JP2015122295A - Lithium air battery and negative electrode composite for lithium air battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact lithium air battery that can be suppressed from extremely increasing in size compared with a conventional air battery even if increasing energy density and input/output density and a negative electrode composite for the lithium air battery.SOLUTION: A lithium air battery 1 comprises: a negative electrode composite 8A which comprises a plate-shaped or line-shaped negative electrode collector 5, two plate-shaped negative electrode layers 15 that are made of alloy mainly composed of metal lithium and lithium or of a chemical substance mainly composed of lithium and pinch a part of the negative electrode collector 5, two plate-shaped isolation layers 12 having lithium ion conductivity that sandwich the whole of the two negative electrode layers 15 and gaskets 18 that are arranged between the two isolation layers 12 to surround the two negative electrode layers 15 and seal a space between the two isolation layers 12; and an air electrode 9 that comprises an air electrode layer 13 which contains a conductive material and opposes to at least either one of the two isolation layers and a plate-shaped or line-shaped air electrode collector 6 electrically connected to the air electrode layer 13.

Description

  The present invention relates to a lithium-air battery and a negative electrode composite of the lithium-air battery.

  Due to the widespread use of electric vehicles, there are expectations for air batteries having a much higher energy density than lithium ion batteries. The air battery uses oxygen in the air as a positive electrode active material.

  By the way, a lithium-air battery that uses metallic lithium, an alloy containing lithium as a main component, or a compound containing lithium as a main component is known as an anode active material. Focusing on the type of electrolyte, lithium-air batteries are broadly divided into two types: aqueous electrolytes and nonaqueous electrolytes. Non-aqueous electrolyte lithium-air batteries have become the mainstream of research and development because they can utilize the technology of lithium-ion batteries other than the air electrode.

  On the other hand, research and development of an aqueous electrolyte-based lithium-air battery is also in progress, although the number is still small. Compared to lithium water batteries of non-aqueous electrolytes, lithium air batteries of aqueous electrolytes have advantages such as being not affected by moisture in the air and being inexpensive and non-combustible. However, metallic lithium, which is a negative electrode active material, reacts when directly in contact with oxygen or water. Therefore, in an aqueous electrolyte-type lithium-air battery, it is necessary to provide a protective layer such as a lithium ion conductive solid electrolyte in order to protect metallic lithium from the atmosphere or an aqueous solution.

  Therefore, a buffer layer of a polymer electrolyte is formed on one surface of the plate-shaped metallic lithium, and the one surface of the buffer layer of the polymer electrolyte is water resistant having lithium ion conductivity (also expressed as lithium ion conductivity or lithium ion conductivity). A lithium air battery including a negative electrode composite covered with glass ceramics as a layer is known (see, for example, Patent Document 1 and Non-Patent Document 1).

JP 2010-192313 A

Yasuo Takeda, Masayuki Imanishi, Osamu Yamamoto, “Current Status and Problems of Aqueous Lithium / Air Battery”, GS Yuasa Technical Report, June 2010, Vol. 7, No. 1, p. 1-6

  In the conventional air battery described in Patent Document 1 and Non-Patent Document 1, one surface of one air electrode faces one surface of one negative electrode composite and is enclosed in a container or a laminate film. When these input / output densities (output per weight) are increased, these conventional air batteries simply use a large number of air batteries having the same structure, or simply increase the size of the air battery having the same structure. However, simply using a large number of air batteries with the same structure or simply increasing the size of the air battery with the same structure is installed in an electric vehicle in order to increase the required air battery mounting space inefficiently and greatly. In some cases, it is difficult to adopt in reality.

  The conventional air battery described in Non-Patent Document 1 encloses the negative electrode composite in a gas barrier laminate film having a three-layer structure of polypropylene (PP), aluminum foil, and polyethylene terephthalate (PET). The negative electrode composite of Non-Patent Document 1 closes the opening made in the laminate film with glass ceramics as a window material having lithium ion conductivity in order to ensure lithium ion conductivity inside and outside the laminate film.

  However, it is difficult to bond a combination of polypropylene (PP) as a laminate film and glass ceramics as a negative electrode composite with an adhesive, and lack durability. In addition, in order to form a negative electrode composite by thermally welding the laminate film, a welding margin of about 10 mm is required on the outer peripheral edge of the laminate film. As a result, the area of the laminate film is increased and the volume of the air battery is increased. To increase.

  In other words, the conventional air battery discloses a small single cell for experimentation, and it is difficult to construct a compact practical cell with increased battery characteristics, particularly energy density. In order to improve the battery characteristics of the lithium-air battery, in addition to the material for establishing the lithium-air battery, a technique for increasing the discharge voltage by reducing the size and weight and reducing the internal resistance is required.

  Accordingly, the present invention provides a compact lithium-air battery and a negative-electrode composite of a lithium-air battery that can suppress an extreme increase in size even when the energy density and input / output density are increased as compared with a conventional air battery. Objective.

  In order to solve the above problems, a lithium-air battery according to the present invention includes a negative electrode composite and an air electrode, and the negative electrode composite includes a plate-like or linear negative-electrode current collector, metallic lithium, and lithium. Two negative electrode layers made of an alloy mainly containing lithium or a compound mainly containing lithium sandwiching a part of the negative electrode current collector, and made of glass ceramics having lithium ion conductivity and made of the negative electrode current collector Two isolation layers having a plate shape sandwiching the other part of the body and all of the two negative electrode layers, and the two isolation layers while exposing the remainder of the negative electrode current collector to the outside between the two isolation layers A joint portion that joins and closes the outer peripheral edge portions of the air electrode, and the air electrode includes an air electrode layer containing a conductive material and facing at least one of the two isolation layers; and the air electrode layer Plate or wire connected electrically And a Kikyoku collector.

  The negative electrode composite of the lithium-air battery according to the present invention includes a plate-like or linear negative-electrode current collector, metal lithium, an alloy containing lithium as a main component, or a compound containing lithium as a main component. Two plate-shaped negative electrode layers sandwiching a part of the current collector, another part of the negative electrode current collector made of glass ceramics having lithium ion conductivity, and a plate shape sandwiching all of the two negative electrode layers The two isolation layers, and a junction part that joins and closes the outer peripheral edges of the two isolation layers while exposing the remaining part of the negative electrode current collector to the outside of the two isolation layers.

  In another embodiment, the lithium-air battery according to the present invention is a negative electrode current collector made of a plate-like or linear negative electrode current collector and metallic lithium, an alloy containing lithium as a main component, or a compound containing lithium as a main component. Two plate-shaped negative electrode layers sandwiching a part of the electric body, two plate-shaped isolation layers having lithium ion conductivity sandwiching all of the two negative electrode layers, and surrounding the two negative electrode layers A negative electrode composite provided with a gasket disposed between the two isolation layers and sealing a space between the two isolation layers; and an air electrode layer containing a conductive material and facing at least one of the two isolation layers And an air electrode including a plate-like or linear air electrode current collector electrically connected to the air electrode layer.

  In another form, the negative electrode composite of the lithium-air battery according to the present invention is made of a plate-like or linear negative electrode current collector, metal lithium, an alloy containing lithium as a main component, or a compound containing lithium as a main component. Two plate-shaped negative electrode layers sandwiching a part of the negative electrode current collector, two plate-shaped isolation layers having lithium ion conductivity sandwiching all of the two negative electrode layers, and the two negative electrode layers And a gasket that is disposed between the two isolation layers so as to surround the space and seals a space between the two isolation layers.

  ADVANTAGE OF THE INVENTION According to this invention, compared with the conventional air battery, even if it increases energy density and input / output density, the compact lithium air battery which can suppress an extreme enlargement, and the negative electrode composite body of a lithium air battery can be provided.

1 is a schematic perspective view showing a lithium air battery according to an embodiment of the present invention. The schematic perspective view which shows the internal structure of the lithium air battery which concerns on embodiment of this invention. The circuit diagram which shows the lithium air battery which concerns on embodiment of this invention. The schematic perspective view which shows the other example of the internal structure of the lithium air battery which concerns on embodiment of this invention. The schematic perspective view which shows the negative electrode composite_body | complex of the lithium air battery which concerns on embodiment of this invention. 1 is a schematic cross-sectional view showing a negative electrode composite of a lithium air battery according to an embodiment of the present invention. Schematic sectional drawing which shows the other example of the negative electrode composite_body | complex of the lithium air battery which concerns on embodiment of this invention. Schematic sectional drawing which shows the other example of the negative electrode composite_body | complex of the lithium air battery which concerns on embodiment of this invention. The perspective view explaining the state which the negative electrode composite_body | complex of the cell of Example 1 decomposed | disassembled, and the assembled state. The perspective view explaining the state which the cell of the comparative example 1 decomposed | disassembled. The graph which shows transition of the discharge voltage of the cell of Example 1 and Comparative Example 1. FIG. The graph which shows an impedance spectrum. The graph which shows transition of the discharge voltage of the cell of Example 2 and Example 3. FIG.

  Embodiments of a lithium air battery and a negative electrode composite body of the lithium air battery according to the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic perspective view showing a lithium-air battery according to an embodiment of the present invention.

  The lithium air battery 1 is charged and discharged. As shown in FIG. 1, a lithium-air battery 1 according to this embodiment includes a case 2 as an outer shell, a negative electrode current collector 5 that is pulled out from the case 2 and exposed, and an air electrode as a positive electrode current collector. Current collector 6.

  Case 2 is a gas-permeable, liquid-impermeable material such as polyethylene, polypropylene, or a fluororesin molded product made of a fluoropolymer having a vinylidene fluoride unit and a tetrafluoroethylene unit, or a vinylidene fluoride unit. And a fluororesin porous body composed of a fluoropolymer having a tetrafluoroethylene unit, which is a hexahedron, for example, a hollow body having a rectangular parallelepiped shape. The case 2 may be a molded product made of a material that is impermeable to gas and liquid. In this case, a vent is provided on the side wall of the case 2. The vent is provided at a position where the electrolyte 7 described later does not leak out, and allows air to flow inside and outside the case.

  Only the negative electrode current collector 5 and the air electrode current collector 6 are exposed outside the case 2.

  FIG. 2 is a schematic perspective view showing the internal structure of the lithium-air battery according to the embodiment of the present invention.

  FIG. 3 is a circuit diagram showing a lithium-air battery according to an embodiment of the present invention.

  The adjacent negative electrode composite 8 and the air electrode 9 are actually in contact with each other, but are separated from each other in FIG. 2 for easy identification.

  As shown in FIGS. 2 and 3, the lithium-air battery 1 according to this embodiment includes a case 2 that houses a negative electrode composite 8 and an air electrode 9, and a plurality of negative electrode composites that are alternately stacked. 8 and a plurality of air electrodes 9, and an electrolyte 7 stored in the case 2 and in contact with at least the air electrode 9 and responsible for lithium ion conduction between the air electrode 9 and the negative electrode composite 8.

  One surface of the negative electrode composite 8 and one surface of the air electrode 9 facing the same are one air battery cell 11. That is, the lithium-air battery 1 is obtained by connecting the number of air battery cells 11 facing the negative electrode composite 8 and the air electrode 9 in parallel.

  Each of the plurality of negative electrode composites 8 and the plurality of air electrodes 9 has a plate shape. The plurality of negative electrode composites 8 and the plurality of air electrodes 9 are electrically connected in parallel, respectively.

  The air electrode 9 exhibits a larger projected area than the negative electrode composite 8. Specifically, it has a quadrilateral shape that is slightly larger than the negative electrode composite body 8 having a quadrangular flat plate shape.

  The air electrode 9 contains a conductive material and is electrically connected to the air electrode layer 13 and the air electrode layer 13 facing at least one surface of the negative electrode composite 8 (that is, one surface of the isolation layer 12 described later). And a plate-like or linear air electrode current collector 6 connected to.

The air electrode layer 13 is made of a conductive material such as carbon fiber and has a thin plate shape. Specifically, the air electrode layer 13 has a porous structure, for example, a mesh structure in which constituent fibers are regularly arranged, a nonwoven fabric structure in which random arrangement is made, and a three-dimensional network structure. Specifically, carbon materials such as carbon cloth, carbon non-woven fabric, and carbon paper. Further, as another material having a porous structure, for example, a metal material such as stainless steel, nickel, aluminum, or iron may be used. As a preferable material for the air electrode, a material having a light weight and high corrosion resistance is preferable, and an air electrode made of the carbon material described above is desirable. The air electrode layer 13 sucks up the electrolyte 7 by capillary action and interposes between the negative electrode composite 8 and the air electrode 9. The air electrode layer 13 may include a catalyst such as a noble metal or a metal oxide. The catalyst may be a catalyst that promotes an oxygen reduction reaction during discharging and an oxygen oxidation reaction during charging. For _{example, MnO 2, CeO 2, Co} 3 O 4, NiO, V 2 O 5, Fe 2 O 3, ZnO, CuO, La 1.6 Sr 0.4 NiO 4, La 2 NiO 4, La 0.6 Sr Metal oxidation such as _0.4 FeO ₃ , La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ , La _0.8 Sr _0.2 MnO ₃ , Mn _1.5 Co _1.5 O ₄ A noble metal such as Au, Pt, and Ag; and a composite thereof. The method of producing the air electrode layer 13 containing the catalyst is not particularly limited. For example, a carbon cloth carrying a catalyst metal such as platinum mixed with a binder (binder) and an organic solvent (slurry) is used. It can be carried out by adhering to. As the organic solvent, for example, N-methyl-2-pyrrolidone (NMP) acetonitrile, dimethylformamide (DMF), dimethylacetamide (DMA), and dimethyl sulfoxide (DMSO), acetone, ethanol, 1-propanol, etc. should be used. Can do. Examples of the binder include polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and the like. Specific examples of the method for attaching the catalyst to the air electrode 13 include a method for applying and attaching the slurry by the doctor blade method or the spray method.

  The air electrode current collector 6 may be present as long as it can exist stably in the operating range of the lithium-air battery and has the desired conductivity. Examples of the material of the air electrode current collector 6 include metal materials such as stainless steel, nickel, aluminum, gold, and platinum, and carbon materials such as carbon cloth and carbon nonwoven fabric.

  The electrolyte 7 is an aqueous electrolyte. The electrolyte 7 may also be in contact with the negative electrode composite 8. The aqueous electrolyte is, for example, an aqueous lithium chloride solution.

  Between the air electrode 9 and the negative electrode composite 8, a resin sheet or the like is arbitrarily disposed as a water retention layer. The water retention layer prevents direct contact between the air electrode and the negative electrode composite. The water retention layer is preferably a porous and / or foamable sheet impregnated / retained with an electrolyte, such as cellulose, chemical fiber nonwoven fabric, PP (polypropylene) resin, PE (polyethylene) resin, PI (polyimide) resin, etc. And a polymer film.

  The electrolyte 7 may be a polymer electrolyte. In this case, the electrolyte 7 is a thin film-like body sandwiched between the air electrode 9 and the negative electrode composite 8 or a film-like body that coats the surface of the air electrode layer 13.

  FIG. 4 is a schematic perspective view showing another example of the internal structure of the lithium-air battery according to the embodiment of the present invention.

  The adjacent negative electrode composite 8 and the air electrode 9A are actually in contact with each other, but are separated from each other in FIG. 4 for easy identification.

  In addition, the same code | symbol is attached | subjected to the same structure as the lithium air battery 1 in the lithium air battery 1A, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 4, the air electrode layer 13A of the air electrode 9A of the lithium-air battery 1A according to this embodiment is bent in a twisted manner. The plurality of negative electrode composites 8 are sandwiched between flat portions 13b between the folds 13a and the folds 13a of the air electrode layer 13A.

  One air electrode current collector 6 may be provided for one air electrode layer 13A sandwiching the plurality of negative electrode composites 8, and the number and total number of air electrode current collectors 6 are larger than those of the air electrode current collector 6 of the lithium-air battery 1. Extension length, weight, and volume can be reduced.

  FIG. 5 is a schematic perspective view showing a negative electrode composite of a lithium air battery according to an embodiment of the present invention.

  FIG. 6 is a schematic cross-sectional view showing a negative electrode composite of a lithium air battery according to an embodiment of the present invention.

  As shown in FIGS. 5 and 6, the negative electrode composite 8 of the lithium-air battery 1, 1 </ b> A includes a plate-like or linear negative electrode current collector 5, metal lithium, a lithium-based alloy, or lithium. Two plate-shaped negative electrode layers 15 made of a compound as a main component and sandwiching a part of the negative electrode current collector 5, another part of the negative electrode current collector 5 made of glass ceramics having lithium ion conductivity, and 2 Two plate-shaped isolation layers 12 sandwiching all of the negative electrode layers 15 and the outer peripheral edge portions of the two isolation layers 12 are joined while the remaining portion of the negative electrode current collector 5 is exposed to the outside between the two isolation layers 12 And a joint portion 16 to be closed.

  The negative electrode composite 8 includes a buffer layer 17 having lithium ion conductivity and separating the negative electrode layer 15 and the isolation layer 12.

  That is, the negative electrode composite 8 includes a packaging structure in which the two negative electrode layers 15 to be bonded are wrapped with the buffer layer 17, and the buffer layer 17 is wrapped with the two isolation layers 12 and the joint portion 16.

  The negative electrode current collector 5 may be made of any material as long as it can exist stably in the operating range of the lithium-air battery and has a desired conductivity. For example, copper, nickel, etc. can be mentioned.

  The two negative electrode layers 15 have substantially the same rectangular flat plate shape, and are joined with a part of the negative electrode current collector 5 being sandwiched. In the present embodiment, the negative electrode current collector 5 is formed by integrally forming a strip-shaped terminal portion on a rectangular plate-like portion having substantially the same size as the negative electrode layer 15. However, depending on the purpose, the negative electrode current collector 5 is not in contact with the entire opposing surfaces of the two negative electrode layers 15 but is sandwiched so as to be in contact with at least a part of the negative electrode layer 15. include. The shape and size of the negative electrode current collector 5 can be appropriately determined by those skilled in the art.

The negative electrode layer 15 is preferably made of metallic lithium. The negative electrode layer 15 may be an alloy containing lithium as a main component or a compound containing lithium as a main component instead of metallic lithium. The lithium-based alloy can include sodium, potassium, magnesium, calcium, aluminum, silicon, germanium, tin, lead, antimony, bismuth, silver, gold, zinc, indium, and the like. A compound containing lithium as a main component is Li _3-x M _x N (M = Co, Cu, Ni).

The buffer layer 17 is a separator sheet containing a lithium ion conductive polymer electrolyte or an organic electrolyte (also referred to as an organic electrolyte). The buffer layer 17 preferably has a lithium ion conductivity (also referred to as lithium ion conductivity) of 10 ⁻⁵ S / cm or more.

  When the negative electrode layer 15 and the isolation layer 12 come into contact with each other, lithium in the negative electrode layer 15 and glass ceramics in the isolation layer 12 may react. For example, when the material of the isolation layer 12 is LTAP, there is a possibility that the LTAP reacts with lithium and deteriorates. However, such a reaction is suppressed by inserting the buffer layer 17 to prevent contact between the negative electrode layer 15 and the isolation layer 12. This contributes to extending the life of the lithium-air battery 1.

  The buffer layer 17 is a solid polymer electrolyte in which a lithium salt is dispersed in a polymer, a separator in which an organic electrolyte in which a lithium salt is dissolved is immersed, and a gel-like material in which a polymer is swollen with an organic electrolyte in which a lithium salt is dissolved. It may be a gel electrolyte which is a polymer electrolyte, or a separator containing the gel electrolyte.

(A) Solid polymer electrolyte serving as a buffer layer The polymer serving as a host is PEO (polyethylene oxide), PPO (polypropylene oxide), or the like. Lithium salts are LiPF ₆ (lithium hexafluorophosphate), LiClO ₄ (lithium perchlorate), LiBF ₄ (lithium tetrafluorophosphate), LiTFSI (Li (CF ₃ SO ₂ ) ₂ N), Li (C ₂ F ₄ SO ₂ ) ₂ N, LiBOB (lithium bisoxalatoborate), and the like.

In addition, when using especially desirable PEO as a solid polymer electrolyte, it is desirable that the molecular weight of PEO is 10 ⁴ to 10 ⁵ , and the molar ratio of PEO and lithium salt is 8 to 30: 1. It is desirable.

In order to improve the strength and electrochemical characteristics of the buffer layer 17, a ceramic filler, for example, BaTiO ₃ powder, may be dispersed in the polymer. The mixing amount of the ceramic filler is desirably 1 to 20 parts by weight with respect to 100 parts by weight of the remaining components.

(B) Separator serving as a buffer layer Further, the buffer layer 17 may be formed by immersing an organic electrolyte in a separator (a sheet made of porous polyethylene, polypropylene, cellulose, or the like). In this case, the organic electrolyte used for the buffer layer 17 is a mixture of ethylene carbonate with diethyl carbonate or dimethyl carbonate, and further LiPF ₆ (lithium hexafluorophosphate), LiClO ₄ (lithium perchlorate), LiBF _4. (Lithium tetrafluorophosphate), LiTFSI (Li (CF ₃ SO ₂ ) ₂ N), Li (C ₂ F ₄ SO ₂ ) ₂ N, LiBOB (lithium bisoxalatoborate) and other lithium salts added It is. By using such a separator, the thickness of the buffer layer 17 can be further reduced with lithium ion conductivity.

(C) Gel electrolyte used as buffer layer Gel electrolyte is a gel-like polymer electrolyte obtained by swelling a polymer with an organic electrolyte in which a lithium salt is dissolved. The polymer serving as the host for the gel electrolyte is PEO (polyethylene oxide), PVA (polyvinyl alcohol), PAN (polyacrylonitrile), PVP (polyvinylpyrrolidone), PEO-PMA (crosslinked product of polyethylene oxide-modified polymethacrylate), PVDF (polyfluoride). And vinylidene fluoride), PVDF-HFP (copolymer of polyvinylidene fluoride and hexafluoropropylene), and the like. The organic electrolyte is, for example, a mixed solvent such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), LiPF ₆ (lithium hexafluorophosphate), LiClO as an electrolyte. ₄ (lithium perchlorate), LiBF ₄ (lithium tetrafluorophosphate), LiTFSI (Li (CF ₃ SO ₂ ) ₂ N), Li (C ₂ F ₄ SO ₂ ) ₂ N, LiBOB (lithium bisoxalatoborate ) And other lithium salts. Mixing of the organic electrolyte solvent can be performed at an arbitrary ratio. The concentration of the lithium salt in the organic electrolyte is preferably 1 to 1.3 (mol / L). The ratio of the polymer in the gel electrolyte is preferably in the range of 3 to 7% by mass in the gel electrolyte. By setting the ratio of the polymer in this range, it is possible to satisfy the desired ion conductivity and the optimum viscosity for production of the negative electrode composite. The thickness of the gel electrolyte is 10 to 100 μm, preferably 50 μm or less. Moreover, the gel electrolysis mass used as a buffer layer has the desirable filling amount which can improve adhesiveness without excess and deficiency with respect to all the opposing surfaces between the negative electrode layer 15 and the isolation layer 12. FIG. By using a gel electrolyte, it becomes easier to prevent air bubbles from entering than when a separator sheet is used. In addition, the gel electrolyte can reduce the thickness of the buffer layer 17 and can simplify the structure by reducing the number of components.

  In lithium ion batteries, it is conventionally known that ion conductivity is better when a polymer electrolyte such as a gel electrolyte is not present between the members. However, when the gel electrolyte is used as the buffer layer 17, the present inventors use cellulose. It has been found for the first time that a lithium-air battery having a higher discharge voltage and stable for a long period of time can be obtained than when a separator impregnated with an organic electrolyte is used. Although the theoretical reason why the battery characteristics are improved by the use of the gel electrolyte is not clear, the gel electrolyte follows the irregularities on the surfaces of the negative electrode layer 15 and the isolation layer 12, and between the negative electrode layer 15 and the isolation layer 12. Therefore, it is presumed that the discharge voltage can be improved. In a lithium-air battery, since lithium ions dissolve from the negative electrode layer 15 during discharge, the volume of the negative electrode layer 15 may decrease. However, the gel electrolyte also follows the decrease in the volume of the negative electrode layer 15. The contact between the negative electrode layer 15 and the isolation layer 12 is maintained. Therefore, it is presumed that it is possible to suppress an increase in internal resistance due to a decrease in adhesion between the negative electrode layer 15 and the isolation layer 12 and maintain the discharge voltage for a long time.

  Furthermore, since the gel electrolyte is in a gel form, when the negative electrode layer 15 and the isolation layer 12 are combined to assemble the negative electrode composite, the gel electrolyte can be easily combined and has excellent workability. Gel electrolytes are excellent in workability in that they are difficult to leak during the production of negative electrode composites and cells, and have the advantage of less variation in cell-to-cell performance because leaks from cell gaps are less likely to occur after production. . In addition, the gel electrolyte has a high viscosity, the contact of the organic electrolyte with the gasket and the outer peripheral sealing member is suppressed, and the deterioration of the adhesive and the resin used as the gasket and the outer peripheral sealing member can be alleviated. As a result, there is an effect that the hermeticity of the negative electrode composite and the cell can be ensured in the long term. Further, there is an advantage that the degree of freedom in selecting the gasket material and the outer peripheral sealing member is improved.

Further, the gel electrolyte is preferably one in which a powder that does not dissolve in the organic electrolyte is dispersed. By dispersing the powder that does not dissolve in the organic electrolyte in the gel electrolyte, there is an effect of preventing the isolation layer 12 and the negative electrode layer 15 from coming into direct contact. The powder to be dispersed in the gel electrolyte may be a fine powder that does not dissolve in the organic electrolyte, preferably does not cause a reaction or deterioration with the members inside the negative electrode composite, and is preferably a fine powder of resin. The resin powder is not particularly limited as long as it does not dissolve in the organic electrolyte, but is preferably one or a combination of two or more resin powders such as polypropylene (PP) and polyethylene (PE). The powder dispersed in the gel electrolyte may be a ceramic filler. The particle size of the powder is preferably an ultrafine powder having a particle size of more than 1 μm and less than about 50 μm and an average particle size of about 5 μm. When the average particle diameter of the powder is within this range, there is an effect that the influence on the battery performance can be reduced. Here, the average particle diameter is a value measured by a laser diffraction / scattering particle size distribution measuring apparatus. The amount of the powder dispersed in the gel electrolyte is preferably 0.5 to 5% by mass in the gel electrolyte, and more preferably 0.5 to 1.5% by mass. By setting the amount of powder dispersion in this range, there is an effect that the influence on the battery performance can be reduced. Moreover, the influence with respect to the viscosity of a gel electrolyte decreases by making the dispersion amount of a powder into 1 mass% or less.
In order to improve the strength and electrochemical characteristics of the gel electrolyte, a ceramic filler, for example, BaTiO ₃ powder, may be further dispersed in the gel electrolyte. The mixing amount of the ceramic filler is desirably 1 to 20 parts by weight with respect to 100 parts by weight of the remaining components.

(D) Gel electrolyte-containing separator serving as a buffer layer The gel electrolyte-containing separator is obtained by impregnating or holding the above-mentioned gel electrolyte in a separator for lithium ion batteries (sheets of porous polyethylene, polypropylene, cellulose, etc.). is there. In the gel electrolyte separator, the weight ratio of the gel electrolyte to the separator is preferably 7 to 30: 1. Although the separator containing a gel electrolyte may use only one sheet, it can also be used in piles. The preferred number of gel electrolyte-containing separators is 1 to 4, although it depends on the material and thickness of the separator. The separator containing the gel electrolyte can improve the discharge voltage and maintain the discharge voltage for a long period of time, like the gel electrolyte of (c) above. This is considered to reduce the contact resistance by maintaining the contact between the negative electrode layer 15 and the isolation layer 12 even when the volume of the negative electrode layer 15 is reduced. Furthermore, by including a gel electrolyte in the separator, the workability when inserting the buffer layer 17 in the production of the negative electrode composite is improved, the reproducibility of the electrochemical characteristics of the cell is increased, and the yield during production is increased. Improve. In addition, the use of the gel electrolyte-containing separator suppresses contact of the organic electrolyte with the gasket and the outer peripheral sealing member. For this reason, deterioration of the adhesive, resin, etc. used as the gasket and the outer peripheral sealing member can be alleviated, and the sealability of the negative electrode composite and the cell can be ensured for a long time.

  Here, the buffer layer 17 is not necessarily provided in the negative electrode composite 8, and is an arbitrary component. In other words, in the negative electrode composite 8, the negative electrode layer 15 may be disposed so as to be directly adjacent to the isolation layer 12 without separating the buffer layer 17.

  The isolation layer 12 bears most of the outer shell of the negative electrode composite 8 and protects the negative electrode layer 15 from moisture. That is, the two isolation layers 12 face the air electrode layers 13 of the different air electrodes 9.

The isolation layer 12 has a rectangular flat plate shape that is slightly larger than the negative electrode layer 15, and sandwiches the entire two negative electrode layers 15 to be integrated. That is, the central portion of the isolation layer 12 faces the negative electrode layer 15, and the outer peripheral edge of the isolation layer 12 projects outward from the negative electrode layer 15 like a ridge or eaves.

The isolation layer 12 is a glass ceramic having water resistance and lithium ion conductivity. The isolation layer 12 preferably has a lithium ion conductivity of 10 ⁻⁵ S / cm or more. Examples of the isolation layer 12 include a NASICON (Na Superconducting Conductor) type lithium ion conductor. Further, as the isolation layer 12, a part of the tetravalent cation M of the lithium ion conductor represented by the general formula LiM ₂ (PO ₄ ) ₃ (M is a tetravalent cation such as Zr, Ti, Ge) is In, A lithium ion conductor represented by the general formula Li _{1 + x} M _2−x M ′ _x (PO ₄ ) _{3 in} which lithium ion conductivity is improved by substitution with a trivalent cation M ′ such as Al can be given. Further, as the isolation layer 12, a part of the tetravalent cation M of the lithium ion conductor represented by the general formula LiM ₂ (PO ₄ ) ₃ (M is a tetravalent cation such as Zr, Ti, Ge, etc.) is Ta, etc. lithium ion conductor represented by "formula _{Li 1-x M 2-x} M with improved lithium ion conductivity by replacing" x _{(PO 4) 3} may be mentioned pentavalent cation M. P in these lithium ion conductors may be substituted with Si, and the lithium ion conductor represented by the general formula Li _{1 + x + y} Ti _2−x Al _x P _3−y Si _y O ₁₂ (LTAP) Desirable from the viewpoint of sex.

  The joint portion 16 is bridged between the outer peripheral edge portions of the two isolation layers 12. The joint portion 16 closes a region sandwiched between the two isolation layers 12, cooperates with the two isolation layers 12, a part of the negative electrode current collector 5, two negative electrode layers 15, and a buffer layer 17 in this region. Enclose.

  The joint 16 was filled with an adhesive such as an epoxy resin adhesive, a silicone adhesive, or a styrene-butadiene rubber adhesive between the outer peripheral edges of the two isolation layers 12 and cured. Is. Since the junction 16 is exposed to both the buffer layer 17 and the electrolyte 7, it is preferable to have organic electrolyte resistance and alkali resistance. In the case where a polymer electrolyte is used for the buffer layer 17, it is sufficient that the bonding portion 16 has alkali resistance.

  Note that the bonding portion 16 may be one that is filled with resin instead of the adhesive and cured.

  The lithium-air battery 1 and the negative electrode composite 8 according to this embodiment cause both surfaces of the plate-shaped negative electrode composite 8 to contribute to power generation. By making the negative electrode composite 8 double-sided, it is possible to improve the input / output density by doubling the effective area for the battery reaction per volume compared to the conventional lithium-air battery.

  Further, the lithium-air battery 1 and the negative electrode composite 8 according to this embodiment eliminate the need for a laminate film in a conventional lithium-air battery, reduce the number of parts, and are difficult in joining the laminate film polypropylene and glass ceramics. No need for adhesion. Further, the negative electrode composite 8 and the air electrode 9 are easily stacked as one air battery cell 11.

  Compared to a conventional lithium air battery in which an aqueous electrolyte is included in each unit cell in which a negative electrode composite and an air electrode are paired, the lithium air battery 1 and the negative electrode composite 8 according to the present embodiment include a plurality of air. Battery cells 11 are connected in parallel and accommodated in one case 2. With such a structure, the lithium air battery 1 and the negative electrode composite 8 according to the present embodiment do not require a partition for each air battery cell 11 (corresponding to the exterior of a conventional lithium air battery), and a plurality of air The battery 7 can share the electrolyte 7, and the lithium-air battery 1 as a whole can optimize the storage amount of the electrolyte 7 to reduce the weight and volume.

  Furthermore, when the lithium-air battery 1 and the negative electrode composite 8 according to the present embodiment store the aqueous electrolyte as the electrolyte 7 in the case 2, even if the electrolyte 7 volatilizes as the discharge progresses, the air is successively introduced. The electrolyte 7 can be supplied to the pole 9. As a result, the lithium-air battery 1 and the negative electrode composite 8 according to the present embodiment do not require replenishment of the electrolyte 7 over a long period of time, and prevent performance degradation due to shortage of the electrolyte 7.

  Furthermore, since the lithium-air battery 1 and the negative electrode composite 8 according to the present embodiment join the two isolation layers 12 at the joint 16, compared with difficult adhesion in joining the laminate film polypropylene and glass ceramics. And can be manufactured easily.

  Therefore, according to the lithium air battery 1 and the negative electrode composite 8 according to the present embodiment, even if the energy density and the input / output density are increased as compared with the conventional air battery, it can be made compact by suppressing an extreme increase in size. .

  FIG. 7 is a schematic cross-sectional view showing another example of the negative electrode composite body of the lithium-air battery according to the embodiment of the present invention.

  As shown in FIG. 7, the negative electrode composite 8A includes a negative electrode current collector 5, two negative electrode layers 15, two isolation layers 12, a buffer layer 17, a gasket 18, and an outer peripheral sealing member 19. Prepare. Components having the same reference numerals have the same configurations as those in the embodiment described with reference to FIGS. 5 and 6, and redundant descriptions are omitted. The negative electrode composite 8A can be used in place of the negative electrode composite 8 in the lithium-air batteries 1 and 1A.

  In the present embodiment, the gasket 18 is disposed between the two isolation layers 12 so as to surround the outer periphery of the negative electrode layer 15, and the negative electrode layer 15 is disposed in the frame of the gasket 18. The gasket 18 may be fixed to the inner surface of each of the isolation layers 12 by any method, but is preferably fixed by the adsorptivity and / or adhesiveness of the gasket 18 itself. The gasket 18 may be in contact with the outer periphery of the negative electrode layer 15 or may be separated from the outer periphery. The gasket 18 consists of two gaskets and is overlaid after being placed on the inner surface of each of the two isolation layers 12. The overlapping surfaces 20 of the two gaskets are preferably in close contact with each other due to the adsorptivity and / or adhesiveness of the gasket itself, and the space in the gasket 18 is sealed. The negative electrode current collector 5 is led out of the negative electrode composite 8 </ b> A through the overlapping surface 20. Alternatively, the gasket 18 may be configured as one member. In such a case, a through hole for the negative electrode current collector 5 is provided in the gasket 18.

  The gasket 18 is not particularly limited as long as it is a rubber or elastomer resistant to an organic electrolyte, but a rubber or elastomer made of ethylene-propylene-diene copolymer, or a fluorine-based rubber or elastomer is suitable. Examples of the rubber made of ethylene-propylene-diene copolymer include EPM, EPDM, and EPT. Examples of the fluorine-based rubber or elastomer include vinylidene fluoride (FKM), tetrafluoroethylene-propylene (FEPM), tetrafluoroethylene-purple fluorovinyl ether (FFKM), and the like. The physical property of the rubber or elastomer is preferably a soft hardness. The hardness of the gasket material is preferably around Shore A 50-70. If the gasket material is extremely soft, there may be problems such as poor processability. Since the gasket 18 has soft hardness and rubber elasticity, it is possible to adjust the height of the constituent members inside the negative electrode composite 8A. That is, by pressing one or both of the isolation layers 12 directly or indirectly, the overall adhesion of the contact surface between the buffer layer 17 and the isolation layer 12 can be improved. Furthermore, this makes it possible to improve the contact between the isolation layer 12 and the negative electrode layer 15 via the buffer layer 17. Further, the rubber or elastomer is preferably a type in which the raw material before molding is liquid and has high adsorptivity and / or adhesiveness.

  The gasket 18 preferably has a rectangular window frame shape. The size of the gasket 18 has an inner dimension in which the negative electrode layer 15 can be disposed in the frame, and is an outer dimension that is almost the same size as the isolation layer 12. The thickness of the gasket 18 may be approximately the same as the total thickness of the components laminated between the isolation layers 12.

  The outer peripheral sealing member 19 is disposed at the outer peripheral ends of the two isolation layers 12 and hermetically seals the two isolation layers while exposing the remaining part of the negative electrode current collector to the outside of the two isolation layers. The outer peripheral sealing member 19 is disposed on the entire periphery of the outer peripheral edge of the two isolation layers 12 so as to cover the gap between the two isolation layers. The outer peripheral sealing member 19 preferably contacts the gasket 18 and fixes the isolation layer 12 and the gasket 18 from the outside. The outer periphery sealing member 19 can further improve the sealing performance of the negative electrode composite 8A. The outer peripheral sealing member 19 is not particularly limited as long as it can be hermetically sealed between two isolation layers and can shrink in the thickness direction of the negative electrode composite 8A, but is preferably an adhesive. Adhesives with low moisture permeability and high sealing properties are suitable, for example, epoxy adhesives, acrylic adhesives, silicone adhesives, olefin adhesives, and synthetic rubber adhesives. Can be mentioned. More preferably, the adhesive further has resistance to an aqueous electrolyte (preferably an organic electrolyte), and examples thereof include an epoxy adhesive and an olefin adhesive. The adhesive preferably has curing conditions that cure in a short time at room temperature. In addition, the adhesive used as the outer peripheral sealing member 19 may contain a trace amount component such as an alcohol-based solvent that deteriorates metallic lithium, but since the space between the isolation layers is sealed by the gasket 18, Such an alcohol solvent can be prevented from entering the negative electrode composite 8A. As a result, the degree of freedom of the type of adhesive that can be used for the external sealing member 19 can be improved. The adhesive has a penetrating portion through which the negative electrode current collector 5 penetrates.

  Alternatively, the outer peripheral sealing member 19 may be a member that is fixed by pressing and sandwiching the outer surface of each of the two isolation layers 12 in the vicinity of the outer peripheral end, such as a clip. When the outer peripheral sealing member 19 is such a member, when the thickness of the negative electrode layer 15 is reduced due to discharge during use, without performing an operation of pressing one or both of the isolation layers 12, The distance between the negative electrode layer 15 and the isolation layer 12 is automatically contracted to maintain the adhesion between the buffer layer 17 and the isolation layer 12 and the adhesion between the negative electrode layer 15 and the isolation layer 12 via the buffer layer 17. be able to. Further, the sealing property between the two isolation layers by the gasket 18 can be enhanced. A member such as a clip as the external sealing member 19 can be used in combination with the above adhesive.

 The negative electrode composite 8A according to the present embodiment can increase the adhesion between the isolation layer 12 and the negative electrode layer 15 via the buffer layer 17 by pressing one or both of the isolation layers 12, and as a result, The internal resistance can be reduced and the discharge voltage can be increased. Due to the discharge during use of the lithium-air battery, the thickness of the negative electrode layer 15 is reduced, and the adhesion between the buffer layer 17 and the isolation layer 12 and the adhesion between the negative electrode layer 15 and the isolation layer 12 through the buffer layer 17 are reduced. Even in the case where the property is deteriorated, the distance between the negative electrode layer 15 and the isolation layer 12 can be shortened by directly or indirectly pressing one or both of the isolation layers 12 again. Can be secured. That is, even if the adhesion between the isolation layer 12 and the buffer layer 17 and the isolation layer 12 and the negative electrode layer 15 through the buffer layer 17 is reduced due to the discharge, the negative electrode complex is not decomposed and is simply pressed. A reduction in internal resistance, that is, an increase in discharge voltage can be achieved only by work.

  Furthermore, in the negative electrode composite 8A according to the present embodiment, the gaskets 18 and the gasket 18 and the isolation layer 12 are fixed by the adsorption and / or adhesion of the gasket 18, and therefore the space in the negative electrode composite 8A is sealed. High nature. Further, by providing the outer peripheral sealing member 19, the sealing performance can be further enhanced. For this reason, the penetration | invasion of the water | moisture content and solution into the negative electrode composite 8A can be prevented.

  Furthermore, in the negative electrode composite body 8A according to the present embodiment, the gaskets 18 or the gasket 18 and the isolation layer 12 are fixed by the adsorption and / or adhesion of the gasket 18, so that an adhesive is used as the outer peripheral sealing member 19. When applying, there is no problem that lateral displacement between the gaskets 18 or between the isolation layer 12 and the gasket 18 occurs. Therefore, there is an effect that workability in the manufacturing process of the negative electrode composite 8A is improved.

  Further, in the negative electrode composite 8A according to this embodiment, since the gasket 18 is resistant to an organic electrolyte, the gasket 18 is deteriorated even when an organic electrolyte that causes deterioration of an adhesive, a resin, or the like is used in the negative electrode composite. Therefore, the hermeticity inside the negative electrode composite 8A can be maintained.

  FIG. 8 is a schematic cross-sectional view showing another example of the negative electrode composite body of the lithium-air battery according to the embodiment of the present invention.

  As shown in FIG. 8, in the negative electrode composite 8B, the area ratio of the negative electrode layer 15 to the isolation layer 12 is higher than that of the negative electrode composite 8A, and a part of the gasket 18 protrudes outside the end of the isolation layer 12. ing. The outer peripheral sealing member 19 is disposed on the outer peripheral edge of the isolation layer 12 while covering the gasket 18 over the entire outer periphery of the two isolation layers 12. Components having the same reference numerals have the same configuration as the embodiment described with reference to FIGS. 5 to 7, and redundant description is omitted. Negative electrode composite 8B can be used in place of negative electrode composite 8 in lithium-air batteries 1 and 1A.

  Since the negative electrode composite 8B according to this embodiment has a high area ratio of the negative electrode layer 15 to the isolation layer 12, the battery capacity can be increased while maintaining the size of the negative electrode composite 8B compact.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, the lithium air battery and negative electrode composite_body | complex which concern on this invention are not restrict | limited by the following Example.

[Example 1]
(Preparation of negative electrode composite)
The negative electrode composite 108 was produced by the following procedure. FIG. 9 shows the disassembled state and assembled state of the negative electrode composite.
(1) Solid electrolyte 112 (lithium ion conductive glass ceramics (LTAP) thin plate, square, two pieces), which is a constituent member of the negative electrode composite 108, metal lithium 115 (square, two pieces, one piece of copper foil (negative electrode collection) Electrical body) 105 (attached to both sides of a rectangular plate-shaped portion and a belt-shaped terminal portion)), cellulose separator 117 (square, two sheets), and gasket sheet 118 (EPDM, square frame, two sheets) are prepared. did. A gasket sheet 118 was attached to each of the two solid electrolytes 112.
(2) On one solid electrolyte 112 shown on the lower side in FIG. 9, a cellulose separator 117 is disposed so as to enter the frame of the gasket sheet 118, and an organic electrolyte (EC: EMC = 1: 1, 1M). Of LiPF ₆ ) was dropped into the cellulose separator 117 and soaked throughout. The metallic lithium 115 was placed on the cellulose separator 117 so as to enter the frame of the gasket sheet 118, and the second cellulose separator 117 was placed on the metallic lithium 115. An organic electrolyte was dropped onto the second cellulose separator 117 and soaked throughout.
(3) The upper solid electrolyte 112 produced in (1) is placed over the product obtained in (2), and the upper and lower gasket sheets 118 are pasted so as not to shift so that no external air or the like enters. Thus, the gasket sheet 118 was sealed by the adhesiveness. The components inside the negative electrode composite 208 were fixed by pressing the whole from the outside so that the solid electrolyte 112 and the metal lithium 115 were particularly in good contact with each other.
(4) An epoxy adhesive 119 (two-component room temperature curing type) is thinly applied to the entire periphery of the outer peripheral edge of the solid electrolyte 112 so that the space between the two solid electrolytes 112 is sealed. 119 was cured.

(Production of air electrode)
N-methyl-2-pyrrolidone (NMP) was measured by measuring 80 mg of platinum-supported carbon (Pt 45.8%) as a catalyst for oxygen reduction of the positive electrode and 20 mg of polyvinylidene fluoride (PVdF) as a binder (binder). 3 ml was added to prepare a mixed solvent.
Stir and disperse the mixed solvent for 15 minutes with an agitator (AR-100 manufactured by Shinki Co., Ltd.) and 60 minutes with ultrasonic waves, and apply on the carbon cloth using a coating machine (K202 Control Coater made by Matsuo Sangyo). Then, it was placed on a hot plate and dried by heating at 110 ° C. for 1 hour to produce an air electrode having a platinum loading of 0.25 mg / cm ² . As a current collector for the air electrode, the carbon cloth of the air electrode was extended in a rectangular shape.

(Preparation of aqueous electrolyte)
4.24 g of LiCl was dissolved in 50 ml of purified water to prepare a 2M LiCl aqueous solution. In order to hold the aqueous electrolyte, the aqueous electrolyte was dropped onto the cellulose sheet and placed between the air electrode and the negative electrode.

(Production of cell)
In a plastic case with a hole and a size that can accommodate the negative electrode composite, the air electrode, the cellulose sheet with the aqueous electrolyte dropped, the negative electrode composite, the cellulose sheet with the aqueous electrolyte dropped, and the air electrode in this order The stacked ones were stored so that there was no displacement, and a lithium-air battery cell was obtained.

[Comparative Example 1]
(Preparation of negative electrode composite)
A negative electrode composite 208 was produced by the following procedure. Aluminum laminate packaging material 202 (PP resin / aluminum / PET resin, square frame) for window material on one surface of solid electrolyte 212 (lithium ion conductive glass ceramics (LTAP) thin plate, square, 1 sheet) Synthetic rubber adhesive Glued with. On the other surface of the solid electrolyte 212, a cellulose separator 217 (square, one sheet) was disposed, and an organic electrolyte (EC: EMC = 1: 1, 1M LiPF ₆ ) was impregnated. Next, metallic lithium 215 attached to one surface of the negative electrode current collector (copper foil) 205 was placed on the cellulose separator 217. In order to wrap these members between the aluminum laminate packaging material 202 for window material and the aluminum laminate packaging material 202 for outside (PP resin / aluminum / PET resin, square) to form a bag-like cell, The ends of the four sides of the aluminum laminate packaging material 202 for the outside and the window material were heat-welded and sealed. The amount of metallic lithium used was almost the same as in Example 1.

(Production of air electrode)
The air electrode 209 was produced in the same manner as in Example 1. An aluminum foil was used as the air electrode current collector 206.

(Preparation of aqueous electrolyte)
The aqueous electrolyte was prepared in the same manner as in Example 1.

(Production of cell)
The structure of the cell of Comparative Example 1 is shown in FIG. A cell of the lithium-air battery 201 was formed by stacking the cellulose sheet 219 on which the aqueous electrolyte was dropped onto the negative electrode composite 208 of Comparative Example 1 and the air electrode 209 so that there was no deviation in this order.

[Discharge test 1]
In the cells of Example 1 and Comparative Example 1, the discharge voltage when discharged at 4 mA / cm ² (discharge rate of about 0.1 C) was measured with a BAS electrochemical analyzer ALS608A over 6 hours. Here, 1C refers to a current value at which discharge of a cell having a nominal capacity is constant current and the discharge is completed in exactly one hour. The measurement result of the discharge voltage is shown in FIG. As shown in FIG. 11, the cell of Example 1 showed a higher discharge voltage than the cell of Comparative Example 1 at all measurement times. The average discharge voltage of the cell of Example 1 was 1.56 V, the cell of Comparative Example 1 was 0.65 V, and the cell of Example 1 was twice or more.

[Impedance evaluation]
The impedance in the range of 1 MHz to 10 mHz of the cell of Example 1 and the cell of Comparative Example 1 was measured using a Frequency Response Analyzer (FRA) 1255B manufactured by Solartron. FIG. 12 shows the measurement result (Nyquist plot). Z ′ represents a real part, and Z ′ ′ represents an imaginary part. From the Nyquist plot shown in FIG. 12, it was found that the cell of Example 1 showed a remarkably low value of about half the impedance of the cell of Comparative Example 1. Thereby, since the cell of Example 1 and the cell of Comparative Example 1 use the air electrode produced on the same conditions, the low impedance of the cell of Example 1 is low in internal resistance in a negative electrode composite. This is thought to be due to the above. Moreover, in the cell of Example 1, it is considered that the discharge voltage shown in FIG. 11 showed a high value due to the low internal resistance of the negative electrode composite.

[Example 2]
(Preparation of negative electrode composite)
The negative electrode composite of Example 2 was prepared by the following procedure in an argon gas atmosphere having an oxygen concentration of 1 ppm or less and a dew point of -76 ° C. dp. The negative electrode composite was assembled in the same manner as the structure shown in FIG. 9 for the negative electrode composite of the cell of Example 1.
(1) Solid electrolyte (lithium ion conductive glass ceramics (LTAP) thin plate, square, two pieces), metallic lithium (square, two pieces, one piece of copper foil (square plate-like part) which are constituent members of the negative electrode composite And a strip-shaped terminal portion), a cellulose separator (square, 2 sheets), and a gasket sheet (EPDM, square frame, 2 sheets) were prepared. A gasket sheet was attached to each of the two solid electrolytes.
(2) PEO was added to an organic electrolyte (EC: EMC = 1: 1, 1M LiPF ₆ ) to form a gel, and a PEO gel electrolyte having a concentration of 5% by mass was prepared. Next, a cellulose separator was immersed in the gel electrolyte. The cellulose separator impregnated with the gel electrolyte was placed on one solid electrolyte so as to enter the frame of the gasket sheet. The metallic lithium was placed on the cellulose separator so as to enter the frame of the gasket sheet, and the second cellulose separator impregnated with the gel polymer by the same method was placed on the metallic lithium.
(3) Cover the solid electrolyte prepared in (1) from the top of the product in (2) and paste the upper and lower gasket sheets so that they do not deviate from each other. It was sealed by the adhesiveness of. The members inside the negative electrode composite were pressed and fixed from the outside so that the solid electrolyte and lithium metal were in good contact with each other.
(4) Apply an epoxy adhesive (two-component room temperature curing type) thinly on the entire periphery of the outer edge of the solid electrolyte so as to seal between the two solid electrolytes, and cure the epoxy adhesive. It was.

(Production of air electrode)
N-methyl-2-pyrrolidone (NMP) was measured by measuring 80 mg of platinum-supported carbon (Pt 45.8%) as a catalyst for oxygen reduction of the positive electrode and 20 mg of polyvinylidene fluoride (PVdF) as a binder (binder). 3 ml was added to prepare a mixed solvent.
The mixed solvent was stirred and dispersed for 15 minutes with a stirrer (AR-100 manufactured by Shinki Co., Ltd.) and 60 minutes with ultrasonic waves, and two metallic lithiums were combined using a coating machine (K202 control coater manufactured by Matsuo Sangyo Co., Ltd.). It apply | coated on the carbon cloth of the same size as a thing, Then, it put on the hotplate and heat-dried at 110 degreeC for 1 hour, and produced the air electrode of platinum carrying amount 0.5mg / cm < ² >. As a current collector for the air electrode, the carbon cloth of the air electrode was extended in a rectangular shape.

(Preparation of aqueous electrolyte)
4.24 g of LiCl was dissolved in 50 ml of purified water to prepare a 2M LiCl aqueous solution. In order to hold the aqueous electrolyte, the aqueous electrolyte was dropped onto the cellulose sheet and placed between the air electrode and the negative electrode.

(Production of cell)
An air electrode, a cellulose sheet in which an aqueous electrolyte is dropped, a negative electrode composite, a cellulose sheet in which about 500 μl of an aqueous electrolyte is dropped, and an air electrode in a plastic case with a hole and a size that can accommodate the negative electrode composite Were stacked so that there was no deviation in this order, and the cell of the lithium-air battery of Example 2 was obtained.

[Example 3]
(Preparation of negative electrode composite)
The negative electrode composite of the cell of Example 3 was produced by the following procedure. The negative electrode composite was assembled in the same manner as the structure shown in FIG. 9 for the negative electrode composite of the cell of Example 1. In the cell of Example 3, components having the same material and size as those of the cell of Example 2 were used except that a cellulose separator impregnated with an organic electrolyte was used as a buffer layer instead of a cellulose separator impregnated with a gel electrolyte. .
(1) Solid electrolyte (lithium ion conductive glass ceramics (LTAP) thin plate, square, two pieces), metal Li (square, two pieces, one piece of copper foil (rectangular plate-like portion) which are constituent members of the negative electrode composite And a strip-shaped terminal portion), a cellulose separator (square, 2 sheets), and a gasket sheet (EPDM, square frame, 2 sheets) were prepared. A gasket sheet was attached to each of the two solid electrolytes.
(2) A cellulose separator is disposed on one solid electrolyte so as to enter the frame of the gasket sheet, and an organic electrolyte (EC: EMC = 1: 1, 1M LiPF ₆ ) is dropped onto the cellulose separator. Soaked in the whole. Metal Li was placed on the cellulose separator so as to enter the frame of the gasket sheet, and a second cellulose separator was placed on the metal Li. The organic electrolyte was dropped into the second cellulose separator and soaked throughout.
(3) The solid electrolyte prepared in (1) is placed on the product of (2), and the gasket sheets attached to each of the two solid electrolytes are pasted so as not to deviate from each other. It was sealed by the adhesiveness of the gasket sheet so as not to enter. The constituent members inside the negative electrode composite were pressed and fixed from the outside so that the solid electrolyte and the metal Li were particularly in good contact with each other.
(4) Apply an epoxy adhesive (two-component room temperature curing type) thinly on the entire periphery of the outer edge of the solid electrolyte so as to seal between the two solid electrolytes, and cure the epoxy adhesive. It was.

  The production of the air electrode, the preparation of the aqueous electrolyte, and the production of the cell were carried out in the same manner as in Example 2.

[Discharge test 2]
In the cells of Example 2 and Example 3, the discharge voltage when discharged at 4 mA / cm ² (discharge rate of about 0.1 C) was measured over 7 hours with an electrochemical analyzer ALS608A manufactured by BAS. Here, 1C refers to a current value at which discharge of a cell having a nominal capacity is constant current and the discharge is completed in exactly one hour. The measurement results of the discharge voltage are shown in FIG. As shown in FIG. 13 and Table 1, both the cell of Example 2 and the cell of Example 3 exhibited a high discharge voltage during all measurement times. The average discharge voltage was 1.89 V for the cell of Example 2, 1.33 V for the cell of Example 3, and the discharge voltage of the cell of Example 2 was significantly improved as compared to the cell of Example 3.

[Example 4]
(Preparation of negative electrode composite)
The negative electrode composite of the cell of Example 4 was prepared by the following procedure under an argon gas atmosphere having an oxygen concentration of 1 ppm or less and a dew point of -76 ° C. dp. The negative electrode composite was assembled in the same manner as the structure shown in FIG. 9 for the negative electrode composite of the cell of Example 1. In the cell of Example 4, constituent members having the same material and size as those of the cell of Example 2 were used except that a gel electrolyte containing powder was used as a buffer layer instead of the cellulose separator impregnated with the gel electrolyte.
(1) Solid electrolyte (lithium ion conductive glass ceramics (LTAP) thin plate, square, two pieces), metallic lithium (square, two pieces, one piece of copper foil (square plate-like part) which are constituent members of the negative electrode composite And a gasket sheet (EPDM, square frame, 2 sheets) were prepared. A gasket sheet was attached to each of the two solid electrolytes.
(2) PEO is added to an organic electrolyte (organic electrolyte solution: EC: EMC = 1: 1, 1M LiPF ₆ ) to form a gel, 5% by mass of PEO, and a fine powder of polypropylene having an average particle size of 5 μm A powder electrolyte was added to prepare a gel electrolyte of PEO at a concentration of 4% by mass containing 1% by mass of polypropylene fine powder. The gel electrolyte containing the fine powder powder of polypropylene was placed on one solid electrolyte so as to enter the frame of the gasket sheet, and adjusted with a spatula or the like so that the surface was uniform. Metal lithium was placed thereon, placed so as to be within the frame of the gasket sheet, and a gel electrolyte containing a fine powder of polypropylene was placed on the metal lithium so as to have a uniform surface.
(3) Cover the solid electrolyte prepared in (1) from the top of the product in (2) and paste the upper and lower gasket sheets so that they do not deviate from each other. It was sealed by the adhesiveness of. The constituent members inside the negative electrode composite were fixed by pressing the whole from the outside so that the solid electrolyte and the metal lithium were particularly in good contact with each other through the gel electrolyte.
(4) Apply an epoxy adhesive (two-component room temperature curing type) thinly on the entire periphery of the outer edge of the solid electrolyte so as to seal between the two solid electrolytes, and cure the epoxy adhesive. It was.

(Production of air electrode)
N-methyl-2-pyrrolidone (NMP) was measured by measuring 80 mg of platinum-supported carbon (Pt 45.8%) as a catalyst for oxygen reduction of the positive electrode and 20 mg of polyvinylidene fluoride (PVdF) as a binder (binder). 3 ml was added to prepare a mixed solvent.
The mixed solvent was stirred and dispersed for 15 minutes with a stirrer (AR-100 manufactured by Shinki Co., Ltd.) and 60 minutes with ultrasonic waves, and two metallic lithiums were combined using a coating machine (K202 control coater manufactured by Matsuo Sangyo Co., Ltd.). It apply | coated on the carbon cloth of the same size as a thing, Then, it put on the hotplate and heat-dried at 110 degreeC for 1 hour, and produced the air electrode of platinum carrying amount 0.5mg / cm < ² >. As a current collector for the air electrode, the carbon cloth of the air electrode was extended in a rectangular shape.

(Preparation of aqueous electrolyte)
4.24 g of LiCl was dissolved in 50 ml of purified water to prepare a 2M LiCl aqueous solution. In order to hold the aqueous electrolyte, the aqueous electrolyte was dropped onto the cellulose sheet and placed between the air electrode and the negative electrode.
The cell was manufactured in the same manner as in Example 2.

[Discharge test 3]
The discharge voltage of the cell of Example 4 was measured under the same conditions as in discharge test 2. The results are shown in Table 2. The cell of Example 4 showed high initial discharge voltage and average discharge voltage.

DESCRIPTION OF SYMBOLS 1, 1A Lithium air battery 2 Case 5 Negative electrode current collector 6, 6A Air electrode current collector 7 Electrolyte 8, 8A, 8B Negative electrode composite 9, 9A Air electrode 11 Air battery cell 12 Isolation layer 13, 13A Air electrode layer 13a Crease 13b Flat portion 15 Negative electrode layer 16 Joint portion 17 Buffer layer 18 Gasket 19 Outer peripheral sealing member 20 Gasket mating surface

105 Copper foil 108 Negative electrode composite 112 Solid electrolyte 115 Metallic lithium 117 Cellulose separator 118 Gasket sheet 119 Epoxy adhesive


201 Lithium-air battery 202 Aluminum laminate packaging material 205 Negative electrode current collector (copper foil)
206 Air electrode current collector 208 Negative electrode composite 209 Air electrode 212 Solid electrolyte 215 Metal lithium 217 Cellulose separator 219 Cellulose sheet

Claims (11)

A plate-like or linear negative electrode current collector;
Two negative electrode layers made of metal lithium, an alloy containing lithium as a main component, or a compound containing lithium as a main component and sandwiching a part of the negative electrode current collector,
Two plate-shaped isolation layers having lithium ion conductivity sandwiching all of the two negative electrode layers;
A negative electrode composite comprising a gasket disposed between the two isolation layers so as to surround the two negative electrode layers and sealing a space between the two isolation layers;
An air electrode layer containing a conductive material and facing at least one of the two isolation layers;
A lithium-air battery comprising: an air electrode comprising a plate-like or linear air electrode current collector electrically connected to the air electrode layer. A plate-like or linear negative electrode current collector;
Two negative electrode layers made of metal lithium, an alloy containing lithium as a main component, or a compound containing lithium as a main component and sandwiching a part of the negative electrode current collector,
Two plate-shaped isolation layers having lithium ion conductivity sandwiching all of the two negative electrode layers;
A negative electrode composite of a lithium air battery, comprising: a gasket disposed between the two isolation layers so as to surround the two negative electrode layers and sealing a space between the two isolation layers.   The negative electrode composite body of a lithium air battery according to claim 2, further comprising an outer peripheral sealing member that hermetically seals the two isolation layers on an outer peripheral portion of the two isolation layers.   The negative electrode composite according to claim 2 or 3, wherein the gasket is rubber or elastomer.   The negative electrode composite according to claim 4, wherein the rubber or elastomer is a rubber or elastomer made of ethylene-propylene-diene copolymer, or a fluorine-based rubber or elastomer.   The negative electrode composite according to claim 2, further comprising a buffer layer between the negative electrode layer and the isolation layer.   The negative electrode composite according to claim 6, wherein the buffer layer is a gel electrolyte or a separator containing a gel electrolyte.   The negative electrode composite according to claim 7, wherein the gel electrolyte includes a powder that does not dissolve in the organic electrolyte.   The negative electrode composite according to claim 8, wherein the powder is a resin powder.   The negative electrode composite according to claim 9, wherein the resin powder is polypropylene, polyethylene, or a mixture thereof. The negative electrode composite according to any one of claims 2 to 10,
An air electrode layer containing a conductive material and facing at least one of the two isolation layers;
A lithium-air battery comprising: an air electrode comprising a plate-like or linear air electrode current collector electrically connected to the air electrode layer.

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