JP2013149429A - Nonaqueous electrolyte air cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte air cell whose charging voltage can be lowered.SOLUTION: A nonaqueous electrolyte air cell 10 is filled with a nonaqueous electrolyte 17 while interposing a separator 14 between a negative electrode 12 and a positive electrode 13 as an air electrode. A sealing plate 16 covering the positive electrode 13 is composed of a material through which air can flow. The positive electrode 13 uses oxygen as a positive electrode active material, and contains an annular coupling compound where a plurality of sulfur-containing heterocycles are annularly coupled. Examples of the annular coupling compound include sulflower, cycloocta[1,2-c:3,4-c':5,6-c'':7,8-c'''] tetrathiophene, benzene[1,2-c:3,4-c':5,6-c']trithiophene, and the like.

Description

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

Conventionally, non-aqueous electrolyte air batteries include a negative electrode capable of occluding and releasing lithium ions, a positive electrode including oxygen in the air as a positive electrode active material, and an oxygen redox catalyst, and ion conduction interposed between the negative electrode and the positive electrode. What is provided with a medium is known. Specifically, for example, metallic lithium is used as the negative electrode, a mixture of lithium peroxide, porous carbon, manganese dioxide catalyst, and fluorine resin is used as the positive electrode, and propylene carbonate in which LiPF ₆ is dissolved is used as the non-aqueous electrolyte. Known lithium-air batteries are known (see Non-Patent Document 1). This lithium-air battery has a discharge voltage of 2.5 to 2.7 V and a charge voltage of about 4.2 to 4.4 V.

  By the way, since the energy of the battery is represented by the product of the voltage and the capacity, if the charging voltage is much higher than the discharging voltage, the charging energy is discharged if the charging capacity and the discharging capacity are almost the same. Energy will be greatly exceeded, and charge / discharge efficiency will fall. In this regard, in Non-Patent Document 1, when the manganese dioxide catalyst is not included in the positive electrode, the charging voltage is about 4.5 V, whereas when the positive electrode includes the manganese dioxide catalyst, the charging voltage is 4.2 to 4.2. It is about 4.4 V, and it is shown that the charging voltage is lowered by the manganese dioxide catalyst.

Journal of American Chemical Society (J. Am. Chem. Soc.), 128, 1390-1393, 2006

  However, the lithium-air battery described in Non-Patent Document 1 still has a high charging voltage. For this reason, a non-aqueous electrolyte air battery capable of reducing the charging voltage has been desired.

  The present invention has been made to solve such a problem, and a main object of the present invention is to provide a non-aqueous electrolyte air battery capable of reducing the charging voltage.

  In order to achieve the above-mentioned object, the present inventors added a predetermined cyclic compound containing sulfur, such as monkey, to the positive electrode to produce a non-aqueous electrolyte air battery. The present invention has been completed.

That is, the nonaqueous electrolyte air battery of the present invention is
A positive electrode containing a cyclic linking compound in which oxygen is used as a positive electrode active material and a plurality of sulfur-containing heterocycles are cyclically linked;
A negative electrode having a negative electrode active material;
A non-aqueous ion conductive medium that is interposed between the positive electrode and the negative electrode and conducts metal ions;
It is equipped with.

  In this nonaqueous electrolyte air battery, the charging voltage can be lowered. The reason why such an effect is obtained is not clear, but it is considered that a cyclic linking compound in which sulfur-containing heterocycles are linked in a cyclic manner increases the conductivity of metal ions.

It is explanatory drawing which shows typically an example of the nonaqueous electrolyte air battery 10 of this invention. 2 is an explanatory diagram showing an outline of a configuration of an F-type electrochemical cell 20. FIG. 2 is a charging curve of Example 1 and Comparative Example 1. FIG. 3 is a charging curve of Examples 2 and 3 and Comparative Example 2. It is a charge curve of Examples 4 and 5. It is a charge curve of comparative examples 3 and 4. 6 is a charging curve of Example 6 and Comparative Example 5.

  The nonaqueous electrolyte air battery of the present invention includes a positive electrode, a negative electrode, and an ion conductive medium interposed between the positive electrode and the negative electrode.

  In the nonaqueous electrolyte air battery of the present invention, the positive electrode as the air electrode uses oxygen from a gas as the positive electrode active material. The gas may be air or oxygen gas. This positive electrode includes a cyclic linking compound in which a plurality of sulfur-containing heterocycles are linked in a cyclic manner. The sulfur-containing heterocycle may be a heterocycle containing sulfur, but is preferably a heterocycle containing carbon (C) in addition to sulfur. The sulfur-containing heterocyclic ring may be a three-membered ring, a four-membered ring, a five-membered ring, or a ring having more than that. Further, the sulfur-containing heterocycle may be a saturated heterocycle or an unsaturated heterocycle. Examples of such sulfur-containing heterocycles include, for example, saturated heterocycles such as ethylene sulfide, trimethylene sulfide, tetrahydrothiophene, tetrahydrothiopyran, hexamethylene sulfide, and unsaturated heterocycles such as acetylene sulfide, thiophene, and tiotropylidene. Etc. Moreover, the sulfur-containing heterocycle may have a substituent.

  The connection mode of the cyclic linking compound is not particularly limited as long as the sulfur-containing heterocycle is cyclically connected. For example, the sulfur-containing heterocycles adjacent to each other may be connected so as to share a side with each other, or may be connected by condensing a plurality of sulfur-containing heterocycles to the basic carbon ring. Examples of the former include monkey flour (see formula (1)). The latter includes cycloocta [1,2-c: 3,4-c ′: 5,6-c ″: 7,8-c ′ ″] tetrathiophene (also referred to as tetramer, see formula (2)). ), Benzene [1,2-c: 3,4-c ′: 5,6-c ′] trithiophene (also referred to as trimer, see formula (3)), and the like. The cyclic linking compound preferably contains sulfur having an unshared electron pair. In this way, it is considered that charging can be performed at a lower voltage. Moreover, it is preferable that a cyclic coupling compound is hardly soluble with respect to an ion conductive medium, and it is more preferable that it is insoluble. If it carries out like this, it will be easy to exchange an electron in oxygen at the time of charging / discharging. Further, the cyclic linking compound may have a substituent in a portion other than the above-described sulfur-containing heterocyclic ring.

  The positive electrode is, for example, formed on the surface of the current collector by mixing the above-described cyclic linking compound, conductive material, and binder to form a positive electrode mixture, and compressed to increase the electrode density as necessary. May be. As a method for mixing the positive electrode mixture, an appropriate solvent may be added and wet mixed with the conductive material and the binder. Moreover, you may dry-mix using a mortar etc. As the solvent, for example, a known solvent such as N-methylpyrrolidone can be used. The mixing amount of the cyclic linking compound is not particularly limited, but is preferably 5% by mass or more and 80% by mass or less, and more preferably 10% by mass or more and 50% by mass or less with respect to the whole positive electrode composite material. If the mixed amount of the cyclic linking compound is 5% by mass or more, it is sufficient to obtain the effect of reducing the discharge voltage, and if it is 80% by mass or less, the amount of the conductive material and the binder becomes relatively small. Therefore, conductivity and mechanical strength can be ensured. Moreover, a binder should just be 3 mass% or more and 25 mass% or less with respect to the whole positive electrode compound material, for example, and 15 mass% or more and 20 mass% or less are preferable. The conductive material is not particularly limited as long as it is an electron conductive material that does not adversely affect the performance of the battery. For example, graphite such as natural graphite (scale-like graphite, scale-like graphite) or artificial graphite, acetylene black, carbon black, kettle, etc. A mixture of one or more of chain black, carbon whisker, needle coke, carbon fiber, activated carbon, metal (copper, nickel, aluminum, silver, gold, etc.) can be used. Among these, the conductive material is preferably a carbon material, and carbon black, acetylene black, and ketjen black are preferable from the viewpoints of electron conductivity and coatability. The binder plays a role of holding the positive electrode mixture. For example, a fluororesin such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), fluororubber, or heat such as polypropylene or polyethylene. A plastic resin, ethylene-propylene-dienemer (EPDM), sulfonated EPDM, natural butyl rubber (NBR) or the like can be used alone or as a mixture of two or more. In addition, an aqueous dispersion of cellulose or styrene butadiene rubber (SBR), which is an aqueous binder, can also be used. Current collectors include aluminum, titanium, stainless steel, nickel, iron, calcined carbon, conductive polymer, conductive glass, and aluminum, copper, etc. for the purpose of improving adhesion, conductivity, and oxidation resistance. A surface treated with carbon, nickel, titanium, silver or the like can be used. For these, the surface can be oxidized. Examples of the shape of the current collector include foil, film, sheet, net, punched or expanded, lath, porous, foam, and formed fiber group. The thickness of the current collector is, for example, 1 to 500 μm.

  In the nonaqueous electrolyte air battery of the present invention, the negative electrode has a negative electrode active material. The negative electrode active material is not particularly limited as long as it can absorb and release an alkali metal such as lithium or an alkaline earth metal such as magnesium, and can be used for a nonaqueous electrolyte air battery. Hereinafter, the negative electrode capable of inserting and extracting lithium will be described. Examples of such negative electrodes include metallic lithium and lithium alloys, carbonaceous materials that absorb and release lithium ions, and metal oxides. Examples of the lithium alloy include alloys of lithium with aluminum, tin, magnesium, indium, calcium, silicon, and the like. Examples of the carbonaceous material that absorbs and releases lithium ions include graphite, coke, mesophase pitch-based carbon fiber, spherical carbon, and resin-fired carbon. Examples of the metal oxide include tin oxide, silicon oxide, lithium titanium oxide, niobium oxide, and tungsten oxide. In addition, iron phosphide or the like may be used. The negative electrode current collector includes copper, nickel, stainless steel, titanium, aluminum, calcined carbon, conductive polymer, conductive glass, Al-Cd alloy, etc., as well as improved adhesion, conductivity and reduction resistance. For the purpose, for example, a copper surface treated with carbon, nickel, titanium, silver or the like can be used. For these, the surface can be oxidized. Examples of the shape of the current collector include foil, film, sheet, net, punched or expanded, lath, porous, foam, and formed fiber group.

In the nonaqueous electrolyte air battery of the present invention, the ion conductive medium may be a nonaqueous electrolytic solution in which a supporting salt is dissolved in a nonaqueous solvent, for example. The supporting salt is composed of metal ions occluded and released by the negative electrode and counter ions thereof. For example, when the metal occluded and released by the negative electrode is lithium, the supporting salts include LiPF ₆ , LiClO ₄ , LiBF ₄ , Li (CF ₃ SO ₂ ) ₂ N, LiN ((C ₂ F ₅ SO ₂ ) ₂ ), Known supporting salts such as Li (CF ₃ SO ₃ ) and Li (C ₄ F ₉ SO ₃ ) can be used. Of these, Li (CF ₃ SO ₂ ) ₂ N is preferable. The supporting salt having lithium may be used alone or in combination. Nonaqueous solvents include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate, chain carbonates such as diethyl carbonate, dimethyl carbonate and ethylmethyl carbonate, cyclic ester carbonates such as gamma butyrolactone and gamma valerolactone, tetrahydrofuran In addition to cyclic ethers such as 1,2-methyltetrahydrofuran, chain ethers such as dimethoxyethane and ethylene glycol dimethyl ether, chloroethylene carbonate, fluoroethylene carbonate, 3-methoxypropionitrile, trimethyl phosphate, triphenyl phosphate, sulfolane A known organic solvent such as dimethyl sulfoxide can be used. Of these, trimethyl phosphate and dimethyl sulfoxide are preferred. This is because the charging voltage can be further reduced. These organic solvents may be used alone or in admixture of two or more. As a density | concentration of a supporting salt, it is preferable that the lithium ion mentioned above will be 0.1-2.0M, and it is more preferable that it will be 0.5-1.2M. Further, a deuterated solvent in which all or a part of hydrogen in these organic solvents is deuterium may be used, and for example, dimethyl sulfoxide-d6 or the like can be used. In addition, an ionic liquid or a gel electrolyte may be used as the ion conductive medium. Examples of ionic liquids include N, N-diethyl-N-ethyl-N- (2-methoxyethyl) ammonium bis (trifluorosulfonyl) imide, N-methyl-N-propylpiperidinium bis (trifluorosulfonyl) imide. Etc. can be used. Further, it may be a mixed solvent containing one or more of the ionic liquid and the above-described organic solvent and deuterated solvent. As the gel electrolyte, a known gel electrolyte can be used. For example, an electrolyte solution containing the above-described supporting salt in a saccharide such as a polymer such as polyvinylidene fluoride, polyethylene glycol, or polyacrylonitrile, an amino acid derivative, or a sorbitol derivative is used. Examples thereof include gel electrolytes.

  The nonaqueous electrolyte air battery of the present invention may include a separator between the positive electrode and the negative electrode. The separator is not particularly limited as long as it can withstand the use of a non-aqueous electrolyte air battery. For example, a polymer nonwoven fabric such as a polypropylene nonwoven fabric or a polyphenylene sulfide nonwoven fabric, or a microporous olefin resin such as polyethylene or polypropylene is used. A film is mentioned. These may be used alone or in combination.

  The shape of the nonaqueous electrolyte air battery of the present invention is not particularly limited, and examples thereof include a coin type, a button type, a sheet type, a laminated type, a cylindrical type, a flat type, and a square type. Moreover, you may apply to the large sized thing etc. which are used for an electric vehicle etc. An example of the nonaqueous electrolyte air battery of the present invention is shown in FIG. FIG. 1 is a cross-sectional view schematically showing the configuration of a nonaqueous electrolyte air battery (coin-type battery) 10. In the coin battery 10, a separator 14 is interposed between a negative electrode 12 made of metallic lithium and a positive electrode 13 as an air electrode, and a non-aqueous electrolyte solution 17 is filled. The positive electrode 13 includes the above-described cyclic linking compound, and the sealing plate 16 covering the positive electrode 13 is made of a material capable of circulating air. In such a coin-type battery 10, during discharge, lithium ions are generated from the lithium metal of the negative electrode 12, and the positive electrode 13 takes in oxygen from the outside air through the sealing plate 16, and discharge products (lithium oxide or lithium peroxidation). Product). At the time of charging, the discharge product is decomposed at the positive electrode 13 to generate lithium ions and oxygen, and at the negative electrode 12, metallic lithium is generated from the lithium ions. Moreover, the coin-type battery 10 is assembled as follows. First, the negative electrode 12 is disposed inside the cup-shaped battery case 11, and the separator 14 is disposed over the negative electrode 12 while injecting the non-aqueous electrolyte solution 17. Subsequently, the positive electrode 13 is disposed on the separator 14 so as to face the negative electrode 12, the gasket 15 formed of an insulating material is disposed along the inner periphery of the battery case 11, and a non-aqueous electrolyte solution is provided as necessary. Inject 17 additional. Finally, a sealing plate 16 through which gas can flow is disposed in the opening of the battery case 11, and the end of the battery case 11 is caulked to obtain the coin-type battery 10.

  In such a nonaqueous electrolyte air battery of the present invention, the charging voltage can be reduced. The reason why such an effect is obtained is not clear, but it is considered that the following action is caused by including a cyclic linking compound in which a plurality of sulfur-containing heterocycles are cyclically linked to the positive electrode. For example, the sulfur atom interacts with a metal oxide such as lithium oxide, so that the metal oxide that cannot contribute to ionic conduction is likely to be decomposed (the decomposition voltage is lowered) and the ionic conductivity is increased. . In addition, for example, due to the interaction between the unshared electron pair of the sulfur atom and the oxygen atom of the metal oxide such as lithium oxide, the electron density in the oxygen atom is biased, and the metal ion such as lithium ion near the positive electrode This is also considered to improve mobility.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

(1) Synthesis of sulfur-containing cyclic compound (A) Tetramer (cycloocta [1,2-c: 3,4-c ′: 5,6-c ″: 7,8-c ′ ″] tetrathiophene ) (See Scheme 1)
Under an argon atmosphere, 12.9 mL of 3,4-dibromothiophene (manufactured by Wako Pure Chemical Industries) was added to a three-necked flask, 11.8 mL of tetrahydrofuran (THF, manufactured by Wako Pure Chemical Industries) was added, and then an isopropyl magnesium bromide lithium chloride complex. Of THF (manufactured by SIGMA ALDRICH) was added dropwise at 0 ° C. After stirring for 1 hour, the mixture was stirred at room temperature for 30 minutes. This was cooled again to 0 ° C., and then dropped into a suspension of 23.7 g of CuCl ₂ (manufactured by Wako Pure Chemical Industries) suspended in 10 mL of THF. Then, it heated up gradually to room temperature and stirred overnight. After adding 5N HCl aqueous solution, the organic layer was separated, and the aqueous layer was extracted using diethyl ether (manufactured by Wako Pure Chemical Industries). The organic layers were combined and washed with saturated brine, dried over anhydrous sodium sulfate (manufactured by Wako Pure Chemical Industries), filtered, and then the solvent was distilled off under reduced pressure. The reaction mixture was purified by silica gel column chromatography (manufactured by Kanto Chemical), and further recrystallized from hexane to obtain 7.72 g of 4,4′-dibromo-3,3′-bithiophene.

Under an argon atmosphere, 3.55-mL 1,5-cyclooctadiene (manufactured by Kanto Chemical) and 4.08 g of 2,2′-bipyridine (manufactured by Kanto Chemical) were placed in a three-necked flask, and N, N-dimethylformamide (DMF, Japanese) After adding 40 mL of Kojun Pharmaceutical Co., Ltd., 7.18 g of Ni (COD) ₂ (manufactured by Wako Pure Chemical Industries) was added at room temperature. COD represents 1,5-cyclooctadiene. A solution prepared by dissolving 7.69 g of 4,4′-dibromo-3,3′-bithiophene in 40 mL of THF was added dropwise thereto, followed by heating at 70 ° C. for 24 hours. After adding 5N aqueous HCl, the organic layer was separated and the aqueous layer was extracted with chloroform. The organic layers were combined and washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and then the solvent was distilled off under reduced pressure. The reaction mixture was purified by silica gel column chromatography, and further recrystallized from hexane, whereby 2.25 g of cycloocta [1,2-c: 3,4-c ′: 5,6-c ″: 7 , 8-c ′ ″] tetrathiophene (tetramer) was obtained.

(B) Synthesis of monkey flower (see Scheme 2)
Subsequently, the cycloocta [1,2-c: 3,4-c ′: 5,6-c ″: 7,8-c ′ ″ obtained as described above was placed in a three-necked flask under an argon atmosphere. After adding 1.03 g of tetrathiophene (tetramer) and adding 15 mL of THF, 31.2 mL of a THF / ethylbenzene / heptane solution (manufactured by Tokyo Chemical Industry Co., Ltd.) of lithium diisopropylamide (LDA) was added dropwise at −78 ° C. After stirring for 1 hour, 1.65 g of S ₈ (manufactured by High-Purity Chemical) was added, the temperature was gradually raised to room temperature, and the mixture was stirred overnight. 200 mL of diethyl ether was added, the aqueous layer was separated, and the organic layer was extracted with water. A 5N aqueous HCl solution was added dropwise to the combined aqueous layer. The solid obtained here was filtered, washed with diethyl ether, dried under reduced pressure, and then heated at 480 ° C. under reduced pressure (1.2 Pa) to obtain 75.7 mg of monkey flour.

(C) Synthesis of benzene [1,2-c: 3,4-c ′: 5,6-c ′] trithiophene (trimer) (see Scheme 3)
In an argon atmosphere, put 1.58 mL of 1,5-cyclooctadiene (manufactured by Kanto Chemical) and 2.91 g of 2,2′-bipyridine (manufactured by Kanto Chemical) into a three-necked flask, and add 45 mL of DMF (manufactured by Wako Pure Chemical Industries). After the addition, 5.11 g of Ni (COD) ₂ (manufactured by Wako Pure Chemical Industries) was added at room temperature. To this was added dropwise 1.60 mL of 3,4-dibromothiophene and then heated at 70 ° C. for 24 hours. After adding 5N aqueous HCl, the organic layer was separated and the aqueous layer was extracted with chloroform. The organic layers were combined and washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and then the solvent was distilled off under reduced pressure. The reaction mixture was purified by silica gel column chromatography and further recrystallized from hexane to obtain 153 mg of benzene [1,2-c: 3,4-c ′: 5,6-c ′] trithiophene. It was.

(2) Cell fabrication and charging test
[Example 1]
The positive electrode was produced as follows. 50% by mass of monkey flour as a catalyst, 35% by mass of acetylene black (manufactured by Denki Kagaku Kogyo) as a conductive auxiliary agent, and 15% by mass of Teflon powder (Teflon is a registered trademark, manufactured by Daikin Industries) as a binder are mixed. After kneading using a mortar, it was formed into a thin film. 9.9 mg of this positive electrode mixture was weighed out, pressed onto a stainless steel mesh (manufactured by Niraco, SUS304) and dried to obtain a positive electrode. For the negative electrode, metallic lithium (made by Honjo Metal) having a diameter of 10 mm and a thickness of 0.4 mm was used. As the electrolytic solution, lithium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., Ltd.) was dissolved in dimethyl sulfoxide (manufactured by Wako Pure Chemical Industries, Ltd.) to make 1 mol / L.

  An F-type electrochemical cell 20 was produced using the positive electrode, the negative electrode, and the electrolytic solution described above. FIG. 2 is a cross-sectional view of an F-type electrochemical cell 20 (manufactured by Hokuto Denko). The F-type electrochemical cell 20 was assembled as follows in a glove box under an argon atmosphere. First, the negative electrode 24 was installed in the casing 22 made of SUS, the positive electrode 26 and the negative electrode 24 were set to face each other, and 1.0 mL of the electrolyte solution 28 was injected. Thereafter, a foamed nickel plate 32 was placed on the positive electrode 26, and a gas reservoir 34 through which air can flow to the positive electrode 26 side was disposed thereon, and the cell was fixed to obtain an electrochemical cell of Example 1. The gas reservoir 34 of the F-type electrochemical cell 20 was filled with dry oxygen.

Subsequently, after connecting an F-type electrochemical cell to a charge / discharge device (HJ1001SM8A) manufactured by Hokuto Denko, and discharging for 40 hours at a current density of 0.025 mA / cm ² per surface area of the positive electrode mixture, the surface area of the positive electrode mixture The battery was charged for 40 hours at a current density of 0.025 mA / cm ² . FIG. 3 shows a charging curve of Example 1. In Example 1, the voltage when charged to an electric capacity of 0.6 mAh was 3.29V.

[Comparative Example 1]
An F-type electrochemical cell was prepared and charged in the same manner as in Example 1 except that a positive electrode mixture consisting of only 80% by mass of acetylene black and 20% by mass of Teflon powder was used instead of the positive electrode mixture containing monkey flour. A test was conducted. In FIG. 3, the charge curve of the comparative example 1 is shown. In Comparative Example 1, the voltage when charged to an electric capacity of 0.6 mAh was 3.58V.

[Example 2]
The positive electrode was produced as follows. After mixing 15% by weight monflower as a catalyst, 70% by weight Ketjen black (ECP600JD, manufactured by Mitsubishi Chemical) as a conductive aid, and 15% by weight Teflon powder as a binder, and kneading them using a mortar The film was formed into a thin film. 2.0 mg of this positive electrode mixture was weighed out, pressed onto a stainless steel mesh and dried, and an F-type electrochemical cell was prepared in the same manner as in Example 1 to conduct a charge test. FIG. 4 shows a charging curve of Example 2. In Example 2, the voltage when charged to an electric capacity of 0.6 mAh was 3.42V.

[Example 3]
An F-type electrochemical cell was prepared and charged in the same manner as in Example 2 except that a positive electrode mixture in which 10% by mass of monkey flour, 75% by mass of ketjen black and 15% by mass of Teflon powder were mixed was used. Went. FIG. 4 shows a charging curve of Example 2. In Example 3, the voltage when charged to an electric capacity of 0.6 mAh was 3.50V.

[Comparative Example 2]
An F-type electrochemical cell was prepared in the same manner as in Example 2 except that a positive electrode mixture made of only 80% by mass of ketjen black and 20% by mass of Teflon powder was used instead of the positive electrode mixture containing monkey flour. A charge test was conducted. FIG. 4 shows a charging curve of Comparative Example 2. In Comparative Example 2, the voltage when charged to an electric capacity of 0.6 mAh was 3.57V.

[Example 4]
An F-type electrochemical cell was prepared and subjected to a charge test in the same manner as in Example 1 except that a positive electrode mixture using a tetramer was used instead of monkey flour. FIG. 5 shows a charging curve of Example 4. In Example 4, the voltage when charged to an electric capacity of 0.6 mAh was 3.33V.

[Example 5]
An F-type electrochemical cell was prepared and subjected to a charge test in the same manner as in Example 1 except that a positive electrode mixture using a trimer was used instead of monkey flour. FIG. 5 shows a charging curve of Example 5. In Example 5, the voltage when charged to an electric capacity of 0.6 mAh was 3.35V.

[Comparative Example 3]
An F-type electrochemical cell was prepared and charged in the same manner as in Example 1 except that a positive electrode mixture using poly (3-phenylthiophene-2,5-diyl) (manufactured by SIGMA ALDRICH) instead of monkey flour was used. Went. FIG. 6 shows a charging curve of Comparative Example 3. In Comparative Example 3, the voltage when charged to an electric capacity of 0.6 mAh was 3.62V. Here, poly (3-phenylthiophene-2,5-diyl) is also simply referred to as phenylthiophene.

[Comparative Example 4]
An F-type electrochemical cell was prepared and charged in the same manner as in Example 1 except that a positive electrode mixture using poly (3-dodecylthiophene-2,5-diyl) (manufactured by SIGMA ALDRICH) instead of monkey flour was used. A test was conducted. FIG. 6 shows a charging curve of Comparative Example 4. In Comparative Example 4, the voltage when charged to an electric capacity of 0.6 mAh was 3.75V. Here, poly (3-dodecylthiophene-2,5-diyl) is also simply referred to as dodecylthiophene.

[Example 6]
An F-type electrochemical cell was prepared and charged in the same manner as in Example 1 except that trimethyl phosphate (TMP, manufactured by SIGMA ALDRICH) was used instead of dimethyl sulfoxide. FIG. 7 shows a charging curve of Example 6. In Example 6, the voltage when charged to an electric capacity of 0.2 mAh was 3.37V.

[Comparative Example 5]
An F-type electrochemical cell was prepared in the same manner as in Example 6 except that a positive electrode mixture consisting of only 80% by mass of acetylene black and 20% by mass of Teflon powder was used instead of the positive electrode mixture containing monkey flour. A charge test was conducted. FIG. 7 shows a charging curve of Comparative Example 4. In Comparative Example 5, the voltage when charged to an electric capacity of 0.2 mAh was 3.68V.

(3) Experimental results Table 1 summarizes the material ratios and total amounts of the positive electrode materials of Examples 1 to 6 and Comparative Examples 1 to 5, the type of the electrolyte solvent, and the charging voltage. When Example 1 in which monkey flour was added to the positive electrode was compared with Comparative Example 1 in which monkey flour was not added, Example 1 had a lower charging voltage than Comparative Example 1. In Examples 2 and 3 and Comparative Example 2, ketjen black was used instead of acetylene black, but Examples 2 and 3 in which monkey flour was added to the positive electrode were compared with Comparative Example 2 in which monkey flour was not added. In comparison, the charging voltage was low. From the above, it was found that charging voltage can be reduced by adding monflower to the positive electrode. Further, it has been confirmed that the amount of monflower added is at least 10% by mass or more and 50% by mass or less in the positive electrode mixture, and the charging voltage is reduced. However, it was speculated that the charging voltage could be similarly reduced.

  In Examples 4 and 5 in which tetramer and trimer were added instead of monflower, the charging voltage was lower than that of Comparative Example 1. On the other hand, Comparative Examples 3 and 4 in which phenylthiophene or dodecylthiophene was added instead of monflower had a higher charging voltage than Comparative Example 1. From the above, it was speculated that what is added to the positive electrode is not limited to monkey flour, but it must be a cyclic linking compound.

  Even in Example 6 and Comparative Example 5 using trimethyl phosphate as the electrolyte solvent, comparing Example 6 in which monkey was added to the positive electrode and Comparative Example 5 in which monkey was not added, Example 6 showed a charging voltage. Was low. From the above, it was speculated that the type of electrolyte solvent is not limited to dimethyl sulfoxide, and trimethyl phosphate and others can similarly reduce the charging voltage.

  The present invention is applicable to the battery industry.

  DESCRIPTION OF SYMBOLS 10 Nonaqueous electrolyte air battery, 11 Battery case, 12 Negative electrode, 13 Positive electrode, 14 Separator, 15 Gasket, 16 Sealing plate, 17 Nonaqueous electrolyte, 20 F type electrochemical cell, 22 Casing, 24 Negative electrode, 26 Positive electrode, 28 Electrolyte, 32 foam nickel plate, 34 gas reservoir.

Claims (3)

A positive electrode containing a cyclic linking compound in which oxygen is used as a positive electrode active material and a plurality of sulfur-containing heterocycles are cyclically linked;
A negative electrode having a negative electrode active material;
A non-aqueous ion conductive medium that is interposed between the positive electrode and the negative electrode and conducts metal ions;
A non-aqueous electrolyte air battery.   The non-aqueous electrolyte air battery according to claim 1, wherein the sulfur-containing heterocycle is thiophene. The nonaqueous electrolyte air battery according to claim 1, wherein the compound is a compound according to any one of chemical formulas (1) to (3).