JP2013163621A - Oxide-ion-conductive oxide nanosheet, manufacturing method for oxide-ion-conductive oxide nanosheet, and electrolyte for solid-oxide fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new oxide-ion-conductive oxide nanosheet, a manufacturing method for the oxide-ion-conductive oxide nanosheet, and an electrolyte for a solid-oxide fuel cell made of the oxide-ion-conductive oxide nanosheet.SOLUTION: A manufacturing method for an oxide-ion-conductive oxide nanosheet includes: a step 1 for preparing a raw material solution that contains a raw salt of the oxide-ion-conductive oxide, a pH adjuster, and a layer-forming additive for forming a precursor of the oxide-ion-conductive oxide nanosheet from the raw salt of the oxide-ion-conductive oxide and the pH adjuster; a step 2 following the step 1 for agitating and mixing the prepared raw material solution to form the precursor of the oxide-ion-conductive oxide nanosheet; and a step 3 following the step 2 for isolating the oxide-ion-conductive oxide nanosheet from the formed precursor of the oxide-ion-conductive oxide nanosheet.

Description

The present invention relates to an oxide ion conductive oxide nanosheet, a method for producing an oxide ion conductive oxide nanosheet, and an electrolyte for a solid oxide fuel cell.
More specifically, the present invention relates to a novel oxide ion conductive oxide nanosheet, a method for producing an oxide ion conductive oxide nanosheet, and a solid oxide fuel cell using the oxide ion conductive oxide nanosheet. It relates to electrolytes.

  Conventionally, when mass-producing zirconia sheets for use as fuel cell electrolytes, zirconia green sheets are produced using zirconia particles having an average particle size of about 0.1 μm and a 90% by volume particle size of about 0.44 μm. In addition, it has been proposed to perform the degreasing step of the zirconia green sheet in an atmosphere having an oxygen concentration of 13% or more to obtain a zirconia sheet having a thickness of 150 μm (see Patent Document 1).

JP 2007-55862 A

However, the zirconia sheet described in Patent Document 1 has a problem that the thickness of the zirconia sheet is increased due to the size of the raw material.
Further, in the study by the present inventors, it has been found that when the thickness of the zirconia sheet is simply reduced, the airtightness of the zirconia sheet obtained due to the shape of the raw material may be lowered.

The present invention has been made in view of such problems of the prior art.
The object of the present invention is a novel oxide ion conductive oxide nanosheet, a method for producing an oxide ion conductive oxide nanosheet, and a solid oxide fuel using the oxide ion conductive oxide nanosheet The object is to provide an electrolyte for a battery.

The inventors of the present invention have made extensive studies in order to achieve the above object.
As a result, a predetermined raw material-containing liquid is prepared, and the raw material-containing liquid is stirred and mixed to form an oxide ion conductive oxide nanosheet precursor. The present inventors have found that the above object can be achieved by, for example, fractionating oxide ion conductive oxide nanosheets, and have completed the present invention.

That is, the manufacturing method of the oxide ion conductive oxide nanosheet of the present invention is a manufacturing method including the following (Step 1) to (Step 3).
(Step 1): Forming an oxide ion conductive oxide nanosheet precursor from an oxide ion conductive oxide raw material salt, a pH adjuster, the oxide ion conductive oxide raw material salt, and the pH adjuster. Step of preparing a raw material-containing liquid containing a layer forming additive for the above (Step 2): Conducting after the above (Step 1), stirring and mixing the prepared raw material-containing liquid, oxide ion conductivity Step of forming oxide nanosheet precursor (step 3): performed after the above (step 2), and separating the oxide ion conductive oxide nanosheet from the formed oxide ion conductive oxide nanosheet precursor Process

  Moreover, the oxide ion conductive oxide nanosheet of this invention is obtained by the manufacturing method of the oxide ion conductive oxide nanosheet of the said invention.

  Furthermore, the solid oxide fuel cell electrolyte of the present invention is formed using the oxide ion conductive oxide nanosheet of the present invention.

According to the present invention, a predetermined raw material-containing liquid is prepared, the raw material-containing liquid is stirred and mixed to form an oxide ion conductive oxide nanosheet precursor, and novel from the oxide ion conductive oxide nanosheet precursor The oxide ion conductive oxide nanosheet was fractionated.
Therefore, it is possible to provide a novel oxide ion conductive oxide nanosheet, a method for producing an oxide ion conductive oxide nanosheet, and an electrolyte for a solid oxide fuel cell using the oxide ion conductive oxide nanosheet. .

It is a figure (a) and (b) explaining the interlayer distance in an oxide ion conductive oxide lamination nanosheet. It is a graph which shows the result of the X-ray diffraction analysis which shows the interlayer distance in an oxide ion conductive oxide lamination | stacking nanosheet. It is a figure (a) and (b) explaining the shape of an oxide ion conductive oxide laminated nanosheet and a single layer nanosheet. It is a scanning electron micrograph of a zirconium oxide laminated nanosheet. It is a scanning electron micrograph (a) and (b) of a zirconium oxide single layer nanosheet. It is a result of the atomic force microscope analysis which shows the film thickness in a zirconium oxide single layer nanosheet. It is sectional drawing which shows some examples of the electrolyte for solid oxide fuel cells. It is a top view which shows some examples of the electrolyte for solid oxide fuel cells.

Hereinafter, an oxide ion conductive oxide nanosheet according to an embodiment of the present invention, a method for producing an oxide ion conductive oxide nanosheet, and an electrolyte for a solid oxide fuel cell using the oxide ion conductive oxide nanosheet Will be described in detail.
In the present invention, the term “oxide ion conductive oxide nanosheet” should not be interpreted to include not only a single layer structure but also a layered structure composed of a single layer structure. Don't be. In the present invention, a single layer structure may be referred to as “oxide ion conductive oxide single layer nanosheet” or simply “single layer nanosheet”, and a layered structure may be referred to as “oxide ion conductive”. Oxidized oxide laminated nanosheet "or simply" laminated nanosheet ".

  First, the manufacturing method of the oxide ion conductive oxide nanosheet which concerns on one Embodiment of this invention is demonstrated in detail.

<First Embodiment>
The manufacturing method of the oxide ion conductive oxide nanosheet which concerns on this embodiment includes the following (process 1)-(process 3). By passing through such a process, the predetermined oxide ion conductive oxide nanosheet described in detail below can be obtained. In addition, since the oxide ion conductive oxide nanosheet can be used for film formation on the electrode after having been finalized in advance, it can reduce damage to the electrode due to the use of acid or base during production. There is a secondary advantage of being able to. In addition, the film can be formed at a low temperature, and there is a secondary advantage that the cost can be reduced, for example, a metal material or a ceramic material applied in combination can be replaced with an inexpensive material.

(Step 1): Forming an oxide ion conductive oxide nanosheet precursor from an oxide ion conductive oxide raw material salt, a pH adjuster, the oxide ion conductive oxide raw material salt, and the pH adjuster. Step of preparing a raw material-containing liquid containing a layer forming additive for the above (Step 2): Conducting after the above (Step 1), stirring and mixing the prepared raw material-containing liquid, oxide ion conductivity Step of forming oxide nanosheet precursor (step 3): performed after the above (step 2), and separating the oxide ion conductive oxide nanosheet from the formed oxide ion conductive oxide nanosheet precursor Process

  Hereinafter, each of (Step 1) to (Step 3) will be described in more detail.

(Process 1)
In step 1, for example, the following predetermined oxide ion conductive oxide raw material salt, pH adjuster and layer forming additive may be weighed and put into an appropriate amount of dispersion medium to prepare a raw material-containing liquid. Examples of the dispersion medium include water. Further, for example, a pH adjuster may be added to the raw material-containing liquid so that the pH of the raw material-containing liquid is about 7-8. Furthermore, at present, it is estimated that the oxide ion conductive oxide raw material salt and the layer forming additive form a complex to form the oxide ion conductive oxide nanosheet precursor, so that the molar equivalent is about These may be added so that In order to examine complex formation, the amount of sodium dodecyl sulfate as an additive for layer formation was changed to 1 to 10 mol with respect to 1 mol of zirconium chloride octahydrate as an oxide ion conductive oxide raw material salt. The degree of crystallinity and production of zirconium oxide nanosheets were investigated, but no particular difference could be observed. Therefore, in this case, if a molar equivalent amount of sodium dodecyl sulfate is mixed with zirconium chloride oxide octahydrate, the target oxide ion conductive oxide nanosheet can be obtained. The oxide ion conductive oxide nanosheet is dispersed in a dispersion medium, and is obtained by separating and drying the supernatant of the dispersion medium. Therefore, the concentration of the oxide ion conductive oxide raw material salt and the layer forming additive may be higher than the saturation concentration.

  The oxide ion conductive oxide raw material salt to be used may be appropriately selected according to the target oxide ion conductive oxide. For example, when obtaining zirconium oxide as an oxide ion conductive oxide, a chlorinated zirconium oxide salt can be preferably used. Further, for example, when obtaining zirconium oxide stabilized as at least one of scandium oxide and yttrium oxide as an oxide ion conductive oxide, at least one of chlorinated zirconium oxide salt and chlorinated yttrium oxide salt and chloride A salt related to a combination with a zirconium oxide salt can be preferably used. In addition, what is necessary is just to adjust these compounding quantities according to the composition of the target oxide, when combining several salt.

  As a pH adjuster to be used, what can adjust the pH of a raw material containing liquid to 7-8 can be mentioned, for example. For example, a base containing hexamethyltetramine or aqueous ammonia can be used. Hexamethyltetramine and aqueous ammonia may be used alone or in combination.

  Examples of the layer forming additive to be used include those capable of forming a layer structure (single layer or laminated layer) of the oxide ion conductive oxide nanosheet precursor from the raw material-containing liquid. For example, dodecyl sulfate containing an alkali metal such as lithium, sodium, or potassium, or an alkaline earth metal such as magnesium or calcium can be used. Alkali metal dodecyl sulfate and alkaline earth metal dodecyl sulfate may be used alone or in combination.

(Process 2)
In step 2, the raw material-containing liquid is stirred and mixed to form an oxide ion conductive oxide nanosheet precursor. At present, it is assumed that such a precursor is a complex salt formed by the oxide ion conductive oxide raw material salt and the layer forming additive. The conditions for stirring and mixing may be a temperature of the dispersion medium of 80 to 100 ° C., a stirring speed of the magnetic stirrer of 150 to 200 rpm, and stirring and mixing for 10 to 12 hours. At this time, it is preferable that the oxide ion conductive oxide raw material salt and the layer forming additive are completely dissolved. However, the present invention is not limited to this, and a part thereof may remain undissolved. . Further, the generated oxide ion conductive oxide nanosheet precursor is either when the oxide ion conductive oxide raw material salt and the layer forming additive are completely dissolved or not dissolved. Is also dissolved in the liquid.

(Process 3)
In step 3, the oxide ion conductive oxide nanosheet may be separated from the oxide ion conductive oxide nanosheet precursor. When fractionating, the oxide ion conductive oxide nanosheet can be obtained by fractionating and drying the stirred and mixed solution or the supernatant solution thereof. The oxide ion conductive oxide nanosheet obtained at this time is mainly composed of laminated nanosheets. Moreover, the conditions at the time of fractionation should just make an atmospheric temperature 60-60 degreeC, and make it dry for 20 to 24 hours.
In the present invention, “mainly composed of laminated nanosheets” refers to those having a thickness of 10 nm or more. In addition, in the laminated nanosheet, the length in the sheet thickness direction of the single-layer nanosheet constituting the laminated nanosheet is preferably 1 nm to 10 nm, and the length of the shortest portion in the sheet surface direction of the single-layer nanosheet is preferably 1 μm or more.

<Second Embodiment>
The manufacturing method of the oxide ion conductive oxide nanosheet which concerns on this embodiment includes the said (process 1)-(process 3), and also the following (process 4)-(process 6). By passing through such a process, the predetermined oxide ion conductive oxide nanosheet described in detail below can be obtained.

(Step 4): composed of the oxide ion conductive oxide nanosheet that is implemented after the above (Step 3), and may be included in the oxide ion conductive oxide nanosheet, and is configured by the oxide ion conductive oxide nanosheet Step of preparing an oxide ion conductive oxide nanosheet-containing liquid containing an interlayer distance increasing additive for increasing the interlayer distance in the laminated nanosheet to be performed (Step 5): carried out after the above (Step 4), the above preparation Agitating and mixing the prepared oxide ion conductive oxide nanosheet-containing liquid to increase the interlayer distance of the laminated nanosheet composed of single-layer nanosheets that may be included in the oxide ion conductive oxide nanosheet-containing liquid (Step 6): A step of separating the formed oxide ion conductive oxide nanosheet formed after the above (Step 5).

  Hereinafter, each (Step 4) to (Step 6) will be described in more detail.

(Process 4)
In step 4, the interlayer distance in the laminated nanosheet composed of the sorted oxide ion conductive oxide nanosheet and a single layer nanosheet that may be included in the oxide ion conductive oxide nanosheet is expanded. What is necessary is just to prepare the oxide ion conductive oxide nanosheet containing liquid containing the interlayer distance expansion additive. Since the predetermined oxide ion conductive oxide nanosheet is dispersed in the dispersion medium, it can be obtained by drying the supernatant in the dispersion medium. Accordingly, the ratio between the dispersion medium such as water and the powdered oxide ion conductive oxide nanosheet is not particularly limited, but should be set so as not to precipitate during the stirring and mixing described in detail below. Is preferred. Moreover, what is necessary is just to add the additive for interlayer distance expansion so that it may become a molar equivalent grade with respect to an oxide ion conductive oxide single layer nanosheet.

  FIG. 1 is a diagram (a) and (b) illustrating an interlayer distance in an oxide ion conductive oxide laminated nanosheet. As shown in FIG. 2A, the laminated nanosheet 4 has a structure in which a plurality of single-layer nanosheets 2 are laminated. When the additive for increasing the interlayer distance is added, the interlayer distance d of the single-layer nanosheet 2 constituting the laminated nanosheet 4 is increased (see FIG. 5B).

  FIG. 2 is a graph showing the results of X-ray diffraction analysis (XRD) of an oxide ion conductive oxide (zirconium oxide) laminated nanosheet. As shown in the figure, the interlayer distance increasing additive is compared with the case of (b) in which 0.01 mol / L tetrabutylammonium was added as the interlayer distance increasing additive in an amount of 0.01 mol / (laminated nanosheet 1 g). In the case of (a) in which 0.1 mol / L of sodium oleate aqueous solution of 0.1 mol / L was added as (a), the peak derived from the interlayer distance d detected by XRD was shifted, and the interlayer distance It can be seen that d is enlarged. Further, when the layers of the laminated nanosheet described in detail below are peeled from each other, a monolayer nanosheet having a proportionally large sheet area tends to be obtained by increasing the interlayer distance in advance (FIG. 5). reference.). That is, the size of the oxide ion conductive oxide nanosheet, in particular, the oxide ion conductive oxide single layer nanosheet can be controlled by appropriately changing the type of the interlayer distance increasing additive, the stirring conditions, and the like.

  Examples of the interlayer distance increasing additive to be used include those capable of expanding the interlayer distance in the laminated nanosheet. For example, an alcohol having 4 or more carbon atoms such as 1-butanol, an alkali metal oleate containing an alkali metal such as lithium, sodium or potassium, or an alkaline earth metal oleate containing an alkaline earth metal such as magnesium or calcium Examples thereof include salts, formaldehyde, and tetrabutylammonium. These can be used singly or in appropriate combination of two or more. Moreover, it is not limited to these, For example, C10-C18 long-chain alkyl alcohol etc. can also be applied.

(Process 5)
In step 5, when the oxide ion conductive oxide nanosheet-containing liquid is stirred and mixed and the laminated nanosheet is included in the oxide ion conductive oxide nanosheet-containing liquid, the interlayer distance of the laminated nanosheet is increased. Just do it. The conditions for stirring and mixing are: the temperature of the dispersion medium is room temperature (20 ° C.) to 80 ° C., preferably room temperature (20 ° C.), the stirring speed of the magnetic stirrer is 100 to 500 rpm, preferably 500 rpm, and 24 to 72 hours. Preferably, stirring and mixing may be performed for 72 hours. At this time, the oxide ion conductive oxide nanosheet is dispersed in a solid state in the liquid.

(Step 6)
In step 6, the oxide ion conductive oxide nanosheet may be separated from the oxide ion conductive oxide nanosheet-containing liquid. When fractionating, the solid content in the stirred and mixed liquid is collected by filtration, washed twice with distilled water, further washed twice with ethanol, and dried to obtain an oxide ion conductive oxide nanosheet. Can be obtained. The oxide ion conductive oxide nanosheet obtained at this time is mainly composed of laminated nanosheets. Moreover, in order to fractionate, the atmospheric temperature may be 60-100 degreeC, and what is necessary is just to dry for 20-24 hours.

<Third Embodiment>
The manufacturing method of the oxide ion conductive oxide nanosheet according to the present embodiment includes the above (Step 1) to (Step 3), the following (Step 7) to (Step 9), and the above (Step 4) as necessary. ) To (Step 6). By passing through such a process, the predetermined oxide ion conductive oxide nanosheet mentioned later in detail can be obtained.

(Step 7): The fractionated oxide ions that are carried out after (Step 6) and / or after (Step 3) and before (Step 4). Oxide ion conductivity comprising a conductive oxide nanosheet and a layer peeling additive for peeling layers from each other in a laminated nanosheet composed of a single layer nanosheet that may be contained in the oxide ion conductive oxide nanosheet Step of preparing oxide nanosheet-containing liquid (step 8): performed after the above (step 7) and / or after the above (step 7) and before the above (step 4) The above-prepared oxide ion conductive oxide nanosheet-containing liquid is stirred and mixed to form a multilayer nanosheet composed of single-layer nanosheets that may be included in the oxide ion conductive oxide nanosheet-containing liquid. Step (Step 9): Performed after the above (Step 8) and / or after the above (Step 8) and before the above (Step 4). Process for fractionating ion-conductive oxide nanosheets

(Step 7)
In step 7, the layers in the laminated nanosheet composed of the sorted oxide ion conductive oxide nanosheet and a single layer nanosheet that may be included in the oxide ion conductive oxide nanosheet are separated from each other. What is necessary is just to prepare the oxide ion conductive oxide nanosheet containing liquid containing the additive for layer peeling. At this time, the ratio of the dispersion medium such as water and the powdered oxide ion conductive oxide nanosheet is not particularly limited, but does not precipitate during stirring and mixing described in detail below. It is preferable. Moreover, what is necessary is just to add the additive for layer peeling so that it may become a molar equivalent grade with respect to an oxide ion conductive oxide single layer nanosheet.

  Examples of the layer peeling additive to be used include those capable of peeling the layers in the laminated nanosheet when the oxide ion conductive oxide nanosheet includes the laminated nanosheet. For example, for example, an alcohol having 4 or more carbon atoms such as 1-butanol, an alkali metal oleate containing an alkali metal such as lithium, sodium or potassium, or an alkali earth oleate containing an alkaline earth metal such as magnesium or calcium Metal salts, formaldehyde, tetrabutylammonium and the like. These can be used singly or in appropriate combination of two or more. Moreover, it is not limited to these, For example, C10-C18 long-chain alkyl alcohol etc. can also be applied.

(Process 8)
In step 8, when the oxide ion conductive oxide nanosheet-containing liquid is stirred and mixed, and the laminated nanosheet is included in the oxide ion conductive oxide nanosheet-containing liquid, the laminated nanosheet is regarded as a single-layer nanosheet. That's fine. The conditions for stirring and mixing are: the temperature of the dispersion medium is room temperature (20 ° C.) to 100 ° C., preferably 60 to 80 ° C., the stirring speed of the magnetic stirrer is 100 to 200 rpm, and 5 days to 10 days, preferably 7 What is necessary is just to stir and mix for days. At this time, the oxide ion conductive oxide nanosheet is dispersed in a solid state in the liquid.

(Step 9)
In step 9, the oxide ion conductive oxide nanosheet may be separated from the oxide ion conductive oxide nanosheet-containing liquid. At the time of fractionation, an oxide ion conductive oxide nanosheet can be obtained by separating and stirring the mixed liquid at a speed of 3000 to 5000 rpm and taking 10 to 30 minutes. The oxide ion conductive oxide nanosheet obtained at this time is mainly composed of a single-layer nanosheet. In addition, the conditions for fractionation are as follows: after centrifugation, if the precipitate is a single layer, the entire layer is separated if it is a double layer, and the ambient temperature is 60-100 ° C. What is necessary is just to dry for 24 hours.
In the present invention, “mainly composed of single-layer nanosheets” refers to those having a thickness of 1 nm to 10 nm in the sheet thickness direction. The reason why the upper layer is separated is because the bulk density of the precipitate made of the single layer nanosheet is larger than that of the precipitate made of the laminated nanosheet. Moreover, this single-layer nanosheet preferably has a length of the shortest portion in the sheet surface direction of 1 μm or more.

  Further, when the layers of the laminated nanosheet described in detail above are peeled from each other, the oxide ion conductive oxide nanosheet, in particular, the oxide ion conduction, is appropriately changed by appropriately changing the type of the layer peeling additive and the stirring condition. The size of the conductive oxide single layer nanosheet can be controlled.

  Next, the oxide ion conductive oxide nanosheet which concerns on one Embodiment of this invention is demonstrated in detail.

<Fourth Embodiment>
The oxide ion conductive oxide nanosheet which concerns on this embodiment is obtained by the manufacturing method of the oxide ion conductive oxide nanosheet which concerns on one Embodiment of this invention which was mentioned above. Moreover, the material of such an oxide ion conductive oxide nanosheet can be, for example, zirconium oxide or zirconium oxide stabilized with at least one of scandium oxide and yttrium oxide.

  FIGS. 3A and 3B are diagrams (a) and (b) illustrating shapes of oxide ion conductive oxide laminated nanosheets and single-layer nanosheets. As shown in FIG. 3, the oxide ion conductive oxide nanosheet 1 is composed of a laminated nanosheet 4 (see FIG. 3A) or a single-layer nanosheet 2 (see FIG. 3B). There is. The laminated nanosheet 4 has a structure in which a plurality of single-layer nanosheets 2 are laminated, and the shape of the single-layer nanosheet 2 is 1 nm to 10 nm in length (thickness) in the sheet thickness direction. The length of the shortest portion in the sheet surface direction, which is a direction perpendicular to the sheet surface, is 1 μm or more (see FIG. 5B).

  FIG. 4 is a scanning electron micrograph of the zirconium oxide laminated nanosheet. FIG. 5 (a) is a scanning electron micrograph of a zirconium oxide single-layer nanosheet when sodium oleate is used as the layer peeling additive, and FIG. 5 (b) is a layer peeling additive. It is a scanning electron micrograph of a zirconium oxide single layer nanosheet when tetrabutylammonium is used. Further, FIG. 6 is a graph showing the results of atomic force microscope analysis showing the thickness of the zirconium oxide single-layer nanosheet when tetrabutylammonium is used as the layer peeling additive. FIG. 6 shows that the thickness of the zirconium oxide single-layer nanosheet is about 3 nm.

  Next, a solid oxide fuel cell electrolyte according to an embodiment of the present invention will be described in detail.

<Fifth Embodiment>
The solid oxide fuel cell electrolyte according to this embodiment is formed using the oxide ion conductive oxide nanosheet according to one embodiment of the present invention as described above.
Such an electrolyte for a solid oxide fuel cell has a porous electrode applied as a fuel electrode or an air electrode of a solid oxide fuel cell, and the open pores in other electrolytes are blocked with an oxide ion conductive oxide nanosheet. Can be made. That is, since the thickness can be reduced while the electrolyte is excellent in airtightness, an electrolyte having excellent oxide ion conductivity and airtightness can be formed.

  Hereinafter, some examples of the solid oxide fuel cell electrolyte of the present embodiment will be described in detail with reference to the drawings.

FIG. 7 is a cross-sectional view showing some examples of an electrolyte for a solid oxide fuel cell. FIG. 8 is a plan view showing some examples of the electrolyte for a solid oxide fuel cell (except for the example shown in FIG. 7B).
As shown in FIG. 7A, the solid oxide fuel cell electrolyte 10 of this example is formed on the porous electrode 20 of the solid oxide fuel cell. Further, the solid oxide fuel cell electrolyte 10 is an electrolyte for a solid oxide fuel cell formed using an yttrium oxide-stabilized zirconium oxide single layer nanosheet which is an example of an oxide ion conductive oxide single layer nanosheet. 10a. Moreover, as shown in FIG. 8, since the pore diameter D of the open pores of the porous electrode 20 is about 1 to 5 μm, the length of the shortest portion in the sheet surface direction of the oxide ion conductive oxide single-layer nanosheet 2 Is preferably longer than its length. At this time, the open pores are more reliably closed by the oxide ion conductive oxide single layer nanosheet 2. In addition, such a solid oxide fuel cell electrolyte is obtained by applying a single-layer nanosheet-containing liquid on a porous electrode, drying, repeating these steps as necessary, and firing at 500 to 800 ° C. Can be formed. Although not shown in the figure, the electrolyte may be laminated with single-layer nanosheets, and the number of layers can be controlled by applying the layered nanosheets in advance, or by appropriately changing conditions such as the number of coatings and the amount of coating. it can.

  As shown in FIG. 7 (b), the solid oxide fuel cell electrolyte 10 'of this example is formed on the porous electrode 20 of the solid oxide fuel cell. The solid oxide fuel cell electrolyte 10 ′ is a solid formed on the porous electrode 20 side using an yttrium oxide-stabilized zirconium oxide single layer nanosheet which is an example of an oxide ion conductive oxide single layer nanosheet. Electrode deposition film for solid oxide fuel cell formed thereon by DC magnetron sputtering using oxide electrolyte fuel cell electrolyte 10a and yttrium oxide-stabilized zirconium oxide at room temperature in an argon / oxygen gas supply atmosphere 10b. In addition, the solid oxide fuel cell electrolyte 10 'of this example is a single layer as compared to the case where the solid oxide fuel cell electrolyte having the same thickness is formed of only the solid oxide fuel cell electrolyte 10a. There is an advantage that the interfacial resistance of the nanosheet can be reduced and the power generation performance is improved. In addition, since the pore diameter D of the open pores of the porous electrode 20 is about 1 to 5 μm, the length of the shortest portion in the sheet surface direction of the oxide ion conductive oxide single layer nanosheet 2 may be longer than that length. preferable. At this time, the open pores are more reliably closed by the oxide ion conductive oxide single layer nanosheet 2. In addition, such a solid oxide fuel cell electrolyte is obtained by applying a single-layer nanosheet-containing liquid on a porous electrode, drying, repeating these steps as necessary, and further firing at 500 to 800 ° C. Thereafter, it can be formed by DC magnetron sputtering using yttrium oxide stabilized zirconium oxide at room temperature in an argon / oxygen gas supply atmosphere. Although not shown in the figure, the electrolyte may be laminated with single-layer nanosheets, and the number of layers can be controlled by applying the layered nanosheets in advance, or by appropriately changing conditions such as the number of coatings and the amount of coating. it can. The thickness of the deposited film can be controlled by appropriately changing the sputtering time.

As shown in FIGS. 7C to 7F, the solid oxide fuel cell electrolytes (10 ″, 10 ′ ″, 10 ″ ″, 10 ′ ″ ″) of the respective examples are as follows. It is formed on the porous electrode 20 of the solid oxide fuel cell or the electrolyte vapor deposition film 10b for the solid oxide fuel cell. The solid oxide fuel cell electrolyte in each example (10 ″, 10 ′ ″, 10 ″ ″, 10 ′ ″ ″) is an example of an oxide ion conductive oxide single layer nanosheet. DC magnetron using solid oxide fuel cell electrolyte 10a formed using yttrium oxide-stabilized zirconium oxide single-layer nanosheets and yttrium oxide-stabilized zirconium oxide at room temperature in an argon / oxygen gas supply atmosphere It consists of the solid oxide fuel cell electrolyte deposition film 10b formed by sputtering. Each example is different only in the stacking order, etc., and the specifications and formation method of each solid oxide fuel cell electrolyte and the specifications of the porous electrode are the same as described above, and therefore detailed Description is omitted.
Although not shown, the number of alternating layers can be two or more.

Further, from the viewpoint of airtightness in the solid oxide fuel cell electrolyte, the solid oxide fuel cell electrolyte is an example of an oxide ion conductive oxide single layer nanosheet on the surface facing the porous electrode. Yttrium oxide It is preferable that the electrolyte for solid oxide fuel cells formed using the stabilized zirconium oxide single-layer nanosheet is located.
Furthermore, when the vapor deposition film is formed on the porous electrode first, the pore diameter of the open pores can be set to about 1 μm, so that the pore diameter of the open pores is formed on the porous electrode of 1 to 5 μm and In comparison, there is an advantage that the open pores are easily closed by the oxide ion conductive oxide single layer nanosheet.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
About 150 mL of ion-exchanged water, zirconium chloride octahydrate (1 mmol) as a raw material salt of an oxide ion conductive oxide, hexamethylenetetramine (6 mmol) as a pH adjuster, and a layer forming additive As a raw material containing liquid, sodium dodecyl sulfate (10 mmol) was added. At this time, the pH of the raw material-containing liquid was 7.9. Next, the prepared raw material-containing liquid is stirred at a temperature of 100 ° C. using a hot plate and stirred at a speed of 200 rpm using a magnetic stirrer for 12 hours to form a zirconium oxide nanosheet precursor. did. Thereafter, the solution portion was collected and dried at 60 ° C. for 24 hours to obtain a zirconium oxide nanosheet (laminated nanosheet). In addition, the length (thickness) in the sheet thickness direction in the single-layer nanosheet constituting the laminated nanosheet was 5 nm, and the length of the shortest portion in the sheet surface direction, which is a direction perpendicular to the thickness, was 20 μm.

(Example 2)
A solution containing about 10 mL of ion-exchange water containing 0.1 g of the zirconium oxide nanosheet (laminated nanosheet) powder obtained in Example 1, and 0.1 mol / L sodium oleate as an additive for increasing the interlayer distance An aqueous solution (100 mL) was added to prepare a zirconium oxide nanosheet-containing liquid. Next, the prepared zirconium oxide nanosheet-containing liquid is brought to room temperature (25 ° C.), and stirred and mixed for 72 hours in a state where the stirring speed is 500 rpm using a magnetic stirrer, and the interlayer distance of the zirconium oxide nanosheet (laminated nanosheet) Was expanded. Further, the solid content was collected by filtration and washed twice with distilled water and ethanol. Thereafter, it was dried at 60 ° C. for 24 hours to obtain a zirconium oxide nanosheet (laminated nanosheet). In addition, the length (thickness) in the sheet thickness direction in the single-layer nanosheet constituting the laminated nanosheet was 3 nm, and the length of the shortest portion in the sheet surface direction, which is a direction perpendicular to the thickness, was 3 μm.

(Example 3)
A solution containing 0.1 g of the zirconium oxide nanosheet (laminated nanosheet) powder obtained in Example 2 in about 10 mL of ion-exchanged water and 1-butanol (100 mL) as an additive for delamination were added. Thus, a zirconium oxide nanosheet-containing liquid was prepared. Next, the prepared zirconium oxide nanosheet-containing liquid was stirred and mixed for 2 weeks in a state where the temperature was set to 80 ° C. using a hot plate and the stirring speed was set to 100 rpm using a magnetic stirrer, and the zirconium oxide nanosheet (laminated) Nanosheets) were separated from each other. Further, centrifugation was performed for 10 minutes using a centrifugal separator at a rotational speed of 5000 rpm. Thereafter, the precipitate (single layer) was collected to obtain a zirconium oxide nanosheet (single-layer nanosheet). The length (thickness) in the sheet thickness direction of the single-layer nanosheet was 3 nm, and the length of the shortest portion in the sheet surface direction, which is a direction perpendicular to the thickness, was 3 μm.

  As mentioned above, although this invention was demonstrated with some embodiment and an Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.

  For example, the configuration described in each of the above-described embodiments and examples is not limited to each embodiment. For example, an oxide ion conductive oxide raw material salt, a pH adjuster, an interlayer distance expansion addition The details of the composition such as the agent and the layer peeling additive can be changed.

  Further, for example, in each of the embodiments and examples described above, the case where the oxide ion conductive oxide is used as an electrolyte for a solid oxide fuel cell has been described as an example. For example, 8 mol% yttrium oxide-stabilized zirconium oxide (8YSZ) or scandium oxide-stabilized zirconia oxide (SSZ) can be applied to an electrolyte in an oxygen separation membrane or an oxygen sensor.

  Furthermore, for example, in each of the above-described embodiments and examples, description has been made by paying attention to oxide ion conductivity such as zirconium oxide. It becomes a single-layer or multi-layer nanosheet that contributes to more precisely controlling the performance of the applied product, such as the rate, the strength of the blade, the insulation / resistance of the electrical element, and the like. For example, 3 mol% yttrium oxide stabilized zirconium oxide (3YSZ) can be used as a strength material having excellent toughness and strength.

DESCRIPTION OF SYMBOLS 1 ... Oxide ion conductive oxide nanosheet, 2 ... Single layer nanosheet, 4 ... Laminated nanosheet 10, 10, 10 ', 10'',10''', 10 '''', 10 '''''... Solid Electrolyte fuel cell electrolyte, 10a ... Solid electrolyte fuel cell electrolyte formed using oxide ion conductive oxide nanosheet, 10b ... Solid electrolyte fuel cell electrolyte deposition film, 20 ... Porous electrode, Pore size ... D

Claims (14)

A method for producing an oxide ion conductive oxide nanosheet,
The following (Step 1) to (Step 3)
(Step 1): Forming an oxide ion conductive oxide nanosheet precursor from an oxide ion conductive oxide raw material salt, a pH adjuster, the oxide ion conductive oxide raw material salt, and the pH adjuster. Step of preparing a raw material-containing liquid containing a layer forming additive for the above (Step 2): Conducting after the above (Step 1), stirring and mixing the prepared raw material-containing liquid, oxide ion conductivity Step of forming oxide nanosheet precursor (step 3): performed after the above (step 2), and separating the oxide ion conductive oxide nanosheet from the formed oxide ion conductive oxide nanosheet precursor The manufacturing method of the oxide ion conductive oxide nanosheet characterized by including the process to do. The following (Step 4) to (Step 6)
(Step 4): composed of the oxide ion conductive oxide nanosheet that is implemented after the above (Step 3), and may be included in the oxide ion conductive oxide nanosheet, and is configured by the oxide ion conductive oxide nanosheet Step of preparing an oxide ion conductive oxide nanosheet-containing liquid containing an interlayer distance increasing additive for increasing the interlayer distance in the laminated nanosheet to be performed (Step 5): carried out after the above (Step 4), the above preparation Agitating and mixing the prepared oxide ion conductive oxide nanosheet-containing liquid to increase the interlayer distance of the laminated nanosheet composed of single-layer nanosheets that may be included in the oxide ion conductive oxide nanosheet-containing liquid (Step 6): It is carried out after the above (Step 5), and further includes a step of separating the formed oxide ion conductive oxide nanosheet. Method of manufacturing an oxide ion conductive oxide nanosheets according to claim 1 that. Following (Step 7) to (Step 9)
(Step 7): The fractionated oxide ions that are carried out after (Step 6) and / or after (Step 3) and before (Step 4). Oxide ion conductivity comprising a conductive oxide nanosheet and a layer peeling additive for peeling layers from each other in a laminated nanosheet composed of a single layer nanosheet that may be contained in the oxide ion conductive oxide nanosheet Step of preparing oxide nanosheet-containing liquid (step 8): performed after the above (step 7) and / or after the above (step 7) and before the above (step 4) The prepared oxide ion conductive oxide nanosheet-containing liquid is stirred and mixed to form a laminated nanosheet composed of single-layer nanosheets that may be contained in the oxide ion conductive oxide nanosheet-containing liquid. Step (Step 9): Performed after the above (Step 8) and / or after the above (Step 8) and before the above (Step 4). The method for producing an oxide ion conductive oxide nanosheet according to claim 1, further comprising a step of separating the oxide ion conductive oxide nanosheet.   The single-layer nanosheet constituting the laminated nanosheet or the length of the single-layer nanosheet in the sheet thickness direction is 1 nm to 10 nm, and the length of the shortest portion in the sheet surface direction is 1 μm or more. 4. The method for producing an oxide ion conductive oxide nanosheet according to any one of 3 above.   The oxide oxide conductive oxide is zirconium oxide or zirconium oxide stabilized by at least one of scandium oxide and yttrium oxide, according to any one of claims 1 to 4. Manufacturing method of oxide ion conductive oxide nanosheet.   2. The oxide ion conductive oxide raw material salt is a salt relating to a chlorinated zirconium oxide salt, or a combination of at least one of a chlorinated scandium oxide salt and a chlorinated yttrium oxide salt and a chlorinated zirconium oxide salt. The manufacturing method of the oxide ion conductive oxide nanosheet of any one term of 1-5.   The said pH adjuster is a base containing hexamethyltetramine and / or ammonia water, The manufacturing method of the oxide ion conductive oxide nanosheet of any one of Claims 1-6 characterized by the above-mentioned.   The oxide ion conductive oxide according to any one of claims 1 to 7, wherein the layer forming additive is dodecyl sulfate containing an alkali metal and / or an alkaline earth metal. Manufacturing method of nanosheet.   The interlayer distance increasing additive is at least one selected from the group consisting of alcohols having 4 or more carbon atoms, alkali metal oleates, alkaline earth metal oleates, formaldehyde, and tetrabutylammonium. The manufacturing method of the oxide ion conductive oxide nanosheet as described in any one of Claims 2-8.   The layer peeling additive is at least one selected from the group consisting of alcohols having 4 or more carbon atoms, alkali metal oleates, alkaline earth metal oleates, formaldehyde, and tetrabutylammonium. The manufacturing method of the oxide ion conductive oxide nanosheet of any one of Claims 3-9 to do.   The oxide ion conductive oxide nanosheet obtained by the manufacturing method of the oxide ion conductive oxide nanosheet of any one of Claims 1-10.   The single-layer nanosheet and / or the single-layer nanosheet constituting the laminated nanosheet has a length in the sheet thickness direction of 1 nm to 10 nm, and the length of the shortest portion in the sheet surface direction is 1 μm or more. Ion conductive oxide nanosheet.   The oxide ion conductive oxide nanosheet according to claim 12, wherein the oxide ion conductive oxide is zirconium oxide or zirconium oxide stabilized by at least one of scandium oxide and yttrium oxide. .   An electrolyte for a solid oxide fuel cell, which is formed using the oxide ion conductive oxide nanosheet according to any one of claims 11 to 13.

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