Electrochemical device and method for manufacturing same

Abstract

[Problem] To provide an electrochemical device in which diffusion resistance of an electrolyte part is suppressed. [Solution] This electrochemical device includes: a porous base material which has conductivity; a glass electrolyte layer which is provided on the surface of the porous base material; and a conductor which is provided on the surface of the glass electrolyte layer. The resistance of the ion conduction of the glass electrolyte layer is 10 Ωcm2 or less. The reaction resistance of the interface between the porous base material and the glass electrolyte layer is 10 Ωcm2 or less. It is preferable that the thickness of the glass electrolyte layer is 0.2 mm or less. This electrochemical device can be used as a fuel cell, an electrolysis cell, and the like.

Description

Electrochemical device and method for manufacturing the same Cross Reference

[0001] This application claims priority in Japan based on Japanese Patent Application No. 2023-189687, filed on November 6, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to electrochemical devices suitable for operation at intermediate temperatures.

[0003] Electrochemical devices such as fuel cells and electrolysis cells that can operate at moderate temperatures of around 300°C are expected to reduce system costs and improve reaction efficiency, and are therefore expected to be next-generation energy conversion technologies. Meanwhile, proton-conducting phosphate glass is known to function as an electrolyte (Patent Document 1). However, no practical electrochemical devices utilizing this proton-conducting phosphate glass existed.

[0004] To commercialize this electrochemical device, a technology is needed to thin the electrolyte and reduce the resistance of ionic conduction in the electrolyte. One reported method for thinning the electrolyte is to hot-press a glass electrolyte block a few millimeters in size onto a metal substrate. However, even when this method is applied to a porous conductive substrate, the glass is not easily slippery in the holes of the substrate, making it difficult to roll, and thus a thin glass electrolyte film cannot be formed on the substrate.

[0005] JP 2015-189603 A

[0006] The present application has been made in view of the above circumstances, and has as its object to provide an electrochemical device in which the resistance to ion conduction in the electrolyte portion is reduced, and a laminate constituting this electrochemical device.

[0007] The laminate of the present application is a laminate for an electrochemical device having a conductive porous substrate and a glass electrolyte layer provided on the surface of the porous substrate, and the ionic conduction resistance of the glass electrolyte layer is 10 Ωcm ２ The reaction resistance at the interface between the porous substrate and the glass electrolyte layer is 10 Ωcm or less. ２ The following is the result.

[0008] In another embodiment, the laminate further comprises a hydrogen-permeable metal thin film on at least the surface of the porous substrate on which the glass electrolyte layer is provided.

[0009] The method for manufacturing a laminate according to the present application is a method for manufacturing a laminate for an electrochemical device having a conductive porous substrate and a glass electrolyte layer provided on the surface of the porous substrate, and includes a heating and pressurizing step of placing a material powder for the glass electrolyte layer on the surface of the porous substrate and pressing the material powder against the porous substrate while maintaining the material powder at a temperature equal to or higher than the glass transition point, thereby forming a glass electrolyte layer on the surface of the porous substrate.

[0010] A method for manufacturing a laminate according to another embodiment further includes a film-forming step of forming a hydrogen-permeable metal thin film on at least one surface of the porous substrate prior to the heating and pressing step, and the heating and pressing step forms a glass electrolyte layer on the surface on which the hydrogen-permeable metal thin film has been formed in the film-forming step.

[0011] The electrochemical device of the present application is an electrochemical device having a conductive porous substrate, a glass electrolyte layer provided on the surface of the porous substrate, and a conductor provided on the surface of the glass electrolyte layer, wherein the resistance of ionic conduction of the glass electrolyte layer is 10 Ωcm ２ The reaction resistance at the interface between the porous substrate and the glass electrolyte layer is 10 Ωcm or less. ２ The following is the result.

[0012] In another embodiment of the electrochemical device, the porous substrate further comprises a hydrogen-permeable metal thin film at least on the surface on which the glass electrolyte layer is provided.

[0013] The method for manufacturing an electrochemical device of the present application is a method for manufacturing an electrochemical device having a conductive porous substrate, a glass electrolyte layer provided on the surface of the porous substrate, and a conductor provided on the surface of the glass electrolyte layer, and includes a heating and pressurizing step of placing a material powder for the glass electrolyte layer on the surface of the porous substrate and pressing the material powder against the porous substrate while maintaining the material powder at a temperature equal to or higher than the glass transition point, to form a glass electrolyte layer on the surface of the porous substrate, and a conductor forming step of forming a conductor on the surface of the glass electrolyte layer.

[0014] A method for manufacturing an electrochemical device according to another embodiment further includes a film-forming step of forming a hydrogen-permeable metal thin film on at least one surface of the porous substrate prior to the heating and pressurizing step, and the heating and pressurizing step forms a glass electrolyte layer on the surface on which the hydrogen-permeable metal thin film has been formed in the film-forming step.

[0015] The power generation method of the present application comprises supplying a hydrogen-containing gas to the porous substrate of the electrochemical device of the present application and supplying an oxygen-containing gas to the conductor, thereby causing the electrochemical device to generate electrical energy.

[0016] The reaction method of the present application is an electrochemical device of the present application in which the conductor is a catalytic metal that reduces a reactant with hydrogen ions to generate a product from the reactant, and while a DC voltage is applied between the porous substrate and the conductor, a hydrogen-containing gas is supplied to the porous substrate and a gas containing the reactant is supplied to the conductor, thereby generating a product from the reactant.

[0017] According to the present invention, it is possible to provide an electrochemical device in which the resistance to ion conduction in the electrolyte portion is reduced, a laminate constituting this electrochemical device, and a power generation method and a reaction method using this electrochemical device.

[0018] 1. An external image of the glass electrolyte layer side of the laminate of Example 1. A cross-sectional SEM image of the laminate of Example 1. An enlarged view of the cross-sectional SEM image of FIG. 2. A Nyquist plot of the laminate of Example 1. A Nyquist plot of the glass electrolyte plate of a reference example. A graph showing the fuel cell power generation characteristics of the electrochemical cell of Example 2. A cross-sectional schematic diagram of a reaction device including the electrochemical cell of Example 3. A graph showing the relationship between the applied voltage and current density of the electrochemical cell of Example 3. A graph showing the relationship between the applied voltage and detected gas concentration of the electrochemical cell of Example 3. A graph showing the relationship between the applied voltage and Faraday efficiency of the electrochemical cell of Example 3. A cross-sectional schematic diagram of the laminate of Example 4. A Nyquist plot of the electrochemical cell of Example 5 under conditions of a cell voltage of 0.3 V (12 A) and an open circuit electromotive force (OCV: 1.07 V) (12 B). A graph showing the fuel cell power generation characteristics of the electrochemical cell of Example 5. A graph showing the relationship between the applied voltage and current density of the electrochemical cell of Example 6. Graph showing the relationship between the applied voltage and the detected gas concentration in the electrochemical cell of Example 6. Graph showing the relationship between the applied voltage and the Faraday efficiency in the electrochemical cell of Example 6. Graph showing the relationship between the applied voltage and the current density in the electrochemical cell of Example 7. Graph showing the relationship between the applied voltage and the detected gas concentration in the electrochemical cell of Example 7. Graph showing the relationship between the applied voltage and the Faraday efficiency in the electrochemical cell of Example 7.

[0019] Hereinafter, the laminate, laminate manufacturing method, electrochemical device, electrochemical device manufacturing method, power generation method, and reaction method of the present application will be described based on embodiments and examples, with appropriate reference to the drawings. When a numerical range is expressed using "to" between two numerical values, these two numerical values ​​are also included in this numerical range. Note that duplicated explanations will be omitted as appropriate.

[0020] The laminate of the embodiment of the present application includes a porous substrate and a glass electrolyte layer. The laminate of the embodiment is used in an electrochemical device. An electrochemical device is a device that converts electrical energy into chemical energy and vice versa. Examples of electrochemical devices include storage batteries, fuel cells, light-emitting cells, and electrolyzers (electrolysis cells). The glass electrolyte layer is provided on the surface of the porous substrate. The porous substrate is a porous substrate having a plate shape or a porous structure having a rectangular parallelepiped shape.

[0021] Considering rigidity and gas diffusibility, the thickness of the porous substrate is preferably 0.2 mm to 1.0 mm. To prevent excessive penetration of the electrolyte into the glass, the pore size of the porous substrate is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 20 μm or less. This pore size is desirably small as long as it does not impair gas diffusibility. This pore size is the number average value of the pore size distribution measured, for example, by gas adsorption method.

[0022] The porous substrate is electrically conductive. The electrical resistance of the electrically conductive porous body is 0.05 Ω cm. ２ ~0.5Ωcm ２ However, the electrical resistance of the porous substrate of the embodiment is 0.2 Ω cm ２ Preferably, the porous substrate is made of a highly rigid material composed of a composite material of ceramics and metal, in order to prevent cracking of the glass electrolyte layer due to bending of the porous substrate.

[0023] When a composite material of ceramic and metal is used, the ceramic used for the porous substrate is preferably an ion-conductive ceramic, more preferably gadolinium-doped ceria (GDC), yttria-doped zirconia (YSZ), yttrium-doped barium zirconate, ytterbium-doped barium zirconate, or the like, and even more preferably GDC. Examples of the composite material include Ni-GDC and Ni-YSZ, of which Ni-GDC is preferred. When the porous substrate is made of a metal, it is preferably a material whose metallic state is stable in a reducing atmosphere, more preferably a metal such as iron or nickel, or an alloy such as stainless steel, and in the case of stainless steel, even more preferably austenitic stainless steel.

[0024] The porous substrate preferably further comprises a hydrogen-permeable metal thin film on at least the surface on which the glass electrolyte layer is provided. That is, in this case, the porous substrate and the glass electrolyte layer are laminated in the laminate via the hydrogen-permeable metal thin film on the porous substrate. The thickness of the hydrogen-permeable metal thin film is not particularly limited, but is preferably 20 nm to 500 nm, more preferably 30 nm to 400 nm, and even more preferably 50 nm to 300 nm. Forming a hydrogen-permeable metal thin film on the porous substrate can facilitate the adsorption and dissociation of hydrogen gas and the supply of it to the glass electrolyte when the laminate is used in an electrochemical device. Conversely, it can also facilitate the absorption of hydrogen gas from the glass electrolyte. This allows for more efficient and smooth migration of protons (hydrogen ions) at the interface between the porous substrate and the glass electrolyte, ultimately contributing to an increase in the current value.

[0025] The hydrogen-permeable metal thin film preferably contains palladium (Pd). The hydrogen-permeable metal may be not only palladium (Pd) but also an alloy containing palladium as one of its materials. Such alloys are preferably palladium-silver (Pd-Ag) alloy, palladium-yttrium (Pd-Y) alloy, palladium-platinum (Pd-Pt) alloy, palladium-copper (Pd-Cu) alloy, etc., and more preferably palladium-silver (Pd-Ag) alloy and palladium-yttrium (Pd-Y) alloy. Furthermore, examples of hydrogen-permeable metals other than palladium include Group 5 metals such as vanadium (V), niobium (Nb), and tantalum (Ta), and similarly, alloys containing these metals as one of their materials may also be used as appropriate.

[0026] The ionic conduction resistance of the glass electrolyte layer is 10 Ω cm ２ The ionic conduction resistance of the glass electrolyte layer is 1 Ω cm ２ ~8Ωcm ２ The reaction resistance at the interface between the porous substrate and the glass electrolyte layer is preferably 10 Ωcm. ２ The reaction resistance of this interface is 1 Ωcm ２ ~8Ωcm ２It is preferable that the glass electrolyte layer has a low ionic conduction resistance and a low reaction resistance at the interface between the porous substrate and the glass electrolyte layer. A laminate having such low ionic conduction resistance in the glass electrolyte layer and a low reaction resistance at the interface between the porous substrate and the glass electrolyte layer can be obtained by the laminate manufacturing method described below. The glass electrolyte layer is an amorphous layered material that allows ions such as protons (hydrogen ions) to pass through. The amorphous nature of the glass electrolyte layer can be confirmed by the absence of clear diffraction in X-ray diffraction analysis.

[0027] The ionic conductivity of the glass electrolyte layer is 1 × 10 －３ SCM －１ It is preferable that the ratio is 5×10 or more. －３ SCM －１ When the glass electrolyte layer is used as a proton conductor, the proton conductivity of the glass electrolyte layer is preferably 1×10 or more. －３ SCM －１ It is preferable that the ratio is 5×10 or more. －３ SCM －１ More preferably, the thickness of the glass electrolyte layer is 0.2 mm or less, more preferably 5 μm to 0.2 mm, and even more preferably 5 μm to 50 μm. Examples of the glass electrolyte of the embodiment include ion-conductive phosphate glass, ion-conductive silicate glass, and ion-conductive borate glass. These are proton conductors.

[0028] The glass electrolyte layer preferably contains ion-conductive phosphate glass, which has the highest proton conductivity among the oxide glasses. Some of these glasses are represented by the following general formula (I): ２ O-M ｍ O ｎ ... (I) (A represents an alkali metal such as Li, Na, or K, M represents various elements such as polyvalent electropositive elements such as Al, B, Si, P, Ge, or Ce, and m and n are each any integer.)

[0029] Among the above glasses, a proton-conducting phosphate glass is preferably obtained by substituting at least a portion of the alkali metal ions derived from the alkali metal oxide with protons in a glass material containing an alkali metal oxide, an oxide of a polyvalent electropositive element that exists in a single oxidation state and not in multiple oxidation states, and a phosphorus oxide in the glass composition. The alkali metal oxide is preferably at least one oxide selected from the group consisting of lithium oxide, sodium oxide, and potassium oxide, and more preferably sodium oxide.

[0030] The oxide of the polyvalent electropositive element is preferably at least one selected from the group consisting of aluminum oxide, gallium oxide, scandium oxide, yttrium oxide, lanthanum oxide, lanthanide oxide, and tantalum oxide, more preferably a lanthanide oxide, and even more preferably cerium oxide. The glass material is preferably at least one selected from the group consisting of an oxide of a divalent metal, silicon oxide, tellurium oxide, and zirconium oxide, more preferably a divalent metal oxide, and even more preferably barium oxide.

[0031] A laminate manufacturing method according to an embodiment of the present application is a method for manufacturing a laminate for an electrochemical device having a conductive porous substrate and a glass electrolyte layer provided on the surface of the porous substrate. The laminate manufacturing method according to the embodiment includes a heating and pressurizing step. In the heating and pressurizing step, a material powder for the glass electrolyte layer is placed on the surface of the porous substrate, and the material powder is pressed against the porous substrate while being maintained at a temperature equal to or higher than the glass transition point, thereby forming a glass electrolyte layer on the surface of the porous substrate.

[0032] The material powder for the glass electrolyte layer is obtained by crushing ion-conductive glass gobs. When the glass electrolyte layer is used as a proton conductor, the glass gobs are crushed after replacing the alkaline components with protons. The particle size of the material powder for the glass electrolyte layer is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 20 μm or less. The glass gobs can be crushed into powder with a particle size of 1 μm.

[0033] The "material powder having a particle size of D μm or less" may be a material powder that has passed through a sieve with an opening size of D μm, or a material powder whose median value of the particle size distribution measured using a scanning electron microscope or dynamic light scattering (DLS) is D μm or less. The particle size of the material powder is, for example, the median value of the particle size distribution measured using a scanning electron microscope or the median value of the particle size distribution measured using dynamic light scattering (DLS).

[0034] In the process of placing the material powder for the glass electrolyte layer on the surface of the porous substrate, the material powder is spread as uniformly and thinly as possible on the surface of the porous substrate. The subsequent heating and pressurization causes the material powder to fuse together, resulting in a dense, smooth, and thin glass electrolyte layer. The material powder is pressed using a pressing device. After the porous substrate with the material powder placed on it is placed in the pressing device, the pressing plate of the pressing device, heated to a predetermined temperature, is used to press the material powder with a predetermined load for a predetermined time. The pressing plate is then removed from the glass electrolyte layer, and the temperature of the glass electrolyte layer is lowered. In this way, a glass electrolyte layer is formed on the surface of the porous substrate.

[0035] The predetermined temperature is equal to or higher than the glass transition point of the material powder (e.g., 250°C to 300°C), preferably several tens of degrees Celsius higher than the glass transition point. The predetermined temperature is preferably 400°C or lower, more preferably 350°C or lower. The predetermined load is approximately several kPa to several tens of kPa. The predetermined time is approximately several minutes to several tens of minutes. Conventional laminates including a ceramic electrolyte require integral firing at approximately 1300°C to 1400°C, but the laminate manufacturing method of the embodiment allows a laminate to be obtained at a temperature lower than this temperature and in a short time. Furthermore, the laminate manufacturing method of the embodiment allows a large laminate with a diameter of several tens of mm to several tens of cm to be obtained.

[0036] The method for producing a laminate according to an embodiment of the present application preferably further includes a film-forming step of forming a hydrogen-permeable metal thin film on at least one surface of the porous substrate prior to the heating and pressing step. When the film-forming step is included, the glass electrolyte layer is formed on the surface on which the hydrogen-permeable metal thin film has been formed in the heating and pressing step. Various known methods can be used to form the hydrogen-permeable metal thin film on the surface of the porous substrate, including physical vapor deposition methods such as vacuum deposition, sputtering, and ion plating, with sputtering being preferred.

[0037] The electrochemical device according to the embodiment of the present application comprises a porous substrate having electrical conductivity, a glass electrolyte layer provided on the surface of the porous substrate, and a conductor provided on the surface of the glass electrolyte layer. The conductor has an electrical conductivity of 1 Scm －１ ~1 x 10 ６ SCM －１ The conductor is a material of the formula (1). Examples of the conductor include metals, conductive oxides, and composites thereof. The ionic resistance of the glass electrolyte layer is 10 Ω cm. ２ The reaction resistance at the interface between the porous substrate and the glass electrolyte layer is 10 Ωcm or less. ２ The following is the result.

[0038] The electrochemical device of the embodiment may further include a fuel supply unit that supplies a hydrogen-containing gas to the porous substrate and an air supply unit that supplies an oxygen-containing gas to the conductor. The hydrogen-containing gas is a gas containing hydrogen atoms, and may be, for example, a gas containing hydrogen gas or a gas containing water vapor. The oxygen-containing gas is a gas containing oxygen gas, such as air. This electrochemical device can be used as a fuel cell. That is, the power generation method of the embodiment of the present application supplies a hydrogen-containing gas to the porous substrate of the electrochemical device of the present application and supplies an oxygen-containing gas to the conductor, thereby generating electrical energy in the electrochemical device.

[0039] In the electrochemical device of the embodiment, the conductor may be a catalytic metal that reduces a reactant with hydrogen ions to produce a product from the reactant. Examples of such catalytic metals include Ru and Ni, which reduce carbon dioxide with hydrogen ions to produce methane and carbon monoxide, Pt and Pd, which reduce carbon dioxide with hydrogen ions to produce carbon monoxide, and Ru, which reduces nitrogen with hydrogen ions to produce ammonia. This electrochemical device can be used as an electrolysis cell.

[0040] Furthermore, an electrochemical device according to another embodiment preferably further comprises a hydrogen-permeable metal thin film on at least the surface of the porous substrate on which the glass electrolyte layer is provided. Preferably, the conductor may contain an ion-conductive material. The ion-conductive material contained in the conductor may be the same as the glass electrolyte contained in the glass electrolyte layer described above, or may be a different glass electrolyte. Furthermore, the ion-conductive material is not limited to glass electrolytes, and various known ion-conductive materials may be used as appropriate.

[0041] In a reaction method according to an embodiment of the present application, a hydrogen-containing gas is supplied to the porous substrate while a DC voltage is applied between the porous substrate and the conductor, and a gas containing a reactant is supplied to the conductor, thereby generating a product from the reactant. Furthermore, this electrochemical device, which can be used as an electrolytic cell, may further include a hydrogen supply unit that supplies a hydrogen-containing gas, a reactant supply unit that supplies a reactant-containing gas to the conductor, and a power source that applies a DC voltage between the porous substrate and the conductor. The reactant-containing gas is a gas containing the reactant. Furthermore, the reaction method may preferably include water vapor as the hydrogen-containing gas.

[0042] A method for manufacturing an electrochemical device according to an embodiment of the present application is a method for manufacturing an electrochemical device having a conductive porous substrate, a glass electrolyte layer provided on the surface of the porous substrate, and a conductor provided on the surface of the glass electrolyte layer. The method for manufacturing an electrochemical device according to the embodiment includes a heating and pressurizing step and a conductor forming step. In the heating and pressurizing step, a material powder for the glass electrolyte layer is placed on the surface of the porous substrate, and the material powder is pressed against the porous substrate while being kept at a temperature equal to or higher than the glass transition point, thereby forming a glass electrolyte layer on the surface of the porous substrate.

[0043] In addition, the method for manufacturing an electrochemical device according to another embodiment preferably further includes a film-forming step of forming a hydrogen-permeable metal thin film on at least one surface of the porous substrate prior to the heating and pressurizing step. When the film-forming step is included, the glass electrolyte layer is formed on the surface on which the hydrogen-permeable metal thin film is formed in the heating and pressurizing step.

[0044] In the conductor forming step, a conductor is formed on the surface of the glass electrolyte layer. Examples of methods for forming a conductor on the surface of the glass electrolyte layer include a method of applying a conductor paste to the surface of the glass electrolyte layer and drying it, a method of pressing a conductor layer formed in the shape of a conductive sheet for current collection against the glass electrolyte layer, and a physical vapor deposition method for a conductor such as sputtering or pulsed laser deposition.

[0045] Example 1: Preparation and evaluation of laminate (preparation of porous substrate) Using ethanol as a dispersion medium, 14 g of NiO (FUJIFILM WAKO) and Gd-doped ceria (Gd ０．１ Ce ０．９ O ２－ｄ A slurry containing 6 g of a polymer bead pore former (MX-300, Soken Chemical) with an average particle size of 3 μm was obtained. This slurry was dried, uniaxially press-molded at 30 MPa to a diameter of 20 mm, and then fired at 1300°C for 5 hours to obtain a NiO-GDC porous substrate. ２ The NiO-GDC porous substrate was subjected to reduction treatment at 700° C. for 2 hours in the chamber, to obtain a Ni-GDC porous substrate having a thickness of about 0.8 mm, in which NiO had been reduced to metallic Ni.

[0046] (Preparation of glass electrolyte powder) A glass electrolyte powder having a composition of 36NaO １／２ -4NbO ５／２ -2BaO-4CeO ２ -4GeO ２ -48PO ５／２ This glass mass was subjected to alkali-proton exchange (APS) to obtain 36HO １／２ -4NbO ５／２ -2BaO-4CeO ２ -4GeO ２ -48PO ５／２ This post-APS glass was crushed using an alumina mortar and pestle and passed through a sieve with an opening diameter of 45 μm to obtain a glass electrolyte powder with a particle size of 45 μm or less, which is used as a material for the proton-conductive electrolyte.

[0047] (Formation of a Glass Electrolyte Layer on a Porous Substrate) Masking tape was applied to the periphery of the surface of the Ni-GDC porous substrate so as to protrude 0.1 mm above the surface of the Ni-GDC porous substrate. The dried glass electrolyte powder was filled onto the surface of the Ni-GDC porous substrate inside the masking tape, and the upper surface of the glass electrolyte powder was then leveled by leveling. A mirror-polished glassy carbon pressure plate was maintained at 310°C, approximately 50°C higher than the glass transition temperature of the glass electrolyte powder, approximately 260°C, while applying a load of 12 kN to 15 kN to the glass electrolyte powder using the pressure plate, to obtain a laminate of Example 1 in which a glass electrolyte layer approximately 0.1 mm thick was formed on the Ni-GDC porous substrate.

[0048] FIG. 1 shows the appearance of the glass electrolyte layer side of the laminate of Example 1. As shown in FIG. 1, light reflection from the glass electrolyte layer was observed, confirming that the surface of the glass electrolyte layer was smooth. FIG. 2 is a cross-sectional SEM image of this laminate. FIG. 3 is an enlarged cross-sectional SEM image of the vicinity of the interface between the Ni-GDC porous substrate and the glass electrolyte layer in FIG. 2. As shown in FIG. 3, it was confirmed that a dense glass electrolyte layer without through-holes was formed, and that the glass electrolyte layer and the Ni-GDC porous substrate were in close contact with each other. Furthermore, the glass electrolyte layer did not contain grain boundaries such as those found in ceramic electrolytes. In other words, the glass electrolyte layer had no grain boundary resistance.

[0049] (Evaluation of Laminate) Using an electrochemical measurement device (biologic, SP-300 (hereinafter the same), frequency 1 MHz to 0.1 Hz, amplitude 20 mV), AC impedance measurement of the laminate of Example 1 was carried out in hydrogen at 300°C. The Nyquist plot based on this AC impedance measurement is shown in Figure 4. As shown in Figure 4, the ionic conduction resistance of the glass electrolyte layer portion of the laminate of Example 1 was 6.4 Ωcm ２ The proton conductivity calculated from the resistance of this ionic conduction was 2 × 10 －３ SCM －１ The proton conductivity was calculated by the following formula (II): σ=1 / R·t (II) where σ is the proton conductivity (Scm －１ ), R is the resistance of ionic conduction in the glass electrolyte layer (Ω cm ２ ), t is the thickness (cm) of the glass electrolyte layer. The reaction resistance at the interface between the Ni-GDC porous substrate and the glass electrolyte layer is 6.5 Ωcm. ２ It was.

[0050] On the other hand, the Nyquist plot of a glass electrolyte plate (Reference Example) having the same composition as the glass electrolyte layer of the laminate of Example 1 and a thickness of approximately 0.4 mm is shown in Figure 5. Figure 5 was obtained in the same manner as the laminate of Example 1. To measure the resistance of the glass electrolyte plate, a thin palladium film formed by magnetron sputtering was used as an electrode. As shown in Figure 5, the ionic conduction resistance of the glass electrolyte plate of the Reference Example was 24 Ω cm. ２ and the proton conductivity is 2×10 －３ SCM －１ The reaction resistance at the interface between the palladium thin film electrode and the glass electrolyte plate was 91 Ω cm ２ It was.

[0051] The proton conductivity of the glass electrolyte in the laminate of Example 1 was the same as that of the glass electrolyte plate of the Reference Example. In other words, in the laminate of Example 1, which had a dense glass electrolyte layer, the glass electrolyte was thinned without reducing the proton conductivity from the glass electrolyte plate made of a thick glass electrolyte. As a result, the laminate of Example 1 achieved the effect of reducing the resistance of ion conduction in the glass electrolyte due to the thinning of the glass electrolyte. Furthermore, in the laminate of Example 1, in which the porous substrate and the glass electrolyte were in close contact, the reaction resistance at the interface between the porous substrate and the glass electrolyte was extremely low. The laminate of the present application, which has low ion conduction resistance in the glass electrolyte and low reaction resistance at the interface between the porous substrate and the glass electrolyte while suppressing the reduction in proton conductivity, is suitable as a component of an electrochemical device involving proton conduction.

[0052] Example 2: Fabrication and Evaluation of Fuel Cell A viscous fluid containing Pt (Sigma-Aldrich, 205915, Pt-black) was applied to the surface of the glass electrolyte layer of the laminate of Example 1 and dried to obtain an electrochemical cell of Example 2 having a Pt electrode formed thereon. This electrochemical cell was used as a fuel cell. Specifically, hydrogen was flowed into the anode (porous substrate side) of this electrochemical cell, and oxygen was flowed into the cathode (Pt electrode side), and the power generation characteristics of this electrochemical cell at 300°C were measured using an electrochemical measurement device.

[0053] Figure 6 shows the current-voltage characteristics and current-output characteristics measured during fuel cell operation. As shown in Figure 6, the open circuit electromotive force (OCV) was 1.12 V and the maximum power density (Pmax) was 3.32 mW / cm ２ It was confirmed that the electrochemical cell of Example 2 functions as a fuel cell. Although the output density of the electrochemical cell of Example 2 is not particularly high, this electrochemical cell produced a high electromotive force close to the theoretical value that could not be obtained with conventional phosphoric acid fuel cells. It is believed that the laminate of the present invention, in which the dense glass electrolyte layer is in close contact with the porous substrate, provides the high performance of the electrochemical cell of the present invention.

[0054] Example 3: CO ２Fabrication and Evaluation of Electrolytic Cell A viscous fluid containing Ru (Sigma-Aldrich, 326712, Ru-black) was applied to the center of the surface of the glass electrolyte layer of the laminate of Example 1 and dried to obtain an electrochemical cell of Example 3 on which a Ru catalyst layer was formed. ２ The electrochemical cell was used as an electrolysis cell. Figure 7 shows a schematic cross section of a reactor in which this electrochemical cell was installed. That is, this electrochemical cell was installed in an alumina jig equipped with a hydrogen flow path that allowed hydrogen to contact the porous substrate and a carbon dioxide flow path that allowed carbon dioxide to contact the Ru catalyst layer.

[0055] The electrochemical cell had gold current-collecting meshes on the porous substrate surface and the Ru catalyst layer surface. Current-collecting wires extended from these current-collecting meshes toward the carbon dioxide flow path inlet, carbon dioxide flow path outlet, hydrogen flow path inlet, and hydrogen flow path outlet, as shown in FIG. 7 . A thermoplastic polyimide sheet and a heat-resistant sheet were placed on top of each other around the electrochemical cell to ensure airtightness of the cell. While applying a voltage of 0.5 V to 5.0 V to the electrochemical cell via the current-collecting wires, hydrogen containing water vapor was flowed into the porous substrate side and carbon dioxide was flowed into the Ru catalyst side. The current density of the electrochemical cell of Example 3 at 300°C was measured using an electrochemical measurement device. FIG. 8 shows the relationship between applied voltage and current density.

[0056] Furthermore, the gas flowing out from the carbon dioxide flow channel outlet was analyzed using a gas chromatograph (GC8860, manufactured by Agilent Technologies) equipped with an FID and a TCD. FIG. 9 shows the relationship between the applied voltage and the detected gas concentration. Furthermore, FIG. 10 shows the relationship between the applied voltage and the Faraday efficiency calculated from the current density and the detected gas concentration. The Faraday efficiency was calculated from the current density and the detected gas concentration using the following formula: Faraday efficiency = (detected gas concentration x gas flow rate / molar volume of gas) x number of reaction electrons / (current density / Faraday constant). Note that H ２ , C.H. ４ The reactive electron numbers of CO, CO, and CO are 2, 8, and 2, respectively.

[0057] As shown in Figures 8 to 10, as the voltage applied to the electrochemical cell increases, the current density and H ２ , C.H. ４ 10, when the applied voltage was 2.5 V or higher, the amount of H supplied to this electrochemical cell increased. ２ 80% of CO ２ The electrochemical cell of the present invention uses a reaction device as shown in FIG. ２ Only hydrogen gas can be supplied to the catalyst side gas containing 100% hydrogen. Therefore, a high hydrogen partial pressure reaction field can be formed locally on the catalyst surface, resulting in efficient CO ２ A transformation reaction can occur.

[0058] Example 4: Preparation and evaluation of laminate with palladium thin film (Formation of palladium thin film on porous substrate) The porous substrate and the glass electrolyte powder were prepared in the same manner as in Example 1. Before forming the glass electrolyte layer, a palladium thin film was deposited as a hydrogen-permeable metal thin film by sputtering on one side of the obtained Ni-GDC porous substrate.

[0059] Sputtering was performed using a magnetron sputtering device (MST-40T, manufactured by Vacuum Device Co., Ltd.). A 2-inch diameter pure metal Pd target was placed in the reaction vessel of the device, Ar was introduced at 0.8 Pa, and sputtering was performed by supplying a power of 40 W to 50 W. The thickness of the palladium thin film deposited by sputtering was approximately 200 nm.

[0060] Thereafter, a glass electrolyte layer was formed on the porous substrate in the same manner as in Example 1, and a laminate similar to that in Example 1 was obtained, except that a thin palladium film with a thickness of about 200 nm was provided between the glass electrolyte layer and the porous substrate. A cross-sectional schematic diagram of the laminate is shown in Figure 11.

[0061] Example 5: Fabrication and evaluation of a fuel cell using a laminate with a palladium thin film An electrochemical cell of Example 5 was obtained in which a composite electrode of a proton-conductive glass electrolyte and Pt was formed on the surface of the glass electrolyte layer of the laminate of Example 4. The composite electrode was formed as follows. First, 36NaO １／２ -4NbO ５／２ -2BaO-4CeO ２ -4GeO ２ -48PO ５／２ This glass mass was subjected to alkali-proton exchange (APS) to obtain 36HO １／２ -4NbO ５／２ -2BaO-4CeO ２ -4GeO ２ -48PO ５／２ This post-APS glass was dry-ground using an alumina mortar and pestle, and passed through a sieve with an opening diameter of 45 μm to obtain a glass electrolyte powder with a particle size of 45 μm or less, which is used as a material for the proton-conductive electrolyte.

[0062] Five mg of the glass electrolyte powder obtained as described above and a viscous fluid containing Pt (Sigma-Aldrich, 205915, Pt-black) were weighed out so that the mass ratio was 1:1, and the mixture was dispersed and mixed in 20 μL of ultrapure water by vibration stirring using a homogenizer (Hielscher, UP100H). A composite electrode was then formed by a drop-casting method. Specifically, the resulting dispersion solution was dropped onto the surface of the glass electrolyte layer on the laminate at room temperature. After dropping, the solvent was dried at room temperature to form a composite electrode in which the dispersoid solidified and precipitated. This electrochemical cell was used as a fuel cell. The electrochemical cell was subjected to the evaluation of fuel cell characteristics described below.

[0063] (Evaluation of fuel cell characteristics) Using an electrochemical measurement apparatus (biologic, SP-300, frequency 1 MHz to 0.1 Hz, amplitude 20 mV), AC impedance measurements of the electrochemical cell of Example 5 were carried out at 300°C under conditions of a cell voltage of 0.3 V and an open circuit electromotive force (OCV: 1.07 V). The gas atmosphere conditions for the measurements were a 100% hydrogen atmosphere on the anode (porous substrate) side and a 100% oxygen atmosphere on the cathode (composite electrode) side. A Nyquist plot based on this AC impedance measurement is shown in Figure 12. As shown in the plot measured at 0.3 V in Figure 12A, the ionic conduction resistance of the glass electrolyte layer portion of the electrochemical cell of Example 5 was 6.6 Ω cm ２ The proton conductivity calculated from the resistance of this ionic conduction was 2 × 10 －３ SCM －１ The proton conductivity was calculated in the same manner as above using the formula. The reaction resistance at the interface between the Ni-GDC porous substrate and the glass electrolyte layer was 6.1 Ωcm. ２ The plot in FIG. 12B shows a Nyquist plot measured under open circuit electromotive force conditions.

[0064] Figure 13 shows the current-voltage characteristics and current-output characteristics measured during fuel cell operation. As shown in Figure 13, the open circuit electromotive force (OCV) was 1.07 V and the maximum power density (Pmax) was 14.7 mW / cm ２ It was confirmed that the electrochemical cell of Example 5 functions as a fuel cell. The output density of the electrochemical cell of Example 5 was nearly five times that of the electrochemical cell of Example 2, and the current value was further increased. The electromotive force was also comparable to that of the electrochemical cell of Example 2.

[0065] Example 6: CO using stack with palladium thin film ２ Preparation and Evaluation of Electrolytic Cell A viscous fluid containing Ru (Sigma-Aldrich, 326712, Ru-black) was applied to the center of the surface of the glass electrolyte layer of the laminate of Example 4 and dried to obtain an electrochemical cell of Example 6 on which a Ru catalyst layer was formed. ２The electrochemical cell of Example 6 was placed in an alumina jig equipped with a hydrogen flow path that allowed gas containing hydrogen atoms to contact the porous substrate and a carbon dioxide flow path that allowed carbon dioxide to contact the Ru catalyst layer.

[0066] As in Example 3, in the reaction apparatus shown in Figure 7, a voltage of 0.5 V to 5.0 V was applied to the electrochemical cell via a current collector while 100% hydrogen gas was flowed into the porous substrate side and carbon dioxide was flowed into the Ru catalyst side. Under these conditions, the current density of the electrochemical cell of Example 6 at 300°C was measured using an electrochemical measurement device. Figure 14 shows the relationship between the applied voltage and the current density.

[0067] The detected gas concentration and the Faraday efficiency were measured and calculated in the same manner as in Example 3. The measurement results of the detected gas concentration are shown in Fig. 15, and the calculated Faraday efficiency is shown in Fig. 16.

[0068] In the electrochemical cell of Example 6, as the voltage applied to the electrochemical cell increases, the current density and H ２ , C.H. ４ , and the amount of CO detected further increased. Furthermore, when the applied voltage reached 1 V, the amount of H supplied to the electrochemical cell ２ 80% of CO ２ It has been used in the reaction with and has shown high faradaic efficiency.

[0069] Example 7: CO using stack with palladium thin film ２ Preparation and Evaluation of Electrolytic Cell An electrochemical cell was prepared in the same manner as in Example 6, except that argon gas containing 30% water vapor was used as the hydrogen-containing gas. ２ The current density of the electrochemical cell of Example 7 was measured at 300° C. in the same manner as in Example 6. Fig. 17 shows the relationship between the applied voltage and the current density.

[0070] The detected gas concentration and the Faraday efficiency were measured and calculated in the same manner as in Example 6. The measurement results of the detected gas concentration are shown in Fig. 18, and the calculated Faraday efficiency is shown in Fig. 19.

[0071] In the electrochemical cell of Example 7, even when water vapor was used as the hydrogen-containing gas, CO ２ From CO and CH ４ The reduction was confirmed.

[0072] The palladium thin film formed between the glass electrolyte layer and the porous substrate allows an electrochemical cell including a laminate in which the palladium thin film is formed to more efficiently utilize water vapor as a proton source.

Claims

1. A laminate for an electrochemical device comprising a conductive porous substrate and a glass electrolyte layer provided on the surface of the porous substrate, The ion conduction resistance of the glass electrolyte layer is 10 Ωcm. ２ The following: The reaction resistance at the interface between the porous substrate and the glass electrolyte layer is 10 Ωcm. ２ The following is the laminated structure.

2. In claim 1, A laminate in which the thickness of the glass electrolyte layer is 0.2 mm or less.

3. In claim 1 or 2, The porous substrate is a laminate composed of a material which is a composite of ceramics and metal.

4. In claim 1 or 2, The porous substrate is a laminate further comprising a hydrogen-permeable metal thin film on at least the side on which the glass electrolyte layer is provided.

5. In claim 4, The hydrogen-permeable metal thin film is a laminate containing palladium.

6. A method for manufacturing a laminate according to Claim 1, A method for manufacturing a laminate, comprising a heating and pressurizing step of placing the material powder for the glass electrolyte layer on the surface of the porous substrate, and pressing the material powder onto the porous substrate while maintaining the temperature of the material powder at or above the glass transition point to form the glass electrolyte layer on the surface of the porous substrate.

7. A method for manufacturing a laminate for an electrochemical device having a conductive porous substrate and a glass electrolyte layer provided on the surface of the porous substrate, A method for manufacturing a laminate, comprising a heating and pressing step of placing the material powder for the glass electrolyte layer on the surface of the porous substrate to a height of 0.2 mm or less, and pressing the material powder onto the porous substrate while maintaining the temperature of the material powder above the glass transition point to form the glass electrolyte layer on the surface of the porous substrate.

8. In claim 6 or 7, A method for manufacturing a laminate, wherein the temperature is 400°C or lower.

9. In claim 6 or 7, A method for producing a laminate in which the particle size of the material powder is 100 μm or less.

10. In claim 6 or 7, Prior to the heating and pressurizing step, the process further includes a film formation step of forming a hydrogen-permeable metal thin film on at least one surface of the porous substrate, The heating and pressing step is a method for manufacturing a laminate in which the glass electrolyte layer is formed on the side on which the hydrogen permeable metal thin film was formed in the film formation step.

11. An electrochemical device comprising a conductive porous substrate, a glass electrolyte layer provided on the surface of the porous substrate, and a conductor provided on the surface of the glass electrolyte layer, The ion conduction resistance of the glass electrolyte layer is 10 Ωcm. ２ The following: The reaction resistance at the interface between the porous substrate and the glass electrolyte layer is 10 Ωcm. ２ The following are electrochemical devices.

12. In claim 11, The system further comprises a fuel supply unit that supplies hydrogen-containing gas to the porous substrate and an air supply unit that supplies oxygen-containing gas to the conductor, A fuel cell is an electrochemical device.

13. In claim 11, The conductor is a catalytic metal that reduces the reactant with hydrogen ions and generates a product from the reactant. An electrochemical device, specifically an electrolytic cell.

14. In claim 13, An electrochemical device further comprising: a hydrogen supply unit that supplies a hydrogen-containing gas to the porous substrate; a reactant supply unit that supplies a reactant-containing gas to the conductor; and a power supply that applies a DC voltage between the porous substrate and the conductor.

15. In claim 11, The porous substrate further comprises a hydrogen-permeable metal thin film on at least the side on which the glass electrolyte layer is provided, making it an electrochemical device.

16. In claim 12, The aforementioned conductor is an electrochemical device containing an ion-conducting material.

17. A method for manufacturing an electrochemical device according to claim 11, A heating and pressurizing step in which the material powder for the glass electrolyte layer is placed on the surface of the porous substrate, and the material powder is pressed onto the porous substrate while maintaining the temperature of the material powder at or above the glass transition point, thereby forming the glass electrolyte layer on the surface of the porous substrate, A conductor formation step in which the conductor is formed on the surface of the glass electrolyte layer, A method for manufacturing an electrochemical device having [a certain characteristic].

18. A method for manufacturing an electrochemical device comprising a porous substrate having conductivity, a glass electrolyte layer provided on the surface of the porous substrate, and a conductor provided on the surface of the glass electrolyte layer, A heating and pressurizing step in which the material powder for the glass electrolyte layer is placed on the surface of the porous substrate to a height of 0.2 mm or less, and the material powder is pressed onto the porous substrate while maintaining the temperature of the material powder at or above the glass transition point, thereby forming the glass electrolyte layer on the surface of the porous substrate. A conductor formation step in which the conductor is formed on the surface of the glass electrolyte layer, A method for manufacturing an electrochemical device having [a certain characteristic].

19. In claim 17 or 18, Prior to the heating and pressurizing step, the process further includes a film formation step of forming a hydrogen-permeable metal thin film on at least one surface of the porous substrate, The heating and pressurizing step is a method for manufacturing an electrochemical device in which the glass electrolyte layer is formed on the side on which the hydrogen permeable metal thin film is deposited.

20. A method for generating electricity in which a hydrogen-containing gas is supplied to the porous substrate of the electrochemical device according to claim 11 or 15, and an oxygen-containing gas is supplied to the conductor, thereby generating electrical energy in the electrochemical device.

21. A reaction method for generating a product from a reactant, comprising applying a DC voltage between the porous substrate and the conductor of the electrochemical device according to claim 13 or 15, while supplying a hydrogen-containing gas to the porous substrate and supplying a gas containing a reactant to the conductor.

22. In claim 21, The hydrogen-containing gas is a reaction method that includes water vapor.