KR20190119885A - Electrolyte composition for lithium secondary battery and a lithium secondary battery comprising the same - Google Patents

Abstract

The present invention relates to an electrolyte composition for a lithium secondary battery and a lithium secondary battery comprising the same. More specifically, the present invention relates to an electrolyte composition which enables the use of a carbon material (graphite) by replacing a conventional lithium metal having a problem of generating a dendrite as a negative electrode while providing a reversible positive electrode reaction stably while maintaining a conventional positive electrode system in a lithium-air secondary battery.

Description

Electrolytic composition for a lithium secondary battery and a lithium secondary battery comprising the same {Electrolyte composition for lithium secondary battery and a lithium secondary battery comprising the same}

The present invention relates to an electrolyte composition for a lithium secondary battery and a lithium secondary battery comprising the same, and more particularly, to stably provide a reversible positive reaction while maintaining a conventional positive electrode system in a lithium-air secondary battery. The present invention relates to an electrolyte composition capable of using a carbon material (graphite) by replacing an existing lithium metal having a problem of generating a dendrite as a negative electrode, and a lithium secondary battery including the same.

Conventionally, lithium ion secondary batteries have been used as main power storage devices in fields such as mobile phones, notebook computers, and electric vehicles, but in recent years, smaller and lighter secondary batteries are required. Therefore, research into next-generation secondary batteries having high energy densities exceeding lithium ion secondary batteries has been actively conducted, and various attempts have been made.

Among them, the lithium-air secondary battery uses oxygen in the air as the positive electrode active material and lithium metal as the negative electrode active material. Therefore, the lithium-air secondary battery does not need to contain oxygen as the positive electrode active material in the battery, thereby exhibiting a very large discharge capacity in theory. As a post lithium ion secondary battery, it is expected to be applied to next-generation electric vehicles and power storage systems of solar or wind power generation facilities.

In a lithium-air secondary battery, the following oxygen reduction (discharge) and oxygen generation (charge) occur at the positive electrode, and lithium dissolve (discharge) and precipitation (charge) occur at the negative electrode, thereby enabling charge and discharge.

However, when the electrolyte solvent used in the lithium-air secondary battery is unstable with radicals, Li ₂ O ₂ is not generated and the decomposition reaction of the electrolyte solvent occurs, and thus, reversibly stable charging and discharging cannot be performed. . Thus, a stable electrolyte solvent for the radicals is required for the reversible anodic reaction of lithium-air secondary batteries.

1,2-dimethoxyethane, acetonitrile, ionic liquids and the like have been studied as electrolyte solvents for reversible anodic reactions. However, acetonitrile is vulnerable to reduction and cannot withstand the potential of lithium ion insertion, 1,2-dimethoxyethane is inserted into the cathode together with lithium ions, and similarly, cationic species are inserted into the cathode in ionic liquids. There is a known problem.

Furthermore, even if the problem of reversibility in the anodic reaction is solved, when lithium metal is used as the negative electrode, metallic lithium precipitates in the dendritic phase (dendrite) during charging, and the dendrite grows to the positive electrode by repeating charging and discharging. There is a problem of shorting.

In lithium ion secondary batteries, it is known that the problem of dendrite precipitation in the negative electrode can be solved by using a carbon material such as graphite as the negative electrode active material. However, in the case of lithium-air secondary batteries, in the electrolyte solvent (for example, 1,2-dimethoxyethane, acetonitrile, ionic liquid, etc.) required for the reversible reaction in the positive electrode using oxygen as the positive electrode active material, the negative electrode carbon It has generally been considered that it cannot cause the insertion / removal of reversible lithium ions into the material, and therefore the negative electrode formed of the carbon material in the lithium-air secondary battery has been excluded from consideration.

Therefore, in lithium-air secondary batteries, there is a demand for the development of a technology capable of stably maintaining a reversible positive electrode reaction and solving the problem of dendrite precipitation at the negative electrode.

Japanese Laid-Open Patent No. 2016-122657 Korean Patent Publication No. 10-2017-0061692

The present invention is to solve the problems of the prior art as described above, while providing a reversible positive reaction stably while maintaining the existing positive electrode system in a lithium-air secondary battery, while having a problem of generating dendrite as a negative electrode It is an object of the present invention to provide an electrolyte composition and a lithium secondary battery including the same, which replaces lithium metal and enables the use of a carbon material (graphite).

The present invention to solve the above technical problem, a non-aqueous electrolyte solvent containing diether of anhydrosugar alcohol; And a lithium salt, wherein the content of diethan of the anhydrosugar alcohol in 100% by weight of the non-aqueous electrolyte solvent is greater than 15% by weight, and the molar concentration of the lithium salt in the composition is greater than 0.4 M. To provide.

According to another aspect of the invention, the anode; cathode; Separator; And an electrolyte solution, characterized in that the electrolyte solution comprises an electrolyte composition according to the present invention, a lithium-air secondary battery is provided.

The electrolyte composition according to the present invention stably provides a reversible positive reaction to a lithium-air secondary battery, and enables the use of a carbon material as a negative electrode in a lithium-air battery, which has been difficult to realize in a conventional electrolyte solvent system. do. This reverses the conventional technical knowledge that it is difficult to apply a carbon material as a negative electrode in an ether solvent system such as 1,2-dimethoxyethane, which has been generally applied when oxygen is used as a positive electrode active material, and is a conventional lithium ion battery and lithium-air. It can be said that the advantages of both batteries were expressed.

In addition, in the prior art (Japanese Patent Laid-Open No. 2016-122657), in order to realize the advantages of both the lithium ion battery and the lithium-air battery, the expensive lithium salt is used in a non-aqueous solvent at a level exceeding 2.2 M. However, the problem of economical remarkably inferior occurs, but the present invention by using the anhydrosugar alcohol diether in a specific content range in a non-aqueous solvent, it is possible to implement the performance as a battery even if the concentration of the lithium salt to more than 0.4 M.

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

The non-aqueous electrolyte solvent contained in the electrolyte composition of the present invention contains a diether of anhydrosugar alcohol.

The anhydrosugar alcohol refers to any substance obtained by removing one or more water molecules from a compound obtained by adding hydrogen to a reducing end group of a saccharide, commonly called hydrogenated sugar or sugar alcohol. do.

The anhydrosugar alcohol may be dianhydrohexitol which is a dehydration product of hexitol, more preferably isosorbide (1,4: 3,6-dianhydrosorbitol), isomannide (1,4: 3,6 Dianhydromannitol), isoidide (1,4: 3,6- dianhydroiditol) or mixtures thereof, most preferably isosorbide.

The diether of the anhydrosugar alcohol may specifically be a diC ₁ -C ₄ alkyl ether of anhydrosugar alcohol, more specifically the diC ₁ -C ₂ alkyl ether of anhydrosugar alcohol, and more specifically It may be a diC ₁ alkyl ether of anhydrosugar alcohol (ie, dimethyl ether of anhydrosugar alcohol).

In a preferred embodiment of the present invention, dimethyl isosorbide (DMI) is used as diether of the anhydrosugar alcohol.

In the electrolyte composition of the present invention, the content of diether of the anhydrosugar alcohol in 100% by weight of the non-aqueous electrolyte solvent is more than 15% by weight. If the content of the diether of the anhydrosugar alcohol in the non-aqueous electrolyte solvent is 15% by weight or less, there is a problem in that the retention rate is significantly reduced with respect to the initial discharge capacity as the secondary battery including the electrolyte composition is repeatedly charged and discharged.

More specifically, the content of the diether of the anhydrosugar alcohol in 100% by weight of the non-aqueous electrolyte solvent may be 16% by weight, 17% by weight, 18% by weight, 19% by weight or 20% by weight or more. There is no limit to the upper limit of the diether content of the anhydrosugar alcohol in the non-aqueous electrolyte solvent, and thus the upper limit may be 100% by weight (ie, the non-aqueous electrolyte solvent may consist only of the diether of the anhydrosugar alcohol).

The non-aqueous electrolyte solvent contained in the electrolyte composition of the present invention may further include an organic solvent other than the diether of the anhydrosugar alcohol.

As an organic solvent other than the diether of the anhydrosugar alcohol which can be used further by this invention, it is aprotic and non-carbonate organic solvents, such as acetonitrile, propionitrile, acrylonitrile, malononitrile, etc. Nitrile; 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, 2,2-dimethyl-1,3 Ethers such as dioxolane, 2-methyltetrahydropyran, 2-methyltetrahydrofuran and crown ether; Amides such as formamide, N, N-dimethylformamide, N, N-dimethylacetamide, and N-methylpyrrolidone; Isocyanates such as isopropyl isocyanate, n-propyl isocyanate and chloromethyl isocyanate; Esters such as methyl acetate, ethyl acetate, propyl acetate, methyl propionate, methyl formate, ethyl formate, vinyl acetate, methyl acrylate and methyl methacrylate; Epoxy compounds such as glycidyl methyl ether, epoxy butane and 2-ethyloxirane; Oxazoles such as oxazole, 2-ethyloxazole, oxazoline and 2-methyl-2-oxazoline; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Acid anhydrides such as acetic anhydride and propionic anhydride; Sulfones such as dimethyl sulfone and sulfolane; Sulfoxides such as dimethyl sulfoxide; Nitroalkanes such as 1-nitropropane and 2-nitropropane; Furan, such as furan and furfural; cyclic esters such as γ-butyrolactone, γ-valerolactone, and δ-valerolactone; Aromatic heterocyclic compounds such as thiophene and pyridine; Heterocyclic compounds such as tetrahydro-4-pyron, 1-methylpyrrolidine, and N-methylmorpholine; Or phosphate esters such as trimethyl phosphate and triethyl phosphate, and the like, and preferably 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 1,3 Ethers such as dioxane, 1,4-dioxane, 2,2-dimethyl-1,3-dioxolane, 2-methyltetrahydropyran, 2-methyltetrahydrofuran and crown ether; Nitriles such as acetonitrile, propionitrile, acrylonitrile and malononitrile; Sulfoxides such as dimethyl sulfoxide; cyclic esters such as γ-butyrolactone, γ-valerolactone, and δ-valerolactone; Or one or more selected from the group consisting of sulfones such as sulfolane, and more preferably 1,2-dimethoxyethane, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, γ butyrolactone, sulfolane, or these It may be a mixture of two or more, but is not limited thereto.

When an organic solvent other than the diether of such anhydrosugar alcohol is used in the present invention, the amount thereof is 85 wt% or less (for example, 0.1 to 85 wt%) based on 100 wt% of the non-aqueous electrolyte solvent, and more specifically, As may be 0.1 to 80% by weight, but is not limited thereto.

The lithium salt included in the electrolyte composition of the present invention is LiSCN, LiBr, LiI, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiCH ₃ SO ₃ , LiCF ₃ SO ₃ , LiClO ₄ , LiBPh ₄ , LiC (CF ₃ 1 type selected from the group consisting of SO ₂ ) ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (SFO ₂ ) ₂ , or LiN (CF ₃ CF ₂ SO ₂ ) ₂ The compound may be, but is not limited thereto. Ph here means phenyl.

In the electrolyte composition of the present invention, the molar concentration of the lithium salt exceeds 0.4 M. If the lithium salt molar concentration in the electrolyte composition is 0.4 M or less, there is a problem that the initial (first time) discharge capacity of the secondary battery containing the electrolyte composition is significantly reduced.

More specifically, the lithium salt molar concentration in the electrolyte composition may be at least 0.42 M, at least 0.44 M, at least 0.46 M, at least 0.48 M or at least 0.5 M. The upper limit of the lithium salt molar concentration is not particularly limited, and may be, for example, 5 M or less, 4.5 M or less, 4 M or less, 3.5 M or less, 3 M or less, 2.5 M or less, or 2 M or less, preferably 2 M or less. Can be. When the molar concentration of the lithium salt exceeds 2 M, it may cause a cost increase without any effect of increasing the molar concentration.

In addition to the electrolyte solvent component and the lithium salt component described above, the electrolyte composition of the present invention may further contain other components, for the purpose of improving the function, if necessary.

Examples of the other components include an overcharge preventing agent, a dehydrating agent, a deoxidizer, an agent for improving properties for improving capacity retention characteristics and cycle characteristics after high temperature storage, which are commonly known in the art.

Examples of the overcharge inhibitor include partial hydrides of biphenyl, alkylbiphenyl, terphenyl and terphenyl; Aromatic compounds such as cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenylether and dibenzofuran; Partial fluorides of such aromatic compounds such as 2-fluorobiphenyl, o-cyclohexyl fluorobenzene and p-cyclohexyl fluorobenzene; Fluorine-containing anisole compounds such as 2,4-difluoroanisole, 2,5-difluoroanisole, and 2,6-difluoroanisole, but are not limited thereto. An overcharge inhibitor may be used individually by 1 type, and may use 2 or more types together.

When the electrolyte composition of the present invention includes an overcharge inhibitor, the content thereof may be, for example, 0.01 to 5% by weight based on the total weight of the electrolyte composition. When the content of the overcharge inhibitor in the electrolyte composition is 0.01% by weight or more, the rupture and ignition of the lithium-air secondary battery due to the overcharge can be more easily suppressed, and the lithium-air secondary battery can be used more stably.

Examples of the dehydrating agent include, but are not limited to, molecular sieves, mirabilite, magnesium sulfate, calcium hydride, sodium hydride, potassium hydride and lithium aluminum hydride. A dehydrating agent may be used individually by 1 type, and may use 2 or more types together.

In one embodiment, a non-aqueous solvent used in the electrolyte composition of the present invention may be used after dehydration with the dehydrating agent and then purified. In addition, it is also possible to use a non-aqueous solvent which is performed only by dehydration by the dehydrating agent, and not purified.

As a characteristic improvement agent for improving the capacity retention characteristic and cycling characteristics after the said high temperature storage, for example, succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride Carboxylic acid anhydrides such as diglycolic acid anhydride, cyclohexanedicarboxylic acid anhydride, cyclopentane tetracarboxylic dianhydride, and phenylsuccinic anhydride; Ethylene sulfite, 1,3-propanesultone, 1,4-butanesultone, methyl methanesulfonate, busulfan, sulfolane, sulfolene, dimethyl sulfone, diphenyl sulfone, methylphenyl sulfone, dibutyl disulfide, dicyclohexyl disulfide Sulfur-containing compounds such as tetramethylthiuram, monosulfide, N, N-dimethylmethane sulfonamide and N, N-diethylmethane sulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methyl succinimide Nitrogen-containing compounds; Hydrocarbon compounds such as heptane, octane and cycloheptane; And fluorine-containing aromatic compounds such as fluorobenzene, difluorobenzene, hexafluorobenzene, and benzotrifluoride, but are not limited thereto. These characteristics improvement preparations may be used individually by 1 type, and may use 2 or more types together.

When the electrolyte composition of the present invention includes the property improving aid, the content thereof may be, for example, 0.01 to 5 wt% based on the total weight of the electrolyte composition.

According to another aspect of the invention, the anode; cathode; Separator; And an electrolyte solution, characterized in that the electrolyte solution comprises an electrolyte composition according to the present invention, a lithium-air secondary battery is provided.

In the lithium-air secondary battery of the present invention, the negative electrode may be an electrode including a negative electrode active material capable of electrochemically absorbing and releasing lithium ions.

As the negative electrode active material, a negative electrode active material for a known lithium ion secondary battery may be used. For example, a carbon material such as natural graphite (graphite), highly oriented graphite (HOPG), or amorphous carbon may be used. Can be. In addition, another example of the negative electrode active material, lithium metal; Or lithium element-containing metal compounds such as alloys containing lithium element, metal oxides, metal sulfides or metal nitrides.

As an alloy containing the said lithium element, a lithium aluminum alloy, a lithium tin alloy, a lithium lead alloy, or a lithium silicon alloy is mentioned, for example. A metal oxide containing the element lithium, for example, there may be mentioned lithium titanium oxide (Li ₄ Ti ₆ O _12, etc.). As a metal nitride containing the said lithium element, lithium cobalt nitride, lithium iron nitride, lithium manganese nitride, etc. are mentioned, for example. The above-mentioned negative electrode active material can be used individually by 1 type, or can use 2 or more types together.

Preferably, the negative electrode active material may be a carbon material such as graphite, and more preferably, the negative electrode active material may be graphite which is surface-modified with an amorphous carbonaceous material as compared with graphite or graphite.

The negative electrode may contain only a negative electrode active material, or may be in a form containing at least one of a conductive material and a binder (binder) in addition to the negative electrode active material and attached to a negative electrode current collector as a negative electrode material. For example, when the negative electrode active material is thin, it may be a negative electrode containing only a negative electrode active material, and when the negative electrode active material is a powder type, it may be a negative electrode having a negative electrode active material and a binder (binder). In order to form a negative electrode using a powdered negative electrode active material, the doctor blade method, the shaping | molding method by a compression press, etc. can be used.

As said conductive material, organic conductive materials, such as conductive fibers, such as a carbon material and metal fiber, metal powders, such as copper, silver, nickel, and aluminum, and a polyphenylene derivative, can be used, for example. As the carbon material, graphite, soft carbon, hard carbon, carbon black, Ketjen black, acetylene black, graphite, activated carbon, carbon nanotubes, carbon fibers and the like can be used. In addition, mesopolar carbon obtained by calcining a synthetic resin containing an aromatic ring, petroleum pitch, or the like can also be used.

As the binder, for example, polyvinylidene difluoride (PVDF), ethylene-propylene-diene terpolymer, styrene-butadiene rubber (SBR)), acrylonitrile-butadiene rubber, fluoro elastomers, polyvinyl acetate, polymethyl methacrylate, polyethylene, nitro Cellulose (nitrocellulose), carboxymethyl cellulose, or a mixture of two or more thereof.

As the negative electrode current collector, a rod-like body, a plate-like body, a thin body, or a network body mainly composed of copper, nickel, aluminum, stainless steel, or the like can be used.

In the lithium-air secondary battery of the present invention, the positive electrode may be an electrode including a positive electrode active material. It is preferable that oxygen is used as the positive electrode active material.

The positive electrode may be one commonly used as a positive electrode of a lithium-air secondary battery, and may include a conductive material having a pore through which oxygen and lithium ions may move, and may contain a binder. It may also contain a catalyst that promotes the oxidation / reduction reaction of oxygen.

As the conductive material and the binder (binder), those same as those used for the negative electrode can be used.

As a catalyst for promoting the reduction / oxidation reaction of oxygen, MnO ₂ , Fe ₂ O ₃ , NiO, CuO, Pt, or Co may be used.

As the cathode current collector, carbon cloth, carbon paper, carbon felt, or the like, which is carbon-based, may be used to increase oxygen diffusion. In addition, porous bodies such as a metal-based mesh (grid) metal, a sponge (foamed) metal, or a perforated metal may be used, wherein the metal may be, for example, copper, nickel, aluminum, stainless steel, or the like.

In the lithium-air secondary battery of the present invention, the separator can be used without limitation as long as it can perform a function of electrically separating the positive electrode and the negative electrode, for example, polyethylene (PE), polypropylene (PP) Or a porous insulating material such as a non-woven fabric such as a porous sheet or nonwoven fabric composed of a resin such as polyester, cellulose or polyamide, or the like can be used.

The shape of the lithium-air secondary battery of the present invention is not particularly limited as long as it can accommodate the positive electrode, the negative electrode, the separator and the electrolyte composition described above, and may be, for example, cylindrical, coin type, flat plate type, or laminate type.

The case containing the lithium-air secondary battery of the present invention may be an air-open battery case or a sealed battery case. The open air battery case has a vent through which the atmosphere can enter and exit, whereby the atmosphere can contact the cathode (anode). On the other hand, it is preferable to provide a gas (air) supply pipe and a discharge pipe in the sealed battery case. In this case, the gas to be supplied and discharged is preferably a dry gas, and among these, a high oxygen concentration is preferable, and more preferably pure oxygen (99.99%). In addition, it is preferable to increase the oxygen concentration during discharge and to lower the oxygen concentration during charge.

Although the electrolyte composition and the secondary battery of the present invention are suitable for use as a secondary battery, their use as a primary battery is not excluded.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited to these.

[ Example ]

<Production of Lithium-Air Secondary Battery>

Carbon black (Vulcan XC-72): Polyvinylidene difluoride (PVDF) was mixed at a weight ratio of 90:10, respectively, and the mixture was dispersed in a solvent, N-methyl-2-pyrrolidone, to form a cathode active material layer. A positive electrode was prepared by coating the positive electrode active material layer composition on a positive electrode current collector made of carbon paper (TGP-H-030, manufactured by Toray).

Meanwhile, graphite (LiC ₆ ), styrene-butadiene rubber (SBR) and carboxy methyl cellulose (CMC) were mixed in a weight ratio of 90: 5: 5, and 1.5 parts by weight of distilled water was added based on a total of 100 parts by weight of the mixture. Then, the mixture was stirred for 30 minutes using a mechanical stirrer to prepare a negative electrode active material slurry, and then coated on a copper (Cu) current collector to a thickness of about 200 μm and dried, and dried again under vacuum and 110 ° C. to dry the negative electrode. Prepared.

The prepared positive and negative electrodes were placed in a battery case, and a porous filter (Whatman) was inserted as a separator therebetween, and a lithium-air secondary battery was injected by injecting an electrolyte composition having the composition shown in Table 1 below. Prepared.

In the production of the cathode, an oxygen (O ₂ ) movement path was formed in the cathode active material layer so that oxygen (O ₂ ) was introduced.

<Discharge capacity measurement>

The discharge experiment of the lithium-air secondary battery was conducted using a potentiostat (Potentiostat, bio-Logic, VMP3). Specifically, a current density of 100 mA / g was added to the carbon black weight in the anodes of Examples 1 to 9 or Comparative Examples 1 to 4 to discharge by a voltage cut-off method, and the lower limit voltage was set to 2.0 V. Discharge experiments of lithium-air secondary batteries prepared in Examples 1 to 9 and Comparative Examples 1 to 4 were carried out under conditions filled with 1.5 atm of pure oxygen in an enclosed space, and the charge and discharge were repeated 10 times. After the 10th time, the retention rate compared to the initial discharge capacity was calculated. The measurement results are shown in Table 2 below.

As shown in Table 2, in Examples 1 to 9 according to the present invention, the initial (first time) discharge capacity was excellent as 2,500 mAh / g or more, and after the 10th charge and discharge, the retention rate relative to the initial discharge capacity This was very good at over 98%.

However, in the case of Comparative Examples 1 to 3 where the DMI content of the electrolyte composition was lower than that of the examples, after the 10th charge and discharge, the retention ratio was significantly reduced to less than 70% of the initial discharge capacity. In addition, in Comparative Examples 3 and 4 where the lithium salt molar concentration was lower than that of the examples, the initial (first time) discharge capacity was significantly reduced to less than 2,500 mAh / g.

Claims (11)

Non-aqueous electrolyte solvents containing diether of anhydrosugar alcohols; And
It includes; lithium salt,
The content of the diether of the anhydrosugar alcohol in 100% by weight of the non-aqueous electrolyte solvent exceeds 15% by weight, and the molar concentration of the lithium salt in the composition exceeds 0.4M,
Electrolyte composition. The electrolyte composition of claim 1, wherein the anhydrosugar alcohol is selected from the group consisting of isosorbide, isomannide, isoidide, or mixtures thereof. The electrolyte composition of claim 1, wherein the diether of the anhydrosugar alcohol is a diC ₁ -C ₄ alkyl ether of the anhydrosugar alcohol. The electrolyte composition according to claim 1, wherein the diether of the anhydrosugar alcohol is dimethyl isosorbide. The electrolyte composition according to claim 1, wherein the non-aqueous electrolyte solvent further comprises an organic solvent other than the diether of the anhydrosugar alcohol. The organic solvent of claim 5, wherein the organic solvent other than the diether of the anhydrosugar alcohol is 1,2-dimethoxyethane, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone, sulfolane, or two or more thereof. An electrolyte composition, which is a mixture. The lithium salt of claim 1, wherein the lithium salt is LiSCN, LiBr, LiI, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiCH ₃ SO ₃ , LiCF ₃ SO ₃ , LiClO ₄ , LiBPh ₄ , LiC (CF ₃ SO ₂ ) _At least one electrolyte selected from the group consisting of ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (SFO ₂ ) ₂ , or LiN (CF ₃ CF ₂ SO ₂ ) ₂ ; Composition. The electrolyte composition of claim 1, wherein the molar concentration of the lithium salt is greater than 0.4 M to 2.0 M or less. The electrolyte composition according to claim 1, further comprising an overcharge preventing agent, a dehydrating agent, a deoxidizing agent, a characteristic improving agent for improving capacity retention characteristics and cycle characteristics after high temperature storage, or a combination of two or more thereof. anode; cathode; Separator; And an electrolyte solution, the lithium-air secondary battery comprising:
The lithium-air secondary battery, characterized in that the electrolyte solution comprises the electrolyte composition according to any one of claims 1 to 9. The lithium-air secondary battery according to claim 10, wherein oxygen is used as the positive electrode active material.