JP2003288904A - Electrochemical element, oxygen concentrator, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical element, an oxygen concentrator, and a fuel cell, easy to manufacture and decreasing the resistance of an electrode. <P>SOLUTION: An anode layer 11 which is a stacked electrode having three layer electrode structure is constituted by forming an oxide electrode layer 31 on the surface of a ceramic substrate 7, a mixed electrode layer 33 on the surface of the oxide electrode layer 31, and a metal electrode layer 35 on the surface of the mixed electrode layer 33. The ceramic substrate 7 is an oxygen ion-permeable solid electrolyte layer. The oxide electrode layer 31 is an oxide layer having oxygen decomposition capability. The mixed electrode layer 33 is composed of a mixed material of a metallic material of the metal electrode 35 and an oxide material. The metal electrode layer 35 is composed of the metallic material. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrochemical device, an oxygen concentrator, and a fuel cell which can be used, for example, in the medical field or industrial applications.

[0002]

2. Description of the Related Art Heretofore, an oxygen concentrator for extracting oxygen from air and a fuel cell for extracting electricity from a fuel gas by an electrochemical reaction using a ceramic electrochemical element have been known.

This type of electrochemical device comprises a solid electrolyte layer composed of a dense solid electrolyte and a pair of catalyst electrode layers (anode layer and cathode layer) provided on both sides so as to sandwich the solid electrolyte layer. It is configured. In a fuel cell, for example, the fuel cell air electrode (air-side electrode) is usually composed of an oxide electrode made of an oxide material such as lanthanum manganite.

In addition to the technique of providing the oxide electrode, a technique of providing a metal layer on the oxide electrode (see, for example, Japanese Patent Laid-Open No. 2000-70706) has also been proposed.

[0005]

However, in the case of the technique of using an oxide electrode as the above-mentioned air electrode for a fuel cell, in general, the electron conductivity in the plane direction of the oxide electrode is low, so that the conductivity is reduced. The low electron conductivity was compensated for by using the separator provided as a conductive member and bringing the separator and the oxide electrode into contact with each other at many contacts.

However, even if the number of contacts of the separator is increased to increase the contact density, there is a problem that the resistance cannot be sufficiently reduced. Further, in order to secure good contact points (particularly a large number of contact points) with a separator, extremely high dimensional accuracy is required, so that there is also a problem that its manufacture is not easy.

On the other hand, in the case of the technique of providing the metal layer on the oxide electrode, the resistance can be lowered as compared with the case of only the oxide electrode, but it is not always sufficient. The present invention has been made in view of the above points, and an object of the present invention is to provide an electrochemical element, an oxygen concentrator, and a fuel cell that can be easily manufactured and can sufficiently reduce the resistance of electrodes.

[0008]

Means for Solving the Problems and Effects of the Invention (1) In the invention of claim 1, an electrode is provided on a solid electrolyte base material, and an electrochemical element made of ceramic for pumping oxygen has oxygen resolution. A laminated electrode having an oxide electrode formed on the solid electrolyte substrate and a mixed electrode formed on the oxide electrode using a mixed material of a metal material and an oxide material. Is characterized by.

In the present invention, as an electrode of an electrochemical device,
Since a laminated electrode in which a mixed electrode is formed on an oxide electrode (having at least a two-layer electrode structure) is used, compared with a conventional oxide electrode only or an oxide electrode and a metal electrode laminated, As shown in the experimental example, the electric resistance can be greatly reduced (that is, the conductivity can be increased). Thereby, power consumption can be reduced.

Further, since the laminated electrode of the present invention has higher conductivity than the conventional one, it is possible to reduce the number of contacts contacting the electrodes. Further, for example, when a contact is formed by processing a separator that covers the periphery of an electrode, it is not easy to manufacture it because securing a good number of contacts requires extremely high dimensional accuracy. Since the number of contacts can be reduced to an extremely small number such as one, there is a remarkable effect that the manufacturing is easy.

It is assumed that the structure of the present invention reduces the resistance of the electrode because the mixed electrode increases the surface area of the conductive material (metal) in contact with the oxide electrode. As the oxide, the oxide material used for the oxide electrode can be used. (2) The invention of claim 2 is characterized in that the laminated electrode further comprises a metal electrode on the mixed electrode.

In the present invention, as an electrode of an electrochemical device,
Since a laminated electrode in which a mixed electrode is formed on an oxide electrode and a metal electrode is further provided on the mixed electrode (at least a three-layer electrode structure) is used, the invention of claim 1 is As a result, the resistance value of the electrode is further reduced. This allows
The power consumption can be further reduced.

The metal material used for the mixed electrode can be used as the material for the metal electrode. (3) In the invention of claim 3, the laminated electrode is formed on one surface or both surfaces of the solid electrolyte substrate.

The present invention exemplifies the constitution of an electrochemical device. For example, in the case of an oxygen concentrator, a structure in which the laminated electrodes are formed on both sides (anode and cathode) of the solid electrolyte substrate can be adopted. Further, for example, in the case of a fuel cell, a structure in which the laminated electrode is formed on one side (cathode) of the solid electrolyte substrate can be adopted.

(4) The invention of claim 4 is characterized in that the solid electrolyte substrate is a flat substrate or a substrate bent in a tubular shape. The present invention exemplifies the constitution of the electrochemical device. For example, in the case of using a flat fixed electrolyte substrate, an anode (or anode) is provided on one surface and a cathode (or cathode) is provided on the other surface, or an anode (or anode) is provided on one surface.
Also, a configuration provided with a cathode (or a cathode) can be adopted.

Further, for example, when a cylindrical fixed electrolyte substrate is used, it is possible to adopt a structure in which an anode (or anode) is provided on one surface and a cathode (or cathode) is provided on the other surface. It should be noted that it is possible to employ a cylindrical one whose one end is closed or one whose both ends are open.

(5) In the invention of claim 5, as the material of the solid electrolyte substrate, fully stabilized zirconia, partially stabilized zirconia, lanthanum gallate, and a rare earth element or an alkaline earth metal element are doped (added). One of the cerium oxides is used.

The present invention exemplifies the material of the solid electrolyte substrate. In the present invention, as the material of the solid electrolyte substrate, fully stabilized zirconia and partially stabilized zirconia,
Lanthanum gallate or cerium oxide doped with a rare earth element or an alkaline earth metal element can be used.

The fully-stabilized zirconia or the partially-stabilized zirconia is zirconia to which rare earths (eg, scandium, yttria, lanthanum, calcium, etc.) are added. (6) The invention of claim 6 is characterized in that a composite oxide or a mixture of the composite oxide and a material of the solid electrolyte substrate is used as a material of the oxide forming the oxide electrode. .

The present invention exemplifies the material of the oxide forming the oxide electrode. The use of this material has an advantage that oxygen gas is rapidly ionized and taken into the solid electrolyte. Here, as the complex oxide, for example, Ln _(1-x) Sr _x MnO _3- δ, Ln _(1-x
) Sr _x CoO _3- δ, Ln _(1-x) Sr _x FeO _3- δ, and L
n _(1-x) Sr _x Co _y Fe _{( 1-y)} O _{3 −} δ (at least 0 <x <1, 0 <y <1, δ is oxygen deficiency, Ln = La) , Sm, Nd, Gd, Pr) can be adopted.

(7) In the invention of claim 7, as the material of the mixed electrode, a mixture of at least one selected from Ag, Pd and Pt and a complex oxide is used. The present invention is
This is an example of the material forming the mixed electrode. The use of this material has an advantage that electrons can be smoothly transferred between the metal particles and the composite oxide particles.

Here, as the complex oxide, for example, L
n _(1-x) Sr _x MnO _3- δ, Ln _{(1-x )} Sr _x CoO _3- δ,
Ln _(1-x) Sr _x FeO _3- δ, and Ln _(1-x) Sr _x Co _y
At least one selected from Fe _{( 1-y)} O _3- δ (provided that
0 <x <1, 0 <y <1, δ is oxygen deficiency, Ln = L
a, Sm, Nd, Gd, Pr) can be adopted.

(8) The invention of claim 8 is characterized in that the complex oxide contained in the oxide electrode is different from the complex oxide contained in the mixed electrode. Here, the reason why the composite oxide contained in the oxide electrode is different from the composite oxide contained in the mixed electrode is that different materials have different properties such as seizability and oxygen decomposing ability, and therefore the performance of the entire electrode is improved. This is because a preferable combination can be selected.

(9) In the invention of claim 9, the complex oxide contained in the oxide electrode is Ln _{(1 -x)} Sr _x MnO ₃ -δ.
And the complex oxide contained in the mixed electrode is Ln
_{At least one selected from (1-x)} Sr _x CoO _3- δ, Ln _(1-x) Sr _x FeO _3- δ, and Ln _(1-x) Sr _x Co _y Fe _{(1- y)} O _3- δ. Be of one type (however, 0 <x <1, 0 <y <
1, δ are oxygen deficiency, Ln = La, Sm, Nd, Gd,
Pr).

The present invention exemplifies combinations of different complex oxides.
It is shown. That is, the composite contained in the oxide electrode
Ln that is an oxide_(1-x)Sr_xMnO_3-δ is zirconia
Since it has low reactivity, it can be baked at over 1000 ℃.
Is a complex oxide contained in the mixed electrode.
Ln_(1-x)Sr_xCoO_3-δ, Ln _(1-x)Sr_xFeO
_3-δ, and Ln_(1-x)Sr_xCo_yFe_(1-y)O_3-δ, etc.
Has a high reactivity with zirconia,
Demonstrate performance by causing a chemical reaction when baked at a temperature
Although not possible, the ability to decompose oxygen is
The characteristics of the Co-based and Fe-based are higher.

Therefore, in the present invention, by combining both composite oxides, it is intended to realize a high oxygen resolution and a high image sticking property as required. That is,
M for oxide electrodes that will not burn unless the temperature is over 1000 ° C
The n-type mixed electrode that burns at 850 ° C. contains Co.
By mixing the system and the Fe system, preferable characteristics can be obtained.

(10) The invention of claim 10 is characterized in that at least one selected from Ag, Pd, and Pt is used as the material of the metal electrode. The present invention exemplifies the material of the metal electrode. By using the material of the present invention, there is an advantage that it assists the electron conduction of the metal particles contained in the mixed electrode and reduces the electric resistance in the planar direction.

(11) In the invention of claim 11, the amount of oxide added to the mixed electrode is 5 to 5 of the mixed electrode.
It is characterized in that it is in the range of 0% by weight. The present invention exemplifies the amount of oxide added to the mixed electrode.
In the present invention, since the amount of oxide added is 5% by weight or more, it has the properties that are clearly different from those of the metal electrode, and has the advantage of increasing the number of contact points between the metal particles and the composite oxide particles. Further, since the amount of the oxide added is 50% by weight or less, there is an advantage that the bondability with the metal electrode is good and peeling is difficult.

(12) Invention of Claim 12 (oxygen concentrator)
Is characterized in that the electrochemical device according to any one of claims 1 to 11 is used. The oxygen concentrator of the present invention is
Since the electrochemical device having the above-mentioned laminated electrode is used,
Low electrode resistance and low power consumption. Further, when the separator is used as a contact, there is an advantage that the separator can be easily processed.

(13) Invention of Claim 13 (fuel cell)
Is characterized in that the electrochemical device according to any one of claims 1 to 11 is used. Since the fuel cell of the present invention uses the electrochemical element having the above-mentioned laminated electrode, the electrode resistance is low and the power consumption is low. Further, when the separator is used as a contact, there is an advantage that the separator can be easily processed.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments (Examples) of the electrochemical device, oxygen concentrator, and fuel cell of the present invention will be described below.
Will be explained. (Example 1) a) First, the oxygen concentrator of Example 1 will be described.

The oxygen concentrator of this embodiment uses an oxygen enrichment stack having a large number of cells (which is a basic unit for performing oxygen enrichment), and supplies air to the oxygen enrichment stack (and thus each cell). A device for concentrating and extracting oxygen in the air. As shown in FIG. 1, the cell 1 is
For example, a circular device (as viewed from above in the figure) is one in which an electrochemical element 3 and a separator 5 made of an electronic conductor are laminated and arranged.

In other words, the electrochemical element 3 has, for example, a disk-shaped ceramic substrate (solid electrolyte layer made of oxygen ion conductive ceramics) 7 and a disk-shaped ceramic substrate formed on one surface (upper surface: upper part of the drawing) of the same. It comprises an anode layer 9 and a disk-shaped cathode layer 11 formed on the other surface (lower surface: lower part of the figure).

The separator 5 is made of a ceramic base material 7.
On the upper surface side of the first separator 13 arranged to cover the anode layer 9, and on the lower surface side of the ceramic substrate 7, the cathode layer 1
1 and a second separator 15 arranged so as to be opposed thereto. A first space 17 is formed by the first separator 13, and oxygen is taken out through the communication hole 19. On the anode layer 9 side of the first separator 13, an anode-side contact 21 protruding toward the anode layer 9 side and contacting the anode layer 9 is formed.
Are provided, for example, at one location.

On the other hand, the second space 23 covered with the second separator 15 is communicated with the surrounding atmosphere and air is introduced therein. On the cathode layer 11 side of the second separator 15, a cathode side contact 25 that protrudes toward the cathode layer 11 side and contacts the cathode layer 11 is provided, for example, at one location.

In particular, since the separator 5 functions as a partition wall for air or oxygen gas and has conductivity, a lead for electrically connecting the power supply (DC power supply) 27 and the anode layer 9 or the cathode layer 11 to each other. Function as a department. That is,
The first separator 13 electrically connects the anode side of the power source 27 and the anode layer 9 of the electrochemical element 3, and the second separator 15 connects the cathode side of the power source 27 and the cathode layer 11 of the electrochemical element 3. It is electrically connected.

B) Next, the structure of the electrochemical device 3, which is the main part of this embodiment, will be described with reference to FIG. Incidentally, FIG.
FIG. 3 is a cross-sectional view showing a part of the electrochemical device 3 by breaking and enlarging it. In this embodiment, since the anode layer 9 and the cathode layer 11 have the same structure, the cathode layer 11 will be described as an example here.

As shown in FIG. 2, an oxide electrode layer 31 is formed on the surface of the ceramic substrate 7, a mixed electrode layer 33 is formed on the surface of the oxide electrode layer 31, and a mixed electrode layer 33 is formed on the surface of the mixed electrode layer 33. Is formed with a metal electrode layer 35, which constitutes the cathode layer 11 which is a laminated electrode having a three-layer electrode structure.

Of these, the ceramic substrate 7 is a solid electrolyte layer composed of stabilized zirconia to which, for example, rare earth is added, and is a solid electrolyte layer through which oxygen ions can pass, and its composition is, for example, 10 wt% Sc and 1 wt%. % Ce and the balance stabilized zirconia (10Sc1CeSZ: ScS below)
The composition of Z) can be adopted.

The oxide electrode layer 31 is an oxide layer having an oxygen decomposing property, and is composed of, for example, lanthanum manganite and stabilized zirconia to which rare earths are added. The composition is, for example, La _0.6 Sr _0.4 MnO.
A composition of ₃ (50% by weight) and ScSZ (50% by weight) can be adopted.

The mixed electrode layer 33 is composed of a mixed material of a metal material of the metal electrode layer 35 and an oxide material (different from the oxide electrode layer 31). The composition is, for example, Ag (80% by weight) and Sm _0.5 Sr _0.5 CoO ₃ (2
0% by weight) can be used.

The metal electrode layer 35 is made of a metal material. As the composition, for example, Ag (100% by weight) can be adopted. In the present embodiment, the anode layer 9 and the cathode layer 11 have the same three-layer electrode structure as the laminated structure, but in addition to this, a single layer of platinum electrode may be used as the anode layer 9.

C) Next, a method for manufacturing the above-mentioned electrochemical device 3 will be briefly described. First, a material comprising scandia-stabilized zirconia powder (ScSZ), a binder and an organic solvent is mixed to prepare a slurry. Using the slurry, a green sheet is formed by a doctor blade method, the green sheet is cut into a predetermined shape, degreased at 250 to 350 ° C., and then 1450.
The ceramic substrate 7 is manufactured by firing at a temperature of ˜1500 ° C.

Next, the surface of the ceramic substrate 7 (both sides)
Then, the oxide electrode layer 31 is formed. Specifically, La
A paste obtained by mixing _0.6 Sr _0.4 MnO ₃ , ScSZ and a binder was printed on a predetermined place on the ceramic substrate 7 using a screen and baked at 1130 ° C. to form the oxide electrode layer 31. Form.

Next, the surface of the oxide electrode layer 31 (both sides)
Then, the mixed electrode layer 33 is formed. Specifically, Ag and S
A paste prepared by mixing m _0.5 Sr _0.5 CoO ₃ (oxide) and a binder was used to form an oxide electrode layer 31 using a screen.
By printing on the top and baking at 850 ° C,
The mixed electrode layer 33 is formed.

Next, on the surface (both sides) of the mixed electrode layer 33,
The metal electrode layer 35 is formed. Specifically, a paste obtained by mixing Ag, carbon, and a binder is printed on the mixed electrode layer 33 using a screen and baked at 850 ° C. to form the metal electrode layer 35.

As a result, the electrochemical device 3 is provided with the anode layer 9 and the cathode layer 11 having the three-layer electrode structure of the oxide electrode layer 31, the mixed electrode layer 33, and the metal electrode layer 35 on the upper and lower surfaces of the ceramic substrate 7. Is formed. d) Next, the operation of the cell 1 will be described with reference to FIG.

In the present example, an air pump, not shown, is used for the oxygen enrichment stack, and thus for the second cell of cell 1.
Air (pre-heated) is fed into the space 23. The ambient temperature is also kept at 750 ° C., for example. As shown in FIG. 1, since the anode layer 9 and the cathode layer 11 of the electrochemical device 3 of each cell 1 are connected to the power source 27, the power source 27
Therefore, the anode layer 9 side should have a high potential (+), for example, 0
A voltage of ~ 1.5V is applied. Along with that, the cathode layer 1
Air is supplied to the second space 23 on the first side.

When the voltage is applied, the cathode layer 11 electrolyzes oxygen in the air in the second space 23 to generate oxygen ions. The oxygen ions pass through the ceramic substrate 7 by the voltage applied between the cathode layer 11 and the anode layer 9 and the anode layer 9 side (first space 17 side).
Leading to. In the anode layer 9, the oxygen ions (O ²⁻ ) are recombined into oxygen molecules, which are concentrated in the first space 17.

In other words, oxygen is the first from the second space 23 side.
It is pumped to the space 17 side, so that the first space 1
100% oxygen will be supplied to the 7 side.
The oxygen enriched stack is for efficiently generating high concentration oxygen by stacking a large number of the cells 1 described above.

F) Next, the effect of the oxygen concentrator equipped with the electrochemical device 3 of this embodiment will be described. Since the anode layer 9 and the cathode layer 11 of the electrochemical device 3 of this embodiment have a three-layer electrode structure of the oxide electrode layer 31, the mixed electrode layer 33, and the metal electrode layer 35, the electrical resistance is low. Therefore, power consumption can be reduced.

Further, since it has high conductivity, it is possible to reduce the number of contacts 21 and 25 contacting the anode layer 9 and the cathode layer 11 as compared with the conventional case. That is, a part of the separator 5 is projected inward (toward the anode layer 9 and the cathode layer 11 side) to make the contact 21,
When used as 25, the contacts 21, 25
The number of can be reduced.

Further, in order to secure a good number of good contact points 21, 25 in the separator 5, it is not easy to manufacture because extremely high dimensional accuracy is required, but in the present invention, the number of the contact points 21, 25 is not limited. Since it can be reduced, there is a remarkable effect that the manufacturing is easy. (Embodiment 2) Next, an oxygen concentrator of Embodiment 2 will be described.

A) The oxygen concentrator of the second embodiment is different only in the configuration of the electrochemical device, and the other parts are the same as those in the first embodiment. Therefore, only the electrochemical device will be described. As shown in FIG. 3, in the electrochemical device 41 of this embodiment, the oxide electrode layer 45 is formed on the surface of the ceramic substrate 43,
A cathode layer 49 having a two-layer electrode structure in which a mixed electrode layer 47 is formed on the surface of the oxide electrode layer 45 is provided.

The structure of the anode layer (not shown) is the same as that of the cathode layer 49, and the composition and the like of the ceramic substrate 43, the oxide electrode layer 45, and the mixed electrode layer 47 are the same as those in the first embodiment. Therefore, the description thereof will be omitted. b) In this embodiment, as compared with the first embodiment, the cathode layer 49
The resistance between the anode layer and the anode layer is somewhat large, but the same effect as that of the first embodiment is obtained. (Experimental Example 1) Next, an experimental example performed for confirming the effects of the first and second embodiments will be described.

In this experimental example, a 6 mm square ceramic substrate was manufactured in the same manner as in the electrochemical element manufacturing methods of Examples 1 and 2. Then, as Sample No. 1 within the scope of the present invention, on one surface of the ceramic substrate, (oxide electrode layer-mixture electrode layer-metal electrode layer) was prepared in the same manner as in Example 1.
A cathode layer having a three-layer electrode structure was formed, and a platinum electrode was formed as an anode layer on the other surface.

As Sample No. 2 within the scope of the present invention,
On one surface of the ceramic substrate, as in the second embodiment,
A cathode layer having a two-layered electrode structure (oxide electrode layer-mixture electrode layer) is formed. On the other surface, a platinum electrode is formed as an anode layer. Furthermore, the sample No. outside the scope of the present invention (comparative example).
3, a cathode layer having a two-layer electrode structure in which a metal electrode layer is laminated on the oxide electrode layer is formed on one surface of the ceramic substrate, and a platinum electrode is formed as an anode layer on the other surface. did.

In addition, as sample No. 4 outside the scope of the present invention (comparative example), a cathode layer consisting of only the oxide electrode layer was formed on one surface of the ceramic substrate, and the other surface was formed on the other surface. A platinum electrode was formed as the anode layer. And
A current of 0.8 A / cm ² was passed between the anode layer (+) and the cathode layer (−) in the state where each sample was heated to 750 ° C. in a furnace, and at that time, generated between both electrodes. The voltage was measured. The results are shown in Table 1 below.

[0059]

[Table 1] As is clear from Table 1, the sample No. within the scope of the present invention.
When the electrochemical device of Sample No. 1 and Sample No. 2 was used, the voltage was as small as 0.42 V or less (hence the resistance was small),
It turns out to be preferable.

In particular, in the case of the sample No. 1 having the three-layer electrode structure, the voltage is 0.35 V, which is the smallest, and it is understood that it is particularly preferable. That is, it can be seen that when the cathode layer having the three-layer electrode structure is used, the resistance value is greatly reduced and oxygen is efficiently decomposed.

On the other hand, when the electrochemical devices of Sample No. 3 and Sample No. 4 of Comparative Examples outside the scope of the present invention were used, the voltage was as large as 0.52 V or more (hence the resistance was large). It turns out that it is not preferable. (Example 3) Next, a fuel cell of Example 3 will be described.

A) As shown in FIG. 4, the fuel cell of this embodiment has a ceramic substrate 51, an anode layer 53 formed on the upper surface of the ceramic substrate 51, and a cathode layer formed on the lower surface of the ceramic substrate 51. And an electrochemical element 57 composed of 55. Of these, the ceramic substrate 51
Is a layer made of a solid electrolyte having the same composition as in Example 1 above. Further, the anode layer 53 is a mixed electrode formed by using nickel powder and stabilized zirconia powder, and the cathode layer 55 is the oxide electrode layer-mixture electrode layer as in the cathode layer of the first embodiment. A laminated electrode having a three-layer electrode structure of metal electrode layers.

Further, a first space 61 is formed by the first separator 59, and hydrogen is supplied through the communication hole 63. On the anode layer 53 side of the first separator 59, anode side contacts 65 that project toward the anode layer 53 side and contact the anode layer 53 are provided at, for example, a plurality of locations.

On the other hand, the second cover covered with the second separator 67
The space 69 communicates with the surrounding atmosphere and air is introduced therein. On the cathode layer 55 side of the second separator 67,
A cathode-side contact 71 that projects toward the cathode layer 55 side and contacts the cathode layer 55 is provided at one location (less than the anode-side contact 65), for example.

Further, since both separators 59 and 67 function as partition walls for air or hydrogen gas and have conductivity, a lead portion for electrically connecting the resistor 73 and the anode layer 53 or the cathode layer 55. Function as.
That is, the first separator 59 electrically connects the resistor 73 to the anode layer 53 of the electrochemical element 57,
The resistor 73 and the cathode layer 55 of the electrochemical element 57 are electrically connected by the separator 67.

B) In this fuel cell, for example, air containing 20% by weight of oxygen is introduced into the second space 69 formed on the cathode layer 55 side to form the first space formed on the anode layer 53 side.
Hydrogen is introduced into the space 61. Then, in this state, when the anode layer 53 and the cathode layer 55 are connected by the conductive member 75 via the resistor 73, a current flows through the conductive member 75 from the cathode layer 55 side to the anode layer 53 side.

That is, oxygen is decomposed in the cathode layer 55 and oxygen ions are pumped to the anode layer 53 side,
Since it becomes water vapor in the anode layer 53, electrons flow according to the chemical change, and the flow of electrons (hence current)
Can be taken out through the conductive member 75 and the resistor 73.

C) Also in this embodiment, the cathode layer 55
Is a laminated electrode having a three-layer electrode structure of an oxide electrode layer-a mixture electrode layer-a metal electrode layer, and therefore has the advantage that the resistance between the anode layer 55 and the cathode layer 53 is small, and thus the power loss is small. is there. In addition, since the conductivity is high, the number of contacts 71 in contact with the cathode layer 53 can be reduced as compared with the related art.

Further, in order to secure a good number of contacts 71, extremely high dimensional accuracy is required, but in the present embodiment, since the number of contacts 71 can be reduced, the remarkable effect that the manufacture is easy. Play. It is needless to say that the present invention is not limited to the above-mentioned embodiments and can be implemented in various modes without departing from the technical scope of the present invention.

(1) Instead of forming the anode layer and the cathode layer on both sides of the ceramic substrate as in the above-mentioned respective embodiments, for example, as shown in FIG. The layer (or anode layer) 83 and the cathode layer (or cathode layer) 85 may be formed. In this case, both spaces 91 and 93 may be separated by both separators 87 and 89.

(2) Further, as shown in FIG. 6, the ceramic substrate 101 is formed in a cylindrical shape with one side closed, and the spaces 103 and 105 are separated by the inside and the outside of the cylinder, and one side is formed inside the cylinder. The electrode layer (for example, the anode layer) 107 may be formed, and the other electrode layer (for example, the cathode layer) 109 may be formed outside the cylinder. Alternatively, although not shown, without closing the cylinder,
The space may be separated between the inside and the outside of the cylinder.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an electrochemical element of an oxygen concentrator of Example 1 in a broken and enlarged manner.

FIG. 2 is an explanatory diagram showing the operation of the electrochemical device of the oxygen concentrator of Example 1.

FIG. 3 is an explanatory view showing an electrochemical element of the oxygen concentrator of Example 2 in a broken and enlarged manner.

FIG. 4 is an explanatory diagram showing the operation of the electrochemical device of the fuel cell of Example 3.

FIG. 5 is an explanatory diagram showing a configuration of another electrochemical element.

FIG. 6 is an explanatory diagram showing a configuration of still another electrochemical element.

[Explanation of symbols]

1 ... Cell 3, 41 ... Electrochemical element 5, 13, 15, 59, 67, 87, 89 ... Separator 7, 43, 51, 81, 101 ... Ceramic substrate 9, 83 ... -Anode layers 11, 49, 85 ... Cathode layers 21, 25, 65, 71 ... Contact points 31, 45 ... Oxide electrode layers 33, 47 ... Mixed electrode layers 35 ... Metal electrode layers 53 ... Anode layer 55 ... Cathode layer

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Claims (13)

[Claims] 1. A ceramic electrochemical element for providing oxygen on a solid electrolyte substrate for pumping oxygen, comprising: an oxide electrode having oxygen decomposing ability and formed on the solid electrolyte substrate; and a metal material. And a mixed electrode formed on the oxide electrode by using a mixed material of the oxide material and an oxide material. 2. The electrochemical device according to claim 1, wherein the laminated electrode further comprises a metal electrode on the mixed electrode. 3. The electrochemical element according to claim 1, wherein the laminated electrode is formed on one surface or both surfaces of the solid electrolyte substrate. 4. The electrochemical device according to claim 1, wherein the solid electrolyte substrate is a flat substrate or a substrate bent in a tubular shape. 5. A material of the solid electrolyte substrate is one of fully stabilized zirconia, partially stabilized zirconia, lanthanum gallate, and cerium oxide doped with a rare earth element or an alkaline earth metal element. The electrochemical device according to any one of claims 1 to 4, which is characterized. 6. The composite oxide or a mixture of the composite oxide and a material of the solid electrolyte base material is used as a material of the oxide forming the oxide electrode. 5. The electrochemical device according to any one of 5 above. 7. The material of the mixed electrode is Ag, P
The electrochemical device according to any one of claims 1 to 6, wherein a mixture of at least one selected from d and Pt and a complex oxide is used. 8. The electrochemical device according to claim 1, wherein the complex oxide contained in the oxide electrode is different from the complex oxide contained in the mixed electrode. 9. The complex oxide contained in the oxide electrode is Ln _(1-x) Sr _x MnO _3- δ, and the complex oxide contained in the mixed electrode is Ln _(1-x) Sr. _x CoO _3- δ, L
n _(1-x) Sr _x FeO _3- δ, and Ln _(1-x) Sr _x Co _y F
e _(1-y) O _{3- It} is at least one kind selected from δ (where 0 <x <1, 0 <y <1, δ is an oxygen deficiency, L
n = La, Sm, Nd, Gd, Pr), The electrochemical device according to any one of claims 1 to 8, characterized in that 10. The material of the metal electrode is Ag, P
The electrochemical element according to any one of claims 2 to 9, wherein at least one selected from d and Pt is used. 11. The electrochemical device according to claim 1, wherein the amount of oxide added to the mixed electrode is in the range of 5 to 50% by weight of the mixed electrode. 12. An oxygen concentrator using the electrochemical device according to any one of claims 1 to 11. 13. A fuel cell using the electrochemical device according to any one of claims 1 to 11.