KR100407486B1 - Organic electrolytic solution and lithium battery employing the same - Google Patents

Abstract

The present invention provides an organic electrolyte solution comprising a lithium salt and a mixed organic solvent, wherein the mixed organic solvent includes a high dielectric constant solvent, a low boiling point solvent, at least one selected from a compound of Formula 1 and a compound of Formula 2 It relates to an organic electrolyte solution and a lithium battery comprising the same, the organic electrolyte of the present invention is excellent in ion conductivity, charge and discharge characteristics and flame resistance, the lithium battery employing the electrolyte solution of the present invention has a large battery capacity and progress cycle Even if it is possible to configure a high performance lithium battery with stable charge and discharge characteristics and swelling phenomenon is prevented.

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are independently of each other hydrogen, a linear alkyl group having 1 to 5 carbon atoms substituted with unsubstituted or halogen atoms and substituted with unsubstituted or halogen atoms It is selected from the group consisting of a cyclic alkyl group having 3 to 6 carbon atoms.

Description

Organic electrolytic solution and lithium battery employing the same

The present invention relates to a lithium battery, and more particularly, to a non-aqueous electrolyte and a lithium battery employing the same, which improves ion conductivity and flame retardancy, prevents swelling even when the temperature of the battery rises, and thus improves stability due to constant battery thickness. It is about.

As the weight reduction and the high functionalization of portable electronic devices such as video cameras, portable telephones, notebook PCs, and the like have progressed, many studies have been made on batteries used as driving power sources. In particular, the rechargeable lithium secondary battery has the highest energy density per unit weight and can be rapidly charged compared to the conventional lead storage battery, nickel-cadmium battery, nickel hydrogen battery, nickel zinc battery, etc. Hanaro R & D is actively progressing.

In the lithium secondary battery, as a cathode, transition metal compounds such as TiO ₂ , MoS ₂ , CoO ₂ , V ₂ O ₅ , FeS, NbS ₂ , MnO ₂ , or oxides thereof and lithium are used as active materials, and the anode As the furnace, lithium metal, an alloy thereof, or a carbon material is used as the active material.

In addition, the electrolyte is classified into a liquid electrolyte or a solid electrolyte according to the type of electrolyte. When a liquid electrolyte is used, many problems related to stability, such as a risk of fire due to leakage and breakage of the battery due to vaporization, are generated. In order to solve this problem, a method of using a solid electrolyte instead of a liquid electrolyte has been proposed. Solid electrolytes are generally researched in a lot of interest because there is no risk of leakage of electrolytes and they are easy to process. Among them, researches on polymer solid electrolytes are particularly active. Currently known polymer solid electrolytes can be divided into a completely solid form containing no organic electrolyte and a gel containing an organic electrolyte.

In general, lithium batteries are driven at high operating voltages, so existing aqueous electrolytes cannot be used. The main reason is that when the aqueous solvent is used, the anode lithium and the aqueous solution react violently. Therefore, an organic electrolyte solution in which lithium salt is dissolved in an organic solvent rather than an aqueous solution is used in a lithium battery. In this case, it is preferable to use an organic solvent having high ionic conductivity and low dielectric constant and low viscosity. Since organic solvents are difficult to obtain, a mixed solvent system of a high dielectric constant organic solvent and a low dielectric constant organic solvent or a mixed solvent system of a high dielectric constant organic solvent and a low viscosity organic solvent is used.

In US Pat. Nos. 6,114,070 and 6,048,637, efforts have been made to improve the ionic conductivity of organic solvents by mixing dimethyl carbonate or diethyl carbonate with ethylene carbonate or propylene carbonate as a mixed solvent of linear carbonate and cyclic carbonate.

However, these mixed solvents can usually be used below 120 ℃ but when the temperature is higher than the gas generated by the vapor pressure there was a problem that the battery is swelled and can not be used.

The technical problem to be achieved by the present invention is to provide an organic electrolyte solution having a high boiling point and almost no volatilization, further improving safety and flame retardancy and charging / discharging cycle characteristics.

Another object of the present invention is to provide a lithium battery employing the organic electrolyte.

1 is a view showing a comparison profile when the battery using the electrolyte solution of Example 4 and Comparative Example 2 of the present invention at 0.2C,

2 is a view showing a comparison profile when the battery using the electrolyte solution of Example 4 and Comparative Example 2 of the present invention when charged and discharged at 0.2C,

3 is a view showing a discharge capacity comparison of a battery using the electrolyte solution of Example 5 and Comparative Example 2 of the present invention,

4 is an NMR spectrum of 5-methyl-1,3-dioxolan-2-on prepared according to Synthesis Example 1 of the present invention,

5 is a view of measuring the stability of the electrolyte solution of Example 4 using the cyclic voltammetry method,

6 is a voltage-current graph showing a tendency of adsorption and desorption of lithium ions in the electrolyte solution of Example 4 of the present invention using a carbon anode.

In the first technical problem of the present invention is an organic electrolyte comprising a lithium salt and a mixed organic solvent,

The mixed organic solvent comprises a high dielectric constant solvent, a low boiling point solvent, and at least one selected from the compounds represented by Formulas 1 and 2 below.

<Formula 1>

<Formula 2>

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are independently of each other hydrogen, a linear alkyl group having 1 to 5 carbon atoms substituted with unsubstituted or halogen atoms and substituted with unsubstituted or halogen atoms It is selected from the group consisting of a cyclic alkyl group having 3 to 6 carbon atoms.

Preferably, at least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ is preferably a linear or cyclic alkyl group substituted with a fluorine group.

In addition, the second technical problem of the present invention is a cathode;

Anode; And

And a non-aqueous electrolyte comprising a lithium salt, a high dielectric constant solvent, a low boiling point solvent, and a mixed organic solvent including at least one selected from the compounds represented by Formulas 1 and 2.

<Formula 1>

<Formula 2>

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are independently of each other hydrogen, a linear alkyl group having 1 to 5 carbon atoms substituted with unsubstituted or halogen atoms and substituted with unsubstituted or halogen atoms It is selected from the group consisting of a cyclic alkyl group having 3 to 6 carbon atoms.

The organic electrolyte of the present invention is characterized by adding a compound of formula 1 and / or a compound of formula 2 to a mixture of a high dielectric constant solvent and a low boiling point solvent.

<Formula 1>

<Formula 2>

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are independently of each other hydrogen, a linear alkyl group having 1 to 5 carbon atoms substituted with unsubstituted or halogen atoms and substituted with unsubstituted or halogen atoms It is selected from the group consisting of a cyclic alkyl group having 3 to 6 carbon atoms.

In Formulas 1 and 2, specific examples of the unsubstituted linear alkyl group include methyl group, ethyl group, propyl group, and the like, and specific examples of the linear alkyl group substituted with halogen atom include trifluoromethyl group, pentafluoroethyl group, and the like. Specific examples of the cyclic alkyl group having 3 to 6 carbon atoms include a phenyl group and the like, and specific examples of the cyclic alkyl group having 3 to 6 carbon atoms substituted with a halogen atom include a fluorophenyl group and the like.

Preferably, at least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ is a cyclic group substituted with fluorine such as a linear alkyl group substituted with a fluorine group, such as a trifluoromethyl group, and a fluorophenyl group. It is preferable that it is an alkyl group.

In the organic electrolyte solution of the present invention, the total volume of the high dielectric constant solvent and the low boiling point solvent is 80 to 90%, and the total volume of at least one selected from the compounds represented by Formulas 1 and 2 is preferably 10 to 20%. If out of this range, the thickness of the battery is significantly inflated, and the ion conductivity and the charge and discharge characteristics of the battery are deteriorated. The mixing volume ratio of the high dielectric constant solvent and the low boiling point solvent is 30:70 to 50:50.

In addition, the high dielectric constant solvent is preferably ethylene carbonate, propylene carbonate, butylene carbonate, or gamma-butyrolactone, the low boiling point solvent is dimethyl carbonate, ethyl methyl carbonate. Preference is given to using diethyl carbonate, dipropyl carbonate, dimethoxyethane, diethoxyethane or fatty acid ester derivatives.

The compound of Formula 1 is 5-methyl-1,3-dioxolan-2-on (5-methyl-1,3-dioxolan-2-on) (R ₂ (or R ₃ ) is CH ₃ , R ₁ , R ₃ (or R ₂ ), when R ₄ is all H, 4,5-dimethyl-1,3-dioxolan-2-one (4,5-dimethyl-1,3-dioxolan-2- on) (R ₂ (or R ₃ ) is CH ₃ , R ₁ , R ₃ (or R ₂ ), where R ₄ is all H), 5-trifluoromethyl-1,3-dioxolane-2 -On (5-trifluoromethyl-1,3-dioxolan-2-on) (R ₁ , R ₂ (or R ₃ ) and R ₄ are all H, when R ₃ (or R ₂ ) is CF 3) and the like are preferred. More preferably, R ₁ , R ₄ are hydrogen groups and one of R ₂ and R ₃ is substituted with a trifluoromethyl group. And the compound of formula 2 is di-methyl-4-methyl-2,6-dioxoheptanedionate (when both R ₅ and R ₆ are methyl groups) , Di-ethyl-4-methyl-2,6-dioxoheptanedionate (when both R ₅ and R ₆ are ethyl groups), ethyl, methyl- 4-methyl-2,6-dioxoheptanedionate (Ethyl, methyl-4-methyl-2,6-dioxoheptanedionate) (when R ₅ is a methyl group and R ₆ is an ethyl group), methyl, trifluoromethyl- 4-methyl-2,6-dioxoheptanedionate (methyl, trifluoromethyl-4-methyl-2,6-dioxoheptanedionate) and the like, among which at least one of R ₅ and R ₆ is a methyl group and a trifluoromethyl group More preferably substituted.

The compound represented by Chemical Formula 1 serves to increase the flame retardancy without lowering the ionic conductivity, and the compound represented by Chemical Formula 2 serves to suppress decomposition of the electrolyte and absorb heat generated in the battery.

In addition, when using the compound of Formula 1 and Formula 2 together, the mixing volume ratio is 1: 9 to 9: 1, more preferably 3: 1.

In addition, the lithium salt may be used as long as it is commonly used in lithium batteries, and LiClO ₄ , LiCF ₃ SO ₃ , LiPF ₆ , LiN (CF ₃ SO ₂ ), LiBF ₄ , LiC (CF ₃ SO ₂ ) ₃ , Preference is given to at least one compound selected from the group consisting of LiN (C ₂ F ₅ SO ₂ ) ₂ . And it is preferable that the density | concentration of the lithium salt in electrolyte solution is about 0.5-2 M.

A lithium battery employing the electrolyte solution of the present invention and a manufacturing method thereof will be described. The lithium battery of the present invention is not particularly limited in form, and both lithium secondary batteries such as lithium ion batteries, lithium ion polymer batteries, and lithium primary batteries can be used.

First, a cathode active material composition is prepared by mixing a cathode active material, a conductive agent, a binder, and a solvent. The cathode active material composition is directly coated and dried on an aluminum current collector to prepare a cathode electrode plate. Alternatively, the cathode active material composition may be cast on a separate support, and then the film obtained by peeling from the support may be laminated on an aluminum current collector to manufacture a cathode electrode plate.

As the cathode active material, it is preferable to use LiCoO ₂ , LiMn _x O _2x , LiNi _1-x Mn _x O _2x (x = 1, 2) or the like as a lithium-containing metal oxide. Carbon black is used as the conductive agent, and vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene, and mixtures thereof are used. N-methylpyrrolidone, acetone, and the like are used as the solvent. At this time, the content of the cathode active material, the conductive agent, the binder, and the solvent is at a level commonly used in lithium batteries.

As in the case of manufacturing the cathode electrode plate described above, an anode active material composition is prepared by mixing an anode active material, a conductive agent, a binder, and a solvent, which is directly coated on a copper current collector or cast on a separate support and peeled from the support. The film is laminated on a copper current collector to obtain an anode plate. As the anode active material, lithium metal, lithium alloy, carbon material or graphite is used. In the anode active material composition, the conductive agent, the binder, and the solvent are used in the same manner as in the case of the cathode. In some cases, a plasticizer is further added to the cathode electrode active material composition and the anode electrode active material composition to form pores inside the electrode plate.

On the other hand, any separator can be used as long as it is commonly used in lithium batteries. As long as it is conventionally used in a lithium battery, it can use all, and it is especially preferable that it is low resistance with respect to the ion migration of electrolyte, and excellent electrolyte solution moisture-absorbing ability. More specifically, the material selected from glass fiber, polyester, teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), and combinations thereof may be nonwoven or woven. In more detail, a lithium ion battery uses a windable separator made of a material such as polyethylene or polypropylene, and a lithium ion polymer battery uses a separator having excellent organic electrolyte impregnation ability. Such a separator can be manufactured according to the following method.

That is, a separator composition is prepared by mixing a polymer resin, a filler, and a solvent.

The separator composition is directly coated and dried on an electrode to form a separator film, or the separator composition is cast and dried on a support, and then the separator film peeled from the support is deposited on the electrode. It can be formed by lamination.

The polymer resin is not particularly limited, but any material used for the binder of the electrode plate may be used. Vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate and mixtures thereof can be used here. Among them, vinylidene fluoride-hexafluoropropylene copolymer having a hexafluoropropylene content of 8 to 25% by weight is used.

A separator is disposed between the cathode electrode plate and the anode electrode plate as described above to form a battery structure. The battery structure is wound or folded, placed in a cylindrical battery case or a square battery case, and then the organic electrolyte solution of the present invention is injected to complete a lithium ion battery. Alternatively, the battery structure is stacked in a bi-cell structure, and then impregnated in the organic electrolyte, and the resultant is placed in a pouch and sealed to complete a lithium ion polymer battery.

Hereinafter, the present invention will be described in detail with reference to the following Examples, but the present invention is not necessarily limited thereto.

Synthesis Example 1

2-methyl-1,3-propanediol (36 g, 0.40 mol), dimethyl carbonate (72 g, 0.80 mol) and tetra-n-butylammonium bromide (0.40) while purging nitrogen gas in a round bottom flask equipped with a magnetic stirrer g, 0.0040 mol) and the mixture was heated at 120 ° C. for 6 hours. The mixture was transferred to a 500 mL round bottom flask and distilled at atmospheric pressure to remove methanol. The reaction mixture was analyzed by gas chromatography (GC). Analysis showed that about 90% of the starting material 2-methyl-1,3-propanediol was converted. For complete conversion of unreacted 2-methyl-1,3-propanediol, dimethyl carbonate (20 g, 0.22 mol) was added to the reaction mixture and reacted vigorously for 1 hour, followed by distillation at atmospheric pressure to remove methanol. It was. After removing methanol as described above, the reaction product was purified by vacuum distillation (0.5torr). As a result of vacuum distillation, 37 g of 5-methyl-1,3-dioxolan-2-one (boiling point: 74 to 75 ° C, purity: 99%) was obtained.

The structure of 5-methyl-1,3-dioxolan-2-one thus formed is as shown in the NMR spectrum of FIG. 4. Referring to this, the two peaks in the vicinity of 1.0ppm represents a methyl group, and the peak at 4.1ppm represents two carbons of the 4th and 6th carbon sites.

Synthesis Example 2

The same procedure as in Synthesis Example 1 was carried out except that 0.22 mol of 2-methyl-1,3-propanediol, dimethyl carbonate (0.44 mol), and tetramethylammonium compound (0.0022 mol) were added thereto and reacted in a nitrogen atmosphere. Di-methyl-4-methyl-2,6-dioxoheptanedionate (Di-methyl-4-methyl-2,6-dioxoheptanedionate) was prepared. Analysis of the reaction mixture using GC showed that about 75% of the starting material was converted.

<Example 1>

95 wt% of LiCoO ₂ , ₂ wt% of PVdF as a binder, and 3 wt% of carbon conductive agent to improve the transport of electrons were added thereto, followed by addition of N-methylpyrrolidone (NMP) (100 ml) and ceramic balls, and this mixture In a 200 ml plastic bottle and knead well for 10 hours. Then, cast a 250 μm-thick doctor blade on a 15 μm-thick aluminum foil to obtain a cathode electrode, place it in an oven at about 110 ° C., dry it for about 12 hours, and let NMP fly off completely. Using the method, a cathode having a thickness of 95 µm was obtained.

The anode active material was mixed well by adding NMP to PVdF 7wt% as a binder to 93wt% graphite MCMB 2528 (Osaka Gas Co.), and then kneading well for about 10 hours. The mixture was cast on a copper foil having a thickness of 19 μm with a doctor blade spaced 300 μm to obtain an anode electrode, which was then placed in a 90 ° C. oven like a cathode, and dried for about 10 hours to allow NMP to be completely blown off. The electrode plate was roll-pressed again to obtain an anode electrode having a thickness of 120 µm.

As a separator, a polyethylene / polypropylene microporous membrane (US Hoest Cellanese) having a thickness of 20 μm was used.

An electrode structure was manufactured using the cathode, the anode, and the separator. The electrode structure was accommodated in a battery case and an electrolyte was injected to prepare a capacity 800mAh square battery. At this time, a total of 10 batteries were prepared for the present electrolyte composition experiment.

Examples of the electrolyte include 40% by volume of ethylene carbonate, 40% by volume of dimethyl carbonate, 15% by volume of 5-methyl-1,3-dioxolane-2-one, and di-methyl-4-methyl-2,6-dioxoheptane. After mixing 5% by volume of dionate, 1M LiPF ₆ was used as the lithium salt.

<Example 2>

As the organic electrolyte, the same method as in Example 1, except that 40 vol% of ethylene carbonate, 40 vol% of diethyl carbonate and 20 vol% of 5-methyl-1,3-dioxolane-2-one were used. Was carried out.

<Example 3>

As the organic electrolyte, the same method as in Example 1, except that 40 vol% of ethylene carbonate, 50 vol% of diethyl carbonate, and 10 vol% of 5-methyl-1,3-dioxolane-2-one were used. Was carried out.

<Example 4>

As the organic electrolyte solution, except that 40 vol% of ethylene carbonate, 20 vol% of diethyl carbonate, 20 vol% of dimethyl carbonate and 20 vol% of 5-methyl-1,3-dioxolan-2-one were used, It carried out by the same method as Example 1.

Example 5

In the composition for forming a polymer electrolyte, the monomer solution for forming a VdF-HFP copolymer (15 g) was placed in a 250 ml bottle containing 100 ml of the electrolyte of Example 4, and then left in an oven at 80 ° C. for about 1 hour. Shake it vigorously to prepare it by melting completely.

Cathode and anode were prepared in the same manner as in Example 1, and then the cathode was spread on a glass plate, and the polymer electrolyte forming composition was poured thereon, cast into a doctor blade having a thickness of 200 μm, and left in a dry atmosphere for about 1 minute. This was made to form.

The anode was cast in the same manner as the cathode on the glass plate to form a composition for forming a polymer electrolyte to obtain an anode coated on the surface of the polymer electrolyte. Thereafter, the cathode and the anode were stacked with a gap of about 5 cm and wound into a jelly roll type, and then pressurized with a hot press of 96 N / cm ² for about 1 minute to obtain a rectangular lithium polymer battery.

Comparative Example 1

As an organic electrolyte solution, it carried out by the same method as Example 1 except having used the mixture of 40 volume% of ethylene carbonate, 40 volume% of dimethyl carbonate, and 20 volume% of methyl ethyl carbonate.

Comparative Example 2

The organic electrolytic solution was carried out in the same manner as in Example 1, except that 30 vol% of ethylene carbonate, 55 vol% of methyl ethyl carbonate, 5% of propylene carbonate, and 10 vol% of fluorobenzene were used.

The ion conductivity of the organic electrolyte of Examples 1-5 and Comparative Examples 1-2 was measured at 10 kHz using an impedance (Solartron 1260) analyzer, and the results are shown in Table 1 below. In addition, to evaluate the flame retardancy of the electrolyte solution, the filter paper having a width of 15 mm, a length of 320 mm, and a thickness of 200 μm was dipped into the electrolyte for 10 minutes, and each test paper was held with a pin and stood vertically for 3 minutes, so that no extra electrolyte was completely removed. made. Then, in the state impregnated with the flame-retardant electrolyte solution, the filter paper was placed on the support of the sample stand at 25 mm intervals and fixed horizontally, and the sample stand was burned in a well-ventilated hood to measure the burning rate.

On the other hand, to determine the degree of swelling of the battery after charging and discharging at 0.2C, and then again charging and discharging at 2C and measured the thickness of the battery using a digital caliper to obtain the results shown in Table 1.

Electrolyte sample Ion Conductivity (10 ^-3 S / cm) Burning speed (mm / min) Swelling accuracy (mm) Example 1 10.3 1.1 6.28 Example 2 10.1 1.5 6.34 Example 3 10.7 1.7 6.30 Example 4 10.5 2.4 6.29 Comparative Example 1 11.2 17.7 6.53 Comparative Example 2 10.3 3.5 6.37

As shown in Table 1, the electrolyte of Examples 1 to 4 is slightly inferior to the ion conductivity of Comparative Example, but is applicable to conventional lithium ion batteries and lithium polymer batteries, that is, ion conductivity, that is, ion conductivity of 8.0 × 10 −3 mS / cm or more. It can be seen that the value is satisfied. In addition, the electrolyte solution of Examples 1-4 is improved in flame retardancy compared to the case of Comparative Example 1-2, and particularly, even after repeated charging and discharging, swelling does not occur and maintains a constant battery thickness, thereby showing an effect of improving stability. In addition, the charge and discharge profile results shown in FIGS.

1 to 3 show stable battery characteristics because there is almost no change in charge / discharge profile when using the electrolyte according to Examples 4 and 5 and the battery using the electrolyte of Comparative Example 2.

5 shows that when the electrolyte solution of Example 4 was applied to a battery by using the cyclic voltammetry method, stable battery characteristics were shown in a region of 2.5 V to 4.2 V, which is the use period of the battery.

FIG. 6 is an experiment to check whether the redox is well performed on the anode surface of the battery to which the electrolyte solution of Example 4 is added, as shown in the drawing. It can be seen that.

The organic electrolyte according to the present invention has excellent ion conductivity, charge / discharge characteristics, and flame resistance. When the organic electrolyte solution is employed, not only the battery has a large capacity and exhibits stable charge / discharge characteristics even when the cycle proceeds, but also the swelling of the battery temperature increases. This can be prevented and a lithium battery having excellent stability can be produced.

Claims (8)

In an organic electrolyte solution containing a lithium salt and a mixed organic solvent, The mixed organic solvent, With high dielectric constant solvent. An organic electrolyte comprising a low boiling point solvent and at least one selected from compounds of Formulas 1 and 2: <Formula 1> <Formula 2> Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are independently of each other hydrogen, a linear alkyl group having 1 to 5 carbon atoms substituted with unsubstituted or halogen atoms and substituted with unsubstituted or halogen atoms It is selected from the group consisting of a cyclic alkyl group having 3 to 6 carbon atoms. The organic electrolyte solution of claim 1, wherein the total volume of the high dielectric constant solvent and the low boiling point solvent is 80 to 90%, and the total volume of at least one selected from the compounds of Formula 1 or Formula 2 is 10 to 20%. . The method of claim 1, wherein the mixing volume ratio of the compound of Formula 1 and the compound of Formula 2 is 1: 9 to 9: 1, and the mixing volume ratio of the high dielectric constant solvent and the low boiling point solvent is 30:70 to 50:50 Organic electrolyte. The organic electrolytic solution according to claim 1 or 2, wherein the high dielectric constant solvent is selected from the group consisting of ethylene carbonate, propylene carbonate, butylene carbonate, and gamma butyrolactone. The method of claim 1 or 2, wherein the low boiling point solvent is dimethyl carbonate, ethyl methyl carbonate. An organic electrolyte solution selected from the group consisting of diethyl carbonate, dipropyl carbonate, dimethoxyethane, diethoxyethane and fatty acid ester derivatives. The compound according to claim 1 or 2, wherein the compound of formula 1 is 5-methyl-1,3-dioxolan-2-one, 4,5-methyl-1,3-dioxoran-2-one or An organic electrolytic solution, which is 5-trifluoromethyl-1,3-dioxolan-2-one. 3. The compound of claim 1, wherein the compound of Formula 2 is di-methyl-4-methyl-2,6-dioxoheptanedionate, di-ethyl-4-methyl-2,6-dioxoheptanedio Nate or ethyl, methyl-4-methyl-2,6-dioxoheptanedionate, or methyl, trifluoromethyl-4-methyl-2,6-dioxoheptanedionate, The organic electrolyte solution characterized by the above-mentioned. Cathode; Anode; And A non-aqueous electrolyte solution comprising a lithium salt, a high dielectric constant solvent, a low boiling point solvent, and a mixed organic solvent including at least one selected from the compounds represented by Formulas 1 and 2; <Formula 1> <Formula 2> Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are independently of each other hydrogen, a linear alkyl group having 1 to 5 carbon atoms substituted with unsubstituted or halogen atoms and substituted with unsubstituted or halogen atoms It is selected from the group consisting of a cyclic alkyl group having 3 to 6 carbon atoms.