electrode and the negative electrode.

The separator separates the anode and the anode and provides a passage for lithium ions to move, and can be used without any particular limitation as long as it is normally used as a separator in a lithium secondary battery. Excellent is preferred.

Specifically, as a separator, a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene/butene copolymer, ethylene/hexene copolymer, and ethylene/methacrylate copolymer. Alternatively, a laminated structure of two or more layers thereof may be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, etc. may be used. In addition, in order to secure heat resistance or mechanical strength, a coated separator containing a ceramic component or a polymer material may be used, and may optionally be used in a single-layer or multi-layer structure.

The lithium secondary battery according to the present invention as described above can be usefully used in portable devices such as mobile phones, notebook computers, digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs).

Accordingly, according to another embodiment of the present invention, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided.

The battery module or battery pack is a power tool (Power Tool); electric vehicles, including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); Alternatively, it may be used as a power source for any one or more medium and large-sized devices in a system for power storage.

The external shape of the lithium secondary battery of the present invention is not particularly limited, but may be a cylindrical shape using a can, a prismatic shape, a pouch type, or a coin type.

The lithium secondary battery according to the present invention can be used not only in a battery cell used as a power source for a small device, but can also be preferably used as a unit cell in a medium or large battery module including a plurality of battery cells.

Hereinafter, the present invention will be described in detail through specific examples. However, the following examples are for illustrative purposes only, and the scope of the present specification is not limited thereby.

Example

(Manufacture of non-aqueous electrolyte)

Ethylene carbonate (EC): After dissolving LiPF ₆ to 1.0M in 99.0 g of a non-aqueous organic solvent mixed with ethylmethyl carbonate (EMC) in a volume ratio of 3:7, a compound represented by the following formula 2-4 as an additive 1.0 g was added to prepare a non-aqueous electrolyte.

[Formula 2-4]

(anode manufacturing)

The cathode active material (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ), the conductive material (carbon black), and the binder (polyvinylidene fluoride (PVDF)) were mixed with the solvent N-methyl-2-P in a weight ratio of 97.5:1:1.5. It was added to rollidone (NMP) to prepare a cathode active material slurry (solid content: 60 wt%). The positive electrode active material slurry was applied to a positive electrode current collector (Al thin film) having a thickness of 15 μm, dried, and then roll press was performed to prepare a positive electrode.

(Cathode Manufacturing)

A negative electrode active material (graphite), a conductive material (carbon black), and a binder (polyvinylidene fluoride (PVDF)) were added to distilled water in a weight ratio of 96:0.5:3.5 to prepare a negative electrode slurry (solid content: 50% by weight). The negative electrode active material slurry was applied to a copper (Cu) thin film as an anode current collector having a thickness of 8 μm, dried, and then roll press was performed to prepare a negative electrode.

(Secondary battery manufacturing)

The positive electrode and the negative electrode prepared by the above method are laminated together with a polyethylene porous film, which is a separator, to prepare an electrode assembly, and then put it in a battery case, inject the nonaqueous electrolyte prepared by the above method, and then seal the pouch-type lithium secondary A battery (battery capacity 6.24 mAh) was manufactured.

Example 2

In the preparation of the non-aqueous electrolyte of Example 1, the lithium secondary lithium secondary in the same manner as in Example 1, except that 1.0 g of the compound represented by the following Formula 3-3 was used instead of 1.0 g of the compound represented by the Formula 2-4 as an additive. A battery was prepared.

[Formula 3-3]

Example 3

In the preparation of the non-aqueous electrolyte of Example 1, the lithium secondary lithium secondary in the same manner as in Example 1, except that 1.0 g of the compound represented by the following Formula 4-3 was used instead of 1.0 g of the compound represented by the Formula 2-4 as an additive. A battery was prepared.

[Formula 4-3]

Comparative Example 1

A lithium secondary battery was manufactured in the same manner as in Example 1, except that no additives were added during the preparation of the non-aqueous electrolyte of Example 1.

Comparative Example 2

A lithium secondary battery was prepared in the same manner as in Example 1, except that 1.0 g of the compound represented by the following formula (A) was used instead of 1.0 g of the compound represented by the formula (2-4) as an additive in the preparation of the non-aqueous electrolyte of Example 1 prepared.

[Formula A]

The contents of the organic solvents and additives of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1 below.

organic solvent additive type
(volume ratio) addition amount
(g) type addition amount
(g) Example 1 EC:EMC = 3:7 99.0 Formula 2-4 1.0 Example 2 EC:EMC = 3:7 99.0 Formula 3-3 1.0 Example 3 EC:EMC = 3:7 99.0 Formula 4-3 1.0 Comparative Example 1 EC:EMC = 3:7 100.0 - - Comparative Example 2 EC:EMC = 3:7 99.0 Formula A 1.0

Experimental Example 1: Evaluation of high temperature storage characteristics

In order to evaluate the high-temperature storage characteristics of the lithium secondary batteries prepared in Examples 1 to 3 and Comparative Examples 1 and 2, the volume change rate and resistance increase rate of the lithium secondary battery were measured as follows.

(1) Volume change rate (%)

Each of the lithium secondary batteries prepared in Examples 1 to 3 and Comparative Examples 1 and 2 was activated at 0.1C CC. Then, using a PESC05-0.5 charger/discharger (manufacturer: PNE Solution, 5V, 500mA) at 25°C under constant current-constant voltage (CC-CV) charging conditions, it was charged at 0.33C CC up to 4.2V and then 0.05C current The cut was carried out, and it was discharged at 0.33C up to 2.5V under CC conditions. The charging and discharging were performed as 1 cycle, and 2 cycles were performed. Then, it was fully charged with 0.33C/4.2V constant current-constant voltage, and discharged for 10 seconds at 2.5C at 50% SOC to calculate the initial resistance through the difference between the voltage before discharge and the voltage after discharge. Thereafter, it was discharged with a constant current of 0.33C until it became 2.5V.

Then, degassing was performed, and the initial volume was measured by putting the initially charged and discharged lithium secondary battery into a bowl filled with water at room temperature using TWD-150DM equipment from Two-pls. Next, the lithium secondary battery was fully charged at 0.33C/4.2V constant current-constant voltage, respectively, and stored at 60° C. for 4 weeks (SOC 100%), and then stored with water at room temperature using Two-pls, TWD-150DM equipment. The volume after high-temperature storage was measured by putting a lithium secondary battery in a filled bowl. The volume change rate was calculated by substituting the initial volume and the volume after high-temperature storage of the lithium secondary battery measured as described above in Equation (1), and the results are shown in Table 2 below.

- Equation (1): Volume change rate (%) = {(Volume after high temperature storage - Initial volume)/Initial volume}×100

(2) Resistance increase rate (%)

Each of the lithium secondary batteries prepared in Examples 1 to 3 and Comparative Examples 1 and 2 was activated at 0.1C CC. Then, using a PESC05-0.5 charger/discharger (manufacturer: PNE Solution, 5V, 500mA) at 25°C under constant current-constant voltage (CC-CV) charging conditions, it was charged at 0.33C CC up to 4.2V and then 0.05C current The cut was carried out, and it was discharged at 0.33C up to 2.5V under CC conditions. The charging/discharging was performed as 1 cycle, and 2 cycles were performed. Then, it was fully charged with 0.33C/4.2V constant current-constant voltage, and discharged for 10 seconds at 2.5C at 50% SOC to calculate the initial resistance through the difference between the voltage before discharge and the voltage after discharge. Thereafter, it was discharged with a constant current of 0.33C until it became 2.5V.

Then, after degassing, the lithium secondary battery is charged to 4.2V, respectively, stored at 60° C. for 4 weeks (SOC 100%), and then stored at high temperature while discharging again from SOC 50% to 2.5C for 10 seconds. The subsequent resistance was measured. The resistance increase rate was calculated by substituting the initial resistance value of the lithium secondary battery measured as described above and the resistance value after high temperature storage into Equation (2) below, and the results are shown in Table 2 below.

- Equation (2): resistance increase rate (%) = {(resistance value after high temperature storage - initial resistance value)/initial resistance value}×100

Volume change rate (%) Resistance increase rate (%) Example 1 18 16 Example 2 13 15 Example 3 15 20 Comparative Example 1 37 45 Comparative Example 2 27 42

As shown in Table 2, in Examples 1 to 3 in which the compound represented by Formula 1 according to the present invention was used as an electrolyte additive, it was confirmed that both the volume change rate and the resistance increase rate of the lithium secondary battery were low.

On the other hand, Comparative Example 1, which does not contain an additive in the electrolyte, and Comparative Example 2, which does not include the compound represented by Formula 1 even though the electrolyte contains the additive, have significantly higher volume change rate and resistance increase rate compared to Examples 1 to 3. It was confirmed that the high temperature storage characteristics of the lithium secondary battery were poor.

From these results, it can be confirmed that when the compound represented by Formula 1 according to the present invention is used as an additive for an electrolyte, a strong SEI film with high stability and low resistance can be formed, thereby providing a lithium secondary battery having excellent high-temperature storage characteristics. there was.

Experimental Example 2: Lifespan characteristic evaluation

In order to evaluate the lifespan characteristics of the lithium secondary batteries prepared in Examples 1 to 3 and Comparative Examples 1 and 2, the capacity retention rate and resistance increase rate of the lithium secondary battery were measured as follows.

Each of the lithium secondary batteries prepared in Examples 1 to 3 and Comparative Examples 1 and 2 was activated at 0.1C CC. Then, using a PESC05-0.5 charger/discharger (manufacturer: PNE Solution, 5V, 500mA) at 25°C under constant current-constant voltage (CC-CV) charging conditions, it was charged at 0.33C CC up to 4.2V and then 0.05C current The cut was carried out, and it was discharged at 0.33C up to 2.5V under CC conditions. The charging and discharging were performed as 1 cycle, and 2 cycles were performed. Then, it was fully charged with 0.33C/4.2V constant current-constant voltage, discharged at SOC 50% at 2.5C for 10 seconds, and the initial resistance was calculated through the difference between the voltage before discharging for 10 seconds and the voltage after discharging for 10 seconds. Thereafter, it was discharged with a constant current of 0.33C until it became 2.5V.

Then, after degassing, the lithium secondary battery is charged at a constant current of 0.33C under a voltage driving range of 2.5V to 4.2V, respectively, at 45° C., until it becomes 4.2V, and charged at a constant voltage of 4.2V. When the charging current reached 0.05C, charging was terminated. Then, it was allowed to stand for 20 minutes and then discharged at a constant current of 0.33C until it became 2.5V. The charge/discharge was performed as 1 cycle, and 100 cycles were performed.

At this time, the capacity after 1 cycle and the capacity after 100 cycles are measured using a PESC05-0.5 charger/discharger (manufacturer: PNE Solution, 5V, 500mA), and the capacity is substituted in the following formula (3) to after 100 cycles The capacity retention rate was calculated, and the results are shown in Table 3 below.

- Equation (3): Capacity retention rate (%) after 100 cycles = (Capacity after 100 cycles / Capacity after cycle)×100

On the other hand, 100 cycles were performed, and then the resistance after 100 cycles was calculated through the difference between the voltage before discharging for 10 seconds and the voltage after discharging for 10 seconds by discharging at SOC 50% at 2.5C for 10 seconds.

The resistance increase rate was calculated by substituting the initial resistance value measured as described above and the resistance value after 100 cycles into Equation (4) below. The results are shown in Table 3 below.

- Equation (4): resistance increase rate (%) after 100 cycles = {(resistance value after 100 cycles - initial resistance value)/initial resistance value}×100

Capacity retention rate (%) after 100 cycles Resistance increase rate (%) after 100 cycles Example 1 91 18 Example 2 89 17 Example 3 90 18 Comparative Example 1 78 40 Comparative Example 2 87 25

As shown in Table 3, in the case of Examples 1 to 3 using the compound represented by Formula 1 according to the present invention as an additive for electrolyte, the capacity retention rate after 100 cycles of the lithium secondary battery is improved, and the resistance increase rate after 100 cycles This low was confirmed.

On the other hand, in Comparative Example 1, which does not contain an additive in the electrolyte, not only the capacity retention rate significantly decreased after 100 cycles compared to Examples 1 to 3, but also the resistance increase rate after 100 cycles was greatly increased, confirming that the life characteristics of the lithium secondary battery were poor. could In addition, in Comparative Example 2, which does not include the compound represented by Formula 1, even though the electrolyte contains an additive, the capacity retention rate after 100 cycles was lowered compared to Examples 1 to 3, and the resistance increase rate after 100 cycles increased due to the increase of the lithium secondary battery. It was confirmed that the lifespan characteristics were poor.

From these results, when the compound represented by Formula 1 according to the present invention is used as an additive for an electrolyte, a strong SEI film with high stability and low resistance is formed, thereby providing a lithium secondary battery excellent in both high-temperature storage characteristics and lifespan characteristics. could confirm that there was

Claims (9)

organic solvents; lithium salt; And a non-aqueous electrolyte comprising a compound represented by the following formula (1):
[Formula 1]

In Formula 1,
R ₁ to R ₃ are each independently hydrogen; Or a substituted or unsubstituted C 1 to C 6 alkyl group,
A is S or P,
When A is S, m is an integer of 1, R ₄ is hydrogen; an alkyl group having 3 to 6 carbon atoms unsubstituted or substituted with at least one halogen atom; a substituted or unsubstituted heteroaryl group having 3 to 7 carbon atoms; a heteroaryl group having 3 to 7 carbon atoms substituted with at least one halogen atom; a substituted or unsubstituted aryl group having 6 to 8 carbon atoms; an aryl group having 6 to 8 carbon atoms substituted with at least one halogen atom; or a cyclic carbonate group having 3 to 7 carbon atoms that is unsubstituted or substituted with at least one halogen atom,
When A is P, m is an integer of 1 or 2, R ₄ is hydrogen; an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with at least one halogen atom; a substituted or unsubstituted heteroaryl group having 3 to 7 carbon atoms; a heteroaryl group having 3 to 7 carbon atoms substituted with at least one halogen atom; a substituted or unsubstituted aryl group having 6 to 8 carbon atoms; an aryl group having 6 to 8 carbon atoms substituted with at least one halogen atom; a cyclic carbonate group having 3 to 7 carbon atoms which is unsubstituted or substituted with at least one halogen atom; or an alkynyl group having 2 to 6 carbon atoms. According to claim 1,
wherein R ₁ is hydrogen. According to claim 1,
wherein R ₂ and R ₃ are hydrogen. According to claim 1,
wherein the halogen atom is a fluorine atom. According to claim 1,
The compound represented by Formula 1 is any one of the compounds represented by Formulas 2-1 to 2-5 below.
[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Formula 2-4]

[Formula 2-5]

According to claim 1,
The compound represented by Formula 1 is any one of the compounds represented by Formulas 3-1 to 3-9 below.
[Formula 3-1]

[Formula 3-2]

[Formula 3-3]

[Formula 3-4]

[Formula 3-5]

[Formula 3-6]

[Formula 3-7]

[Formula 3-8]

[Formula 3-9]

According to claim 1,
The compound represented by Formula 1 is any one of the compounds represented by Formulas 4-1 to 4-9 below.
[Formula 4-1]

[Formula 4-2]

[Formula 4-3]

[Formula 4-4]

[Formula 4-5]

[Formula 4-6]

[Formula 4-7]

[Formula 4-8]

[Formula 4-9]

According to claim 1,
The compound is included in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the nonaqueous electrolyte. A lithium secondary battery comprising the non-aqueous electrolyte according to claim 1 .