Solid oxide electrolysis cell membrane electrode and applications

Abstract

The application discloses a solid oxide electrolysis cell membrane electrode and application, and belongs to the field of solid oxide electrolysis cells. The membrane electrode is composed of a porous hydrogen electrode, a porous oxygen electrode, and a dense electrolyte layer between the hydrogen electrode and the oxygen electrode, wherein the electrolyte is a proton-conducting oxide, the electrolyte layer contains BaCe 1‑x‑y Zr x M y O 3‑ε layer and a BaZr 1‑m‑n Ce m M n O 3‑δ layer, wherein the BaCe 1‑x‑y Zr x M y O 3‑ε layer is connected with the porous hydrogen electrode. The electrode-electrolyte interface of the membrane electrode has good contact, the electrolysis cell has low ohmic resistance and polarization resistance, and the membrane electrode shows outstanding electrochemical performance in the aspects of hydrogen production by electrolysis of water vapor and power supply for preparation of synthesis gas.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide electrolytic cells, specifically relating to a membrane electrode for solid oxide electrolytic cells and its application. Background Technology

[0002] Solid oxide electrolyzers (SOECs) are considered the most efficient water electrolysis technology for hydrogen production, achieving an electrolytic efficiency of up to 100% and a system efficiency of up to 90%. To further reduce manufacturing costs and improve the stability of key components, SOECs based on proton-conducting electrolytes have attracted widespread attention in recent years. The proton conduction activation energy is 0.3–0.5 eV, lower than the oxygen ion conduction activation energy (0.8–0.9 eV), making it possible for proton-conducting electrolyte-based SOECs to maintain high performance at operating temperatures of 400–600 °C. However, in practical studies, it has been found that the membrane electrode assembly (MEA) based on proton-conducting electrolytes exhibits poor performance and fails to display the expected electrochemical properties. This is mainly due to the poor sintering activity of the proton-conducting electrolyte, requiring a high sintering temperature during MEA fabrication to densify the electrolyte, which disrupts the electrode-electrolyte interface, resulting in high ohmic resistance and polarization resistance of the electrolyzer. Therefore, how to reduce the sintering temperature of the MEA, focusing on reducing the densification temperature of the electrolyte membrane, is a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a solid oxide electrolytic cell membrane electrode and its application. This membrane electrode has a low sintering temperature and a low electrolyte layer densification temperature, thereby reducing the polarization resistance and ohmic resistance of the battery.

[0004] This invention provides a membrane electrode for a solid oxide electrolyzer, comprising a hydrogen electrode, an oxygen electrode, and an electrolyte layer located between the hydrogen and oxygen electrodes; the hydrogen electrode is a metal-proton conductive composite material, the oxygen electrode is a composite material with proton-electron-oxygen ion conductivity, and the electrolyte layer includes BaCe. 1-x-y Zr x M y O 3-ε Layers and BaZr 1-m-n Ce m M n O 3-δ Layer, the BaCe 1-x-y Zr x M y O 3-ε The layer is connected to the hydrogen electrode, and the BaCe 1-x-y Zr x M y O 3-ε Layers and BaZr 1-m-nCe m M n O 3-δ Layer connection, wherein the electrolyte layer is connected to the oxygen electrode; the BaCe 1-x-y Zr x M y O 3-ε Layers and the BaZr 1-m-n Ce m M n O 3-δ The layer is uniformly distributed in the electrolyte layer; wherein, 0≤x≤0.3, 0<y≤0.5, 0≤ε≤0.5, 0≤m≤0.3, 0<n≤0.5, 0≤δ≤0.5, and M is one or more of Y, Yb, Sm, Gd, Sc, In, and Pr, and the BaCe 1-x- y Zr x M y O 3-ε and the BaZr 1-m-n Ce m M n O 3-δ The M element in the equation remains the same.

[0005] Furthermore, the hydrogen electrode has a porous structure with a porosity of 35-50%; the oxygen electrode has a porous structure with a porosity of 30-45%; and the electrolyte has a density of 95%-100%.

[0006] Furthermore, in the electrolyte layer, BaCe 1-x-y Zr x M y O 3-ε Layers and BaZr 1-m-n Ce m M n O 3-δ The thickness of each layer is 1 to 10 micrometers.

[0007] Furthermore, in the electrolyte layer, BaCe 1-x-y Zr x M y O 3-ε Layers and BaZr 1-m-n Ce m M n O 3-δ The thickness of each layer is preferably 1 to 5 micrometers.

[0008] Furthermore, the BaCe electrolyte layer 1-x-y Zr x M y O 3-ε and BaZr 1-m-n Cem M n O 3-δ In this context, M is preferably one or more of Y, Yb, Sc, and In. The BaCe... 1-x-y Zr x M y O 3-ε In the given information, x is preferably 0.1 ≤ x ≤ 0.2, and y is preferably 0.05 ≤ y ≤ 0.2. The BaZr... 1-m-n Ce m M n O 3-δ In this case, m is preferably 0.1≤m≤0.2, and n is preferably 0.05≤n≤0.2.

[0009] Furthermore, the metal-proton conductive composite material includes a composite material composed of metal Ni or metal Cu and perovskite proton conductors; the proton-electron-oxygen ion conductive composite material includes a perovskite oxide with proton-electron-oxygen ion conductivity or a composite material composed of perovskite proton conductors and perovskite electron-oxygen ion mixed conductors.

[0010] This invention also provides a method for preparing a solid oxide electrolytic cell membrane electrode, comprising: applying BaCe... 1-x- y Zr x M y O 3-ε Layers and BaZr 1-m-n Ce m M n O 3-δ The layer forms an electrolyte, the BaCe 1-x-y Zr x M y O 3-ε The layer is connected to the hydrogen electrode, and the BaCe 1-x-y Zr x M y O 3-ε Layers and BaZr 1-m-n Ce m M n O 3-δ Layer bonding, co-sintering, and then on BaZr 1-m-n Ce m M n O 3-δ An oxygen electrode is coated onto the surface of the membrane, and then the oxygen electrode is sintered to obtain a membrane electrode.

[0011] Furthermore, the co-sintering temperature is 1200–1350°C.

[0012] Furthermore, the temperature of the sintered oxygen electrode is 800–1100°C.

[0013] During the membrane electrode sintering process, BaCe 1-x-y Zr x M y O 3-ε Layers and BaZr 1-m-n Ce m M n O 3-δ Layer reaction sintering forms a dense electrolyte layer with uniformly distributed components.

[0014] The present invention also provides an application of a solid oxide electrolytic cell membrane electrode or a solid oxide electrolytic cell membrane electrode prepared by the above preparation method, wherein the membrane electrode is used in the electrolysis of steam to produce hydrogen, the electrolysis of carbon dioxide to produce carbon monoxide, or the electrolysis of steam and carbon dioxide to produce syngas.

[0015] Furthermore, the membrane electrode is suitable for use with fuel cell stacks that have a planar, tubular, or flat tubular structure.

[0016] The typical operating temperature of the membrane electrode is 350–650°C.

[0017] Beneficial effects of the present invention

[0018] (1) In the field of proton-conductive membrane electrodes, the difficulty in sintering electrolyte films and the high densification temperature are important bottlenecks restricting the development of this technology. This invention, based on the understanding of the sintering mechanism of proton-conductive electrolytes, incorporates BaCe in the electrolyte layer during membrane electrode fabrication. 1-x-y Zr x M y O 3-ε Layers and BaZr 1-m-n Ce m M n O 3-δ The layer utilizes the differences in thermodynamic stability and sintering activity between the two components, allowing elemental reaction diffusion at high temperatures to achieve reaction sintering at relatively low temperatures, thus forming a dense electrolyte layer.

[0019] (2) To further optimize the effect of the present invention, the electrolyte layer of the present invention is set as BaCe 1-x-y Zr x M y O 3-ε Layers and BaZr 1-m-n Ce m M n O 3-δ Layer, in which BaCe 1-x-y Zr x M y O 3-ε The layer is connected to the porous hydrogen electrode, BaZr 1-m-n Ce m Mn O 3-δ The layer is connected to the porous oxygen electrode. During the co-firing process of the membrane electrode, the highly sintering active BaCe... 1-x-y Zr x M y O 3-ε The combined action of the layer and the porous hydrogen electrode provides greater shrinkage force, thereby promoting the low-temperature dense sintering of the final electrolyte layer and reducing the sintering temperature.

[0020] (3) Due to the reduction in the densification temperature of the electrolyte layer, the membrane electrode of the present invention only needs to be sintered at 1200 to 1350°C, which well maintains the porosity of the electrode during the electrode-electrolyte co-firing process and improves the electrode-electrolyte interface contact, thereby reducing the polarization resistance and ohmic resistance of the battery, and showing outstanding electrolytic performance at 350 to 600°C. Detailed Implementation

[0021] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0022] Comparative Example 1

[0023] A solid oxide electrolytic cell membrane electrode, wherein the hydrogen electrode is a NiO-BaCe alloy with a mass ratio of 6:4. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 The composite material has a hydrogen electrode porosity of 40% and an electrolyte layer of 10 micrometers BaCe. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 The density is 96%, and the oxygen electrode is Sm2O3 with a mass ratio of 5:5. 0.5 Sr 0.5 CoO 2.6 -BaZr 0.8 Y 0.2 O 2.9 The composite material has an oxygen electrode porosity of 40%. The hydrogen electrode and electrolyte layer are co-fired at 1450℃, and the oxygen electrode is sintered at 1000℃.

[0024] The membrane electrode operates in steam electrolysis mode, and at an electrolysis voltage of 1.3V and an operating temperature of 600℃, the electrolysis current density reaches -0.72 A / cm². 2 .

[0025] Comparative Example 2

[0026] A solid oxide electrolytic cell membrane electrode, wherein the hydrogen electrode is a NiO-BaZr mixture with a mass ratio of 6:4.0.8 Y 0.2 O 2.6 The composite material has a hydrogen electrode porosity of 40% and an electrolyte layer of 10 micrometers of BaZr. 0.8 Y 0.2 O 2.6 The density is 96%, and the oxygen electrode is Sm2O3 with a mass ratio of 5:5. 0.5 Sr 0.5 CoO 2.6 -BaZr 0.8 Y 0.2 O 2.6 The composite material has an oxygen electrode porosity of 40%. The co-firing temperature of the hydrogen electrode and electrolyte layer is 1520℃, and the sintering temperature of the oxygen electrode is 1000℃.

[0027] The membrane electrode operates in steam electrolysis mode, and at an electrolysis voltage of 1.3V and an operating temperature of 600℃, the electrolysis current density reaches -0.5A / cm². 2 .

[0028] Comparative Example 3

[0029] A solid oxide electrolytic cell membrane electrode, wherein the hydrogen electrode is a NiO-BaCe alloy with a mass ratio of 6:4. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 The composite material has a hydrogen electrode with a porosity of 40% and an electrolyte layer consisting of BaCe at a molar ratio of 1:5. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 With BaZr 0.8 Y 0.1 Yb 0.1 O 2.9 The mixture is composed of Sm and Sm, with the oxygen electrode being a 5:5 mass ratio. 0.5 Sr 0.5 CoO 2.6 -BaZr 0.8 Y 0.2 O 2.9 The composite material has an oxygen electrode porosity of 40%. The hydrogen electrode and electrolyte layer are co-fired at 1380℃ to achieve an electrolyte density of 95%, and the oxygen electrode is sintered at 1000℃.

[0030] The membrane electrode operates in steam electrolysis mode, and at an electrolysis voltage of 1.3V and an operating temperature of 600℃, the electrolysis current density reaches -0.37 A / cm². 2 .

[0031] Example 1

[0032] A solid oxide electrolytic cell membrane electrode comprises a hydrogen electrode, an oxygen electrode, and an electrolyte layer located between the hydrogen and oxygen electrodes. The hydrogen electrode is a NiO-BaCe electrolyte with a mass ratio of 6:4. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 The composite material has a hydrogen electrode porosity of 40%, and the electrolyte layer connected to the hydrogen electrode is a 10-micrometer-thick BaCe layer. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 BaZr with a thickness of 2 micrometers 0.8 Y 0.1 Yb 0.1 O 2.9 with BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 The hydrogen electrode and electrolyte layer are connected, and the co-firing temperature is 1280℃, with an electrolyte density of 98%. The oxygen electrode is a 5:5 mass ratio of Sm... 0.5 Sr 0.5 CoO 2.6 -BaZr 0.8 Y 0.2 O 2.9 The composite material involves coating an oxygen electrode onto a co-fired electrolyte layer and sintering it at a temperature of 1000℃. The oxygen electrode has a porosity of 40%.

[0033] The membrane electrode operates in steam electrolysis mode, and at an electrolysis voltage of 1.3V and an operating temperature of 600℃, the electrolysis current density reaches -2.2A / cm². 2 In the mode of electrolyzing water vapor and carbon dioxide (volume ratio 50:50), with an electrolysis voltage of 1.3V and an operating temperature of 600℃, the electrolysis current density reaches -2.8A / cm³. 2 Compared with the comparative example, the membrane electrode structure of this application effectively reduces the co-firing temperature of the hydrogen electrode-electrolyte, resulting in a good electrode / electrolyte interface, increased three-phase interface density, and maintained good electrochemical performance.

[0034] Example 2

[0035] A solid oxide electrolytic cell membrane electrode comprises a hydrogen electrode, an oxygen electrode, and an electrolyte layer located between the hydrogen and oxygen electrodes. The hydrogen electrode is a NiO-BaCe electrolyte with a mass ratio of 6:4. 0.7 Zr 0.1 Y 0.1 Yb0.1 O 2.55 The composite material has a hydrogen electrode porosity of 40%, and the electrolyte layer connected to the hydrogen electrode is a 10-micrometer-thick BaCe layer. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 2-micron BaZr 0.7 Ce 0.1 Y 0.1 Yb 0.1 O 2.9 Layers and BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 The layers are connected, with the hydrogen electrode and electrolyte layer co-fired at 1300℃, and the electrolyte density is 98%. The oxygen electrode is a 5:5 mass ratio of Sm... 0.5 Sr 0.5 CoO 2.6 -BaZr 0.8 Y 0.2 O 2.9 The composite material involves coating an oxygen electrode onto a co-fired electrolyte layer and sintering it at a temperature of 1000℃. The oxygen electrode has a porosity of 40%.

[0036] The membrane electrode operates in steam electrolysis mode, and at an electrolysis voltage of 1.3V and an operating temperature of 600℃, the electrolysis current density reaches -1.95 A / cm². 2 .

[0037] Example 3

[0038] A solid oxide electrolytic cell membrane electrode comprises a hydrogen electrode, an oxygen electrode, and an electrolyte layer located between the hydrogen and oxygen electrodes. The hydrogen electrode is a NiO-BaCe electrolyte with a mass ratio of 6:4. 0.4 Zr 0.3 Y 0.2 Yb 0.1 O 2.55 The composite material has a hydrogen electrode porosity of 40%, and the electrolyte layer connected to the hydrogen electrode is a 10-micrometer-thick BaCe layer. 0.4 Zr 0.3 Y 0.2 Yb 0.1 O 2.55 2-micron BaZr 0.7 Ce 0.1 Y 0.1 Yb 0.1 O 2.9 Layers and BaCe 0.4 Zr 0.3 Y0.2 Yb 0.1 O 2.55 The layers are connected, with the hydrogen electrode and electrolyte layer co-fired at 1280℃, and the electrolyte density is 98%. The oxygen electrode is a 5:5 mass ratio of Sm... 0.5 Sr 0.5 CoO 2.6 -BaZr 0.8 Y 0.2 O 2.9 The composite material involves coating an oxygen electrode onto a co-fired electrolyte layer and sintering it at a temperature of 1000℃. The oxygen electrode has a porosity of 40%.

[0039] The membrane electrode operates in steam electrolysis mode, and at an electrolysis voltage of 1.3V and an operating temperature of 600℃, the electrolysis current density reaches -1.83 A / cm². 2 .

[0040] Example 4

[0041] A solid oxide electrolytic cell membrane electrode comprises a hydrogen electrode, an oxygen electrode, and an electrolyte layer located between the hydrogen and oxygen electrodes. The hydrogen electrode is a NiO-BaCe electrolyte with a mass ratio of 6:4. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 The composite material has a hydrogen electrode porosity of 40%, and the electrolyte layer connected to the hydrogen electrode is a 2-micrometer-thick BaCe layer. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 10-micron BaZr 0.8 Y 0.1 Yb 0.1 O 2.9 Layers and BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 2.55 The layers are connected, with the hydrogen electrode and electrolyte layer co-fired at 1280℃, and the electrolyte density is 98%. The oxygen electrode is a 5:5 mass ratio of Sm... 0.5 Sr 0.5 CoO 2.6 -BaZr 0.8 Y 0.2 O 2.9 The composite material involves coating an oxygen electrode onto a co-fired electrolyte layer and sintering it at a temperature of 1000℃. The oxygen electrode has a porosity of 40%.

[0042] The membrane electrode operates in steam electrolysis mode, and at an electrolysis voltage of 1.3V and an operating temperature of 600℃, the electrolysis current density reaches -1.33 A / cm². 2 .

Claims

1. A solid oxide electrolysis cell membrane electrode characterized by: The membrane electrode is composed of a hydrogen electrode, an oxygen electrode, and an electrolyte layer between the hydrogen electrode and the oxygen electrode; the hydrogen electrode is a metal-proton conductive composite material, the oxygen electrode is a proton-electron-oxygen ion conductive composite material, the electrolyte layer includes BaCe 1-x-y Zr x M y O 3-ε layer and BaZr 1-m-n Ce m M n O 3-δ layer, the BaCe 1-x-y Zr x M y O 3-ε layer is connected with the hydrogen electrode, the BaCe 1-x-y Zr x M y O 3-ε layer is connected with the BaZr 1-m-n Ce m M n O 3-δ layer, the BaZr 1-m-n Ce m M n O 3-δ layer is connected with the oxygen electrode; the BaCe 1-x-y Zr x M y O 3-ε layer and the BaZr 1-m-n Ce m M n O 3-δ layer are uniformly distributed in the electrolyte layer; the uniform distribution means that the BaCe 1-x-y Zr x M y O 3-ε layer and the BaZr 1-m-n Ce m M n O 3-δ layer are composed of electrolyte, co-sintered, in the co-sintering, the BaCe 1-x-y Zr x M y O 3-ε layer and the BaZr 1-m- n Ce m M n O 3-δ layer are reaction sintered to form a dense electrolyte layer with uniform distribution of components; the co-sintering temperature is 1200-1350℃; wherein 0≤x≤0.3, 0 1-x-y Zr x M y O 3-ε and the M element in the BaZr 1-m-n Ce m M n O 3-δ remains the same.

2. A solid oxide electrolysis cell membrane electrode according to claim 1, characterised in that: The hydrogen electrode has a porous structure and a porosity of 35-50%; the oxygen electrode has a porous structure and a porosity of 30-45%; and the electrolyte has a density of 95-100%.

3. The solid oxide electrolysis cell membrane electrode of claim 1, wherein: BaCe 1-x-y Zr x M y O 3-ε layer and BaZr 1-m-n Ce m M n O 3-δ layer are 1 to 10 micrometers.

4. The solid oxide electrolysis cell membrane electrode of claim 1, wherein: BaCe 1-x-y Zr x M y O 3-ε layer and BaZr 1-m-n Ce m M n O 3-δ layer are 1 to 5 micrometers.

5. The solid oxide electrolysis cell membrane electrode of claim 1, wherein: BaCe 1-x- y Zr x M y O 3-ε wherein x is 0.1 < x < 0.2 and y is 0.05 < y < 0.2, and the BaZr 1-m-n Ce m M n O 3-δ wherein m is 0.1 < m < 0.2 and n is 0.05 < n < 0.

2.

6. The solid oxide electrolysis cell membrane electrode of claim 1, wherein: The metal-proton conductive composite material comprises a composite material of metal Ni or metal Cu and a perovskite proton conductor; and the proton-electron-oxygen ion conductive composite material comprises a composite material of a perovskite oxide or a perovskite proton conductor with proton-electron-oxygen ion conductivity and a perovskite electron-oxygen ion mixed conductor.

7. The method of producing a solid oxide electrolysis cell membrane electrode according to any one of claims 1 to 6, characterized in that: The method comprises: BaCe 1-x-y Zr x M y O 3-ε layer and BaZr 1-m-n Ce m M n O 3-δ layer constitutes an electrolyte, the BaCe 1-x-y Zr x M y O 3-ε layer is connected with a hydrogen electrode, the BaCe 1-x-y Zr x M y O 3-ε layer is connected with a BaZr 1-m-n Ce m M n O 3-δ layer, co-sintering, in the co-sintering, the BaCe 1-x- y Zr x M y O 3-ε layer and BaZr 1-m-n Ce m M n O 3-δ layer is reaction-sintered to form a dense electrolyte layer with uniform distribution of components, and then the BaZr 1-m-n Ce m M n O 3-δ layer is coated with an oxygen electrode on the surface, and the oxygen electrode is sintered again to obtain a membrane electrode.

8. The method of claim 7, wherein: The temperature of the co-sintering is 1200-1350 DEG C, and the temperature of the sintered oxygen electrode is 800-1100 DEG C.

9. Use of a solid oxide electrolysis cell membrane electrode according to any one of claims 1 to 6 or a solid oxide electrolysis cell membrane electrode produced by the production method according to claim 7 or 8, characterized in that: The membrane electrode is applied to electrolysis of water vapor to produce hydrogen, electrolysis of carbon dioxide to produce carbon monoxide, or electrolysis of water vapor and carbon dioxide to produce synthetic gas.

10. Use according to claim 9, characterized in that: The membrane electrode is suitable for an electric pile equipped with a flat plate type, a tube type or a flat tube type structure.

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