CN104659443B - Lithium-air battery and negative electrode complex of lithium-air battery - Google Patents

Abstract

The present invention provides a compact lithium-air battery and a lithium-air battery negative electrode assembly capable of suppressing extreme enlargement even if the energy density and input/output density are increased compared with conventional air batteries. The lithium-air battery includes a negative electrode composite and an air electrode. The negative electrode composite includes: a plate-shaped or linear negative electrode collector; two plate-shaped negative electrode layers, which are made of metal lithium, an alloy with lithium as the main component, or Lithium-based compound formation, which sandwiches a part of the negative electrode current collector; two separator layers in the shape of a plate, which sandwich the entirety of the two negative electrode layers, and have lithium ion conductivity; and a spacer , which is arranged between two separator layers and surrounds the two negative electrode layers, and seals the space between the two separator layers; the air electrode includes: an air electrode layer, which contains a conductive material and is connected with the two at least one of the separation layers is opposite; and a plate-shaped or linear air electrode current collector electrically connected to the air electrode layer.

Description

Lithium-air battery and negative electrode complex of lithium-air battery

technical field

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

Background technique

Due to the popularity of electric vehicles, hopes are placed on air batteries that have an energy density much greater than that of lithium-ion batteries. Air batteries use oxygen in the air as a positive electrode active material.

In addition, there are known lithium-air batteries in which metallic lithium, an alloy containing lithium as a main component, or a compound containing lithium as a main component is used as a negative electrode active material. Focusing on the types of electrolytes, lithium-air batteries are roughly classified into two types: aqueous electrolytes and nonaqueous electrolytes. Lithium-air batteries with non-aqueous electrolytes have become the mainstream of research and development because they can utilize the technology of lithium-ion batteries in addition to the air electrode.

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

Therefore, there is known a lithium-air battery having a negative electrode complex having a polymer electrolyte buffer layer formed on one side of plate-shaped metal lithium and having lithium ion conductivity (also referred to as lithium ion conductivity, Lithium ion conductivity.) The glass ceramics as a water-resistant layer covers one side of the buffer layer of the polymer electrolyte (for example, refer to Patent Document 1 and Non-Patent Document 1.).

Patent Document 1: Japanese Patent Laid-Open No. 2010-192313

Non-Patent Document 1: Yasuo Takeda, Makoto Imanishi, Osamu Yamamoto, "Current Status and Issues of Aqueous Lithium/Air Batteries", GS Yuasa Technical Report, June 2010, Vol. 7, No. 1, p.1- 6

In the conventional air batteries described in Patent Document 1 and Non-Patent Document 1, one side of an air electrode faces one side of a negative electrode assembly, and the battery is enclosed in a container or a laminated film. To increase the input/output density (output per weight) of these conventional air batteries, simply use a large number of air batteries with the same structure, or simply increase the number of air batteries with the same structure. However, simply using a large number of air batteries of the same structure or simply enlarging the air batteries of the same structure inefficiently and greatly increases the required air battery mounting space. It is practically difficult to adopt.

In addition, in the conventional air battery described in Non-Patent Document 1, the negative electrode assembly is enclosed in a laminated film having a three-layer structure of polypropylene (PP), aluminum foil, and polyethylene terephthalate (PET), which has gas barrier properties. inside the membrane. Furthermore, in the negative electrode assembly of Non-Patent Document 1, in order to ensure lithium ion conductivity inside and outside the laminated film, openings penetrating through the laminated film are sealed with glass ceramics having lithium ion conductivity as a window material.

However, it is difficult to combine polypropylene (PP) of the laminated film with an adhesive and glass ceramics of the negative electrode assembly, and lacks durability. In addition, in order to thermally weld the laminated film to form the negative electrode assembly, a welding margin of about 10 mm is required on the outer peripheral edge of the laminated film, resulting in an increase in the area of the laminated film and an increase in the volume of the air battery.

That is, conventional air batteries disclose small cells for experiments, but it is difficult to construct a compact practical battery with increased battery characteristics, especially energy density. In order to improve the battery characteristics of the lithium-air battery, in addition to the materials used to complete the lithium-air battery, technology that realizes miniaturization and weight reduction and increases discharge voltage by reducing internal resistance is required.

Contents of the invention

Therefore, an object of the present invention is to provide a compact lithium-air battery and a lithium-air battery negative electrode assembly capable of suppressing extreme enlargement even when energy density and input/output density are increased compared with conventional air batteries.

In order to solve the problem, the lithium-air battery of the present invention includes a negative electrode composite body and an air electrode, and the negative electrode composite body includes: a plate-shaped or wire-shaped negative electrode current collector; two negative electrode layers in a plate shape, which are made of metal Lithium, an alloy mainly composed of lithium, or a compound mainly composed of lithium, and a part of the negative electrode current collector is sandwiched therebetween; two separator layers in the shape of a plate, which are lithium ion conductive made of glass ceramics, sandwiching the other part of the negative electrode collector and all of the two negative electrode layers; and a junction that exposes the remaining part of the negative electrode collector to the two separators. The outer side between the layers is closed between the outer peripheral portions of the two isolation layers; the air electrode includes: an air electrode layer, which contains a conductive material and is connected to at least one of the two isolation layers opposite; and a plate-shaped or wire-shaped air electrode current collector, which is electrically connected to the air electrode layer.

In addition, the negative electrode complex of the lithium-air battery of the present invention includes: a plate-shaped or linear negative electrode current collector; two plate-shaped negative electrode layers, which are made of metal lithium, an alloy mainly composed of lithium, or The compound of the main component is formed, and a part of the negative electrode collector is sandwiched therein; the two separators in the shape of a plate are made of glass ceramics with lithium ion conductivity, and the negative electrode collector another part and the whole of the two negative electrode layers are sandwiched therebetween; and a joint part which exposes the remaining part of the negative electrode current collector to the outside between the two separator layers and joins the two separator layers Closed between the outer peripheral parts.

In other technical schemes, the lithium-air battery of the present invention includes a negative electrode composite body and an air pole; the negative electrode composite body includes: a plate-shaped or linear negative electrode current collector; two negative electrode layers in a plate shape, which are made of lithium metal , an alloy with lithium as the main component or a compound with lithium as the main component, and a part of the negative electrode collector is sandwiched therein; two separator layers in the shape of a plate, which connect the two negative electrode layers all sandwiched therein, and have lithium ion conductivity; and a spacer, which is disposed between the two separator layers so that the two negative electrode layers are surrounded, and spaced between the two separator layers airtight; the air electrode includes: an air electrode layer, which contains a conductive material and is opposite to at least one of the two isolation layers; and a plate-shaped or wire-shaped air electrode collector, which is electrically connected to the The air pole layer.

In other technical solutions, the negative electrode complex of the lithium-air battery of the present invention includes: a plate-shaped or linear negative electrode current collector; two plate-shaped negative electrode layers, which are made of metal lithium, an alloy with lithium as the main component or a compound containing lithium as the main component, and sandwiching a part of the negative electrode current collector; two separator layers in the shape of a plate, which sandwich the entirety of the two negative electrode layers, and have lithium ion conductivity; and a gasket disposed between the two isolation layers so as to surround the two negative electrode layers and seal the space between the two isolation layers.

According to the present invention, it is possible to provide a compact lithium-air battery and a lithium-air battery negative electrode assembly capable of suppressing extreme enlargement even when energy density and input/output density are increased compared with conventional air batteries.

Description of drawings

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

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

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

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.

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

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

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

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

9 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

10 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

11 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

12 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

13 is a schematic perspective view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

14 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

15 is a perspective view illustrating a disassembled state and an assembled state of the negative electrode assembly of the battery of Example 1. FIG.

FIG. 16 is a perspective view illustrating a disassembled state of the battery of Comparative Example 1. FIG.

17 is a graph showing transitions in discharge voltages of batteries of Example 1 and Comparative Example 1. FIG.

Fig. 18 is a graph showing impedance spectroscopy.

19 is a perspective view illustrating a disassembled state and an assembled state of the negative electrode assembly of the battery of Example 2. FIG.

20 is a graph showing transitions in discharge voltages of batteries of Examples 2 and 3. FIG.

FIG. 21 is a schematic diagram showing the structure of a battery of Example 4. FIG.

FIG. 22 is a graph showing transitions in discharge voltages of batteries of Examples 4 and 5. FIG.

FIG. 23 is a graph showing transitions in discharge voltages of batteries of Examples 8 and 9. FIG.

Explanation of reference signs

1. 1A lithium-air battery; 2. Shell; 3. Contact holding layer; 4. Collector junction; 5. 5a, 5b negative electrode collector; 5a1, 5b2 negative terminal; Electric body; 7 electrolyte; 8, 8A, 8B, 8C, 8D, 8E, 8F, 8G negative electrode complex; 9, 9A air electrode; 11 air battery cell; 12 isolation layer; 13, 13A air electrode layer; 13a broken line; 13b plane part; 15 negative electrode layer; 15c folded part; 16 junction; 17 buffer layer; 18 gasket; 19 peripheral sealing member; 20 gasket alignment surface; 22 gasket; , 105A, 105B negative electrode current collector (copper foil); 108, 108A, 108B negative electrode complex; 109B air electrode; 112, 112A, 112B isolation layer (solid electrolyte); 103A contact holding layer; 104A brazing part; 115, 115A, 115B negative electrode layer (metal lithium); 117, 117A buffer layer (cellulose separator); 117B buffer layer (polymer electrolyte); 118, 118A, 118B gasket; 119, 119A, 119B epoxy adhesive ; 122B rubber gasket; 123B epoxy adhesive; 201 lithium-air battery; 202 aluminum lamination coating material; 205 negative electrode collector (copper foil); Air pole; 212 separation layer (solid electrolyte); 215 negative electrode layer (metal lithium); 217 buffer layer; 219 water retention layer.

detailed description

Embodiments of the lithium-air battery and the negative electrode assembly of the lithium-air battery according to the present invention will be described with reference to FIGS. 1 to 23 .

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 , the lithium-air battery 1 of the present embodiment includes a casing 2 as an outer casing, and a negative electrode current collector 5 drawn out from the casing 2 and exposed to the casing 2, and an air electrode as a positive electrode current collector. Collector 6.

The casing 2 is a gas-permeable but liquid-impermeable material such as polyethylene, polypropylene, or a molded product of fluororesin formed from a fluoropolymer having a vinylidene fluoride unit and a tetrafluoroethylene unit. A porous body of fluororesin formed of a fluoropolymer of difluoroethylene units and tetrafluoroethylene units, and the housing 2 is a hollow body in the shape of a hexahedron such as a rectangular parallelepiped. In addition, the casing 2 may be a molded product of a material impermeable to both gas and liquid. In this case, ventilation openings are provided on the side walls of the housing 2 . The air vent is provided at a position where the electrolyte 7 described later will not leak out, and allows air to circulate 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 .

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

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

In addition, although the adjacent negative electrode assembly 8 and the air electrode 9 are actually in contact with each other, in FIG. 2 , they are shown with a gap between them for easy identification.

As shown in FIGS. 2 and 3 , the lithium-air battery 1 of this embodiment includes a casing 2, an electrolyte 7, a plurality of negative electrode assemblies 8, and a plurality of air electrodes 9, and the casing 2 accommodates the negative electrode assemblies 8 and the air electrodes. 9. The plurality of negative electrode assemblies 8 and the plurality of air electrodes 9 are alternately stacked on top of each other, and the electrolyte 7 is stored in the casing 2, at least in contact with the air electrodes 9, responsible for the connection between the air electrodes 9 and the negative electrode assemblies. Conduction of lithium ions between 8.

One side of the negative electrode assembly 8 and the side of the air electrode 9 facing it is an air battery cell 11 . That is, the lithium-air battery 1 is a battery obtained by connecting air battery cells 11 in parallel in the number of positions where the negative electrode assembly 8 and the air electrode 9 face each other.

The plurality of negative electrode assemblies 8 and the plurality of air electrodes 9 each have a plate shape. In addition, a plurality of negative electrode assemblies 8 are electrically connected in parallel, and a plurality of air electrodes 9 are electrically connected in parallel.

The air electrode 9 presents a larger projected area than the negative electrode assembly 8 . Specifically, the air electrode 9 has a quadrangular shape that is slightly larger than the quadrangular flat plate-shaped negative electrode assembly 8 .

In addition, the air electrode 9 includes an air electrode layer 13 and an air electrode current collector 6. The air electrode layer 13 contains a conductive material and is opposed to at least one surface of the negative electrode assembly 8 (that is, one surface of the separator 12 described later). , the air electrode current collector 6 is in the shape of a plate or a wire, and is electrically connected to the air electrode layer 13 .

The air electrode layer 13 is made of a conductor such as carbon fiber, and is in the shape of a thin plate. Specifically, examples of the air electrode layer 13 include a porous structure such as a grid structure in which constituent fibers are regularly arranged, a non-woven fabric structure in which constituent fibers are randomly arranged, and a three-dimensional mesh structure. Specifically, it is carbon materials such as carbon cloth, carbon nonwoven fabric, and carbon paper. In addition, as another material having a porous structure, for example, metal materials such as stainless steel, nickel, aluminum, and iron may be used. As a preferable material for the air electrode layer, a lightweight material with high corrosion resistance is preferable, and an air electrode layer formed of the above-mentioned carbon material is desired. The air electrode layer 13 sucks up the electrolyte 7 through capillary phenomenon and makes it interposed between the negative electrode assembly 8 and the air electrode 9 . The air electrode layer 13 may contain catalysts such as noble metals and metal oxides. As the catalyst, any catalyst may be used as long as it promotes the reduction reaction of oxygen during discharge and the oxidation reaction of oxygen during charge. 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 _0.4 FeO ₃ , Metal oxides such as 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 , noble metals such as Au, Pt, Ag, and complexes of these substances. The method for producing the catalyst-containing air electrode layer 13 is not particularly limited, and it can be performed, for example, by mixing carbon carrying catalyst metals such as platinum with a binder (binder) and an organic solvent ( paste) attached to carbon cloth, etc. As an organic solvent, for example, N-methyl-2-pyrrolidone (NMP), acetonitrile, dimethylformamide (DMF), dimethylacetamide (DMA) and dimethyl sulfoxide (DMSO), acetone, ethanol, , 1-propanol, etc. Examples of the binder include polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and the like. Specific methods of attaching the catalyst to the air electrode layer 13 include a method of applying and attaching the above-mentioned paste by a doctor blade method or a spraying method.

The air electrode current collector 6 should just exist stably within the operating range of the lithium-air battery and have 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.

A water holding layer is optionally arranged between the air electrode 9 and the negative electrode assembly 8 . The water holding layer absorbs and holds the electrolyte 7 , so that the electrolyte 7 easily exists between the air electrode 9 and the negative electrode assembly 8 . The water retaining layer is preferably a porous and foamable sheet capable of impregnating and retaining the electrolyte, and examples include cellulose, chemical fiber nonwoven fabric, PP (polypropylene) resin, PE (polyethylene) Polymer film such as resin, PI (polyimide) resin, etc.

Electrolyte 7 is an aqueous electrolyte. In addition, the electrolyte 7 may be in contact with the negative electrode assembly 8 . The aqueous electrolyte is, for example, lithium chloride aqueous solution or the like.

In addition, the electrolyte 7 may also be a polymer electrolyte. In this case, the electrolyte 7 is a thin film sandwiched between the air electrode 9 and the negative electrode assembly 8 , or a thin film coated on the surface of the air electrode layer 13 .

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.

In addition, although the adjacent negative electrode assembly 8 and the air electrode 9A are actually in contact with each other, in FIG. 4 , they are shown with a gap between them for easy identification.

In addition, in the lithium-air battery 1A, the same components as those of the lithium-air battery 1 are denoted by the same reference numerals, and redundant descriptions are omitted.

As shown in FIG. 4 , the air electrode layer 13A of the air electrode 9A of the lithium-air battery 1A of the present embodiment is bent in a zigzag manner. The plurality of negative electrode assemblies 8 are sandwiched between the plane portions 13b between the fold lines 13a and the fold lines 13a of the air electrode layer 13A.

For one air electrode layer 13A sandwiching a plurality of negative electrode assemblies 8 therein, only one air electrode collector 6 is required, and compared with the air electrode collector 6 of the lithium-air battery 1, the number of air electrodes can be reduced. Number of layers, total extension length, weight and volume.

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

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

As shown in Fig. 5 and Fig. 6, the negative electrode assembly 8 of lithium-air battery 1, 1A comprises: plate-shaped or linear negative electrode current collector 5; two negative electrode layers 15 of plate shape, these two negative electrode layers 15 are made of It is made of metal lithium, an alloy mainly composed of lithium, or a compound mainly composed of lithium, and a part of the negative electrode current collector 5 is sandwiched therein; two separators 12 in the shape of a plate, the two separators 12 are composed of Lithium ion conductive glass ceramics, sandwiching the other part of the negative electrode current collector 5 and all of the two negative electrode layers 15; and the junction 16, which exposes the remaining part of the negative electrode current collector 5 to the two between the outer sides of the spacer layers 12, and join the outer peripheral portions of the two spacer layers 12 to close them.

In addition, the negative electrode assembly 8 includes a buffer layer 17 having lithium ion conductivity and separating the negative electrode layer 15 from the separator layer 12 .

That is, the negative electrode assembly 8 has a packaging structure in which the two bonded negative electrode layers 15 are wrapped with the buffer layer 17 , and the buffer layer 17 is wrapped with the two separator layers 12 and the junction part 16 .

The material of the negative electrode current collector 5 should only be able to exist stably within the operating range of the lithium-air battery and have desired conductivity. For example, copper, nickel, etc. are mentioned.

The two negative electrode layers 15 have substantially the same quadrangular flat plate shape, and are bonded with a part of the negative electrode current collector 5 sandwiched therebetween. In the present embodiment, the negative electrode current collector 5 is integrally formed with a strip-shaped terminal portion in a quadrangular plate-shaped portion having substantially the same size as the negative electrode layer 15 . However, depending on the purpose, the negative electrode current collector 5 is in contact with at least a part of the negative electrode layer 15 but is not in contact with the entire opposite surface of the two negative electrode layers 15 and is sandwiched by the two negative electrode layers 15, which also belongs to the technology of the present invention. scope. The shape and size of the negative electrode current collector 5 can be appropriately determined by those skilled in the art.

In addition, it is desirable that negative electrode layer 15 is made of metallic lithium. The negative electrode layer 15 may be an alloy mainly composed of lithium or a compound mainly composed of lithium instead of metallic lithium. Alloys mainly composed of lithium may contain sodium, potassium, magnesium, calcium, aluminum, silicon, germanium, tin, lead, antimony, bismuth, silver, gold, zinc, indium, and the like. Compounds mainly composed of lithium include Li _3-x M _x N (M=Co, Cu, Ni).

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

When the negative electrode layer 15 is in contact with the separator layer 12 , lithium in the negative electrode layer 15 may react with the glass ceramic of the separator layer 12 . For example, when the material of the isolation layer 12 is LTAP, there is a possibility that LTAP may be degraded by reaction with lithium. However, such a reaction is suppressed by interposing the buffer layer 17 to prevent contact between the anode layer 15 and the separator layer 12 . This helps to prolong the life of Li-air batteries 1 .

The buffer layer 17 may also be a solid polymer electrolyte in which the lithium salt is dispersed in the polymer, a separator impregnated with an organic electrolyte in which the lithium salt has been dissolved, or obtained by swelling the polymer with an organic electrolyte in which the lithium salt is dissolved. The gel electrolyte of the gel-like polymer electrolyte or the separator containing the gel electrolyte.

(a) Solid polymer electrolyte as a buffer layer

The main polymer is PEO (polyethylene oxide), PPO (polypropylene oxide), or the like. Lithium salts are LiPF ₆ (lithium hexafluorophosphate), LiClO ₄ (lithium perchlorate), LiBF ₄ (lithium tetrafluoroborate), LiTFSI(Li(CF ₃ SO ₂ ) ₂ N), Li(C ₂ F ₄ SO ₂ ) ₂ N, LiBOB (lithium dioxalate borate), etc.

In addition, when PEO is used as a solid polymer electrolyte, the molecular weight of PEO is desirably 10 ⁴ to 10 ⁵ , and the molar ratio between PEO and lithium salt is desirably 8:1 to 30:1.

In order to improve the strength and electrochemical properties of the buffer layer 17, powder of a ceramic filler such as BaTiO ₃ may also be dispersed in the polymer. The compounding quantity of a ceramic filler is desirably 1-20 weight part with respect to 100 weight part of remaining components.

(b) Diaphragm as buffer layer

In addition, the buffer layer 17 may be a member in which an organic electrolyte is impregnated into a separator (sheet of porous polyethylene, polypropylene, cellulose, etc.). In this case, the organic electrolyte used for the buffer layer 17 is a mixture of diethyl carbonate and dimethyl carbonate in ethylene carbonate, and LiPF ₆ (lithium hexafluorophosphate) and LiClO ₄ (lithium perchlorate) are further added. , LiBF ₄ (lithium tetrafluoroborate), LiTFSI (Li(CF ₃ SO ₂ ) ₂ N), Li(C ₂ F ₄ SO ₂ ) ₂ N, and LiBOB (lithium dioxalate borate). By using such a separator, lithium ion conductivity can be provided, and the thickness of buffer layer 17 can also be reduced.

(c) Gel electrolyte as a buffer layer

The 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 used as the main body of the gel electrolyte is PEO (polyethylene oxide), PVA (polyvinyl alcohol), PAN (polyacrylonitrile), PVP (polyvinylpyrrolidone), PEO-PMA (polyethylene oxide modified polymethylene Cross-linked body of acrylate), PVDF (polyvinylidene fluoride), PVDF-HFP (copolymer of polyvinylidene fluoride and hexafluoropropylene), etc. The organic electrolyte is, for example, LiPF ₆ (lithium hexafluorophosphate), LiClO ₄ (lithium perchlorate), LiBF ₄ (lithium tetrafluoroborate), LiTFSI (Li(CF ₃ SO ₂ ) ₂ N), Li(C ₂ F ₄ SO ₂ ) ₂ N, LiBOB (lithium dioxalate borate) Lithium salt and other substances obtained. The solvent of the organic electrolyte can be mixed in any ratio. Preferably, the concentration of the lithium salt in the organic electrolyte is 1 (mol/L)˜1.3 (mol/L). Preferably, the ratio of the polymer in the gel electrolyte is in the range of 3% by mass to 7% by mass in the gel electrolyte. By setting the ratio of the polymer within this range, desired ion conductivity and a viscosity optimal for producing the negative electrode assembly can be satisfied. The thickness of the gel electrolyte is 10 μm to 100 μm, preferably 50 μm or less. In addition, the amount of the gel electrolyte as a buffer layer is desirably a filling amount capable of appropriately (neither excessively nor insufficiently) improving the adhesion with respect to the entire opposing surface between the negative electrode layer 15 and the separator layer 12 . By using the gel electrolyte, it is easier to prevent air bubbles from being mixed in compared with the case where 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 elements.

For lithium-ion batteries, it is known in the past that the ion conductivity is better when there is no polymer electrolyte such as gel electrolyte between the members, but the inventors have found for the first time that if the gel electrolyte is used as the buffer layer 17, then the same Compared with the use of a cellulose separator impregnated with an organic electrolyte, the discharge voltage is further increased, and a long-term stable lithium-air battery can be obtained. The theoretical reason why the battery characteristics are improved by using the gel electrolyte is unclear, but it is presumed that the contact between the negative electrode layer 15 and the separator 12 is improved because the gel electrolyte can follow the unevenness of the surface of the negative electrode layer 15 and the separator 12. Therefore, the discharge voltage can be increased. In addition, in a lithium-air battery, lithium ions are eluted from the negative electrode layer 15 during discharge, so the volume of the negative electrode layer 15 sometimes decreases, but the gel electrolyte can also follow the reduced volume of the negative electrode layer 15 to maintain the negative electrode. Contact between layer 15 and isolation layer 12. Therefore, it is presumed that an increase in internal resistance caused by a decrease in the adhesion between the negative electrode layer 15 and the separator layer 12 is suppressed, and the discharge voltage can be maintained for a long time.

Furthermore, since the gel electrolyte is in the form of a gel, when the negative electrode layer 15 and the separator 12 are combined to assemble the negative electrode assembly, the combination can be easily performed and the workability is excellent. The gel electrolyte is also excellent in workability in that it is less likely to leak when making negative electrode complexes and single cells, and it is also less likely to cause leakage from the gaps of the single cells after manufacture, so the performance variation of each single cell is reduced. The advantages. In addition, the high viscosity of the gel electrolyte suppresses the contact of the organic electrolyte with the gasket and the peripheral sealing member, and can alleviate the deterioration of adhesives, resins, etc. used as the gasket and the peripheral sealing member. As a result, there is an effect that the airtightness of the negative electrode assembly and the cell can be ensured for a long period of time. In addition, there is an advantage that the degree of freedom of selection of the material of the gasket and the outer peripheral seal member is improved.

In addition, the gel electrolyte is preferably one in which powder insoluble in the organic electrolyte is dispersed. By dispersing the powder insoluble in the organic electrolyte in the gel electrolyte, there is an effect of preventing direct contact between the separator layer 12 and the negative electrode layer 15 . As the powder dispersed in the gel electrolyte, as long as it is a fine powder that does not dissolve in the organic electrolyte, the powder that does not react with the members inside the negative electrode assembly and does not cause its deterioration is preferred, and it is particularly preferable to make the resin into a fine powder. pink. The resin powder is not particularly limited as long as it is insoluble in the organic electrolyte, but it 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 also be a ceramic filler. The particle size of the powder is about greater than 1 μm and less than 50 μm, preferably an ultrafine powder with an average particle size of about 5 μm. By setting the average particle diameter of the powder within this range, there is an effect that the influence on battery performance can be reduced. Here, the average particle diameter is a value measured by a laser diffraction scattering particle size distribution measuring device. The amount of powder dispersed in the gel electrolyte is preferably 0.5% by mass to 5% by mass, more preferably 0.5% by mass to 1.5% by mass in the gel electrolyte. By setting the dispersion amount of the powder within this range, there is an effect that the influence on battery performance can be reduced. In addition, by reducing the dispersion amount of the powder to 1% by mass or less, the influence on the viscosity of the gel electrolyte is reduced.

In order to improve the strength and electrochemical properties of the gel electrolyte, it is also possible to further disperse the powder of ceramic filler such as BaTiO ₃ in the gel electrolyte. The compounding quantity of a ceramic filler is desirably 1-20 weight part with respect to 100 weight part of remaining components.

(d) Separator containing gel electrolyte as a buffer layer

The gel electrolyte-containing separator is a separator obtained by impregnating or holding the above-mentioned gel electrolyte in a lithium ion battery separator (a sheet of porous polyethylene, polypropylene, cellulose, or the like). In the separator of the gel electrolyte, the weight ratio of the gel electrolyte to the separator is preferably 7:1 to 30:1. The separator containing the gel electrolyte may be used only one sheet, or a plurality of sheets may be stacked and used. The preferred number of separators containing the gel electrolyte is 1 to 4 depending on the material and thickness of the separator. The separator containing the gel electrolyte can increase the discharge voltage and maintain the discharge voltage for a long time, similarly to the gel electrolyte of (c) above. This is considered to be because, even when the volume of the negative electrode layer 15 is reduced, the contact between the negative electrode layer 15 and the separator layer 12 is maintained, thereby reducing the contact resistance. In addition, by including the gel electrolyte in the separator, the workability of inserting the buffer layer 17 in the production of the negative electrode assembly is improved, the reproducibility of the electrochemical characteristics of the single cell is improved, and the yield at the time of manufacture is improved. In addition, by using a separator containing a gel electrolyte, contact of the organic electrolyte with the gasket and the peripheral sealing member is suppressed. Therefore, deterioration of adhesives, resins, and the like used as the gasket and the peripheral sealing member can be alleviated, and the airtightness of the negative electrode assembly and the battery can be ensured for a long period of time.

Here, the buffer layer 17 is not necessarily provided in the negative electrode assembly 8 and is an arbitrary component. That is, in the negative electrode assembly 8 , the negative electrode layer 15 may be arranged directly adjacent to the separator layer 12 without interposing the buffer layer 17 .

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

Separator layer 12 has a quadrangular flat plate shape slightly larger than negative electrode layer 15 , and sandwiches the entirety of two negative electrode layers 15 formed integrally. That is, the central portion of the separator 12 faces the negative electrode layer 15 , and the outer peripheral portion of the separator 12 protrudes toward the outer periphery of the negative electrode layer 15 like a flange or a cornice.

In addition, the isolation layer 12 is glass ceramics having water resistance and lithium ion conductivity. It is desirable that the lithium ion conductivity of the separation layer 12 is 10 ^-5 S/cm or more. As the spacer layer 12 , for example, a NASICON (Na Superionic Conductor: sodium superionic conductor) type lithium ion conductor can be mentioned. In addition, as the spacer layer 12, lithium ions represented by the general formula LiM ₂ (PO ₄ ) ₃ (M is a tetravalent cation such as Zr, Ti, Ge, etc.) by replacing with a trivalent cation M′ such as In or Al can be cited. A part of the tetravalent cation M of the conductor improves the lithium ion conductivity and is a lithium ion conductor represented by the general formula Li _1+x M _2-x M' _x (PO ₄ ) ₃ . In addition, as the separation layer 12, a lithium ion conductor represented by the general formula LiM ₂ (PO ₄ ) ₃ (M is a tetravalent cation such as Zr, Ti, Ge, etc.) by replacing it with a pentavalent cation M" such as Ta can be cited. A part of the 4-valent cation M, which improves the lithium ion conductivity, is a lithium ion conductor represented by the general formula Li _1-x M _2-x M” _x (PO ₄ ) ₃ . Sometimes P of these lithium ion conductors is replaced by Si, and from the viewpoint of ion conductivity, it is desirable to express it with the general formula Li _1+x+y Ti _2-x Al _x P _3-y Si _y O ₁₂ (LTAP) lithium ion conductor.

The joining portion 16 is provided between the respective outer peripheral edge portions of the two spacers 12 . The joint portion 16 closes a region sandwiched between the two separator layers 12 , and seals a part of the negative electrode current collector 5 , the two negative electrode layers 15 and the buffer layer 17 in this region in cooperation with the two separator layers 12 .

In addition, in the joint portion 16, an adhesive material such as an epoxy resin adhesive, a silicone adhesive, or a styrene-butadiene rubber adhesive is filled between the respective outer peripheral portions of the two spacers 12 to make them cured parts. The joint portion 16 is to face both the buffer layer 17 and the electrolyte 7, and therefore, it is preferable that it has organic electrolyte resistance and alkali resistance.

In addition, the joining part 16 may be what filled and hardened resin instead of an adhesive agent.

In the lithium-air battery 1 and the negative electrode assembly 8 of the present embodiment, both surfaces of the plate-shaped negative electrode assembly 8 participate in power generation. By making the negative electrode assembly 8 double-sided, the area effective for the battery reaction per the same volume is doubled compared with the conventional lithium-air battery, and the input/output density can be improved.

In addition, the lithium-air battery 1 and the negative electrode assembly 8 of the present embodiment do not require the lamination film in the conventional lithium-air battery, the number of elements can be reduced, and there is no need for the laminated film between polypropylene and glass ceramics. Difficult bonding in joints. Furthermore, it is easy to stack the negative electrode assembly 8 and the air electrode 9 into one air battery cell 11 .

Compared with the conventional lithium-air battery in which an aqueous electrolyte is contained in each unit cell in which the negative electrode assembly and the air electrode are paired, the lithium-air battery 1 and the negative electrode assembly 8 of the present embodiment combine a plurality of air battery cells. The batteries 11 are connected in parallel and accommodated in one case 2 . According to this structure, the lithium-air battery 1 and the negative electrode assembly 8 of the present embodiment do not require a separator for each air battery cell 11 (corresponding to the case of a conventional lithium-air battery), and the plurality of air battery cells 11 By sharing the electrolyte 7, it is possible to optimize the stored amount of the electrolyte 7 as a whole of the lithium-air battery 1, thereby reducing weight and volume. In addition, since the separator for each air battery unit cell 11 is unnecessary, the structure becomes simple and the number of components can be reduced.

Moreover, when the lithium-air battery 1 and the negative electrode assembly 8 of the present embodiment store the aqueous electrolyte as the electrolyte 7 in the case 2, when the electrolyte 7 volatilizes with the progress of the discharge, it can also be continuously released to the air. Electrolyte 7 is supplied to pole 9 . Thus, the lithium-air battery 1 and the negative electrode assembly 8 of the present embodiment do not need to replenish the electrolyte 7 for a long period of time, and performance degradation caused by a shortage of the electrolyte 7 is prevented.

Furthermore, since the lithium-air battery 1 and the negative electrode assembly 8 of the present embodiment use the joint portion 16 to join the two separators 12, the difficult adhesion between the polypropylene and the glass ceramics of the laminated film is difficult. Compared with that, it can be easily manufactured.

Therefore, according to the lithium-air battery 1 and the negative electrode assembly 8 of this embodiment, even when the energy density and the input/output density are increased compared with conventional air batteries, it is possible to suppress extreme enlargement and form it compactly.

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

As shown in FIG. 7 , an anode composite 8A includes an anode current collector 5 , two anode layers 15 , two separator layers 12 , a buffer layer 17 , a gasket 18 , and a peripheral sealing member 19 . Components denoted by the same reference numerals have the same configurations as those in the embodiment described in FIGS. 5 and 6 , and redundant descriptions will be omitted. Negative electrode assembly 8A can be used instead of negative electrode assembly 8 in lithium-air batteries 1 and 1A.

In this embodiment, the spacer 18 is disposed between the two separator layers 12 so as to surround the outer periphery of the negative electrode layer 15 , and the negative electrode layer 15 is disposed within the frame of the spacer 18 . The spacers 18 may be fixed on the respective inner surfaces of the isolation layers 12 by any method, but it is preferable to use the adsorption and/or adhesive properties of the spacers 18 themselves to achieve the fixation. The spacer 18 may be in contact with the outer periphery of the negative electrode layer 15 , or may be separated from the outer periphery of the negative electrode layer 15 . The spacer 18 consists of two spacers which are superimposed after being arranged on the respective inner surfaces of the two insulating layers 12 . The superimposed surfaces 20 of the two gaskets are preferably tightly bonded by utilizing the adsorption and/or adhesive properties of the gaskets themselves, so as to seal the space in the gasket 18 . The negative electrode current collector 5 is drawn to the outside of the negative electrode assembly 8A through the superimposed surface 20 . Alternatively, the spacer 18 may be formed as a single member. In this case, a through hole through which the negative electrode current collector 5 passes is provided in the spacer 18 .

The gasket 18 is not particularly limited as long as it is a rubber or elastomer resistant to organic electrolytes, but rubber or elastomer formed by ethylene-propylene-diene copolymerization, or fluorine-based rubber or elastomer is preferable. Examples of the rubber formed by copolymerization of ethylene-propylene-diene include EPM, EPDM, and EPT. Examples of the fluorine-based rubber or elastomer include vinylidene fluoride-based (FKM), tetrafluoroethylene-propylene-based (FEPM), tetrafluoroethylene-perfluorovinyl ether-based (FFKM), and the like. The physical properties of the rubber or elastomer are preferably softer hardness. The hardness of the gasket material is preferably about Shore A50 to Shore A70. When the gasket material is too soft, there may be problems such as poor processability. By making the gasket 18 relatively soft in hardness and rubber elasticity, the constituent members inside the negative electrode assembly 8A can be adjusted to have a uniform height. That is, by directly or indirectly pressing one or both of the spacer layers 12 , the adhesiveness of the entire contact surface between the buffer layer 17 and the spacer layer 12 can be improved. This also improves the contact between the separator layer 12 and the negative electrode layer 15 via the buffer layer 17 . In addition, it is preferable that the rubber or elastic body is of a type in which the raw material before molding is liquid and has high adsorption and/or adhesiveness.

The spacer 18 is preferably in the shape of a quadrangular window frame. The spacer 18 has an inner dimension capable of arranging the negative electrode layer 15 in the frame, and has an outer dimension substantially the same as that of the separator 12 . The thickness of the spacer 18 may be approximately the same as the total thickness of the constituent members laminated between the separator layers 12 .

The peripheral sealing member 19 is disposed on the peripheral ends of the two separators 12 to expose the remaining part of the negative electrode current collector to the outside between the two separators and to hermetically seal the gap between the two separators. The outer peripheral seal member 19 is disposed over the entire circumference of the outer peripheral edges of the two insulating layers 12 so as to cover the gap between the two insulating layers. The peripheral sealing member 19 is preferably in contact with the gasket 18, fixing the spacer 12 and the gasket 18 from the outside. The sealing performance of the negative electrode assembly 8A can be further improved by the outer peripheral sealing member 19 . The outer peripheral sealing member 19 is not particularly limited as long as it can hermetically seal between the two separator layers and can shrink in the thickness direction of the negative electrode assembly 8A, and is preferably an adhesive. As the adhesive, an adhesive with low moisture permeability and high airtightness is preferable, for example, epoxy-based adhesives, acrylic-based adhesives, silicone-based adhesives, olefin-based adhesives, and Synthetic rubber-based adhesives, etc. More preferably, the adhesive also has resistance to an aqueous electrolyte (preferably an organic electrolyte), and is, for example, an epoxy-based adhesive, an olefin-based adhesive, or the like. Preferably, the adhesive has curing conditions such that it can be cured at room temperature in a short time. In addition, the adhesive used as the outer peripheral sealing member 19 may contain a trace amount of an ethanol-based solvent or the like that degrades metallic lithium. However, since the space between the separators is sealed by the gasket 18, this can be prevented. The ethanol-based solvent enters into the negative electrode assembly 8A. As a result, the degree of freedom in the types of adhesives that can be used for the exterior sealing member 19 can be increased. The binder has a penetrating portion for penetrating the negative electrode current collector 5 .

Alternatively, the outer peripheral sealing member 19 may be a member that presses and clamps the respective outer surfaces of the two spacers 12 near their outer peripheral ends, for example, may be a clamp or the like. In the case where the peripheral sealing member 19 is such a member, when the thickness of the negative electrode layer 15 is reduced due to discharge during use, the negative electrode layer 15 can be made without pressing one or both of the separators 12. The distance from the separator 12 automatically shrinks, and the adhesion between the buffer layer 17 and the separator 12 and the adhesion between the negative electrode layer 15 and the separator 12 through the buffer layer 17 can be maintained. Furthermore, the airtightness between the two isolation layers provided by the spacer 18 can be enhanced. A member such as a clip as the external sealing member 19 can also be used together with the above-mentioned adhesive.

In the negative electrode assembly 8A of this embodiment, by pressing one or both of the separators 12, the adhesion between the separator 12 and the negative electrode layer 15 via the buffer layer 17 can be improved, and as a result, it is possible to Lower the internal resistance and increase the discharge voltage. Even if the thickness of the negative electrode layer 15 is reduced due to discharge during use of the lithium-air battery, the adhesion between the buffer layer 17 and the separator 12 and the adhesion between the negative electrode layer 15 and the separator 12 via the buffer layer 17 will be reduced. When the compatibility is reduced, the distance between the negative electrode layer 15 and the separation layer 12 can be shortened only by directly or indirectly pressing one or both of the separation layers 12, and the distance between the negative electrode layer 15 and the separation layer 12 can be ensured. tightness between. That is, even if the adhesion between the separator 12 and the buffer layer 17 and the separator 12 and the negative electrode layer 15 through the buffer layer 17 is reduced due to discharge, the negative electrode assembly does not need to be disassembled, but only by pressing. The operation can realize the reduction of the internal resistance, that is, the increase of the discharge voltage.

Moreover, in the negative electrode assembly 8A of this embodiment, since the gaskets 18 and the spacer 18 and the separator 12 are fixed by the adsorption and/or adhesion of the gaskets 18, the airtightness of the space in the negative electrode assembly 8A Sex is higher. In addition, the airtightness can be further improved by having the outer peripheral seal member 19 . Therefore, it is possible to prevent moisture and a solution from entering the negative electrode assembly 8A.

In addition, in the negative electrode assembly 8A of this embodiment, since the gaskets 18 and the separator 12 are fixed by the adsorption and/or adhesion of the gaskets 18, the coating of the adhesive acts as a peripheral seal. When the member 19 is used, there is no problem of lateral offset between the spacer 18 and the gasket 18 or between the spacer 12 and the spacer 18. Therefore, there is an effect that the workability in the production process of the negative electrode assembly 8A is improved.

In addition, in the negative electrode assembly 8A of the present embodiment, since the gasket 18 is resistant to the organic electrolyte, even if an organic electrolyte that deteriorates due to the use of an adhesive, resin, etc., in the negative electrode assembly, the gasket 18 will not deteriorate. The airtightness inside the negative electrode assembly 8A can be maintained.

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

As shown in FIG. 8 , in negative electrode assembly 8B, the area ratio of negative electrode layer 15 to separator 12 is higher than in negative electrode assembly 8A, and a part of spacer 18 protrudes outside the end of separator 12 . In addition, the outer peripheral seal member 19 covers the gasket 18 over the entire circumference of the outer peripheral ends of the two isolation layers 12 and is arranged on the outer peripheral edge of the isolation layer 12 . Components denoted by the same reference numerals have the same configurations as those in the embodiment described with reference to FIGS. 5 to 7 , and redundant description thereof will be omitted. Negative electrode assembly 8B can be used instead of negative electrode assembly 8 in lithium-air batteries 1 and 1A.

In the negative electrode assembly 8B of this embodiment, since the area ratio of the negative electrode layer 15 to the separator 12 is high, the size of the negative electrode assembly 8B can be kept compact and the battery capacity can be increased.

9 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

As shown in FIG. 9, the negative electrode assembly 8C includes a first negative electrode current collector 5a, a second negative electrode current collector 5b, a contact holding layer 3, a collector junction 4, two negative electrode layers 15, and two separator layers 12. , buffer layer 17, gasket 18, and outer peripheral sealing member 19. Components denoted by the same reference numerals have the same configurations as those in the embodiment described with reference to FIGS. 5 to 8 , and redundant description thereof will be omitted. The negative electrode assembly 8C can be used instead of the negative electrode assembly 8 in the lithium-air batteries 1 and 1A.

In the present embodiment, the negative electrode current collector is composed of a plate-shaped first negative electrode current collector 5 a and a plate-shaped second negative electrode current collector 5 b. The negative electrode assembly 8C has the contact holding layer 3 between the first negative electrode current collector 5 a and the second negative electrode current collector 5 b. Two negative electrode layers 15 are adjacent to each of the surfaces of the first negative electrode current collector 5 a and the second negative electrode current collector 5 b opposite to the surface in contact with the contact holding layer 3 .

The first negative electrode current collector 5 a and the second negative electrode current collector 5 b have substantially the same rectangular plate shape with substantially the same size as the negative electrode layer 15 . The first negative electrode current collector 5 a is arranged adjacent to one negative electrode layer 15 , and the second negative electrode current collector 5 b is arranged adjacent to the other negative electrode layer 15 , so that two sets (negative electrode current collector - negative electrode layer) are provided. These two sets of structures are arranged such that the first negative electrode current collector 5 a and the second negative electrode current collector 5 b face each other, and the contact holding layer 3 is disposed between the two structures. That is, the negative electrode layer 15 , the first negative electrode current collector 5 a , the contact holding layer 3 , the second negative electrode current collector 5 b , and the negative electrode layer 15 are arranged in this order.

Between the first negative electrode current collector 5a and the second negative electrode current collector 5b, the current collector junction 4 is arranged in a region where the contact holding layer 3 does not exist. The region where the current collector junction 4 is disposed may extend to the negative electrode terminal portion 5a1. The current collector joining portion 4 joins the first negative electrode current collector 5 a and the second negative electrode current collector 5 b and leads them to the outside. The current collector junction 4 integrates and gathers the negative electrode 15 on the side of the first negative electrode current collector 5 a and the negative electrode 15 on the side of the second negative electrode current collector 5 b. As the current collector joining portion 4, there are fusion welding in which objects are melted and joined together, solid-state joining in which solids are joined by caulking or the like, and alloys (solders) with a low melting point are melted without melting the base material itself. The brazing method for joining is not particularly limited as long as it is a joining method for imparting conductivity between the first and second negative electrode current collectors. Specific examples of the current collector joining portion 4 include spot welding, laser welding, ultrasonic welding, and brazing. Among these methods, a joining method in which there is no gap between the negative electrode collectors and the thickness does not increase is more preferable. The current collector junction 4 preferably has resistance to the organic electrolyte in order to be exposed to the organic electrolyte held by the contact holding layer 3 .

In the present embodiment, the first negative electrode current collector 5a is integrally formed with the negative electrode terminal portion 5a1. The negative electrode terminal portion 5a1 may be formed separately, even if it is not integrally formed with the negative electrode current collector, and connected to the negative electrode current collector. In addition, both the first negative electrode current collector 5 a and the second negative electrode current collector 5 b may be integrally formed with the negative electrode terminal portion, or may be connected to each other.

The contact holding layer 3 has a quadrangular flat plate shape, and has approximately the same dimensions as the first negative electrode current collector 5a and the second negative electrode current collector 5b. The contact holding layer 3 is disposed between the first negative electrode current collector 5 a and the second negative electrode current collector 5 b.

The contact holding layer 3 is a layer having lithium ion conductivity and swelling properties. The contact holding layer 3 absorbs the organic electrolyte to swell, and presses the first negative electrode current collector 5a and the second negative electrode current collector 5b outward, thereby reducing the occurrence of gaps between members inside the negative electrode assembly. In addition, it is preferable that the contact holding layer 3 is sandwiched between two groups (negative electrode collector-negative electrode layer) in a state compressed by the contraction force of the contact holding layer 3 when the negative electrode composite 8C is assembled.

Preferably, the contact holding layer 3 is formed of a resin or rubber porous sheet, a gel-like polymer electrolyte, or a porous and foamed sheet. The contact holding layer 3 contains a lithium ion conductive organic electrolyte absorbed in these materials.

The resin or rubber porous sheet is preferably a spongy foam sheet, and is preferably a sheet swollen with an organic electrolyte in which an electrolyte such as a lithium salt having the same composition as that contained in the negative electrode assembly is dissolved. As the sheet of sponge material, preferably, polyolefin-based, PU (polyurethane) porous sheets of sponge materials such as PP (polypropylene) resin and PE (polyethylene) resin, and porous sheets of rubber sponge can be cited, but It is preferably a material that does not dissolve, deteriorate, etc. due to the organic electrolyte in the negative electrode assembly.

The gel-like polymer electrolyte is a gel electrolyte obtained by swelling a polymer sheet with an organic electrolyte in which an electrolyte such as lithium salt is dissolved. As the material of the polymer sheet, PEO (polyethylene oxide), PVA (polyvinyl alcohol), PAN (polyacrylonitrile), PVP (polyvinylpyrrolidone), PEO-PMA (polyethylene oxide modified polymethyl Cross-linked acrylate), PVdF (polyvinylidene fluoride), PVA (polyvinyl alcohol), PAA (polyacrylic acid), PVdF-HFP (copolymer of polyvinylidene fluoride and hexafluoropropylene) and PPO (polyvinylidene fluoride) Propylene oxide), etc. Examples of lithium salts include LiPF ₆ , LiClO ₄ , LiBF ₄ , LiTFSI (Li(CF ₃ SO ₂ ) ₂ N), Li(C ₂ F ₄ S _O2 ) ₂ N, LiBOB (lithium dioxalate borate), and the like. The solvent of the organic electrolyte can be a single type or a mixture of two or more types, and the mixing ratio is arbitrary. Preferably, the lithium salt concentration in the organic electrolyte is 1 mol/l˜1.3 mol/l. The amount of the polymer in the gel electrolyte is preferably in the range of 3% by mass to 7% by mass in the gel electrolyte. By setting the ratio of the polymer within this range, desired ion conductivity can be satisfied.

The contact holding layer 3 may also be an organic electrolyte or a gel-like polymer electrolyte in which an electrolyte such as a lithium salt having the same composition as that contained in the negative electrode assembly is dissolved and swollen in a separator for a lithium ion battery, such as Among sheets made of porous and/or foamable materials such as polyolefins such as cellulose, PP, and PE, one or more sheets may be stacked.

The thickness of the contact holding layer 3 can be determined according to the contact property between members such as the negative electrode layer and the separator layer in the negative electrode assembly, the storage property of the members, and the workability at the time of manufacturing the composite negative electrode body.

In general, in a lithium-air battery, the internal resistance increases due to a decrease in the adhesion between the negative electrode layer and members such as the separator. In addition, in a lithium-air battery, since lithium ions are eluted from the negative electrode layer during discharge, the volume of the negative electrode layer decreases. Therefore, a gap may be formed between the negative electrode layer and other members, resulting in a decrease in adhesion, an increase in contact resistance, and a decrease in discharge voltage. In particular, when the thickness of the negative electrode such as metal lithium is increased in order to produce a high-capacity battery, the drop in discharge voltage due to the generation of gaps can become conspicuous.

In contrast, in the negative electrode composite 8C of this embodiment, the swellable contact holding layer 3 is arranged between the two groups (negative electrode layer-negative electrode current collector), so that the buffer between the negative electrode layer 15 and the separator 12 is separated. The adhesiveness of the layer 17 is improved, and internal resistance can be reduced. Moreover, although the volume of the negative electrode layer 15 decreases during discharge, since the contact holding layer 3 follows the negative electrode layer 15 by the negative electrode current collector, the generation of a gap between the negative electrode layer 15 and the separator 12 is suppressed, and the negative electrode layer can be maintained. 15 and the isolation layer 12 through the buffer layer 17 of the adhesiveness. In addition, there is an effect that when a deviation in discharge occurs between the two negative electrode layers 15, the contact holding layer 3 can follow each negative electrode layer 15 on one side, and the volume of the negative electrode layer 15 on one side after a larger reduction Adhesion with the isolation layer 12 through the buffer layer 17 is not reduced, and the discharge of the negative electrode layers on both sides is not affected.

Moreover, since it is only the structure in which the negative electrode layer 15 is pasted on one side of the first negative electrode current collector 5a and the second negative electrode current collector 5b, it is different from the case where two negative electrode layers are pasted on both sides of the negative electrode current collector. Compared with this, there is an advantage that making the negative electrode layer 15 thicker makes it easier to manufacture. As a result, the capacity of the lithium-air battery can be increased.

In addition, according to the present embodiment, since the contact holding layer 3 is lithium ion conductive, the internal resistance inside the negative electrode assembly 8C can be reduced, and as a result, the discharge voltage can be increased. Furthermore, by arranging the contact holding layer 3, the amount of the organic electrolyte and/or the gel electrolyte inside the negative electrode assembly 8C increases, so long-term stable battery performance can be obtained.

10 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

As shown in FIG. 10 , in the negative electrode assembly 8D, the first negative electrode current collector 5 a is integrally formed with the negative electrode terminal portion 5 a 1 , and the second negative electrode current collector 5 b is integrally formed with the negative electrode terminal portion 5 b 1 . The negative terminal portions 5 a 1 and 5 b 1 are drawn to the outside of the spacer 18 . The current collector joining portion 4 is arranged between the negative electrode terminal portion 5 a 1 and the negative electrode terminal portion 5 b 1 . Components denoted by the same reference numerals have the same configurations as those in the embodiment described with reference to FIGS. 5 to 9 , and redundant description thereof will be omitted. Negative electrode assembly 8D can be used instead of negative electrode assembly 8 in lithium-air batteries 1 and 1A. The negative electrode assembly 8D of the present embodiment has an effect that the area of the negative electrode current collector is increased and the conduction is increased, which is advantageous for charging and discharging a large current.

11 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

As shown in FIG. 11, in the negative electrode composite body 8E, the first negative electrode current collector 5a and the second negative electrode current collector 5b are integrally formed, and have a folded portion 5c, and the folded portion 5c will be adjacent to the contact holding layer 3. The two planar sections are connected. Furthermore, the two negative electrode layers 15 are integrally formed, and have a folded portion 15 c that connects two planar portions adjacent to the separator layer 12 via the buffer layer 17 . The first negative electrode current collector 5 a is integrally formed with the negative electrode terminal portion 5 a 1 , and the negative electrode terminal portion 5 a 1 is drawn to the outside of the spacer 18 . Between the first negative electrode current collector 5a and the second negative electrode current collector 5b, the current collector junction 4 is arranged in a region where the contact holding layer 3 does not exist. Components denoted by the same reference numerals have the same configurations as those in the embodiment described in FIGS. 5 to 10 , and redundant descriptions will be omitted. Negative electrode assembly 8E can be used instead of negative electrode assembly 8 in lithium-air batteries 1 and 1A. The negative electrode assembly 8E of this embodiment has the effect of reducing the number of elements, improving the operability when manufacturing the negative electrode assembly, and integrating with the contact holding layer 3 by folding back one set (negative electrode current collector-negative electrode layer). .

12 is a schematic cross-sectional view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

As shown in FIG. 12, in the negative electrode composite body 8F, the first negative electrode current collector 5a and the second negative electrode current collector 5b are integrally formed, and have a folded portion 5c, and the folded portion 5c will be adjacent to the contact holding layer 3. The two planar parts are connected. Furthermore, the two negative electrode layers 15 are integrally formed, and have a folded portion 15 c that connects two planar portions adjacent to the separator layer 12 via the buffer layer 17 . The first negative electrode current collector 5a is integrally formed with the negative electrode terminal portion 5a1, and the second negative electrode current collector 5b is integrally formed with the negative electrode terminal portion 5b1. The negative terminal portions 5 a 1 and 5 b 1 are drawn to the outside of the spacer 18 . The current collector joining portion 4 is arranged between the negative electrode terminal portion 5 a 1 and the negative electrode terminal portion 5 b 1 . Components denoted by the same reference numerals have the same configurations as those in the embodiment described in FIGS. 5 to 11 , and redundant descriptions will be omitted. Negative electrode assembly 8F can be used instead of negative electrode assembly 8 in lithium-air batteries 1 and 1A. In the negative electrode assembly 8F of this embodiment, the effect of the negative electrode assembly 8D is added to the effect of the negative electrode assembly 8E.

13 is a schematic perspective view showing another example of the negative electrode assembly of the lithium-air battery according to the embodiment of the present invention.

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

As shown in Figures 13 and 14, in the negative electrode assembly 8G, one of the two separators 12 is at the first dividing line in the plane adjacent to the negative electrode layer 15 and the second dividing line in the same plane. Each is divided, and the gaps between the divided bodies are sealed by the gasket 22 and the adhesive 23 in a state where the divided bodies formed by the division are arranged at the positions before the division. In addition, although omitted in FIG. 13 , as shown in FIG. 14 , the openings of the two spacers 12 are properly sealed by the gasket 18 and the outer peripheral sealing member 19 , and the internal space is sealed. Components denoted by the same reference numerals have the same configurations as those in the embodiment described with reference to FIGS. 5 to 12 , and redundant description thereof will be omitted. Negative electrode assembly 8G can be used instead of negative electrode assembly 8 in lithium-air batteries 1 and 1A.

In this embodiment, the first dividing line is substantially parallel to one side of the separator layer 12 in the plane adjacent to the negative electrode layer 15 , and the second dividing line is substantially perpendicular to the first dividing line. The four divided bodies formed by dividing the spacer layer 12 are bonded at the same arrangement positions as before division using a rubber gasket 22 and an adhesive 23 as sealing members. The gasket 22 is attached to the separator 12 in a cross shape along the dividing line so as to seal the gap between the divided bodies without any gap. The adhesive 23 is applied to the entire spacer 22 and its surrounding surface on the spacer 12 so as to liquid-tightly seal and fix the spacer 22 to the spacer 12 , and then cured. In addition, the adhesive 23 maintains liquid tightness even after curing. The spacer 22 and the adhesive 23 are arranged on the surface opposite to the surface adjacent to the buffer layer 17 so that the separator layer 12 can be bent toward the inside of the negative electrode assembly 8G.

The first dividing line does not necessarily have to be approximately parallel to one side of the isolation layer 12 , but any direction forming an arbitrary angle with one side of the isolation layer 12 may be used. In addition, the second dividing line does not have to be substantially perpendicular to the first dividing line, but can be parallel to the first dividing line or a direction forming an arbitrary angle that crosses the first dividing line. The directions of the first dividing line and the second dividing line are determined so that the separator 12 can be appropriately bent inward of the negative electrode assembly 8G. In addition to the first dividing line and the second dividing line, the isolation layer 12 may be divided by one or more other dividing lines. Another one or more dividing lines may be in the same direction as the first dividing line and the second dividing line, or may be in a different direction. The preferable total number of dividing lines on the separator 12 is, for example, 2 to 4 when one side is about 2 inches. When one side of the separation layer 12 is two inches or more, it is not limited thereto, and it is preferable to increase the number of divisions.

In this embodiment, one of the isolation layers 12 is divided, but both isolation layers 12 may be divided. The direction and number of dividing lines may be the same or different in the two isolation layers 12 .

The spacer 22 is not particularly limited as long as it can bond the divided bodies together, and may be made of elastic other than rubber. Preferably, the rubber or elastomer is resistant to the electrolyte, more preferably a rubber or elastomer formed by copolymerization of ethylene-propylene-diene, or a fluorine-based rubber or elastomer. Examples of the rubber formed by copolymerization of ethylene-propylene-diene include EPM, EPDM, and EPT. Examples of the fluorine-based rubber or elastomer include difluoroacetyl-based (FKM), tetrafluoroethylene-propylene-based (FEPM), tetrafluoroethylene-perfluorovinyl ether-based (FFKM), and the like. The physical properties of rubber or elastomer are preferably soft hardness. The hardness of the gasket material is preferably about Shore A50-70. In the case where the gasket material is significantly soft, there may be problems such as poor processability. By making the gasket 22 have soft hardness and rubber elasticity, the separator 12 can be bent into the negative electrode assembly 8G. In addition, the rubber or elastic body is preferably a material in which the raw material before molding is liquid and has high adsorption and/or adhesiveness.

The adhesive 23 is desirably an adhesive capable of liquid-tightly bonding both the spacer 22 and the separator 12, and is not particularly limited as long as it is elastic and bendable even after curing, but preferably has low moisture permeability. , and high airtight adhesive. The adhesive 23 is, for example, an epoxy-based adhesive, an acrylic adhesive, a silicone-based adhesive, an olefin-based adhesive, a synthetic rubber-based adhesive, etc., and an epoxy-based adhesive is used in the embodiment. Adhesive.

The spacer 22 and the adhesive 23 may be used alone for bonding between the divided bodies. Preferably, the spacer 22 is used together with the adhesive 23, the spacer 22 adheres the divided bodies, and the adhesive 23 is fixed by covering the spacer.

As shown in FIG. 14, in a lithium-air battery, since lithium ions are eluted from the negative electrode layer by discharge, compared with the volume of the negative electrode layer 15 of the negative electrode composite 8G (FIG. 14(a)) before discharge, the discharge In the final negative electrode assembly 8G ( FIG. 14( b )), the negative electrode layer 15 has a reduced volume and a thinner thickness. Since the separator 12 of the negative electrode assembly 8G is formed by joining the split body, if the inside of the negative electrode assembly 8 is decompressed by reducing the volume of the negative electrode layer 15, the joint portion of the split body of the separator 12 will open toward the negative electrode assembly 8G. The inner side is bent to improve the contact between the separator layer 12 and the negative electrode layer 15 via the buffer layer 17 . Therefore, the increase in the internal resistance of the battery after discharge can be suppressed, and the discharge voltage can be maintained for a long period of time.

In particular, when the thickness of the negative electrode layer 15 is thick, the influence of the thinning of the negative electrode layer 15 on the discharge becomes large, but according to the negative electrode assembly 8G of this embodiment, even if the negative electrode layer 15 is thinned, it can maintain the discharge for a long time. discharge voltage. Therefore, in the negative electrode assembly 8G, a negative electrode layer 15 thicker than usual can be used, thereby improving the capacity of the lithium-air battery. For example, in this embodiment, even if the thickness of the negative electrode layer 15 is increased to about twice the thickness of the negative electrode layer when the separator is not divided, the increase in internal resistance due to deep discharge can be reduced.

Furthermore, the adhesive 23 is arranged on the surface of the separator 12 constituting the outer surface of the negative electrode assembly 8G, and the spacer 22 does not contact the organic electrolyte inside the negative electrode assembly 8G. Since the aqueous electrolyte exists outside the negative electrode assembly 8G, the degree of freedom of selection of the binder 23 is increased. In addition, since the binder 23 does not directly contact the organic electrolyte inside the negative electrode assembly 8G, there is also an advantage that deterioration is suppressed and leakage of the organic electrolyte hardly occurs.

【Example】

Hereinafter, the present invention will be specifically described using examples, but the lithium-air battery and negative electrode assembly of the present invention are not limited to the following examples.

[Example 1]

(Production of Negative Electrode Complex)

The negative electrode assembly 108 was produced in the following procedure. FIG. 15 shows the disassembled state and the assembled state of the negative electrode assembly.

(1) As the constituent members of the negative electrode assembly 108, prepare: solid electrolyte 112 (lithium ion conductive glass ceramic (LTAP) sheet, quadrangular, two sheets), metal lithium 115 (square, two sheets, pasted on copper foil (negative electrode) current collector, one sheet, both sides of a quadrangular plate-shaped part and a strip-shaped terminal part), cellulose separator 117 (square, two sheets), and spacer sheet 118 (EPDM, quadrangular frame, two sheets). Spacer sheets 118 are pasted on the two sheets of solid electrolyte 112 .

(2) On a piece of solid electrolyte 112 shown on the lower side in FIG. ₆ ) Drop onto the cellulose septum 117 and penetrate the whole. Lithium metal 115 is arranged on the cellulose separator so as to enter the spacer sheet 118 frame, and the second cellulose separator 117 is arranged on the lithium metal 115 . The organic electrolyte is dropped onto the second cellulose separator 117 and penetrates into the whole.

(3) Cover the upper solid electrolyte 112 prepared in (1) on the upper side of the preparation in (2), paste the upper and lower spacer sheets 118 in a manner that does not deviate, and The adhesiveness of the spacer sheet 118 is used for sealing so that outside air and the like do not enter. The constituent members inside the negative electrode assembly 208 are pressed and fixed as a whole from the outside so that the solid electrolyte 112 and the lithium metal 115 are in contact with each other with good adhesion.

(4) Apply epoxy-based adhesive 119 (two-component room-temperature curing type) thinly to the entire periphery of the solid electrolyte 112 in a manner that seals between two solid electrolytes 112, and make the epoxy-based adhesive The adhesive 119 is cured.

(Production of Air Pole)

Measure 80 mg of platinum-supported carbon (Pt45.8%) as a catalyst for the oxygen reduction of the positive electrode, measure 20 mg of polyvinylidene fluoride (PVdF) as a binder (binder), and add 3 ml of N-methyl -2-pyrrolidone (NMP) to prepare a mixed solvent.

The mixed solvent was stirred and dispersed with a mixer (AR-100 manufactured by THINKY) for 15 minutes, stirred and dispersed with ultrasonic waves for 60 minutes, and coated on carbon cloth with a coater (K202 control coater manufactured by Matsuo Sangyo) After that, it was placed on a heating plate and heated and dried at 110°C for 1 hour to produce an air electrode with a platinum loading capacity of 0.25 mg/cm ² . The current collector of the air electrode was formed by extending the carbon cloth of the air electrode into 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 batteries)

The air electrode, the cellulose sheet dripped with the aqueous electrolyte, the negative electrode complex, and the aqueous electrolyte dripped are housed in a perforated plastic case of a size that can accommodate the negative electrode assembly. The components obtained from the cellulose sheet and the air electrode are used to obtain a lithium-air battery.

[Comparative example 1]

(Production of Negative Electrode Complex)

The negative electrode assembly 208 was produced in the following procedure. The aluminum laminate covering material 202 (PP resin/aluminum/PET resin , four borders). On the other side of the solid electrolyte 212, a cellulose separator is arranged as a buffer layer 217, and is impregnated with an organic electrolyte (EC:EMC=1:1, 1M LiPF ₆ ). Next, metal lithium 215 pasted on one surface of copper foil 205 is arranged on buffer layer 217 . These members are placed between the aluminum laminate covering material 202 for the window material and the aluminum laminate covering material 202 for the outside (PP resin/aluminum/PET resin, quadrilateral) and wrapped to obtain a pouch-shaped battery, Therefore, the ends of the four sides of the aluminum laminate covering material 202 for the outer side and the window material are thermally welded and sealed in a state of being overlapped. The amount of metal lithium used is approximately the same as in Example 1.

(Production of Air Pole)

The air electrode 209 was fabricated in the same manner as in Example 1. 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 batteries)

The structure of the battery of Comparative Example 1 is shown in FIG. 16 in a disassembled state. The lithium air battery 201 was obtained by sequentially stacking the water holding layer 219 (cellulose sheet dripped with an aqueous electrolyte) and the air electrode 209 on the negative electrode assembly 208 of Comparative Example 1 without shifting.

[Discharge test 1]

For the batteries of Example 1 and Comparative Example 1, the discharge voltage when discharged at 4 mA/cm ² (about 0.1 C discharge rate) for 6 hours was measured with an electrochemical analyzer ALS608A manufactured by BAS Corporation. Here, 1C refers to the constant current discharge of a battery with a nominal capacity, and the current value exactly after 1 hour of discharge. The measurement results of the discharge voltage are shown in FIG. 17 . As shown in FIG. 17 , the battery of Example 1 showed a higher discharge voltage than the battery of Comparative Example 1 at all measurement times. The average discharge voltage was 1.56 V in the battery of Example 1, and 0.65 V in the battery of Comparative Example 1, and the value of the battery of Example 1 was twice or more.

[Impedance evaluation]

Impedances in the range of 1 MHz to 10 mHz of the battery of Example 1 and the battery of Comparative Example 1 were measured using a frequency response analyzer (FRA) 1255B manufactured by Solartron Corporation. The measurement results thereof (Nyquist curve) are shown in FIG. 18 . Z' represents the real number part, and Z" represents the imaginary number part. According to the Nyquist curve shown in FIG. Thus, since the battery of Example 1 and the battery of Comparative Example 1 used the air electrodes made under the same conditions, it is considered that the low level of impedance of the battery of Example 1 is caused by the internal resistance in the negative electrode composite In addition, in the battery of Example 1, since the internal resistance of the negative electrode composite was low, it is considered that the discharge voltage shown in FIG. 17 shows a high value.

[Example 2]

(Production of Negative Electrode Complex)

In an atmosphere of Ar gas having an oxygen concentration of 1 ppm or less and a dew point of −76° C. dp, a negative electrode assembly 108A (corresponding to a theoretical capacity of 336 mAh) was produced in the following procedure. FIG. 19 shows a disassembled state and an assembled state of composite negative electrode body 108A.

(1) As the constituent members of the negative electrode assembly 108A, prepare: a solid electrolyte 112A (lithium ion conductive glass ceramic (LTAP) sheet, quadrilateral, two sheets) as a separator, metal lithium 115A (metal Li, quadrilateral) as a negative electrode layer , two sheets, one on each side of two copper foils 105A (consisting of a quadrangular plate-shaped portion and a strip-shaped terminal portion), contact holding layer 103A (polyolefin-based (PE resin) porous sheet , quadrilateral, one piece), cellulose diaphragm 117A (quadrilateral, two pieces) and spacer sheet 118A (EPDM, quadrilateral frame, two pieces). The lithium metal 115A is twice as thick as the lithium metal 115 of the first embodiment. One spacer sheet 118A is attached to each of the two solid electrolyte sheets 112A.

(2) On the first solid electrolyte sheet 112A shown on the lower side in FIG. , 1M LiPF ₆ ) was dropped onto the cellulose separator 117A and penetrated into the whole. A member (metal lithium 115A-copper foil 105A) formed by pasting copper foil 105A of a negative electrode current collector including a terminal portion on metal lithium 115A contacts the cellulose separator 117A with metal lithium 115A, and enters the spacer sheet 118A frame. The inner way is arranged on the cellulose membrane 117A. A polyolefin (PE resin)-based porous sheet is disposed on the copper foil 105A as the contact holding layer 103A. An organic electrolyte (EC:EMC=1:1, 1M LiPF ₆ ) was dropped onto the contact holding layer 103A and penetrated into the whole. The second metal lithium 115A-copper foil 105A is arranged on it so that the copper foil 105A is in contact with the polyolefin-based porous sheet 103A, and the second cellulose separator 117A is arranged on the metal lithium 115A. The organic electrolyte was dropped onto the second cellulose separator 117A and permeated into the whole, and it was confirmed that the cellulose separator 117A was in close contact with the metal lithium 115A.

(3) The second solid electrolyte 112A shown on the upper side in FIG. 19 is not biased so that the spacer pasted on the second solid electrolyte 112A overlaps the spacer pasted on the first solid electrolyte 112A. Relocate over the creation of (2). The two spacer sheets 118A are pasted together, and the adhesiveness of the spacer sheets 118A is used for airtight sealing so that outside air and the like do not enter. The constituent members inside the negative electrode assembly are pressed and fixed as a whole from the outside so that the solid electrolyte 112A and the lithium metal 115A are in contact with each other with good adhesion. In addition, part of the copper foil 105A (negative electrode current collector) pasted on the lithium metal 115A is exposed outside the solid electrolyte 112A as a negative electrode terminal.

(4) Apply epoxy-based adhesive 119A (two-component room-temperature curing type) thinly to the entire periphery of the solid electrolyte 112A so as to seal between two solid electrolytes 112A, and make the epoxy-based adhesive Adhesive 119A is cured. The two sheets of terminals are joined to the inner side of the negative electrode terminal by the brazing portion 104A, and protrude outside the negative electrode assembly 108A.

(Production of Air Pole)

Make the air electrode in the following order.

(1) Measure 80 mg of platinum-carrying carbon (Pt45.8%) as a catalyst for the oxygen reduction of the air pole, measure 20 mg of polyvinylidene fluoride (PVDF) as a binder (adhesive), and add 3 ml of N-methylpyrrolidone (NMP) to prepare a mixed solvent.

(2) For the mixed solvent, stir and disperse for 15 minutes with a stirrer (AR-100 manufactured by THINKY), stir and disperse for 60 minutes with an ultrasonic wave, and apply with a coater (K202 control coater manufactured by Matsuo Sangyo) On carbon cloth, and then placed on a heating plate and heated and dried at 110°C for 1 hour, an air electrode with a platinum loading capacity of about 0.25 mg/cm ² was produced.

(3) In the air electrode of (2), a platinum-supported carbon cloth is cut and produced. In the discharge test, two air electrodes were used.

(Preparation of aqueous electrolyte)

4.24 g of LiCl was dissolved in 500 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 assembly 108A.

(production of batteries)

The air electrode, the cellulose sheet dripped with the aqueous electrolyte, the negative electrode complex 108A, and the dripped cellulose sheet were accommodated in a perforated plastic case capable of accommodating the negative electrode assembly 108A. A cellulose sheet of an aqueous electrolyte and an air electrode were used to obtain the lithium-air battery of Example 2.

[Example 3]

The battery of Example 3 was produced in the following procedure.

(Production of Negative Electrode Complex)

In an atmosphere of Ar gas having an oxygen concentration of 1 ppm or less and a dew point of −76° C. dp, the negative electrode assembly of Example 3 (corresponding to a theoretical capacity of 336 mAh) was produced in the following procedure. Assembly of the constituent members was the same as that of the battery of Example 1 shown in FIG. 15 .

(1) Prepare a solid electrolyte (lithium ion conductive glass ceramic (LTAP) sheet, quadrangular, two sheets), metal lithium (quadrangular, two sheets, pasted on a copper foil (made of quadrangular) Both sides of the plate-shaped part and the strip-shaped terminal part), cellulose separators (square, two sheets), and gasket sheets (EPDM, four-sided frame, two sheets). The usage amount of metallic lithium is identical with embodiment 2. Paste a spacer on each of the two solid electrolytes.

(2) On the first solid electrolyte, arrange the cellulose separator in such a way that it enters the spacer frame, and drop the organic electrolyte (EC: EMC = 1:1, 1M LiPF ₆ ) onto the cellulose separator and infiltrate it. overall. The lithium metal is arranged on the cellulose diaphragm in such a way that it enters the spacer frame, and the second cellulose diaphragm is arranged on the lithium metal. The organic electrolyte was dropped onto the second cellulose separator and permeated into the whole, and it was confirmed that the cellulose separator was in close contact with lithium metal.

(3) Cover the product of (2) without shifting so that the spacer sheet attached to the second solid electrolyte overlaps with the spacer sheet attached to the first solid electrolyte. The two spacers are pasted together, and the adhesiveness of the spacers is used to seal so that outside air, etc. does not enter. The constituent members inside the negative electrode assembly were pressed and fixed as a whole from the outside so that the solid electrolyte and lithium metal were in contact with each other with good adhesion. In addition, a part of the copper foil (negative electrode current collector) pasted on the lithium metal was exposed outside the solid electrolyte.

(4) Apply an epoxy-based adhesive two-component room-temperature curing type) thinly to the entire periphery of the solid electrolyte in such a way as to seal the gap between the two solid electrolytes, and cure the epoxy-based adhesive .

(Production of Air Pole)

An air electrode was produced in the same manner as in Example 2.

(Preparation of aqueous electrolyte)

The aqueous electrolyte was prepared in the same manner as in Example 2.

(production of batteries)

The battery of Example 3 was fabricated by the same method as that of Example 2.

[Discharge test 2]

In the batteries of Examples 2 and 3 corresponding to a theoretical capacity of 336 mAh, at a temperature of 20° C., ALS608A manufactured by BAS Co., Ltd. was used to measure the theoretical capacity when discharged at a current density of 4 mA/cm ² corresponding to 0.05 C. discharge voltage. The measurement results of the discharge voltage are shown in FIG. 20 . As shown in Figure 20, both the batteries of Example 2 and Example 3 have shown a long-term stable discharge voltage, and the battery of Example 2 has further improved the discharge voltage and the discharge time of the battery of Example 3. the result of.

[Example 4]

The battery 101B of Example 4 was produced. FIG. 21 shows the structure of a battery 101B of Example 4. As shown in FIG. In addition, in FIG. 21 , each member is shown with a gap between each member for easy recognition, but actually each member is in contact with each other. The air electrode 109B is composed of an air electrode and a positive electrode current collector. In addition, although illustration is omitted, the opening of the air electrode is properly closed with a cover material such as rubber, elastic body, or adhesive.

(Production of Negative Electrode Complex)

In an atmosphere of Ar gas having an oxygen concentration of 1 ppm or less and a dew point of −76° C. dp, the negative electrode assembly 108B was produced in the following procedure.

(1) The solid electrolyte 112B (lithium ion conductive glass ceramic (LTAP) thin plate, quadrilateral, two sheets) for the separation layer is prepared. One of the two sheets of solid electrolyte 112B was divided in half vertically and horizontally to obtain four divided bodies. In the state of arrangement before the four divided bodies are divided, the cut parts are bonded using the rubber gasket 122B and the epoxy-based adhesive 123B, and the gaps between the divided bodies are sealed. The rubber gasket 122B and the epoxy-based adhesive 123B are pasted on one side of the solid electrolyte 112B in a cross shape.

(2) Prepare metal lithium 115B for the negative electrode layer (quadrilateral, two sheets, pasted on both sides of a copper foil (negative electrode current collector) 105B), polymer electrolyte 117B as a buffer layer (EC:EMC=1:1, 1M LiPF ₆ +PEO6%) and spacer sheets 118B (EPDM, four-frame, two sheets). The metallic lithium 115B is twice as thick as the metallic lithium 115 of Example 1. The outer dimensions of the spacer sheet 118B are set to be the same as those of the solid electrolyte 112B. A spacer sheet 118B is attached to the undivided solid electrolyte 112B and the solid electrolyte 112B to which four divided bodies have been bonded. When affixing the spacer sheet 118B to the solid electrolyte 112B to which the four divided bodies are bonded, it is pasted on the surface opposite to the surface on which the bonded rubber spacer 122B for the divided bodies is pasted.

(3) On one sheet of solid electrolyte 112B, polymer electrolyte 117B of a buffer layer is disposed so as to enter the frame of spacer sheet 118B. Lithium metal 115B and negative electrode current collector 105B are disposed on polymer electrolyte 117B of the buffer layer in such a manner as to enter the spacer sheet 118B frame. The second sheet of lithium metal 115B and the negative electrode current collector 105B are disposed thereon. A buffer layer polymer electrolyte 117B is placed and configured on lithium metal.

(4) Cover the solid electrolyte 112B produced in (1) on top of the product in (3), and paste them without shifting so that the spacers 118B pasted on the two solid electrolytes 112B overlap each other. , and use the adhesiveness of the gasket sheet 118B to seal it so that outside air and the like do not enter. The constituent members inside the negative electrode assembly 208B are pressed and fixed as a whole from the outside so that the solid electrolyte 112B and the metal lithium 115B are in contact with each other with good adhesion.

(5) Epoxy-based adhesive 119B (two-component room temperature curing type) is thinly applied to the entire periphery of the solid electrolyte 112B in a manner to seal and fix the gap between the two solid electrolytes 112B, and The epoxy-based adhesive 119B is cured.

(Production of Air Pole)

Measure 80 mg of platinum-supported carbon (Pt45.8%) as a catalyst for the oxygen reduction of the positive electrode, measure 20 mg of polyvinylidene fluoride (PVdF) as a binder (binder), and add 3 ml of N-methyl -2-pyrrolidone (NMP) to prepare a mixed solvent.

The mixed solvent was stirred and dispersed with a mixer (AR-100 manufactured by THINKY) for 15 minutes, stirred and dispersed with ultrasonic waves for 60 minutes, and coated on carbon cloth with a coater (K202 control coater manufactured by Matsuo Sangyo) After that, it was placed on a hot plate and heated and dried at 100°C for 1 hour to produce an air electrode with a platinum loading capacity of 0.2 mg/cm ² . As a current collector of the air electrode, aluminum foil was pasted on the air electrode.

(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 batteries)

Four air electrodes 109B, negative electrode assembly 108B, cellulose separator 107B as a water holding layer, and four air electrodes are sequentially accommodated in a perforated PP case (not shown) of a size capable of accommodating the negative electrode assembly. The pole 109B was injected with an aqueous electrolyte (2M LiCl aqueous solution) until the air pole 109B and the negative electrode assembly 108B were fully impregnated, and the case was closed to obtain the lithium-air battery of Example 4.

[Example 5]

The battery of the lithium-air battery of Example 5 was produced in the same manner as in Example 4, except that an undivided solid electrolyte was used as two solid electrolytes in the production of the negative electrode assembly.

[Example 6]

The battery of the lithium-air battery of Example 6 was produced in the same manner as in Example 4, except that the solid electrolyte was divided and bonded as follows in the production of the negative electrode assembly. One of the two solid electrolyte sheets was divided in half diagonally as shown in Table 2 to obtain four divided bodies. In the state of arrangement before dividing the four divided bodies, the cut part was bonded using a rubber gasket and an epoxy-based adhesive to seal the gap between the divided bodies. A rubber gasket and an epoxy-based adhesive are pasted diagonally on one side of the solid electrolyte.

[Example 7]

The battery of the lithium-air battery of Example 7 was produced in the same manner as in Example 4, except that the solid electrolyte was divided and bonded as follows in the production of the negative electrode assembly. One of the two sheets of solid electrolyte was divided into half horizontally and thirdly vertically as shown in Table 2 to obtain six divided bodies. Alternatively, one of the two solid electrolyte sheets may be divided into half in the vertical direction and third in the horizontal direction to obtain six divided bodies. In the state of arrangement before dividing the six divided bodies, the cut part was bonded using a rubber gasket and an epoxy-based adhesive to seal the gaps between the divided bodies. A rubber gasket and an epoxy-based adhesive were pasted linearly on one side of the solid electrolyte along the boundary of the segment.

[Discharge test 3]

In the batteries of Examples 4 and 5, the discharge voltage was measured at a temperature of 20° C. with an ALS608A manufactured by BAS Corporation when discharged at a current density of 4 mA/cm ² corresponding to 0.05 C relative to the theoretical capacity.

The measurement results of the discharge voltage are shown in Table 1 and FIG. 22 . As shown in Table 1, both the batteries of Example 4 and Example 5 showed a high discharge voltage stably, but the battery of Example 4 showed a high discharge capacity of 76.0% of the theoretical capacity. , as a result, it was confirmed that the discharged electric quantity was also high.

[Table 1] Comparison of the discharge electric quantity of embodiment 4 and embodiment 5

Theoretical capacity [Ah] Discharge capacity [Ah] Average voltage [V] Discharge power [Wh] Example 4 about 3 2.28 (76%) 2.00 4.56 Example 5 about 3 1.55 (49%) 2.25 3.49

[Discharge test 4]

In addition to Example 4 and Example 5, in the batteries of Example 6 and Example 7, ALS608A manufactured by BAS Corporation was also used to measure the theoretical capacity at a temperature of 20°C at a current density of 4mA/ Discharge voltage when cm ² is discharged.

Table 2 summarizes the measurement results of discharge test 3 and discharge test 4. As shown in Table 2, the batteries of Examples 4 to 7 all showed relatively high discharge voltages. Example 5 showed the highest average discharge voltage, but the separator of the composite negative electrode was damaged when the discharge capacity reached about 50% due to the reduction of the internal pressure in the reduction of the negative electrode layer as the discharge progressed. This is considered to be because a thick negative electrode layer twice the thickness of the negative electrode layer in Example 1 was used, and thus the effect of progress of discharge on the thinning of the negative electrode layer was largely exerted. In addition, the present inventors confirmed that when a thinner negative electrode layer having the same thickness as that of the negative electrode layer of Example 1 was used instead of a negative electrode layer twice as thick as that of Example 1 in the battery of Example 5, the separation layer The discharge can be performed to a depth of 90% or more without being damaged along with the progress of the discharge, and the discharge can be performed for a long time (data not shown).

On the other hand, the batteries of Example 4, Example 6, and Example 7 all moved stably at a relatively high discharge voltage. This is because, by dividing the separator layer, it is possible to cope with a decrease in internal pressure caused by thinning of the thick negative electrode layer as the discharge progresses. Although Example 5 has a high average discharge voltage, it is disadvantageous in terms of energy density because it cannot discharge for a long time if a thick negative electrode layer is used. From Table 2, it was confirmed that Example 4 and Example 6 are excellent in energy density, have no cracks in the separator, and are particularly suitable for long-term discharge. In view of these results, it can be said that as the number of divisions of the separator increases, although it is beneficial to long-term discharge, when the current density decreases with the decrease of the surface area of the separator, the discharge voltage decreases, and the electrolyte, etc. There is a high risk of leakage of the negative electrode complex, intrusion of air, and the like. Therefore, regarding the separation layer with a size of 2 inches on one side, the structure of Example 4 is considered to be the most preferable in consideration of realizing both the energy density and the resistance of the separation layer. However, when the size of the spacer layer becomes large, it may be preferable to increase the number of divisions without being limited thereto.

【Table 2】

[Example 8]

(Production of Negative Electrode Complex)

In an argon atmosphere with an oxygen concentration of 1 ppm or less and a dew point of −76° C. dp, the negative electrode assembly of Example 8 was produced in the following procedure. The negative electrode assembly was assembled in the same manner as the structure shown in FIG. 15 of the negative electrode assembly of the battery of Example 1.

(1) As the constituent members of the negative electrode complex, prepare: solid electrolyte (lithium ion conductive glass ceramic (LTAP) sheet, quadrilateral, two sheets), metal lithium (quadrilateral, two sheets, pasted on a copper foil (made of quadrangular Both sides of the plate-shaped part and the strip-shaped terminal part), cellulose separators (square, two sheets) and spacers (EPDM, four-sided frame, two sheets). Paste spacers on the two sheets of solid electrolyte.

(2) PEO was added to an organic electrolyte (EC:EMC=1:1, 1M LiPF ₆ ) to form a gel, and a gel electrolyte of PEO at a concentration of 5% by mass was prepared. Next, the cellulose separator is soaked in the gel electrolyte. The cellulose separator impregnated with the gel electrolyte was placed on a sheet of solid electrolyte so as to fit into the spacer frame. Lithium metal was arranged on the cellulose membrane in such a way that it entered the spacer frame, and the cellulose separator impregnated with gel polymer was arranged on the lithium metal by the same method as the second sheet.

(3) Cover the solid electrolyte produced in (1) on the top of the production in (2), paste the upper and lower gaskets so that they do not shift, and use the adhesiveness of the gaskets to seal so that external air and the like do not enter. The constituent members inside the negative electrode assembly were pressed and fixed as a whole from the outside so that the solid electrolyte and lithium metal were in contact with each other with good adhesion.

(4) Apply an epoxy-based adhesive (two-component room-temperature curing type) thinly on the entire periphery of the solid electrolyte in such a way as to seal the gap between the two solid electrolytes, and make the epoxy-based adhesive Adhesive curing.

(Production of Air Pole)

Measure 80 mg of platinum-supported carbon (Pt45.8%) as a catalyst for the oxygen reduction of the positive electrode, measure 20 mg of polyvinylidene fluoride (PVdF) as a binder (binder), and add 3 ml of N-methyl -2-pyrrolidone (NMP) to prepare a mixed solvent.

For the mixed solvent, stir and disperse for 15 minutes with a mixer (AR-100 manufactured by THINKY), and 60 minutes for stirring and disperse with an ultrasonic wave, and use a coater (K202 control coater manufactured by Matsuo Sangyo Co., Ltd.) Two pieces of carbon cloth with the same size as the components after depositing lithium metal were placed on a heating plate and heated and dried at 110°C for 1 hour to produce an air electrode with a platinum loading capacity of 0.5 mg/cm ² . The current collector of the air electrode was formed by extending the carbon cloth of the air electrode into 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 batteries)

The air electrode, the cellulose sheet dripped with the aqueous electrolyte, and the negative electrode complex are stored in a perforated plastic case of a size that can accommodate the negative electrode complex in order without deviation. About 500 μl of the dripping The cellulose sheet of the water-based electrolyte and the air electrode were obtained to obtain the battery of the lithium-air battery of Example 8.

[Example 9]

(Production of Negative Electrode Complex)

The negative electrode assembly of the battery of Example 9 was produced in the following procedure. The negative electrode assembly was assembled in the same manner as the structure shown in FIG. 15 of the negative electrode assembly of the battery of Example 1. In the battery of Example 9, components having the same material and size as those of the battery of Example 8 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) As the constituent members of the negative electrode complex, prepare: solid electrolyte (lithium-ion conductive glass ceramic (LTAP) sheet, quadrilateral, two), metal Li (quadrilateral, two, pasted on a copper foil (made of quadrilateral) Both sides of the plate-shaped part and the strip-shaped terminal part), cellulose separators (square, two sheets) and spacers (EPDM, four-sided frame, two sheets). Paste spacers on the two sheets of solid electrolyte.

(2) On a piece of solid electrolyte, arrange the cellulose diaphragm in such a way that it enters the gasket frame, and drop the organic electrolyte (EC:EMC=1:1, 1M LiPF ₆ ) onto the cellulose diaphragm and penetrate into the whole . The metal Li was placed on the cellulose separator in such a way that it entered the spacer frame, and the second cellulose separator was placed on the metal Li. The organic electrolyte is dripped onto the second cellulose separator and permeates the whole.

(3) Cover the solid electrolyte produced in (1) on the top of the production in (2), paste the spacers attached to the two solid electrolytes in such a way that they do not deviate from each other, and use the adhesion of the spacers to It is airtight so that outside air and the like do not enter. The constituent members inside the negative electrode assembly are pressed and fixed from the outside as a whole so that the solid electrolyte and metal Li are in contact with each other with good adhesion.

(4) Apply an epoxy-based adhesive (two-component room-temperature curing type) thinly on the entire periphery of the solid electrolyte in such a way as to seal the gap between the two solid electrolytes, and make the epoxy-based adhesive Adhesive curing.

Preparation of an air electrode, preparation of an aqueous electrolyte, and preparation of a battery were carried out in the same manner as in Example 8.

[Discharge test 5]

In the batteries of Examples 8 and 9, the discharge voltage when discharged at 4 mA/cm ² (a discharge rate of about 0.1 C) for 7 hours was measured with an electrochemical analyzer ALS608A manufactured by BAS Corporation. Here, 1C refers to a constant current discharge of a battery having a nominal capacity, and a current value exactly after 1 hour of discharge. The measurement results of the discharge voltage are shown in FIG. 23 and Table 3. As shown in FIG. 23 and Table 3, both the battery of Example 8 and the battery of Example 9 showed higher discharge voltages at all measurement times. The average discharge voltage was 1.89 V in the battery of Example 8, and 1.33 V in the battery of Example 9. Compared with the battery of Example 9, the discharge voltage of the battery of Example 8 was greatly improved.

[Table 3] Results of discharge test 5 (4mA/cm ² )

[Example 10]

(Production of Negative Electrode Complex)

In an argon atmosphere with an oxygen concentration of 1 ppm or less and a dew point of −76° C. dp, the negative electrode assembly of Example 10 was produced in the following procedure. The negative electrode assembly was assembled in the same manner as the structure shown in FIG. 15 of the negative electrode assembly of the battery of Example 1. In the battery of Example 10, components having the same material and size as those of the battery of Example 8 were used except that a powder-containing gel electrolyte was used as a buffer layer instead of the cellulose separator impregnated with the gel electrolyte.

(1) As the constituent members of the negative electrode complex, prepare: solid electrolyte (lithium ion conductive glass ceramic (LTAP) sheet, quadrilateral, two sheets), metal lithium (quadrilateral, two sheets, pasted on a copper foil (made of quadrangular The plate-shaped part and the strip-shaped terminal part constitute) both sides) and spacers (EPDM, four-frame, two sheets). Paste spacers on the two sheets of solid electrolyte.

(2) Add PEO with an average particle diameter of 5 μm to 5% by mass of PEO prepared by adding PEO to an organic electrolyte (organic electrolyte: EC:EMC=1:1, 1M LiPF ₆ ) to make a gel. The fine powder residue of polypropylene was used to prepare a gel electrolyte containing PEO at a concentration of 4% by mass of 1% by mass of fine powder of polypropylene. The gel electrolyte mixed with the fine powder slag of polypropylene was placed on a sheet of solid electrolyte so as to enter the spacer frame, and adjusted with a spatula or the like to make the surface uniform. Lithium metal is placed on it and arranged so as to enter the spacer frame, and the gel electrolyte mixed with fine powder slag of polypropylene is placed on the lithium metal and adjusted so that the surface becomes uniform.

(3) Cover the solid electrolyte produced in (1) on the top of the production in (2), paste the upper and lower gaskets so that they do not shift, and use the adhesiveness of the gaskets to seal so that external air and the like do not enter. The internal constituent members of the negative electrode assembly are pressed and fixed from the outside as a whole so that the solid electrolyte and lithium metal are in good contact with each other through the gel dielectric.

(4) Apply an epoxy-based adhesive (two-component room-temperature curing type) thinly on the entire periphery of the solid electrolyte in such a way as to seal the gap between the two solid electrolytes, and make the epoxy-based adhesive Adhesive curing.

(Production of Air Pole)

Measure 80 mg of platinum-supported carbon (Pt45.8%) as a catalyst for the oxygen reduction of the positive electrode, measure 20 mg of polyvinylidene fluoride (PVdF) as a binder (binder), and add 3 ml of N-methyl -2-pyrrolidone (NMP) to prepare a mixed solvent.

For the mixed solvent, stir and disperse for 15 minutes with a mixer (AR-100 manufactured by THINKY), and 60 minutes for stirring and disperse with an ultrasonic wave, and use a coater (K202 control coater manufactured by Matsuo Sangyo Co., Ltd.) Two pieces of carbon cloth with the same size as the components after depositing lithium metal were placed on a heating plate and heated and dried at 110°C for 1 hour to produce an air electrode with a platinum loading capacity of 0.5 mg/cm ² . The current collector of the air electrode was formed by extending the carbon cloth of the air electrode into 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.

A battery was fabricated in the same manner as in Example 8.

[Discharge test 6]

The discharge voltage of the battery of Example 10 was measured under the same conditions as in the discharge test 5. The results are shown in Table 4. The battery of Example 10 showed higher initial discharge voltage and average discharge voltage.

[Table 4] Results of discharge test 6 (4mA/cm ² )

Claims (21)

1. A lithium-air battery, wherein the lithium-air battery includes a negative electrode composite and an air pole, The negative electrode complex includes: A plate-like or wire-like negative electrode current collector; two negative electrode layers in a plate shape formed of metallic lithium, an alloy mainly composed of lithium, or a compound mainly composed of lithium, and a part of the negative electrode current collector is sandwiched therebetween; two separator layers in a plate shape sandwiching all of the two negative electrode layers therebetween and having lithium ion conductivity; and a gasket, which is disposed between the two isolation layers so that the two negative electrode layers are surrounded and seals the space between the two isolation layers; The air pole includes: an air electrode layer containing a conductive material opposite at least one of the two separator layers; and A plate-shaped or linear air electrode current collector is electrically connected to the air electrode layer. 2. The lithium air battery according to claim 1, wherein, The negative electrode current collector is composed of a plate-shaped first negative electrode current collector and a plate-shaped second negative electrode current collector, and there is swelling between the first negative electrode current collector and the second negative electrode current collector. The contact holding layer has lithium ion conductivity. 3. The lithium-air battery according to claim 1 or 2, wherein, One or both of the two separator layers are respectively divided by the first dividing line and the second dividing line in the plane adjacent to the negative electrode layer, and the divided body formed by the division is arranged on the In the state of the position, the gap between the split bodies is sealed by the sealing member. 4. A negative electrode composite of a lithium-air battery, wherein the negative electrode composite of the lithium-air battery comprises: A plate-like or wire-like negative electrode current collector; two negative electrode layers in a plate shape formed of metallic lithium, an alloy mainly composed of lithium, or a compound mainly composed of lithium, and a part of the negative electrode current collector is sandwiched therebetween; two separator layers in a plate shape sandwiching all of the two negative electrode layers therebetween and having lithium ion conductivity; and The spacer is arranged between the two isolation layers so as to surround the two negative electrode layers and seal the space between the two isolation layers. 5. The negative electrode complex of lithium-air battery according to claim 4, wherein, The negative electrode composite of this lithium-air battery further has a peripheral sealing member for hermetically sealing between the two separator layers on the outer peripheral portions of the two separator layers. 6. The negative electrode composite according to claim 4 or 5, wherein, The gasket is rubber or elastomer. 7. The negative electrode composite according to claim 6, wherein, The rubber or elastomer is a rubber or elastomer formed by ethylene-propylene-diene copolymerization, or a fluorine-based rubber or elastomer. 8. The negative electrode composite according to claim 4, wherein, The negative electrode composite further has a buffer layer between the negative electrode layer and the separator layer. 9. The negative electrode composite according to claim 8, wherein, The buffer layer is a gel electrolyte or a separator containing a gel electrolyte. 10. The negative electrode composite according to claim 9, wherein, The gel electrolyte contains a powder that is insoluble in an organic electrolyte. 11. The negative electrode composite according to claim 10, wherein, The powder is resin powder. 12. The negative electrode composite according to claim 11, wherein, The resin powder is polypropylene, polyethylene or a mixture of these substances. 13. The negative electrode complex of lithium air battery according to claim 4, wherein, The negative electrode current collector is composed of a plate-shaped first negative electrode current collector and a plate-shaped second negative electrode current collector, and there is swelling between the first negative electrode current collector and the second negative electrode current collector. The contact holding layer has lithium ion conductivity. 14. The negative electrode complex of lithium air battery according to claim 13, wherein, The contact holding layer is formed of a resin or rubber porous sheet, a gel-like polymer electrolyte, or a porous sheet containing a gel-like polymer electrolyte. 15. The negative electrode complex of the lithium-air battery according to claim 13 or 14, wherein, The first negative electrode current collector and the second negative electrode current collector are integrally formed, and have a negative electrode current collector folded portion, and the negative electrode current collector folded portion is used to connect two negative electrodes adjacent to the contact holding layer The flat part of the current collector. 16. The negative electrode complex of lithium air battery according to claim 13, wherein, One or both of the first negative electrode current collector and the second negative electrode current collector are connected to the negative electrode terminal portion drawn outside the spacer, or integrally formed with the negative electrode terminal portion. 17. The negative electrode complex of lithium air battery according to claim 13, wherein, The two negative electrode layers are integrally formed, and have a negative electrode layer turn-back portion, and the negative electrode layer turn-back portion is used to connect the two negative electrode layer planar portions adjacent to the separator. 18. The negative electrode complex of lithium air battery according to claim 13, wherein, One or both of the two separator layers are respectively divided by the first dividing line and the second dividing line in the plane adjacent to the negative electrode layer, and the divided body formed by the division is arranged on the In the state of the position, the gap between the split bodies is sealed by the sealing member. 19. The negative electrode complex of lithium air battery according to claim 18, wherein, In a state where the separation layer divided by the first dividing line and the second dividing line is divided by one or more in-plane dividing lines, and the divided body formed by the division is in the state before division, the The gaps between the divided bodies are sealed by the sealing member. 20. The negative electrode complex of lithium air battery according to claim 18 or 19, wherein, The sealing member is a rubber or elastic gasket, an adhesive, or a combination of these. 21. A lithium-air battery, wherein the lithium-air battery comprises an air pole and the negative electrode composite according to any one of claims 4 to 20, The air pole includes: an air electrode layer containing a conductive material opposite at least one of the two separator layers; and A plate-shaped or linear air electrode current collector is electrically connected to the air electrode layer.