JPWO2019235025A1 - Proton conductor and electrochemical device using it - Google Patents

Abstract

It has a perovskite-type structure and has the following formula (1): AxB1-yMyO3-δ (where element A is at least one selected from the group consisting of Ba, Ca and Sr, and element B is Ce and Zr. The element M is at least one selected from the group consisting of Y, Yb, Er, Ho, Tm, Gd, In and Sc, and is 0.95 ≦ x ≦ 1. , 0 <y ≦ 0.5, and δ is the amount of oxygen deficiency.) A proton conductor containing a metal oxide represented by the metal oxide and a copper element contained in the metal oxide. A proton conductor in which RCu is 0.01 atomic% or more and 0.6 atomic% or less, based on the ratio of the copper element to the total amount of the element A, the element B and the element M.

Description

The present invention relates to a proton conductor and an electrochemical device using the proton conductor.
This application claims priority based on Japanese Application No. 2018-107909 filed on June 5, 2018, and incorporates all the contents described in the Japanese application.

A metal oxide having a perovskite-type structure is expected to be used in various applications because it exhibits good proton conductivity in a temperature range of 700 ° C. or lower. As a metal oxide having a perovskite-type structure, for example, BZY (BaZr _0.8 Y _0.2 O _2.9 ) is known. However, BZY has low sinterability. Therefore, in order to form BZY powder, it is usually necessary to bake at a high temperature of 1600 ° C. or higher for 20 hours or longer. At this time, Ba contained in BZY becomes BaO and easily evaporates. When BaO is evaporated, _Y 2 _{O 3} is precipitated from BZY, proton conductivity decreases.

Therefore, at the time of firing, the molded product of BZY is embedded in a mixed powder of _{BaCO 3 and BZY.} Further, a method has been proposed in which a sintering aid is added to the BZY powder, the powder is molded, and the molded product is fired (Patent Documents 1 and 2, Non-Patent Documents 1 and 2).

U.S. Patent Application Publication No. 2007/0278092 WO 2005/093130

Nikodemski, et al. “Solid-state reactive sintering mechanism for proton conducting ceramics” Solid State Ionics, 253 (2013) 201-210 Sung Min Choi, et al. “Determination of proton transference number of Ba (Zr0.84Y0.15Cu0.01) O3-δ via electrochemical concentration cell test”, J Solid State Electrochem, (2013) 17: 2833-2838

The proton conductor according to one aspect of the present invention has a perovskite-type structure and has the following formula (1):
_{A x B 1-y M y} O 3-δ (1)
(However, the element A is at least one selected from the group consisting of Ba, Ca and Sr, the element B is at least one selected from the group consisting of Ce and Zr, and the element M is Y, Yb. , Er, Ho, Tm, Gd, In and Sc, at least one selected from the group, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is the oxygen deficiency amount. ), And a proton conductor containing the copper element contained in the metal oxide.
Ratio of copper element to the total amount of the element A, the element B and the element M: R _Cu is 0.01 atomic% or more and 0.6 atomic% or less.

The electrochemical device according to another aspect of the present invention is an electrochemical device including a container having an internal space forming a reducing atmosphere and a proton conductor arranged in the internal space of the container.
The proton conductor has a perovskite-type structure and has the following formula (1):
_{A x B 1-y M y} O 3-δ (1)
(However, the element A is at least one selected from the group consisting of Ba, Ca and Sr, the element B is at least one selected from the group consisting of Ce and Zr, and the element M is Y, Yb. , Er, Ho, Tm, Gd, In and Sc, at least one selected from the group, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is the oxygen deficiency amount. ), And the copper element contained in the metal oxide.

FIG. 1 is a cross-sectional view schematically showing an example of an electrochemical device according to an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the ratio of Ni, Cu or Zn contained in the proton conductor according to the embodiment of the present invention and the proton conductivity (total conductivity) at 500 ° C. in a reducing atmosphere. is there. FIG. 3 is a diagram showing the relationship between the ratio of Ni, Cu or Zn contained in the proton conductor according to the embodiment of the present invention and the proton conductivity (total conductivity) at 600 ° C. in a reducing atmosphere. is there. FIG. 4 is a diagram showing the relationship between the ratio of Ni, Cu or Zn contained in the proton conductor according to the embodiment of the present invention and the proton conductivity (total conductivity) at 700 ° C. in a reducing atmosphere. is there. FIG. 5 is a diagram showing the relationship between the ratio of Ni, Cu or Zn contained in the proton conductor according to the embodiment of the present invention and the proton conductivity (bulk conductivity) at 300 ° C. under a reducing atmosphere. is there. FIG. 6 is a diagram showing the relationship between the ratio of Ni, Cu or Zn contained in the proton conductor according to the embodiment of the present invention and the proton conductivity (total conductivity) at 700 ° C. in an oxidizing atmosphere. is there.

[Issues to be solved by this disclosure]
As the sintering aid, for example, NiO, CuO, ZnO and the like are known. Using these sintering aids, BZY can be fired, for example, at temperatures below 1600 ° C. On the other hand, the addition of the sintering aid may reduce the proton conductivity of the obtained sintered body.

[Effect of the present disclosure]
The proton conductor according to the present disclosure has excellent proton conductivity and sinterability.

[Explanation of Embodiment]
First, embodiments of the present invention will be listed and described.
(1) The proton conductor according to one embodiment of the present invention has a perovskite-type structure and has a formula (1): A _x B _{1- y My} O _3-δ (where the element A is Ba, At least one selected from the group consisting of Ca and Sr, element B is at least one selected from the group consisting of Ce and Zr, and element M is Y, Yb, Er, Ho, Tm, Gd, At least one selected from the group consisting of In and Sc, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is an oxygen deficient amount). , A proton conductor containing the copper element contained in the metal oxide, and the ratio of the copper element to the total amount of the element A, the element B and the element M: R _Cu is 0.01 atomic%. The above is 0.6 atomic% or less. This proton conductor has excellent proton conductivity and sinterability.

(2) Further, in the proton conductor of the above-mentioned (1), the ratio of the copper element: R _Cu may be 0.15 atomic% or more and 0.4 atomic% or less. This further enhances proton conductivity.

(3) Further, in the proton conductor of the above-mentioned (1) or (2), the element A may contain Ba, the element B may contain Zr, and the element M may contain Y. Even with a metal oxide containing Zr, the sinterability is improved.

(4) The electrochemical device according to an embodiment of the present invention is an electrochemical device including a container having an internal space forming a reducing atmosphere and a proton conductor arranged in the internal space of the container. The proton conductor has a perovskite-type structure and has a formula (1): A _x B _{1- y My} O _3-δ (where the element A is from the group consisting of Ba, Ca and Sr). At least one selected, element B is at least one selected from the group consisting of Ce and Zr, and element M is from the group consisting of Y, Yb, Er, Ho, Tm, Gd, In and Sc. In the metal oxide represented by at least one selected, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is an oxygen deficiency amount), and the metal oxide. Includes copper elements and. According to this electrochemical device, the electrochemical reaction proceeds rapidly.

(5) Further, in the electrochemical device of the above-mentioned (4), the ratio of the copper element to the total amount of the element A, the element B and the element M: R _Cu is 0.01 atomic% or more, 0.6. It may be atomic% or less.

[Details of Embodiment]
Specific examples of the embodiments of the present invention will be described below with reference to the drawings as appropriate. It should be noted that the present invention is not limited to these examples, and is indicated by the appended claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[Proton conductor]
The proton conductor contains a metal oxide having a perovskite-type structure (ABO _three- phase) and a copper element contained in the metal oxide. The metal oxide is represented by the formula (1): A _x B _{1- y My} O _3-δ .

The A site contains the element A, and the B site contains the element B (which does not indicate boron). A part of the B site is replaced with the element M from the viewpoint of ensuring high proton conductivity. The ratio x of element A to the total of element B and element M is preferably 0.95 ≦ x ≦ 1 from the viewpoint of ensuring high proton conductivity and ion transport number, and 0.98 ≦ x ≦ 1. More preferably. From the viewpoint of ensuring proton conductivity, y is preferably 0 <y ≦ 0.5, and more preferably 0.1 <y ≦ 0.3.

The element A is at least one selected from the group consisting of Ba (barium), Ca (calcium) and Sr (strontium). Among them, the element A preferably contains Ba in that excellent proton conductivity can be obtained, and the ratio of Ba to the element A is preferably 50 atomic% or more, and 80 atomic% or more. Is more preferable. It is more preferable that the element A is composed only of Ba.

Element B is at least one selected from the group consisting of Ce (cerium) and Zr (zirconium). Among them, from the viewpoint of durability, the element B preferably contains Zr, and the ratio of Zr to the element B is preferably 50 atomic% or more, and more preferably 80 atomic% or more. It is more preferable that the element B is composed only of Zr. The metal oxide containing Zr has a particularly low sinterability, but according to the present embodiment, the sinterability can be improved.

The element M is selected from the group consisting of Y (yttrium), Yb (ytterbium), Er (erbium), Ho (holmium), Tm (thulium), Gd (gadolinium), In (indium) and Sc (scandium). At least one kind. The element M is a dopant, which causes oxygen defects, and the metal oxide having a perovskite-type structure exhibits proton conductivity.

In the formula (1), the oxygen deficiency amount δ can be determined according to the amount of the element M, for example, 0 ≦ δ ≦ 0.15. The ratio of each element in the metal oxide can be determined using, for example, inductively coupled plasma atomic emission spectroscopy (hereinafter referred to as ICP).

Specific examples of the metal oxide having a perovskite-type structure include yttrium-doped barium zirconate [Ba _x Zr _1-y Y _y O _3-δ (hereinafter referred to as BZY)] and yttrium-doped cerium. Barium acid [Ba _x Ce _1-y Y _y O _3-δ (BCY)], yttrium-doped barium zirconate / barium cerium mixed oxide [Ba _x Zr _1-y-z Ce _z Y _y O] _3-δ (BZCY)] and the like.

As the sintering aid, a material having a melting point lower than that of the metal oxide to be sintered and which does not easily react with the metal oxide is used. During firing, the sintering aid melts to form a liquid phase between the metal oxide powders. The liquid phase fills the gaps in the metal oxide powder and densifies, so that sintering proceeds rapidly. On the other hand, when the sintering aid is interposed between the powders of the metal oxide, the proton conductivity of the obtained sintered body tends to decrease.

However, by using a specific amount of a specific sintering aid, it is possible to improve the proton conductivity of the sintered body while improving the sinterability. The proton conductor according to this embodiment is obtained based on this finding. Sinterability is the ease of sintering, and is an index of the firing temperature and firing time required for sintering a material. For example, the lower the firing temperature and the shorter the firing time, the higher the sinterability. When the sinterability is high, the firing proceeds at a low temperature and in a short time, so that the evaporation of the element A contained in the metal oxide is suppressed. That is, the improvement of the sinterability also contributes to the improvement of the proton conductivity.

That is, in the proton conductor according to the present embodiment, a sintering aid containing Cu is added to a metal oxide having a perovskite-type structure represented by the above formula (1) (hereinafter, simply referred to as a metal oxide). It is a sintered body obtained by firing the molded product formed in the above-mentioned manner. _{The sintering aid containing Cu} is blended so that the ratio of Cu element contained in the proton conductor: R Cu is 0.01 atomic% or more and 0.6 atomic% or less. As a result, the molded product is sintered at a low temperature and in a short time, and the obtained proton conductor has excellent proton conductivity. Examples of the sintering aid containing Cu include CuO.

When, for example, NiO, CuO, and ZnO are added to the metal oxide as the sintering aid, the obtained sintered body contains Ni, Cu, and Zn, respectively. When the atomic% of these metals in the sintered body is the same, the proton conductivity of the sintered body containing Cu is the highest.

The Cu-containing proton conductor of the present embodiment (hereinafter, referred to as Cu proton conductor) can exhibit excellent proton conductivity even under conditions of, for example, about 300 ° C. In particular, when measured in a reducing atmosphere, the proton conductivity of the Cu proton conductor is high even at a low temperature. In other words, the Cu proton conductor exhibits excellent proton conductivity when used in a reducing atmosphere, regardless of the measured temperature.

The reducing atmosphere means, for example, that when a Cu proton conductor is used as an electrochemical device, the oxygen partial pressure in the reaction field is less than the equilibrium oxygen partial pressure _{PO2 of Cu 2 O at the operating temperature of the electrochemical device.} Say. For example, when the oxygen partial pressure of the reaction field at 500 ° C. is _{smaller than the equilibrium oxygen partial pressure PO2} : 2.88 × ^10-8 atm, it is said to be in a reducing atmosphere. At 600 ° C., _{when the oxygen partial pressure of the reaction field is smaller than the equilibrium oxygen partial pressure PO2} : 2.63 × ^10-6 atm, at 700 ° C., the oxygen partial pressure of the reaction field is the equilibrium oxygen partial pressure P. _O2 : When it is smaller than 9.46 × ^10-5 atm, it can be said that they are in a reducing atmosphere.

According to the Cu proton conductor, high proton conductivity is exhibited even in an oxidizing atmosphere. That is, the Cu proton conductor can exhibit excellent proton conductivity regardless of the operating atmosphere. In particular, when operated at a relatively high temperature of about 700 ° C., the proton conductivity of the Cu proton conductor is high even in an oxidizing atmosphere.

In the Cu proton conductor, the ratio of the Cu element to the total amount of the element A, the element B and the element M: R _Cu is 0.01 atomic% or more and 0.6 atomic% or less. R _Cu may be 0.1 atomic% or more, or 0.15 atomic% or more. Further, R _Cu may be 0.4 atomic% or less.

Wavelength Dispersive X-ray Analysis Using an Electron Probe Microanalyzer WDX (Wavelength Dispersive X-ray Spectroscopy), X-ray Photoelectron Spectroscopy (XPS (X-ray Photoelectron Spectroscopy) or ESCA (Electron Spectro) , The ratio of element B, element M and Cu can be obtained, and R _{Cu in} the sample can be obtained.

[Manufacturing method of proton conductor]
The Cu proton conductor can be obtained, for example, by molding a raw material containing a metal oxide powder and a CuO powder into a desired shape and then firing the material. The CuO powder is added, for example, in an amount of 0.1% by mass to 5% by mass based on the total amount of the metal oxide and CuO.

The raw material preferably contains a binder from the viewpoint of moldability. As the binder, known materials used for producing ceramic materials, for example, cellulose derivatives such as ethyl cellulose (cellulose ether and the like), vinyl acetate-based resins (including saponified products of vinyl acetate-based resins such as provinyl alcohol), and the like. Polymer binders such as acrylic resin; waxes such as paraffin wax and the like can be mentioned. The amount of the binder is, for example, 1 to 20 parts by mass, particularly 1.5 to 15 parts by mass with respect to 100 parts by mass of the metal oxide.

If necessary, the raw material may contain a dispersion medium such as water, an organic solvent (for example, a hydrocarbon such as toluene; an alcohol such as ethanol or isopropanol; or a dispersion medium such as butyl carbitol acetate). The raw material may contain various additives such as a surfactant and a glutinous agent (polycarboxylic acid and the like), if necessary.

The molding method is not particularly limited, and may be appropriately selected depending on the desired shape. For example, the flat plate-shaped proton conductor can be molded by using an existing method such as press molding, tape molding, screen printing, spray coating, spin coating, and dip coating.

Firing is performed by heating the obtained molded product in an oxygen-containing atmosphere. The firing temperature of the molded product to which CuO is added may be, for example, less than 1600 ° C. and may be 1500 ° C. or lower. The firing time may be, for example, 20 hours or less, 15 hours or less, and 10 hours or less. The oxygen content in the firing atmosphere is not particularly limited. The calcination may be performed in an air atmosphere (oxygen content: about 20% by volume) or in pure oxygen (oxygen content: 100% by volume), for example. Baking can be carried out under normal pressure or pressure.

[Electrochemical device]
By the way, the Cu proton conductor exhibits particularly excellent proton conductivity when used under specific conditions regardless _{of the ratio of Cu element: R Cu.} For example, the proton conductivity in the reducing atmosphere of a Cu proton conductor is compared with the proton conductivity in the reducing atmosphere of a proton conductor obtained by sintering only a metal oxide without adding a sintering aid. Not inferior. The electrochemical device according to this embodiment is based on this finding.

That is, the electrochemical device according to the present embodiment includes a container having an internal space for forming a reducing atmosphere, and a Cu proton conductor arranged in the internal space of the container. An electrochemical device is a device that transfers electrons between substances and causes a chemical reaction by transferring the electrons.

Specific examples of the electrochemical device include a hydrogen separator, a hydrogen pump, a gas decomposition device, and the like.

The container is a reaction field where an electrochemical reaction occurs, and a reducing atmosphere is formed in the internal space of the container. When the internal space is a reducing atmosphere, although the details are unknown, the proton conductivity of the Cu proton conductor arranged in the internal space is improved, and the electrochemical reaction proceeds rapidly.

The operating conditions of the electrochemical device may be 300 ° C. or higher, 500 ° C. or higher, 600 ° C. or higher, or 700 ° C. or higher. The proton conductivity of a proton conductor generally improves as the operating temperature increases. The Cu proton conductor exhibits excellent proton conductivity in a reducing atmosphere even at a relatively low temperature of about 300 ° C.

FIG. 1 is a cross-sectional view schematically showing an example of an electrochemical device according to the present embodiment.
The electrochemical device 10 includes a container 4 and a Cu proton conductor 1 arranged in the internal space of the container 4. A reducing atmosphere is formed in the internal space.

The Cu proton conductor 1 is sandwiched between, for example, a pair of electrodes (anode 2 and cathode 3). The internal space of the container 4 is separated by the Cu proton conductor 1 into a space S1 on the anode 2 side and a space S2 on the cathode 3 side. The gas containing a hydrogen atom (first gas G1) is supplied to the space S1 from the first supply port 4a. Protons are generated from the first gas G1 by an electrochemical reaction to generate a second gas G2 (for example, hydrogen gas) in the space S2. The second gas G2 is discharged from the container 4 through the discharge port 4b. The container 4 includes a second supply port 4c that supplies the third gas G3 to the space S2, if necessary.

When the first gas G1 is brought into contact with the anode 2 and a voltage is applied between the electrodes, a reaction that releases protons and electrons occurs at the anode 2. The released protons move from the first main surface of the Cu proton conductor 1 in contact with the anode 2 to the second main surface of the Cu proton conductor 1 in contact with the cathode 3. The proton receives an electron again on the second main surface side and is discharged from the cathode 3 as a hydrogen gas. Alternatively, the protons can react with the third gas G3 supplied to the cathode 3 to produce new compounds. Further, the hydrogen gas discharged from the cathode 3 can react with the third gas G3 supplied to the space S2 to generate a new compound. That is, the Cu proton conductor 1 can function as a membrane reactor.

As shown in FIG. 1, when the internal space of the container is separated by the Cu proton conductor, at least the space on the anode side may be a reducing atmosphere.

The case where the electrochemical device is a hydrogen separator will be described as an example.
The hydrogen separator separates and takes out hydrogen gas from a mixed gas containing hydrogen gas.
For example, a voltage is applied between the anode 2 and the cathode 3, and the first gas G1 containing hydrogen gas is supplied to the space S1. The first gas G1 comes into contact with the anode 2, and the hydrogen gas contained in the first gas G1 is decomposed at the anode 2. This produces protons and electrons. The protons that have moved in the Cu proton conductor 1 receive electrons from the cathode 3 and are isolated as pure hydrogen gas.

(anode)
The anode has, for example, a proton-conducting porous structure. The material of the anode is not particularly limited. The anode may be composed of, for example, the above-mentioned sintered body of the metal oxide, or may be a platinum electrode.

(Cathode)
The cathode has, for example, an ionic conductive porous structure. The material of the cathode is not particularly limited, and may be appropriately selected depending on the intended use. The cathode may be, for example, an electrode made of platinum, an ionic conductive oxide, or the like.

Hereinafter, the present invention will be described in more detail based on Examples, but the following Examples do not limit the present invention.

[Examples 1 to 4]
(1) Preparation of metal oxide (BaZr _0.8 Y _0.2 O _2.9 ) Barium carbonate, zirconium oxide, and yttrium oxide are mixed with Ba ratio x of 1 and Y ratio y of 0.2. Each was placed in a ball mill and mixed for 24 hours at a molar ratio such that, to obtain a mixture. The obtained mixture was calcined at 1000 ° C. for 10 hours. The tentatively calcined mixture was treated with a ball mill for 10 hours, uniaxially molded, and then calcined at 1300 ° C. for 10 hours in an air atmosphere. The calcined sample was pulverized in a mortar and then treated with a ball mill for 10 hours to obtain a metal oxide.

(2) Preparation of sintered body and sample electrode CuO was mixed with the obtained metal oxide in an amount of 0.2% by mass, 0.5% by mass, 1% by mass, and 2% by mass, respectively, and uniaxially formed into pellets. After that, it was molded by a press molding method. The molded product was sintered by heat treatment at 1500 ° C. for 10 hours in an oxygen atmosphere to prepare sintered bodies A1 to A4 containing a metal oxide and Cu. The ratio of Cu element contained in each of the sintered bodies A1 to A4: R _Cu was about 0.16 at%, about 0.33 at%, about 0.53 at%, and about 0.81 at%, respectively. “At%” means atomic%.

[Comparative Example 1]
In "Preparation of sintered body and sample electrode (2)", CuO was not added, and the molded product obtained by press molding was mixed powder of BZY and barium carbonate [BZY: BaCO ₃ = 100]. Sintered body a in the same manner as in Examples 1 to 4 except that it was embedded in 1 (mass ratio)] and sintered by heat treatment at 1600 ° C. for 24 hours in an oxygen atmosphere. Was produced.

[Comparative Examples 2 to 5]
Sintered bodies b1 to b4 were prepared in the same manner as in Examples 1 to 4 except that NiO was added instead of CuO in "Preparation of sintered body and sample electrode (2)". The proportions of Ni contained in each of the sintered bodies b1 to b4 were about 0.39 at%, about 0.68 at%, about 1.25 at%, and about 2.13 at%, respectively.

[Comparative Examples 6 to 9]
Sintered bodies c1 to c4 were prepared in the same manner as in Examples 1 to 4 except that ZnO was added instead of CuO in "Preparation of sintered body and sample electrode (2)". The proportions of Zn contained in each of the sintered bodies c1 to c4 were about 0.24 at%, about 0.52 at%, about 0.69 at%, and about 0.82 at%, respectively.

[Evaluation of proton conductivity 1]
Pt electrodes were formed on both sides of the sintered bodies obtained in Examples 1 to 4, Comparative Example 1, Comparative Examples 2 to 5 and Comparative Examples 6 to 9 by a sputtering method to prepare sample electrodes. The sample electrode was treated under the following conditions.

(A) Treatment in an oxidizing atmosphere (first time)
The sample electrode after Pt sputtering was attached to a holder for measurement, placed in an electric furnace, and heated to 500 ° C. Treatment was performed for 18 hours while supplying humidified oxygen so that the oxygen partial pressure was 0.95 atm (9.5 × 10 ⁴ Pa) and the water vapor partial pressure was 0.05 atm (0.5 × 10 ^{4 Pa).} ..

(B) Treatment in a reducing atmosphere After the treatment (A), the hydrogen partial pressure becomes 0.95 atm (9.5 × 10 ⁴ Pa) and the water vapor partial pressure becomes 0.05 atm (0.5 × 10 ⁴ Pa). As described above, the treatment was carried out at 500 ° C. for 10 hours while supplying humidified hydrogen.

(C) Treatment in an oxidizing atmosphere (second time)
After the treatment (B), the oxygen re-humidified so that the oxygen partial pressure becomes 0.95 atm (9.5 × 10 ⁴ Pa) and the water vapor partial pressure becomes 0.05 atm (0.5 × 10 ^{4 Pa).} While feeding, it was treated at 500 ° C. for 10 hours.

After "treatment in a reducing atmosphere (B)", the total conductivity was determined by measuring the AC impedance. The results are shown in FIG. Solartron 1260 (manufactured by Solartron Analytical) was used for the AC impedance measurement.

[Evaluation of proton conductivity 2]
The treatment temperature was set to 600 ° C. in "treatment in an oxidizing atmosphere (first time) (A)", "treatment in a reducing atmosphere (B)" and "treatment in an oxidizing atmosphere (second time) (C)". Except for the above, each sample electrode was treated in the same manner as in Evaluation 1.
After "treatment in a reducing atmosphere (B)", the total conductivity was determined by measuring the AC impedance. The results are shown in FIG.

[Evaluation of proton conductivity 3]
The treatment temperature was set to 700 ° C. in "treatment in an oxidizing atmosphere (first time) (A)", "treatment in a reducing atmosphere (B)" and "treatment in an oxidizing atmosphere (second time) (C)". Except for the above, each sample electrode was treated in the same manner as in Evaluation 1.
After "treatment in a reducing atmosphere (B)", the total conductivity was determined by measuring the AC impedance. The results are shown in FIG.

[Evaluation of proton conductivity 4]
The treatment temperature was set to 300 ° C. in "treatment in an oxidizing atmosphere (first time) (A)", "treatment in a reducing atmosphere (B)" and "treatment in an oxidizing atmosphere (second time) (C)". Except for the above, each sample electrode was treated in the same manner as in Evaluation 1.
After "treatment in a reducing atmosphere (B)", the bulk conductivity was determined by measuring the AC impedance. The results are shown in FIG.

[Evaluation of proton conductivity 5]
The treatment temperature was set to 700 ° C. in "treatment in an oxidizing atmosphere (first time) (A)", "treatment in a reducing atmosphere (B)" and "treatment in an oxidizing atmosphere (second time) (C)". Except for the above, each sample electrode was treated in the same manner as in Evaluation 1.
After "treatment in an oxidizing atmosphere (second time) (C)", the total conductivity was determined by AC impedance measurement. The results are shown in FIG.

The proton conductor according to the embodiment of the present invention is suitable for various electrochemical devices because it has excellent sinterability and proton conductivity.

10: Electrochemical device 1: Cu proton conductor 2: Anode 3: Cathode 4: Container 4a: First supply port 4b: Discharge port 4c: Second supply port

Claims (5)

It has a perovskite-type structure and has the following formula (1):
_{A x B 1-y M y} O 3-δ (1)
(However, the element A is at least one selected from the group consisting of Ba, Ca and Sr, the element B is at least one selected from the group consisting of Ce and Zr, and the element M is Y, Yb. , Er, Ho, Tm, Gd, In and Sc, at least one selected from the group, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, where δ is the oxygen deficiency amount. )
With the metal oxide represented by
A proton conductor containing a copper element contained in the metal oxide.
Ratio of copper element to the total amount of the element A, the element B and the element M: R _Cu is a proton conductor having 0.01 atomic% or more and 0.6 atomic% or less. The proton conductor according to claim 1, wherein the ratio of the copper element: RCu is 0.15 atomic% or more and 0.4 atomic% or less. The element A contains Ba and contains
The element B contains Zr and contains
The proton conductor according to claim 1 or 2, wherein the element M contains Y. A container with an internal space that forms a reducing atmosphere,
An electrochemical device comprising a proton conductor arranged in the interior space of the container.
The proton conductor is
It has a perovskite-type structure and has the following formula (1):
_{A x B 1-y M y} O 3-δ (1)
(However, the element A is at least one selected from the group consisting of Ba, Ca and Sr, the element B is at least one selected from the group consisting of Ce and Zr, and the element M is Y, Yb. , Er, Ho, Tm, Gd, In and Sc, at least one selected from the group, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, where δ is the oxygen deficiency amount. )
With the metal oxide represented by
An electrochemical device containing a copper element contained in the metal oxide. The electrochemical device according to claim 4, wherein the ratio of the copper element to the total amount of the element A, the element B and the element M: R _Cu is 0.01 atomic% or more and 0.6 atomic% or less.

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