JP4304666B2 - Proton conductive material, proton conductive structure, fuel cell, and method for producing proton conductive structure - Google Patents

Description

  The present invention relates to a hydrogen battery, a galvanic cell humidity sensor, a high-performance proton (hydrogen ion) conductive material that can be used for a fuel cell, a proton conductive structure, a fuel cell, and a method for producing a proton conductive structure. It is about.

  The proton conductive membrane can be used as a hydrogen separation membrane because protons, not electrons, propagate through the solid electrolyte membrane. The solid electrolyte membrane described in Patent Document 1 is used in a method for separating hydrogen from a hydrogen-containing gas. These solid electrolytes are mainly composed of oxides such as strontium, cerium, and scandium, and have a perovskite crystal structure.

A material having a perovskite crystal structure is generally a kind of ceramic having a chemical composition of ABO ₃ . However, A and B are metal elements, and O is an oxygen atom. Since these solid electrolytes are oxide-based ceramics, they are produced in an oxidizing atmosphere and at a high firing temperature. The example of Patent Document 1 is fired at a high temperature of 1430 ° C., and the atmosphere seems to be an oxidizing atmosphere.

  Patent Document 2 does not specify the crystal structure of the solid electrolyte. However, since the oxide having the same composition as Patent Document 1 is fired at 500 to 1500 ° C., preferably 600 to 1450 ° C., it seems to be a perovskite crystal structure. Such a proton conductive solid electrolyte is used as a galvanic cell type humidity sensor.

Japanese Patent Publication No.62-47054 JP-A-58-50458

  Patent Documents 1 and 2 describe that a solid electrolyte having a perovskite-type crystal structure is prepared, and then a base material or an electrode that is a hydrogen gas permeable film is attached. However, there is no description about the specific method of attachment.

  Patent Documents 1 and 2 describe that a proton conductive material having a perovskite crystal structure is produced in a high-temperature oxygen atmosphere. However, since the hydrogen-permeable base material used in the present invention is oxidized at a high temperature and cannot be used, the base material cannot be directly bonded to a proton conductive material having a perovskite crystal structure during the firing process. .

  Under the circumstances as described above, the present invention intends to directly produce a proton conductive material on a metal substrate such as an electrode. A conventional perovskite structure solid electrolyte having proton conductivity is fired at a high temperature of 500 ° C. or higher and in an oxidizing atmosphere. In the present invention, the temperature is lowered and an amorphous solid electrolyte is used. By doing so, an attempt is made to produce a material in which the proton conductive material and the substrate are directly joined without impairing the hydrogen permeability of the substrate.

  The first of the present invention, at least one first element selected from the group consisting of Mg, Ca, Sr and Ba, at least one second element selected from the group consisting of Ce, Zr, Ti and Hf, oxygen A material having an amorphous structure having a composition comprising: the first peak position of the diffraction pattern of the material is between 25 ° and 35 ° in the X-ray diffraction measurement using CuKα rays, and the above-mentioned peak This relates to a proton conductive material having a half width of 2 ° or more.

  A major feature of the present invention is that a proton conductive solid electrolyte having an amorphous state, not a perovskite structure, has been found. In conventional proton conductive materials, it has been considered that protons pass between crystal lattices of a perovskite structure. On the other hand, the amorphous material does not have a regular crystal lattice like perovskite and has not been confirmed to have proton conductivity.

  Since the amorphous proton conductive material (amorphous solid electrolyte) of the present invention is formed in an oxygen atmosphere at a low temperature of room temperature to about 500 ° C. or lower, Pd, Pd alloy, V, It can be directly laminated on V alloy. Since the film forming temperature is low, the amorphous solid electrolyte can be laminated without oxidizing the base material. In addition, since it is amorphous, the surface roughness of the film surface is small, and a dense film quality without pinholes can be obtained.

  Another feature of being amorphous is that it contains a first element and a second element and exhibits high proton conductivity. A conventional proton conductive material having a perovskite crystal structure includes a Group IIIa element such as scandium, yttrium, yttrium, or neodymium in the first element and the second element. When the number of elements used is small, the production is simplified, which is preferable.

  The meaning of amorphous in the present invention is that the first peak of the diffraction pattern in X-ray diffraction is broad, that is, broad, and the highest peak position of the diffraction pattern is 2θ at 25 ° and 35 °. It is in between. As will be described later, the width of the peak at half the height between the line connecting the baseline of the peak and the highest height of the peak is referred to as the half-value width, and the amorphous structure referred to in the present invention is 2 ° or more. Is to have. In other words, the peak spread is determined by the half width.

  The second of the present invention is an invention in which a part of the second element of the first invention is replaced with at least one selected from the group consisting of Sc, Y and lanthanoids. The constituent elements are the same as those of the perovskite type having a conventional crystal structure. However, since an amorphous structure can be directly laminated on a hydrogen permeable electrode such as Pd, even a thin proton conductive film quality can be put into practical use.

  The proton conductive material of the present invention may have a sharp second peak generated from a perovskite structure having a peak position between 28 ° and 32 ° in addition to the aforementioned broad first peak in X-ray diffraction measurement. Good. Those having an amorphous structure and those having a perovskite crystal structure can coexist.

  In the first invention, it is preferable that the composition of the proton conductive material is 8-30 atomic% for the first element, 8-30 atomic% for the second element, and the balance is oxygen. The characteristic of being amorphous is that practical performance can be obtained even if the first element and the second element are not in an atomic ratio of 1: 1.

  In the second invention, the composition of the proton conductive material is 8-30 atomic% for the first element and 8-30 atomic% for the second element, provided that a part of the second element is composed of the third element with respect to the whole. It is preferable that 0.1 to 5 atomic% is substituted, and the balance is oxygen. It has been found that by being amorphous, practical performance can be obtained even if the first element and the second element are not 1: 1.

  The thickness of the proton conductive material is desirably 0.05 μm or more and 5 μm or less. If the thickness is less than 0.05 μm, hydrogen gas may pass through as it is without becoming ions. On the other hand, if it exceeds 5 μm, the proton permeation performance deteriorates, and a large output cannot be obtained when used in a fuel cell. Since the proton conductive material of the present invention is thinner than the sintered body, a large number of proton conductive membranes can be accommodated in a narrow volume and a compact and high output fuel cell can be provided.

  The proton conductive structure of the present invention is obtained by forming the proton conductive material described above on a substrate. With reference to FIG. 1, the proton conductive structure according to the present invention includes a substrate 1 made of a hydrogen permeable metal serving as a hydrogen electrode on one side of a proton conductive material 3.

  As the substrate used in the present invention, a metal film having hydrogen permeability is desirable. Specifically, Pd alloy base materials such as Pd, Pd-Ag, and Pd-Cu, V plates coated on both sides of Pd, V alloys such as V-Ni or laminated plates, Ta alloy plates, Nb alloy plates, etc. An alloy plate is desirable. Here, when Pd is coated on the metal plate as described above, the thickness is desirably 0.05 μm to 0.3 μm, and more preferably 0.1 μm to 0.2 μm. The total thickness of the proton conductive material and the base material is preferably 10 μm to 0.5 mm, particularly preferably 25 μm to 200 μm. At this time, the base material can reinforce the proton conductive material.

  The fuel cell of the present invention uses the proton conductive material described above. A conceptual cross-sectional view is shown in FIG. A proton conductive material 3 is disposed between the substrate 1 and the oxygen electrode 2 to form a partition wall. A fuel cell 4 is formed by flowing a gas containing hydrogen on the base material 1 side of the partition wall and a gas containing oxygen on the oxygen electrode 2 side on the opposite side.

  When hydrogen permeates the base material 1 and reaches the proton conductive material 3, electrons of hydrogen atoms are taken to become protons. Protons pass through the proton conductive material 3 and reach the oxygen electrode 2. Electrons emitted on the substrate side reach the oxygen electrode 2 through a circuit in which the load 5 and ammeter 6 are connected in series and the voltmeter 7 is connected in parallel. Flows to the side. On the oxygen electrode side, protons, electrons, and oxygen are combined and discharged as water outside the battery 4.

  As the oxygen electrode, Pd, Pt, Ni, and Ru are alloys containing them, and a thin film electrode having a thickness of 0.01 to 10 μm or a porous electrode made of a noble metal or an oxide is used. As a production method, a thin film by a vapor phase method, a film formation by a wet method, and a baking method are preferable.

  The present invention provides a proton conductive structure in which the above proton conductive material is vapor-phase-deposited on a substrate in a reduced pressure oxygen atmosphere having a film formation temperature of room temperature to 500 ° C. and an atmosphere of 0.13 kPa (1 Torr) or less. A manufacturing method is provided. Among them, the vapor deposition of the proton conductive film is preferably a laser ablation method, a sputtering method, an ion plating method or the like. In the case of sputtering, the RF magnetron sputtering method is preferable. The film forming temperature is preferably 500 ° C. or lower and room temperature or higher, but more preferably 200 ° C. or higher and 400 ° C. or lower.

  In the case of a sputtering method or an ion plating method, the introduced gas is preferably a mixed gas of argon and oxygen. The volume ratio of argon / oxygen is preferably in the range of 20 to 1, particularly in the range of 4 to 10. In the laser ablation method, a film can be formed even in an atmosphere containing only oxygen.

  In either case, the target is irradiated with a laser or an electron beam to vaporize the target and form a film on the substrate.

  Since the proton conductive material of the present invention has a low film formation temperature, there is little deterioration of the substrate due to the film formation temperature and the oxygen atmosphere. When the substrate is exposed to a high temperature, when the surface is oxidized, it becomes a proton transfer resistance layer. For example, when a fuel cell is manufactured, the output decreases. Further, when the base material is softened, it is easily deformed and handling becomes difficult. Further, since the film forming temperature is low, there is an effect that the equipment cost and the manufacturing cost can be reduced. Since the membrane (proton conductive material) is amorphous, the precipitation of impurities and stress concentration at the grain boundary is reduced, and partial membrane peeling is reduced. Similarly, as compared with a crystalline film such as a perovskite type, the growth rate on the substrate surface is uniform and the surface smoothness is excellent. In addition, since almost no pinholes are generated, hydrogen gas does not move to the oxygen electrode side as it is, and moves as protons, so that there is an effect that a high-performance electrolyte membrane can be provided.

  Embodiments of the present invention will be described below.

Three plate-like palladium (Pd) substrates each having a vertical and horizontal length of 15 mm and a thickness of 1 mm were set in a holder inside a vacuum chamber equipped with a synthetic quartz glass window for laser transmission. Next, the inside of the vacuum chamber was evacuated, and the temperature of the holder was heated to 200 ° C. to heat the palladium substrate. The oxygen partial pressure in the chamber was adjusted to 0.91 Pa (7 × 10 ⁻³ Torr) by controlling the flow rate of oxygen with a mass flow meter. In this state, a raw material SrCeO ₃ sintered body (diameter 20 mm, thickness 5 mm) is irradiated with a KrF excimer laser (energy 500 mJ, frequency 5 Hz) through a laser irradiation window for 30 minutes to form a proton conductive thin film with a thickness of 1 μm. A film was formed on the substrate.

  For one sample, thin film XRD (X-Ray Diffraction) was measured at an incident angle of 0.5 ° using Kα rays of a Cu target. The result is shown in figure 2. The peak position was about 29 °, and the width of the diffraction pattern, the so-called half-value width 10 was about 5 ° at the midpoint between the peak maximum point 9 and the baseline 8.

  Another sample was dissolved and subjected to ion-coupled plasma spectroscopy (ICP analysis) and oxygen content analysis. As a result, Sr was 20.0 atomic%, Ce was 20.4 atomic%, and the balance was oxygen. The atomic ratio Sr: Ce: O slightly deviated from 1: 1: 3.

  A 2 mm square palladium thin film was formed by electron beam evaporation to a thickness of 0.1 μm on the proton conductive film of the remaining one sample through a stainless steel mask to form a sandwich structure. The palladium thin film becomes an oxygen electrode. A sample was prepared by attaching lead wires to the oxygen electrode and the substrate.

  The proton conductive structure was evaluated using this sample. The above structure was placed in a closed container with a temperature of 400 ° C and a hydrogen pressure of 0.1 MPa (1 atm), and a potential of 1 volt (V) was applied between the Pd substrate and the Pd thin film. Current flowed. On the other hand, when a potential of 1 volt (V) was applied in a closed vessel at 400 ° C. and 0.1 MPa (1 atm) in nitrogen, only a current of 0.1 mA could be observed. This revealed that the thin film has proton conductivity that allows protons (hydrogen ions) to pass through.

Subsequently, the performance as a fuel cell was evaluated with the same sample. With the above structure, at a temperature of 400 ° C, hydrogen at a concentration of 2% by volume is supplied to the Pd substrate side at 0.4 L / min, and dry air is supplied to the Pd thin film side at 0.4 L / min to obtain a battery output at 0.3 V. When measured, it was 10 mW / cm ^{2 as shown in} Table 1, and it was confirmed that the fuel cell functions well.

Three plate-like palladium (Pd) substrates each having a vertical and horizontal length of 15 mm and a thickness of 1 mm were set in a holder inside a vacuum chamber equipped with a synthetic quartz glass window for laser transmission. Next, the inside of the vacuum chamber was evacuated, and the temperature of the holder was heated to 200 ° C. to heat the palladium substrate. The oxygen partial pressure in the chamber was adjusted to 0.91 Pa (7 × 10 ⁻³ Torr) by controlling the flow rate of oxygen with a mass flow meter. In this state, the raw material SrCe _0.9 Yb _0.1 O ₃ sintered body (diameter 20 mm, thickness 5 mm) is irradiated with a KrF excimer laser (energy 500 mJ, frequency 5 Hz) for 30 minutes through a laser irradiation window, and a proton with a thickness of 1 μm. A conductor thin film was formed on the substrate.

  For one sample, thin film XRD was measured at an incident angle of 0.5 ° using Kα rays of a Cu target. As shown in Fig. 3, a figure that seems to be mostly amorphous was obtained. The highest peak position was about 29 °, and the half width was about 5 °, which was similar to Example 1.

  Another sample was dissolved and ion-coupled plasma spectroscopy (ICP analysis) and oxygen content analysis were performed. Sr was 20.0 atomic%, Ce was 18.1 atomic%, Yb was 1.9 atomic%, and the balance was oxygen. .

  A 2 mm square palladium thin film was formed by electron beam evaporation to a thickness of 0.1 μm on the proton conductive film of the remaining one sample through a stainless steel mask to form a sandwich structure. The palladium thin film constituted an oxygen electrode, and lead wires were attached to the oxygen electrode and the substrate.

  The proton conductive structure was evaluated using this sample. The above structure was placed in a closed container with a temperature of 400 ° C and a hydrogen pressure of 0.1 MPa (1 atm), and a potential of 1 volt (V) was applied between the Pd substrate and the Pd thin film. Current flowed. On the other hand, when a potential of 1 volt (V) was applied in a closed vessel at 400 ° C. and 0.1 MPa (1 atm) in nitrogen, only a current of 0.1 mA could be observed. This revealed that the thin film has proton conductivity that allows protons (hydrogen ions) to pass through.

Subsequently, the performance as a fuel cell was evaluated. Measure the battery output at 0.3V by flowing 2% hydrogen concentration by 0.4L / min to the Pd substrate side at a temperature of 400 ° C and flowing dry air at 0.4L / min to the Pd thin film side. As a result, as shown in Table 1, it was 10 mW / cm ² , and it was confirmed that the fuel cell functions well.

Three plate-like palladium (Pd) substrates each having a vertical and horizontal length of 15 mm and a thickness of 1 mm were set in a holder inside a vacuum chamber equipped with a synthetic quartz glass window for laser transmission. Next, the inside of the vacuum chamber was evacuated, and the temperature of the holder was heated to 350 ° C., thereby heating the palladium substrate. The oxygen partial pressure in the chamber was adjusted to 0.91 Pa (7 × 10 ⁻³ Torr) by controlling the flow rate of oxygen with a mass flow meter. In this state, the raw material SrCe _0.9 Yb _0.1 O ₃ sintered body (diameter 20 mm, thickness 5 mm) is irradiated with a KrF excimer laser (energy 500 mJ, frequency 5 Hz) for 30 minutes through a laser irradiation window, and a proton with a thickness of 1 μm. A conductor thin film was formed on the substrate.

  For one sample, thin film XRD was measured at an incident angle of 0.5 ° using Kα rays of a Cu target. As shown in FIG. 4, a broad peak peculiar to the amorphous phase was at about 28 °, and the half width was about 6 °. A sharp peak was found at about 29 °, and this peak was found to be based on the perovskite phase. In this embodiment, since the substrate temperature is increased during the film formation of the proton conductive material, a perovskite phase is generated in addition to the amorphous phase, and the two phases coexist.

  When another sample was dissolved and ion-coupled plasma spectroscopy (ICP analysis) and oxygen content analysis were performed, Sr was 19.8 atomic%, Ce was 18.1 atomic%, Yb was 2.0 atomic%, and the balance was oxygen .

  A 2 mm square palladium thin film was formed by electron beam evaporation to a thickness of 0.1 μm on the proton conductive film of the remaining one sample through a stainless steel mask to form a sandwich structure. The palladium thin film constituted an oxygen electrode, and a sample was prepared by attaching lead wires to the oxygen electrode and the base material.

  The proton conductive structure was evaluated using this sample. The above structure was placed in a closed container with a temperature of 400 ° C and a hydrogen pressure of 0.1 MPa (1 atm), and a potential of 1 volt (V) was applied between the Pd substrate and the Pd thin film. Current flowed. On the other hand, when a potential of 1 volt (V) was applied in a closed vessel at 400 ° C. and 0.1 MPa (1 atm) in nitrogen, only a current of 0.1 mA could be observed. This revealed that the thin film has proton conductivity that allows protons (hydrogen ions) to pass through.

Subsequently, the performance as a fuel cell was evaluated. Measure the battery output at 0.3V by flowing 2% hydrogen concentration by 0.4L / min to the Pd substrate side at a temperature of 400 ° C and flowing dry air at 0.4L / min to the Pd thin film side. As a result, it was 10 mW / cm ² as shown in Table 1, and it was confirmed that it functions well as a fuel cell.

Three plate-like palladium (Pd) substrates each having a vertical and horizontal length of 15 mm and a thickness of 1 mm were set in a holder inside a vacuum chamber equipped with a synthetic quartz glass window for laser transmission. Next, the inside of the vacuum chamber was evacuated, and the temperature of the holder was heated to 200 ° C. to heat the palladium substrate. The oxygen partial pressure in the chamber was adjusted to 0.91 Pa (7 × 10 ⁻³ Torr) by controlling the flow rate of oxygen with a mass flow meter. In this state, the raw material SrZr _0.9 Yb _0.1 O ₃ sintered body (diameter 20 mm, thickness 5 mm) is irradiated with a KrF excimer laser (energy 500 mJ, frequency 5 Hz) for 30 minutes through a laser irradiation window, and a proton conductor of 1 μm. A thin film was deposited on the substrate.

  For one sample, thin film XRD was measured at an incident angle of 0.5 ° using Kα rays of a Cu target. The results are shown in FIG. The highest part of the peak was in the vicinity of about 30 °, and the full width at half maximum was about 5 °. This peak is a symmetrical diffraction pattern. The reason why the highest position deviates from other examples is probably due to the influence of Zr.

  Another sample was dissolved and ion-coupled plasma spectroscopy (ICP analysis) and oxygen content analysis were performed. As a result, Sr was 20.0 atomic%, Zr was 18.1 atomic%, Yb was 1.9 atomic%, and the balance was oxygen. .

  A 2 mm square palladium thin film with a thickness of 0.1 μm was formed by electron beam evaporation on the remaining proton conductive film of the sample through a stainless steel mask to form a sandwich structure. The palladium thin film constituted an oxygen electrode, and lead wires were attached to the oxygen electrode and the substrate.

  The proton conductive structure was evaluated using this sample. When the above structure is placed in a sealed container with a temperature of 400 ° C and a hydrogen pressure of 0.1 MPa (1 atm), a potential of 1 volt (V) is applied between the Pd substrate and the Pd thin film, resulting in 0.3 mA. Current flowed. On the other hand, when a potential of 1 volt (V) was applied in a closed vessel of 400 MPa at 0.1 MPa (1 atm) in nitrogen, only a current of 0.01 mA could be observed. This revealed that the thin film has proton conductivity that allows protons (hydrogen ions) to pass through.

Subsequently, the performance as a fuel cell was evaluated with the same sample. Measure the battery output at 0.3V by flowing 2% hydrogen concentration by 0.4L / min to the Pd substrate side at a temperature of 400 ° C and flowing dry air at 0.4L / min to the Pd thin film side. As a result, it was 1 mW / cm ² as shown in Table 1, and it was confirmed that it functions well as a fuel cell.

Three plate-like palladium (Pd) substrates each having a vertical and horizontal length of 15 mm and a thickness of 1 mm were set in a holder inside a vacuum chamber equipped with a high-frequency sputter deposition source. Next, the inside of the vacuum chamber was evacuated, and the temperature of the holder was heated to 200 ° C. to heat the palladium substrate. The oxygen partial pressure in the chamber was adjusted to 6.5 Pa (5 × 10 ⁻² Torr) by controlling the flow rate of oxygen with a mass flow meter. In that state, a raw material SrCe _0.95 Yb _0.05 O ₃ sintered body (diameter 100 mm, thickness 5 mm) was subjected to high-frequency sputtering (power 600 mW) for 2 hours to form a 1 μm proton conductor thin film on the substrate. .

  For one sample, thin film XRD was measured at an incident angle of 0.5 ° using Kα rays of a Cu target. The results are shown in FIG. The peak position was about 28 °, and the full width at half maximum was about 4 °.

  Another sample was dissolved and ion-coupled plasma spectroscopy (ICP analysis) and oxygen content analysis were performed. Sr was 10 atomic%, Ce was 25 atomic%, Yb was 3 atomic%, and the balance was oxygen. .

  A 2 mm square palladium thin film was formed by electron beam evaporation to a thickness of 0.1 μm on the proton conductive film of the remaining one sample through a stainless steel mask to form a sandwich structure. The palladium thin film constituted an oxygen electrode, and lead wires were attached to the oxygen electrode and the substrate.

  The proton conductive structure was evaluated using this sample. When the above structure was installed in a closed container with a temperature of 400 ° C and a hydrogen pressure of 0.1 MPa (1 atm), a potential of 1 volt (V) was applied between the Pd substrate and the Pd thin film. Current flowed. On the other hand, when a potential of 1 volt (V) was applied in a closed vessel at 400 ° C. and 0.1 MPa (1 atm) in nitrogen, only a current of 0.1 mA could be observed. This revealed that the thin film has proton conductivity that allows protons (hydrogen ions) to pass through.

Subsequently, the performance as a fuel cell was evaluated. Measure the battery output at 0.3V by flowing 2% hydrogen concentration by 0.4L / min to the Pd substrate side at a temperature of 400 ° C and flowing dry air at 0.4L / min to the Pd thin film side. As a result, it was 8 mW / cm ^{2 as} shown in Table 1, and it was confirmed that the fuel cell functions well.

(Comparative Example 1)
Three plate-like palladium (Pd) substrates each having a vertical and horizontal length of 15 mm and a thickness of 1 mm were set in a holder inside a vacuum chamber equipped with a synthetic quartz glass window for laser transmission. Next, the inside of the vacuum chamber was evacuated, and the temperature of the holder was heated to 750 ° C., thereby heating the palladium substrate. The oxygen partial pressure in the chamber was adjusted to 0.91 Pa (7 × 10 ⁻³ Torr) by controlling the flow rate of oxygen with a mass flow meter. In this state, the raw material SrCe _0.9 Yb _0.1 O ₃ sintered body (diameter 20 mm, thickness 5 mm) is irradiated with a KrF excimer laser (energy 500 mJ, frequency 5 Hz) for 30 minutes through a laser irradiation window, and a proton with a thickness of 1 μm. A conductor thin film was formed on the substrate.

  For one sample, thin film XRD measurement was performed at an incident angle of 0.5 ° using Kα rays of a Cu target. The results are shown in FIG. As a result, a sharp peak peculiar to the perovskite phase was observed. However, the amorphous phase could not be detected by this method.

  When another sample was dissolved and ion-coupled plasma spectroscopy (ICP analysis) and oxygen content analysis were performed, Sr was 19.8 atomic%, Ce was 18.1 atomic%, Yb was 2.0 atomic%, and the balance was oxygen .

  A 2 mm square palladium thin film with a thickness of 0.1 μm was formed by electron beam evaporation on the remaining proton conductive film of the sample through a stainless steel mask to form a sandwich structure. The palladium thin film constituted an oxygen electrode, and lead wires were attached to the oxygen electrode and the substrate.

  The proton conductive structure was evaluated using this sample. In the obtained structure, the Pd substrate and the Pd thin film were short-circuited in nitrogen at room temperature. 10 pieces were measured for reproducibility check, but all were short-circuited. It is thought that the membrane was damaged because the substrate was softened and deformed, and the stress due to the difference in thermal expansion coefficient between the Pd substrate and the proton conductive material was larger due to the large temperature change (750 ° C → room temperature). .

  The proton conductive material and conductive structure obtained in the present invention can be used for a hydrogen separation membrane, a hydrogen detector, a humidity sensor, etc. in addition to a fuel cell.

It is a conceptual sectional view of a fuel cell using the proton conductive material of the present invention. 2 is an X-ray diffraction pattern of the proton conductive material obtained in Example 1 of the present invention. 3 is an X-ray diffraction pattern of the proton conductive material obtained in Example 2 of the present invention. 4 is an X-ray diffraction pattern of the proton conductive material obtained in Example 3 of the present invention. 6 is an X-ray diffraction pattern of the proton conductive material obtained in Example 4 of the present invention. 6 is an X-ray diffraction pattern of the proton conductive material obtained in Example 5 of the present invention. 2 is an X-ray diffraction pattern of the proton conductive material obtained in Comparative Example 1. FIG.

Explanation of symbols

1 Base material 2 Oxygen electrode
3 Proton conductive material 4 Fuel cell
5 Load 6 Ammeter
7 Voltmeter 8 Baseline
9 Peak maximum 10 Half width

Claims (9)

At least one first element selected from the group consisting of Mg, Ca, Sr and Ba;
At least one second element selected from the group consisting of Ce, Zr, Ti and Hf;
A material with an amorphous structure composed of oxygen,
The amorphous structure is the position of the first peak of the diffraction pattern of the material between 25 ° and 35 ° in the X-ray diffraction measurement using CuKα rays,
The proton conductive material is characterized in that the half width of the peak is 2 ° or more. At least one first element selected from the group consisting of Mg, Ca, Sr and Ba;
At least one second element selected from the group consisting of Ce, Zr, Ti and Hf;
A third element in which a part of the second element is replaced with at least one selected from the group consisting of Sc, Y and a lanthanoid;
A material with an amorphous structure composed of oxygen,
The amorphous structure is the position of the first peak of the diffraction pattern of the material between 25 ° and 35 ° in the X-ray diffraction measurement using CuKα rays,
The proton conductive material is characterized in that the half width of the peak is 2 ° or more. In addition to the first peak in the X-ray diffraction measurement, Ri near between peak position 28 ° and 32 °, to claim 1 or 2, characterized in that it has a second peak sharper than the first peak The proton conductive material described. The proton conductive material has a composition of 8 to 30 atomic% of the first element,
8-30 atomic percent of the second element,
4. The proton conductive material according to claim 1, wherein the balance is oxygen. The proton conductive material has a composition of 8 to 30 atomic% of the first element,
8-30 atomic percent of the second element, except that a part of the second element is replaced by 0.1-3 atomic percent of the whole with the third element,
4. The proton conductive material according to claim 2, wherein the balance is oxygen.   6. The proton conductive material according to claim 1, wherein a thickness of the proton conductive material is 0.05 μm or more and 5 μm or less.   7. A proton conductive structure, wherein the proton conductive material according to claim 1 is formed on a hydrogen permeable substrate.   A fuel cell using the proton conductive material according to any one of claims 1 to 6.   The proton conductive material according to any one of claims 1 to 6 is vapor-phased on a hydrogen permeable substrate in a reduced pressure oxygen atmosphere having a film forming temperature of 500 ° C or lower and a room temperature or higher and an atmosphere of 0.13kPa (1Torr) or lower. A method for producing a proton conductive structure, comprising forming a film.

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