JP2009054520A - Electrode-electrolyte membrane assembly, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode-electrolyte membrane assembly and a manufacturing method thereof, capable of improving an electric conductivity of an electrolyte membrane on an electrode. <P>SOLUTION: The electrode-electrolyte membrane assembly (50) includes an electrode (10), a first electrolyte membrane (30) arranged on the electrode, and a second electrolyte membrane (40) arranged on the first electrolyte membrane. A grain boundary resistance of an electrolyte forming the first electrolyte membrane is smaller than a grain boundary resistance of the electrolyte forming the second electrolyte membrane. The electrode-electrolyte membrane assembly can improve the electric conductivity of the electrolyte membrane on the electrode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrode-electrolyte membrane assembly and a method for producing the same.

  A fuel cell is a device that generally obtains electric energy using hydrogen and oxygen as fuel. Since this fuel cell is excellent in terms of the environment and can realize high energy efficiency, it has been widely developed as a future energy supply system.

  In order to improve power generation efficiency, it is conceivable to reduce the membrane resistance by reducing the thickness of the electrolyte membrane. For example, it is conceivable to reduce the thickness of the electrolyte membrane by forming an electrolyte membrane on the electrode by a vapor deposition method. Patent Document 1 discloses a technique for forming an electrolyte membrane on a hydrogen separation membrane that functions as an anode.

JP 2005-251550 A

  The electrolyte membrane formed on the electrode often has a polycrystalline structure. The conductivity of the polycrystalline electrolyte membrane is smaller than that of the single crystal electrolyte membrane (hereinafter referred to as theoretical conductivity). This is because, generally, a crystal grain boundary is formed in the polycrystal, and the conductivity of the crystal grain boundary is lower than the conductivity in the crystal grain. In this case, power generation efficiency may be reduced.

  An object of this invention is to provide the electrode-electrolyte membrane assembly which can improve the electrical conductivity of the electrolyte membrane on an electrode, and its manufacturing method.

  An electrode-electrolyte membrane assembly according to the present invention includes an electrode, a first electrolyte membrane provided on the electrode, and a second electrolyte membrane provided on the first electrolyte membrane, and the first electrolyte membrane is provided with the first electrolyte membrane. The grain boundary resistance of the constituent electrolyte is smaller than the grain boundary resistance of the electrolyte constituting the second electrolyte membrane. According to the electrode-electrolyte membrane assembly according to the present invention, since the grain boundary resistance of the electrolyte constituting the first electrolyte membrane is smaller than the grain boundary resistance of the electrolyte constituting the second electrolyte membrane, the electrolyte membrane The grain boundary resistance in the vicinity of the electrodes can be reduced. As a result, the conductivity of the electrolyte membrane can be improved as compared with the case where the entire electrolyte membrane is composed of the second electrolyte membrane.

  In the above configuration, the electrolyte constituting the first electrolyte membrane may have a higher sinterability than the electrolyte constituting the second electrolyte membrane. According to this configuration, the crystal grain size in the vicinity of the interface on the electrode side of the first electrolyte membrane tends to be large. Thereby, the ratio of the grain boundary in the first electrolyte membrane can be reduced. As a result, the conductivity of the electrolyte membrane can be improved.

  In the above configuration, the electrolyte that configures the first electrolyte membrane may be one that uses the electrolyte that configures the second electrolyte membrane as a base material and includes a sintering aid. According to this structure, the electrolyte which comprises a 1st electrolyte membrane has high sinterability compared with the electrolyte which comprises a 2nd electrolyte membrane. Moreover, since the electrolyte which comprises a 1st electrolyte membrane uses the electrolyte which comprises a 2nd electrolyte membrane as a base material, the structure of a 1st electrolyte membrane and the structure of a 2nd electrolyte membrane approximate. Thereby, the adhesion strength between the first electrolyte membrane and the second electrolyte membrane is improved. As a result, peeling between the first electrolyte membrane and the second electrolyte membrane is suppressed.

  In the above configuration, the lattice constant of the electrolyte constituting the first electrolyte membrane may be closer to the lattice constant of the electrode than the lattice constant of the electrolyte constituting the second electrolyte membrane. According to this configuration, the first electrolyte membrane is closer to the electrode structure than the second electrolyte membrane. Therefore, generation of fine crystals in the first electrolyte membrane is suppressed. In this case, the crystal grain size in the first electrolyte membrane tends to be large. Thereby, the ratio of the grain boundary in the first electrolyte membrane can be reduced. As a result, the conductivity of the electrolyte membrane can be improved. Further, since the lattice constant of the electrolyte constituting the first electrolyte membrane is closer to the lattice constant of the electrode compared to the lattice constant of the electrolyte constituting the second electrolyte membrane, the bond strength between the first electrolyte membrane and the electrode is Compared to the case where the second electrolyte membrane is provided directly on the electrode, the improvement is achieved. Thereby, peeling between the electrode and the electrolyte membrane can be suppressed.

  In the above configuration, the electrode may be a hydrogen separation membrane having hydrogen permeability, and the first electrolyte membrane and the second electrolyte membrane may be made of an electrolyte having proton conductivity.

  A method for producing an electrode-electrolyte membrane assembly according to the present invention includes a step of forming a first electrolyte membrane on an electrode and a step of forming a second electrolyte membrane on the first electrolyte membrane, The grain boundary resistance of the electrolyte constituting one electrolyte membrane is small compared to the grain boundary resistance of the electrolyte constituting the second electrolyte membrane. According to the method for producing an electrode-electrolyte membrane assembly according to the present invention, the grain boundary resistance of the electrolyte constituting the first electrolyte membrane is smaller than the grain boundary resistance of the electrolyte constituting the second electrolyte membrane. The grain boundary resistance in the vicinity of the electrode of the electrolyte membrane can be reduced. As a result, the conductivity of the electrolyte membrane can be improved as compared with the case where the entire electrolyte membrane is composed of the second electrolyte membrane.

  In the said manufacturing method, the electrolyte which comprises a 1st electrolyte membrane may have high sinterability compared with the electrolyte which comprises a 2nd electrolyte membrane. According to this manufacturing method, the crystal grain size in the vicinity of the interface on the electrode side of the first electrolyte membrane tends to be large. Thereby, the ratio of the grain boundary in the first electrolyte membrane can be reduced. As a result, the conductivity of the electrolyte membrane can be improved.

  In the manufacturing method described above, the electrolyte constituting the first electrolyte membrane may be one that uses the electrolyte constituting the second electrolyte membrane as a base material and includes a sintering aid. According to this manufacturing method, the electrolyte constituting the first electrolyte membrane has higher sinterability than the electrolyte constituting the second electrolyte membrane. Moreover, since the electrolyte which comprises a 1st electrolyte membrane uses the electrolyte which comprises a 2nd electrolyte membrane as a base material, the structure of a 1st electrolyte membrane and the structure of a 2nd electrolyte membrane approximate. Thereby, the adhesion strength between the first electrolyte membrane and the second electrolyte membrane is improved. As a result, peeling between the first electrolyte membrane and the second electrolyte membrane is suppressed.

  In the above manufacturing method, the lattice constant of the electrolyte constituting the first electrolyte membrane may be closer to the lattice constant of the electrode as compared with the lattice constant of the electrolyte constituting the second electrolyte membrane. According to this manufacturing method, the first electrolyte membrane is closer to the structure of the electrode than the second electrolyte membrane. Therefore, generation of fine crystals in the first electrolyte membrane is suppressed. In this case, the crystal grain size in the first electrolyte membrane tends to be large. Thereby, the ratio of the grain boundary in the first electrolyte membrane can be reduced. As a result, the conductivity of the electrolyte membrane can be improved. Further, since the lattice constant of the electrolyte constituting the first electrolyte membrane is closer to the lattice constant of the electrode compared to the lattice constant of the electrolyte constituting the second electrolyte membrane, the bond strength between the first electrolyte membrane and the electrode is Compared to the case where the second electrolyte membrane is formed directly on the electrode, this is improved. Thereby, peeling between the electrode and the electrolyte membrane can be suppressed.

  In the manufacturing method, the electrode may be a hydrogen permeable membrane having hydrogen permeability, and the first electrolyte membrane and the second electrolyte membrane may be made of an electrolyte having proton conductivity.

  ADVANTAGE OF THE INVENTION According to this invention, the electrode-electrolyte membrane assembly which can improve the electrical conductivity of the electrolyte membrane on an electrode, and its manufacturing method can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 is a schematic cross-sectional view showing an electrode-electrolyte membrane assembly 50 according to a first embodiment of the present invention. As shown in FIG. 1, the electrode-electrolyte membrane assembly 50 has a structure in which an electrolyte membrane 20 is provided on an electrode 10. As the electrode 10, a material that functions as an anode or a cathode when the electrode-electrolyte membrane assembly 50 is used in a fuel cell can be used. In this embodiment, a hydrogen separation membrane made of a dense hydrogen permeable metal can be used as the electrode 10. In this embodiment, the electrode 10 has a dense structure to such an extent that hydrogen permeates in the form of hydrogen atoms and / or protons. The material constituting the electrode 10 is not particularly limited as long as it is dense and has hydrogen permeability and conductivity. Note that the hydrogen separation membrane functions as an anode.

  Specifically, for example, a metal such as Pd (palladium), V (vanadium), Ta (tantalum), Nb (niobium), or an alloy thereof can be used as the electrode 10. Moreover, you may use as the electrode 10 what formed films | membranes, such as palladium and palladium alloy which have hydrogen dissociation ability, on both surfaces of these hydrogen permeable metal layers. The electrode 10 may be a self-supporting film or may be supported by a porous base metal plate. Although the thickness of the electrode 10 is not specifically limited, For example, it is about several tens of micrometers.

  The electrolyte membrane 20 includes a first electrolyte membrane 30 and a second electrolyte membrane 40. The first electrolyte membrane 30 is disposed on the electrode 10 side and is made of an electrolyte having a smaller grain boundary resistance than the second electrolyte membrane 40. Here, the grain boundary resistance refers to the conduction resistance of charged particles at the crystal grain boundary. The charged particle according to the present embodiment is a proton.

When using _BaZr 0.8 _Y 0.2 _{O 3} as the second membrane 40 can be in a first membrane 30 using, for example, _SrZr 0.8 _In 0.2 _{O 3.}

  Here, a phenomenon in which the conductivity of the electrolyte membrane having a polycrystalline structure becomes smaller than the theoretical value will be described in detail. When the electrolyte membrane has a polycrystalline structure, the charged particles conduct both at the grain boundaries and within the grains of the electrolyte membrane. Therefore, when the electrolyte membrane has a polycrystalline structure, the conductivity of the electrolyte membrane is determined based on the sum (overall resistance) of the grain boundary resistance and the intragranular resistance (conducting resistance of charged particles in the crystal grains). For example, if the total resistance is large, the conductivity is low, and if the total resistance is small, the conductivity is high.

  In general, since it is considered that a charged particle is less likely to conduct at a grain boundary than within a grain, the grain boundary resistance is considered to be larger than the intragranular resistance. Therefore, the higher the proportion occupied by the grain boundary of the electrolyte membrane, that is, the more fine crystal grains, the lower the conductivity of the electrolyte membrane. For this reason, the conductivity of the electrolyte membrane having a polycrystalline structure is considered to be smaller than the theoretical value.

  As in this embodiment, when there is a structural difference between the electrode 10 and the electrolyte membrane 20, the crystal grains of the electrolyte membrane 20 tend to be fine in the vicinity of the electrode 10. In this case, the grain boundary ratio increases in the vicinity of the electrode 10. However, the grain boundary resistance in the vicinity of the electrode 10 of the electrolyte membrane 20 can be reduced by disposing the first electrolyte membrane 30 having a low grain boundary resistance on the electrode 10 as in this embodiment. As a result, the conductivity of the electrolyte membrane 20 is higher than when the entire electrolyte membrane 20 is composed of the second electrolyte membrane 40. From the above, the power generation efficiency of the fuel cell using the electrode-electrolyte membrane assembly 50 according to the present embodiment is improved. In general, an electrolyte having a low intergranular resistance has a high intragranular resistance. Therefore, when the entire electrolyte membrane 20 is composed of the first electrolyte membrane 30, it is difficult to obtain high conductivity in the electrolyte membrane 20.

  In this embodiment, the electrode 10 is composed of a dense metal layer, but is not limited thereto. For example, the electrode 10 may be a porous body made of a material having anode activity such as Pt (platinum) or Ni (nickel). Also in this case, the effect of the present invention can be obtained because the crystal grains of the electrolyte membrane in the vicinity of the electrode 10 are easily miniaturized.

  However, when the electrode 10 is made of a dense hydrogen-permeable metal layer, the effect of the present invention is particularly great. The reason will be described below. When the electrode 10 is made of a dense hydrogen-permeable metal layer, the electrolyte membrane 20 can be thinned. This is because the electrolyte membrane 20 becomes dense without increasing the thickness of the electrolyte membrane 20. Since the membrane resistance decreases when the thickness of the electrolyte membrane 20 is small, the thickness of the electrolyte membrane 20 is preferably small in order to improve power generation efficiency. However, when the thickness of the electrolyte membrane 20 is small, the proportion of fine crystal grains in the electrolyte membrane 20 increases. Therefore, when the present invention is applied when the electrolyte membrane 20 is thinned, the effect of improving the conductivity of the electrolyte membrane 20 becomes particularly large.

  Next, a method for manufacturing the electrode-electrolyte membrane assembly 50 will be described. FIG. 2A and FIG. 2B are schematic cross-sectional views showing a method for manufacturing the electrode-electrolyte membrane assembly 50. First, as shown in FIG. 2A, a first electrolyte film 30 is formed on the electrode 10. As a film forming method, for example, a vapor phase film forming method such as CVD or PVD can be used. For example, when the film is formed by PVD, the electrode 10 is placed in a vacuum chamber (not shown) as a base material. Further, an oxide element constituting the first electrolyte membrane 30 is disposed in the vacuum chamber as a target (not shown). When energy is applied to the target by a pulse laser or the like, an electrolyte constituent element is released from the target. The released electrolyte constituent element is deposited on the electrode 10. Thereby, the first electrolyte membrane 30 is formed on the electrode 10.

  In addition, the crystal grains in the vicinity of the electrode 10 of the first electrolyte membrane 30 formed in FIG. This is because the first electrolyte membrane 30 having a structure different from that of the electrode 10 is formed on the electrode 10.

  Next, a second electrolyte membrane 40 is formed on the first electrolyte membrane 30 as shown in FIG. As a film forming method, for example, a vapor phase film forming method such as CVD or PVD can be used. The electrode-electrolyte membrane assembly 50 is manufactured by the above method.

  Note that the crystal grains in the vicinity of the first electrolyte film 30 of the second electrolyte film 40 formed in FIG. 2B are larger than those in the case where the second electrolyte film 40 is directly formed on the electrode 10. Become. This is because the second electrolyte membrane 40 having the same structure as the first electrolyte membrane 30 is formed on the first electrolyte membrane 30.

  According to the above manufacturing method, the crystal grains of the electrolyte membrane 20 tend to be fine in the vicinity of the electrode 10. In this case, the grain boundary ratio increases in the vicinity of the electrode 10. However, by forming the first electrolyte membrane 30 having a low grain boundary resistance on the electrode 10, the grain boundary resistance in the vicinity of the electrode 10 of the electrolyte membrane 20 can be reduced. As a result, the conductivity of the electrolyte membrane 20 is higher than when the entire electrolyte membrane 20 is composed of the second electrolyte membrane 40. From the above, the power generation efficiency of the fuel cell using the electrode-electrolyte membrane assembly 50 according to the present embodiment is improved.

  If the grain boundary resistance of the electrolyte constituting the first electrolyte membrane 30 is smaller than the grain boundary resistance of the electrolyte constituting the second electrolyte membrane 40, the electrode-electrolyte membrane assembly 50 is separated by hydrogen separation. It is not limited to a membrane-electrolyte membrane assembly. For example, the electrode-electrolyte membrane assembly 50 may be an electrode-electrolyte membrane assembly 50 used in a solid oxide fuel cell (SOFC) in which oxygen ions are conducted as charged particles. In this case, the electrode 10 functions as a cathode. Furthermore, an SOFC in which protons are conductive may be used as the charged particles. In this case, the electrode 10 functions as an anode.

(Modification 1)
In addition, as the electrolyte constituting the first electrolyte membrane 30, an electrolyte having higher sinterability than the electrolyte constituting the second electrolyte membrane 40 may be used. Here, high sinterability means that the sintering temperature is low. The sintering temperature refers to a temperature at which an oxide having a crystal structure without through holes is formed.

For example, when a hydrogen separation membrane is used as the electrode 10 and BaZr _0.8 Y _0.2 O ₃ is used as the electrolyte constituting the second electrolyte membrane 40, the electrolyte constituting the first electrolyte membrane 30 is as follows: BaZr _0.8 Ga _0.2 O ₃ , BaZr _0.8 Y _0.1 In _0.1 O _3, or the like can be used. The sintering temperature of BaZr _0.8 Y _0.2 O ₃ is 1750 ° C., whereas the sintering temperature of BaZr _0.8 Ga _0.2 O ₃ is 1600 ° C. to 1650 ° C., and BaZr _0.8 The sintering temperature of Y _0.1 In _0.1 O ₃ is 1650 ° C. Therefore, the electrolyte constituting the first electrolyte membrane 30 has higher sinterability than the electrolyte constituting the second electrolyte membrane 40.

  According to the electrode-electrolyte membrane assembly 50 according to the first modification, the crystal grain size in the vicinity of the interface on the electrode 10 side of the first electrolyte membrane 30 tends to be large. Thereby, the ratio of the grain boundary in the 1st electrolyte membrane 30 can be reduced. As a result, the conductivity of the electrolyte membrane 20 can be improved.

(Modification 2)
Further, as the electrolyte constituting the first electrolyte membrane 30, an electrolyte comprising the second electrolyte membrane 40 as a base material and containing a sintering aid may be used. For example, when a hydrogen separation membrane is used as the electrode 10 and BaZr _0.8 Y _0.2 O ₃ is used as the electrolyte constituting the second electrolyte membrane 40, the electrolyte constituting the first electrolyte membrane 30 is BaZr. _An oxide containing _0.8 Y _0.2 O ₃ as a base material and containing a sintering aid such as In ₂ O ₃ , Ga ₂ O ₃ , ZnO ₃ may be used.

  As a manufacturing method of the electrode-electrolyte membrane assembly 50 according to the second modification, the same method as the vapor deposition method shown in FIG. 2 can be used. For example, when the electrode-electrolyte membrane assembly 50 is formed by PVD, the electrode 10 is placed in a vacuum chamber as a base material. Moreover, two types of targets, ie, a constituent element of the electrolyte constituting the second electrolyte membrane 40 and a constituent element of the sintering aid, are prepared as targets, and these two kinds of targets are arranged in a vacuum chamber. When energy is applied to the target by a pulse laser or the like, the constituent element of the electrolyte is released from the target of the electrolyte, the constituent element of the sintering aid is released from the target of the sintering aid, and is deposited on the electrode 10. . Thereby, the first electrolyte membrane 30 is formed on the electrode 10. Next, the second electrolyte film 40 is formed on the first electrolyte film 30 by a vapor deposition method. By the above method, the electrode-electrolyte membrane assembly 50 according to Modification 2 is manufactured.

  As another method for forming the first electrolyte film 30 on the electrode 10, a thin sintering aid is formed on the electrode 10 by a vapor deposition method, and then the electrolyte is applied on the sintering aid. A method of forming a film by a vapor deposition method may be used. When an electrolyte is deposited on the sintering aid, the sintering aid diffuses into the electrolyte. Thereby, the first electrolyte membrane 30 containing the electrolyte as a base material and further containing a sintering aid can be formed on the electrode 10.

  Alternatively, as another method of forming the first electrolyte film 30 on the electrode 10, the electrolyte is formed on the electrode 10 by a vapor deposition method, and then a sintering aid is formed on the electrolyte by vapor deposition. Alternatively, a film forming method may be used. When the sintering aid is deposited on the electrolyte, the sintering aid diffuses into the electrolyte. Thereby, the first electrolyte membrane 30 containing the electrolyte as a base material and further containing a sintering aid can be formed on the electrode 10.

  According to the electrode-electrolyte membrane assembly 50 according to the second modification, since the electrolyte constituting the first electrolyte membrane 30 includes the sintering aid, the electrolyte constituting the first electrolyte membrane 30 is the second electrolyte. Compared to the electrolyte constituting the membrane 40, it has high sinterability. In this case, the crystal grain size in the vicinity of the interface on the electrode 10 side of the first electrolyte membrane 30 tends to be large. Thereby, the ratio of the grain boundary in the 1st electrolyte membrane 30 can be reduced. As a result, the conductivity of the electrolyte membrane 20 can be improved. In addition, since the electrolyte constituting the first electrolyte membrane 30 is based on the electrolyte constituting the second electrolyte membrane 40, the structure of the first electrolyte membrane 30 and the structure of the second electrolyte membrane 40 are approximated. Thereby, the adhesion strength between the first electrolyte membrane 30 and the second electrolyte membrane 40 is improved. As a result, peeling between the first electrolyte membrane 30 and the second electrolyte membrane 40 is suppressed.

(Modification 3)
Further, as the electrolyte constituting the first electrolyte membrane 30, an electrolyte whose lattice constant is closer to the lattice constant of the electrode 10 than the lattice constant of the electrolyte constituting the second electrolyte membrane 40 may be used. For example, when a hydrogen separation membrane made of Pd is used as the electrode 10 and BaZr _0.8 Y _0.2 O ₃ is used as the electrolyte constituting the second electrolyte membrane 40, the electrolyte constituting the first electrolyte membrane 30 is used. As SrTiO ₃ , Sr _0.79 Ba _0.21 TiO ₃ or the like can be used. Note that the lattice constant of Pd is 3.891Å, the lattice constant of BaZr _0.8 Y _0.2 O ₃ is 4.193Å, the lattice constant of SrTiO ₃ is 3.905Å, and Sr _0.79 Ba. The lattice constant of _0.21 TiO ₃ is 3.937 Å.

  The electrode-electrolyte membrane assembly 50 according to Modification 3 is manufactured by a vapor deposition method, similarly to the manufacturing method according to Example 1 shown in FIG. For example, the electrode-electrolyte membrane assembly 50 is manufactured by depositing the first electrolyte membrane 30 on the electrode 10 and then depositing the second electrolyte membrane 40 on the first electrolyte membrane 30.

  According to the electrode-electrolyte membrane assembly 50 according to the third modification, the lattice constant of the electrolyte constituting the first electrolyte membrane 30 is higher than the lattice constant of the electrolyte constituting the second electrolyte membrane 40. Since it is close to a constant, the first electrolyte membrane 30 is closer to the structure of the electrode 10 than the second electrolyte membrane 40. Therefore, the generation of fine crystals in the first electrolyte membrane 30 is suppressed. In this case, the crystal grain size in the first electrolyte membrane 30 tends to increase. Thereby, the ratio of the grain boundaries in the first electrolyte membrane 30 can be made. As a result, the conductivity of the electrolyte membrane 20 can be improved. Further, since the lattice constant of the electrolyte constituting the first electrolyte membrane 30 is closer to the lattice constant of the electrode 10 as compared with the lattice constant of the electrolyte constituting the second electrolyte membrane 40, the first electrolyte membrane 30 and the electrode 10 The bond strength is improved as compared with the case where the second electrolyte membrane 40 is formed directly on the electrode 10. Thereby, peeling with the electrode 10 and the electrolyte membrane 20 can be suppressed.

  Next, an electrode-electrolyte membrane assembly 50a according to a second embodiment of the present invention will be described. FIG. 3 is a schematic cross-sectional view showing an electrode-electrolyte membrane assembly 50a according to a second embodiment of the present invention. The electrode-electrolyte membrane assembly 50a shown in FIG. 3 is different from the electrode-electrolyte membrane assembly 50 shown in FIG. 1 in that an electrolyte membrane 20a is provided instead of the electrolyte membrane 20. Other configurations are the same as those of the electrode-electrolyte membrane assembly 50 shown in FIG.

  The electrolyte membrane 20a includes a first electrolyte membrane 30a provided on the electrode 10, a second electrolyte membrane 40a provided on the first electrolyte membrane 30a, and a third electrolyte membrane provided on the second electrolyte membrane 40a. 45a. The first electrolyte membrane 30a is composed of an electrolyte having a smaller grain boundary resistance than the electrolyte constituting the second electrolyte membrane 40a. The second electrolyte membrane 40a is made of an electrolyte having a smaller grain boundary resistance than the electrolyte constituting the third electrolyte membrane 45a.

  Also in the electrode-electrolyte membrane assembly 50 a according to the present example, an electrolyte having a low grain boundary resistance is disposed at a position close to the electrode 10. Therefore, the conductivity of the electrolyte membrane 20a can be improved. The first electrolyte membrane 30a, the second electrolyte membrane 40a, and the third electrolyte membrane 45a may have higher sinterability, more sintering aid may be added, and a lattice constant of the electrode 10 It may be close to a constant. In this case, generation of fine crystals in the vicinity of the electrode 10 can be suppressed.

  Next, an electrode-electrolyte membrane assembly 50b according to a third embodiment of the present invention will be described. FIG. 4 is a schematic cross-sectional view showing an electrode-electrolyte membrane assembly 50b according to a third embodiment of the present invention. An electrode-electrolyte membrane assembly 50b shown in FIG. 4 is different from the electrode-electrolyte membrane assembly 50 shown in FIG. 1 in that an electrolyte membrane 20b is provided instead of the electrolyte membrane 20. Other configurations are the same as those of the electrode-electrolyte membrane assembly 50 shown in FIG.

  The electrolyte constituting the electrolyte membrane 20b has a lower grain boundary resistance as it is closer to the electrode 10. Therefore, the conductivity of the electrolyte membrane 20a can be improved. The electrolyte constituting the electrolyte membrane 20b may have higher sinterability as it is closer to the electrode 10, the amount of sintering aid added may be larger, and the lattice constant may be closer to the lattice constant of the electrode 10. . In this case, generation of fine crystals in the vicinity of the electrode 10 can be suppressed.

  Next, an electrode-electrolyte membrane assembly 50c according to a fourth embodiment of the present invention will be described. FIG. 5 is a schematic cross-sectional view showing an electrode-electrolyte membrane assembly 50c according to a fourth embodiment of the present invention. An electrode-electrolyte membrane assembly 50c shown in FIG. 5 is different from the electrode-electrolyte membrane assembly 50 shown in FIG. 1 in that an electrolyte membrane 20c is provided instead of the electrolyte membrane 20. The electrolyte membrane 20c shown in FIG. 5 is different from the electrolyte membrane 20 shown in FIG. 1 in that the first electrolyte membrane 30c is provided instead of the first electrolyte membrane 30. Other configurations are the same as those of the electrode-electrolyte membrane assembly 50 shown in FIG.

  The first electrolyte membrane 30c shown in FIG. 5 is different from the first electrolyte membrane 30 shown in FIG. 1 in that the film thickness near the center on the electrode 10 is thinner than the film thickness near the periphery. For example, the first electrolyte membrane 30c shown in FIG. 5 has a shape such that the film thickness gradually increases from the center to the periphery.

  In the electrode-electrolyte membrane assembly 50c according to the present example, when the first electrolyte membrane 30c is formed by the vapor deposition method, the temperature near the center of the first electrolyte membrane 30c is compared with that near the periphery. It becomes hot. Therefore, since the vicinity of the center of the first electrolyte membrane 30c is crystallized earlier than the vicinity of the periphery, the crystal grain size near the center of the first electrolyte membrane 30c is compared with the crystal grain size near the periphery. growing. Thereby, the film thickness near the center of the first electrolyte membrane 30c can be made thinner than the film thickness near the periphery. In this case, the ratio of the second electrolyte membrane 40 near the center in the electrolyte membrane 20c is increased. As a result, the conductivity of the electrolyte membrane 20c is increased.

1 is a schematic cross-sectional view showing an electrode-electrolyte membrane assembly according to a first embodiment of the present invention. It is typical sectional drawing which shows the manufacturing method of the electrode-electrolyte membrane assembly which concerns on 1st Example. It is typical sectional drawing which shows the electrode-electrolyte membrane assembly | attachment which concerns on 2nd Example. It is a typical sectional view showing the electrode-electrolyte membrane zygote concerning the 3rd example. It is typical sectional drawing which shows the electrode-electrolyte membrane assembly which concerns on 4th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrode 20 Electrolyte membrane 30 1st electrolyte membrane 40 2nd electrolyte membrane 45 3rd electrolyte membrane 50 Electrode-electrolyte membrane assembly

Claims (10)

Electrodes,
A first electrolyte membrane provided on the electrode;
A second electrolyte membrane provided on the first electrolyte membrane,
The electrode-electrolyte membrane assembly, wherein the grain boundary resistance of the electrolyte constituting the first electrolyte membrane is smaller than the grain boundary resistance of the electrolyte constituting the second electrolyte membrane.   The electrode-electrolyte membrane assembly according to claim 1, wherein the electrolyte constituting the first electrolyte membrane has a higher sinterability than the electrolyte constituting the second electrolyte membrane.   2. The electrode-electrolyte membrane assembly according to claim 1, wherein the electrolyte constituting the first electrolyte membrane includes the electrolyte constituting the second electrolyte membrane as a base material and a sintering aid. 3.   2. The electrode-electrolyte according to claim 1, wherein the lattice constant of the electrolyte constituting the first electrolyte membrane is closer to the lattice constant of the electrode than the lattice constant of the electrolyte constituting the second electrolyte membrane. Membrane assembly.   5. The electrode according to claim 1, wherein the electrode is a hydrogen separation membrane having hydrogen permeability, and the first electrolyte membrane and the second electrolyte membrane are made of an electrolyte having proton conductivity. Electrode-electrolyte membrane assembly. Forming a first electrolyte membrane on the electrode;
Forming a second electrolyte membrane on the first electrolyte membrane,
The method for producing an electrode-electrolyte membrane assembly, wherein the grain boundary resistance of the electrolyte constituting the first electrolyte membrane is smaller than the grain boundary resistance of the electrolyte constituting the second electrolyte membrane.   The method for producing an electrode-electrolyte membrane assembly according to claim 6, wherein the electrolyte constituting the first electrolyte membrane has a higher sinterability than the electrolyte constituting the second electrolyte membrane.   7. The electrode-electrolyte membrane assembly according to claim 6, wherein the electrolyte that constitutes the first electrolyte membrane includes the electrolyte that constitutes the second electrolyte membrane as a base material and includes a sintering aid. Method.   7. The electrode-electrolyte according to claim 6, wherein the lattice constant of the electrolyte constituting the first electrolyte membrane is closer to the lattice constant of the electrode than the lattice constant of the electrolyte constituting the second electrolyte membrane. A method for producing a membrane assembly.   10. The electrode according to claim 6, wherein the electrode is a hydrogen separation membrane having hydrogen permeability, and the first electrolyte membrane and the second electrolyte membrane are made of an electrolyte having proton conductivity. A method for producing an electrode-electrolyte membrane assembly.

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