KR101586681B1 - electrolyte for lithium secondary battery and lithium secondary battery containing the same - Google Patents

Abstract

The present invention relates to a non-aqueous electrolyte for a secondary battery and a secondary battery comprising the non-aqueous electrolyte. The non-aqueous electrolyte includes a non-aqueous solvent, a lithium salt, and Tetrafluoroethane beta-sultone as an additive. The employed secondary battery has an advantage that the life temperature characteristics at high temperature and high temperature and output characteristics are improved.

Description

[0001] The present invention relates to a lithium secondary battery electrolyte and a lithium secondary battery containing the same,

The present invention relates to a non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery containing the same. More particularly, the present invention relates to a non-aqueous electrolyte, a lithium salt, and an additive, 2-oxathietane 2,2-dioxide, which can improve lifetime characteristics and output characteristics at room temperature and high temperature, and a lithium secondary battery comprising the non-aqueous electrolyte for lithium secondary battery.

A secondary battery is a chemical battery that can be used semi-permanently because it can be recharged unlike a primary battery. The market size of such a rechargeable battery has recently been increasing exponentially due to the mass supply of notebook computers, mobile communication devices, and digital cameras, and in recent years, the rechargeable battery has rapidly grown into the three major components industries of the 21st century along with the semiconductor industry and the display industry have.

The secondary battery can be divided into a lead-acid battery, a nickel-cadmium battery, a nickel-hydrogen (Ni-MH) battery and a lithium battery according to an anode material or a cathode material. Dislocations and energy densities are determined by intrinsic properties. Among these, 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 low oxidation / reduction potential and molecular weight of lithium.

Of these lithium secondary batteries, a lithium secondary battery using a nonaqueous electrolyte is coated with a lithium metal mixed oxide capable of releasing and inserting lithium ions as a cathode as a cathode as a cathode, 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 lowered due to various reasons such as repetition of charging / discharging cycles, and particularly when the battery is placed in a high temperature environment, the capacity is significantly reduced.

(1) When the transition metal contained in the composite oxide constituting the anode is eluted into the non-aqueous electrolytic solution and precipitates on the cathode, causing the structure breakdown of the positive electrode composite oxide or increasing the interface resistance.

(2) When the eluted cathode transition metal continues to grow to cause a short circuit between the anode and the 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 electrolytic solution to generate gas inside the battery.

(4) When the SEI layer of the cathode is thickened as the charge / discharge progresses, it interferes with the movement of Li ⁺ .

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

In general, the nonaqueous electrolyte secondary battery is a nonaqueous electrolyte secondary battery which is produced by a reaction between a cathode active material such as a lithium-containing metal oxide capable of occluding and releasing lithium and / or lithium ion, and an electrolyte composed of a carbonate- The electrode resistance increases and the SEI (solid electrolyte interface) layer formed on the surface of the 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 to accelerate the irreversible reaction of the battery Thereby causing a problem of significantly reducing battery 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.

The present inventors have intensively studied the electrolyte for a secondary battery. As a result, they have found that a secondary battery including Tetrafluoroethane beta-sultone as an additive to an electrolyte for a secondary battery has improved life and temperature characteristics at a room temperature and a high temperature, And filed an invention.

Japanese Patent Laid-Open No. 1996-045545 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 electrolytic solution for a lithium secondary battery which improves cycle characteristics, high-efficiency charge / discharge characteristics, excellent lifespan characteristics and output at room temperature and high temperature by using Tetrafluoroethane beta-sultone as an electrolyte additive, Battery.

(A) an additive represented by the following general formula (1); (b) a lithium salt; And (c) a nonaqueous solvent; And a non-aqueous electrolyte solution for a lithium secondary battery.

[Chemical Formula 1]

According to an embodiment of the present invention, the additive may be included in an amount of 0.05 to 10% by weight based on the total weight of the non-aqueous electrolytic solution.

According to an embodiment of the present invention, the non-aqueous solvent may be a linear carbonate-based solvent, a cyclic carbonate-based solvent, or a mixture thereof.

According to an embodiment of the present invention, the linear carbonate-based solvent is at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate Propylene carbonate (MPC), and the cyclic carbonate solvent is at least one selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate (BC), 2,3- , 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate (VC), and fluorethylene carbonate.

According to an embodiment of the present invention, the mixed solvent may be a mixture of a cyclic carbonate-based solvent and a linear carbonate-based solvent at a volume ratio of 1: 1 to 1: 9.

The lithium salt according to one embodiment of the present invention 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 . _{LiSCN, 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, LiB ( C 2 O 4) 2, LiF 2 BC 2 O ₄ , LiPF ₄ (C ₂ O ₄ ), LiPF ₂ (C ₂ O ₄ ) ₂ , LiP (C ₂ O ₄ ) ₃ and LiPO ₂ F ₂ .

According to an embodiment of the present invention, the non-aqueous electrolyte solution for a lithium secondary battery may include the lithium salt at a concentration of 0.6 to 2.0M.

The present invention provides a positive electrode 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 non-aqueous electrolytic solution for the lithium secondary battery; And d) a separator; And a lithium secondary battery.

The nonaqueous electrolyte solution for a lithium secondary battery including the additive according to the present invention is stable at high temperature as well as at room temperature and the additive effectively and stably forms a solid electrolyte interface (SEI) coating on the surface of the negative electrode to prevent side reactions between the electrolyte and the electrode, The electrochemical characteristics, lifespan characteristics, and high-temperature storage characteristics of the battery can be improved. In addition, the lithium secondary battery including the nonaqueous electrolyte according to the present invention has improved output characteristics, high efficiency charge / discharge characteristics, and excellent high temperature storage stability.

Hereinafter, the present invention will be described in more detail. Unless otherwise defined, technical terms and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the following description, And a description of the known function and configuration will be omitted.

The present invention relates to a non-aqueous electrolytic solution for a lithium secondary battery for providing a lithium secondary battery excellent in room temperature and high-temperature storage characteristics and life characteristics.

(A) an additive represented by the following general formula (1); (b) a lithium salt; And (c) a nonaqueous solvent; And a non-aqueous electrolyte solution for a lithium secondary battery.

[Chemical Formula 1]

The nonaqueous electrolytic solution for a lithium secondary battery including the additive Tetrafluoroethane beta-sultone according to the present invention can ensure high stability not only at room temperature but also at high temperature, and improve electrochemical characteristics, lifetime characteristics and high temperature storage characteristics.

In addition, when the battery is charged, the additive is subjected to reduction decomposition prior to a solvent such as EC at the surface of the negative electrode to form a stable SEI layer to prevent decomposition of the electrolyte during charge and discharge and long-term storage. It is possible to operate the additive without oxidative decomposition even in a high voltage battery of 4.5 V or more.

If the content of the additive is too high, the resistance of the battery becomes large. If the content of the additive is too low, the effect of the additive is lost. Therefore, the additive may be contained in an amount of 0.05 to 10% by weight based on the total weight of the non- Preferably from 0.1 to 5% by weight, based on the total weight of the composition.

In the non-aqueous electrolytic solution for a lithium secondary battery, the non-aqueous solvent is not limited, but a carbonate-based solvent is preferably used. The carbonate-based solvent may be a linear carbonate-based solvent, a cyclic carbonate- . Specific examples of the linear carbonate solvent include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (EMC) and methyl propyl carbonate Specific examples of the cyclic carbonate-based solvent include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate (BC), 2,3-butylene carbonate But are not limited to, pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate (VC) and fluoroethylene carbonate.

Since the cyclic carbonate-based solvent has a large polarity and can sufficiently dissociate lithium ions, it has a disadvantage in that the ionic conductivity is low due to the high viscosity. Therefore, a linear carbonate-based solvent having a low polarity but a low viscosity is mixed with the cyclic carbonate- The characteristics of the lithium secondary battery can be optimized. Therefore, it is preferable to mix at least one solvent selected from a cyclic carbonate-based solvent and at least one solvent selected from a linear carbonate-based solvent with the non-aqueous solvent. At this time, the mixed solvent may be prepared by mixing the cyclic carbonate solvent and the linear carbonate solvent at a volume ratio of 9: 1 to 1: 9, preferably 2: 8 to 8: 2, It is most preferable in terms of life characteristics and storage characteristics of the battery.

Particularly, among the cyclic carbonate solvents, ethylene carbonate (EC) or propylene carbonate (PC) having a high dielectric constant and dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) or diethyl carbonate ) Is preferably used in combination.

In the non-aqueous electrolyte solution for a lithium secondary battery according to the present invention, the lithium salt is at least one selected from the group consisting of 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 (SO 2 F) 2,} LiN (C 2 F 5 SO 3) 2, LiN (C 2 F 5 SO 2) 2, LiN (CF 3 SO 2) 2. _{LiSCN, 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, LiB ( C 2 O 4) 2, LiF 2 BC 2 O ₄ , LiPF ₄ (C ₂ O ₄ ), LiPF ₂ (C ₂ O ₄ ) ₂ , LiP (C ₂ O ₄ ) ₃ and LiPO ₂ F ₂ can be used . In this case, the lithium salt is contained in the total electrolyte solution at a concentration of 0.6 to 2.0 M, 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.

The nonaqueous electrolytic solution for a lithium 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 can improve the safety and reliability of the lithium secondary battery. Also, the non-aqueous electrolyte solution for a lithium secondary battery according to the present invention maintains electrochemically stable characteristics even at a voltage of 4.4 V, and therefore, all lithium secondary batteries such as a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery It can be applied to a battery.

The present invention provides a positive electrode 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) an electrolytic solution according to any one of claims 1 to 6; And d) a separator; And a lithium secondary battery.

The positive electrode may include a current collector and a positive electrode active material layer formed on the current collector. The cathode active material layer may include at least one material selected from a cathode active material capable of occluding and releasing lithium, a binder, and a conductive material. At this time, it is preferable that the cathode active material is a composite metal oxide of lithium and at least one kind 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 include LiCoO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiNiO ₂ or LiNi ₁ -x-yCo _x M _y O ₂ (0? _X? 1, 0? Y? 1, and M is a lithium metal oxide such as Al, Sr, Mg, Mn or La), or a lithium intercalation compound such as a lithium chalcogenide compound. However, the lithium intercalation compound is not limited to this and can be used as a positive electrode active material Any available material may be used.

The negative electrode may include a current collector and a negative electrode active material layer formed on the current collector. The negative electrode active material layer may include at least one material selected from a negative electrode active material capable of intercalating and deintercalating lithium, a binder and a conductive material. The negative electrode active material is preferably a crystalline carbon, an amorphous carbon, a carbon composite, a carbon fiber, a lithium metal, a lithium alloy, or a carbon-metal composite, but is not limited thereto and any material usable as an anode active material in a secondary battery may be used .

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 or 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. Specific examples thereof include polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene oxide, polyvinyl pyrrolidone, poly Polyvinylidene fluoride (PVdF), copolymers of polyhexafluoropropylene-polyvinylidene fluoride (PVdF / HFP)), poly (vinyl acetate), alkylated polyethylene oxide, Butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, polyacrylonitrile, Butadiene rubber, epoxy resin or nylon may be used. However, It is not.

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. Examples of the conductive material include at least one selected from the group consisting of graphite-based conductive materials, carbon black-based conductive materials, and metal and metal compound-based conductive materials. Specific examples of the graphite-based conductive material may be artificial graphite or natural graphite. Specific examples of the carbon black-based conductive material include acetylene black, ketjen black, denka black, thermal black, or channel And black (channel black), and specific examples of the metal or metal compound conductive material include perovskite such as tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ , LaSrMnO ₃ , ), But it is not limited to the above-mentioned conductive materials.

Further, if necessary, a thickener may be further used, and it is not particularly limited as long as it can control the slurry viscosity of the active material. Specific examples thereof include carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose or hydroxypropylcellulose Lt; / RTI >

As the solvent in which the electrode active material, the binder and the conductive material are dispersed, a non-aqueous solvent, an aqueous solvent or a mixed solvent thereof may be used. The non-aqueous solvent may be N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, N, N-dimethylaminopropylamine, ethylene oxide or tetrahydrofuran.

The lithium secondary battery according to the present invention may include a separator to prevent a short circuit between the positive electrode and the negative electrode and to provide a passage for lithium ion. Examples of the separator include a polypropylene, a polyethylene, a polyethylene / polypropylene, A polyolefin-based polymer monolayer such as propylene / polyethylene or polypropylene / polyethylene / polypropylene, or a multilayer thereof, a microporous film, a woven fabric or a nonwoven fabric may be used.

Further, the lithium secondary battery is preferably formed in a square, cylindrical or pouch shape, but the shape of the battery is not limited thereto.

The present invention will be described in detail with reference to the following examples. However, the following examples are merely examples of the present invention, and the claims of the present invention are not limited thereto.

[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 prepared by dissolving LiPF ₆ to a concentration of 1.0 M in a mixed solvent of ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3: 7 by volume) and then adding 0.5 wt% of Tetrafluoroethane beta-sultone.

Using the lithium secondary battery manufactured by the above-described manufacturing method, the cycle of charging 1 C to 4.2 V and discharging 2 C was repeated 300 times to measure the lifetime characteristics (cycle performance). The cycle life characteristics at room temperature (25 캜) were evaluated by calculating the initial discharge capacity and the discharge capacity at 300 cycles as a percentage relative to the initial capacity (see Table 1), and the lithium secondary battery manufactured by the above- And the process of discharging at 2C after charging 1C to 4.2V was repeated 300 times to measure high temperature lifetime characteristics. The cycle life characteristics at a high temperature (45 캜) were evaluated by calculating the initial discharge capacity and the discharge capacity at 300 cycles as a percentage of the initial capacity (see Table 2).

Also, the lithium secondary battery manufactured by the above-described method was charged at 1 C to 4.2 V, and then the AC impedance was measured using an impedance analyzer to evaluate the battery resistance characteristics of the lithium secondary battery (see Table 3).

[Example 2]

A lithium secondary battery was prepared in the same manner as in Example 1 except that 1 wt% was added instead of 0.5 wt% of tetrafluoroethane beta-sultone, and the cycle life at room temperature (25 ° C) and at high temperature (45 ° C) And the resistance characteristics of the battery were evaluated (see Tables 1 to 3).

[Example 3]

0.5% by weight of vinylene carbonate (VC) was further added to the composition of Example 2 to prepare a lithium secondary battery, and the cycle life characteristics at room temperature (25 占 폚) and the high temperature (45 占 폚) (See Tables 1 to 3).

[Comparative Example 1]

A lithium secondary battery was prepared in the same manner as in Example 1 except that tetrafluoroethane beta -sultone was not added, and the cycle life characteristics at room temperature (25 DEG C) and the high temperature (45 DEG C) and the resistance characteristics of the battery were evaluated (See Tables 1 to 3).

[Comparative Example 2]

A secondary battery was prepared by adding 0.5 wt% of VC instead of Tetrafluoroethane beta-sultone in Example 1 and the cycle life characteristics and the resistance characteristics of the battery at room temperature (25 ° C) and high temperature (45 ° C) See Table 3).

As shown in Table 1, it was confirmed that even when the electrolytic solution of Examples 1 to 3 of the present invention had 300 cycles, the cycle capacity ratio to the initial capacity was superior to that of Comparative Examples 1 and 2, It was confirmed that when the additive of the present invention and VC were used together, it showed better room temperature lifetime performance.

As shown in Table 2, it was confirmed that the electrolytic solutions of Examples 1 to 3 of the present invention show excellent high-temperature lifetime performance as compared with Comparative Examples 1 and 2. From the results of Example 3, And it was confirmed that the use of the present invention shows better high-temperature lifetime performance.

As shown in Table 3, the electrolytic solution of Examples 1 to 3 of the present invention has a lower resistance value than that of Comparative Examples 1 and 2, making it possible to produce a high output lithium secondary battery.

As described above, the present invention provides a lithium secondary battery using a non-aqueous electrolyte for a lithium secondary battery including Tetrafluoroethane beta-sultone as an additive, has excellent storage stability at room temperature and high temperature, has a stable lifetime characteristic, And high power.

Claims (8)

In the electrolyte solution for a secondary battery,
(a) Tetrafluoroethane beta-sultone, which is an additive represented by the following formula (1); (b) a lithium salt; And (c) a non-aqueous solvent which is a linear carbonate-based solvent, a cyclic carbonate-based solvent or a mixed solvent thereof; And a non-aqueous electrolyte solution for a lithium secondary battery.
[Chemical Formula 1]

The method according to claim 1,
Wherein the additive is contained in an amount of 0.05 to 10% by weight based on the total weight of the electrolyte solution. delete The method according to claim 1,
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. The method according to claim 1,
Wherein the mixed solvent is a mixture of a cyclic carbonate solvent and a linear carbonate solvent in a volume ratio of 1: 1 to 1: 9. The method according to claim 1,
Wherein the lithium salt is selected from the group consisting of 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 (SO ₂ F) ₂ , _{LiN (C 2 F 5 SO 3} ) 2, LiN (C 2 F 5 SO 2) 2, LiN (CF 3 SO 2) 2. _{LiSCN, 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, LiB ( C 2 O 4) 2, LiF 2 BC 2 Which is one or a mixture of two or more selected from the group consisting of LiPO ₄ , LiPF ₄ (C ₂ O ₄ ), LiPF ₂ (C ₂ O ₄ ) ₂ , LiP (C ₂ O ₄ ) ₃ and LiPO ₂ F ₂ Non-aqueous electrolytic solution. The method according to claim 1,
Wherein the lithium salt is present in a concentration of 0.6 to 2.0 M. 6. A non-aqueous electrolyte solution for a lithium secondary battery, A positive electrode comprising a positive electrode active material capable of intercalating and deintercalating lithium;
An anode including a negative electrode active material capable of intercalating and deintercalating lithium;
An electrolytic solution according to any one of claims 1, 2, and 4 to 7; And
Separation membrane; ≪ / RTI >