KR101340016B1 - Nonaqueous electrolytes for lithium rechargeable battery and lithium rechargeable battery using the same - Google Patents

Abstract

The present invention relates to a non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery using the electrolyte, and more particularly, to a non-aqueous electrolyte solution for a lithium secondary battery containing trifluoromethyl fluorobenzene and a lithium secondary battery using the electrolyte. .

According to the present invention, when trifluoromethyl fluorbenzene is added as an electrolyte solution additive, the capacity is maintained by repeating charge and discharge cycles, thereby improving the life characteristics.

In addition, when the secondary battery is left at a high temperature, the battery thickness increase rate due to swelling is reduced, and there is an effect of preventing a decrease in voltage when the high temperature is left.

Trifluoromethyl fluorbenzene, non-aqueous electrolyte, lithium secondary battery

Description

Non-aqueous electrolyte for lithium secondary battery and lithium secondary battery using said electrolyte {NONAQUEOUS ELECTROLYTES FOR LITHIUM RECHARGEABLE BATTERY AND LITHIUM RECHARGEABLE BATTERY USING THE SAME}

The present invention relates to a nonaqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery using the electrolyte.

A battery is a device that converts chemical energy generated during electrochemical redox reaction of a chemical substance contained therein into electrical energy. A primary battery that should be discarded when energy in the battery is depleted according to its use characteristics. ) And rechargeable batteries that can be reused many times while still being charged.

Conventional miniaturized and slimmed lithium secondary batteries used in cellular phones, electronic notebooks, and watches have a lithium metal mixed oxide as a positive electrode active material, a raw material or metal lithium as a negative electrode active material, and an appropriate amount of lithium salt in an organic solvent. It is comprised as what melt | dissolved as electrolyte solution.

More specifically, a typical electrolyte component of the present lithium secondary battery is a mixture of polyethylene carbonate, ethylene carbonate, and the like of cyclic acid ether and dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, and the like of the chain carbonate ether, whereby dissolved LiPF ₆ I'm using one.

It is no exaggeration to say that the two newly developed electrolyte materials since the commercialization of lithium secondary batteries were methyl ethyl carbonate (MEC) adopted in 1993 and methyl propionate temporarily used by a specific battery manufacturer.

However, in recent years, there has been a demand for improvement of battery performance, particularly high temperature resistance, and development of a technology for adding a specific compound to an electrolyte solution in order to satisfy this problem has been conducted.

However, when a specific compound is added to the electrolyte to improve battery performance, the performance of some items of the battery performance can be expected, but there are problems such as reducing the performance of other items. For example, when the additive is added to the electrolyte, the high temperature anti-static property is improved, but there is a problem such as decrease in charge / discharge cycle performance.

An object of the present invention for solving the above problems is to improve the life characteristics of the charging and discharging cycles, lithium with trifluoromethyl fluorobenzene added to reduce the thickness increase rate of the battery at low temperature and to reduce the low-temperature discharge capacity The present invention provides a nonaqueous electrolyte solution for a secondary battery and a lithium secondary battery using the electrolyte solution.

Technical configuration of the present invention for solving the above technical problem is

Non-aqueous organic solvents;

Lithium salts;

Fluoro ethylene carbonate; And

It is characterized in that it comprises tri-fluoromethyl fluorobenzen (tri-fluoromethyl fluorobenzen) having the following formula.

The trifluoromethyl fluorbenzene may be 0.1 to 10% by weight. When 0.1 wt% or less of trifluoromethyl fluorbenzene is added, the high temperature leaving thickness ratio may increase, and when 10 wt% or more is added, the low-temperature discharge capacity may be drastically reduced.

The fluoro ethylene carbonate may be 0.1 to 10% by weight. When 0.1 wt% or less of fluoroethylene carbonate is added, there is no effect of improving lifespan, and when 10 wt% or more is added, the thickness of the battery increases rapidly at high temperature.

The non-aqueous organic solvent may be at least one solvent selected from the group consisting of carbonate, ether, ether and ketone.

The carbonate is dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylmethyl carbonate, ethylpropyl carbonate, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1, At least one solvent selected from the group consisting of 2-pentylene carbonate and 2,3-pentylene carbonate.

The lithium salt is LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₃ CF ₃ ) ₂ , LiC ₄ F ₉ SO ₃ , LiAlO ₄ , LiAlCl _{4 It} may be one or two or more selected from the group consisting of.

In another aspect, the present invention is a non-aqueous electrolyte for the lithium secondary battery;

A positive electrode comprising a positive electrode active material capable of reversibly intercalating and deintercalating lithium ions; And

And a negative electrode including a negative electrode active material capable of reversibly intercalating and deintercalating lithium ions.

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

In general, when the battery is discharged by a certain amount, the voltage thereafter is greatly reduced, and when the battery is discharged to a certain limit, the battery may be over-discharged to adversely affect the battery. Therefore, the voltage at which the limit is set so as not to adversely affect the battery is referred to as the discharge end voltage. The amount of discharge when a fully charged battery is discharged to a specified end voltage as a constant current is called the capacity of the battery. One of the losses that can affect this battery capacity is self discharge. Self-discharge is a function of reducing the capacity of the battery naturally within the battery without discharging to the outside, the higher the temperature of the battery occurs well.

In addition, when a battery in a fully charged state is stored at a high temperature of 60 ° C. or more, a phenomenon occurs in which the battery is swelled due to gas generation inside the battery. This phenomenon may affect the reversibility of the battery material due to charging and discharging, thereby lowering the life characteristics of the battery.

In the present invention, by adding trifluoromethyl fluorobenzene as the non-aqueous electrolyte additive, it is possible to increase the low-temperature discharge capacity of the secondary battery, and to improve the high-temperature standing characteristics and the life characteristics.

In general, it is the dielectric constant, viscosity, and the number of donors and acceptors that affect the properties of the electrolyte for lithium secondary batteries. Viscosity greatly affects the ion migration rate of the electrolyte, and the larger the polarity of the solvent and the higher the dielectric constant of the electrolyte. In the present invention, in order to increase the polarity, the methyl group of fluorobenzene is a strong substituent -NO ₂ , -NR ₃ ⁺ , -CF ₃ And CCl ₃ Trifluoromethyl fluorobenzene substituted with heavy trifluoromethyl group (-CF ₃ ) is used. Inert substituents remove the electron density from the benzene ring, making the electron affinity aromatic substitution reaction slower and more difficult than benzene itself.

Therefore, trifluoromethyl fluorbenzene contains strong inert substituents of trifluoromethyl group (-CF ₃ ) and may not be sensitive to changes in external conditions such as temperature.

The trifluoromethyl fluorobenzene has physical properties of a boiling point of 103.5 ° C., a melting point of −41.7 ° C., a molar volume of 127.1 cm 3 / mol, a molecular weight of 164.1, and a vapor pressure of 35.8 Torr (25 ° C.).

The electrolyte solution of the present invention also contains a non-aqueous organic solvent and a lithium salt. The lithium salt acts as a source of lithium ions in the battery to enable operation of the basic lithium battery, and the non-aqueous organic solvent serves as a medium through which Li ⁺ ions involved in the electrochemical reaction of the battery can move.

In the present invention, the lithium salt may be LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₃ CF ₃ ) ₂ , LiC ₄ F ₉ SO ₃ , LiAlO ₄ , LiAlCl ₄ , one or two or more selected from the group consisting of LiI can be used in combination. The concentration of the lithium salt is preferably used in the range of 0.6 to 2.0M, more preferably in the range of 0.7 to 1.6M. If the concentration of the lithium salt is less than 0.6M, the conductivity of the electrolyte decreases and the performance of the electrolyte deteriorates. If the concentration exceeds 2.0M, the viscosity of the electrolyte increases and the mobility of the lithium ion decreases.

The non-aqueous organic solvent may include a single or mixed carbonate, ether, ether or ketone. In the case of a carbonate-based solvent in the non-aqueous organic solvent, it is preferable to use a mixture of cyclic carbonate and chain carbonate. In this case, the cyclic carbonate and the chain carbonate are preferably used by mixing in a volume ratio of 1: 1 to 1: 9, and more preferably used by mixing in a volume ratio of 1: 1.5 to 1: 4. The performance of the electrolyte is superior to other volume ratios by mixing at the volume ratio.

As the cyclic carbonate, ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, etc. may be used. Can be. Among the high dielectric constant ethylene carbonate and propylene carbonate, ethylene carbonate has a high melting point and is mixed with other solvents. When graphite is used as a negative electrode active material, propylene carbonate having a low decomposition voltage is not used or the content is lowered.

As the chain carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylmethyl carbonate (EMC), ethylpropyl carbonate (EPC), etc. may be used. Among these, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate having low viscosity are mainly used.

As ether, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone, ε-caprolactone, etc. Tetrahydrrofuran, 2-methyltetrahydrofuran, dibutyl ether and the like may be used as the ether. As the ketone, polymethylvinyl ketone may be used.

The electrolytic solution of the present invention may further contain an aromatic hydrocarbon-based organic solvent in the carbonate-based solvent. As the aromatic hydrocarbon organic solvent, an aromatic hydrocarbon compound represented by Chemical Formula 3 may be used.

(3)

In the above formula, R is halogen or an alkyl group having 1 to 10 carbon atoms and q is an integer of 0 to 6. Specific examples of the aromatic hydrocarbon organic solvent may include benzene, fluorobenzene, bromobenzene, chlorobenzene, toluene, xylene, mesitylene, and the like, which may be used alone or in combination. When the volume ratio of carbonate solvent / aromatic hydrocarbon-based organic solvent in an electrolyte solution containing an aromatic hydrocarbon-based organic solvent is 1: 1 to 30: 1, characteristics of the electrolyte, such as stability, safety, and ion conductivity, which are generally required, are compared with those of other ratio compositions. great.

The lithium secondary battery of the present invention includes a positive electrode and a negative electrode.

The positive electrode includes a positive electrode active material capable of occluding and detaching lithium ions, and the positive electrode active material is preferably at least one selected from cobalt, manganese, nickel, and a composite metal oxide with lithium. 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.

The negative electrode includes a negative electrode active material capable of occluding and desorbing lithium ions, and examples of the negative electrode active material include carbon materials such as crystalline carbon, amorphous carbon, carbon composite, carbon fiber, lithium metal, alloys of lithium and other elements, and the like. Can be. Examples of the amorphous carbon include hard carbon, coke, mesocarbon microbead (MCMB) calcined at 1500 ° C. or lower, and mesophase pitch-based carbon fiber (MPCF). The crystalline carbon is a graphite-based material, specifically natural graphite, graphitized coke, graphitized MCMB, and graphitized MPCF. The carbonaceous material is preferably a material having an d002 interplanar distance of 3.35 to 3.38 Å and an Lc (crystallite size) of at least 20 nm by X-ray diffraction. Other elements constituting the alloy with lithium may be aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium or indium.

The positive electrode or the negative electrode 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 positive electrode current collector and the negative electrode current collector may be in the form of a foil or a mesh.

The binder is a material that plays a role of pasting the active material, mutual adhesion of the active material, adhesion with the current collector, buffering effect on the expansion and contraction of the active material, and the like, for example, polyvinylidene fluoride (PVdF), polyhexafluoro Copolymer of propylene-polyvinylidene fluoride (P (VdF / HFP)), poly (vinylacetate), polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, polyvinyl ether, poly ( Methyl methacrylate), poly (ethylacrylate), polytetrafluoroethylene, polyvinylchloride, polyacrylonitrile, polyvinylpyridine, styrene-butadiene rubber, acrylonitrile-butadiene rubber and the like. The content of the binder is 0.1 to 30% by weight, preferably 1 to 10% by weight, based on the electrode active material. When the content of the binder is too small, the adhesion between the electrode active material and the current collector is insufficient, and when the content of the binder is too high, the adhesion is improved, but the content of the electrode active material decreases by that amount, which is disadvantageous in increasing battery capacity.

The conductive material may be at least one selected from the group consisting of a graphite-based conductive agent, a carbon black-based conductive agent, a metal or a metal compound-based conductive agent as a material for improving electronic conductivity. Examples of the graphite conductive agent include artificial graphite and natural graphite, and examples of the carbon black conductive agent include acetylene black, ketjen black, denka black, thermal black, and channel. And black or the like, and examples of the metal or metal compound-based conductive agent include tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ , and perovskite such as LaSrMnO ₃ ( perovskite) substance. However, it is not limited to the conductive agents listed above.

The content of the conductive agent is preferably 0.1 to 10% by weight based on the electrode active material. When the content of the conductive agent is less than 0.1% by weight, the electrochemical properties are lowered, and when the content of the conductive agent is greater than 10% by weight, the energy density per weight decreases.

The thickener is not particularly limited as long as it can play a role of controlling the viscosity of the active material slurry. For example, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, or the like may 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 lithium secondary battery may include a separator that prevents a short circuit between the positive electrode and the negative electrode and provides a passage for lithium ions, and such separators include polypropylene, polyethylene, polyethylene / polypropylene, polyethylene / polypropylene / polyethylene, poly Polyolefin polymer membranes, such as propylene / polyethylene / polypropylene, or a multilayer of these, a microporous film, a woven fabric, and a nonwoven fabric can be used. Further, a film coated with a resin having excellent stability may be used for the porous polyolefin film.

As described in detail above, according to the present invention, when trifluoromethyl fluorbenzene is added as an electrolyte additive, the capacity is maintained according to charge / discharge cycle repetition, thereby improving the life characteristics and increasing the discharge capacity.

In addition, when the secondary battery is left at a high temperature, there is an effect of reducing the increase in battery thickness due to swelling.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings, examples, comparative examples, and experimental examples.

Example 1

LiCoO ₂ as a cathode active material, polyvinylidene fluoride (PVdF) as a binder and carbon as a conductive agent were mixed at a weight ratio of 92: 4: 4, and then dispersed in N-methyl-2-pyrrolidone to prepare a cathode slurry Respectively. 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. Synthetic graphite as a negative electrode active material, styrene-butadiene rubber as a binder, and carboxymethyl cellulose as a thickener were mixed in a weight ratio of 96: 2: 2, and then dispersed in water to prepare a negative electrode 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 film separator made of a polyethylene (PE) material having a thickness of 20 μm was put between the prepared electrodes and wound and compressed, and inserted into a can of a rectangular 463446 size. An electrolyte was injected into the rectangular can to prepare a lithium secondary battery. The electrolyte solution was dissolved in 1M LiPF ₆ in a 1: 1 electrolyte of 1.15M ethylene carbonate: ethyl methyl carbonate: diethyl carbonate, which is a non-aqueous organic solvent, and then 3% by weight of fluoroethylene carbonate and trifluoromethyl Electrolyte was prepared by adding 1% by weight of fluorobenzene (tri-fluoromethyl fluorobenzene).

Example 2

Except for adding 2% by weight of trifluoromethyl fluorbenzene in Example 1 it was all the same.

Example 3

Except for the addition of 3% by weight of trifluoromethyl fluorbenzene in Example 1 it was all the same.

Example 4

Except for the addition of 5% by weight of trifluoromethyl fluorbenzene in Example 1 it was all the same.

Example 5

Except for the addition of 10% by weight of trifluoromethyl fluorbenzene in Example 1 it was all the same.

Example 6

Except for the addition of 11% by weight of trifluoromethyl fluorbenzene in Example 1 it was all the same.

Comparative Example 1

In Example 1, 1M LiPF ₆ was dissolved in a basic electrolyte solution containing 1.15 M of ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate in a non-aqueous organic solvent. All were carried out in the same manner except adding an electrolyte by adding%.

Comparative Example 2

In Example 1, the electrolyte solution was dissolved in 1M LiPF ₆ in a 1: 1 electrolyte of 1M ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate, which are non-aqueous organic solvents, and then 3% by weight of fluorine ethylene carbonate and All were performed in the same manner except for preparing an electrolyte by adding 1% by weight of succinic anhydride.

Examples 1 to 6 to which trifluoromethyl fluorobenzene according to the present invention was added to an electrolyte solution, Comparative Example 1 to which fluoroethylene carbonate was added, and Standard capacity, lifetime characteristics, and Comparative Example 2 to which fluoroethylene carbonate and succinic anhydride were added The discharge capacity at 0 ° C., the increase rate of the battery thickness, and the discharge capacity at high temperatures are measured.

Experimental Example 1: Standard Capacity

Each cell was charged at 0.5 C / 4.2 V constant current-constant voltage for 3 hours and then the standard capacity was measured.

Experimental Example 2: Low Temperature Discharge Capacity

Each battery was charged at 0.5 C / 4.2 V constant current-constant voltage for 3 hours, left at 0 ° C. for 3 hours, and then discharged at 0.5 C / 3.2 V constant current-constant voltage to measure discharge capacity.

Experimental Example 3: Life Characteristics

Each cell was charged for 3 hours at 0.5 C / 4.2 V, constant current-constant voltage at room temperature, and after 10 minutes 1 C / 3 V constant current discharge. The charge and discharge was carried out for 500 cycles, and the capacity retention rate (%) at the 500th cycle was calculated.

Capacity retention rate (%) at 500 cycles = (discharge capacity at 500 cycles / discharge capacity at 5 cycles) × 100 (%)

Experimental Example 4: Battery thickness increase rate at high temperature

Each cell was charged for 3 hours at 0.5 C / 4.2 V, constant current-constant voltage, left at 85 ° C. for 10 days, and the percentage increase in thickness of the cell was calculated.

% Increase in battery thickness = (final thickness-initial thickness / initial thickness) × 100 (%)

Experimental Example 5: Discharge Capacity

Each battery was charged at 0.5 C / 4.2 V constant current-constant voltage for 3 hours, left for 2 hours, and discharged at 0.5 C / 3.2 V constant current-constant voltage to measure discharge capacity.

The results according to Experimental Examples 1 to 5 are shown in Table 1 and FIGS. 1 to 4.

Standard capacity Low temperature discharge capacity 500 capacity (%) High temperature
Thickness increase rate (%) Example 1 100% 90% 91% 6% Example 2 100% 89% 92% 5% Example 3 100% 88% 93% 5% Example 4 100% 87% 95% 4 % Example 5 100% 84% 96% 4 % Example 6 100% 78% 96% 4 % Comparative Example 1 100% 92% 62% 5% Comparative Example 2 100% 91% 88% 9%

As shown in Table 1, the results of the standard dose according to Experimental Example 1, both the Examples and Comparative Examples showed 100%.

As shown in Table 1 and Figure 4, the results of the 0 ° C discharge capacity according to Experimental Example 2, the low-temperature discharge capacity begins to decrease when more than 10% by weight of trifluoromethyl fluorobenzene is added, the present invention is trifluoromethyl fluorine It was determined that it was desirable to add 0.1 to 10% by weight of benzene. In addition, it was proved that the discharge capacity can be maintained at a low temperature when trifluoromethyl fluorbenzene was added as an electrolyte additive by showing a slight difference when comparing the embodiment according to the present invention with the comparative example.

As shown in Table 1 and FIG. 1, the results of the life characteristics according to Experimental Example 3, the lifespan according to 500 cycles of charging and discharging was repeated compared to the comparative example in which the examples according to the present invention were added fluoroethylene carbonate or fluoroethylene carbonate and succinic anhydride. It has been shown to increase the property to the highest.

As shown in Table 1 and FIG. 3, the results of the high temperature standing thickness ratio according to Experimental Example 4, the embodiment according to the present invention increased the thickness of the battery less at the time of high temperature standing compared to the comparative example. These results can be inferred that the cell suppresses swelling by reducing the gas generation inside the cell. In addition, gas generation inside the battery may affect the reversibility of the battery material due to charging and discharging, thereby reducing the battery life characteristics. By suppressing gas generation, the material of the battery is reversibly redoxed to increase the life characteristics. It can be inferred.

As a result of the discharge capacity according to Experimental Example 5, as shown in Figure 2, Example 5 according to the present invention and Comparative Example 2 with the addition of fluoroethylene carbonate was the highest, and Comparative Example 3 with the addition of succinic anhydride The discharge capacity was the lowest.

Summarizing the results of Experimental Examples 1 to 5, the lithium secondary battery to which trifluoromethyl fluorbenzene was added according to the present invention had excellent results in terms of life characteristics, battery thickness increase rate and discharge capacity at high temperatures. . Therefore, trifluoromethyl fluorbenzene can improve the performance of a lithium secondary battery as an electrolyte additive.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention . Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1 is a graph showing the life characteristics of a lithium secondary battery according to the present invention.

2 is a graph showing the discharge capacity of a lithium secondary battery according to the present invention.

3 is a graph showing a battery thickness increase rate at a high temperature of the lithium secondary battery according to the present invention.

4 is a graph showing low temperature (0 ° C.) discharge capacity of a lithium secondary battery according to the present invention;

Claims (7)

Non-aqueous organic solvents; Lithium salts; Fluoro ethylene carbonate; And A non-aqueous electrolyte solution for a lithium secondary battery comprising tri-fluoromethyl fluorobenzene having the following formula.

The non-aqueous electrolyte solution for lithium secondary batteries according to claim 1, wherein the trifluoromethyl fluorbenzene is 0.1 to 10 wt%. The non-aqueous electrolyte solution for lithium secondary batteries according to claim 1, wherein the fluoroethylene carbonate is 0.1 to 10 wt%. The nonaqueous electrolyte of claim 1, wherein the non-aqueous organic solvent is at least one solvent selected from the group consisting of carbonate, ether and ketone. The method of claim 4, wherein the carbonate is dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylmethyl carbonate, ethylpropyl carbonate, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3- A non-aqueous electrolyte solution for lithium secondary batteries, characterized in that at least one solvent selected from the group consisting of butylene carbonate, 1,2-pentylene carbonate and 2,3-pentylene carbonate. The lithium salt of claim 1 or 2, wherein the lithium salt is LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₃ CF ₃ ) ₂ , LiC ₄ F ₉ SO ₃ , LiAlO ₄ , LiAlCl ₄ , LiCl and LiI selected from the group consisting of A nonaqueous electrolyte solution for a lithium secondary battery, characterized in that. Non-aqueous electrolyte solution for a lithium secondary battery according to any one of claims 1 to 4; A positive electrode comprising a positive electrode active material capable of reversibly intercalating and deintercalating lithium ions; And A lithium secondary battery comprising a negative electrode including a negative electrode active material capable of reversibly intercalating and deintercalating lithium ions.

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