WO2019235025A1 - Proton conductor and electrochemical device using same - Google Patents

Abstract

A proton conductor which has a perovskite structure, and which contains a metal oxide represented by formula (1) AxB1-yMyO3-δ (wherein element A represents at least one element that is selected from the group consisting of Ba, Ca and Sr; element B represents at least one element that is selected from the group consisting of Ce and Zr; element M represents at least one element that is selected from the group consisting of Y, Yb, Er, Ho, Tm, Gd, In and Sc; x and y satisfy 0.95 ≤ x ≤ 1 and 0 < y ≤ 0.5; and δ represents the amount of oxygen deficiency) and elemental copper contained in the metal oxide. With respect to this proton conductor, the ratio of the elemental copper RCu to the total amount of the element A, the element B and the element M is from 0.01% by atom to 0.6% by atom (inclusive).

Description

Proton conductor and electrochemical device using the same

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

A metal oxide having a perovskite 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 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 fire at a high temperature of 1600 ° C. or more for 20 hours or more. At this time, Ba contained in BZY is easily evaporated as BaO. When BaO evaporates, Y ₂ O ₃ precipitates from BZY, and proton conductivity decreases.

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

US Patent Application Publication No. 2007/0278092 International Publication No. 2005/093130 Specification

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 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, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is the amount of oxygen deficiency. A proton conductor comprising: a metal oxide represented by :) and a copper element contained in the metal oxide,
Ratio of copper element to total amount of element A, element B and element M: R _Cu is 0.01 atomic% or more and 0.6 atomic% or less.

An electrochemical device according to another aspect of the present invention is an electrochemical device comprising: a container having an internal space that forms a reducing atmosphere; and a proton conductor disposed in the internal space of the container,
The proton conductor has a perovskite 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, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is the amount of oxygen deficiency. And a 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 proportion of Ni, Cu or Zn contained in the proton conductor according to one 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 one embodiment of the present invention and proton conductivity (total conductivity) at 600 ° C. in a reducing atmosphere. is there. FIG. 4 is a diagram showing the relationship between the proportion of Ni, Cu or Zn contained in the proton conductor according to one embodiment of the present invention and proton conductivity (total conductivity) at 700 ° C. in a reducing atmosphere. is there. FIG. 5 is a diagram showing the relationship between the proportion of Ni, Cu or Zn contained in the proton conductor according to one embodiment of the present invention and proton conductivity (bulk conductivity) at 300 ° C. in a reducing atmosphere. is there. FIG. 6 is a graph showing the relationship between the ratio of Ni, Cu or Zn contained in the proton conductor according to one embodiment of the present invention and proton conductivity (total conductivity) at 700 ° C. in an oxidizing atmosphere. is there.

[Problems to be solved by the present disclosure]
As the sintering aid, for example, NiO, CuO, ZnO and the like are known. When these sintering aids are used, BZY can be fired at a temperature of less than 1600 ° C., for example. On the other hand, the addition of a sintering aid may decrease the proton conductivity of the obtained sintered body.

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

[Description of Embodiment]
First, embodiments of the present invention will be listed and described.
(1) A proton conductor according to an embodiment of the present invention has a perovskite structure, and has the formula (1): A _x B _1-y M _y O _3-δ (wherein element A is Ba, At least one selected from the group consisting of 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, A metal oxide represented by at least one selected from the group consisting of In and Sc, 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is the amount of oxygen deficiency) And a copper conductor contained in the metal oxide, 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% As mentioned above, it is 0.6 atomic% or less. This proton conductor has excellent proton conductivity and sinterability.

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

(3) In the proton conductor of (1) or (2) described above, the element A may include Ba, the element B may include Zr, and the element M may include Y. Even if it is a metal oxide containing Zr, the sinterability is improved.

(4) An electrochemical device according to an embodiment of the present invention is an electrochemical device comprising: a container having an internal space forming a reducing atmosphere; and a proton conductor disposed in the internal space of the container. The proton conductor has a perovskite structure and has the formula (1): A _x B _1-y M _y O _3-δ (wherein the element A is selected 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. At least one selected, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is an oxygen deficiency amount) in the metal oxide Containing copper element According to this electrochemical device, the electrochemical reaction proceeds rapidly.

(5) Moreover, 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 at most atomic%.

[Details of the embodiment]
Specific examples of embodiments of the present invention will be described below with reference to the drawings as appropriate. In addition, this invention is not limited to these illustrations, is shown by the attached claim, and it is intended that all the changes within the meaning and range equivalent to a claim are included.

[Proton conductor]
The proton conductor includes a metal oxide having a perovskite structure (ABO ₃ phase) and a copper element contained in the metal oxide. The metal oxide is represented by the formula (1): A _x B _1-y M _y O _3-δ .

The element A enters the A site and the element B (not indicating boron) enters the B site. A part of the B site is substituted with the element M from the viewpoint of ensuring high proton conductivity. The ratio x of the element A to the total of the elements B and 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.

Element A is at least one selected from the group consisting of Ba (barium), Ca (calcium), and Sr (strontium). Especially, it is preferable that the element A contains Ba by the point from which the outstanding proton conductivity is obtained, and it is preferable that the ratio of Ba to the element A is 50 atomic% or more, and is 80 atomic% or more. Is more preferable. More preferably, 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 these, from the viewpoint of durability, the element B preferably contains Zr, and the proportion of Zr in the element B is preferably 50 atomic% or more, and more preferably 80 atomic% or more. More preferably, the element B is composed only of Zr. Although the metal oxide containing Zr has particularly low sinterability, according to this 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 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, a high-frequency inductively coupled plasma emission spectroscopy (hereinafter referred to as ICP).

Specific examples of metal oxides having a perovskite structure include barium zirconate doped with yttrium [Ba _x Zr _1-y Y _y O _3-δ (hereinafter referred to as BZY)], cerium doped with yttrium. Barium oxide [Ba _x Ce _1-y Y _y O _3-δ (BCY)], mixed oxide of barium zirconate / barium cerate doped with yttrium [Ba _x Zr _1-yz 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 hardly reacting with the metal oxide is used. During firing, the sintering aid melts to form a liquid phase between the metal oxide powders. This liquid phase fills the gaps in the metal oxide powder and densifies, whereby the sintering proceeds quickly. On the other hand, when the sintering aid is interposed between the metal oxide powders, the proton conductivity of the obtained sintered body tends to decrease.

However, by using a specific amount of a specific sintering aid, the proton conductivity of the sintered body can be improved while improving the sinterability. The proton conductor according to the present embodiment is obtained based on this finding. Sinterability is the ease of sintering, and the firing temperature and firing time necessary to sinter the material are indicators thereof. For example, the lower the firing temperature and the shorter the firing time, the higher the sinterability. When the sinterability is high, firing proceeds at a low temperature in a short time, and thus evaporation of the element A contained in the metal oxide is suppressed. That is, the improvement of sinterability also contributes to the improvement of 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 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 molded in this 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 for a short time, and the obtained proton conductor has excellent proton conductivity. An example of the sintering aid containing Cu is CuO.

For example, when adding NiO, CuO, and ZnO to the metal oxide as sintering aids, the resulting sintered bodies contain Ni, Cu, and Zn, respectively. When the atomic percent of these metals in the sintered body is the same, the proton conductivity of the sintered body containing Cu is the highest.

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

For example, when a Cu proton conductor is used as an electrochemical device, the reducing atmosphere is a case where the oxygen partial pressure in the reaction field is less than the equilibrium oxygen partial pressure P _O2 of Cu ₂ O at the operating temperature of the electrochemical device. Say. For example, when the oxygen partial pressure in the reaction field at 500 ° C. is smaller than the equilibrium oxygen partial pressure P _O2 : 2.88 × 10 ⁻⁸ atm, the reducing atmosphere is assumed. At 600 ° C., when the oxygen partial pressure in the reaction field is smaller than the equilibrium oxygen partial pressure P _O2 : 2.63 × 10 ⁻⁶ atm, at 700 ° C., the oxygen partial pressure in the reaction field is equal to the equilibrium oxygen partial pressure P _{When O2} is less than 9.46 × 10 ⁻⁵ atm, it can be said that each is in a reducing atmosphere.

According to Cu proton conductor, high proton conductivity is exhibited even in an oxidizing atmosphere. That is, regardless of the operating atmosphere, the Cu proton conductor can exhibit excellent proton conductivity. 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 Cu element to the total amount of element A, element B and 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 Spectroscopy Spectroscopy) The ratio of element B, element M and Cu can be determined, and R _{Cu in} the sample can be determined.

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

The raw material preferably contains a binder from the viewpoint of moldability. As the binder, known materials used for the production of ceramic materials, for example, cellulose derivatives such as ethyl cellulose (cellulose ether and the like), vinyl acetate resins (including saponified vinyl acetate resins such as provinyl alcohol), Examples thereof include polymer binders such as acrylic resins; waxes such as paraffin wax. 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.

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

The forming method is not particularly limited, and may be appropriately selected according to a desired shape. For example, the flat proton conductor can be formed using existing methods such as press molding, tape molding, screen printing, spray coating, spin coating, dip coating, and the like.

Calcination 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. or 1500 ° C. or less. 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. Firing may be performed, for example, in an air atmosphere (oxygen content: about 20% by volume) or in pure oxygen (oxygen content: 100% by volume). Firing can be performed under normal pressure or under pressure.

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

That is, the electrochemical device according to this embodiment includes a container having an internal space that forms a reducing atmosphere, and a Cu proton conductor disposed in the internal space of the container. An electrochemical device is an apparatus that exchanges electrons between substances and causes a chemical reaction by the exchange of electrons.

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

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

The operating condition 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 the 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 this embodiment.
The electrochemical device 10 includes a container 4 and a Cu proton conductor 1 disposed in the internal space of the container 4. A reducing atmosphere is formed in the internal space.

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. A gas containing hydrogen atoms (first gas G1) is supplied from the first supply port 4a to the space S1. Protons are generated from the first gas G1 by an electrochemical reaction, and a second gas G2 (for example, hydrogen gas) is generated 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 as necessary.

When the first gas G1 is brought into contact with the anode 2 and a voltage is applied between the electrodes, the anode 2 undergoes a reaction that releases protons and electrons. 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. Protons receive electrons again on the second main surface side and are discharged from the cathode 3 as hydrogen gas. Alternatively, protons can react with the third gas G3 supplied to the cathode 3 to generate a new compound. 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.

A case where the electrochemical device is a hydrogen separator will be described as an example.
The hydrogen separator separates and extracts hydrogen gas from a mixed gas containing hydrogen gas.
For example, a voltage is applied between the anode 2 and the cathode 3 and a 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. Protons that have moved through 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 conductive porous structure. The material of the anode is not particularly limited. The anode may be composed of, for example, a sintered body of the above metal oxide, or may be a platinum electrode.

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

Hereinafter, the present invention will be described more specifically based on examples. However, the following examples do not limit the present invention.

[Examples 1 to 4]
(1) Production of Metal Oxide (BaZr _0.8 Y _0.2 O _2.9 ) Barium carbonate, zirconium oxide, and yttrium oxide, Ba ratio x is 1, Y ratio y is 0.2. In such a molar ratio, each was placed in a ball mill and mixed for 24 hours to obtain a mixture. The obtained mixture was calcined at 1000 ° C. for 10 hours. The pre-fired mixture was treated with a ball mill for 10 hours and uniaxially molded, and then fired at 1300 ° C. for 10 hours in an air atmosphere. The fired sample was pulverized with 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 The obtained metal oxide was mixed with 0.2% by mass, 0.5% by mass, 1% by mass, and 2% by mass of CuO, respectively, and uniaxially formed into pellets. After being obtained, 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 produce sintered bodies A1 to A4 containing 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. : 1 (mass ratio)], and sintered in the same manner as in Examples 1 to 4 except that it was sintered by heat treatment at 1600 ° C. for 24 hours in an oxygen atmosphere. Was made.

[Comparative Examples 2 to 5]
Sintered bodies b1 to b4 were manufactured 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 ratio of Ni contained in each of the sintered bodies b1 to b4 was 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 manufactured 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 ratio of Zn contained in each of the sintered bodies c1 to c4 was 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 surfaces 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 sputtering to prepare sample electrodes. The sample electrode was processed under the following conditions.

(A) Treatment in an oxidizing atmosphere (first time)
The sample electrode after Pt sputtering was attached to a measurement holder, placed in an electric furnace, and heated to 500 ° C. It was treated 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 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). Thus, it processed at 500 degreeC for 10 hours, supplying humidified hydrogen.

(C) Treatment in an oxidizing atmosphere (second time)
After the treatment (B), oxygen which has been humidified again is adjusted so that the oxygen partial pressure is 0.95 atm (9.5 × 10 ⁴ Pa) and the water vapor partial pressure is 0.05 atm (0.5 × 10 ⁴ Pa). While supplying, it was treated at 500 ° C. for 10 hours.

After the “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 AC impedance measurement.

[Evaluation of proton conductivity 2]
The processing temperature was set to 600 ° C. in “treatment in oxidizing atmosphere (first time) (A)”, “treatment in reducing atmosphere (B)” and “treatment in 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 reducing atmosphere (B)”, the total conductivity was determined by AC impedance measurement. The results are shown in FIG.

[Evaluation of proton conductivity 3]
The treatment temperature was set to 700 ° C. in “treatment in oxidizing atmosphere (first time) (A)”, “treatment in reducing atmosphere (B)” and “treatment in 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 reducing atmosphere (B)”, the total conductivity was determined by AC impedance measurement. The results are shown in FIG.

[Evaluation of proton conductivity 4]
The treatment temperature was set to 300 ° C. in “treatment in oxidizing atmosphere (first time) (A)”, “treatment in reducing atmosphere (B)” and “treatment in 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 reducing atmosphere (B)”, bulk conductivity was determined by AC impedance measurement. The results are shown in FIG.

[Evaluation of proton conductivity 5]
The processing temperature was set to 700 ° C. in “treatment in oxidizing atmosphere (first time) (A)”, “treatment in reducing atmosphere (B)” and “treatment in 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.

Since the proton conductor according to the embodiment of the present invention is excellent in sinterability and proton conductivity, it is suitable for various electrochemical devices.

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 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, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is the amount of oxygen deficiency. )
A metal oxide represented by
A proton conductor containing copper element contained in the metal oxide,
Ratio of copper element with respect to total amount of element A, element B, and element M: R _Cu is a proton conductor that is 0.01 atomic% or more and 0.6 atomic% or less. The ratio of the said copper element: The proton conductor of Claim 1 whose RCu is 0.15 atomic% or more and 0.4 atomic% or less. The element A includes Ba;
The element B contains Zr;
The proton conductor according to claim 1 or 2, wherein the element M includes Y. A container having an internal space forming a reducing atmosphere;
An electrochemical device comprising: a proton conductor disposed in the internal space of the container;
The proton conductor is
It has a perovskite 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, satisfying 0.95 ≦ x ≦ 1, 0 <y ≦ 0.5, and δ is the amount of oxygen deficiency. )
A metal oxide represented by
An electrochemical device comprising a copper element contained in the metal oxide. The ratio of the copper element with respect to the total amount of the said element A, the said element B, and the said element M: _RCu is an electrochemical device of Claim 4 which is 0.01 atomic% or more and 0.6 atomic% or less.

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