JP2016028380A - All-solid air battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an all-solid air battery which enables the suppression of the reduction in ion conductivity owing to an interface resistance at a boundary of an electrode layer and a solid electrolytic layer and therefore enables a large-current charge and discharge.SOLUTION: An all-solid air battery (1) comprises: a negative electrode (B) having a negative electrode material (4) capable of occluding and releasing metal ions; a positive electrode (A) using oxygen as a positive electrode active material, including means for introducing air, and having a positive electrode material(2) including a catalyst serving to reduce oxygen; and a solid electrolytic layer (C) interposed between the negative and positive electrodes, and including a solid electrolyte (3) having metal ion conductivity. The negative and positive electrode materials include the solid electrolyte, and are integrated with the solid electrolytic layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an all-solid-state air battery.

  In recent years, with the development of portable devices such as personal computers and mobile phones, the demand for batteries as power sources has been greatly expanded. Aiming at realization of a battery with a larger capacity, research on a lithium-air battery having a high energy density by using oxygen in the air as a positive electrode active material is underway. Lithium-air batteries do not need to be filled with a positive electrode active material, so it is possible to fill a large amount of metallic lithium as a negative electrode active material in the battery, and it has been reported that a very large discharge capacity is exhibited. .

Such a lithium-air battery includes, for example, a positive electrode layer containing a conductive material, a catalyst, and a binder, a positive electrode current collector that collects current from the positive electrode layer, a negative electrode layer made of a metal or an alloy, and a negative electrode A negative electrode current collector that performs current collection of the layer, and an electrolyte interposed between the positive electrode layer and the negative electrode layer. And it is thought that the following charge-discharge reaction advances in a lithium air battery.
[During discharge]
Negative electrode: Li → Li ⁺ + e ⁻
Positive electrode: 2Li ⁺ + O ₂ + 2e ⁻ → Li ₂ O ₂
[When charging]
Negative electrode: Li ⁺ + e ⁻ → Li
Positive electrode: Li ₂ O ₂ → 2Li ⁺ + O ₂ + 2e ⁻

  Conventionally, an electrolytic solution in which a supporting electrolyte salt is dissolved in an organic solvent has been used as an electrolyte of a battery. An electrolytic solution using an organic solvent as a medium exhibits high ionic conductivity.

  However, a lithium-air battery using an electrolytic solution needs to be improved in terms of structure and material for the installation of a safety device that suppresses the temperature rise at the time of a short circuit and the prevention of a short circuit. In addition, since the organic solvent is volatile, it is considered that there is a problem in stability in long-term operation in a lithium air battery having a structure that takes air into the battery. That is, in the long-term operation of the lithium-air battery, the electrolyte solution may volatilize from the positive electrode. As the electrolytic solution volatilizes, it is expected that the battery performance of the lithium-air battery is increased and the battery performance is significantly reduced.

  On the other hand, an all-solid-state air battery in which the electrolytic solution is changed to a solid electrolyte does not use an organic solvent in the battery. Therefore, the risk of combustion (ignition) is low, the safety device can be simplified, and the manufacturing cost and productivity are excellent. Further, in the all solid-state air battery, there is no possibility that the organic solvent volatilizes from the positive electrode. Accordingly, it is possible to prevent a decrease in battery performance due to volatilization of the organic solvent.

  However, a battery using a solid electrolyte has a higher cell resistance than a battery using an electrolytic solution. The reason why the cell resistance of the battery using the solid electrolyte is high is that the resistance at the interface between the solid electrolyte and the positive electrode layer and the negative electrode layer is larger than the resistance at the interface between the electrolyte solution, the positive electrode layer and the negative electrode layer. That is, in the case of an all-solid-state air battery, it is necessary to eliminate this interfacial resistance problem in order to charge and discharge a large current.

  Patent Document 1 discloses a lithium-air battery including a negative electrode, a positive electrode including a catalyst for oxygen reduction and a first solid electrolyte layer, and a second solid electrolyte layer disposed between the negative electrode and the positive electrode. Patent Document 1 also discloses that the first solid electrolyte layer and the second solid electrolyte layer are continuous without being physically separated. That is, in the invention described in Patent Document 1, the interface resistance at the boundary between the positive electrode and the second solid electrolyte layer is reduced by the first and second solid electrolyte layers being continuous without being physically separated. However, since an interface is formed at the boundary between the second solid electrolyte layer and the negative electrode, the invention described in Patent Document 1 still has a problem of interface resistance. Therefore, the lithium-air battery disclosed in Patent Document 1 cannot be expected to be charged / discharged with a large current.

Moreover, since the lithium air battery described in Patent Document 1 uses an electrolytic solution using an organic solvent as a negative electrode protective layer, there is a problem in long-term operation such as volatilization of the electrolytic solution.
Furthermore, since the lithium air battery described in Patent Document 1 includes an electrolyte composed of a polymer and an aqueous solution in the positive electrode and uses an electrolytic solution using an organic solvent as a negative electrode protective layer, the positive electrode structure and the negative electrode structure There is also a problem that high integration cannot be achieved by stacking and integrally firing the layers.

JP 2011-96586 A

  Therefore, the present invention has been made in view of the above circumstances, and its object is to suppress a decrease in ionic conductivity due to interface resistance at the boundary between the electrode layer and the solid electrolyte layer, and An object of the present invention is to provide an all-solid-state air battery that can be charged and discharged.

  In order to solve the above problems, an all-solid-state air battery of the present invention includes a negative electrode having a negative electrode material capable of occluding and releasing metal ions, means for introducing air using oxygen as a positive electrode active material, and reduces oxygen. An all-solid-state air battery having a positive electrode having a positive electrode material including a catalyst and a solid electrolyte layer made of a solid electrolyte that conducts metal ions interposed between the negative electrode and the positive electrode, wherein the negative electrode material and the positive electrode material are solid electrolytes And is integrated with the solid electrolyte layer.

  The all-solid-state air battery of the present invention employs a configuration in which the positive electrode material constituting the positive electrode and the negative electrode material constituting the negative electrode comprise the same material as the solid electrolyte constituting the solid electrolyte layer interposed between the positive electrode and the negative electrode. That is, in the all-solid-state air battery of the present invention, one solid electrolyte is connected from the positive electrode to the negative electrode via the solid electrolyte layer to form a solid electrolyte network. Here, the “solid electrolyte network” means that a large number of powder particles constituting the solid electrolyte are three-dimensionally connected by sintering to form an ionic conductor.

By adopting an integrated configuration of the same solid electrolyte, the all-solid-state air battery of the present invention is capable of conducting ionic conduction due to interface resistance at the boundary between the positive electrode and the solid electrolyte layer and at the boundary between the solid electrolyte layer and the negative electrode. A decrease in rate can be suppressed. That is, the all-solid-state air battery of the present invention can prevent the battery performance from being lowered due to the interface resistance.
Further, the positive electrode material constituting the positive electrode and the negative electrode material constituting the negative electrode are provided with the same material as the solid electrolyte constituting the solid electrolyte layer interposed between the positive electrode and the negative electrode, thereby laminating each member. Therefore, the structure is suitable for integration.

It is the schematic which showed typically the laminated body 100 of the all-solid-state air battery 1 regarding 1st Embodiment. It is the schematic which showed the positive electrode green sheet 20 typically regarding 2nd Embodiment. It is the schematic which showed the solid electrolyte green sheet 30 typically regarding 2nd Embodiment. It is the schematic which showed the cell green sheet 50 typically regarding 2nd Embodiment. It is the schematic which showed the laminated body green sheet 70 typically regarding 2nd Embodiment. It is the schematic which showed typically the all-solid-state air battery 11 regarding 2nd Embodiment. It is a figure which shows the result of a test example. It is the figure which showed typically the cell cross section of the test example.

(First embodiment)
Hereinafter, description will be given with reference to FIG. The all-solid-state air battery 1 of the first embodiment has a positive electrode A, a negative electrode B, and a solid electrolyte layer C. The positive electrode A includes a positive electrode material 2 that includes air introduction means for advancing a battery reaction using oxygen as an active material, and includes a catalyst that reduces oxygen. The negative electrode B has a negative electrode material 4 capable of occluding and releasing metal ions. The solid electrolyte layer C functions as a transmission path through which metal ions move between the positive electrode A and the negative electrode B. The laminate 100 includes a positive electrode part 200 made of the positive electrode material 2, a solid electrolyte part 300 made of the solid electrolyte 3, and a negative electrode part 400 made of the negative electrode material 4. The metal ions are ions of one or more metals selected from the group consisting of Li, Na, K, Mg, Ca, Fe, Zn, and Al. Hereinafter, the metal ions will be described by taking Li ions as an example, but are not limited thereto.

  The external shape of the all-solid-state air battery 1 of the present embodiment is not particularly limited as long as it is a form in which air (oxygen) can be brought into contact with the positive electrode A. As a form which can make air contact the positive electrode A, what has the shape which has an oxygen intake port can be illustrated. As an outer shape, for example, a cylindrical shape, a square shape, a button shape, a coin shape, a flat shape, or the like can be used. Moreover, the all-solid-state air battery 1 of this embodiment may be a primary battery or a secondary battery.

[Solid electrolyte layer C]
The solid electrolyte layer C is interposed between the positive electrode A and the negative electrode B, and is composed of the solid electrolyte 3 that conducts (or can conduct) metal ions. In particular, it is desirable that the solid electrolyte 3 is made of a material having no electron conductivity and high metal ion conductivity. The solid electrolyte 3 is preferably an inorganic material that can be fired at a high temperature in an air atmosphere.

  The inorganic solid electrolyte may be a crystal, glass, a mixture or a composite of both. The inorganic solid electrolyte may be sulfide-based or oxide-based. More desirably, an oxide system having excellent atmospheric stability and suitable for high-temperature firing is preferable.

Such an oxide-based inorganic solid electrolyte has a crystal structure selected from the group consisting of perovskite type, NASICON type, LISICON type, thio-LISICON type, γ-Li ₃ PO ₄ type, garnet type, and LIPON type. It is desirable to include at least one or more inorganic solid electrolyte materials.

Examples of the perovskite oxide include oxides represented by Li _x La _1-x TiO ₃ (Li—La—Ti—O-based perovskite oxide).

As the NASICON type oxide, for example, Li _{a Xb} Y _{cP d} O _e (X is at least one selected from the group consisting of B, Al, Ga, In, C, Si, Ge, Sn, Sb and Se). Y is at least one selected from the group consisting of Ti, Zr, Ge, In, Ga, Sn and Al, and 0.5 <a <5.0, 0 ≦ b <2. 98, 0.5 ≦ c <3.0, 0.02 <d ≦ 3.0, 2.0 <b + d <4.0, and 3.0 <e ≦ 12.0. Oxides. In particular, in the above formula, an oxide where X = Al and Y = Ti (Li-Al-Ti-PO-based NASICON type oxide), and X = Al, Y = Ge or X = Ge, Y = An oxide that is Al (Li—Al—Ge—Ti—O-based NASICON-type oxide) is preferable. _{Then, Li 1.3 Al 0.3 Ti 1.7 (} PO 4) is a Li-Al-Ti-PO based NASICON type oxide 3 (LATP) is more preferable.

As the LISICON-type oxide, thio-LiSICON-type oxide, or γ-Li ₃ PO ₄ -type oxide, for example, Li ₄ XO ₄ -Li ₃ YO ₄ (X is at least one selected from Si, Ge, and Ti) Y is at least one selected from P, As and V), Li ₄ XO ₄ -Li ₂ AO ₄ (X is at least one selected from Si, Ge and Ti. A Is at least one selected from Mo and S), Li ₄ XO ₄ —Li ₂ ZO ₂ (X is at least one selected from Si, Ge, and Ti. Z is from Al, Ga and Cr) And at least one selected from Li ₄ XO ₄ -Li ₂ BXO ₄ (X is at least one selected from Si, Ge, and Ti. B is selected from Ca and Zn). Li ₃ DO ₃ -Li ₃ YO ₄ (D is B, Y is at least one selected from P, As, and V), and the like. In particular, Li _3.25 Ge _0.25 P _0.75 S ₄ , Li ₄ SiO ₄ —Li ₃ PO ₄ , Li ₃ BO ₃ —Li ₃ PO _{4 and the} like are preferable.

The garnet-type oxide, and examples thereof _include an oxide represented by _{Li 3 + x A y G z} M 2-v B v O 12. Here, A, G, M and B are metal cations. A is preferably an alkaline earth metal cation such as Ca, Sr, Ba and Mg, or a transition metal cation such as Zn. G is preferably a transition metal cation such as La, Y, Pr, Nd, Sm, Lu, or Eu. Examples of M include transition metal cations such as Zr, Nb, Ta, Bi, Te, and Sb. Among these, Zr is preferable. B is preferably In, for example. It is preferable to satisfy 0 ≦ x ≦ 5, and it is more preferable to satisfy 4 ≦ x ≦ 5. It is preferable to satisfy 0 ≦ y ≦ 3, and it is more preferable to satisfy 0 ≦ y ≦ 2. It is preferable to satisfy 0 ≦ z ≦ 3, and it is more preferable to satisfy 1 ≦ z ≦ 3. It is preferable to satisfy 0 ≦ v ≦ 2, and it is more preferable to satisfy 0 ≦ v ≦ 1. O may be partially or completely exchanged with a divalent anion and / or a trivalent anion, for example, N ³⁻ . As the garnet-type oxide, Li—La—Zr—O-based oxides such as Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) are preferable.

Examples of the LiPON type oxide include Li _2.88 PO _3.73 N _0.14 and Li _3.0 PO _2.0 N _1.2 .

Examples of the sulfide-based inorganic solid electrolyte include Li ₂ S—P ₂ S ₅ , Li ₂ S—P ₂ S ₅ —LiI, Li ₂ S—P ₂ S ₅ —Li ₂ O, and Li ₂ S—P _{2. S 5 -Li 2 O-LiI,} Li 2 S-SiS 2, Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -LiBr, Li 2 S-SiS 2 -LiCl, Li 2 S-SiS 2 - _{B 2 S 3 -LiI, Li 2} S-SiS 2 -P 2 S 5 -LiI, Li 2 S-B 2 S 3, Li 2 S-P 2 S 5 -Z m S n (m, n is a positive Z is at least one selected from Ge, Zn, and Ga.), Li ₂ S—GeS ₂ , Li ₂ S—SiS ₂ —Li ₃ PO ₄ , Li ₂ S—SiS ₂ —Li _x MO _{y (x, y} is a positive number .M is, P, Si, Ge B, and at least one Al, Ga, selected from an In.) And the like.

[Positive electrode A]
The positive electrode A includes a portion made of a positive electrode material 2 including a catalyst, a solid electrolyte, and, if necessary, a conductive material, and a positive electrode current collector. The positive electrode material 2 uses a solid electrolyte as a base material and has holes into which air can be introduced. A catalyst and a conductive material are employed on the inner surface of the hole as necessary. The solid electrolyte is the same as the solid electrolyte 3 selected as the solid electrolyte layer C described above. “The positive electrode material 2 has a solid electrolyte as a base material” means that the solid electrolyte is a component having the highest content ratio in the positive electrode material 2. The base material also functions as a base material for holding (supporting) the catalyst.

  The catalyst is a catalyst that promotes the reaction of oxygen, which is a positive electrode active material, in the positive electrode A. The positive electrode active material uses oxygen in the air. The catalyst is one or more selected from the group consisting of silver, platinum, iridium oxide, ruthenium oxide, manganese oxide, cobalt oxide, nickel oxide, iron oxide, copper oxide, and metal phthalocyanines. Can be illustrated.

  The conductive material is not particularly limited as long as it has conductivity. The conductive material is used as necessary. The conductive material is desirably a material having the necessary stability under the atmosphere in the battery and suitable for high-temperature firing. For example, it is preferable to use a metal or alloy having high oxidation resistance. Here, the metal or alloy having high oxidation resistance is preferably silver, palladium, gold, platinum, aluminum, nickel or the like if it is specifically a metal. If it is an alloy, it is preferable that it is an alloy which consists of 2 or more types of metals chosen from silver, palladium, gold, platinum, copper, aluminum, and nickel. These oxides are also desirable.

  Any positive electrode current collector may be used as long as it has electrical conductivity. By the way, the positive electrode A needs a means for introducing air into the positive electrode material 2. Therefore, it is desirable that the positive electrode current collector be permeable to oxygen (having a structure capable of transmitting oxygen). For example, the positive electrode current collector is preferably a porous material composed of a metal such as stainless steel, nickel, aluminum, or copper, or a net / punched metal. Moreover, when using a porous material etc., it is desirable to employ | adopt the form with which the hole was filled with the electrically conductive material, the catalyst, etc.

[Negative electrode B]
The negative electrode B includes a negative electrode material 4 including a negative electrode active material capable of occluding and releasing metal ions and a negative electrode current collector. The negative electrode material 4 includes a negative electrode active material, a solid electrolyte, and a conductive material as necessary. As a negative electrode collector, copper, nickel, etc. can be made into forms, such as a net | network, a punched metal, foam metal, plate shape, foil shape, for example. A battery casing can also be used as the negative electrode current collector.

  Negative electrode active materials include metallic lithium, lithium alloys, metal materials that can store and release lithium, and alloy materials that can store and release lithium (not only alloys consisting of metals but also alloys of metals and metalloids). The structure consists of a solid solution, a eutectic (eutectic mixture), an intermetallic compound or a compound in which two or more of them coexist), and a compound capable of inserting and extracting lithium. One or more materials selected from the group. However, as will be described later, in the present invention, since the positive electrode part 200, the solid electrolyte part 300, and the negative electrode part 400 are formed by integral firing, the negative electrode active material is preferably a material suitable for high-temperature firing.

Metal elements and metalloid elements that can constitute metal materials and alloy materials include tin (Sn), lead (Pb), aluminum (Al), indium (In), silicon (Si), zinc (Zn), and antimony (Sb). ), Bismuth (Bi), cadmium (Cd), magnesium (Mg), boron (B), gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), zirconium (Zr), yttrium (Y ) And hafnium (Hf). Examples of these alloy materials or compounds include those represented by the chemical formula Ma _f Mb _g Li _h or the chemical formula Ma _s Mc _t Md _u . In these chemical formulas, Ma represents at least one of a metal element and a metalloid element capable of forming an alloy with lithium, Mb represents at least one of a metal element and a metalloid element other than lithium and Ma, Mc represents at least one of non-metallic elements, and Md represents at least one of metallic elements and metalloid elements other than Ma. Further, f> 0, g ≧ 0, h ≧ 0, s> 0, t> 0, u ≧ 0.

  Among them, the negative electrode material 4 is preferably a simple substance, alloy or compound of a group 4B metal element or metalloid element in the short-period type periodic table, particularly preferably silicon (Si) or tin (Sn), or an alloy thereof. A compound. These may be crystalline or amorphous.

Examples of the material capable of inserting and extracting lithium further include oxides, sulfides, and other metal compounds such as lithium nitrides such as LiN ₃ . Examples of the oxide include MnO ₂ , V ₂ O ₅ , V ₆ O ₁₃ , NiS, and MoS. In addition, examples of the oxide that has a relatively low potential and can occlude and release lithium include iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, titanium oxide, and tin oxide. Examples of the sulfide include NiS and MoS.

  The solid electrolyte contained in the negative electrode material 4 is the same as the solid electrolyte 3 used in the solid electrolyte layer C.

  As the conductive material, those exemplified in the column of the positive electrode A can be used. The conductive material is used as necessary.

  The negative electrode current collector has only to have electrical conductivity. For example, copper, stainless steel, nickel, etc. can be mentioned. Examples of the shape of the negative electrode current collector include a foil shape, a plate shape, and a mesh (grid) shape.

[Production of First Embodiment]
The all-solid-state air battery 1 of this embodiment is manufactured as follows as an example.
For the production of the solid electrolyte layer C, first, a solid electrolyte powder and a binder are prepared, and a solid electrolyte slurry is prepared. Next, a solid electrolyte green sheet is produced from the solid electrolyte slurry.

  Here, the green sheet refers to an unsintered body such as a crystal powder formed into a thin plate shape. Specifically, a mixed slurry of crystal powder, a conductive material, a binder, a solvent, and the like is subjected to a doctor blade, a calendar method, A thin plate formed by a coating method such as spin coating or dip coating, a printing method such as ink jet and offset, a die coater method, a spray method or the like.

  The binder has a function of connecting the constituent elements contained in the solid electrolyte. Although it does not specifically limit as a binder, A thermoplastic resin, a thermosetting resin, etc. are mentioned. For example, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene butadiene rubber, tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE resin) , Polychlorotrifluoroethylene (PCTFE), vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrif Examples include olefin copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, and ethylene-acrylic acid copolymer. . These materials may be used alone or in combination.

  The solid electrolyte layer C of the present embodiment is desirably provided with a hole for introducing the negative electrode material 4 into a part thereof. That is, the solid electrolyte green sheet is divided into a portion that becomes the solid electrolyte portion 300 and a portion that becomes the negative electrode portion 400 after the subsequent integral firing. The negative electrode part 400 is provided at the other end opposite to one end of the solid electrolyte part 300 on which a positive electrode green sheet is laminated later.

  It is desirable to include the pore former and the negative electrode material 4 in the portion that becomes the negative electrode portion 400 of the solid electrolyte green sheet. As will be described in more detail later, after the positive electrode green sheet and the solid electrolyte green sheet are integrally fired, the portion that becomes the negative electrode portion 400 is vacated by the action of the pore former. The negative electrode part 400 is manufactured by introducing liquefied metallic lithium into the pores at a predetermined pressure or by depositing lithium (negative electrode material 4) through a solid electrolyte.

  The pore former forms pores in the portion that becomes the negative electrode portion 400. That is, the pore former is for forming a hole for introducing the negative electrode active material. Therefore, it is desirable that the pore former is a material that can be vaporized by firing to form pores. For example, the pore former is made of theobromine, graphite, wheat flour, starch, phenol resin, polymethyl methacrylate, polyethylene, polyethylene terephthalate, foamed resin (acrylonitrile plastic balloon, etc.), etc. Can be mentioned. The pore former is preferably used together with a conductive material. Thereby, the negative electrode B can form pores provided with the conductive material after firing.

  As the manufacture of the positive electrode part 200, first, a catalyst powder, a pore former powder, a conductive material powder, and a binder are prepared, and a positive electrode slurry is prepared. Next, a positive electrode green sheet is produced from this positive electrode slurry. The pore former used here is for providing holes for introducing oxygen into the positive electrode material. That is, a material capable of forming pores by being vaporized by firing is desired. It is desirable to use the same material as the pore former described above as the pore former.

  The produced solid electrolyte green sheet and positive electrode green sheet are laminated to form a laminate 100. At this time, the positive electrode green sheet is laminated on one end of the solid electrolyte sheet opposite to the other end of the solid electrolyte green sheet containing the pore former. And the produced laminated body 100 is integrally baked. As described above, the solid electrolyte green sheet and the positive electrode green sheet are combined and integrated. That is, the positive electrode material 2 and the solid electrolyte 3 are combined and integrated.

  After the integral firing of the positive electrode material 2 and the solid electrolyte 3, the other end of the solid electrolyte layer C containing the pore former forms a void. The negative electrode material 4 is preferably formed by introducing liquefied metallic lithium into the pores at a predetermined pressure. It is also desirable that the negative electrode material 4 be formed by electrodepositing metallic lithium in the pores by charging and discharging.

  After introducing the negative electrode material 4 into the holes formed at the other end of the solid electrolyte layer C, the laminate 100 forms the positive electrode part 200, the solid electrolyte part 300, and the negative electrode part 400. The positive electrode part 200 uses the same solid electrolyte as the solid electrolyte part 300 as a base material. Therefore, it is considered that the decrease in ionic conductivity due to the interface resistance at the boundary between the positive electrode part 200 and the solid electrolyte part 300 after the integral firing is suppressed.

  Thus, the fired laminated body 100 forms a matrix structure using the same solid electrolyte as a base material from the positive electrode part 200 through the solid electrolyte part 300 to the negative electrode part 400. Therefore, this embodiment can suppress a decrease in ionic conductivity due to the interface resistance at the boundary of each part. Therefore, the all-solid-state air battery 1 of the present embodiment can charge and discharge a large current.

  The fired laminate 100 is sealed, for example, in a coin cell. The sealing method is not particularly limited. For example, you may seal the laminated body 100 after baking with resin. The coin cell is provided with a means for introducing air into the positive electrode part 200. This means for introducing air is provided using a known method. Note that a conductive layer such as a metal layer may be formed on the positive electrode part 200 and the negative electrode part 400 in order to draw current efficiently from the positive electrode part 200 and the negative electrode part 400. Examples of the method for forming the conductive layer include a sputtering method. As another method for forming the conductive layer, a metal paste may be applied or dipped and the metal paste may be heat-treated.

  The method for laminating the green sheets is not particularly limited, but the green sheets are laminated using a hot isostatic press (HIP), a cold isostatic press (CIP), a hydrostatic press (WIP), or the like. be able to.

  The slurry for forming the green sheet can be prepared by wet-mixing a solution obtained by dissolving a polymer material in a solvent, a positive electrode active material powder, a negative electrode active material powder, and a solid electrolyte powder. Specifically, a ball mill method, a viscomill method, a sand mill method, a high-pressure homogenizer method, a kneader dispersion method, or the like can be used.

  The slurry may contain a plasticizer. Although the kind of plasticizer is not particularly limited, phthalic acid esters such as dioctyl phthalate and diisononyl phthalate may be used.

In the firing step, the atmosphere is not particularly limited, but it is preferably performed under conditions that do not change the valence of the transition metal contained in the electrode active material. More desirable is an oxidizing atmosphere, particularly an air atmosphere. The firing temperature is preferably 600 to 1100 ° C.
Firing in the firing step may be performed under the condition that the interface resistance between the positive electrode part 200 and the solid electrolyte part 300 and between the negative electrode part 400 and the solid electrolyte part 300 can be reduced. For example, it is 600-1100 degreeC.

  The negative electrode part 400 may be formed by producing a negative electrode green sheet and firing it integrally with the solid electrolyte part 300 in the same manner as the positive electrode part 200. In this case, the solid electrolyte layer C is not provided with a portion that becomes the negative electrode portion 400. In manufacturing the negative electrode part 400 in this case, first, a negative electrode active material powder, a solid electrolyte powder, a conductive material powder, and a binder are prepared, and a negative electrode slurry is prepared. As the solid electrolyte powder, the solid electrolyte 3 used for the solid electrolyte layer 3 is used. Next, a negative electrode green sheet is produced from this negative electrode slurry.

  Then, the positive electrode green sheet, the solid electrolyte green sheet, and the negative electrode green sheet are stacked in this order to form the stacked body 100. The produced laminate 100 is integrally fired. As described above, the positive electrode green sheet, the solid electrolyte green sheet, and the negative electrode green sheet are combined and integrated. That is, the positive electrode material 2, the solid electrolyte 3, and the negative electrode material 4 are combined and integrated.

  Also in this case, since the positive electrode material 2 and the negative electrode material 4 use the same solid electrolyte as that of the solid electrolyte 3 as a base material, the manufactured laminate 100 has the negative electrode part 400 from the positive electrode part 200 through the solid electrolyte part 300. Until then, a matrix structure using the same solid electrolyte as a base material is constructed. Therefore, it is possible to suppress a decrease in ionic conductivity due to the interface resistance at the boundary between the respective parts. Therefore, the all-solid-state air battery 1 of the present embodiment can charge and discharge a large current.

(Second Embodiment)
Hereinafter, description will be given with reference to FIGS. 2A to 2C and FIGS. The present embodiment is an all-solid-state air battery including a positive electrode, a solid electrolyte layer, and a negative electrode using the same solid electrolyte as a base material, similar to the all-solid-state air battery of the first embodiment described above. The difference from the first embodiment is that the positive electrode 500 and the negative electrode 600 of this embodiment include a positive electrode comb 21 and a negative electrode comb 41 as shown in FIG. 3B. Accordingly, the materials described in the column of the first embodiment can be applied as the material constituting each component.

  As shown in FIG. 3B, the negative electrode 600 of the present embodiment has a negative electrode base 61 and a plurality of negative electrode combs 41 protruding from the negative electrode base 61 toward the positive electrode 500. The negative electrode base 61 is a plate-like negative electrode current collector. The negative electrode comb 41 is made of a plate-like negative electrode material, and occludes or releases lithium ions through the adjacent positive electrode comb 21 and the solid electrolyte 31. The negative electrode base 61 exchanges electrons associated with insertion and extraction of lithium ions performed by the negative electrode comb body 41.

  The positive electrode 500 of the present embodiment has a positive electrode base 51 and a plurality of positive electrode comb bodies 21 protruding from the positive electrode base 51 toward the negative electrode 600. The positive electrode base 51 is a plate-like positive electrode current collector. The positive electrode comb 21 is made of a plate-like positive electrode material, and occludes or releases lithium ions through the adjacent negative electrode comb 41 and the solid electrolyte 31. The positive electrode base 51 transmits and receives electrons associated with insertion and extraction of lithium ions performed by the positive electrode comb body 21. The combined shape of the negative electrode base 61 and the negative electrode comb body 41 and the combined shape of the positive electrode base 51 and the positive electrode comb body 21 are both comb-like shapes.

  In the all-solid-state air battery 11 of the present embodiment, the negative electrode base 61 and the positive electrode base 51 are arranged in parallel with a space therebetween. The negative electrode comb 41, the positive electrode comb 21, and the solid electrolyte 31 exist between the negative electrode base 61 and the positive electrode base 51. As for the arrangement of the negative electrode comb body 41, the positive electrode comb body 21, and the solid electrolyte 31, the negative electrode comb body 41 and the positive electrode comb body 21 are alternately provided with a gap, and the solid electrolyte 31 exists in this gap. That is, the negative electrode comb body 41 and the positive electrode comb body 21 are alternately meshed with each other through the solid electrolyte in a comb shape.

  Further, the negative electrode comb 41 is covered with the solid electrolyte 31 and is shielded from air. The negative electrode comb 41 is covered with the solid electrolyte 31 and shielded from the air, so that the stability of the negative electrode material is maintained.

  The positive electrode comb body 21 uses oxygen as a positive electrode active material. Therefore, the all-solid-state air battery 11 of this embodiment is provided with means for introducing air into the positive electrode comb body 21. The means for introducing air is not particularly limited as long as air is introduced into the positive electrode comb body 21. For example, the air introduction means desirably has a positive electrode base 51 which is a positive electrode current collector and is porous. In addition, it is desirable that an air introduction hole is provided on a surface adjacent to the positive electrode base 51 and the negative electrode base 61, and the air introduction hole communicates with the positive electrode comb 21. It is also desirable that the positive electrode comb 21 appears on the surface layer of the surface adjacent to the positive electrode base 51 and the negative electrode base 61 and directly contacts the outside air.

[Manufacturing of Second Embodiment]
The all-solid-state air battery 11 of this embodiment is manufactured as follows as an example.
First, the positive electrode green sheet 20 (FIG. 2A) and the solid electrolyte green sheet 30 (FIG. 2B) are produced in the same manner as described in the manufacturing column of the first embodiment. The positive electrode green sheet 20 is provided with a positive electrode comb precursor 21a, which is a portion made of a positive electrode material, and a portion composed of the solid electrolyte 3a. The positive electrode comb precursor 21a is a portion that becomes the positive electrode comb 21 after subsequent integral firing. The positive electrode comb precursor 21a is provided on the positive electrode 500 side, and the portion composed of the solid electrolyte 3a is provided on the negative electrode 600 side.

  As shown in FIG. 2B, the solid electrolyte green sheet 30 is desirably formed integrally with a portion that becomes the negative electrode comb body 41 after integral firing. That is, the solid electrolyte green sheet 30 is provided with a solid electrolyte part 30a composed of the solid electrolyte 3a and a negative electrode part 40a. The negative electrode part 40a is provided with a negative electrode comb body precursor 41a on the negative electrode 600 side and a part composed of the solid electrolyte 3a on the positive electrode 500 side. The negative electrode comb precursor 41a is a portion that becomes the negative electrode comb 41 after integral firing, and is composed of a solid electrolyte, a pore former, a binder, and, if necessary, a conductive material. The negative electrode portion 40a is provided at the other end opposite to one end of the solid electrolyte green sheet 30 on which the positive electrode green sheet 20 is laminated later.

  The positive electrode green sheet 20 is stacked on the solid electrolyte portion 30 a side of the solid electrolyte green sheet 30, and the positive electrode green sheet 20 and the solid electrolyte green sheet 30 form a cell green sheet 50. At this time, the positive electrode comb precursor 21a exists on the positive electrode 500 side but does not exist on the negative electrode 600 side. Further, the negative electrode comb precursor 41a exists on the negative electrode 600 side but does not exist on the positive electrode 500 side. More specifically, in the cross-sectional view of FIG. 2C, the positive electrode comb precursor 21 a extends vertically from one side of the positive electrode 500 toward the negative electrode 600 and does not reach one side of the negative electrode 600. Similarly, the negative electrode comb precursor 41a extends vertically from one side of the negative electrode 600 toward the positive electrode 500, and does not reach one side of the positive electrode 500. That is, it is a condition that each polar comb precursor (21a, 41a) is not in contact with the other polar side (600, 500), and the polar comb precursors are not in contact with each other.

  The plurality of cell green sheets 50 and the plurality of green sheets 60 composed only of the solid electrolyte 3a thus formed form a laminate green sheet 70 (FIG. 3A). The multilayer green sheet 70 is formed by alternately stacking a plurality of cell green sheets 50 and green sheets 60. The laminated green sheets 70 are bonded and integrated by being fired at a high temperature. After the laminated green sheet 70 is integrally fired, the negative electrode comb precursor 41a containing the pore former becomes holes. The negative electrode comb 41 is preferably formed by introducing liquefied metallic lithium into the pores at a predetermined pressure. It is also desirable that the negative electrode comb body 41 be formed by electrodepositing metallic lithium in the holes by charging and discharging.

  The all-solid-state air battery 11 of this embodiment manufactured by integrally firing as described above constitutes a matrix structure using the same solid electrolyte as a base material, as in the first embodiment. That is, the all-solid-state air battery 11 of the present embodiment has a configuration having a solid electrolyte network in which a plurality of positive electrode comb bodies 21, negative electrode comb bodies 41, and solid electrolytes 31 are integrated through the same solid electrolyte. .

Therefore, in this embodiment, the positive and negative electrodes take a comb-like shape and form the same solid electrolyte network, so that the ionic conductivity due to the interface resistance at the boundary of each layer, which has been a problem in the past, has been increased. The decrease can be suppressed. Therefore, the all-solid-state air battery 11 of the present embodiment can charge and discharge a large current.
Further, in this embodiment, the positive and negative electrodes have a comb-like shape, and the same solid electrolyte network is formed, thereby eliminating the need for a support that is required when adopting an integrated structure in a conventional air battery. It can be. Therefore, the all-solid-state air battery 11 of the present embodiment can have a highly integrated structure.

  The negative electrode comb body 41 of the all-solid-state air battery 11 of the present embodiment is covered with the solid electrolyte 31 and sealed with a negative electrode base 61 that is a negative electrode current collector. That is, since the negative electrode comb 41 is sealed by the solid electrolyte 31 and the negative electrode base 61, it does not come into contact with the atmosphere. Therefore, even if the all-solid-state air battery 11 of this embodiment is operated for a long period of time, the safety of the battery is maintained because the negative electrode does not come into contact with air.

(Deformation)
In each of the above-described embodiments, the form using Li ions as metal ions has been described. However, other metal ions other than Li ions may be used as metal ions. In the case of using Mg ions as metal ions, solid electrolyte 3 includes MgZr ₄ P ₆ O ₂₄ having a β-iron sulfate type structure, a compound in which a second phase is dispersed in this oxide (Mg _{1 + x} Zr ₄ P ₆ O _{24 + x} + xZr ₂ P (PO ₄ ) ₂ ), Zr ^{4+ of} this oxide is partially substituted with Nb ⁵⁺ , Mg _1-2y (Zr _1-y Nb _y ) ₄ P ₆ O ₂₄ , NASICON-type phosphate HfNb (PO _{4) 3} of the ^{Hf 4+} was partially replaced with ^{_{Mg 2+ (Mg z Hf 1-}} z) 4 (4-2z) Nb (PO 4) can be exemplified ₃ oxide such as the.

(Test example)
A test example will be described with reference to FIG. 4B. The positive electrode material is produced by sputtering Pt, which is a catalyst 81, in a range of 10 mm × 10 mm on LATP (LICAGC manufactured by OHARA; φ19 mm (diameter), t = 0.15 mm (thickness)), which is a solid electrolyte 82. It was done. The catalyst layer formed by the catalyst 81 was provided on the solid electrolyte 82 in a line-and-space pattern with a Pt thickness of 50 nm and an interval of 100 μm. In addition, a tab serving as a current collector is provided in a part of the catalyst layer. The tab is produced by sputtering Pt on the solid electrolyte 82 similarly to the catalyst 81, and the catalyst layer and the tab are electrically connected. As the negative electrode material 84, metallic lithium was used.

  Two laminate films of 40 mm × 40 mm were prepared as exterior materials. One laminate film was a positive electrode side laminate film 87a, and a hole having a diameter of 14.5 mm for introducing oxygen into Pt as the catalyst 81 was provided. The other laminate film is the negative electrode side laminate film 87b, and is not provided with a hole. The hole of the positive electrode side laminate film 87a was sealed with the sealing film 86 from the outside and the inside. Moreover, the nickel lead wire 85 used as a negative electrode terminal was attached to the negative electrode side laminate film 87b.

In a glove box in an inert dry atmosphere, a laminate was formed by laminating Pt-sputtered LATP, polyethylene oxide (PEO) 83 containing Li (CF ₃ SO ₂ ) ₂ N, and metallic lithium in this order. Here, the PEO layer is introduced to prevent the reduction of LATP by Li metal. This is not necessary when using LLZ or the like that does not undergo Li metal reduction.
Next, these laminates were sandwiched between positive and negative side laminate films (87a, 87b). When sandwiching the laminate between the positive electrode side and negative electrode side laminate films (87a, 87b), the catalyst layer appears in the hole of the positive electrode side laminate film 87a, and the metal lithium is in contact with the nickel lead wire 85 of the negative electrode side laminate film 87b. Is done. Finally, the inside of the laminate film is evacuated and sealed using a vacuum sealing machine to create the cell 80. And cell 80 was left still overnight in a 60 ° C thermostat.

  Thereafter, the sealing film 86 was removed so that the catalyst layer was completely exposed from the hole of the positive laminate film 87a. Moreover, the tab which is a part of a catalyst layer, and the nickel lead wire were piled up, and the positive electrode terminal was provided by joining with a silver paste.

  In order to prevent the fabricated cell from coming into contact with the atmosphere, the cell 80 was assembled in a chamber, and the cell 80 was evaluated in a pure oxygen atmosphere.

<Evaluation of all solid-state air battery>
The obtained test battery was charged and discharged at a constant current and a constant voltage in a voltage range of 2.0 to 4.0 V and a current density of 1 μAh / cm ² . The result is shown in FIG. 4A.

  The discharge capacity of the test battery was 2 μAh. Therefore, as can be seen from FIG. 4A, the test battery can be charged and discharged.

1: All-solid-state air battery of 1st Embodiment 2: Positive electrode material 3, 31, 3a: Solid electrolyte 4: Negative electrode material 100: Laminated body 200: Positive electrode part 300, 30a: Solid electrolyte part
400, 40a: negative electrode part A, 500: positive electrode B, 600: negative electrode C: solid electrolyte layer
20: Positive electrode green sheet 21a: Positive electrode comb precursor 30: Solid electrolyte green sheet 41a: Negative electrode comb precursor 50: Cell green sheet 60: Green sheet
70: Laminated green sheet 11: All-solid-state air battery of the second embodiment 21: Positive electrode comb
41: Negative electrode comb 51: Positive electrode base 61: Negative electrode base
80: Cell 81: Catalyst (Pt) 82: Solid electrolyte (LATP) 83: PEO
84: Negative electrode material (metal lithium (85: nickel lead wire (negative electrode terminal) 86: sealing film 87a: positive electrode side laminate film 87b: negative electrode side laminate film

Claims (6)

A negative electrode (B, 600) having a negative electrode material (4) capable of occluding and releasing metal ions;
A positive electrode (A, 500) having a positive electrode material (2) provided with a means for introducing air using oxygen as a positive electrode active material and having a catalyst for reducing oxygen;
An all-solid-state air battery (1) having a solid electrolyte layer (C) including a solid electrolyte (3) that conducts the metal ions, interposed between the negative electrode and the positive electrode,
The all-solid-state air battery, wherein the negative electrode material and the positive electrode material include the solid electrolyte and are integrated with the solid electrolyte layer.   The all-solid-state air battery according to claim 1, wherein the metal ions are ions of one or more metals selected from the group consisting of Li, Na, K, Mg, Ca, Fe, Zn, and Al. The solid electrolyte includes at least one inorganic solid electrolyte material selected from the group consisting of perovskite type, NASICON type, LISICON type, thio-LISICON type, γ-Li ₃ PO ₄ type, garnet type, and LIPON type. The all-solid-state air battery according to claim 1. The negative electrode (600) includes a negative electrode base (61) of a plate-like body and a negative electrode comb (41) made of a plurality of plate-like negative electrode materials protruding from the negative electrode base toward the positive electrode (500). Have
The positive electrode has a positive electrode base (51) of a plate-like body and a positive electrode comb (21) made of the positive electrode material of a plurality of plate-like bodies protruding from the positive electrode base toward the negative electrode,
The negative electrode base and the positive electrode base are juxtaposed at intervals,
The negative electrode comb body and the positive electrode comb body are alternately engaged with each other in a comb-tooth shape through the solid electrolyte (31) in the gap,
The all-solid-state air battery according to claim 1, wherein the negative electrode comb is covered with the solid electrolyte and is shielded from air.   The all-solid air battery according to claim 1, wherein the negative electrode, the positive electrode, and the solid electrolyte layer are integrally bonded by firing.   The all-solid air battery according to any one of claims 1 to 5, wherein the negative electrode is introduced or electrodeposited after the positive electrode and the solid electrolyte are integrally fired.

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