JP2019220468A - Electrode member, all-solid battery, powder for electrode member, manufacturing method of the electrode member, and manufacturing method of the all-solid battery - Google Patents

Abstract

To provide an electrode member which allows an all-solid battery to be fabricated in an inexpensive and simple manner without necessarily using a high-temperature thermal treatment process or a vacuum process which has been known in the past, and which can drive an all-solid battery thus fabricated, an all-solid battery, powder for the electrode member, and methods for manufacturing the electrode member and the all-solid battery.SOLUTION: An electrode member comprises: a solid electrolyte layer composed of a sintered body of an oxide-based solid electrolyte; and a positive electrode active material layer of a thin film shape disposed on the solid electrolyte layer, and formed from fine powder of an oxide-based positive electrode active material, of which the 10%-particle diameter (D) in a volume-based cumulative particle-size distribution is 0.01-0.5 μm, the 50%-particle diameter (D) is 0.01-1.0 μm, and in which the content of particles of 0.12 μm or less in particle diameter is 0.5 vol.% or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrode member, an all-solid battery, a powder for an electrode member, a method for manufacturing an electrode member, and a method for manufacturing an all-solid battery.

  The use of all-solid-state batteries as a power source for electric vehicles, small electronic devices, and the like has attracted attention. All-solid-state batteries use solid electrolyte materials instead of liquid electrolytes containing flammable organic solvents as in conventional lithium-ion batteries, etc. Various developments have been progressing in that large capacity, high output and long life can be expected.

  For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-149433) describes an example of an all-solid battery in which a specific element is dissolved in an interface between an electrode active material and a solid electrolyte material. Non-Patent Document 1 describes an example of an all-solid battery in which a gold layer is introduced at an interface between a solid electrolyte material and an electrode material.

JP 2013-149433 A

"Effect of Metal Thin Film Layer on Interface Formation of Solid Electrolyte Li6.25Al0.25La3Zr2O12 / Li Anode", Jungo Wakasugi et al., The 57th Battery Symposium, November 2016, p. 434

  In manufacturing an all-solid battery using an oxide-based solid electrolyte, it has been a problem that the interface between the solid electrolyte and the positive electrode active material has high resistance. For example, when a thin film process is used to form a positive electrode active material, a high-temperature heat treatment process or a vacuum process is required to crystallize the thin film. Even when powder is used, high-temperature sintering is required.

  However, when the heat treatment process is performed, a reaction or a diffusion phenomenon occurs at the interface between the solid electrolyte and the positive electrode active material, so that an unintended high-resistance layer may be formed.

  In the techniques described in Patent Document 1 and Non-Patent Document 1, certain measures have been taken from the viewpoint of lowering the resistance of the interface between the solid electrolyte and the positive electrode active material, but the manufacturing method is complicated and the manufacturing method is complicated. The cost required is high and there is still room for study.

  Therefore, the present invention provides an electrode capable of manufacturing an all-solid-state battery with low internal resistance that can be driven at room temperature by a cheap and simple method without necessarily using a conventionally known high-temperature heat treatment process or vacuum process. Provided are a member, an all-solid battery, a powder for an electrode member, and a method for manufacturing an electrode member and an all-solid battery.

In one aspect, an electrode member according to an embodiment of the present invention has a solid electrolyte layer made of a sintered body of an oxide-based solid electrolyte and a 10% particle size in a cumulative particle size distribution based on volume, which is disposed on the solid electrolyte layer. (D ₁₀ ) is 0.01 μm to 0.5 μm, 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm, and the content of particles having a particle size of 0.12 μm or less is 0.5% by volume. An electrode member including a thin-film positive electrode active material layer formed of the above-described fine powder of an oxide-based positive electrode active material.

  In the positive electrode active material layer according to the present embodiment, not only the positive electrode active material layer is formed only by the fine powder of the oxide-based positive electrode active material, but also the desired characteristics required as the positive electrode active material layer are exhibited. To this end, of course, materials well known to those skilled in the art may be further included in the fine powder. For example, a mode in which a carbon material powder and / or a metal powder for further promoting electron conductivity are mixed with a fine powder composed of an oxide-based positive electrode active material, a mode in which a solid electrolyte powder is further mixed as a lithium ion conductive auxiliary, Alternatively, a mode in which a carbon material powder for promoting electron conductivity, a metal powder, and a lithium ion conductive additive are further mixed, and such a mode can be included in the present embodiment. Further, the solidified powder is not limited to the mode constituted by a single fine particle of the positive electrode active material, and it is needless to say that a single layer or a plurality of layers of the solidified powder composed of different kinds of fine particles can be formed. It is.

In the electrode member in one embodiment according to the embodiment of the present invention, the solid electrolyte _{layer, Li 1.5 Al 0.5 Ge 1.5 P} 3 O 12, Li 0.33 La 0.55 TiO 3, Li 7 La 3 Zr 2 O 12 ( Li site And the positive electrode active material fine powder is LiCoO ₂ (substitution type such as Mg for the cobalt site). Olivine structure oxides such as LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Co _0.3 Mn _0.2 O ₂ , LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , LiNi _0.5 Mn _1.5 O ₄ , LiNiO ₂ , and LiFePO ₄ ; Any of generally known positive electrode active material materials such as a metal pyrophosphate composite oxide such as Li ₂ CoP ₂ O ₇ may be used.

In another aspect, the electrode member according to the embodiment of the present invention has a solid electrolyte layer formed of a sintered body of an oxide solid electrolyte and a solid electrolyte layer disposed on the solid electrolyte layer and having a volume-based cumulative particle size distribution of 10%. particle size (D ₁₀₎ is 0.01Myuemu～0.5Myuemu, is 50% particle size (D ₅₀₎ is 0.01Myuemu～1.0Myuemu, the content of particles smaller than the particle size 0.20μm 5 mass% or more And a thin-film (bulk) positive electrode active material layer formed of fine powder of LiNi _0.5 Mn _1.5 O ₄ .

  In one aspect, an all-solid-state battery according to an embodiment of the present invention is an all-solid-state battery using the electrode member.

In one aspect, the powder for an electrode member according to the embodiment of the present invention has a 10% particle size (D ₁₀ ) of 0.01 μm to 0.5 μm and a 50% particle size (D ₅₀ ) in a cumulative particle size distribution on a volume basis. A solid made of an oxide-based positive electrode active material having a particle size of 0.01 μm to 1.0 μm and a particle size of 0.12 μm or less having a volume content of 0.5% by volume or more, and a sintered body of an oxide-based solid electrolyte It is a powder for an electrode member for forming a positive electrode active material layer on an electrolyte layer.

In one aspect of the method for manufacturing an electrode member according to an embodiment of the present invention, a 10% particle size (D ₁₀ ) in a cumulative particle size distribution on a volume basis is formed on a solid electrolyte layer formed of a sintered body of an oxide-based solid electrolyte. Is an oxide type having a particle size (D ₅₀ ) of 0.01 μm to 1.0 μm, a particle size of 0.12 μm or less, and a content of 0.5% by volume or more. By depositing the fine powder composed of the positive electrode active material, applying a mechanical external force to the surface of the fine powder on the solid electrolyte layer, and bringing the fine powder into close contact with each other and solidifying, the thin film-shaped positive electrode active material layer is formed into a solid electrolyte layer. It is a manufacturing method of an electrode member including forming on it.

  In one embodiment of the method for manufacturing an electrode member according to the embodiment of the present invention, applying a mechanical external force along the surface of the fine powder causes friction at the interface between the fine powders or at the interface between the fine powder and the solid electrolyte layer. Including causing.

  In another embodiment of the method for manufacturing an electrode member according to an embodiment of the present invention, applying a mechanical external force along the surface of the fine powder includes rubbing the surface of the fine powder with a friction member.

  In one aspect, the method for manufacturing an all-solid battery according to the embodiment of the present invention includes: forming a first metal layer on a positive electrode active material layer formed on a first main surface of the solid electrolyte layer; Forming a second metal layer on a second main surface opposite to the first main surface of the solid electrolyte layer.

In another aspect, the electrode member according to the embodiment of the present invention has a solid electrolyte layer made of a sintered body of an oxide-based solid electrolyte and a 10% by volume-based cumulative particle size distribution arranged on the solid electrolyte layer. The particle size (D ₁₀ ) is 0.01 μm to 0.5 μm, the 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm, and the content of particles having a particle size of 0.12 μm or less is 0.5%. An electrode member including a bulk-shaped positive electrode mixture layer formed of a mixture of fine powder composed of an oxide-based positive electrode active material in an amount of at least% by volume and a powder composed of an oxide-based solid electrolyte.

In one embodiment of the electrode member according to the embodiment of the present invention, the powder made of an oxide-based solid electrolyte is formed by converting Li ₇ La ₃ Zr ₂ O ₁₂ (a substitution type of Al or Ga to a lithium site, and a zirconium site). , Li _1.5 Al _0.5 Ge _1.5 P ₃ O ₁₂ , Li ₃ BO ₃ (Li ₃ BO ₃ is composed of Li ₂ SO ₄ , Li ₂ CO ₃ , and Li ₄ SiO ₄ ). One or a mixture of two or more of them, including amorphous or crystallized glass), Li _1.3 Al _0.3 Ti _1.7 P ₃ O ₁₂ , and Li _0.33 La _0.55 TiO _3. You.

In another embodiment of the electrode member according to the embodiment of the present invention, the powder composed of the oxide-based solid electrolyte has a 50% particle size (D ₅₀ ) of 10 μm or less in a cumulative particle size distribution on a volume basis.

  In another embodiment of the electrode member according to the embodiment of the present invention, the mixture contains 25 to 99% by mass of a powder made of an oxide-based solid electrolyte.

  According to the present invention, a wet process or a high-temperature heat treatment process using a conventionally known binder or organic solvent, without necessarily using a vacuum process, is low enough to enable battery driving at room temperature with an inexpensive and simple method. An electrode member, an all-solid battery, a powder for an electrode member, an electrode member and an electrode member capable of producing an all-solid battery realizing internal resistance not only in an inert atmosphere but also in an air atmosphere, and a method of manufacturing an all-solid battery Can be provided.

It is sectional drawing which shows an example of the electrode member which concerns on embodiment of this invention. It is a photograph which shows an example of the fractured surface of the sintered compact (LLZ sintered compact) of the solid electrolyte layer which concerns on embodiment of this invention. 5 is a graph illustrating an example of a particle size distribution of fine powder suitable for producing an electrode member according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing a state in which fine powder for forming a positive electrode active material layer (positive electrode mixture layer) 2 on a solid electrolyte layer 1 is deposited. 5 is an electron micrograph showing an example of an electrode member according to an embodiment of the present invention. 4 is a graph showing a diffraction pattern when a supporting surface of a positive electrode active material layer of an example is measured by an X-ray diffractometer. 5 is a graph illustrating an example of charge / discharge characteristics of the all solid state battery according to the embodiment of the present invention. 5 is a Nyquist plot graph showing an example of an AC impedance measurement result of the all solid state battery according to the embodiment of the present invention. It is an electron micrograph which shows an example of the electrode member which concerns on the modification of embodiment of this invention. 6 is a graph illustrating an example of an AC impedance measurement result of the all solid state battery according to the embodiment of the present invention. 6 is a Nyquist plot graph showing an example of a measurement result of discharge rate characteristics at room temperature (25 ° C.) of the all solid state battery according to the embodiment of the present invention. 13 is a graph showing charge / discharge characteristics (CV) of Example 4.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below exemplify an apparatus or a manufacturing method for embodying the technical idea of the present invention, and the technical idea of the present invention is as follows. It is not something specific.

(First Embodiment)
As schematically shown in FIG. 1, an electrode member according to an embodiment of the present invention includes a solid electrolyte layer 1 made of a sintered body of an oxide-based solid electrolyte and a positive electrode disposed on the surface of the solid electrolyte layer 1. And an active material layer 2.

As the solid electrolyte layer 1, a solid electrolyte layer 1 made of an oxidized solid electrolyte material can be used. Examples of the oxidized solid electrolyte material include, for example, Li _1.5 Al _0.5 Ge _1.5 P ₃ O _{12 having} a NASICON type crystal structure, Li _0.33 La _0.55 TiO _{3 having} a perovskite type crystal structure, and Li ₇ La ₃ Zr ₂ O having a garnet type crystal structure. ₁₂ etc. are used. Specifically, Li _1.5 Al _0.5 Ge _1.5 P ₃ O ₁₂ , Li _0.33 La _0.55 TiO ₃ , Li ₇ La ₃ Zr ₂ O ₁₂ (substitution type such as Al or Ga for lithium site, and Nb for zirconium site Or including a substitution type such as Ta).

Among them, cubic lithium lanthanum zirconium oxide (commonly known as “LLZ”) represented by Li ₇ La ₃ Zr ₂ O ₁₂ having a garnet-type crystal structure (substitution type of Al or Ga to lithium site, and zirconium site) In addition to the high conductivity of lithium ions, and extremely low reactivity with metallic lithium as compared with other oxide-based solid electrolytes to avoid dendrite formation by lithium ions. It is particularly preferably used as an oxidized solid electrolyte material of the solid electrolyte layer 1 in that a lithium metal layer can be formed directly on the surface of a sintered substrate made of an oxide solid electrolyte.

  FIG. 2 shows a photograph of a fractured surface of the solid electrolyte layer 1. As shown in FIG. 2, the solid electrolyte layer 1 is a sintered body composed of crystal grains having a particle size of approximately 2 to 10 μm based on observation with an electron microscope, and grows into larger crystal grains by linking the crystal grains. However, the grain boundary interface is unclear. As shown in FIG. 2, the sintered body of the solid electrolyte layer 1 according to the present embodiment is a dense sintered body and has few pores. Although not limited to the following, the porosity of the solid electrolyte layer 1 is, for example, about 0.1 to 5.0%. The porosity of the solid electrolyte layer 1 can be measured based on, for example, JIS R1634 (1998).

  As a result of AC impedance measurement of the solid electrolyte layer 1 according to the present embodiment, for example, a LLZ sintered body, the solid electrolyte layer 1 has an ion conductivity of about 5.0E-4 to 2.0E-03 (S / cm). Is shown. By employing such a solid electrolyte layer 1 as a material for an electrode member, the grain boundary resistance of the solid electrolyte layer 1 can be reduced, and the ionic conductivity can be improved. By combining such an oxide-based solid electrolyte substrate with a cathode active material described below, an all-solid-state battery that can be driven by a less expensive room temperature process without using a conventional high-temperature process or the like can be obtained.

Specific examples of the fine powder used for the positive electrode active material layer 2 include lithium cobalt oxide (LiCoO ₂ ), lithium nickel cobalt manganate (LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Co _0.3 Mn _0.2 O ₂ , LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ), lithium nickel manganate (LiNi _0.5 Mn _1.5 O ₄ ), lithium nickelate (LiNiO ₂ ), lithium iron phosphate (LiFePO ₄ ), lithium cobalt phosphate (Li ₂ CoP ₂ O) ₇ ) etc. are available. Among them, it is preferable to use lithium cobaltate, lithium nickel cobalt manganate, and lithium nickel manganate as the material of the positive electrode active material layer 2.

  The positive electrode active material layer 2 is made of fine powder of an oxide-based positive electrode active material or powder of a mixture of an oxide-based positive electrode active material and an oxide-based solid electrolyte powder (hereinafter, also referred to as “positive electrode mixture”). The powders contained are solidified in close contact with each other, and are formed of a solidified powder having a thin film shape or a bulk shape. The solidified powder is solidified and adhered by mechanical external force applied to the surface of the powder including the fine powder of the oxide-based positive electrode active material or the positive electrode mixture, as if it were a sintered body. It means a layer that has been solidified by bonding of grain boundaries between the layers and has become bulky. In the production, high-temperature conditions (at least 500 ° C. or more) are not necessarily required at the interface with the solid electrolyte layer 1, and for example, about room temperature (specifically, about 1 to 30 ° C., more specifically, 15 to 30 ° C.). (25 ° C.). A method for forming the positive electrode active material layer (positive electrode mixture layer) 2 made of the solidified powder will be described later.

In order to appropriately form the positive electrode active material layer (positive electrode mixture layer) 2 composed of the solidified powder on the solid electrolyte layer 1, it is particularly important to appropriately select the properties of the fine powder as a raw material. In the electrode member according to the present embodiment, the plasticity (fine crystal grain superplasticity) of the fine powder and the mechanical adhesive force (including the anchor effect) at the interface between the fine powder and the solid electrolyte layer, the chemical adhesive force, or the diffusion adhesive force Needs to be obtained more appropriately. In order to form the solidified powder according to the present embodiment, it is desirable that the ratio of the ultrafine powder having a diameter of less than 100 nm, which is referred to as nanoparticles, be as high as possible. In particular, the 10% particle size (D ₁₀ ) in the cumulative particle size distribution on a volume basis. It is more preferable to use an oxide-based positive electrode active material having a particle size of 0.01 μm to 0.5 μm and a 50% particle diameter (D ₅₀ ) of 0.01 μm to 1.0 μm as a raw material.

If the 10% particle size (D ₁₀ ) of the fine powder is larger than 0.5 μm, the fine powders may not adhere well to the solid electrolyte layer 1 and a solidified powder may not be formed. In order to form a more suitable powder solidified body as the positive electrode active material layer (positive electrode mixture layer) 2 of the all solid state battery, the smaller the average particle size (D ₅₀ ) of the fine powder is, the more preferable it is, 0.15 μm or less. Is more preferably 0.12 μm or less, and still more preferably 0.1 μm or less. The 10% particle size (D ₁₀ ) of the fine powder is not limited to the following, but is preferably, for example, 0.01 μm or more, and more preferably 0.02 μm or more, from the viewpoint of handleability and the like.

When, for example, lithium cobaltate is used as the fine powder, the 10% particle size (D ₁₀ ) is 0.01 to 0.3 μm, further 0.01 to 0.2 μm, and further 0.01 to 0.17 μm. It is preferable to use fine powder of When, for example, lithium nickel manganate is used as the fine powder, the 10% particle size (D ₁₀ ) is 0.01 to 0.4 μm, preferably 0.01 to 0.35 μm, and more preferably 0.01 to 0.3 μm. It is preferable to use a fine powder of 3 μm. When nickel nickel lithium manganate is used as the fine powder, a fine powder having a 10% particle size (D ₁₀ ) of 0.01 to 0.5 μm, more preferably 0.01 to 0.3 μm can be used. .

If the 50% particle size (D ₅₀ ) of the fine powder is larger than 1.0 μm, the fine powder does not adhere well to each other, and the positive electrode active material layer (positive mixture layer) 2 composed of the solidified powder has a required thickness. May not be formed. The 50% particle size (D ₅₀ ) of the fine powder is preferably as small as possible, preferably 0.8 μm or less, more preferably 0.5 μm or less, and still more preferably 0.3 μm or less. On the other hand, the lower limit of the 50% particle size (D ₅₀ ) of the fine powder is not limited to the following, but it can be, for example, 0.01 μm or more, and more preferably 0.05 μm or more. It is more preferably 0.1 μm or more from the viewpoint of properties.

FIG. 3 shows an example of the cumulative particle size distribution of fine powder suitable as the fine powder used for the positive electrode active material layer (positive electrode mixture layer) 2. As shown in FIG. 3, the 50% particle size (D ₅₀ ) of the cumulative particle size distribution is in the range of 0.01 to 1.0 μm in the range of 0.01 to 1.4 μm, and further in the range of 0.1 to 1.0 μm. It is particularly preferable to use a fine powder from the viewpoint of workability.

Further, a fine powder having a ratio (D ₅₀ / D ₁₀ ) of 50% particle size (D ₅₀ ) to 10% particle size (D ₁₀ ) in the cumulative particle size distribution on a volume basis is 3 or less, more preferably 2 or less. It is preferable to use a fine powder having a ratio (D ₉₀ / D ₁₀ ) of 90% particle size (D ₉₀ ) to 10% particle size (D ₁₀ ) of 10 or less, more preferably 6 or less.

  The fine powder having such characteristics contains a fine powder having a particle diameter of about 0.12 μm or 0.08 μm or less at a predetermined ratio, which is considered to greatly contribute to the formation of the solidified powder according to the present embodiment. This is particularly preferable because the solidified powder according to the embodiment can be easily deposited to an appropriate thickness.

  For example, when lithium cobaltate, lithium nickel cobalt manganate, or lithium nickel manganate suitable as fine powder is used, particles having a particle size of 0.12 μm or less in the raw material are, for example, 0.5 volume% or more, preferably It contains 2% by volume or more, more preferably 5% by volume or more, and contains particles having a particle size of 0.08 μm or less in the raw material, for example, 0.1% by volume or more, preferably 0.5% by volume or more, more preferably 2% by volume. The use of the fine powder containing the above is preferable in that the solidified powder can be appropriately and easily formed. The upper limit of the composition ratio of the particles having a particle size of 0.12 μm or less in the raw material is not particularly limited, and the upper limit is more preferable.

On the other hand, even if the 10% particle size (D ₁₀ ) and the 50% particle size (D ₅₀ ) are adjusted to an appropriate range, particles having a particle size of 0.12 μm or less are, for example, less than 0.5% by volume. In some cases, the cathode active material layer 2 can be formed in a small amount, but cannot be deposited to such a thickness that it can function as a cathode active material layer of an all-solid-state battery. Although not limited to the following, the content of particles having a particle size of 0.12 μm or less in the raw material can be preferably 0.5 to 15% by volume, and more preferably 2 to 4% by volume. Is preferred.

  When lithium nickel cobalt manganate is used as a fine powder, a material containing 5% by volume or more, preferably 10% by volume or more, more preferably 15% by volume or more of particles having a particle size of 0.20 μm or less is used. Good. The particle size range suitable for the formation of the solidified powder varies depending on the type of the material used for the fine powder, but the oxide-based positive electrode active material shown above as the material of the positive electrode active material layer (positive electrode mixture layer) 2 It can be said that any fine powder containing at least 0.5% by volume of particles having a particle size of 0.12 μm or less can be suitably used. The content of the particles having a predetermined particle size or less is not limited to the above, and the higher the content, the more efficiently the positive electrode active material layer (positive electrode mixture layer) 2 can be formed.

In the present embodiment, the “particle size” refers to a particle size based on a volume-based cumulative particle size curve of a particle size distribution measured using a laser diffraction / scattering type particle size distribution measuring device. “D ₁₀ ”, “D ₅₀ ”, and “D ₉₀ ” mean 10% particle size, 50% particle size, and 90% particle size, respectively, on a volume basis in the cumulative particle size distribution, and are represented by a laser diffraction / scattering particle size. In the cumulative particle size curve of the particle size distribution measured using a distribution measuring device, the particle size when the integrated amount occupies 10%, 50%, and 90% on a volume basis, respectively.

  The particle size of the fine powder can be measured using, for example, a laser diffraction / scattering type particle size distribution measuring device “Microtrac MT-3000” manufactured by Microtrac Bell Co., Ltd., and the attached software is used from the measurement result. Thus, the cumulative particle size distribution on a volume basis can be evaluated.

  By using a fine powder having such a distribution, mechanical adhesion and diffusion bonding between the fine powders are caused by applying a slight mechanical external force to the surface, and thereby, the fine particles of the positive electrode active material, or a positive electrode described later. The active material fine powder and the oxide solid electrolyte powder can be closely adhered and fixed. The electrode member thus obtained has good adhesion between the solid electrolyte layer 1 and the positive electrode active material layer (positive electrode mixture layer) 2 and can form a low-resistance interface. The battery can be sufficiently driven at room temperature. The particle size distribution can be measured by a measurement method known to those skilled in the art. The solid electrolyte layer 1 and the positive electrode active material are further heated by subjecting the electrode member thus obtained to a heat treatment at 100 to 500 ° C. for 10 seconds to 1 hour in an air atmosphere, an inert atmosphere, or an oxygen atmosphere. In some cases, the interface with the layer (positive electrode mixture layer) 2 can be reduced in resistance.

  As shown in the schematic diagram of FIG. 4, the electrode member according to the embodiment of the present invention is obtained by depositing the above fine powder on the surface of the sintered body of the solid electrolyte layer 1 having minute irregularities, By applying a mechanical external force from above to the inside of the solid electrolyte layer 1, a thin-film positive electrode active material layer 2 is formed as shown in FIG. This is because of the plasticity of nanoparticles (particle diameter of 0.1 μm or less) and fine particles having a particle diameter of about 0.1 μm having a particle diameter close to the nanoparticles, sintered only by applying pressure to the surface of the fine powder. This utilizes the phenomenon in which fine powders are integrated into a bulk.

  Although the present embodiment is not intended to be limited by the following inference, the solid electrolyte layer 1 having a higher release of the enormous surface energy of the fine powder and the solid electrolyte layer 1 having a higher hardness than the fine powder may be used. By pressing the fine powder having a hardness lower than 1, the compaction proceeds due to the binding of the positive electrode active material powder to form a solidified powder, and is uniform and strong due to the adhesive force such as an anchor effect between the solid electrolyte layer and the solid electrolyte layer. It is presumed that a thin interface (solidified powder) having a certain gloss is formed on the external surface by forming an appropriate interface.

  Conventionally, various techniques for forming a thin film by applying a mechanical or other external force to a powder or a sintered body thereof have been known. For example, there is a method in which a conventional vacuum process such as a sputtering method or a PLD (pulse laser deposition method) or a powder called an aerosol deposition method is sprayed at a high speed and a kinetic energy forms a thin film made of a powder material on a substrate. is there. In recent years, there have been cases in which a thin film is formed on a substrate by such a vacuum process or aerosol deposition method to achieve battery driving. Considering the equipment introduction and running costs, it can be said that the production process of the secondary battery product is extremely expensive.

On the other hand, according to the electrode member according to the embodiment of the present invention and the all-solid-state battery using the same, a sintered body of an oxide-based solid electrolyte is used as the solid electrolyte layer 1, Particles having a 10% particle size (D ₁₀ ) in the particle size distribution of 0.01 μm to 0.5 μm and a 50% particle size (D ₅₀ ) of 0.01 μm to 1.0 μm and a particle size of 0.12 μm or less are defined as 0.1%. The positive electrode active material layer 2 is provided with a thin-film solidified powder in which fine powders of an oxide-based positive electrode active material containing 5% by volume or more, and more preferably 5% by volume or more, adhere to each other and solidify. With such a configuration, the joining between the solid electrolyte layer 1 and the positive electrode active material layer 2 can be performed inexpensively and easily at room temperature without depending on a vacuum process or the like. Further, by producing an all-solid-state battery with the obtained electrode member by, for example, a method described below, the obtained all-solid-state battery can be driven as a battery at room temperature.

For example, on the positive electrode active material layer 2 formed on the first main surface which is one surface of the solid electrolyte layer 1 of the above-mentioned electrode member, a metal layer such as gold (Au) is used as a first collector electrode layer. Is formed. Further, a second negative electrode layer made of, for example, metallic lithium (Li) is formed on a second main surface opposite to the first main surface, which is the other surface of the solid electrolyte layer 1, to obtain an all-solid-state battery. . According to the present embodiment, the internal resistance of the obtained all-solid-state battery is as small as about 1000 to 5000 Ω · cm ² (when the thickness of the solid electrolyte layer is about 0.5 mm to 1 mm), which is a simpler and cheaper method. Accordingly, it is possible to provide an electrode member, an all-solid-state battery, and a method for manufacturing the same that can be driven at room temperature (25 ° C.).

An electrode member and an all-solid-state battery manufacturing method according to an embodiment of the present invention will be described. First, the solid electrolyte layer 1 is prepared, and the 10% particle size (D ₁₀ ) in the cumulative particle size distribution on a volume basis is 0.01 μm to 0.5 μm, and the 50% particle size (D ₅₀ ) Deposits a fine powder made of an oxide-based positive electrode active material containing 0.5% by volume or more of particles having a particle size of 0.01 μm to 1.0 μm and a particle size of 0.12 μm or less. The fine powder is deposited on the entire surface of the solid electrolyte layer 1. For example, it is preferable to deposit a total amount of about 0.05 to 10 mg, and preferably about 0.1 to 10 mg, on the surface (surface area 100 mm ² ) of the solid electrolyte layer 1.

  Next, by applying a mechanical external force along the surface of the fine powder on the solid electrolyte layer 1, a solidified powder having a certain film thickness in which the fine powder is in close contact with each other is formed on the surface of the solid electrolyte layer.

  As a method of applying a mechanical external force along the surface of the fine powder on the solid electrolyte layer 1, for example, a predetermined pressure is applied to the entire surface of the fine powder. For example, by applying a pressure of 10 kPa to 500 kPa, preferably 20 kPa to 300 kPa, and further about 50 kPa to 200 kPa from the surface of the fine powder, the fine powders are brought into close contact with each other and solidified to form a powder solidified body, A low-resistance interface between the solid electrolyte layer 1 and the solidified powder can be formed.

  Specifically, it is preferable to apply a mechanical external force so as to cause friction on the fine powder on the solid electrolyte layer 1. For example, there is a method in which the surface of the fine powder is rubbed in a predetermined direction with a friction member such as cloth or paper. Various materials such as paper waste, cloth waste, and resin fiber can be used as the friction member. When the surface of the fine powder is rubbed with a friction member made of cloth, paper, resin or the like, the rubbing direction is not particularly limited, and it may be rubbed in one specific direction or in multiple directions.

  According to the method for manufacturing the electrode member and the all-solid-state battery according to the embodiment of the present invention, since the production of the positive electrode active material layer does not necessarily require a high-temperature heat treatment, the solid electrolyte layer 1 and the positive electrode active material layer 2 Reaction and diffusion phenomena between substances at the interface can be suppressed, and formation of an unintended high-resistance layer can be suppressed. As a result, a lower resistance electrode member can be manufactured.

  In addition, by applying pressure to a specific fine powder and solidifying the fine powder, it can be driven as a solid battery at a simpler and lower cost than a process using a known aerosol deposition (AD) device. A possible level of electrode members can be manufactured.

(Second embodiment)
An electrode member according to another embodiment of the present invention has a 10% particle size (D ₁₀ ) of 0.01 μm to _0.5 μm and a 50% particle size (D ₅₀ ) of 0.01 μm in a cumulative particle size distribution on a volume basis. A mixture of a fine powder of an oxide-based positive electrode active material containing 0.5% by volume or more of particles having a particle size of 0.12 μm or less and a powder of an oxide-based solid electrolyte (a positive electrode mixture ) Is prepared, and the positive electrode mixture is placed on the solid electrolyte layer 1 and a predetermined pressure similar to the above is applied to the entire surface of the positive electrode mixture, whereby the positive electrode mixture composed of a powder solidified body in which powders are in close contact with each other is prepared. And forming the material layer 2.

Examples of the powder composed of the oxide-based solid electrolyte include, in addition to the above-described LLZ, Li _1.5 Al _0.5 Ge _1.5 P ₃ O ₁₂ (LAGP), Li ₃ BO ₃ (LBO) (Li ₃ BO ₃ to Li ₂ SO ₄ , One or a mixture of two or more of the material groups Li ₂ CO ₃ and Li ₄ SiO ₄ , including amorphous or crystallized glass), Li _1.3 Al _0.3 Ti _1.7 P ₃ O ₁₂ (LATP), Li _0.33 A material selected from any one or more of the group consisting of La _0.55 TiO ₃ (LLTO) can be used, and preferably, one or two of these solid electrolyte materials are used.

Regarding the particle size of the oxide solid electrolyte to be added, the 50% particle size (D ₅₀ ) in the cumulative particle size distribution on a volume basis is preferably 10 μm or less, more preferably 5 μm or less.

  The optimal composition ratio between the fine powder of the oxide-based positive electrode active material in the mixture and the powder of the oxide-based solid electrolyte can be adjusted by a combination of materials. It is preferable that the volume of the powder composed of the solid electrolyte is 25 to 99%.

For example, as fine powder composed of an oxide-based positive electrode active material, LCO (lithium cobalt oxide (LCO)) fine powder (manufactured by Toyo Seisakusho Co., Ltd., 10% particle size (D ₁₀ ) 0.097 μm, 50% particle size (D ₅₀ ) Using 0.208 μm, 90% particle size (D ₉₀ ) 0.534 μm), and mixing LAGP having an average particle size (D ₅₀ ) of 1.5 μm as a powder composed of an oxide solid electrolyte to form a mixture. The interface resistance between the solid electrolyte and the positive electrode mixture layer in the case where the mixture was prepared and this mixture was arranged on the solid electrolyte layer 1 to form the positive electrode mixture layer 2 has a tendency as shown in Table 1.

  As shown in Table 1, when LCO and LAGP are mixed, LAGP, which is a powder composed of an oxide-based solid electrolyte, is mixed in the mixture at a mass ratio of 30 to 50%, and more preferably 35 to 40%. In addition, the interface resistance with the solid electrolyte can be further reduced.

  Prior to forming the positive electrode mixture layer 2 by supporting the mixture on the solid electrolyte layer 1, heat treatment of the mixture may further reduce the interface resistance with the solid electrolyte layer 1. For example, a solid electrolyte layer 1 and a positive electrode mixture layer are obtained by subjecting a raw material obtained by mixing LCO: LAGP at a ratio of 75:25 mass% to heat treatment typically at 300 to 400 ° C. for 1 to 10 hours in an oxygen atmosphere. In some cases, the interfacial resistance with No. 2 can be significantly reduced. Optimum heat treatment conditions vary depending on the combination of materials, but at least the heat treatment temperature must be lower than the temperature at which the mixed materials react. For example, in the case of LCC + LLZ, about 500 ° C., and in the case of LCO + LAGP, about 400 ° C., which is a limit temperature at which a chemical reaction (decomposition) does not occur between materials. .

  An electrode member including the positive electrode mixture layer 2 using a mixture of the positive electrode active material fine powder and the solid electrolyte powder and a method for manufacturing an all-solid battery used the fine powder composed of the above-described oxide-based positive electrode active material alone. It is the same as the manufacturing method in the case.

  As described above, the present invention has been described with reference to the above embodiments. However, it should not be understood that the description and drawings constituting a part of the present disclosure limit the present invention. That is, the present invention is not limited to each embodiment, and can be embodied by modifying the components without departing from the scope of the invention. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in each embodiment. For example, some components may be deleted from all the components shown in the embodiment. Further, components of different embodiments may be appropriately combined.

  Hereinafter, Examples of the present invention are shown together with Comparative Examples, but these Examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

-Example 1-
(Preparation of electrode member)
A Li ₇ La ₃ Zr ₂ O ₁₂ sintered body substrate (hereinafter referred to as “LLZ substrate”) (size 10 mm × 10 mm × 0.5 mmt) is sandpapered (manufactured by Sankyo Rikagaku Co., Ltd.) in a glove box in an argon gas atmosphere. After polishing on both surfaces of the sintered body substrate, lithium cobalt oxide (LCO) fine powder (manufactured by Toshima Seisakusho Co., Ltd., 10% particle size (D ₁₀ ) 0.097 μm, 50% particle size (D ₅₀ ) 0. Particles having a unimodal distribution of 208 μm, 90% particle diameter (D ₉₀ ) 0.534 μm, and particles having a particle diameter of 0.12 μm or less and having a density of 11.87 vol. The positive electrode active material layer was supported by applying a mechanical external force of 10 kPa to 500 kPa so as to rub against the LLZ substrate using (Nippon Paper Crecia Co., Ltd.). When the weight of the positive electrode active material layer formed by the micro balance was measured, it was confirmed to be 0.25 mg from the difference from the previously measured LLZ substrate weight.

When the positive electrode active material supporting surface of the sample was measured with an X-ray diffractometer, a diffraction pattern derived from LiCoO ₂ was confirmed together with the diffraction pattern of the LLZ substrate (FIG. 6). Further, when the cross section of the sample was observed with a scanning electron microscope, it was observed that a film having a certain thickness was formed on the substrate (FIG. 5). From these analysis results, it was confirmed that the positive electrode active material layer composed of the solidified powder of the lithium cobalt oxide fine powder was definitely supported on the LLZ substrate.

(Preparation of all solid state battery)
The following operation was performed to produce an all-solid lithium ion secondary battery. Au was formed as a collecting electrode on the surface of the electrode member supporting the positive electrode active material on the side of the positive electrode active material layer by a sputtering apparatus (manufactured by Sanyu Electronics) (film thickness: 0.5 μm). On the other hand, a metal Li film was formed as a negative electrode on the opposite side of the electrode member on which Au was formed by a resistance heating evaporator (film thickness: 5 μm).

  The lithium ion secondary battery was set in a beaker cell, and the Au collector electrode surface was connected to the anode terminal, the Li negative electrode surface was connected to the cathode terminal, and various electrochemical measurements were performed using a potentiogalvanostat device. As a result of performing a charge / discharge test while changing the discharge rate in the order of CC-CV charge (1C → CV 4.2V, 2h charge) and 1C, 0.5C, 0.2C, 0.1C, and 1C again, a good battery was obtained. Driving was confirmed (FIG. 7). After completion of the charging, the impedance was measured (AC impedance measuring device attached to the potentiogalvanostat device), and the internal resistance of the all-solid-state battery was about 2 kΩ (FIG. 8).

(Effects on electrode member production due to differences in fine powder)
By changing the material of the solid electrolyte layer and the particle diameter of the fine powder constituting the positive electrode active material layer carried thereon as shown in Tables 2 to 4, the above-described method for producing the electrode member and the production of the all-solid-state battery It was evaluated whether the electrode member according to the present embodiment can be manufactured according to the method. "Content" in Tables 2 to 4 is obtained from the measurement result of the cumulative particle size distribution on a volume basis using a laser diffraction / scattering type particle size distribution analyzer "Microtrac MT-3000" manufactured by Microtrac Bell Co., Ltd. Was.

As shown in Table 2, the 10% particle size (D ₁₀ ) is 0.01 μm to 0.5 μm, the 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm, and the particle size is 0.12 μm or less. When a fine powder of an oxide-based positive electrode active material containing 0.5% by volume or more of particles was used, a positive electrode active material layer could be appropriately formed on the solid electrolyte layer. When the 10% particle size (D ₁₀ ) and the 50% particle size (D ₅₀ ) are out of the appropriate range and do not include particles having a particle size of 0.12 μm or less (the rightmost column), a positive electrode active material layer is formed. Could not.

As shown in Table 3, when nickel manganate fine powder is used, the 10% particle size (D ₁₀ ) is 0.01 μm to 0.5 μm, and the 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm. When a fine powder containing 0 μm and 5% by volume or more of particles having a particle size of 0.20 μm or less was used (left column), a positive electrode active material layer could be appropriately formed. A material in which the properties of the fine powder were out of the appropriate range (right column) could not form a positive electrode active material layer.

As shown in Table 4, the 10% particle size (D ₁₀ ) is 0.01 μm to 0.5 μm, the 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm, and the particle size is 0.12 μm or less. When a fine powder of an oxide-based positive electrode active material containing 0.5% by volume or more of particles was used (left column), a positive electrode active material layer could be appropriately formed on the solid electrolyte layer. When the properties of the fine powder were not within an appropriate range (right column), the positive electrode active material layer could not be formed.

  On the other hand, a fine powder of an oxide solid electrolyte is deposited on the positive electrode active material layer made of a sintered body of the above-described oxide-based positive electrode active material by the above-described procedure, and a frictional force is applied to the oxide solid electrolyte to form a powder. When an attempt was made to form a solidified layer, a solid electrolyte layer could not be formed on the positive electrode active material layer.

Example 2
(Preparation of positive electrode mixture)
The same LCO fine powder as in Example 1 and the LAGP solid electrolyte powder produced by the solid-phase synthesis method were mixed at room temperature (25 ° C.) in the air so that LCO: LAGP became 75:25 in mass ratio, Stirring and mixing were performed for 10 minutes using an agate mortar to obtain a mixed powder. The obtained mixed powder was subjected to a heat treatment at 350 ° C. for 3 hours in an air atmosphere to obtain a positive electrode mixture composed of a mixture of LCO and LAGP.

(Preparation of electrode member)
As a solid electrolyte layer, a Ga-doped LLZ (hereinafter referred to as “LLZ substrate”) having a relative density of 95% or more and a thickness of 10 mm square and a thickness of 1 mm (hereinafter referred to as “LLZ substrate”) was prepared as a solid electrolyte layer. Polishing was performed at (# 400). An appropriate amount of the above-described positive electrode mixture was contained in the nonwoven fabric, and about 0.3 mg of the positive electrode mixture was carried on the polished surface of the LLZ substrate by applying an external pressure of about 10 kPa to 500 kPa. The LLZ substrate supporting the positive electrode mixture was heated at 350 ° C. for 30 minutes in an air atmosphere to prepare an electrode member. When a cross section of this electrode member was observed with a scanning electron microscope, it was observed that a film having a constant thickness was formed on the substrate (FIG. 9). From these analysis results, it was confirmed that the positive electrode mixture layer formed of the LCO and LAGP mixed fine powder was definitely supported on the LLZ substrate.

(Preparation of all solid state battery)
After the heat treatment, a 0.5 μm-thick Au film is formed by sputtering on the positive electrode active material layer of the LLZ substrate that has been cooled to room temperature, and the surface of the LLZ substrate opposite to the Au-deposited surface is polished with sandpaper (# 1000). did. An all-solid-state battery was produced by pressing a metal indium sheet on the polished surface to form a negative electrode.

Example 3
An all-solid-state battery was manufactured in the same manner as in Example 2, except that the composition ratio of the positive electrode mixture was LCO: LAGP = 50: 50.

Example 4
An all-solid-state battery was manufactured in the same manner as in Example 2, except that the composition ratio of the positive electrode mixture was LCO: LAGP = 65: 35.

Example 5
An all-solid-state battery was fabricated in the same manner as in Example 2, except that the composition ratio of the positive electrode mixture was LCO: LAGP = 55: 45.

(Evaluation of battery characteristics)
For the all solid state batteries manufactured in Examples 2 to 5, AC impedance measurement was performed with an electrochemical measurement device (VSP-300 manufactured by BioLogic), and the internal resistance of the all solid state batteries at room temperature (25 ° C.) was measured. did. The results are shown in FIG. As shown in FIG. 10, all of Examples 2 to 5 can realize a low internal resistance enough to enable battery driving at room temperature, and particularly, Example 4 can realize the lowest battery internal resistance. Was.

The charge / discharge characteristics (constant current-constant voltage charge / discharge test) at room temperature (25 ° C.) of the all-solid-state battery prepared in Example 4 at room temperature (25 ° C.) were measured using an electrochemical measurement device (VSP-300 manufactured by BioLogic). Click voltammetry). FIG. 11 shows the measurement results of the discharge rate characteristics of the all solid state battery at room temperature (25 ° C.), and FIG. 12 shows the charge / discharge characteristics (CV). In the discharge rate measurement, changes in the battery capacity at different discharge rates were examined at a constant charge current (CCCV discharge combining a constant current (50 μA / cm ² ) -constant voltage (3.58 V for 2 hours)). The discharge was performed in the order of 1 to 7 shown in FIG.

Although the discharge capacity decreased as the current density during discharge increased, a discharge current of 0.5 mA / cm ^{2 at} maximum was obtained (see “4” in FIG. 11). In “1”, “4”, and “7” where the discharge was performed at the same 25 μA / cm ² , a discharge capacity almost equivalent to “1” was obtained in “4”. However, at "7", the discharge capacity was slightly reduced. This is because a relatively large current of 0.25 mA / cm ² (“5”) to 0.5 mA / cm ² (“6”) has passed, and the solid electrolyte layer or the positive electrode mixture layer or the solid electrolyte layer It can be considered that this is caused by the occurrence of some resistance component at any or a plurality of points on the interface of the positive electrode mixture layer.

1 solid electrolyte layer 2 positive electrode active material layer

Claims (13)

A solid electrolyte layer made of a sintered body of an oxide solid electrolyte,
The 10% particle size (D ₁₀ ) in the cumulative particle size distribution on a volume basis is 0.01 μm to 0.5 μm, and the 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm. And a thin-film positive electrode active material layer formed of a fine powder of an oxide-based positive electrode active material having a particle size of 0.12 μm or less and a content of 0.5% by volume or more. Electrode member. The solid electrolyte layer is composed of Li _1.5 Al _0.5 Ge _1.5 P ₃ O ₁₂ , Li _0.33 La _0.55 TiO ₃ , Li ₇ La ₃ Zr ₂ O ₁₂ (Al or Ga substitution type for lithium site, and Nb for zirconium site) Or including a substitution form of Ta)
The method according to claim 1, wherein the fine powder contains LiCoO ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Mn _1.5 O ₄ , LiNiO ₂ , LiFePO ₄ , or Li ₂ CoP ₂ O _7. The electrode member as described in the above. A solid electrolyte layer made of a sintered body of an oxide solid electrolyte,
The 10% particle size (D ₁₀ ) in the cumulative particle size distribution on a volume basis is 0.01 μm to 0.5 μm, and the 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm. And a thin-film positive electrode active material layer formed of a fine powder of LiNi _0.5 Mn _1.5 O ₄ having a content of particles having a particle size of 0.20 μm or less of 5% by volume or more. .   An all-solid-state battery using the electrode member according to claim 1. The 10% particle size (D ₁₀ ) in the cumulative particle size distribution on a volume basis is 0.01 μm to 0.5 μm, the 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm, and the particle size is 0.12 μm or less. An electrode member powder comprising an oxide-based positive electrode active material having a particle content of 0.5% by volume or more and forming a positive electrode active material layer on a solid electrolyte layer formed of a sintered body of an oxide-based solid electrolyte . On a solid electrolyte layer made of a sintered body of an oxide-based solid electrolyte, a 10% particle size (D ₁₀ ) in a volume-based cumulative particle size distribution is 0.01 μm to 0.5 μm, and a 50% particle size (D ₅₀ ) is 50%. A fine powder of an oxide-based positive electrode active material having a particle size of 0.01 μm to 1.0 μm and a particle size of 0.12 μm or less and 0.5% by volume or more is deposited, and the fine powder on the solid electrolyte layer is deposited. A method for manufacturing an electrode member, comprising: forming a thin-film positive electrode active material layer on the solid electrolyte layer by applying a mechanical external force to the surface of the fine powder and causing the fine powder to adhere to each other and solidify.   The manufacturing of the electrode member according to claim 6, wherein applying a mechanical external force along the surface of the fine powder includes causing friction between the fine powders or an interface between the fine powder and the solid electrolyte layer. Method.   The method for manufacturing an electrode member according to claim 6, wherein applying a mechanical external force along the surface of the fine powder includes rubbing the surface of the fine powder with a friction member. A first metal layer is formed on the positive electrode active material layer formed on the first main surface of the solid electrolyte layer according to any one of claims 6 to 8,
Forming a second metal layer on a second main surface opposite to the first main surface of the solid electrolyte layer. A solid electrolyte layer made of a sintered body of an oxide solid electrolyte,
The 10% particle size (D ₁₀ ) in the cumulative particle size distribution on a volume basis is 0.01 μm to 0.5 μm, and the 50% particle size (D ₅₀ ) is 0.01 μm to 1.0 μm. And a bulk formed from a mixture of a fine powder composed of an oxide-based positive electrode active material and a powder composed of an oxide-based solid electrolyte in which the content of particles having a particle size of 0.12 μm or less is 0.5% by volume or more. An electrode member comprising: a positive electrode mixture layer of the above. Powders comprising the oxide-based solid electrolyte include Li ₇ La ₃ Zr ₂ O ₁₂ (including a substitution type of Al or Ga for a lithium site and a substitution type of Nb or Ta for a zirconium site), and Li _1.5 Al _{0.5 Ge 1.5 P 3 O 12, Li} 3 BO 3 (Li 3 BO 3 to _{Li 2 SO 4, Li 2 CO} 3, Li 4 amorphous Shitsujo or crystalline mixed one or two kinds or more of SiO ₄ comprising material group _11. The electrode member according to claim 10, wherein the electrode member is selected from one or more of the group consisting of: Li _1.3 Al _0.3 Ti _1.7 P ₃ O ₁₂ and Li _0.33 La _0.55 TiO ₃ . The electrode member according to claim 10, wherein the powder made of the oxide-based solid electrolyte has a 50% particle size (D ₅₀ ) of 10 μm or less in a cumulative particle size distribution on a volume basis.   The electrode member according to any one of claims 10 to 12, wherein the mixture contains 25 to 99% by mass of a powder made of the oxide-based solid electrolyte.