JP2014022210A - Carbon material for metal air secondary battery, positive electrode member for metal air secondary battery including the same, and metal air secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon material for a metal air secondary battery, capable of improving charge/discharge energy efficiency, while attention is focused on a positive electrode of a nonaqueous air battery.SOLUTION: A carbon material for a metal air secondary battery, which contains carbon as a main constituent and has a surface area-based HO amount desorbed when heated at 50°C or above in temperature-rise desorption gas analysis of 3.0×10mol/m, is used.

Description

  The present invention relates to a chargeable / dischargeable metal-air secondary battery.

  In recent years, in the automobile industry, instead of conventional automobiles using engines driven by fuel such as gasoline, hybrid electric cars (HEV) that use an electric motor together with the engine, or electric cars driven only by a motor. (EV) is being developed. The performance of these automobiles using motors (hereinafter, simply referred to as “electric automobiles”) depends greatly on the characteristics of the storage battery that is the source of electrical energy. For this reason, development of storage batteries having excellent characteristics is in progress.

  Lithium ion secondary batteries are lighter and have higher output than other conventional secondary batteries, so they are widely used in storage batteries installed in various other devices including electric vehicles. Has been. At present, the lithium ion secondary battery actually obtained has a weight energy density of about 100 Wh / kg, and its theoretical upper limit is considered to be about 400 Wh / kg. However, for full-scale popularization of electric vehicles, a battery with a larger capacity is required, and it is said that a weight energy density of at least about 500 Wh / kg is required. Therefore, there is a demand for the development of an innovative battery that can be expected to have a greater weight energy density than a lithium ion secondary battery.

  One of the factors that limit the weight energy density of the lithium ion secondary battery is that a lithium-containing transition metal oxide typified by lithium cobaltate is used as the positive electrode material. That is, since the transition metal element that is a constituent element is a heavy metal, when it is incorporated in a storage battery as a positive electrode material, the weight increases, and as a result, the weight energy density decreases. Therefore, in order to avoid such restrictions, metal-air batteries that use oxygen in the atmosphere as the positive electrode material and metal as the negative electrode material have recently attracted attention. When power storage is performed using a metal-air battery as a storage battery, the weight can be reduced as compared with a conventional lithium ion battery, and thus cost reduction can be expected.

  Conventionally, metal-air batteries using zinc have been put into practical use and are used as power supplies for hearing aids. However, conventional metal-air batteries have only been put into practical use as primary batteries, and have not yet been put into practical use as chargeable / dischargeable secondary batteries.

  A major reason for hindering the conventional metal-air battery from being a secondary battery is that the discharge voltage is relatively low, whereas the charge voltage is relatively high, so that the charge / discharge energy efficiency is low. In this regard, the following techniques are disclosed in Patent Documents 1 and 2.

  Patent Document 1 discloses a configuration using a positive electrode using a solid electrolyte that suppresses permeation of water vapor from outside air into the battery in a lithium air battery.

  Patent Document 2 discloses a lithium-air secondary battery in which a high discharge capacity can be obtained by enclosing pressurized oxygen in a battery case with oxygen having a water content of 1000 ppm or less.

  Patent Document 3 discloses a lithium-air battery using a water-based electrolyte, in which the positive electrode is a carbon-based material having porosity and adding manganese oxide or the like as a catalyst.

  Patent Document 4 discloses an air secondary battery using an aqueous solvent, in which the air electrode catalyst includes an alloy such as Mn supported by carbon.

JP 2011-096586 A JP 2001-273935 A JP 2012-033490 A JP 2012-015016 A

  The lithium-air battery described in Patent Document 1 uses a solid electrolyte that does not transmit water between the positive electrode and the negative electrode. In order to obtain a lithium-air battery with a high current density, the positive electrode is exposed to the atmosphere, so the activity of the negative electrode may be lost due to water in the atmosphere. A solid electrolyte impermeable to water was used. This pays attention to the water | moisture content to a negative electrode.

  On the other hand, the oxygen lithium battery described in Patent Document 2 encloses pressurized oxygen in a sealed battery container because of its high battery capacity. For the cycle life, the water content of the enclosed oxygen was set to 1000 ppm or less. As a secondary battery, oxygen is released during charging. Since the oxygen partial pressure is high, the charging voltage is high, and the charge / discharge efficiency is considered to decrease. This pays attention to the water | moisture content in oxygen gas.

  The air batteries described in Patent Documents 3 and 4 are not based on a non-aqueous system.

  An object of the present invention is to provide a carbon material for a metal-air secondary battery capable of improving charge / discharge energy efficiency by focusing on the positive electrode of a non-aqueous air battery.

The carbon material for a metal-air secondary battery of the present invention is mainly composed of carbon, and the amount of H ₂ O desorbed when heated to 50 ° C. or higher in the temperature programmed desorption gas analysis is 3.0 × 10 on a surface area basis. It is characterized by being ⁻⁷ mol / m ² or less.

  ADVANTAGE OF THE INVENTION According to this invention, the improvement of the charge / discharge energy efficiency in a metal air secondary battery can be achieved.

It is a schematic cross section which shows the metal air secondary battery of an Example. It is a schematic diagram which shows the positive electrode member of the metal air secondary battery of an Example. It is a schematic diagram which shows the fine structure of the positive electrode member of FIG. 2A. It is a graph which shows the charging / discharging characteristic of an Example and a comparative example. It is a graph which shows the result of the temperature-programmed desorption gas analysis of an Example and a comparative example.

  Hereinafter, a carbon material for a metal air secondary battery according to an embodiment of the present invention, a positive electrode member for a metal air secondary battery and a metal air secondary battery using the same will be described.

The carbon material for a metal-air secondary battery is mainly composed of carbon, and the amount of H ₂ O desorbed when heated to 50 ° C. or higher in the temperature programmed desorption gas analysis is 3.0 × 10 ^{−7 on a} surface area basis. and characterized in that mol / ^{m 2} or less.

The carbon material for a metal-air secondary battery desirably has the above H ₂ O content of 1.0 × 10 ⁻⁷ mol / m ² or less on a surface area basis.

  The carbon material for a metal-air secondary battery is preferably synthesized by a thermal decomposition method, a gas activation method, or an alkali activation method.

  The positive electrode member for a metal-air secondary battery is formed by mixing a catalyst having a function of ionizing oxygen, a binder, and a carrier, and applying the mixture to a base material. It is a carbon material for a metal-air secondary battery.

  In the metal-air secondary battery positive electrode member, the catalyst is Fe, Mn, Si, Cu, Sn, Ti, V, Mo, Nb, Ag, Ce or Zr oxide or nitride, or Pt, Au, Pd. , Ru, Rh or Os or an oxide thereof or a salt thereof is desirable.

  In the positive electrode member for a metal-air secondary battery, the binder is preferably polyvinylidene fluoride, polytetrafluoroethylene, or styrene butadiene rubber.

  The metal-air secondary battery includes a negative electrode member that occludes and releases metal ions and the positive electrode member for the metal-air secondary battery, and between the negative electrode member and the positive electrode member for the metal-air secondary battery, A layer containing an electrolyte is disposed.

  In the metal-air secondary battery, the layer containing an electrolyte preferably includes a separator, and the electrolyte is preferably impregnated in the separator as an electrolytic solution dissolved in a nonaqueous solvent.

  In the metal-air secondary battery, the negative electrode member preferably occludes and releases ions of a metal selected from the group consisting of Li, Na, Ca, Mg, Zn, Al, and Fe.

  Hereinafter, a metal-air secondary battery according to an embodiment of the present invention will be described with reference to the drawings and tables.

  FIG. 1 is a schematic view showing a cross section of a metal-air secondary battery according to an embodiment of the present invention. This metal-air secondary battery is a lithium-air secondary battery having a joint structure cell using metal lithium (Li) as a negative electrode.

  The metal-air secondary battery (cell) shown in FIG. 1 includes a positive electrode member 1, a negative electrode member 3, and a separator 2 disposed between them. The separator 2 is impregnated with an electrolytic solution. An O-ring 4 is disposed around the negative electrode member 3 that is metallic lithium. This cell is fixed in a state of being sandwiched between the pressing plate 5 and the current collector 6 by the clamping force that the pressing plate 5 receives from the clamping spring 7. Between the current collector 6 and the oxygen sealing valve 8, oxygen gas acting as a positive electrode active material is sealed.

The negative electrode member 3 occludes and releases metal ions of the electrolytic solution impregnated in the separator 2. In the present embodiment, disc-shaped metallic lithium having a diameter of 8 mm and a thickness of 1 mm is used as the negative electrode member 3. The electrode area of the negative electrode member 3 can be defined as the area of the metallic lithium in contact with the separator 2 and is about 0.5 cm ² . The separator 2 was a disc-shaped polyethylene having a diameter of 13 mm larger than that of the negative electrode member 3.

  The positive electrode member 1 ionizes oxygen which is a positive electrode active material.

  In the metal-air secondary battery of FIG. 1, a discharge reaction represented by the following reaction formulas (1) to (3) is performed during discharge.

(Negative electrode side) 2Li → 2Li ⁺ + 2e ⁻ (1)
(Positive electrode side) O ₂ + 2Li ⁺ + 2e ⁻ → Li ₂ O ₂ (2)
(Total reaction) 2Li + O ₂ → Li ₂ O ₂ (3)
On the other hand, during charging, a charging reaction represented by the following reaction formulas (4) to (6) is performed.

(Negative ^{electrode) 2Li ← 2Li + + 2e -} ... (4)
(Positive electrode side) O ₂ + 2Li ⁺ + 2e ⁻ ← Li ₂ O ₂ (5)
(Total reaction) 2Li + O ₂ ← Li ₂ O ₂ (6)
FIG. 2A is a schematic diagram illustrating the configuration of the positive electrode member 1.

  As shown in the figure, the positive electrode member 1 is formed by mixing a catalyst 1b, a binder 1c, and a carrier 1d and applying the mixture to a substrate 1a. In this embodiment, the catalyst 1b, the binder 1c, and the carrier 1d are mixed at a weight ratio of 5: 4: 1, respectively, and applied to the substrate 1a to obtain the positive electrode member 1.

  FIG. 2B is a partially enlarged view of the positive electrode member 1 of FIG. 2A.

  In this figure, the catalyst 1b, the binder 1c, and the carrier 1d applied to the substrate 1a are shown.

The base material 1a is a conductive substance that mainly constitutes the positive electrode member 1, and for example, carbon or metal is used. As the base material 1a, a material having a large specific surface area (for example, 100 m ² / g or more) and high electrical conductivity is preferable. For example, activated carbon, a metal porous body, etc. can be used as the base material 1a.

The catalyst 1b is a powdery substance that assists the reaction of the above reaction formula (2) and the above reaction formula (5) on the positive electrode side, thereby improving the discharge voltage and lowering the charge voltage. As the catalyst 1b, an oxide such as MnO ₂ is used.

  The carrier 1d has a function of supporting the catalyst 1b on the substrate 1a. The binder 1c has a function of binding the substrate 1a, the catalyst 1b, and the carrier 1d to each other. The details of the substances used as the catalyst 1b, the binder 1c, and the carrier 1d will be described in each example described later.

  The size of the positive electrode member 1 is preferably smaller than the separator 2 described above and larger than the negative electrode member 3. That is, these sizes can be set so that the separator 2 is the largest, and the positive electrode member 1 and the negative electrode member 3 become smaller in this order.

LiPF ₆ was used as the electrolyte. The electrolytic solution is obtained by dissolving 1 mol of LiPF ₆ in propylene carbonate, which is a non-aqueous solvent. This was used by impregnating the separator 2.

  After dropping about several drops of the electrolyte on the surface of the positive electrode member 1 and the surface of the negative electrode member 3, the separator 2 is sandwiched between the positive electrode member 1 and the negative electrode member 3 with these surfaces facing inside, so that The separator 2 was impregnated with the liquid.

  The current collector 6 is a stainless steel mesh having a thickness of 1 mm. In addition, when the base material 1a is made of a metal porous body in the positive electrode member 1 as described above, it can also be used as the current collector 6.

  The holding plate 5 is made of stainless steel, and biases the negative electrode member 3 and the O-ring 4 in the direction of the separator 2 in accordance with the fastening force received from the fastening spring 7. Thereby, it was set as the structure where the negative electrode member 3, the separator 2, and the positive electrode member 1 contact | adhere mutually.

  In this embodiment, the oxygen sealing valve 8 is opened, and oxygen gas having a concentration of 99.9% is allowed to flow from the outside of the current collector 6 into the cell by flowing at a flow rate of 500 ml / min for about 10 to 15 minutes. . Thereafter, oxygen gas was sealed inside the cell by closing the oxygen sealing valve 8.

  The metal-air secondary battery as described above was assembled in a glove box.

  Next, details of the catalyst 1b, the binder 1c, and the carrier 1d will be described.

  In this embodiment, manganese dioxide was used as the catalyst 1b, and polyvinylidene fluoride (PVDF) was used as the binder 1c. A carbon material was used as the carrier 1d. Since the carrier 1d is used as an electrode material, excellent electrical conductivity is required.

At the time of discharge, as shown in the reaction formula (2), the discharge product Li ₂ O ₂ is formed on the surface of the positive electrode. The greater the amount of this product, the higher the discharge capacity. Moreover, at the time of charge, as shown in the above reaction formula (5), the discharge product Li ₂ O ₂ is decomposed. It is considered that the smaller the Li ₂ O ₂ particles or the lower the film thickness of the Li ₂ O ₂ layer formed on the positive electrode surface, the easier it is to decompose Li ₂ O ₂ and to charge it. Therefore, it is preferable to use a carbon material having a large specific surface area from the viewpoint of forming Li ₂ O ₂ having a large volume as small particles or a thin film on the positive electrode surface. Generally, the specific surface area of the carbon material used for a metal air battery is 100 m < ² > / g or more.

  Specific examples thereof will be described using Examples 1 to 3.

  In Example 1, the positive electrode member 1 was produced by the following method using the activated carbon 1 as the carrier 1d.

  First, synthesis of the activated carbon 1 will be described.

Coconut shell charcoal as a raw material was dried and carbonized at 700 ° C. Thereafter, activated carbon 1 was obtained by activating the water vapor gas at 1000 ° C. or less with the carbonized raw material. The specific surface area measured by the nitrogen adsorption BET method was about 2100 m ² / g.

  The activated carbon 1 was uniformly mixed with manganese dioxide as the catalyst 1b.

  Next, an N-methyl-2-pyrrolidone (NMP) solution of PVDF, which is the binder 1c, is added to this mixture and sufficiently stirred to prepare a slurry, which is applied to the substrate 1a to form a positive electrode. Member 1 was produced.

  The positive electrode member 1 produced as described above was dried in an air atmosphere at 80 ° C. for about 1 hour to evaporate NMP, and then further vacuum dried at 120 ° C. for about 3 hours to evaporate moisture. Thus, the metal-air secondary battery shown in FIG.

  In Example 2, activated carbon 2 was used as the carrier 1d.

  The synthesis of activated carbon 2 will be described.

After mixing graphitizable coal coke as a raw material and potassium hydroxide (KOH), the mixture was heated and activated. It refine | purified using an acid and a pure water, and it dried and obtained the activated carbon 2. The specific surface area measured by the nitrogen adsorption BET method was about 2300 m ² / g.

  A positive electrode member 1 was produced in the same manner as in Example 1 except that the activated carbon 2 was used as the carrier 1d.

  In Example 3, conductive carbon black was used as the carrier 1d.

  First, the synthesis of conductive carbon black will be described.

Conductive carbon black was produced by a thermal decomposition reaction at 500 ° C. to 2000 ° C. using a mixed raw material containing acetylene gas, hydrocarbon, and carbon nanotube-forming catalyst as a raw material. This conductive carbon black was collected by a collecting device such as a cyclone. This conductive carbon black had a specific surface area of about 800 m ² / g by nitrogen adsorption BET method.

Next, this conductive carbon black was placed in an atmosphere in which argon (Ar) and hydrogen (H ₂ ) were mixed at a volume ratio of 97: 3 and treated at 400 ° C. for 3 hours.

  Next, a positive electrode member 1 was produced in the same manner as in Example 1 except that conductive carbon black treated at 400 ° C. was used as the carrier 1d.

(Comparative example)
In Comparative Example, except that the conductive carbon black synthesized by the thermal decomposition reaction of Example 3 was used as the support 1d without being treated in an atmosphere in which argon (Ar) and hydrogen (H ₂ ) were mixed, as it was. In the same manner as in Example 3, a positive electrode member 1 was produced.

  Next, experimental results regarding the charge / discharge evaluation of the metal-air secondary battery will be described.

  In the experiments for charge / discharge evaluation, each metal-air secondary battery according to Examples 1 to 3 and a comparative metal-air secondary battery using conductive carbon black without treatment as a carrier 1d were used. Note that the metal-air secondary battery of the comparative example is different from the above using the conductive carbon black without treatment, and the other points are the same as in the third embodiment.

About each metal-air secondary battery of Examples 1-3 and a comparative example, the energy density and average voltage at the time of charge and discharge were measured, respectively, and charging / discharging energy efficiency was calculated | required based on the measurement result. Charging and discharging conditions at this time, the electrode area and 0.5 cm ² as described above, the discharge time is a constant current discharge of 0.1 mA / cm ^2, the constant current charging at the time of charging is 0.02 mA / cm ² Went. Further, both the charge capacity and the discharge capacity were set to 100 Ah / kg, and the charge or discharge was terminated when the charge capacity and the discharge capacity were exceeded.

  In this experiment, each of the metal-air secondary batteries of Examples 1 to 3 and the comparative example was installed in a desiccator with a terminal, and after argon gas was sealed inside the desiccator, charge / discharge evaluation was performed on the outer terminal of the desiccator. The measurement was performed by attaching to the apparatus.

  FIG. 3 shows a charge / discharge characteristic graph obtained by graphing changes in battery capacity and charge / discharge voltage during charge / discharge obtained by this experiment. The horizontal axis represents battery capacity, and the vertical axis represents charging voltage or discharging voltage. In this figure, Examples 1-3 and the comparative example are shown.

  In addition, the four types of carbon materials used as the carrier 1d in Examples 1 to 3 and the comparative example were subjected to temperature programmed desorption gas analysis under vacuum. In this analysis, when the carbon sample was raised from 50 ° C. to 1000 ° C. at a heating rate of 10 ° C./min, the amount of desorbed gas was measured.

  FIG. 4 is a graph showing the results of thermal desorption gas analysis of the carbon material used as the carrier 1d for Examples 1 to 3 and Comparative Example. The horizontal axis represents temperature, and the vertical axis represents the temperature-programmed desorption gas amount.

Table 1 shows the energy density, charge / discharge energy efficiency, average charge / discharge voltage, and desorbed H ₂ O amount of Examples 1 to 3 and Comparative Example obtained by this experiment.

When comparing Examples 1 to 3 and the comparative example in FIG. 3, these carbon materials having a small amount of temperature-programmed desorption H ₂ O as compared with the case of using conductive carbon black as in the comparative example are used as the support 1d. It can be seen that the discharge voltages are improved in Examples 1 to 3 used in the above. Furthermore, it turns out that the charge voltage of Examples 1-3 is low compared with a comparative example. Therefore, in Examples 1-3, charge / discharge energy efficiency higher than a comparative example can be obtained.

In addition, when Examples 1 to 3 are compared with the comparative example in FIG. 4, in the comparative example, the temperature-programmed desorption H ₂ O amount reaches a maximum value of 5.7 × 10 ⁻¹⁰ mol / m ² at 160 ° C. The integrated amount of H ₂ O desorbed at from 1000 to 1000 ° C. is as high as 1.38 × 10 ⁻⁷ mol / m ² . On the other hand, the amount of H ₂ O desorbed near 160 ° C. in Examples 1 to 3 is 1.0 × 10 ⁻¹⁰ mol / m ² or less, and H ₂ O desorbed to 50 ° C. to 1000 ° C. Is less than half that of conductive carbon black.

There are two main sources of H ₂ O desorbed by temperature. It is due to H ₂ O adhering to the surface of the carbon material and due to decomposition of the surface functional group (—COOH) of the carbon. In general, under vacuum, a water desorbed H _{2 O} is attached to the surface in 90 ° C. or less, the desorbed H _{2 O} at a wide temperature range above 90 ° C. mainly decomposition of surface functional groups (-COOH) Is due to.

From the above, it was found that the lower the temperature-programmed desorption H ₂ O amount, the lower the charging voltage. There are at least two mechanisms for this phenomenon.

  1. Moisture adhering to the surface of the carbon material.

When adhering water is present on the carbon surface, the theoretical reaction products Li ₂ O ₂ and H ₂ O as shown in the above reaction formula (3) react to form LiOH. When charging, about 4.0 V is required to decompose LiOH. Therefore, it appears when the charging voltage of the Li air battery is high.

  Second, surface functional groups of carbon materials.

For example, when —COOH is present, it reacts with a theoretical product during discharge, and Li ₂ CO ₃ is generated according to the following reaction formula (7).

2Li ₂ O ₂ + 2R—COOH → 2Li ₂ CO ₃ + O ₂ + 2R—H
... (7)
Since Li ₂ CO ₃ has a high theoretical decomposition voltage of 3.8 V, it appears when the charging voltage of the Li air battery is high.

In the metal-air battery, since discharge products are formed on the surface of the carrier, the influence of moisture and functional groups attached to the surface contributes to the amount of moisture and functional groups per specific surface area. Therefore, temperature-programmed desorption H ₂ O per area of the carbon material is an important parameter.

According to the above experimental results, it is possible to achieve an improvement in charge / discharge energy efficiency in a metal-air secondary battery by using a carbon material with a small amount of temperature-programmed desorption H ₂ O under vacuum as in Examples 1 to 3. I understand.

  Moreover, although the carbon material of Examples 1-3 was different in the synthesis method, the charging voltage could be similarly reduced and the charge / discharge energy efficiency could be improved. The effect of reducing the charging voltage does not depend on the carbon material synthesis method.

According to the above embodiment, the metal-air secondary battery is disposed between the negative electrode member 3 that occludes and releases lithium ions, the positive electrode member 1 that ionizes oxygen, and the negative electrode member 3 and the positive electrode member 1. The positive electrode member 1 includes a carbon material having a low amount of temperature-programmed desorption H ₂ O. The metal-air secondary battery having such a configuration can achieve improvement in charge / discharge energy efficiency.

In the above embodiment, an example in which a carbon material with a small amount of temperature-programmed desorption H ₂ O is used as the carrier 1d as in Examples 1 to 3 has been described. The same high charge / discharge energy efficiency can be obtained.

Moreover, in the above embodiment, an example has been described using a Atsushi Nobori H _{2 O} amount is less carbon material as the positive electrode member, also be used as Atsushi Nobori H _{2 O} amount of the positive electrode is small The same high charge / discharge energy efficiency can be obtained.

Furthermore, the amount of H ₂ O desorbed per area of the carbon material for metal-air batteries was calculated from the specific surface area measured by the BET method. Since there is variation in specific surface area measurement by the BET method, the integrated amount of the heated desorption H ₂ O at 50 ° C. to 1000 ° C. under vacuum is 3.0 × 10 ⁻⁷ mol / m ^{2 based on} the surface area of the carbon material. The following is preferred.

  In the above embodiment, the catalyst 1b is composed of an oxide or nitride such as Fe, Mn, Si, Cu, Sn, Ti, V, Mo, Nb, Ag, Ce, Zr, or Pt, Au, Pd, Ru. , Rh, Os and the like or their oxides or salts thereof.

  From the viewpoint of cost reduction, the content of noble metal elements is reduced as much as possible, and many oxides or nitrides such as Fe, Mn, Si, Cu, Sn, Ti, V, Mo, Nb, Ag, Ce, and Zr are used. It is more preferable to do.

In the above embodiment, the example in which the separator 2 is impregnated with an electrolytic solution using LiPF ₆ as an electrolyte and propylene carbonate as a solvent has been described. An aqueous electrolyte may be used. That is, as a solvent other than propylene carbonate, for example, ethylene carbonate, butylene carbonate, vinylene carbonate, γ-butyrolactone, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, 1,2-dimethoxyethane, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, methyl propionate, ethyl propionate, phosphoric acid triester, trimethoxymethane, dioxolane, diethyl ether, sulfolane, 3-methyl-2-oxazolidinone, tetrahydrofuran, 1,2-di Ethoxyethane, chloroethylene carbonate, chloropropylene carbonate and the like can be used. Of these, it is more preferable to use a cyclic compound having a high boiling point as a solvent.

  Further, a solid electrolyte held in a polymer such as ethylene oxide, acrylonitrile, vinylidene fluoride, methyl methacrylate, hexafluoropropylene, an ionic liquid, or the like may be used instead of the non-aqueous electrolyte.

Further, as the electrolyte other than LiPF ₆ , another electrolyte used in a general lithium ion secondary battery or the like may be used. For _example, can be used as _{LiBF 4, LiClO 4, LiCF 3} SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiTFSI such an electrolyte. Alternatively, a lithium salt such as an imide salt of lithium represented by lithium trifluoromethanesulfonimide can also be used as the electrolyte.

  Alternatively, a gel electrolyte obtained by impregnating a polymer such as ethylene oxide, acrylonitrile, vinylidene fluoride, methyl methacrylate, hexafluoropropylene with a nonaqueous electrolytic solution may be used.

  In the above embodiment, the example in which the negative electrode member 3 occludes and releases lithium ions by using metallic lithium as the negative electrode member 3 has been described. However, the negative electrode member 3 occludes and releases other metal ions. May be. For example, by using a metal such as Na, Ca, Mg, Zn, Al, or Fe as the negative electrode member 3, the negative electrode member 3 can occlude and release these ions.

  A carbon material that occludes lithium ions can also be used for the negative electrode member 3.

  In the above-described embodiment, an example in which PVDF is used as the binder 1c has been described. However, another binder (binder) used in a general lithium ion secondary battery or the like may be used. For example, fluorine resin such as polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), or the like can be used as the binder 1c.

  In the above embodiment, an example in which polyethylene is used for the separator 2 has been described. However, other materials used in a general lithium ion secondary battery or the like may be used. For example, the separator 2 can be configured using a porous separator such as polypropylene or a glass ceramic having metal ion conductivity.

  In said embodiment, although the example using the cell of a joint structure was demonstrated, the form of a cell is not limited to this. For example, a laminate type or cylindrical type cell can also be used. That is, the present invention does not depend on the cell form as long as the reaction of the metal-air secondary battery can be confirmed.

  1: positive electrode member, 1a: base material, 1b: catalyst, 1c: binder, 1d: carrier, 2: separator, 3: negative electrode member, 4: O-ring, 5: holding plate, 6: current collector, 7: tightening Spring, 8: oxygen-filled valve.

Claims (9)

The main component is carbon, and the amount of H ₂ O desorbed when heated to 50 ° C. or higher in the temperature programmed desorption gas analysis is 3.0 × 10 ⁻⁷ mol / m ² or less on the surface area basis. Carbon material for rechargeable metal-air batteries. _{2. The} carbon material for a metal-air secondary battery according to claim 1, wherein the amount of H ₂ O is 1.0 × 10 ⁻⁷ mol / m ² or less on a surface area basis.   The carbon material for a metal-air secondary battery according to claim 1 or 2, synthesized by a thermal decomposition method, a gas activation method, or an alkali activation method.   A positive electrode member formed by mixing a catalyst having a function of ionizing oxygen, a binder, and a carrier and applying the mixture to a base material, wherein the carrier is any one of claims 1 to 3. A positive electrode member for a metal-air secondary battery, characterized in that it is a carbon material for a metal-air secondary battery.   The catalyst is an oxide or nitride of Fe, Mn, Si, Cu, Sn, Ti, V, Mo, Nb, Ag, Ce or Zr, or Pt, Au, Pd, Ru, Rh or Os or an oxide thereof. Or the salt is included, The positive electrode member for metal air secondary batteries of Claim 4 characterized by the above-mentioned.   The positive electrode member for a metal-air secondary battery according to claim 4 or 5, wherein the binder is polyvinylidene fluoride, polytetrafluoroethylene, or styrene butadiene rubber.   A negative electrode member that occludes and releases metal ions and a positive electrode member for a metal-air secondary battery according to any one of claims 4 to 6, wherein the negative electrode member and the positive electrode member for the metal-air secondary battery, A metal-air secondary battery characterized in that a layer containing an electrolyte is disposed between them.   The metal-air secondary battery according to claim 7, wherein the layer containing the electrolyte includes a separator, and the electrolyte is impregnated in the separator as an electrolytic solution dissolved in a nonaqueous solvent.   The metal air secondary according to claim 7 or 8, wherein the negative electrode member occludes and releases ions of a metal selected from the group consisting of Li, Na, Ca, Mg, Zn, Al, and Fe. battery.

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