KR20150024478A - Non-aqueous electrolyte for Secondary Batteries and Secondary Batteries containing the same - Google Patents

Abstract

The present invention relates to a nonaqueous electrolyte for secondary batteries and the secondary batteries comprising the same. The nonaqueous electrolyte comprises a nonaqueous solvent, lithium salt, a sulfonate compound, and at least one selected between an amide compound and an oxazolidinone compound as a supplemental additive. The secondary batteries comprising the nonaqueous electrolyte according to the present invention have advantages of improving electrochemical properties and life characteristics at high temperatures.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte for a secondary battery and a secondary battery including the same,

The present invention relates to a non-aqueous electrolyte for a secondary battery and a secondary battery comprising the same. More particularly, the present invention relates to a non-aqueous solvent, a lithium salt, a sulfonate compound, and an auxiliary additive which contain at least one selected from amide compounds and oxazolidinone compounds To a non-aqueous electrolytic solution for a secondary battery and a secondary battery including the same, which can improve electrochemical characteristics and lifetime characteristics at a high temperature without affecting battery characteristics.

A secondary battery is a chemical battery which can be recharged unlike a primary battery and can be used semi-permanently. Such secondary batteries have been expanding exponentially in recent years due to the massive supply of notebook computers, mobile communication devices, digital cameras, etc. Especially, in recent years, with the semiconductor industry and the display industry, .

The secondary battery is classified into a lead-acid battery, a nickel-cadmium battery, a nickel-hydrogen (Ni-MH) battery and a lithium battery according to an anode material and a cathode material. The potential and the energy density are determined. Among them, lithium secondary batteries are widely used as driving power sources for portable electronic devices such as notebook computers, camcorders, and mobile phones because of their high energy density due to the low oxidation / reduction potential and molecular weight of lithium.

Of these lithium secondary batteries, a lithium secondary battery using a nonaqueous electrolyte has a cathode coated with a lithium metal mixed oxide capable of releasing and inserting lithium ions as a cathode active material, and a negative electrode an anode is coated with a carbon material or metal lithium as a negative electrode active material, and an electrolyte in which a lithium salt is appropriately dissolved in an organic solvent is disposed between the positive electrode and the negative electrode.

However, such a secondary battery has a problem that the capacity of the battery is deteriorated due to various reasons such as repetition of the charge / discharge cycle, and particularly when the battery is placed in a high temperature environment, the capacity is significantly reduced.

(1) the transition metal contained in the composite oxide constituting the positive electrode is eluted into the non-aqueous electrolyte and precipitates on the negative electrode, causing the structure breakdown of the positive electrode composite oxide or increasing the interface resistance;

(2) the eluted cathode transition metal continues to grow to cause microcurrent shorting between the anode / cathode;

(3) the case where the positive electrode transition metal deposited on the negative electrode acts as a catalyst promoting the decomposition of the nonaqueous electrolyte to generate gas inside the battery;

(4) When the SEI layer of the cathode is thickened as the charge / discharge progresses, and the Li ⁺ migration is disturbed

(5) When the SEI layer collapses gradually due to the expansion / contraction of the negative electrode active material.

In general, a nonaqueous electrolyte secondary battery is a battery in which (1) a positive electrode active material such as a lithium-containing metal oxide capable of intercalating and deintercalating lithium and / or lithium ions, and an electrolyte composed of a carbonate- (2) a solid electrolyte interface (SEI) layer formed on the surface of a negative electrode active material capable of intercalating and deintercalating lithium and / or lithium ions is slowly destroyed at a high temperature due to continuous charging / discharging, By accelerating the irreversible reaction, there is a problem of remarkably reducing the cell performance and efficiency.

In order to solve the above-mentioned problems, Japanese Patent Laid-Open No. 1996-45545 discloses a method of using vinylene carbonate (VC) as an electrolyte additive capable of forming an SEI film on a surface of a negative electrode. However, VC is easily decomposed at the anode at high temperature cycle or high temperature storage to generate gas, which deteriorates performance and safety of the battery. In addition, in JP-A-2002-329528, an unsaturated sultone compound was used to suppress the generation of gas at a high temperature. Japanese Patent Application Laid-Open No. 2001-006729 discloses use of a carbonate-based compound containing a vinyl group to improve high temperature storage characteristics. However, SEI films are still not robust enough to solve the conventional problems.

Therefore, there is a need for research on performance improvement and stability of secondary batteries at high temperatures.

Japanese Patent Laid-Open No. 1996-45545 Japanese Patent Laid-Open No. 2002-329528 Japanese Patent Laid-Open No. 2001-006729

An object of the present invention is to provide a non-aqueous electrolyte solution for a secondary battery which is stable not only at room temperature but also at a high temperature, and can improve electrochemical characteristics, lifetime characteristics, and high-temperature storage characteristics.

Another object of the present invention is to provide a secondary battery comprising the non-aqueous electrolytic solution.

In order to achieve the above object,

Non-aqueous solvent;

Lithium salts;

A sulfonate compound of the following formula (1); And

And at least one auxiliary additive selected from oxazolidinone compounds of the following general formula (2) and amide compounds of the general formula (3).

[Chemical Formula 1]

(In the above formula (1), L is an alkylene group of C1 to C10.)

(2)

(In the above formula (2), R is a C1 to C10 alkyl group.)

(3)

(Wherein R ₁ and R ₂ are each independently a C 1 to C 10 alkyl group).

In the non-aqueous electrolytic solution for a secondary battery according to an embodiment of the present invention, the sulfonate compound and the auxiliary additive may each be contained in an amount of 0.05 to 20% by weight based on the total weight of the electrolytic solution.

In the non-aqueous electrolyte for a secondary battery according to an embodiment of the present invention, the sulfonate compound may be selected from methylene methanedisulfonate or ethylene methanedisulfonate, and the oxazolidinone compound May be selected from 3-methyl-2-oxazolidinone or 3-ethyl-2-oxazolidinone, and the amide compound may be selected from dimethylacetate Amide (dimethylacetamide) or ethylmethyl acetamide.

In the non-aqueous electrolyte for a secondary battery according to an embodiment of the present invention, the non-aqueous solvent may be selected from a linear carbonate solvent, a cyclic carbonate solvent or a mixed solvent thereof. The linear carbonate solvent may be selected from the group consisting of dimethyl carbonate ), Diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (EMC) and methyl propyl carbonate (MPC), and the cyclic carbonate- Ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate (BC), 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, (VC) and fluoroethylene carbonate.

In the nonaqueous electrolyte solution for a secondary battery according to an embodiment of the present invention, the cyclic carbonate solvent and the chain carbonate solvent may be mixed at a ratio of 1: 1 to 1: 9 by volume.

In the non-aqueous electrolytic solution for a lithium secondary battery according to an embodiment of the present invention, the lithium salt is LiPF ₆ , LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiSbF ₆ , LiAlO ₄ , LiAlCl ₄ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN (C ₂ F ₅ SO ₃ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ . _{LiN (C x F 2x +1 SO} 2) (C y F 2y +1 SO 2) ( in this example, x, y are natural numbers), LiCl, LiI, and LiB (C ₂ O ₄₎ one selected from the group consisting of ₂ Or more, and the concentration thereof may be 0.6 to 2.0 M in the total electrolyte solution.

The present invention also provides a lithium secondary battery comprising: a) a positive electrode comprising a positive electrode active material capable of intercalating and deintercalating lithium; b) a negative electrode comprising a negative electrode active material capable of intercalating and deintercalating lithium; c) a nonaqueous electrolytic solution for the secondary battery; And d) a separator.

The non-aqueous electrolytic solution for a secondary battery according to the present invention is stable at a high temperature as well as at a normal temperature without affecting battery characteristics due to the combination of at least one auxiliary additive selected from an amide compound and an oxazolidinone compound and a sulfonate compound, Characteristics, lifespan characteristics, and high-temperature storage characteristics can be improved. In addition, the secondary battery including the non-aqueous electrolyte of the present invention has an advantage of improving the high-temperature lifetime characteristics, reducing the internal resistance of the battery, and excellent in high-temperature storage characteristics.

1 is a graph showing a change in capacitance according to the number of charging and discharging cycles of the secondary batteries manufactured in Examples 1 to 3 and Comparative Examples 1 and 2

Hereinafter, the present invention will be described in detail. However, unless otherwise defined in technical terms and scientific terms used herein, it is to be understood that the technical scope of the present invention is not limited thereto. A description of known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted in the following description.

The present invention relates to a nonaqueous solvent; Lithium salts; A sulfonate compound of the following formula (1); And at least one auxiliary additive selected from an oxazolidinone compound represented by the following formula (2) and an amide compound represented by the following formula (3), and a secondary battery comprising the electrolyte.

[Chemical Formula 1]

(In the above formula (1), L is an alkylene group of C1 to C10.)

(2)

(In the above formula (2), R is a C1 to C10 alkyl group.)

(3)

(In the above formula (3), R ₁ and R ₂ are each independently C1 to C10 alkyl.)

The non-aqueous electrolytic solution for a secondary battery according to the present invention comprises the sulfonate compound of Formula 1; And at least one auxiliary additive selected from the oxazolidinone compound of the formula (2) and the amide compound of the formula (3) together, it is more effective in suppressing discoloration than using the sulfonate alone and secures high stability not only at room temperature but also at high temperature And improve electrochemical characteristics, lifetime characteristics, and high-temperature storage characteristics.

In the non-aqueous electrolyte solution for a secondary battery according to an embodiment of the present invention, the sulfonate compound forms a stable protective layer on the electrode, and the auxiliary additive contributes to inhibit hydrofluoric acid formation and stabilize the sulfonate compound. When the sulfonate compound and the auxiliary additive are used together, it improves the discoloration inhibiting property and the high temperature battery life efficiency in addition to each role. The sulfonate compound and the auxiliary additive may be contained in an amount of 0.05 to 20% by weight based on the total weight of the electrolytic solution, but preferably the sulfonate compound is contained in an amount of 0.1 to 10% by weight based on the total weight of the electrolytic solution, And 0.1 to 10% by weight based on the weight. When the sulfonate compound is contained in an amount of less than 0.05% by weight, the battery characteristics and the sulfonate compound characteristics are not exhibited. If the sulfonate compound is contained in an amount exceeding 20% by weight, battery characteristics and sulfonate compound characteristics are deteriorated. If the auxiliary additive is contained in an amount of less than 0.05% by weight, there is a problem that the auxiliary performance is not exhibited as an auxiliary additive. When the auxiliary additive is contained in an amount exceeding 20% by weight, the characteristics are deteriorated.

The sulfonate compound is preferably selected from methylene methanedisulfonate or ethylene methanedisulfonate and the oxazolidinone compound is preferably 3-methyl-2-oxazolidinone (3- methyl-2-oxazolidinone or 3-ethyl-2-oxazolidinone, and the amide compound is preferably selected from the group consisting of dimethylacetamide or ethyl methyl acetamide ).

In the non-aqueous electrolyte for a secondary battery according to an embodiment of the present invention, the non-aqueous solvent is not limited, but a carbonate-based solvent is preferably used. The carbonate-based solvent is selected from a linear carbonate-based solvent, a cyclic carbonate-based solvent, or a mixed solvent thereof. The linear carbonate solvent may be selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (EMC) and methyl propyl carbonate And the cyclic carbonate solvent may be selected from ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate (BC), 2,3-butylene carbonate, 1,2-pentylene carbonate, , 3-pentylene carbonate, vinylene carbonate (VC), and fluorethylene carbonate.

Since the cyclic carbonate solvent has a large polarity and can sufficiently dissociate lithium ions, there is a disadvantage in that the ion conductivity is low due to the high viscosity. Therefore, by using a linear carbonate solvent having a low polarity but a low viscosity in the cyclic carbonate solvent, The characteristics of the secondary battery can be optimized. Therefore, it is preferable to mix at least one solvent selected from a cyclic carbonate solvent and at least one solvent selected from a linear carbonate solvent as the non-aqueous solvent. In this case, the cyclic carbonate solvent and the chain carbonate solvent are mixed in a ratio of 9: 1 to 1: 9 based on the volume ratio, preferably 2: 8 to 8: 2, And is most preferable in terms of life characteristics and storage characteristics of the battery.

Particularly, it is preferable to use ethylene carbonate and propylene carbonate having a high dielectric constant in the cyclic carbonate-based solvent and ethylene carbonate in the case where artificial graphite is used as the negative electrode active material. In the chain carbonate-based solvent, Carbonate, ethyl methyl carbonate and diethyl carbonate are preferably used.

In the non-aqueous electrolytic solution for a secondary battery according to an embodiment of the present invention, the lithium salt acts as a source of lithium ions in the battery to enable operation of a basic lithium battery. As the lithium salt, _{LiPF 6, LiClO 4, LiAsF 6} , LiBF 4, LiSbF 6, LiAlO 4, LiAlCl 4, LiCF 3 SO 3, LiC 4 F 9 SO 3, LiN (C 2 F 5 SO 3) 2, LiN ( C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ . _{LiN (C x F 2x +1 SO} 2) (C y F 2y +1 SO 2) ( in this example, x, y are natural numbers), LiCl, LiI, and LiB (C ₂ O ₄₎ one selected from the group consisting of ₂ Or more. The lithium salt is contained in the total electrolyte solution at a concentration of 0.6 to 2.0 M, and preferably in the range of 0.7 to 1.6 M in consideration of the properties related to the electric conductivity and the viscosity related to the lithium ion mobility. If the concentration of the lithium salt is less than 0.6M, the electric conductivity of the electrolytic solution is lowered, and the performance of the non-aqueous electrolytic solution which transfers ions at a high speed between the anode and the cathode of the lithium secondary battery deteriorates. When the concentration exceeds 2.0M, The viscosity increases and the mobility of lithium ions is rather reduced.

The nonaqueous electrolytic solution for a secondary battery of the present invention has excellent storage characteristics in a temperature range of -10 to 60 캜, can maintain a long life, and improves the safety and reliability of the lithium secondary battery.

The present invention also provides a lithium secondary battery comprising: a) a positive electrode comprising a positive electrode active material capable of intercalating and deintercalating lithium; b) a negative electrode comprising a negative electrode active material capable of intercalating and deintercalating lithium; c) a nonaqueous electrolytic solution for the secondary battery; And d) a separator.

Non-limiting examples of the secondary battery include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, and a lithium ion polymer secondary battery.

The positive electrode active material is preferably a composite metal oxide of lithium and at least one element selected from cobalt, manganese, and nickel. In addition to these metals, the employment rate of the metals may be varied. In addition to these metals, Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Sr, V, and a rare earth element. Specific examples of the positive electrode active material may include a compound represented by any one of the following formulas:

The positive electrode includes a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material capable of absorbing and desorbing lithium, a binder, a conductive material, and the like. As the cathode active material, LiCoO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiNiO ₂ or LiNi _1-xy Co _x M _y O ₂ (0? _X? 1, 0? _Y? 1, 0? _X + A lithium metal oxide such as Al, Sr, Mg, Mn or La), or a lithium intercalation compound such as a lithium chalcogenide compound may be used. However, the lithium intercalation compound may be any arbitrary Materials can be used.

The negative electrode includes a current collector and a negative electrode active material layer formed on the current collector. The negative electrode active material layer may include a negative electrode active material capable of intercalating and deintercalating lithium, a binder, a conductive material, and the like. As the negative electrode active material, crystalline carbon, amorphous carbon, carbon composite, carbon fiber, lithium metal, lithium alloy, carbon-metal composite, or the like can be used, and any material that can be used as the negative electrode active material in the secondary battery can be used have.

The anode and / or the cathode may be prepared by dispersing an electrode active material, a binder and a conductive material, if necessary, a thickener in a solvent to prepare an electrode slurry composition, and applying the slurry composition to an electrode current collector. As the positive electrode current collector, aluminum or an aluminum alloy may be commonly used, and copper or a copper alloy may be used as the negative electrode current collector. The anode current collector and the anode current collector may be in the form of a foil or a mesh.

The binder may be any material that can be used by those skilled in the art, for example, by pasting the active material, mutual adhesion of the active material, adhesion to the current collector, buffering effect on expansion and contraction of the active material, and the like. For example, there may be mentioned polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene oxide, polyvinylpyrrolidone, polyurethane, Polyvinylidene fluoride (PVdF), copolymer of polyhexafluoropropylene-polyvinylidene fluoride (PVdF / HFP)), poly (vinyl acetate), alkylated polyethylene oxide, polyvinyl Butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, polyacrylonitrile, , Epoxy resin, nylon, and the like can be used, but the present invention is not limited thereto.

The conductive material is used for imparting conductivity to the electrode. Any conductive material may be used for the battery without causing any chemical change. As the conductive material, at least one selected from the group consisting of a graphite-based conductive material, a carbon black-based conductive material, and a metal or metal compound-based conductive material may be used. Examples of the black graphite conductive material include artificial graphite and natural graphite. Examples of the carbon black conductive material include acetylene black, ketjen black, denkablack, thermal black, channel black black or the like. Examples of metal or metal compound conductive agents include perovskite materials such as tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ and LaSrMnO ₃ have. However, the present invention is not limited to the above-mentioned conductive materials.

The thickening agent is not particularly limited as long as it can serve to control the viscosity of the active material slurry. For example, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and the like can be used.

As the solvent in which the electrode active material, the binder, the conductive material and the like are dispersed, a non-aqueous solvent or an aqueous solvent is used. Examples of the non-aqueous solvent include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, N, N-dimethylaminopropylamine, ethylene oxide and tetrahydrofuran.

The secondary battery of the present invention may include a separator for preventing a short circuit between the positive electrode and the negative electrode and for providing a path for the lithium ion. Examples of the separator include a polypropylene, a polyethylene, a polyethylene / polypropylene, a polyethylene / polypropylene / , Polyolefin-based polymer membranes such as polypropylene / polyethylene / polypropylene, or multi-membranes thereof, microporous films, woven fabrics and nonwoven fabrics. Further, a film coated with a resin having excellent stability may be used for the porous polyolefin film.

The secondary battery of the present invention may have other shapes such as a cylindrical shape, a pouch shape, and the like.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided only for the purpose of easier understanding of the present invention, and the following examples are merely illustrative and not intended to limit the scope of the present invention in any way.

[Example 1]

LiCoO ₂ as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binder and carbon black as a conductive material were mixed at a weight ratio of 92: 4: 4 and then dispersed in N-methyl-2-pyrrolidone to prepare a positive electrode slurry . This slurry was coated on an aluminum foil having a thickness of 20 mu m, followed by drying and rolling to prepare a positive electrode.

Acetylene black as a conductive material and polyvinylidene fluoride (PVdF) as a binder were mixed in a weight ratio of 92: 1: 7 and dispersed in N-methyl-2-pyrrolidone as an anode active material to obtain an anode active material slurry . This slurry was coated on a copper foil having a thickness of 15 mu m, followed by drying and rolling to prepare a negative electrode.

A thickness of 20 mu m Polyethylene (PE) film A separator was stacked and wound and compressed to form a cell using a pouch having a size of 6 mm x 35 mm x 60 mm and a non-aqueous electrolyte solution was injected to prepare a lithium secondary battery .

The electrolyte solution was dissolved in a mixed solvent of ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3: 7 by volume) so that LiPF ₆ became 1.0 M and then 1% by weight of methylene methane disulfonate (MMDS) And 1% by weight of 3-methyl-2-oxazolidinone.

[Example 2]

A secondary battery was prepared in the same manner as in Example 1, except that 1 wt% of dimethyl acetamide was used instead of 3-methyl-2-oxazolidinone as an auxiliary additive.

[Example 3]

A secondary battery was prepared in the same manner as in Example 1, except that 1 wt% of dimethyl acetamide was further added as an auxiliary additive.

[Comparative Example 1]

A secondary battery was prepared in the same manner as in Example 1 except that 3-methyl-2-oxazolidinone was not added.

[Comparative Example 2]

A secondary battery was prepared in the same manner as in Comparative Example 1, except that methylene methane disulfonate was not added.

[Property evaluation 1: Evaluation of cycle life characteristics at high temperature (45 캜)] [

The initial discharge capacities of each of the secondary batteries manufactured in Examples 1 to 3 and Comparative Examples 1 to 2 after charging 1 C to 4.2 V and the discharge capacity at 500 cycles and the percentages relative to the initial capacity are shown in Table 1 1 as a graph.

The initial discharge capacity (mAh) Discharge capacity after 500 cycles (mAh) life span(%) Improvement rate (% compared to Comparative Example 2) Example 1 911 620 68 9 Example 2 915 636 70 11 Example 3 910 672 74 15 Comparative Example 1 905 559 62 3 Comparative Example 2 901 531 59 -

As shown in Table 1 and Fig. 1, even when the electrolytic solution of Examples 1 to 3 of the present invention had 500 cycles, the cycle capacity ratio to the initial capacity was improved as compared with Comparative Examples 1 and 2, and stable life characteristics were shown.

Thus, as shown in Evaluation 1, the nonaqueous electrolyte solution for a secondary battery according to the present invention comprises a sulfonate compound; And at least one auxiliary additive selected from an oxazolidinone compound and an amide compound are included together to improve cycle life characteristics at a high temperature.

[Property evaluation 2: Evaluation of storage property at high temperature (80 DEG C) for 7 days)

Each of the secondary batteries prepared in Examples 1 to 3 and Comparative Examples 1 and 2 was charged at a rate of 0.5 C to 4.2 V, discharged at a rate of 2.75 V at 0.2 C, charged again to 4.2 V at 0.5 C, and the thickness and IR were measured. After the storage, the battery was discharged at 2.75V 0.2C after the storage, and the battery was charged twice to 4.2V at 0.5C to measure the first discharge capacity, the initial discharge capacity, the second discharge capacity, and the discharge capacity percentage relative to the initial discharge capacity as the capacity maintenance rate and capacity The recovery rates are shown in Table 2 below.

Capacity retention rate
(%) Capacity recovery rate
(%) Maintenance capacity improvement ratio (% compared to Comparative Example 2) Recovery capacity improvement rate (% compared to Comparative Example 2) Example 1 78.7 83.9 11.3 12.0 Example 2 79.5 85.4 12.1 13.5 Example 3 83.6 88.2 16.2 16.3 Comparative Example 1 75.8 80.6 8.4 8.7 Comparative Example 2 67.4 71.9 - -

As shown in Table 2, the electrolytes of Examples 1 to 3 and Comparative Example 1 of the present invention exhibited improved capacity retention and recovery rates than those of Comparative Example 2, and the electrolytes of Examples 1 to 3 Which is superior to Comparative Example 1.

Thus, as shown in Evaluation 2, the non-aqueous electrolytic solution for a secondary battery according to the present invention comprises a sulfonate compound; And at least one auxiliary additive selected from an oxazolidinone compound and an amide compound are included together to improve the high-temperature storage characteristics.

Claims (10)

Non-aqueous solvent;
Lithium salts;
A sulfonate compound of the following formula (1); And
At least one auxiliary additive selected from an amide compound of the formula (2) and an oxazolidinone compound of the formula (3);
And a non-aqueous electrolyte solution for a lithium secondary battery.
[Chemical Formula 1]

(In the above formula (1), L is an alkylene group of C1 to C10.)
(2)

(In the above formula (2), R is a C1 to C10 alkyl group.)
(3)

(In the above formula (3), R ₁ and R ₂ are each independently C1 to C10 alkyl.) The method according to claim 1,
Wherein the sulfonate compound and the auxiliary additive are contained in an amount of 0.05 to 20% by weight based on the total weight of the electrolytic solution. The method according to claim 1,
Wherein the sulfonate compound is methylene methanedisulfonate or ethylene methanedisulfonate. 2. A non-aqueous electrolyte solution for a lithium secondary battery according to claim 1, wherein the sulfonate compound is methylene methanedisulfonate or ethylene methanedisulfonate. The method according to claim 1,
The oxazolidinone compound is a non-aqueous electrolyte solution for a lithium secondary battery which is 3-methyl-2-oxazolidinone or 3-ethyl-2-oxazolidinone . The method according to claim 1,
Wherein the amide compound is dimethylacetamide or ethylmethyl acetamide. 2. The non-aqueous electrolyte according to claim 1, wherein the amide compound is dimethyl acetamide or ethyl methyl acetamide. The method according to claim 1,
The non-aqueous solvent is a linear carbonate-based solvent, a cyclic carbonate-based solvent, or a mixed solvent thereof. The method according to claim 6,
The linear carbonate solvent may be selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (EMC) and methyl propyl carbonate And the cyclic carbonate solvent is one or more selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate (BC), 2,3-butylene carbonate, And at least one selected from the group consisting of ethylene carbonate, 2,3-pentylene carbonate, vinylene carbonate (VC), and fluoroethylene carbonate. 8. The method of claim 7,
Wherein the cyclic carbonate solvent and the chain carbonate solvent are mixed in a volume ratio of 1: 1 to 1: 9. The method according to claim 1,
The lithium salt is _{LiPF 6, LiClO 4, LiAsF 6} , LiBF 4, LiSbF 6, LiAlO 4, LiAlCl 4, LiCF 3 SO 3, LiC 4 F 9 SO 3, LiN (C 2 F 5 SO 3) 2, LiN ( C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ . _{LiN (C x F 2x + 1} SO 2) (C y F 2y + 1 SO 2) ( in this example, x, y are natural numbers), LiCl, LiI, and LiB (C ₂ O ₄₎ one selected from the group consisting of ₂ Or more, and the concentration thereof is 0.6 to 2.0 M in the whole electrolytic solution. a) a positive electrode comprising a positive electrode active material capable of intercalating and deintercalating lithium;
b) a negative electrode comprising a negative electrode active material capable of intercalating and deintercalating lithium;
c) an electrolytic solution according to any one of claims 1 to 9; And
d) a separator;
≪ / RTI >

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