TW201937509A - Solid electrolyte assembly - Google Patents

Abstract

A solid electrolyte assembly (10), formed by joining: a polycrystalline solid electrolyte (11) having oxide ion conductivity; and a mixed conduction electrode layer (12), which is laminated on the solid electrolyte (11) so as to be in contact and which has oxide ion conductivity and electron conductivity. The material constituting the solid electrolyte (11) and the material constituting the mixed conduction electrode layer (12) are uniaxially oriented in the direction of lamination of the solid electrolyte (11) and the mixed conduction electrode layer (12). The c-axis of the material constituting the solid electrolyte (11) and the c-axis of the material constituting the mixed conduction electrode layer (12) are preferably both oriented along the direction of lamination.

Description

Solid electrolyte joint

The present invention relates to a solid electrolyte joined body having oxide ion conductivity. The solid electrolyte joined body of the present invention is used in various fields in which oxygen ion conductivity is utilized.

Various electrolytes of oxide ion conductivity are known in the art. The solid electrolyte is used in various fields, for example, as an oxygen permeable element, an electrolyte of a fuel cell, and a gas sensor. For example, Patent Document 1 discloses an electrolyte membrane for an electrochemical cell comprising the formula: La _1-X Sr _X Ga _1-Y Mg _Y O ₃ (wherein, X=0.05 to 0.3, Y=0.025~) An oxide ion conductor having a compositional composition of 0.3) and having a perovskite crystal structure. The electrolyte membrane has a columnar crystal structure grown in a vertical direction on the film surface and grown to the surface of the film. The 112 direction of the columnar crystal structure grown to the surface of the film is aligned in the vertical direction with respect to the film surface.

Patent Document 2 describes a crystal orientation ceramic having a vicinity of a joint interface in which a first layer containing La ₂ SiO ₅ as a main component and a second layer containing La ₂ Si ₂ O ₇ as a main component are brought into contact with each other. A silicate of apatite type crystal structure in which the c-crystal is aligned in the vertical direction with respect to the original joint interface.

Patent Document 3 describes an electrolyte-electrode assembly in which a solid electrolyte containing an apatite-type composite oxide is interposed between an anode-side electrode and a cathode-side electrode. An intermediate layer in which an oxide ion conduction exhibits an isotropic property is interposed between the cathode side electrode and the solid electrolyte. The intermediate layer contains cerium oxide doped with cerium, lanthanum, cerium or lanthanum. The solid electrolyte contains La _x Si ₆ O _1.5X+12 (8≦X≦10). It is described in the same document that the power generation performance of the solid oxide fuel cell is improved according to the electrolyte-electrode assembly.
Prior art document patent document

Patent Document 1: Japanese Laid-Open Patent Publication No. 2008-10411. Patent Document 2: International Patent Publication No. 2012/015061 Patent Document 3: Japanese Patent Laid-Open Publication No. 2013-51101

As described in Patent Documents 1 to 3, various devices using a solid electrolyte of oxide ion conductivity have been proposed. However, when the device is evaluated as a whole, it is not considered that the oxide ion conduction originally possessed by the solid electrolyte is sufficiently enhanced. Sex.

Accordingly, an object of the present invention is to provide an apparatus which can sufficiently utilize the oxide ion conductivity originally possessed by a solid electrolyte.

In order to solve the problem, the inventors of the present invention conducted intensive studies and found that the solid electrolyte of the oxide ion conductive material and the material are bonded to each other to form a bonded body, thereby sufficiently enhancing the solid electrolyte. Oxide ion conductivity.

The solid electrolyte bonding system of the present invention is based on the above findings, in which a polycrystalline solid electrolyte having an oxide ion conductivity is laminated with the solid electrolyte to have a mixture of oxide ion conductivity and electron conductivity. The conductive electrode layer is joined, and the material constituting the solid electrolyte and the material constituting the mixed conductive electrode layer are aligned along a direction of lamination of the solid electrolyte and the mixed conductive electrode layer. The above problem is solved by providing such a solid electrolyte joined body.

Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments thereof. As shown in FIG. 1, the solid electrolyte joined body 10 of the present invention includes a layer (hereinafter referred to as "solid electrolyte layer") 11 including a solid electrolyte. The solid electrolyte layer 11 contains a solid electrolyte having oxide ion conductivity above a specific temperature. An electrode layer (hereinafter referred to as "mixed conductive electrode layer") 12 having mixed conductivity laminated on the solid electrolyte layer 11 is bonded to one surface of the solid electrolyte layer 11. In the embodiment shown in Fig. 1, the solid electrolyte layer 11 is in direct contact with the mixed conductive electrode layer 12, and no other layers are interposed therebetween. The mixed conductive electrode layer 12 contains a material having oxide ion conductivity and electron conductivity. The solid electrolyte assembly 10 is composed of the solid electrolyte layer 11 and the mixed conductive electrode layer 12.

As shown in FIG. 1, in the two surfaces of the solid electrolyte layer 11, the metal electrode 13 can be further disposed on the surface opposite to the surface on which the conductive electrode layer 12 is disposed. In this case, the device 20 is configured by sequentially arranging the solid electrolyte layer 11, the mixed conductive electrode layer 12, and the metal electrode 13. In the embodiment shown in Fig. 1, the solid electrolyte layer 11 is in direct contact with the metal electrode 13, and no other layer is interposed therebetween.

In FIG. 1, the solid electrolyte layer 11 and the mixed conductive electrode layer 12 are shown in different sizes, but the relationship between the two is not limited thereto. For example, the solid electrolyte layer 11 and the mixed conductive electrode layer 12 may have the same size. Similarly to the solid electrolyte layer 11 and the metal electrode 13, the two may be the same size, or for example, the solid electrolyte layer 11 may be larger than the metal electrode 13.

As a result of the investigation by the present inventors, it has been found that in the solid electrolyte joined body 10, the electric resistance between the solid electrolyte layer 11 and the mixed conductive electrode layer 12 can be greatly reduced by bonding the mixed conductive electrode layer 12 to the solid electrolyte layer 11. Further, in order to lower the electric resistance of the device 20, it is considered that it is first important to increase the oxide ion conductivity of the solid electrolyte layer 11, but if the material constituting device 20 having a high oxide ion conductivity is used, it is judged that the entire device 20 is The tendency of the resistor to become higher. In particular, when a solid electrolyte layer containing an oxide of cerium, which is one of the materials having a high oxide ion conductivity, is used as the solid electrolyte layer, the electric resistance becomes high, and the oxygen permeation rate in the solid electrolyte joined body 10 is lowered. The tendency. Although the reason is not clear at present, the inventors believe that the reason is that the electrical resistance of the interface between the solid electrolyte layer and the electrode or the mixed conductive electrode layer disposed adjacent thereto is high.

In order to solve the problem that the electric resistance of the device 20 is increased and the oxygen permeation rate is lowered, the present inventors conducted intensive studies, and as a result, it has been found that it is effective to use an oxide ion conductivity and an electron conductivity. The mixed conductive electrode layer 12 is a layer disposed adjacent to the solid electrolyte layer 11 which is a layer having oxide ion conductivity, and the material constituting the solid electrolyte layer 11 and the material constituting the mixed conductive electrode layer 12 are all along the solid electrolyte layer 11. It is aligned with the lamination direction of the mixed conductive electrode layer 12 in one axis. Thereby, the low temperature actuation of the device 20 can be achieved, or the device 20 having a higher oxygen permeability can be obtained. On the other hand, even when the material constituting the solid electrolyte layer 11 and/or the material constituting the mixed conductive electrode layer 12 is unaligned or the crystals of the two layers are aligned, they are laminated in the alignment directions. When the directions are not uniform, the electric resistance at the interface between the solid electrolyte layer 11 and the mixed conductive electrode layer 12 becomes high, and high oxide ion conductivity cannot be exhibited.

In order to align the material constituting the solid electrolyte layer 11 and the material constituting the mixed conductive electrode layer 12 along the lamination direction, for example, the solid electrolyte layer 11 serving as the substrate is heated to 300 ° C to 700 ° C while controlling the oxygen. A film in which the conductive electrode layer 12 is mixed is formed on the solid electrolyte layer 11 by a physical vapor deposition method or a chemical vapor deposition method in a pressure environment, and local epitaxial growth may be performed. Further, an axial alignment film of the mixed conductive electrode layer 12 may be formed on the solid electrolyte layer 11 by atomic layer deposition (ALD). However, it is not limited to these methods.

Whether the material constituting the solid electrolyte layer 11 and the material constituting the mixed conductive electrode layer 12 are one-axis alignment can be judged by the cross-sectional observation by the TEM (transmission electron microscope) of the joint interface, the solid electrolyte layer 11 and the mixed conductive electrode layer. The lattice constant or the interplanar spacing of 12 can be calculated from the diffraction pattern obtained by X-ray diffraction measurement while swinging.

From the viewpoint of obtaining higher oxide ion conductivity, it is preferred that the c-axis of the material constituting the solid electrolyte layer 11 and the c-axis of the material constituting the mixed conductive electrode layer 12 are both conducted along the solid electrolyte layer 11 and mixed. The lamination direction of the electrode layer 12 is aligned. Here, the direction in which the c-axis of each of the solid crystals of the solid electrolyte corresponding to the c-axis along the lamination direction coincides with the direction of the laminated layer.

The solid electrolyte layer 11 is an electric conductor in which an oxide ion becomes a carrier. As the solid electrolyte constituting the solid electrolyte layer 11, a polycrystalline material is used. As such a material, various materials known to date as materials having oxide ion conductivity can be cited. For example, yttrium zirconia (YSZ) or lanthanum gallate (LaGaO ₃ ) may be mentioned.

In particular, when an oxide of cerium is used as the material constituting the solid electrolyte layer 11, it is preferable in terms of oxide ion conductivity. Examples of the oxide of cerium include a composite oxide containing cerium and gallium, a composite oxide containing cerium, magnesium or cobalt, and a composite oxide containing cerium and molybdenum. In particular, in terms of high oxide ion conductivity, an oxide ion conductive material containing a composite oxide of cerium and lanthanum is preferably used.

Examples of the composite oxide of cerium and lanthanum include an apatite-type composite oxide containing cerium and lanthanum. As the apatite-type composite oxide, in terms of high oxide ion conductivity, it is preferably a trivalent element, a tetravalent element, and an O, and the composition thereof is La _x Si ₆ O. _1.5x+12 (X represents the number of 8 or more and 10 or less). When the apatite-type composite oxide is used as the solid electrolyte layer 11, it is preferable to make the c-axis coincide with the thickness direction of the solid electrolyte layer 11. The optimum composition of the apatite type composite oxide is La _9.33 Si ₆ O ₂₆ . The composite oxide can be produced, for example, by the method described in JP-A-2013-51101.

Other examples of the material constituting the solid electrolyte layer 11 include a composite oxide represented by the formula (1): A _{9.33 + x} [T _{6.00 - y} M _y ] O _{26.0 + z} . The composite oxide is also an apatite type structure. In the formula, A is selected from one or more elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Be, Mg, Ca, Sr, and Ba. Wherein T is Si or Ge or an element comprising both of them. The M in the formula is selected from one or more elements selected from the group consisting of B, Ge, Zn, Sn, W, and Mo. From the viewpoint of improving the c-axis orientation, M is preferably one or more elements selected from the group consisting of B, Ge, and Zn.

From the viewpoint of improving the degree of alignment and the oxide ion conductivity, x in the formula is preferably -1.00 or more and 1.00 or less, more preferably 0.00 or more and 0.70 or less, still more preferably 0.45 or more and 0.65 or less. The y in the formula is preferably 0.40 or more and 3.00 or less, more preferably 0.40 or more and 2.00 or less, and still more preferably 0.40 or more and 1.00, from the viewpoint of the position of the T element in the apatite type crystal lattice. the following. From the viewpoint of maintaining electrical neutrality in the apatite type crystal lattice, z in the formula is preferably -3.00 or more and 2.00 or less, more preferably -2.00 or more and 1.50 or less, and still more preferably -1.00 or more. And 1.00 or less.

In the above formula, the ratio of the molar number of A to the molar number of M, in other words, (9.33+x)/y in the above formula, holds the space occupancy ratio in the apatite-type crystal lattice. It is preferably 3.00 or more and 26.0 or less, more preferably 6.20 or more and 26.0 or less, still more preferably 12.00 or more and 16.0 or less.

In the composite oxide represented by the above formula (1), when a composite oxide represented by La _9.33+x [T _6.00-y M _y ]O _26.0+z, which is a composite oxide of cerium, is used, it is oxidized. It is preferable from the viewpoint that the ion conductivity of the substance becomes higher. Specific examples of the composite oxide represented by La _9.33+x [T _6.00-y M _y ]O _26.0+z include La _9.33+x (Si _4.70 B _1.30 )O _26.0+z and La _9.33+x (Si). _4.70 Ge _1.30 )O _26.0+z , La _9.33+x (Si _4.70 Zn _1.30 )O _26.0+z , La _9.33+x (Si _4.70 W _1.30 )O _26.0+z , La _9.33+x (Si _4.70 Sn _1.30 )O _26.0+x , La _9.33+x (Ge _4.70 B _1.30 )O _26.0+z, and the like. The composite oxide represented by the above formula (1) can be produced, for example, according to the method described in International Patent Publication WO2016/111110.

The thickness of the solid electrolyte layer 11 is preferably 10 nm or more and 1000 μm or less, more preferably 50 nm or more and 700 μm or less, and still more preferably 100, from the viewpoint of effectively reducing the electric resistance of the solid electrolyte joined body 10. Above nm and below 500 μm. The thickness of the solid electrolyte layer 11 can be measured, for example, using a stylus profiler or an electron microscope.

The mixed conductive electrode layer 12 contains a material having oxide ion conductivity and electron conductivity. In particular, the mixed conductive electrode layer 12 preferably comprises a material having a catalytic action. The catalyst action described herein acts to reduce oxygen molecules (O ₂ ) to oxide ions (O ²⁻ ) or to oxidize oxide ions (O ²⁻ ) to oxygen molecules (O ₂ ). As such material, for example, LaCoO _3, or a portion LaMnO _3, etc. The use of other atoms substituted with atoms of the _{(La, Sr) MnO 3,} (La, Sr) CoO 3, (La, Sr) (Co, Fe) O ₃ and the like.

In the solid electrolyte joined body 10, the material constituting the mixed conductive electrode layer 12 and the material constituting the solid electrolyte layer 11 are aligned along the lamination direction of the solid electrolyte layer 11 and the mixed conductive electrode layer 12, thereby making the two layers The resistance at the interface between the 11 and 12 is reduced. In view of making this advantage more remarkable, it is advantageous to achieve lattice matching of the face orthogonal to the alignment direction at the interface between the two layers 11 and 12. For example, when the c-axis constituting the material of each of the layers 11 and 12 is aligned along the lamination direction, it is preferable to achieve lattice matching of the surface orthogonal to the c-axis. In this case, either the lattice constant of the a-axis or the b-axis of the mixed conductive electrode layer 12 or the interval between the faces may be matched with the lattice constant of the solid electrolyte layer 11 or the interval between the faces. Further, even in the case where the matching between the solid electrolyte layer 11 and the mixed conductive electrode layer 12 cannot be achieved, the lattice constant or the interplanar spacing of the mixed conductive electrode layer 12 can be made according to the solid electrolyte layer by heating the solid electrolyte joined body 10. 11 is matched with the lattice constant or the surface spacing orthogonal to the alignment direction, thereby causing crystal growth of one axis alignment. From this point of view, when the lattice constant of the surface perpendicular to the c-axis of the material constituting the solid electrolyte layer 11 is a, and the surface interval of (010) of the mixed conductive electrode layer 12 is d, a It is preferably 9.28 Å or more and 9.84 Å or less. Further, d is preferably 4.54 Å or more and 5.04 Å or less, more preferably 4.60 Å or more and 4.97 Å or less, and still more preferably 4.64 Å or more and 4.92 Å or less.

The lattice constant and the interplanar spacing d of the solid electrolyte layer 11 and the mixed conductive electrode layer 12 are diffraction peaks obtained by X-ray diffraction measurement by swinging the mixed conductive electrode layer 12 after being joined to the solid electrolyte layer 11. Calculated. At this time, the X-ray diffraction measurement conditions are such that Cu-Kα ray is used, the diffraction angle (2θ/θ) is 10° to 140°, the inclination angle (χ oscillating) is -5° to 45°, and the in-plane rotation (f) Swing) is 0~360°.

Further, when the type or composition ratio of the element contained in the sample is determined, the lattice constant a or the surface interval d can be calculated based on the diffraction data of the standard substance such as ICSD (Inorganic Crystal Structure Library). For example, when the crystal form of the solid electrolyte layer 11 is hexagonal and the lattice constant a is 9.60 Å, the surface interval of the (110) plane of the solid electrolyte layer 11 is 4.80 Å. In the case where the (010) plane spacing of the mixed conductive electrode layer 12 is d=4.70 Å, it is considered that since the lattice mismatch of the plane orthogonal to the c-axis is low, it is 2.2%, so the mixed conductive electrode layer 12 is Partial epitaxial growth on the solid electrolyte layer 11.

In the interface between the solid electrolyte layer 11 and the mixed conductive electrode layer 12, the material constituting the mixed conductive electrode layer 12 is preferably a perovskite type oxide from the viewpoint of achieving lattice matching of the surface orthogonal to the alignment direction. . In particular, when the material constituting the solid electrolyte layer 11 is the one represented by the above formula (1), if the material constituting the mixed conductive electrode layer 12 is a perovskite-type oxide, lattice matching can be smoothly achieved. . In this case, if the space group of the perovskite-type oxide is R-3c, lattice matching can be achieved more smoothly, which is preferable.

In particular, it is preferable to use a compound represented by the general formula (2): ABO ₃ as a material constituting the mixed conductive electrode layer 12 to further improve oxide ion conductivity. In the formula, A is preferably one or two or more metal elements selected from the group consisting of, for example, La, Sr, Ba, and Ca, and at least one of the most preferable metal elements, La and Sr. B is preferably one or two or more metal elements selected from the group consisting of, for example, Co, Ni, Mn, Cr, Ti, Fe, and Cu, and at least one of the most preferable metal elements, Co and Ni. In particular, the material represented by the formula (2) is preferably a composite oxide containing La, Sr, Co and Ni.

Among the composite oxides represented by the formula (2), those represented by La _0.6 Sr _0.4 Co _0.9 Ni _0.1 O _3-δ are particularly preferred.

The mixed conductive electrode layer 12 containing the composite oxide represented by the general formula (2) can be formed on one surface of the solid electrolyte layer 11 by, for example, various thin film formation methods. Examples of the film formation method include a physical vapor deposition method, a chemical vapor deposition method, and the like. When the physical vapor deposition method is used, the mixed conductive electrode layer 12 can be formed more smoothly. Among the physical vapor deposition methods, a PLD (Pulsed Laser Deposition) method is particularly preferred.

As a result of the study by the inventors, it has been found that the mixed conductive electrode layer 12 can effectively reduce the electric resistance with the solid electrolyte layer 11 as long as it has a specific thickness. Specifically, the thickness of the mixed conductive electrode layer 12 bonded to the solid electrolyte layer 11 in the stacking direction is preferably 80 nm or more, more preferably 100 nm or more, and still more preferably 100 nm or more and 1000 nm or less. The thickness of the mixed conductive electrode layer 12 can be measured by a stylus profiler or an electron microscope.

The metal electrode 13 formed on the side opposite to the mixed conductive electrode layer 12 via the solid electrolyte layer 11 has an advantage of being easily formed and having high catalytic activity, and is preferably composed of a platinum group element. Examples of the platinum group element include platinum, rhodium, ruthenium, palladium, osmium, and iridium. These elements may be used alone or in combination of two or more. Further, a cermet containing a platinum group element may be used as the metal electrode 13.

The solid electrolyte bonded body 10 and the apparatus 20 of the embodiment shown in Fig. 1 can be preferably produced, for example, by the method described below. First, the solid electrolyte layer 11 is produced by a known method. In the production, for example, the method described in Japanese Patent Laid-Open Publication No. 2013-51101 or International Patent Publication No. WO2016/111110, which is hereby incorporated by reference.

Next, a mixed conductive electrode layer 12 is formed on one of the two faces of the solid electrolyte layer 11. In the formation of the mixed conductive electrode layer 12, for example, the PLD method previously described can be used. Specifically, in order to align the material constituting the solid electrolyte layer 11 and the material constituting the mixed conductive electrode layer 12 along the lamination direction of the solid electrolyte layer 11 and the mixed conductive electrode layer 12, as long as the PLD previously described is used. When the mixed conductive electrode layer 12 is formed on one surface of the solid electrolyte layer 11, the solid electrolyte layer 11 may be heated to a specific temperature. The heating temperature is preferably set to, for example, 600 ° C or more and 700 ° C or less in terms of smoother one-axis alignment.
After the mixed conductive electrode layer 12 is formed in this manner, the metal electrode 13 is formed on the surface of the solid electrolyte layer 11 opposite to the surface on which the conductive electrode layer 12 is formed. In the formation of the metal electrode 13, for example, a paste containing particles of a platinum group metal is used. The paste is applied onto the surface of the solid electrolyte layer 11 to form a coating film, and the coating film is fired to form an electrode including a porous body. The calcination conditions can be set to a temperature of 600 ° C or higher and a time of 30 minutes or longer and 120 minutes or shorter. The environment can be set to an oxygen-containing environment such as the atmosphere.

The target solid electrolyte joined body 10 and the apparatus 20 can be obtained by the above method. The device 20 obtained in this manner is preferably used as, for example, an oxygen permeable member, an oxygen sensor, or a solid electrolyte fuel cell, by virtue of its higher oxide ion conductivity. Regardless of the use of the device 20, it is advantageous to use the mixed conductive electrode layer 12 as the cathode, i.e., as the electrode that causes the reduction reaction of oxygen. For example, when the device 20 is used as the oxygen permeable element, the metal electrode 13 is connected to the anode of the direct current power source, and the mixed conductive electrode layer 12 is connected to the cathode of the direct current power source between the mixed conductive electrode layer 12 and the metal electrode 13. Apply a specific DC voltage. Thereby, on the side of the mixed conductive electrode layer 12, oxygen receives electrons to generate oxide ions. The generated oxide ions move in the solid electrolyte layer 11 to reach the metal electrode 13. The oxide ions reaching the metal electrode 13 release electrons into oxygen. By such a reaction, the solid electrolyte layer 11 can transmit oxygen contained in the environment on the side of the mixed conductive electrode layer 12 to the electrode 13 side through the solid electrolyte layer 11. Further, if necessary, a collector layer containing a conductive material such as platinum may be formed on at least one surface of the surface of the mixed conductive electrode layer 12 and the surface of the metal electrode 13.

From the viewpoint of increasing the amount of oxygen permeation, the applied voltage is preferably set to be 0.1 V or more and 4.0 V or less. When a voltage is applied between the two electrodes, it is preferred that the oxide ion conductivity of the solid electrolyte layer 11 is sufficiently improved. For example, the oxide ion conductivity is expressed by conductivity, and is preferably 1.0 × 10 ^-3 S/cm or more. Therefore, it is preferable to maintain the entire solid electrolyte layer 11 or the apparatus 20 at a specific temperature. Although the holding temperature depends on the material of the solid electrolyte layer 11, it is generally set to a range of 300 ° C or more and 600 ° C or less. By using the device 20 under the above conditions, oxygen contained in the environment on the side of the mixed conductive electrode layer 12 can be transmitted to the metal electrode 13 side through the solid electrolyte layer 11.

When the device 20 is used as the limiting current type oxygen sensor, the oxide ions generated on the side of the mixed conductive electrode layer 12 are moved to the side of the metal electrode 13 via the solid electrolyte layer 11, so that an electric current is generated. Since the current value depends on the oxygen concentration on the side of the mixed conductive electrode layer 12, the oxygen concentration on the side of the mixed conductive electrode layer 12 can be measured by measuring the current value.

Hereinabove, the present invention has been described based on preferred embodiments thereof, but the present invention is not limited to the above embodiments. For example, in the above embodiment, the mixed conductive electrode layer 12 is disposed only on one surface of the solid electrolyte layer 11, and instead, the mixed conductive electrode layer 12 may be opposed to the solid electrolyte layer 11 as described in the following embodiments. An additional mixed conductive electrode layer 12 is disposed on the surface. In the case where the mixed conductive electrode layer 12 is disposed on the surface of the solid electrolyte layer 11 opposite to the mixed conductive electrode layer 12, each of the mixed conductive electrode layers 12 may be the same or different. In this case, it is preferable that the material constituting the solid electrolyte layer 11 and the material constituting one mixed conductive electrode layer 12 and the material constituting the other mixed conductive electrode layer 12 are aligned one-axis along the stacking direction.
[Examples]

Hereinafter, the present invention will be described in more detail by way of examples. However, the scope of the invention is not limited to the embodiment. Unless otherwise stated, "%" means "% by mass".

[Example 1]
In the present embodiment, the solid electrolyte joined body 10 and the apparatus 20 of the structure shown in Fig. 1 were produced in accordance with the following steps (1) to (4).
(1) Production of Solid Electrolyte Layer 11 The powder of La ₂ O _{3 and} the powder of SiO ₂ were blended so that the molar ratio became 1:1, and ethanol was added thereto, followed by mixing by a ball mill. The mixture was dried, pulverized by a mortar, and calcined at 1,650 ° C for 3 hours in a platinum atmosphere using a platinum crucible. Ethanol was added to the calcined product, and pulverization was carried out by a ball mill to obtain a calcined powder. The calcined powder was placed in a 20 mmf shaper and pressed in one direction for uniaxial forming. Further, cold uniform pressure pressurization (CIP) was performed at 700 MPa for 1 minute to form pellets. This granular shaped body was heated in the air at 1600 ° C for 3 hours to obtain a particulate sintered body. The sintered body was subjected to powder X-ray diffraction measurement and chemical analysis, and as a result, it was confirmed that it was a structure of La ₂ SiO ₅ .

800 mg of the obtained granules and 140 mg of B ₂ O ₃ powder were placed in a covered crucible, and heated in an atmosphere at 1550 ° C (in-furnace ambient temperature) for 50 hours. By this heating, B ₂ O ₃ vapor is generated in the crucible, and B ₂ O ₃ vapor is reacted with the particles, and then annealed in an atmosphere of 1600 ° C to obtain the target solid electrolyte layer 11 . The solid electrolyte layer 11 is in La _9.33+x [Si _6.00-y B _y ]O _26.0+z , x=0.57, y=0.96, z=0.37, and the molar ratio of La to B is 10.03 (hereinafter, The compound is simply referred to as "LSBO"). The oxide ion conductivity at 500 ° C was 4.22 × 10 ^-2 S / cm. The thickness of the solid electrolyte layer 11 was 350 μm. It was confirmed by a polarizing microscope that the solid electrolyte layer 11 contained polycrystals.

(2) Production of Mixed Conductive Electrode Layer 12 The mixed conductive electrode layer 12 was formed on one surface of the solid electrolyte layer 11 produced in (1) in the following order.
The solid electrolyte layer 11 and the target La _0.6 Sr _0.4 Co _0.9 Ni _0.1 O _3-δ (hereinafter, this material is simply referred to as "LSCNO") are placed in a chamber of the PLD device, and a vacuum is applied to the chamber. The heating was carried out in advance at 600 °C. Thereafter, oxygen is introduced into the chamber to control the environment so as to be 5.5×10 ⁻⁴ torr, and then the KrF excimer laser is used to deposit the evaporated particles generated by the laser ablation on the solid electrolyte layer 11 . The conductive electrode layer 12 is mixed and formed. The mixed conductive electrode layer 12 thus obtained was confirmed to contain polycrystals by TEM cross-section observation of the interface with the solid electrolyte layer 11. Further, it was confirmed that the (110) plane of the solid electrolyte layer 11 coincides with the gap of the (010) plane of the mixed conductive electrode layer 12, and the c-axis of the material constituting the solid electrolyte layer 11 and the c-axis of the material constituting the mixed conductive electrode layer 12 are confirmed. They all align along the stacking direction. Further, X-ray diffraction measurement was performed while swinging, and as a result, it was confirmed that the mixed conductive electrode layer 12 has a perovskite-type oxide having a space group of R-3c. Further, the surface interval of the (110) plane of the solid electrolyte layer 11 calculated based on the lattice constant obtained from the diffraction pattern was 4.80 Å, and the surface interval of the (010) plane of the mixed conductive electrode layer 12 was 4.68 Å. The lattice mismatch is 2.45%.

(3) Production of Metal Electrode 13 The metal electrode 13 is formed on the surface of the solid electrolyte layer 11 produced in (1) on the side opposite to the surface on which the mixed conductive electrode layer 12 is formed. In the formation of the metal electrode 13, a sputtering method using a platinum target is used. The platinum film formed on the surface of the solid electrolyte layer 11 on the opposite side to the surface on which the conductive electrode layer 12 was formed by sputtering was annealed at 600 ° C for 1 hour, whereby the metal electrode 13 was obtained. The metal electrode 13 has a thickness of 100 nm.

(4) Production of Current Collecting Layer A platinum paste was applied to the surface of the mixed conductive electrode layer 12 and the metal electrode 13 to form a coating film. These coating films were calcined in the air at 600 ° C for 1 hour to obtain a current collecting layer.

[Embodiment 2]
The step of (2) of the first embodiment was carried out instead of the step (3) of the first embodiment, and the apparatus 20 for mixing the conductive electrode layers 12 was disposed on each surface of the solid electrolyte layer 11.

[Comparative Example 1]
In the step (2) of Example 1, the mixed conductive electrode layer 12 was formed into a film at room temperature. Except for this, the solid electrolyte joined body 10 and the apparatus 20 were obtained in the same manner as in the first embodiment. In the solid electrolyte joined body 10, it was confirmed by X-ray diffraction measurement that the mixed conductive electrode layer 12 was not aligned in one axis.

[Comparative Example 2]
In the present comparative example, a coating film containing LSCNO was applied to each surface of the solid electrolyte layer 11 obtained in the step (1) of Example 1 to form a coating film, and the coating film was calcined at 700 ° C for 1 hour. Thereby, a mixed conductive electrode layer 12 having a thickness of 300 nm or more is formed.

[Comparative Example 3]
In the present comparative example, the solid electrolyte layer 11 subjected to the step (1) of Example 1 was formed. Next, the step (3) of the first embodiment is carried out, and in the solid electrolyte layer 11, a metal electrode 13 containing platinum is formed instead of the mixed conductive electrode layer 12 of the first embodiment. Further, a metal electrode 13 containing platinum is also formed on the opposite side. The metal electrode 13 has a thickness of 100 nm or more.

[Evaluation]
With respect to the apparatus obtained in the examples and the comparative examples, the oxygen permeation rate was measured by the following method. Further, it was confirmed by X-ray diffraction measurement whether or not the crystals of the solid electrolyte layer 11 and the mixed conductive electrode layer 12 were aligned. The results of these are shown in Table 1 below.

[Measurement of oxygen permeability rate]
The measurement was carried out at 600 °C. Air was supplied to the mixed conductive electrode layer 12 side of the apparatus at 200 ml/min, and nitrogen gas (N ₂ ) was supplied to the metal electrode 13 side at 200 ml/min, and 1.0 V was applied between the mixed conductive electrode layer 12 and the metal electrode 13. DC voltage. An oxygen concentration meter was attached to the metal electrode 13 side, and the change in oxygen concentration in the environment on the side of the metal electrode 13 before and after the application of the voltage was measured, and the oxygen permeation rate (ml·cm ^-2 · min ^-1 ) was calculated. Further, the oxygen permeability efficiency was calculated according to the formula [oxygen permeability measured by the oxygen concentration meter] / [oxygen permeability measured by current density] × 100.

[Table 1]

As is apparent from the results shown in Table 1, the solid electrolyte joined body obtained in each of the examples and the apparatus having the same have a large oxygen permeation rate and a high oxygen permeation efficiency.
[Industrial availability]

According to the present invention, there is provided a solid electrolyte joined body having a high oxygen transmission rate. By using the solid electrolyte joined body, the low temperature operation of the apparatus or the increase in the oxygen supply amount can be achieved.

10‧‧‧Solid electrolyte joint

11‧‧‧Solid electrolyte layer

12‧‧‧ mixed conductive electrode layer

13‧‧‧Metal electrode

20‧‧‧ device

Fig. 1 is a schematic cross-sectional view showing the embodiment of the apparatus for using a solid electrolyte joined body of the present invention in the thickness direction.

Claims (13)

A solid electrolyte joined body obtained by joining a polycrystalline solid electrolyte having oxide ion conductivity to a mixed conductive electrode layer which is laminated with the solid electrolyte and has oxide ion conductivity and electron conductivity. and The material constituting the solid electrolyte and the material constituting the mixed conductive electrode layer are aligned along a direction of lamination of the solid electrolyte and the mixed conductive electrode layer. The solid electrolyte joined body of claim 1, wherein the mixed conductive electrode layer is polycrystalline. The solid electrolyte joined body according to claim 1 or 2, wherein the c-axis of the material constituting the solid electrolyte and the c-axis of the material constituting the mixed conductive electrode layer are aligned along the lamination direction. The solid electrolyte joined body of claim 1 or 2, wherein the solid electrolyte is an apatite type composite oxide. The solid electrolyte joined body of claim 1 or 2, wherein the solid electrolyte comprises the formula: A _9.33+x [T _6.00-y M _y ]O _26.0+z (wherein A is selected from La, Ce, Pr, An element of one or more of the group consisting of Nd, Sm, Eu, Gd, Tb, Dy, Be, Mg, Ca, Sr, and Ba; wherein T is Si or Ge or an element comprising both; In the formula, M is a composite oxide represented by one or two or more elements selected from the group consisting of B, Ge, Zn, Sn, W, and Mo, wherein x is -1.00 or more and 1.00 or less. In the formula, y is 0.40 or more and 3.00 or less, wherein z is -3.00 or more and 2.00 or less, and the ratio of the molar number of A to the molar number of M is 3.00 or more and 26.0 or less. The solid electrolyte joined body according to claim 1 or 2, wherein a surface interval of (010) of the mixed conductive electrode layer is 4.54 Å or more and 5.04 Å or less. The solid electrolyte joined body of claim 1 or 2, wherein the mixed conductive electrode layer is a perovskite type oxide. The solid electrolyte joined body of claim 7, wherein the space group of the perovskite type oxide is R-3c. The solid electrolyte joined body according to claim 1 or 2, wherein the mixed conductive electrode layer comprises a composite oxide of La, Sr, Co and Ni. The solid electrolyte joined body according to claim 1 or 2, wherein the mixed conductive electrode layer bonded to the solid electrolyte has a thickness of 100 nm or more along the lamination direction. The solid electrolyte joined body according to claim 1 or 2, wherein the solid electrolyte joined body is provided with a metal electrode on a surface opposite to a surface on which the mixed conductive electrode layer is disposed. The solid electrolyte joined body according to claim 1 or 2, wherein in the solid electrolyte joined body, mixed conduction is the same as or different from that of the mixed conductive electrode layer on a surface opposite to a surface on which the mixed conductive electrode layer is disposed Electrode layer. A solid electrolyte joined body according to claim 1 or 2, which is used as an oxygen permeable member, an oxygen sensor or a solid electrolyte fuel cell.