JP6311970B2 - Electrode for solid oxide fuel cell, production method thereof, and solid oxide fuel cell - Google Patents

Description

  The present invention relates to an electrode for a solid oxide fuel cell, a method for producing the electrode, and a solid oxide fuel cell. More specifically, the present invention relates to a solid oxide fuel cell electrode having a predetermined intermediate layer and a conductive path layer, a method for producing the same, and a solid oxide fuel cell.

A fuel cell is a device that converts chemical energy into electrical energy through an electrochemical reaction. A solid oxide fuel cell, which is one of such fuel cells, has a three-layer structure in which layers of a fuel electrode, a solid electrolyte, and an air electrode are stacked.
The solid oxide fuel cell can generate electricity by supplying a fuel gas such as hydrogen or hydrocarbon from the outside to the fuel electrode and supplying an oxidant gas such as air to the air electrode. it can.
Further, current collectors are disposed on the electrode surfaces of the fuel electrode and the air electrode. In addition, in order to improve the conductivity between the fuel electrode or air electrode and the current collector, a conductive path is formed by mixing conductive particles in the fuel electrode or air electrode. Formation was difficult.

On the other hand, a solid oxide fuel that forms a conductive path, suppresses an increase in resistance value due to an increase in contact resistance between the fuel electrode and the air electrode and the current collector, and prevents the battery performance from being impaired. A battery has been proposed (see Patent Document 1).
This solid oxide fuel cell has a battery structure having a structure in which a fuel electrode is disposed on one surface and an air electrode on the other surface via an electrolyte, and each fuel is provided on at least one of the fuel electrode and the air electrode. The current collector is formed by printing while leaving an exposed region where the electrode and the air electrode are exposed.

JP 2006-139955 A

  However, the current collector described in Patent Document 1 has a problem of peeling due to a difference in thermal expansion from the fuel electrode and the air electrode. For this reason, there is a problem that the conductivity is not sufficiently improved by providing the current collector.

  The present invention has been made in view of such problems of the prior art. Then, an object of the present invention is to provide a solid oxide fuel cell electrode, a manufacturing method thereof, and a solid oxide fuel cell which have a conductive path layer that is difficult to peel off and have excellent conductivity.

  The inventors of the present invention have made extensive studies in order to achieve the above object. As a result, it has been found that the above object can be achieved by providing a predetermined intermediate layer and conductive path layer, and the present invention has been completed.

That is, the solid oxide fuel cell electrode of the present invention includes an electrode layer disposed in contact with the solid electrolyte layer, on the opposite side across the side and the electrode layer a solid electrolyte layer is disposed in the electrode layer there are, comprises a current collector disposed in contact with the electrode layer, and a conductive path layer disposed on at least a portion of the surface on which the collector electrode layer is disposed, electrode And an intermediate layer disposed between the layer and the conductive path layer.
The conductive path layer is composed of a plurality of conductive path layer material particles made of at least one conductive path layer material of a material having conductivity equivalent to the conductivity of the electrode layer and a material having conductivity higher than that of the electrode layer. The conductive path layer material particles are joined together.
The intermediate layer is composed of an electrode layer material forming the electrode layer and a conductive path layer material, and the content ratio of the conductive path layer material increases as the distance from the conductive path layer decreases in the thickness direction of the intermediate layer. Has an inclined structure.
Another electrode for a solid oxide fuel cell of the present invention is opposite to the electrode layer disposed in contact with the solid electrolyte layer, the side of the electrode layer on which the solid electrolyte layer is disposed, and the electrode layer interposed therebetween. A conductive path layer disposed on at least a part of the surface of the electrode layer on the side where the current collector is disposed, and the electrode layer and the conductive path. And an intermediate layer disposed between the layers.
The conductive path layer is composed of a plurality of conductive path layer material particles made of at least one conductive path layer material of a material having conductivity equivalent to the conductivity of the electrode layer and a material having conductivity higher than that of the electrode layer. The conductive path layer material particles are joined together.
The intermediate layer is composed of an electrode layer material forming the electrode layer and a conductive path layer material, and the content ratio of the conductive path layer material increases as the distance from the conductive path layer decreases in the thickness direction of the intermediate layer. Has an inclined structure.
Further, the intermediate layer does not include a composite material containing at least one component element constituting the electrode layer material and at least one component element constituting the conductive path layer material.
Furthermore, another electrode for a solid oxide fuel cell of the present invention includes an electrode layer disposed in contact with the solid electrolyte layer, a side of the electrode layer on which the solid electrolyte layer is disposed, and an electrode layer sandwiched between the electrode layer and the electrode layer. A conductive path layer disposed on at least a portion of the surface of the electrode layer on the side where the current collector is disposed, and the electrode layer and the conductive layer. And an intermediate layer disposed between the pass layer.
The conductive path layer is composed of a plurality of conductive path layer material particles made of at least one conductive path layer material of a material having conductivity equivalent to the conductivity of the electrode layer and a material having conductivity higher than that of the electrode layer. The conductive path layer material particles are joined together.
The intermediate layer is composed of an electrode layer material forming the electrode layer and a conductive path layer material, and the content ratio of the conductive path layer material increases as the distance from the conductive path layer decreases in the thickness direction of the intermediate layer. Has an inclined structure.
Furthermore, the thickness of the intermediate layer is 0.1 to 2 μm.

  The solid oxide fuel cell of the present invention has the above-described electrode for a solid oxide fuel cell of the present invention and a solid electrolyte layer.

  Furthermore, the method for producing an electrode for a solid oxide fuel cell according to the present invention provides the conductivity of the electrode layer on at least a part of the surface of the electrode layer when producing the electrode for a solid oxide fuel cell according to the present invention. The intermediate layer and the conductive path layer are formed by colliding the conductive path layer material particles made of at least one of the conductive path layer material and the material having the same conductivity as that of the electrode layer and the conductivity of the electrode layer. Manufacturing method.

According to the present invention, the electrode layer, the predetermined current collector, the conductive path layer disposed on at least a part of the surface of the electrode layer on the side where the current collector is disposed, the electrode layer and the conductive path An intermediate layer disposed between the conductive layer and the conductive path layer, at least one of a material having a conductivity equivalent to that of the electrode layer and a material having a conductivity higher than that of the electrode layer The conductive path layer material particles are composed of a plurality of conductive path layer material particles, the conductive path layer material particles are joined to each other, and the intermediate layer includes an electrode layer material that forms an electrode layer, and a conductive path layer material. A structure having a composition gradient structure in which the content ratio of the conductive path layer material increases as the distance from the conductive path layer in the thickness direction of the intermediate layer decreases , or the side on which the current collector of the electrode layer is disposed A conductive path layer disposed on at least a portion of the surface, an electrode layer, An intermediate layer disposed between the conductive path layer and the conductive path layer, wherein the conductive path layer is made of a material having conductivity equivalent to that of the electrode layer and a material having conductivity higher than that of the electrode layer. An electrode layer material comprising a plurality of conductive path layer material particles made of at least one conductive path layer material, the conductive path layer material particles being joined together, and an intermediate layer forming an electrode layer and the conductive path layer The composition has a composition gradient structure in which the content of the conductive path layer material increases as the distance from the conductive path layer in the thickness direction of the intermediate layer decreases, and the intermediate layer includes at least one of the electrode layer materials. A structure not including a composite material containing at least one kind of constituent element and at least one kind of constituent element constituting the conductive path layer material, or at least a part of the surface of the electrode layer on the side where the current collector is disposed A conductive path layer disposed; An intermediate layer disposed between the electrode layer and the conductive path layer, wherein the conductive path layer has a conductivity higher than that of the electrode layer and a material having conductivity equivalent to that of the electrode layer. An electrode layer material comprising a plurality of conductive path layer material particles made of at least one conductive path layer material of the material having a structure in which the conductive path layer material particles are joined to each other, and the intermediate layer forms an electrode layer The conductive path layer material has a composition gradient structure in which the content ratio of the conductive path layer material increases as the distance from the conductive path layer decreases in the thickness direction of the intermediate layer, and the thickness of the intermediate layer is 0.1 It was set as the structure which is -2 micrometers .
Therefore, it is possible to provide a solid oxide fuel cell electrode, a method for manufacturing the same, and a solid oxide fuel cell that have a conductive path layer that does not easily peel off and have excellent conductivity.

1 is a scanning electron microscope (SEM) photograph showing a cross section of an electrode precursor used in Example 1. FIG. FIG. 2 is an explanatory view schematically showing a method of manufacturing the electrode of Example 1. FIG. 3 is an explanatory view schematically showing an electrode of Example 1. As shown in FIG. 4 is a scanning electron microscope (SEM) photograph showing a part of the surface of the electrode of Example 1. FIG. FIG. 5 is a scanning electron microscope (SEM) photograph showing a cross section of a portion surrounded by the surrounding line V shown in FIG. 4 of the electrode of Example 1. FIG. 6 is a scanning electron microscope (SEM) photograph showing a cross section of the vicinity of the surface surrounded by the surrounding line VI shown in FIG. 5 of the electrode of Example 1. FIG. 7 is an explanatory view schematically showing a cross section in the vicinity of the surface of the electrode of Example 1 surrounded by the surrounding line VII shown in FIG. FIG. 8A shows the result of mapping element analysis of zirconium (Zr) by the energy dispersive X-ray analyzer (EDX) in the cross section of the surface vicinity portion of the electrode of Example 1 surrounded by the surrounding line VII shown in FIG. FIG. 8B is a mapping element of nickel (Ni) by an energy dispersive X-ray analyzer (EDX) in the cross section of the vicinity of the surface surrounded by the enveloping line VII shown in FIG. 6 of the electrode of Example 1. FIG. 8C is a result of the analysis, and FIG. 8C is a scanning electron microscope (SEM) photograph showing a cross section of the vicinity of the surface surrounded by the surrounding line VII shown in FIG. FIG. 9A is an energy dispersive X-ray analyzer (EDX) in a scanning electron microscope (SEM) photograph showing a cross section of the vicinity of the surface of the electrode of Example 1 surrounded by the surrounding line VII shown in FIG. FIG. 9B shows the result of line analysis by an energy dispersive X-ray analyzer (EDX). 10A and 10B are scanning electron microscope (EDX) photographs showing the state of the conductive path layer formed on the surface of the YSZ particles in Example 1 before and after firing, respectively. FIG. 11 is an explanatory diagram schematically showing an electrode of Example 2. 12A is a scanning electron microscope (SEM) photograph showing a cross-section at the same position as the vicinity of the surface of the electrode of Comparative Example 1 surrounded by the surrounding line VII shown in FIG. It is explanatory drawing which shows the line analysis position by a type | mold X-ray analyzer (EDX), FIG.12 (B) is the result of the line analysis by an energy dispersive X-ray analyzer (EDX). FIGS. 13A and 13B are scanning electron microscope (EDX) photographs showing the state of the conductive path layer formed on the surface of the YSZ particles in Comparative Example 1 before and after firing, respectively. FIG. 14 is an explanatory view schematically showing an electrode of Comparative Example 2.

  Hereinafter, a solid oxide fuel cell electrode, a method of manufacturing the same, and a solid oxide fuel cell according to an embodiment of the present invention will be described in detail.

(First embodiment)
First, the electrode for a solid oxide fuel cell according to the first embodiment will be described in detail.
The electrode for a solid oxide fuel cell of the present embodiment includes an electrode layer and a current collector, and includes a conductive path layer and a predetermined intermediate layer.
The electrode layer is disposed in contact with the solid electrolyte layer, and the current collector is disposed in contact with the side of the electrode layer on which the solid electrolyte layer is disposed and the opposite side across the electrode layer.
In addition, the conductive path layer is disposed on at least a part of the surface of the electrode layer on the side where the current collector is disposed, and has a conductivity equivalent to the conductivity of the electrode layer and the conductivity of the electrode layer. It is composed of a plurality of conductive path layer material particles made of at least one conductive path layer material of a material having high conductivity, and has a structure in which the conductive path layer material particles are joined to each other.
Further, the intermediate layer is disposed between the electrode layer and the conductive path layer, and is composed of an electrode layer material forming the electrode layer and a conductive path layer material, and the distance from the conductive path layer in the thickness direction of the intermediate layer is It has a composition gradient structure in which the content of the conductive path layer material increases as it approaches.

By comprising an intermediate layer having a composition gradient structure that is composed of an electrode layer material and a conductive path layer material, and the content ratio of the conductive path layer material increases as the distance from the conductive path layer approaches in the thickness direction of the intermediate layer, The change in thermal expansion can be made gradual, and peeling of the conductive path layer is suppressed or prevented.
Further, the conductive path is composed of a plurality of conductive path layer material particles composed of at least one conductive path layer material of a material having conductivity equivalent to that of the electrode layer and a material having conductivity higher than that of the electrode layer. By providing a conductive path layer having a structure in which layer material particles are joined together, a sufficient conductive path is formed, and the conductivity is improved.
In other words, by adopting such a configuration, a solid oxide fuel cell electrode having a conductive path layer that is difficult to peel off and having excellent conductivity is obtained. Further, when such an electrode for a solid oxide fuel cell is applied to a solid oxide fuel cell, cell output can be improved.

Here, in the present invention, the “electrode layer material for forming the electrode layer” means a material for forming the electrode layer itself. For example, when the electrode layer is made of lanthanum strontium cobalt ferrite (La _1-x Sr _x Co _1-y Fe _y O ₃ : LSCF), the electrode layer material is only lanthanum strontium cobalt ferrite (La _1-x Sr _x Co _1-y Fe _y O 3: a LSCF), lanthanum strontium cobalt ferrite _{(La 1-x Sr x Co} 1-y Fe y O 3: LSCF) lanthanum oxide and strontium oxide constituting the cobalt oxide It does not mean iron oxide or the like. However, when the electrode layer is made of cermet of nickel (Ni) and yttria stabilized zirconia (YSZ), the electrode layer material is nickel (Ni) and yttria stabilized zirconia (YSZ). This interpretation is the same for the conductive path layer material.

  Hereinafter, each configuration will be described in more detail.

  Examples of the electrode layer include one or both of an air electrode layer and a fuel electrode layer disposed in contact with the solid electrolyte layer. The electrode layer preferably has a structure in which a plurality of ribs are provided on the current collector side.

Further, as the solid electrolyte layer, a layer having gas impermeability and a capability of passing oxide ions without passing electrons can be suitably used. As a constituent material of the solid electrolyte layer, for example, yttria (Y ₂ O ₃ ), neodymium oxide (Nd ₂ O ₃ ), samaria (Sm ₂ O ₃ ), gadria (Gd ₂ O ₃ ), scandia (Sc ₂ O _3). ) Or the like can be applied as stabilized zirconia. In addition, ceria solid solutions such as samaria doped ceria (SDC), yttria doped ceria (YDC), gadria doped ceria (GDC), bismuth oxide (Bi ₂ O ₃ ), lanthanum strontium magnesium gallate (La _1-x Sr _{x Ga 1-y Mg y O 3} : LSMG) or the like may be applied.

Furthermore, examples of the electrode layer material include platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), nickel (Ni), cobalt (Co), silver (Ag), and gold (Au). , Metals such as beryllium (Be), carbon (C), silicon (Si), iron (Fe), iridium (Ir), cesium (Cs), rhenium (Re), copper (Cu), lanthanum strontium cobaltite (La) _1-x Sr _x CoO ₃ : LSC), lanthanum strontium cobalt ferrite (La _1-x Sr _x Co _1-y Fe _y O ₃ : LSCF), samarium strontium cobaltite (Sm _x Sr _1-x CoO ₃ : SSC) , lanthanum strontium manganite _{(La 1-x Sr x MnO} 3: LSM), lanthanum calcium manganite _{(La 1-x Ca x MnO} 3), praseodymium strontium manganite _{(Pr 1-x Sr x MnO} 3), lanthanum strontium manganese cobaltite _{((La 1-x Sr x} Mn 1-y Co y O 3), lanthanum strontium manganese chromate _{(La 1-x Sr x Mn} 1-y Cr y O 3), lanthanum calcium cobaltite _{((La 1-x Ca x} CoO 3), praseodymium cobaltite (PrCoO _3), lanthanum nickel bis chromite (LaNi _1-x Bi _x O ₃ ), indium tin oxide (In _{2 -z} Sn _z O ₃ ), indium zirconium oxide (In _1-x Zr _x O ₃ ), ruthenium oxide / zirconium oxide (RuO ₂ / ZrO ₂₎ ) And other oxides having a perovskite structure, such as silver ( g), gold (Au), beryllium (Be), carbon (C), silicon (Si), iron (Fe), platinum (Pt), iridium (Ir), cesium (Cs), rhenium (Re) or copper ( Cu) or alloys containing metals according to any combination thereof, silver (Ag) and copper (Cu), tin (Sn), tellurium (Te), beryllium (Be), magnesium (Mg), cobalt (Co) and An alloy containing at least one metal selected from the group consisting of niobium (Nb) can be given.

Specifically, an air electrode layer that is strong in an oxidizing atmosphere, permeates oxidant gas, has high electrical conductivity, and has a catalytic action to convert oxygen molecules into oxide ions can be suitably used. . Moreover, even if it consists of an electrode catalyst, it may consist of a cermet of an electrode catalyst and electrolyte material. For example, a metal such as silver (Ag) or platinum (Pt) may be used as the electrode catalyst, but lanthanum strontium cobaltite (La _1-x Sr _x CoO ₃ : LSC) or lanthanum strontium cobalt ferrite ( _{La 1-x Sr x Co 1} -y Fe y O 3: LSCF), samarium strontium cobaltite _{(Sm x Sr 1-x CoO} 3: SSC), lanthanum strontium manganite _{(La 1-x Sr x MnO} 3: LSM It is preferable to apply a perovskite oxide such as However, it is not limited to these, and conventionally known air electrode materials can be applied. In addition, these can be applied individually by 1 type or in combination of multiple types. Furthermore, examples of the electrolyte material include, but are not limited to, cerium oxide (CeO ₂ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), and lanthanum oxide (La ₂ O ₃ ). However, a mixture with various kinds of stabilized zirconia and oxides such as ceria solid solution described later can be suitably used.

  In addition, a fuel electrode layer that is strong in a reducing atmosphere, permeates fuel gas, has high electrical conductivity, and has a catalytic action to convert hydrogen molecules into protons can be suitably used. As a constituent material of the fuel electrode, for example, a metal such as nickel (Ni) may be applied alone, but a cermet mixed with an oxide ion conductor typified by yttria stabilized zirconia (YSZ) is used. It is preferable to apply, thereby increasing the reaction area and improving the electrode performance. At this time, a ceria solid solution such as samaria doped ceria (SDC) or gadria doped ceria (GDC) can be applied instead of yttria stabilized zirconia (YSZ).

  Examples of the current collector include those formed from current collecting base materials such as heat-resistant alloys, corrosion-resistant alloys, corrosion-resistant steels, and stainless steels (SUS) containing nickel (Ni) and chromium (Cr). However, the present invention is not limited to these, and a current collector made of a conventionally known material applied to a solid oxide fuel cell can be applied. The current collector may have, for example, a structure provided on each rib provided on the electrode layer described above.

  Furthermore, as the conductive path layer, a plurality of conductive path layer materials comprising at least one conductive path layer material of a material having conductivity equivalent to the conductivity of the electrode layer and a material having conductivity higher than that of the electrode layer If it has a structure which consists of particle | grains and the electroconductive path layer material particle | grains were joined, it will not specifically limit. In addition, what is necessary is just to select a conductive path layer material suitably according to the electrode layer material which forms an air electrode layer and a fuel electrode layer.

  The intermediate layer is composed of an electrode layer material forming the electrode layer and a conductive path layer material, and the content ratio of the conductive path layer material increases as the distance from the conductive path layer decreases in the thickness direction of the intermediate layer. There is no particular limitation as long as it has a composition gradient structure. As described above, the conductive path layer material may be appropriately selected according to the electrode layer material forming the air electrode layer or the fuel electrode layer. The intermediate layer having such a composition gradient structure can be formed by using an injection processing technique such as an aerosol deposition method, which will be described later, while realizing cost reduction with a simple process.

  Furthermore, in this embodiment, it is preferable that the intermediate layer does not contain a composite material containing at least one component element constituting the electrode layer material and at least one component element constituting the conductive path layer material. . This is because the composite material as described above usually has poor conductivity. In addition, when an intermediate layer is formed using an injection processing technique such as an aerosol deposition method described later, a composite material containing a component element constituting the electrode layer material and a component element constituting the conductive path layer material is not formed. It was confirmed.

  Furthermore, in this embodiment, it is preferable that the thickness of the intermediate layer is 0.1 to 2 μm. Thus, by making the thickness of the intermediate layer very thin, it is possible to suppress a decrease in conductivity between the electrode layer and the conductive path layer. In addition, the intermediate layer having the above-described composition gradient structure having such a thickness achieves cost reduction with a simple process by using an injection processing technique such as an aerosol deposition method described later. Can be created.

(Second Embodiment)
Next, the solid oxide fuel cell according to the second embodiment will be described in detail.
The solid oxide fuel cell of the present embodiment has a solid electrolyte layer and the solid oxide fuel cell electrode according to the first embodiment described above. In the solid oxide fuel cell of the present invention, either the air electrode or the fuel electrode may be the electrode for the solid oxide fuel cell according to the first embodiment described above. Both of the fuel electrodes may be the solid oxide fuel cell electrode according to the first embodiment described above.
With such a configuration, the output of the solid oxide fuel cell is improved. In particular, high output can be stably obtained even under high temperature conditions.

(Third embodiment)
Next, a manufacturing method of the solid oxide fuel cell electrode according to the third embodiment will be described in detail. In addition, the manufacturing method of the electrode for solid oxide fuel cells of this embodiment is one Embodiment of the manufacturing method of the electrode for solid oxide fuel cells which concerns on 1st Embodiment mentioned above. Therefore, the electrode for a solid oxide fuel cell of the present invention is not necessarily limited to that manufactured by such a manufacturing method.
The manufacturing method of the electrode for the solid oxide fuel cell according to the present embodiment provides the electrode on at least a part of the surface of the electrode layer when manufacturing the electrode for the solid oxide fuel cell according to the first embodiment described above. The intermediate layer and the conductive path are made to collide with conductive path layer material particles made of at least one conductive path layer material of a material having conductivity equivalent to the conductivity of the layer and a material having conductivity higher than that of the electrode layer. It is a manufacturing method which forms a layer.

  Thus, the above-described predetermined intermediate layer and the predetermined conductive path layer can be formed by a simple process of causing the predetermined conductive path layer material particles to collide with the electrode layer, and the first embodiment described above. The manufacturing cost at the time of manufacturing the electrode for solid oxide fuel cells which concerns on this can be reduced more.

Specifically, conductive path layer material particles made of a conductive path layer material are applied to the electrode layer using an injection processing technique such as an aerosol deposition method, a powder jet deposition method, a warm spray method, a thermal spray method, or a cold spray method. By causing the collision, an intermediate layer and a conductive path layer can be formed on the electrode layer. More specifically, submicron-sized powdery conductive path layer material particles are flown at an optimum flow rate (for example, 300 to 800 m / s) with a carrier gas such as helium (He) gas or nitrogen (N ₂ ) gas. The electrode layer is ground by the particles, and a part of the kinetic energy of the particles is instantaneously converted into heat, so that the electrode layer material and the conductive path layer material An intermediate layer is formed, and the conductive path layer is subsequently formed by impacting the conductive path layer material particles.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
First, a zirconium oxide (YSZ) plate stabilized with yttrium oxide as a solid electrolyte layer, nickel (Ni) and YSZ as fuel electrode layer materials, and a stainless wire as a current collector were prepared.

  Next, a stainless steel wire serving as a current collector was placed on the solid electrolyte layer with a gap. The gap between the solid electrolyte layer and the stainless steel wire was at least equal to or higher than the wire diameter.

  Thereafter, these are put in a vacuum chamber, the inside of the chamber is decompressed, and after the pressure is reduced to a vacuum state, the spray nozzle of the gas deposition apparatus is moved to the upper part of the solid electrolyte layer and the current collector, Ni A porous electrode layer (fuel electrode layer) is formed in the gap between the solid electrolyte layer and the current collector by injecting the particles and YSZ particles on a high-speed helium (He) gas flow, thereby forming a conductive path layer. Thus, an electrode precursor used in this example in which the intermediate layer was not formed was obtained.

  FIG. 1 is a scanning electron microscope (SEM) photograph showing a cross section of the electrode precursor 1 ′ used in this example. As shown in FIG. 1, an electrode precursor 1 ′ includes an electrode layer (fuel electrode layer) 2 having a plurality of ribs 2a provided on the current collector 4 side, and a current collector 4 provided on each rib 2a. And have. Although not shown, a solid electrolyte layer exists on the opposite side of the electrode layer (fuel electrode layer) where the current collector is provided.

  Next, the obtained electrode precursor was put in a vacuum chamber, the pressure in the chamber was reduced to 1 Pa or less, and the oxidizing atmosphere was removed from the chamber.

  Next, the supersonic film-forming nozzle of the gas deposition apparatus is moved to the upper part of the electrode precursor, and Ni particles having a particle size of 0.8 to 1.0 μm are placed on a helium (He) gas flow of 800 m / s or more. By spraying, foreign substances present on the surface of the electrode precursor were removed.

  Further, by injecting Ni particles having a particle size of 0.8 to 1.0 μm on a helium (He) gas flow of 650 m / s, an intermediate layer and a conductive path layer are formed on the surface of the electrode precursor. Thus, an electrode of this example was obtained.

FIG. 2 is an explanatory view schematically showing a manufacturing method of the electrode 1 of this example. Moreover, FIG. 3 is explanatory drawing which shows typically the electrode 1 of this example.
As shown in FIG. 2, Ni particles p, which is an example of conductive path layer material particles, are collided from the supersonic film-forming nozzle N onto the surface of the electrode layer 2 of the electrode precursor 1 ′ and the rib 2a that is a part thereof. As a result, the intermediate layer 6 and the conductive path layer 8 were formed on the surface of the electrode precursor 1 ′, and the electrode 1 of this example as shown in FIG. 3 was obtained. 2 and 3, reference numeral 10 denotes a solid electrolyte layer, which is a YSZ plate.

In addition, about the electrode of this example, the surface and the cross section were observed with the scanning electron microscope (SEM). FIG. 4 is a scanning electron microscope (SEM) photograph showing a part of the surface of the electrode of this example. Further, FIG. 5 is a scanning electron microscope (SEM) photograph showing a cross section of the part surrounded by the surrounding line V shown in FIG. 4 of the electrode of this example. Further, FIG. 6 is a scanning electron microscope (SEM) photograph showing a cross section in the vicinity of the surface surrounded by the surrounding line VI shown in FIG. 5 of the electrode of this example.
As shown in FIG. 4, the electrode of this example is formed with a conductive path layer 8 made of Ni particles, which are conductive path layer material particles, and having a structure in which a plurality of Ni particles are joined to each other. I understand that. Further, as shown in FIG. 5, in the electrode of this example, Ni particles, which are conductive path layer material particles, hardly penetrate into the electrode layer 2, and the conductive path layer 8 is formed on the surface of the electrode layer 2. You can see that. Furthermore, as shown in FIG. 6, it can be seen that the electrode of this example has a conductive path layer 8 formed on the surface of electrode layer material particles (YSZ particles) 2A, which is an example of the constituent material of the electrode layer. .

FIG. 7 is an explanatory view schematically showing a cross section in the vicinity of the surface of the electrode of this example surrounded by the encircling line VII shown in FIG.
As shown in FIG. 7, the electrode of this example is composed of Ni particles, which are conductive path layer material particles, on the surface of electrode layer material particles (YSZ particles) 2A, which is an example of the constituent material of the electrode layer 2, on the surface thereof. A conductive path layer 8 having a structure in which a plurality of Ni particles are bonded to each other is formed, and between the electrode layer 2 and the conductive path layer 8, YSZ particles 2A, which are examples of electrode layer material particles, and the conductive path layer An intermediate layer 6 made of Ni particles 8A as material particles is formed.

  In addition, the cross section of the vicinity of the surface surrounded by the surrounding line VII shown in FIG. 6 of the electrode of this example is observed with a scanning electron microscope (SEM), and mapping element analysis is performed with an energy dispersive X-ray analyzer (EDX). Went. FIG. 8A shows the result of elemental analysis of zirconium (Zr) mapping by the energy dispersive X-ray analyzer (EDX) in the cross section of the vicinity of the surface surrounded by the surrounding line VII shown in FIG. 6 of the electrode of this example. is there. In FIG. 8A, the result of the elemental mapping of zirconium (Zr) is shown, but not only zirconium (Zr) is included. It was confirmed by other detailed component analysis that the electrode layer material particles (YSZ particles) 2A, which is an example of the constituent material of the electrode layer, were included. FIG. 8B shows the mapping elemental analysis of nickel (Ni) by the energy dispersive X-ray analyzer (EDX) in the cross-section of the vicinity of the surface surrounded by the surrounding line VII shown in FIG. 6 of the electrode of this example. It is a result. Note that FIG. 8C is a scanning electron microscope (SEM) photograph showing a cross section of the vicinity of the surface surrounded by the surrounding line VII shown in FIG. 6 of the electrode of this example.

  As shown in FIG. 8, in the electrode of this example, a conductive path layer made of Ni particles as conductive path layer material particles is formed on the surface layer of YSZ particles as a constituent material of the electrode layer. It can be seen that an intermediate layer made of YSZ as the electrode layer material and Ni as the conductive path layer material is formed between the particles and the conductive path layer. Moreover, the thickness of the intermediate layer is about 0.1 μm, and it can be confirmed that it is very thin. Such a thin intermediate layer does not hinder the conductivity between the electrode layer and the conductive path layer. In addition, when producing an intermediate | middle layer by the printing method using two types of materials which comprise an intermediate | middle layer, it is difficult to produce a thin intermediate | middle layer below 2 micrometers. And the thick intermediate | middle layer produced by the printing method may become a resistance factor which inhibits the electroconductivity between an electrode layer and a conductive path layer.

  Further, the cross section of the surface portion of the electrode surrounded by the enveloping line VII shown in FIG. 6 is observed with a scanning electron microscope (SEM), and mapping element analysis is performed with an energy dispersive X-ray analyzer (EDX). Went. FIG. 9A is a scanning electron microscope (SEM) photograph showing a cross section of the vicinity of the surface surrounded by the surrounding line VII shown in FIG. 6 of the electrode of this example, which is obtained by an energy dispersive X-ray analyzer (EDX). It is explanatory drawing which shows a line analysis position. FIG. 9B shows the result of line analysis using an energy dispersive X-ray analyzer (EDX).

  As shown in FIG. 9, in the electrode of this example, the intermediate layer has a composition gradient structure in which the content ratio of the conductive path layer material increases as the distance from the conductive path layer approaches a → b in the thickness direction. It turns out that it has.

[Performance evaluation]
(Peeling suppression performance test)
The electrode of this example was subjected to a peeling suppression performance test. Specifically, the state of the conductive path layer before and after firing at 950 ° C. for 10 hours was observed with a scanning electron microscope (EDX). FIGS. 10A and 10B are scanning electron microscope (EDX) photographs showing the state of the conductive path layer formed on the surface of the YSZ particles before and after firing, respectively.

  As shown in FIG. 10, in the electrode of this example, even after firing, peeling of the conductive path layer 8 from the electrode layer material particles (YSZ particles) 2A, which is an example of the constituent material of the electrode layer, was not confirmed. .

(Conductive performance test)
The electrode of this example was subjected to a conductive performance test in which current and voltage were applied to the current collector and the lower end of the electrode layer on the solid electrolyte layer side in a reducing atmosphere at 750 ° C. Specifically, the voltage difference was fixed at 4 V, and the resistance change with respect to the current change at a constant voltage load was measured. The contact resistance (ASR) was calculated from the obtained resistance value.
The resistance value in the electrode of this example was 2.82 × 10 ⁻⁴ Ωcm ² .

(Example 2)
The same operation as in Example 1 was repeated except that a gas reservoir was provided by halving the gas flow rate of Ni particles so that Ni particles could not be deposited on the electrode surface farthest from the supersonic deposition nozzle. Thus, the intermediate layer and the conductive path layer were formed only on the surfaces of the ribs of the electrode layer to obtain the electrode of this example. FIG. 11 is an explanatory view schematically showing an electrode of this example. As shown in FIG. 11, the electrode 1 </ b> A of this example includes an electrode layer 2 and a current collector 4, and an intermediate layer 6 and a conductive path layer 8 are formed only on the surface of the rib 2 a of the electrode layer 2. is there. After the film formation, the increase in the cell weight was measured and the Ni film formation weight was calculated. As a result, the amount of Ni particle formation per unit electrode area was almost the same as in Example 1. For this reason, it was possible to compare the difference in film formation site of the conductive path layer.

[Performance evaluation]
(Conductive performance test)
For the electrode of this example, the same operation as in Example 1 was repeated to calculate the contact resistance (ASR).
The resistance value in the electrode of this example was 3.05 × 10 ⁻⁴ Ωcm ² .

(Comparative Example 1)
First, a zirconium oxide (YSZ) plate stabilized with yttrium oxide as a solid electrolyte layer, a fuel electrode layer material slurry containing nickel (Ni) and YSZ as a fuel electrode layer material, and nickel as a conductive path layer material A conductive path layer material slurry containing (Ni) and a stainless wire as a current collector were prepared.

  Next, an electrode layer and a conductive path layer are formed on the solid electrolyte layer by a printing method using the fuel electrode layer material slurry and the conductive path layer material slurry, and a current collector is installed on the conductive path layer. Electrode was obtained.

  Further, the cross section of the electrode in this example at the same position as the surface vicinity surrounded by the enveloping line VII shown in FIG. 6 is observed with a scanning electron microscope (SEM) and an energy dispersive X-ray analyzer (EDX). Mapping elemental analysis was performed. FIG. 12A is an energy dispersive X-ray analyzer in a scanning electron microscope (SEM) photograph showing a cross-section at the same position as the surface vicinity portion surrounded by the enveloping line VII shown in FIG. 6 of the electrode of this example. It is explanatory drawing which shows the line analysis position by (EDX). FIG. 12B shows the results of line analysis using an energy dispersive X-ray analyzer (EDX).

  As shown in FIG. 12, in the electrode of this example, the intermediate layer itself could not be confirmed.

[Performance evaluation]
(Peeling suppression performance test)
About the electrode of this example, the same operation as Example 1 was repeated and the peeling suppression performance test was done. FIGS. 13A and 13B are scanning electron microscope (EDX) photographs showing the state of the conductive path layer formed on the surface of the YSZ particles before and after firing, respectively.

  As shown in FIG. 13, in the electrode of this example, peeling of the conductive path layer 8 was confirmed from electrode layer material particles (YSZ particles) 2A, which is an example of the constituent material of the electrode layer, after firing.

(Comparative Example 2)
First, a zirconium oxide (YSZ) plate stabilized with yttrium oxide as a solid electrolyte layer, a fuel electrode layer material slurry containing nickel (Ni) and YSZ as a fuel electrode layer material, and nickel as a conductive path layer material A conductive path layer material slurry containing (Ni) and YSZ and a stainless wire as a current collector were prepared.

  Next, an electrode layer is formed on the solid electrolyte layer by a printing method using a fuel electrode layer material slurry, and a conductive path layer is formed by a printing method using a conductive path layer material slurry at a portion corresponding to the rib portion of Example 1. And a current collector was placed on the conductive path layer to obtain an electrode of this example. FIG. 14 is an explanatory view schematically showing an electrode of this example. As shown in FIG. 14, the electrode 1 of this example includes an electrode layer 2 and a current collector 4, and includes a fuel electrode material 2 </ b> A and a conductive path material 8 </ b> A in a portion corresponding to the rib 2 a of the first embodiment. A conductive path layer 8 is formed. In addition, the content of nickel (Ni) in the conductive path layer of this example is the content of nickel (Ni) in the conductive path layer of Example 1 with respect to the original content of nickel (Ni) in the electrode layer. The amount added.

[Performance evaluation]
(Conductive performance test)
For the electrode of this example, the same operation as in Example 1 was repeated to calculate the contact resistance (ASR).
The resistance value in the electrode of this example was 3.38 × 10 ⁻⁴ Ωcm ² .

  It can be seen that the resistance values of Examples 1 and 2 belonging to the scope of the present invention are lower than the resistance value of Comparative Example 2 outside the present invention. This indicates that the resistance of the entire electrode from the current collector to the electrode layer is reduced by the current flowing preferentially through the conductive path layer. Further, in the electrodes of Examples 1 and 2, peeling of the conductive path layer could not be confirmed after the peeling suppression performance test, but in the electrode of Comparative Example 1, peeling of the conductive path layer was confirmed after the peeling suppression performance test. It was. In the electrodes of Examples 1 and 2, the peeling of the conductive path layer was suppressed after the peeling suppression performance test because the difference in thermal expansion between the electrode layer and the conductive path layer was alleviated by the composition gradient structure of the intermediate layer. Conceivable.

  As mentioned above, although this invention was demonstrated with some embodiment and an Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.

  For example, the configuration described in each embodiment and each example described above is not limited to each embodiment or each example. For example, the configuration of the electrode layer, the intermediate layer, and the conductive path layer in each embodiment is the same. The configuration of each embodiment or each example can be changed to a combination other than each embodiment or each example described above.

  Further, for example, in the above-described embodiments, the fuel electrode layer has been illustrated and described as the electrode layer on which the intermediate layer and the conductive path layer are provided. A layer can also be selected, and although not shown, such a case is also included in the scope of the present invention.

1, 1A, 1B Electrode 1 'Electrode precursor 2 Electrode layer 2A Electrode layer material particle 2a Rib 4 Current collector 6 Intermediate layer 8 Conductive pass layer 8A Conductive pass layer material particle 10 Solid electrolyte layer N Supersonic film-forming nozzle p Conductive Pass layer material particles

Claims (7)

An electrode layer disposed in contact with the solid electrolyte layer;
A side of the electrode layer on which the solid electrolyte layer is disposed and a current collector disposed on and in contact with the electrode layer on the opposite side of the electrode layer ;
A material having a conductivity equivalent to the conductivity of the electrode layer and a conductivity higher than the conductivity of the electrode layer, disposed on at least a part of the surface of the electrode layer on the side where the current collector is disposed A conductive path layer comprising a plurality of conductive path layer material particles made of at least one of the conductive path layer materials, and having a structure in which the conductive path layer material particles are joined together;
An intermediate layer that is disposed between the electrode layer and the conductive path layer and includes the electrode layer material forming the electrode layer and the conductive path layer material;
The solid oxide fuel cell, wherein the intermediate layer has a composition gradient structure in which the content ratio of the conductive path layer material increases as the distance from the conductive path layer decreases in the thickness direction of the intermediate layer Electrode. An electrode layer disposed in contact with the solid electrolyte layer;
A side of the electrode layer on which the solid electrolyte layer is disposed and a current collector disposed on and in contact with the opposite side of the electrode layer;
A material having a conductivity equivalent to the conductivity of the electrode layer and a conductivity higher than the conductivity of the electrode layer, disposed on at least a part of the surface of the electrode layer on the side where the current collector is disposed A conductive path layer comprising a plurality of conductive path layer material particles made of at least one of the conductive path layer materials, and having a structure in which the conductive path layer material particles are joined together;
An intermediate layer that is disposed between the electrode layer and the conductive path layer and includes the electrode layer material forming the electrode layer and the conductive path layer material;
The intermediate layer has a composition gradient structure in which the content ratio of the conductive path layer material increases as the distance from the conductive path layer decreases in the thickness direction of the intermediate layer,
The intermediate layer is a solid body you characterized by not containing a composite material containing at least one component element constituting at least one component element and the conductive path layer material forming the electrode layer material Oxide fuel cell electrode. An electrode layer disposed in contact with the solid electrolyte layer;
A side of the electrode layer on which the solid electrolyte layer is disposed and a current collector disposed on and in contact with the opposite side of the electrode layer;
A material having a conductivity equivalent to the conductivity of the electrode layer and a conductivity higher than the conductivity of the electrode layer, disposed on at least a part of the surface of the electrode layer on the side where the current collector is disposed A conductive path layer comprising a plurality of conductive path layer material particles made of at least one of the conductive path layer materials, and having a structure in which the conductive path layer material particles are joined together;
An intermediate layer that is disposed between the electrode layer and the conductive path layer and includes the electrode layer material forming the electrode layer and the conductive path layer material;
The intermediate layer has a composition gradient structure in which the content ratio of the conductive path layer material increases as the distance from the conductive path layer decreases in the thickness direction of the intermediate layer,
The thickness of the intermediate layer is a solid body oxide fuel cell electrode you being a 0.1-2 .mu.m. 2. The intermediate layer does not include a composite material containing at least one component element constituting the electrode layer material and at least one component element constituting the conductive path layer material. Or an electrode for a solid oxide fuel cell as described in 3; 3. The solid oxide fuel cell electrode according to claim 1, wherein the intermediate layer has a thickness of 0.1 to 2 [mu] m. A solid oxide fuel cell comprising the electrode for a solid oxide fuel cell according to any one of claims 1 to 5 and a solid electrolyte layer. In producing the electrode for a solid oxide fuel cell according to any one of claims 1 to 5 ,
A conductive path comprising at least one conductive path layer material of a material having conductivity equivalent to that of the electrode layer and a material having conductivity higher than that of the electrode layer on at least a part of the surface of the electrode layer A method for producing an electrode for a solid oxide fuel cell, comprising forming an intermediate layer and a conductive path layer by colliding layer material particles.

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