JP5831422B2 - Non-aqueous electrolyte for lithium-air batteries - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte used for a lithium-air battery.

  With the spread and progress of devices such as mobile phones in recent years, it is desired to increase the capacity of the battery as the power source. Under such circumstances, the lithium-air battery uses the oxygen in the atmosphere as a positive electrode active material at the air electrode, and the oxygen reduction reaction of the oxygen is performed. On the other hand, the negative electrode oxidizes the metal constituting the negative electrode. Since the reductive reaction can be performed for charging or discharging, it has been attracting attention as a high-capacity battery that has a high energy density and is superior to the currently used lithium ion batteries (Non-patent Document 1).

  Conventionally, an organic solvent has been used as a non-aqueous electrolyte for a lithium-air battery. However, since the organic solvent is volatile and miscible with water, there has been a problem in stability during long-term operation. During long-term battery operation, battery resistance increases due to evaporation of the electrolyte from the positive electrode (air electrode) side, or metal lithium as the negative electrode may be corroded by moisture entering the battery. . These phenomena can be a factor that impairs the characteristics of long-time discharge of the air battery.

  PP13TFSA (N-methyl-) is used as a non-aqueous electrolyte for the purpose of providing a lithium-air battery in which the decrease due to the volatility of the electrolyte and the mixing of moisture into the battery are suppressed and the battery can operate stably for a long time. An air battery using an ionic liquid such as N-propylpiperidinium bis (trifluoromethanesulfonyl) amide) has been proposed (Patent Document 1). An ionic liquid refers to a substance that is composed only of ionic molecules combining a cation and an anion and that is liquid at room temperature (15 ° C. to 25 ° C.).

  In addition, since ionic liquids such as PP13TFSA generally have high viscosity, it is considered that battery resistance increases when used as an electrolyte as it is, making it difficult to operate the battery in a high current density region. On the other hand, it has been proposed to adjust the viscosity of the electrolytic solution by adding an organic solvent having a generally lower viscosity than the ionic liquid to the ionic liquid (Patent Document 2).

JP 2011-14478 A WO2011 / 111185 pamphlet

National Institute of Advanced Industrial Science and Technology (AIST), “Development of high-performance lithium-air battery with new structure”, [online], press release on February 24, 2009, [search on August 19, 2011], Internet <http: // www. aist. go. jp / aist_j / press_release / pr2009 / pr20090224 / pr20090224. html>

  By using an ionic liquid such as PP13TFSA (N-methyl-N-propylpiperidinium bis (trifluoromethanesulfonyl) amide) or a mixed liquid of an ionic liquid and an organic solvent as an electrolytic solution of an air battery, volatilization of the electrolytic solution is performed. Although a certain degree of effect can be obtained in the reduction of the amount of water and suppression of moisture mixing into the battery, and the characteristics of the air battery can be improved to some extent, the discharge capacity as an air battery is still not sufficient. Therefore, an electrolytic solution that can further improve the discharge capacity of the lithium-air battery is desired.

で表されるアンモニウムカチオン（ＤＥＭＥ２）を含み、及びアニオン部として式（２）：

で表されるビス（トリフルオロメタンスルホニル）アミド（ＴＦＳＡ）を含むＤＥＭＥ２ＴＦＳＡであり、
有機溶媒がグライム類であり、
リチウム含有金属塩がリチウムビス（トリフルオロメタンスルホニル）アミド（ＬｉＴＦＳＡ）であり、
ＤＥＭＥ２ＴＦＳＡ及びグライム類の合計に対するＤＥＭＥ２ＴＦＳＡの割合が、モル比で４．５％〜５．５％未満または８０％〜１００％未満である、非水電解液である。 The present invention is a non-aqueous electrolyte for a lithium-air battery comprising an ionic liquid, an organic solvent, and a lithium-containing metal salt,
The ionic liquid has formula (1) as the cation moiety:

And an anion moiety of formula (2):

DEME2TFSA containing bis (trifluoromethanesulfonyl) amide (TFSA) represented by
The organic solvent is glymes,
The lithium-containing metal salt is lithium bis (trifluoromethanesulfonyl) amide (LiTFSA);
It is a nonaqueous electrolytic solution in which the ratio of DEME2TFSA to the total of DEME2TFSA and glymes is 4.5% to less than 5.5% or 80% to less than 100% in a molar ratio.

  ADVANTAGE OF THE INVENTION According to this invention, the electrolyte solution which can obtain the lithium air battery which has a higher discharge capacity than before can be provided.

FIG. 1 is a schematic cross-sectional view of an example of an electrochemical cell including a lithium-air battery configured using the electrolytic solution according to the present invention. FIG. 2 shows the relationship between the ratio of DEME2TFSA to the total of DEME2TFSA and glymes and the discharge capacity at 2.3 V in the cells produced in the examples and comparative examples.

  The non-aqueous electrolyte for a lithium air battery according to the present invention includes an ionic liquid, an organic solvent, and a lithium-containing metal salt. The ionic liquid is DEME2TFSA (N, N-diethyl-N-methyl-N- (2-methoxyethoxyethyl) ammonium bis (trifluoromethanesulfonyl) amide), the organic solvent is glyme, and the lithium-containing metal salt is LiTFSA. (Lithium bis (trifluoromethanesulfonyl) amide). And the ratio of DEME2TFSA with respect to the sum total of DEME2TFSA and glymes is 4.5 to less than 5.5% or less than 80 to 100% in molar ratio.

で表されるアンモニウムカチオン（ＤＥＭＥ２）を含み、アニオン部として式（２）：

で表されるビス（トリフルオロメタンスルホニル）アミド（ＴＦＳＡ）を含む。 DEME2TFSA has formula (1) as the cation moiety:

And an anion moiety represented by formula (2):

And bis (trifluoromethanesulfonyl) amide (TFSA) represented by:

Conventionally, it has been proposed to use an ionic liquid as an electrolytic solution in order to reduce the electrolytic solution by volatilization and prevent moisture from being mixed into the battery, and the ionic liquid has a higher viscosity, so the viscosity is lower than that of the ionic liquid. It has been proposed to add organic solvents to the ionic liquid. However, even if the ionic liquid and the organic solvent are simply mixed, the viscosity decreases due to the melting point drop, but that alone does not allow lithium oxides such as Li ₂ O ₂ and Li ₂ O to be present in the positive electrode during the discharge of the lithium air battery. Precipitation and deposition cause insufficient supply of lithium ions and oxygen, and suppression of volatilization of the electrolyte is insufficient, making it difficult to obtain a desired discharge capacity of the lithium-air battery.

On the other hand, the present inventor has conducted intensive research and found that an ionic liquid excellent in solubility of lithium oxides such as Li ₂ O ₂ and Li ₂ O and having a high oxygen supply ability, compatible with the ionic liquid, and active. The present inventors have found an electrolytic solution in which an organic solvent not containing protons and having a lower viscosity than an ionic liquid is combined with a lithium-containing metal salt.

As a solvent excellent in the solubility of lithium oxides such as Li ₂ O ₂ and Li ₂ O, DEME2TFSA, which is an ionic liquid in which the cation portion contains two ether groups, was found. It has been found that glymes containing ether groups such as tetraglyme and triglyme are preferable as organic solvents that are compatible with ionic liquids and do not contain active protons and have a lower viscosity than ionic liquids. Then, it was found that when DEME2TFSA, glymes, and LiTFSA that is a lithium salt were mixed to prepare an electrolyte, and this was used as an electrolyte of a lithium air battery, a lithium air battery having a high discharge capacity was obtained. .

で表されるＤＥＭＥ３ＴＦＳＡも挙げられる。理論に束縛されるものではないが、イオン液体であるＤＥＭＥ２ＴＦＳＡ及びＤＥＭＥ３ＴＦＳＡは、グライム類等の有機溶媒よりもＬｉ₂Ｏ₂等のリチウム酸化物の溶解性が高いが、ＤＥＭＥ２ＴＦＳＡの方がＤＥＭＥ３ＴＦＳＡに比べてリチウムイオンを受け取りにくいためＬｉ₂Ｏ₂等のリチウム酸化物の溶解性が低下しにくく、リチウム空気電池の電解液に用いたときにリチウムイオンや酸素の拡散経路をより維持しやすいと考えられる。さらに、ＤＥＭＥ２ＴＦＳＡの方がＤＥＭＥ３ＴＦＳＡに比べて酸素供給能が高いことも分かった。 In DEME2TFSA, it is considered that the cation part contains two ether groups, so that the solubility of lithium oxide is excellent. However, as an ionic liquid in which the cation part contains two or more ether groups, in addition to DEME2TFSA, For example, the following formula wherein the cation moiety includes three ether groups:

And DEME3TFSA represented by Although not bound by theory, DEME2TFSA and DEME3TFSA which are ionic liquids have higher solubility of lithium oxides such as Li ₂ O ₂ than organic solvents such as glymes, but DEME2TFSA is more in comparison with DEME3TFSA. Lithium ions are difficult to receive, so the solubility of lithium oxides such as Li ₂ O ₂ is unlikely to decrease, and it is thought that the diffusion path of lithium ions and oxygen is easier to maintain when used in the electrolyte of lithium-air batteries. . Furthermore, it was also found that DEME2TFSA has a higher oxygen supply capacity than DEME3TFSA.

  Grimes are organic solvents that do not contain active protons and have an ether group like DEME2TFSA, but are compatible with DEME2TFSA, have a lower viscosity than DEME2TFSA, and have a high lithium ion transport number. The oxygen supply capacity is low. When such a glyme is mixed with LiTFSA, it coordinates with lithium ions to form a lithium ionic liquid, which makes it difficult for lithium ions to be delivered to DEME2TFSA, which also makes the solubility of lithium oxide of DEME2TFSA And the glymes are less likely to volatilize. For these reasons, it is considered that the electrolyte prepared by mixing DEME2TFSA, glymes, and LiTFSA can improve the discharge capacity of the lithium-air battery.

で表されるテトラグライム、または式（４）：

で表されるトリグライムである。 Grimes are preferably of formula (3):

Or a tetraglyme represented by formula (4):

It is a triglyme represented by

  The grime is more preferably tetraglyme.

  The ratio of DEME2TFSA to the total of DEME2TFSA and glymes is 4.5 to 5.5% or 80 to less than 100% in molar ratio. The range with the smaller proportion of DEME2TFSA is preferably 4.8 to 5.2%, more preferably about 5%. Moreover, the range with the larger ratio of DEME2TFSA is preferably 80 to 99%, more preferably 80 to 95%, and still more preferably 80 to 90%.

  Compared with the case where the electrolyte solution is prepared with 100% DEME2TFSA, a lithium-air battery having a high discharge capacity when the solvent of the electrolyte solution is prepared in a ratio of DEME2TFSA and the above range, which is a mixed solvent of DEME2TFSA and glymes. Can be obtained. In addition, the cost of the electrolytic solution can be reduced. Without being bound by theory, it is possible to obtain a lithium-air battery having a high discharge capacity when DEME2TFSA and glymes are mixed at a predetermined ratio by mixing DEME2TFSA, glymes, and LiTFSA. When the electrolyte solution is prepared, the glymes and LiTFSA are coordinated in the electrolyte solution to form a lithium ionic liquid, and the lithium ionic liquid and DEME2TFSA are uniformly mixed depending on the composition ratio. Or to form a heterogeneously mixed state such as microphase separation.

  The glymes such as tetraglyme and LiTFSA are preferably mixed at a molar ratio of glymes: LiTFSA = 1: 0.8 to 1.1, more preferably at a molar ratio of about 1: 1. Without being bound by theory, when glymes and LiTFSA are mixed in a molar ratio of the above proportions, a large proportion, preferably most, and more preferably all glymes are combined with the lithium ions of LiTFSA. Coordinate to form a large cation group, and think that a large proportion of the electrolyte solution, preferably most, more preferably all components can form lithium ionic liquids of cations and anions. It is done. As a result, it is possible to prepare an electrolyte solution with higher stability and less volatilization while mixing the organic solvent with the ionic liquid to reduce the viscosity of the electrolyte solution, thereby further improving the discharge capacity of the lithium-air battery. It can be improved.

  A lithium air battery can be constructed using the electrolytic solution according to the present invention. The lithium-air battery configured using the electrolyte according to the present invention can include a positive electrode layer, a negative electrode layer, and an electrolyte layer disposed between the positive electrode layer and the negative electrode layer.

  The positive electrode layer can include a conductive material. The conductive material is preferably a porous material, but is not limited thereto. Examples of the porous material include carbon materials such as carbon, and examples of carbon include carbon black such as ketjen black, acetylene black, channel black, furnace black, and mesoporous carbon, activated carbon, and carbon carbon fiber. A carbon material having a large specific surface area is preferably used. Moreover, as a porous material, what has the pore volume of nanometer order of about 1 mL / g is desirable. Preferably, the conductive material accounts for 10 to 99% by mass in the positive electrode layer.

  The positive electrode layer can contain a binder. As the binder, for example, a fluororesin such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluororubber, a thermoplastic resin such as polypropylene, polyethylene, polyacrylonitrile, or styrene butadiene rubber (SBR) is used. be able to. Preferably, the binder accounts for 1 to 40% by mass in the positive electrode layer.

  The positive electrode layer may include a redox catalyst. Examples of the redox catalyst include metal oxides such as manganese dioxide, cobalt oxide, and cerium oxide, noble metals such as Pt, Pd, Au, and Ag, transition metals such as Co, and cobalt phthalocyanine. And organic materials such as metal phthalocyanine and Fe porphyrin. Preferably, the oxidation-reduction catalyst accounts for 1 to 90% by mass in the positive electrode layer.

  In the lithium air battery configured using the electrolytic solution according to the present invention, a separator may be provided between the positive electrode layer and the negative electrode layer. Although it does not specifically limit as a separator, For example, polymer nonwoven fabrics, such as a nonwoven fabric made from a polypropylene, a nonwoven fabric made from a polyphenylene sulfide, microporous films, such as olefin resin, such as polyethylene and a polypropylene, or these combinations can be used. An electrolyte layer may be formed by impregnating a separator with an electrolyte such as a liquid electrolyte.

  The negative electrode layer included in the lithium-air battery configured using the electrolytic solution according to the present invention is a layer containing a negative electrode active material containing lithium. As the negative electrode active material containing lithium, a carbonaceous material of lithium, an alloy containing lithium, or a metal oxide, metal nitride, or metal sulfide containing lithium can be used. Examples of the alloy containing lithium include a lithium aluminum alloy, a lithium tin alloy, a lithium lead alloy, and a lithium silicon alloy. Examples of the metal oxide containing lithium include lithium titanium oxide. Examples of the metal nitride containing lithium element include lithium cobalt nitride, lithium iron nitride, and lithium manganese nitride. Examples of the metal sulfide containing lithium element include lithium sulfide.

  The negative electrode layer may further contain a conductive material and / or a binder. For example, when the negative electrode active material is in the form of a foil, it can be a negative electrode layer containing only the negative electrode active material, and when the negative electrode active material is in a powder form, the negative electrode layer has a negative electrode active material and a binder. be able to. In addition, about a conductive material and a binder, the thing similar to the material which can be used for the above-mentioned positive electrode layer can be used.

  As an exterior material that can be used for a lithium-air battery configured using the electrolytic solution according to the present invention, a material that is usually used as an exterior material for an air battery, such as a metal can, a resin, or a laminate pack, can be used.

  The exterior material can be provided with a hole for supplying oxygen at an arbitrary position, for example, toward the contact surface of the positive electrode layer with air. As the oxygen source, dry air or pure oxygen is preferable.

  The lithium air battery configured using the electrolytic solution according to the present invention can include an oxygen permeable membrane. The oxygen permeable membrane can be disposed, for example, on the positive electrode layer and on the contact portion side with the air opposite to the electrolyte layer. As the oxygen permeable membrane, a water-repellent porous membrane that can transmit oxygen in the air and prevent moisture from entering can be used. For example, a porous membrane made of polyester or polyphenylene sulfide can be used. it can. A water repellent film may be provided separately.

  A positive electrode current collector can be disposed adjacent to the positive electrode layer. The positive electrode current collector is usually disposed on the positive electrode layer and on the contact portion side with the air opposite to the electrolyte layer, but may be disposed between the positive electrode layer and the electrolyte layer. The positive electrode current collector is not particularly limited as long as it is a material conventionally used as a current collector, such as a carbon paper, a porous structure such as a metal mesh, a network structure, a fiber, a nonwoven fabric, etc. A metal mesh formed from SUS, nickel, aluminum, iron, titanium, or the like can be used. A metal foil having oxygen supply holes can also be used as the positive electrode current collector.

  A negative electrode current collector can be disposed adjacent to the negative electrode layer. The negative electrode current collector is not particularly limited as long as it is a material conventionally used as a negative electrode current collector, such as a conductive substrate having a porous structure, a non-porous metal foil, etc. For example, copper, SUS, A metal foil formed from nickel or the like can be used.

  The shape of the lithium-air battery configured using the electrolyte solution according to the present invention is not particularly limited as long as it has a shape having an oxygen uptake hole, such as a cylindrical shape, a square shape, a button shape, a coin shape, or a flat shape, A desired shape can be taken.

  Although the lithium air battery comprised using the electrolyte which concerns on this invention can be used as a secondary battery, you may use it as a primary battery.

  The positive electrode layer and the negative electrode layer included in the lithium-air battery configured using the electrolytic solution according to the present invention can be formed by any conventional method. For example, when forming a positive electrode layer containing carbon particles and a binder, an appropriate amount of a solvent such as ethanol is added to and mixed with a predetermined amount of carbon particles and a binder, and the resulting mixture is rolled to a predetermined thickness with a roll press. The positive electrode layer can be formed by drying and cutting. Next, the positive electrode current collector is pressure-bonded and heated and vacuum dried to obtain a positive electrode layer in which the current collector is combined.

  Alternatively, an appropriate amount of solvent is added to and mixed with a predetermined amount of carbon particles and a binder to obtain a slurry, and the slurry is coated on a substrate and dried to obtain a positive electrode layer. The positive electrode layer obtained as desired may be press-molded. As a solvent for obtaining the slurry, acetone, NMP or the like having a boiling point of 200 ° C. or less can be used. Examples of the process for coating the positive electrode layer of the slurry on the substrate include a doctor blade method, a gravure transfer method, and an ink jet method. The base material used is not particularly limited, and a current collector plate used as a current collector, a base material having film-like flexibility, a hard base material, and the like can be used. For example, SUS foil, polyethylene terephthalate ( A substrate such as PET) film or Teflon (registered trademark) can be used. The same applies to the method of forming the negative electrode layer.

(Preparation of solvent)
A solvent used for the electrolytic solution was prepared. DEMETFSA (N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) amide) containing one ether group was obtained from Kanto Chemical Co., Inc. Tetraglyme (G4) was obtained from Kishida Chemical Co., Ltd. For DEME2TFSA and DEME3TFSA, the starting material 1-bromo-2-methoxyethane in the synthesis of DEMETFSA, which is a known substance, is changed to 1-bromo-2- (2-methoxyethoxy) ethane and diethylene glycol-2-bromoethyl methyl ether. They were synthesized by changing each.

(Production of cell)
Example 1
90% by mass of Ketjen Black (ECP-600JD, manufactured by Ketjen Black International), 10% by mass of polytetrafluoroethylene (PTFE) binder (F-104, manufactured by Daikin), and an appropriate amount of ethanol as a solvent A mixture was obtained. The obtained mixture was rolled with a roll press, dried and cut to obtain a positive electrode layer having a diameter of 18 mmφ and a thickness of 130 μm.

  Using a 100 mesh made of SUS304 (manufactured by Niraco) as a current collector, the positive electrode layer and the current collector were pressure bonded, followed by heating under vacuum drying, and the current collector was combined with the positive electrode layer.

  Using DEME2TFSA and tetraglyme (manufactured by Kishida Chemical Co., Ltd.) as a mixed solvent, LiTFSA (manufactured by high-purity chemical), which is a lithium salt, was dissolved. At that time, DEME2TFSA: LiTFSA: tetraglyme was mixed and dissolved in an Ar atmosphere at 25 ° C. for 12 hours so that the molar ratio was 9: 1: 1 to prepare an electrolytic solution.

  As a negative electrode layer, a metal lithium foil (made by Honjo Metal) having a diameter of 22 mmφ and a thickness of 500 μm was prepared, and attached to a negative electrode current collector of a SUS304 plate (manufactured by Niraco) having a diameter of 22 mm and a thickness of 2 cm.

  As shown in FIG. 1, the negative electrode current collector is on the lower side in a sealed container 9 made of SUS with an insulating resin interposed therebetween so that the positive electrode layer and the negative electrode layer are electrically insulated from each other in an Ar atmosphere. In this way, the negative electrode current collector 7 and the negative electrode layer 3 are arranged, and a polypropylene nonwoven fabric having a thickness of 40 μm and a diameter of 28 mmφ is arranged on the negative electrode layer 3 as a separator, and 100 μL of the prepared electrolyte is injected into the separator. The positive electrode layer 1 and the positive electrode current collector 6 are assembled so that the electrolyte solution penetrates into the voids in the positive electrode (air electrode) layer 1, and a gas reservoir 8 is provided. An electrochemical cell 10 for evaluation was prepared.

  Next, the electrochemical cell 10 was placed in a glass desiccator (500 mL specification) with a gas replacement cock, and the atmosphere in the glass desiccator was replaced with an oxygen atmosphere using pure oxygen (Taiyo Nippon Sanso, 99.9%). .

(Example 2)
Example 1 except that DEME2TFSA: LiTFSA: tetraglyme was mixed and dissolved in an Ar atmosphere at 25 ° C. for 12 hours so that the molar ratio was 4: 1: 1, and an electrolyte was prepared. In the same manner as described above, an evaluation cell was prepared and placed in a glass desiccator substituted with an oxygen atmosphere.

(Example 3)
Example 1 except that DEME2TFSA: LiTFSA: tetraglyme was mixed and dissolved in an Ar atmosphere at 25 ° C. for 12 hours so that the molar ratio was 1:19:19 to prepare an electrolytic solution. In the same manner as described above, an evaluation cell was prepared and placed in a glass desiccator substituted with an oxygen atmosphere.

(Comparative Example 1)
Without mixing tetraglyme in the solvent, DEME2TFSA: LiTFSA: tetraglyme was mixed and dissolved in an Ar atmosphere at 25 ° C. for 12 hours so that the molar ratio was 9.2: 1: 0. An evaluation cell was prepared in the same manner as in Example 1 except that the electrolytic solution was prepared, and placed in a glass desiccator substituted with an oxygen atmosphere.

(Comparative Examples 2 to 5)
In Comparative Examples 2 to 5, DEME2TFSA: LiTFSA: tetraglyme is in a molar ratio of 1: 1: 1, 1: 9: 9, 1:14:14, and 1: 32.3: 32.3, respectively. Thus, a cell for evaluation was prepared in the same manner as in Example 1 except that an electrolyte was prepared by mixing and dissolving in an Ar atmosphere at 25 ° C. for 12 hours. Put it in a desiccator.

(Comparative Example 6)
Without mixing DEME2TFSA in the solvent, DEME2TFSA: LiTFSA: tetraglyme was mixed and dissolved in an Ar atmosphere at 25 ° C. for 12 hours so that the molar ratio was 0: 1: 1. An evaluation cell was prepared in the same manner as in Example 1 except that it was prepared, and the cell was placed in a glass desiccator substituted with an oxygen atmosphere.

(Comparative Example 7)
Without mixing tetraglyme and using DEME3TFSA instead of DEME2TFSA as a solvent, the DEME3TFSA: LiTFSA: tetraglyme is 9.2: 1: 0 in molar ratio at 25 ° C. for 12 hours, Ar An evaluation cell was prepared in the same manner as in Example 1 except that an electrolytic solution was prepared by mixing and dissolving in an atmosphere, and the cell was placed in a glass desiccator replaced with an oxygen atmosphere.

(Comparative Examples 8 to 10)
In Comparative Examples 8-10, DEME3TFSA was used instead of DEME2TFSA, and DEME3TFSA: LiTFSA: tetraglyme were in a molar ratio of 9: 1: 1, 1: 1: 1, and 1:19:19, respectively. An evaluation cell was prepared in the same manner as in Example 1, Comparative Example 2, and Example 3, except that the electrolyte solution was prepared by mixing and dissolving in an Ar atmosphere at 25 ° C. for 12 hours. And placed in a glass desiccator substituted with an oxygen atmosphere.

(Comparative Examples 11-12)
In Comparative Examples 11-12, DEMETFSA was used instead of DEME2TFSA, and DEMETFSA: LiTFSA: tetraglyme was 12: 1 at 25 ° C. so that the molar ratio was 9: 1: 1 and 1: 1: 1, respectively. An evaluation cell was prepared in the same manner as in Example 1 and Comparative Example 2 except that an electrolytic solution was prepared by mixing and dissolving in an Ar atmosphere for a period of time, and placed in a glass desiccator substituted with an oxygen atmosphere. .

(Discharge test)
The evaluation cells placed in the glass desiccators prepared in Examples 1 to 3 and Comparative Examples 1 to 6, 7 to 10, and 11 to 12 were allowed to stand for 3 hours in a 60 ° C. constant temperature bath before starting the test. . Next, using a BTS2004HT (manufactured by Nagano) secondary battery charge / discharge measuring device, the positive electrode layer area standard (positive electrode area: 2.5 cm ² ) is 0.1 mA under the conditions of 60 ° C., pure oxygen, and 1 atmosphere. The discharge characteristics of the cell were measured at a discharge current density of / cm ² .

  In Table 1 and FIG. 2, the relationship between the ratio of the ionic liquid and the discharge capacity at 2.3 V of the cells produced in Examples 1 to 3 and Comparative Examples 1 to 6, 7 to 10, and 11 to 12 is shown. Indicates.

  The air batteries of Examples 1 to 3 produced using an electrolyte containing a predetermined proportion of DEME2TFSA and tetraglyme had a higher discharge capacity than the air battery of Comparative Example 1 produced using an electrolyte containing no tetraglyme. showed that. Moreover, compared with the air battery of Comparative Examples 7-12 produced using the electrolyte solution containing DEMETFSA and DEME3TFSA, Examples 1-3 produced using the electrolyte solution containing DEME2TFSA even if the mixing ratio with tetraglyme is the same. The air battery showed a high discharge capacity.

DESCRIPTION OF SYMBOLS 1 Positive electrode layer 2 Electrolyte layer 3 Negative electrode layer 6 Positive electrode collector 7 Negative electrode collector 8 Gas reservoir 9 Sealed container 10 Electrochemical cell

Claims (5)

A non-aqueous electrolyte for a lithium-air battery comprising an ionic liquid, an organic solvent, and a lithium-containing metal salt,
The ionic liquid is represented by the formula (1):

And an anion moiety of formula (2):

DEME2TFSA containing bis (trifluoromethanesulfonyl) amide (TFSA) represented by
The organic solvent is gley beam,
The lithium-containing metal salt is lithium bis (trifluoromethanesulfonyl) amide (LiTFSA);
The DEME2TFSA and proportions of the DEME2TFSA to the total of the gley beam is less than 100% 4.5% or more 5.5% less or 80% or more by molar ratio, a non-aqueous electrolyte solution. The gley-time is of the formula (3):

Or a tetraglyme represented by formula (4):

The non-aqueous electrolyte of Claim 1 which is a triglyme represented by these. The gley beam is tetraglyme, the non-aqueous electrolyte according to claim 2. The gley arm及 beauty the LiTFSA is 1: 0.8 to 1.1 contained in a molar ratio of non-aqueous electrolyte according to any one of claims 1 to 3. A lithium-air battery having a positive electrode layer, a negative electrode layer, and an electrolyte layer disposed between the positive electrode layer and the negative electrode layer,
The lithium air battery in which the said electrolyte layer contains the nonaqueous electrolyte solution as described in any one of Claims 1-4.

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