JP2011171072A - Nonaqueous electrolyte air battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte air battery capable of reducing an irreversible capacity. <P>SOLUTION: In an F type electrochemical cell 20, a positive electrode 23 and a negative electrode 25 are mutually opposed and set in a casing 21 via a separator 27, and a nonaqueous electrolyte 28 is injected between the positive electrode 23 and the negative electrode 25. In the positive electrode 23, electrolytic manganese dioxide, a radical polymer having a nitroxyl radical or the like is contained as an oxidation-reduction catalyst to oxygen. Further, in the nonaqueous electrolyte 28, a heavy mass number solvent where a stable isotope larger in mass number in a predetermined element is contained is included. The heavy mass number solvent is stable to an oxygen radical considered to be generated in the positive electrode during discharge. Thus, decomposition of the nonaqueous electrolyte by the reaction between the oxygen radical and the nonaqueous electrolyte or the like is further suppressed to more reduce the irreversible capacity. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

Conventionally, as a non-aqueous electrolyte air battery, 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 an ion interposed between the negative electrode and the positive electrode A device provided with a conductor 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 potential of 2.5 to 2.7 V, a charge potential of 4.2 to 4.4 V, and a discharge capacity of about 1000 mAh / g per carbon.

  By the way, when the charge potential is much higher than the discharge potential, the energy is the product of the voltage and the capacity. Therefore, if the capacity is the same in charge and discharge, the charge energy will greatly exceed the discharge energy, Discharge efficiency decreases. In this regard, in Non-Patent Document 1, when the manganese dioxide catalyst is not included in the positive electrode, the charging potential is about 4.5 V, whereas when the positive electrode includes the manganese dioxide catalyst, the charging potential is 4.2 to 4.2. It is about 4.4 V, and it is shown that the charge potential is lowered by the manganese dioxide catalyst and the charge / discharge efficiency is improved.

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

  However, in the lithium-air battery described in Non-Patent Document 1, the charge potential is still high. The irreversible capacity indicating the difference sometimes increased. For this reason, it was desired to further reduce the irreversible capacity.

  The present invention has been made to solve such a problem, and a main object of the present invention is to provide a nonaqueous electrolyte air battery capable of further reducing the irreversible capacity.

  In order to achieve the above-described object, the present inventors have produced an air battery using a non-aqueous solvent deuterated as an electrolyte solvent, and found that the irreversible capacity can be reduced, thereby completing the present invention. Reached

That is, the non-aqueous electrolyte air battery of the present invention is
A positive electrode having an oxygen redox catalyst;
A negative electrode having a negative electrode active material capable of occluding and releasing metal;
A non-aqueous electrolyte solution having a heavy mass solvent that is interposed between the positive electrode and the negative electrode and contains a stable isotope having a larger mass number in a predetermined element;
Is included.

  In this non-aqueous electrolyte air battery, the irreversible capacity can be further reduced. The reason why such an effect is obtained is not clear, but deuterated dimethyl sulfoxide, deuterated acetonitrile, and other deuterated mass solvents are stable against oxygen radicals generated on the positive electrode during discharge. It is considered that the decomposition of the nonaqueous electrolytic solution due to the reaction between the radical and the nonaqueous solvent is further suppressed, and the irreversible capacity can be further reduced.

2 is a cross-sectional view of an F-type electrochemical cell 20. FIG. 2 is a charge / discharge curve of Example 1. FIG. 3 is a charge / discharge curve of Comparative Example 1. 2 is a charge / discharge curve of Example 2. FIG. It is a charging / discharging curve of the comparative example 2. 4 is a charge / discharge curve of Example 3. 10 is a charge / discharge curve of Comparative Example 3. It is a charging / discharging curve of Example 4. It is a charging / discharging curve of the comparative example 4. 10 is a charge / discharge curve of Example 5. 10 is a charge / discharge curve of Comparative Example 5. 7 is a charge / discharge curve of Example 6.

  The non-aqueous electrolyte air battery of the present invention comprises a positive electrode having an oxygen redox catalyst, a negative electrode having a negative electrode active material, a stable isotope having a larger mass number in a predetermined element, interposed between the positive electrode and the negative electrode. And a non-aqueous electrolyte solution having a heavy mass solvent.

In the nonaqueous electrolyte air battery of the present invention, the positive electrode uses oxygen from a gas as the positive electrode active material. The gas may be air or oxygen gas. This positive electrode contains an oxygen redox catalyst. The oxygen redox catalyst may be a metal oxide such as manganese dioxide or tricobalt tetroxide, or may be a metal such as Pt, Pd or Co, metal porphyrin, metal phthalocyanine, or ionized fullerene. Organic and inorganic compounds such as Among these, electrolytic manganese dioxide is preferable in that it can be easily obtained. The oxygen redox catalyst may be a stable radical compound having a structure containing a stable radical skeleton. Here, a stable radical skeleton refers to a long radical that exists as a radical. For example, the spin density measured by electron spin resonance analysis is 10 ¹⁹ spins / g or more, preferably 10 ²¹ spins / g or more. It is good also as a thing. The stable radical compound is selected from the group consisting of, for example, a skeleton having a nitroxyl radical, a skeleton having an oxy radical, a skeleton having a nitrogen radical, a skeleton having a sulfur radical, a skeleton having a carbon radical, and a skeleton having a boron radical. Those having a radical skeleton are preferred. Specifically, a skeleton having a nitroxyl radical as shown in formulas (1) to (9), a skeleton having a phenoxy radical (oxy radical) as shown in formula (10), and formulas (11) to (13) And those containing a skeleton having a hydrazyl radical (nitrogen radical) as shown in the above, and a skeleton having a carbon radical as shown in formulas (14) and (15). Of these, those containing a skeleton having a nitroxyl radical are particularly preferred, and those having a skeleton as represented by formulas (1), (2) and (4) are more preferred. The stable radical compound may be a single skeleton as described above, or may be a compound having a structure in which a polycyclic aromatic ring is linked to a stable radical skeleton, or a polymer is linked to a stable radical skeleton. A compound having the above structure may be used. In the former case, the reduction catalyst function can be sufficiently exerted because it is easily dispersed and present in the positive electrode. In the latter case, the reduction catalyst function is exhibited over a long period of time because it does not easily flow out of the positive electrode. Can do. Examples of the polycyclic aromatic ring include naphthalene, phenalene, triphenylene, anthracene, perylene, phenanthrene, and pyrene. Examples of the polymer include polyethylene and polypropylene. The polymer or polycyclic aromatic ring may be directly connected to the radical skeleton, or may be selected from the group consisting of ester bond, amide bond, urea bond, urethane bond, carbamide bond, ether bond and sulfide bond. A spacer may be connected to the radical skeleton via the spacer. Compound A is an example of a compound having a structure in which a polycyclic aromatic ring (pyrene) is linked to a stable radical skeleton via a spacer (amide bond), and Compound X is a polymer (polypropylene) having a spacer (ester bond). It is an example of a compound having a structure linked to a stable radical skeleton via The polymer preferably has a number average molecular weight of 5,000 to 500,000 and a weight average molecular weight of 10,000 to 1,000,000. The oxidation-reduction catalyst is preferably 2% by weight or more and 60% by weight or less, more preferably 50% by weight or more and 60% by weight or less per positive electrode mixture. If it is 2% by weight or more, it is too little to oxidize and reduce oxygen, and if it is 60% by weight or less, the electrical conductivity and strength can be secured without reducing too much conductive material and binder described later. is there.

The positive electrode of the lithium secondary battery of the present invention is, for example, a mixture of a positive electrode active material capable of occluding and releasing lithium, a conductive material, and a binder, and adding a suitable solvent to form a paste-like positive electrode material. It may be formed by applying and drying on the surface of the electric body and, if necessary, compressing to increase the electrode density. The conductive material is not particularly limited as long as it is an electron conductive material that does not adversely affect the battery performance of the positive electrode. For example, graphite such as natural graphite (scale-like graphite, scale-like graphite) or artificial graphite, acetylene black, carbon black, What mixed 1 type (s) or 2 or more types, such as ketjen black, carbon whisker, needle coke, carbon fiber, metal (copper, nickel, aluminum, silver, gold, etc.) can be used. Among these, as the conductive material, carbon black and acetylene black are preferable from the viewpoints of electron conductivity and coatability. The binder plays a role of connecting the active material particles and the conductive material particles. For example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), fluorine-containing resin such as fluorine rubber, or polypropylene, Thermoplastic resins such as polyethylene and polyacrylonitrile, ethylene-propylene-dienemer (EPDM), sulfonated EPDM, natural butyl rubber (NBR) and 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) that is an aqueous binder may be used. The amount of the binder is preferably 3 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the conductive material carrying the catalyst. If it is 3 parts by weight or more, it is sufficient to maintain the strength of the positive electrode, and if it is 15 parts by weight or less, the amount of the oxidation-reduction catalyst and the conductive material does not decrease too much and the progress of the battery reaction is not hindered. Because it is. Examples of the solvent for dispersing the positive electrode active material, the conductive material, and the binder include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, and N, N-dimethylaminopropyl. Organic solvents such as amine, ethylene oxide, and tetrahydrofuran can be used. Moreover, a dispersing agent, a thickener, etc. may be added to water, and an active material may be slurried with latex, such as SBR. As the thickener, for example, polysaccharides such as carboxymethyl cellulose and methyl cellulose can be used alone or as a mixture of two or more. Examples of the application method include roller coating such as applicator roll, screen coating, doctor blade method, spin coating, bar coater, and the like, and any of these can be used to obtain an arbitrary thickness and shape. The current collector is preferably a porous body such as a net or mesh to allow oxygen to diffuse quickly, and may be a porous metal plate such as stainless steel, nickel, or aluminum. The current collector may have a surface coated with an oxidation-resistant metal or alloy film in order to suppress oxidation. In addition, a transparent conductive material such as InSnO ₂ , SnO ₂ , ZnO, In ₂ O _3, fluorine-doped tin oxide (SnO ₂ : F), antimony-doped tin oxide (SnO ₂ : Sb), tin-doped indium oxide (In ₂ O ₃ : Sn), aluminum-doped zinc oxide (ZnO: Al), gallium-doped zinc oxide (ZnO: Ga) and other materials doped with a single layer or laminate on glass or polymer Good. The film thickness is not particularly limited, but is preferably 3 nm or more and 10 μm or less. The glass or polymer surface may be flat or may have irregularities on the surface.

  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 occlude and release metals, and can be used for air batteries, but can occlude and release at least one of alkali metals and alkaline earth metals. Among these, it is more preferable that at least one of lithium, magnesium, and calcium can be occluded and released. Examples of the negative electrode capable of occluding and releasing lithium include metal lithium and lithium alloys, metal oxides, metal sulfides, and carbonaceous materials that occlude and release lithium. Examples of the lithium alloy include alloys of lithium with aluminum, tin, magnesium, indium, calcium, silicon, and the like. Examples of the metal oxide include tin oxide, silicon oxide, lithium titanium oxide, niobium oxide, and tungsten oxide. Examples of the metal sulfide include tin sulfide and titanium sulfide. Examples of the carbonaceous material that occludes and releases lithium include graphite, coke, mesophase pitch-based carbon fiber, spherical carbon, and resin-fired carbon. In addition, iron phosphide may be used. If it has such a negative electrode active material, it can be set as a lithium air battery. Examples of the negative electrode active material capable of occluding and releasing magnesium include the metal oxides, metal sulfides, and carbonaceous materials described above in addition to magnesium metal and magnesium alloys. Examples of the magnesium alloy include an alloy of aluminum and magnesium. If it has such a negative electrode active material, it can be set as a magnesium air battery. Examples of the negative electrode active material capable of occluding and releasing calcium include the above-described metal oxides, metal sulfides, and carbonaceous materials in addition to calcium metal and calcium alloys. If such a negative electrode active material is used, it can be set as a calcium air battery. As the conductive material, binder, solvent and the like used for the negative electrode, those exemplified for the positive electrode can 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. The shape of the current collector can be the same as that of the positive electrode. 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, as the nonaqueous electrolyte solution interposed between the positive electrode and the negative electrode, for example, a nonaqueous electrolyte solution in which a supporting salt is dissolved in a nonaqueous solvent can be used. This non-aqueous electrolyte has a heavy mass number solvent. Here, the heavy mass solvent includes a stable isotope having a larger mass number in a given element, that is, a stable isotope having a larger mass number than the stable isotope existing most frequently in nature in the given element. It shall mean the solvent it contains. Here, the predetermined element means all or a part of elements constituting the nonaqueous solvent molecule, and may be one kind or plural kinds. Moreover, when there are a plurality of the same kind of elements constituting the nonaqueous solvent molecule, all or a part of them may be used. The heavy mass solvent is not particularly limited, but should be a heavy mass solvent such as sulfoxides such as dimethyl sulfoxide, nitriles such as acetonitrile and propyl nitrile, and furans such as tetrahydrofuran and 2-methyltetrahydrofuran. Can do. At this time, N, N-diethyl-N-ethyl-N- (2-methoxyethyl) ammonium bis (trifluorosulfonyl) imide, N-methyl-N-propylpiperidium bis (trifluorosulfonyl) imide, 1-methyl A mixed solvent including an ionic liquid such as -3-propylimidazolium bis (trifluorosulfonyl) imide, 1-ethyl-3-butylimidazolium tetrafluoroborate, and the above-described heavy mass solvent may be used. The ionic liquid itself described above may be a heavy mass solvent. Examples of the predetermined element in the heavy mass solvent include hydrogen, carbon, nitrogen, and oxygen. That is, as the heavy mass solvent, a deuterated solvent in which hydrogen ¹ H in the solvent is deuterium ² H, ¹² C in the solvent is ¹³ C, ¹⁴ N in the solvent is ¹⁵ N And those in which ¹⁶ O in the solvent is changed to ¹⁸ O. Of these, the heavy mass solvent is preferably a deuterated solvent. A heavy mass solvent is considered to be stable against oxygen radicals generated at the positive electrode during discharge, but a deuterated solvent is more stable against oxygen radicals, oxygen radicals and non-water This is because it is considered that decomposition of the non-aqueous electrolyte due to reaction with the solvent can be further suppressed. In the deuterated solvent, the proportion of hydrogen to be deuterated is not particularly limited, but it is preferably larger. For example, in the case of having 6 hydrogens per molecule of solvent molecules such as the above-mentioned dimethyl sulfoxide ((CH ₃ ) ₂ SO), dimethyl sulfoxide-d ₁ in which only one hydrogen is deuterated. However, dimethyl sulfoxide-d ₆ in which all six hydrogens are deuterated is preferred. Further, if the above acetonitrile (CH ₃ CN), it is preferable that all three hydrogen is acetonitrile -d ₃ deuterated. This is because it becomes more stable against oxygen radicals and it is considered that the decomposition of the non-aqueous electrolyte can be further suppressed. Further, when the deuterated solvent has a chain hydrocarbon skeleton, the carbon chain is preferably short, for example, the carbon chain is preferably 1 or more and 5 or less, more preferably 1 or more and 3 or less. . This is because it is considered that the decomposition of the non-aqueous electrolyte can be further suppressed by reducing the number of hydrocarbon chain portions that easily react with oxygen radicals. Here, deuterated dimethyl sulfoxide is particularly preferable as the heavy mass solvent used in the lithium-air battery. Moreover, as a heavy mass number solvent used for a magnesium air battery or a calcium air battery, it is preferable that they are deuterated dimethyl sulfoxide or deuterated acetonitrile. These electrolytic solutions may be used as a gel electrolytic solution. For example, the electrolyte contains a polymer such as polyvinylidene fluoride, polyethylene glycol, and polyacrylonitrile, or a saccharide such as an amino acid derivative or a sorbitol derivative, which contains a supporting salt. It can be used as a gel electrolyte.

The supporting salt is not particularly limited, and a known supporting salt can be used. For example, in the case of a lithium-air battery, LiPF ₆ , LiClO ₄ , LiAsF ₆ , LiBF ₄ , Li (CF ₃ SO ₂ ) ₂ N, Li (CF ₃ SO ₃ ), LiN (C ₂ F ₅ SO ₂ ) _2, etc. Can be used. These supporting salts may be used alone or in combination. In the case of a lithium air battery, the concentration of the supporting salt is preferably 0.1 to 2.0M, and more preferably 0.8 to 1.2M. In the case of an alkaline earth metal air battery such as a magnesium air battery or a calcium air battery, when the alkaline earth metal element is M, perchlorate salt (M (ClO ₄ ) ₂ ), bis (trifluoromethyl) Sulfonyl) imide salt (M [N (CF ₃ SO ₂ ) ₂ ]), trifluoromethanesulfonate salt (M (CF ₃ SO ₃ ) ₂ ), fluorobutanesulfonate salt (M (C ₄ F ₉ SO ₃ ) ₂ ), A salt containing a known group 2 element such as an organic aluminate can be used. Specifically, in the case of a magnesium air battery, examples of the supporting salt include magnesium perchlorate, magnesium bis (trifluoromethylsulfonyl) imide, magnesium trifluoromethanesulfonate, magnesium fluorobutanesulfonate, and organic magnesium aluminate. In the case of a calcium air battery, examples of the supporting salt include calcium perchlorate, calcium bis (trifluoromethylsulfonyl) imide, calcium trifluoromethanesulfonate, calcium fluorobutanesulfonate, and calcium organic aluminate. In the case of an alkaline earth metal air battery, the concentration of the supporting salt is preferably 0.1 to 1.5M, and more preferably 0.3 to 0.6M.

  The nonaqueous electrolyte air battery of the present invention may include a separator between the lithium negative electrode and the positive electrode. The separator is not particularly limited as long as it is a composition that can withstand the use of a nonaqueous electrolyte air battery. A porous 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 used for an electric vehicle etc.

  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.

  Below, the example which produced the lithium secondary battery concretely is demonstrated as an Example.

[Example 1]
The positive electrode was produced as follows. 10 parts by weight of electrolytic manganese dioxide as a catalyst, 85 parts by weight of Ketjen black (ECP-600JD manufactured by Mitsubishi Chemical) as a conductive auxiliary agent, and 5 parts by weight of Teflon powder (manufactured by Daikin Industries) (Teflon is a registered trademark) as a binder After mixing and kneading in a ratio using a mortar, 5 mg of the positive electrode mixture formed into a thin film was pressure-bonded to a stainless steel mesh (SUS304 made by Niraco), vacuum-dried, and non-aqueous electrolyte air secondary A positive electrode of the battery was obtained. 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.

  FIG. 1 is a cross-sectional view of an F-type electrochemical cell 20 (made by Hokuto Denko) used in the charge / discharge test. The F-type electrochemical cell 20 was assembled as follows in a glove box under an argon atmosphere. First, the negative electrode 25 was installed in the casing 21 made of SUS, and the positive electrode 23 and the negative electrode 25 were set to face each other through a separator 27 (E25MMS manufactured by Tonen Tapils). Next, 5 mL of an electrolytic solution in which 1 mol / L lithium bistrifluoromethanesulfonylimide was dissolved in deuterated dimethyl sulfoxide (DMSO-D form) (manufactured by Tokyo Chemical Industry) was injected between the positive electrode 23 and the negative electrode 25. Thereafter, the foamed nickel plate 22 was placed on the positive electrode 23, and air was pressed from above with a pressing member 29 capable of flowing to the positive electrode 23 side, whereby the cell was fixed and the electrochemical cell of Experimental Example 1 was obtained. The gas reservoir 24 of the F-type electrochemical cell 20 was filled with dry oxygen.

  The F-type electrochemical cell 20 thus obtained was connected to a charge / discharge device (HJ1001SM8A) manufactured by Hokuto Denko, and a current of 20 mA / g per positive electrode mixture was passed between the positive electrode 23 and the negative electrode 25. The battery was discharged to 2.4 V, then charged to 4.0 V with a current of 10 mA / g, and the irreversible capacity was determined. The irreversible capacity is expressed as a percentage between the discharge capacity and the charge capacity. In FIG. 2, the charging / discharging curve of Example 1 is shown. The irreversible capacity was 28.9%.

[Comparative Example 1]
The electricity of Comparative Example 1 was the same as Example 1 except that the electrolytic solution was dimethyl sulfoxide (DMSO-H form) (manufactured by Wako Pure Chemical Industries, dehydrated) instead of deuterated dimethyl sulfoxide. A chemical cell was created and a charge / discharge test was performed. In FIG. 3, the charging / discharging curve of the comparative example 1 is shown. The irreversible capacity of Comparative Example 1 was 39.1%.

[Example 2]
Except that the positive electrode was replaced with electrolytic manganese dioxide (Mitsui Mining & Mining) and the above-mentioned compound X was used, except that this compound X was 166 mg, ketjen black was 116 mg, teflon powder was 24 mg, and the positive electrode mixture was used. In the same manner as in Example 1, an electrochemical cell of Example 2 was prepared and a charge / discharge test was performed. In FIG. 4, the charging / discharging curve of Example 2 is shown. The irreversible capacity of Example 2 was 27.3%.

  As this compound X, Chem. Phys. Lett. Vol. 359, p351 (2002), polymerization of 2,2,6,6-tetramethylpiperidine methacrylate monomer using 2,2′-azobisisobutyronitrile as an initiator, followed by 3-chloroperben What was obtained by oxidizing with zoic acid was used (number average molecular weight 92,000, weight average molecular weight 2299,000).

[Comparative Example 2]
An electrochemical cell of Comparative Example 2 was prepared in the same manner as in Example 2 except that dimethyl sulfoxide was used instead of deuterated dimethyl sulfoxide, and a charge / discharge test was performed. FIG. 5 shows a charge / discharge curve of Comparative Example 2. The irreversible capacity of Comparative Example 2 was 43.1%.

[Example 3]
Except for using Pyrenyl-2,2,6,6-tetramethylpiperidine-1-oxyl represented by Compound A in place of Compound X as the positive electrode and adding the amount of Compound A to 0.056 mmol, The electrochemical cell of Example 3 was created in the same manner as Example 2, and a charge / discharge test was performed. In FIG. 6, the charging / discharging curve of Example 3 is shown. The irreversible capacity of Example 3 was 24.3%.

  Compound A was synthesized as follows. Under an argon atmosphere, 246 mg of 1-hydroxycarbonylpyrene (manufactured by Aldrich) was placed in a 100 mL 2-neck eggplant flask, and 6 mL of N, N-dimethylformamide (DMF) was added and dissolved. Then, 304 mg of 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorphonium chloride (DMT-MM, manufactured by Wako Pure Chemical Industries), 4-amino-2,2 , 6,6-tetramethyl-1-oxypiperidine (manufactured by Tokyo Chemical Industry Co., Ltd.) (188 mg) was dissolved in 15 mL of methanol and added, and the mixture was reacted at room temperature for 24 hours. After completion of the reaction, the solvent was degassed and removed, and the resulting reaction product was dissolved in 50 mL of chloroform. The chloroform solution was extracted with water (twice with 10 mL), 1N aqueous hydrochloric acid (10 mL), and saturated brine (10 mL), and then anhydrous magnesium sulfate was added to the organic layer to perform dehydration, whereby a crude product was obtained. It was. The obtained crude product was purified by silica gel chromatography to obtain 260 mg of an orange solid of compound formula 2.

[Comparative Example 3]
An electrochemical cell of Comparative Example 3 was prepared in the same manner as in Example 3 except that dimethyl sulfoxide was used instead of deuterated dimethyl sulfoxide, and a charge / discharge test was performed. In FIG. 7, the charging / discharging curve of the comparative example 3 is shown. The irreversible capacity of Comparative Example 3 was 38.1%.

[Example 4]
An electrochemical cell of Example 4 was prepared in the same manner as in Example 1 except that the negative electrode was prepared as follows instead of metallic lithium. First, 80 parts by weight of lithium titanate (Ishihara Sangyo), 10 parts by weight of Ketjen Black (Mitsubishi Chemical) and 10 parts by weight of Teflon powder (manufactured by Daikin Industries) were kneaded using a mortar to form a sheet. Metal lithium was used for this, and Li ion was doped, and the negative electrode was created.

  The F-type electrochemical cell 20 thus obtained was connected to a charge / discharge device (HJ1001SM8A) manufactured by Hokuto Denko, and a current of 20 mA / g per positive electrode material was allowed to flow between the positive electrode 23 and the negative electrode 25. The battery was discharged to 0 V and then charged to 2.5 V with a current of 10 mA / g, and the irreversible capacity was determined. In FIG. 8, the charging / discharging curve of Example 4 is shown. The irreversible capacity of Example 4 was 2.3%.

[Comparative Example 4]
An electrochemical cell of Comparative Example 4 was prepared in the same manner as in Example 4 except that dimethyl sulfoxide was used instead of deuterated dimethyl sulfoxide, and a charge / discharge test was performed. In FIG. 9, the charging / discharging curve of the comparative example 4 is shown. The irreversible capacity of Comparative Example 4 was 13.7%.

[Example 5]
The negative electrode was replaced with metallic lithium by a Mg · Al alloy (Al 3% added) having a diameter of 10 mm and a thickness of 0.5 mm, and the electrolyte was dehydrated acetonitrile (acetonitrile-0.5 mol / liter of magnesium perchlorate). An electrochemical cell of Example 5 was prepared in the same manner as in Example 1 except that the D-form was used.

  The F-type electrochemical cell 20 thus obtained was connected to a charge / discharge device (HJ1001SM8A) manufactured by Hokuto Denko, and a current of 2 mA / g per positive electrode material was passed between the positive electrode 23 and the negative electrode 25 to obtain 1. The battery was discharged to 3 mAh and then charged to 3.0 V with a current of 1 mA / g to determine the irreversible capacity. In FIG. 10, the charging / discharging curve of Example 5 is shown. The irreversible capacity was 13.4%.

[Comparative Example 5]
The electrochemical cell of Comparative Example 5 was prepared in the same manner as in Example 5 except that acetonitrile (acetonitrile-H form) was used instead of deuterated acetonitrile, and a charge / discharge test was performed. . In FIG. 11, the charging / discharging curve of the comparative example 5 is shown. The irreversible capacity of Comparative Example 5 was 28.4%.

[Example 6]
An electrochemical cell of Example 6 was prepared in the same manner as in Example 5 except that deuterated dimethyl sulfoxide was used instead of deuterated acetonitrile, and a charge / discharge test was performed. The discharge capacity was 2.1 mAh. In FIG. 12, the charging / discharging curve of Example 6 is shown. The irreversible capacity of Example 6 was 10.2%.

Table 1 summarizes the irreversible capacities of Examples 1 to 5 and Comparative Examples 1 to 6. In the examples described above, dimethyl sulfoxide-d ₆ was used as deuterated dimethyl sulfoxide, and acetonitrile-d ₃ was used as deuterated acetonitrile. Examples 1 to 5 in which the electrolyte solvent was deuterated (D-form) were less irreversible than Comparative Examples 1 to 5 in which the electrolyte solvent was not deuterated (H-form). I found out that From this, it was speculated that the irreversible capacity can be reduced by deuterating the electrolyte solvent regardless of the type of the positive electrode, the negative electrode, the electrolyte solvent or the supporting salt. In Examples 1 to 3 in which the type of the positive electrode was changed, the irreversible capacity of Example 1 was the smallest, and then the irreversible capacity of Example 2 was small. Therefore, as the positive electrode, a compound having a structure containing a stable radical skeleton It was presumed that the irreversible capacity could be reduced without using compound A or compound X. Further, in Examples 5 and 6 in which the type of the electrolyte solvent was changed, Example 6 using deuterated dimethyl sulfoxide had a smaller irreversible capacity than Example 5 using deuterated acetonitrile. As an electrolytic solution solvent, it was found that deuterated dimethyl sulfoxide is more preferable. Moreover, since the irreversible capacity could be reduced even in the magnesium air battery, it was speculated that the irreversible capacity could also be reduced in the calcium air battery using calcium which is the same alkaline earth metal element.

  20 F-type electrochemical cell, 21 casing, 22 nickel foam plate, 23 positive electrode, 24 gas reservoir, 25 negative electrode, 27 separator, 28 electrolyte, 29 holding member.

Claims (5)

A positive electrode having an oxygen redox catalyst;
A negative electrode having a negative electrode active material capable of occluding and releasing metal;
A non-aqueous electrolyte solution having a heavy mass solvent that is interposed between the positive electrode and the negative electrode and contains a stable isotope having a larger mass number in a predetermined element;
Non-aqueous electrolyte air battery containing.   The non-aqueous electrolyte air battery according to claim 1, wherein the heavy mass solvent is a deuterated solvent.   3. The non-aqueous electrolyte air battery according to claim 1, wherein the non-aqueous electrolyte includes one of deuterated dimethyl sulfoxide and deuterated acetonitrile as the deuterium mass solvent.   The non-aqueous electrolyte air battery according to any one of claims 1 to 3, wherein the metal is one or more of lithium, magnesium, and calcium.   The non-aqueous electrolyte air battery according to any one of claims 1 to 4, wherein the positive electrode includes a compound having a structure including a stable radical skeleton as the redox catalyst.

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