Solid oxide electrolytic cell with an air-side electrode resistant to electrolysis

Abstract

To provide a solid oxide electrolyzer cell (SOEC) with an electrolysis-tolerant air-side electrode.SOLUTION: A solid oxide electrolyzer cell (SOEC) includes a solid oxide electrolyte, a fuel-side electrode disposed on a fuel side of the electrolyte, and an air-side electrode disposed on an air side of the electrolyte. The air-side electrode includes a barrier layer disposed on the air side of the electrolyte and including a first doped ceria material, and a functional layer disposed on the barrier layer and including an electrically conductive material and a second doped ceria material.SELECTED DRAWING: None

Description

【Technical Field】 【0001】 The present disclosure generally relates to solid oxide electrolyzer cells, and more particularly to electrolyzer cells having an air-side electrode resistant to electrolysis. 【Background Art】 【0002】 A solid oxide reversible fuel cell (SORFC) system can operate in a fuel cell mode to generate electricity by oxidizing a fuel. The SORFC system can also operate in an electrolysis mode to generate hydrogen by electrolyzing water. However, conventional SORFCs can suffer degradation of the air-side electrode due to an increase in cell voltage that can occur during the electrolysis process. 【Summary of the Invention】 【0003】 According to various embodiments, a solid oxide electrolyzer cell (SOEC) includes a solid oxide electrolyte, a fuel-side electrode disposed on the fuel side of the electrolyte, and an air-side electrode disposed on the air side of the electrolyte. The air-side electrode is disposed on the air side of the electrolyte and has a barrier layer containing a first doped ceria material, and a functional layer disposed on the barrier layer and containing a conductive material and a second doped ceria material. 【Brief Description of the Drawings】 【0004】 [Figure 1A] FIG. 1A is a perspective view of an SOEC stack according to various embodiments of the present disclosure. [Figure 1B] FIG. 1B is a cross-sectional view of a portion of the stack of FIG. 1A. [Figure 2A] FIG. 2A is a plan view of the air side of an interconnect according to various embodiments of the present disclosure. [Figure 2B] FIG. 2B is a plan view of the fuel side of the interconnect of FIG. 2A. [Figure 3A] FIG. 3A is a plan view of the air side of an SOEC cell according to various embodiments of the present disclosure. [Figure 3B]Figure 3B is a plan view of the fuel side of the SOEC cell shown in Figure 3A. [Figure 4] Figure 4 is a photograph showing delamination of the air electrode. [Figure 5] Figure 5 is a cross-sectional view of an SOEC stack having electrolysis-resistant SOEC cells according to various embodiments of the present disclosure. [Figure 6A] Figure 6A is a chart showing the degradation rate of the air electrode of an SOEC cell according to various embodiments of this disclosure. [Figure 6B] Figure 6B is a chart showing the degradation rate of the comparative SOEC cell. [Modes for carrying out the invention] 【0005】 Various embodiments will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. References to specific examples and embodiments are for illustrative purposes only and are not intended to limit the scope of the invention or the claims. 【0006】 When an element or layer is referred to as "on top of" or "connected to" another element or layer, it will be understood that the element or layer may be directly on top of or directly connected to another element or layer, or that there may be an intervening element or layer. In contrast, when an element is referred to as "directly on top of" or "directly connected to" another element or layer, there is no intervening element or layer. For the purposes of this disclosure, it will be understood that "at least one of X, Y, and Z" may be interpreted as X only, Y only, Z only, or any combination of two or more items of X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ). 【0007】 Where a range of values ​​is presented, unless the context clearly indicates otherwise, each value between the upper and lower limits of that range, up to the first decimal place of the lower limit unit, and any other stated or intervening values ​​within that stated range are understood to be included in the present invention. The upper and lower limits of these smaller ranges may be independently contained within these smaller ranges and are included in the present invention, depending on any limit values ​​specifically excluded within the stated range. Where a stated range includes one or both of the limit values, a range excluding one or both of these included limit values ​​is also included in the present invention. It will also be understood that the term “about” may refer to a minor measurement error, for example, 5% to 10%. Furthermore, as used herein, weight percent (W%) and atomic percent (Atomic%) refer to a percentage of the total weight or total number of atoms of the corresponding composition, respectively. 【0008】 Words such as "then," "next," and "then" are not necessarily intended to limit the order of the process, and these words may be used to guide the reader through the description of the method. Furthermore, any singular reference to a claim element using, for example, the article "a," "an," or "the" should not be interpreted as limiting that element to the singular form. 【0009】 As used herein, the term “electrolytic cell stack” means a stack of multiple electrolytic cell cells that can optionally share a common water inlet and exhaust passage or riser. As used herein, an “electrolytic cell stack” comprises a separate electrical entity having two end plates that are directly connected to the stack’s power regulator and power (i.e., electrical) input, or constitutes part of an electrolytic cell column having terminal boards that provide electrical input. 【0010】 Figure 1A is a perspective view of an electrolytic cell stack 100 according to various embodiments of the present disclosure, and Figure 1B is a partial cross-sectional view of a stack 100 according to various embodiments of the present disclosure. Referring to Figures 1A and 1B, the stack 100 can be a solid oxide electrolytic cell (SOEC) stack having solid oxide electrolytic cells 1 separated by an interconnect 10. Referring to Figure 1B, each electrolytic cell 1 has an air-side electrode 3, a solid oxide electrolyte 5, and a fuel-side electrode 7. 【0011】 Electrolytic cell stacks are often assembled from a very large number of electrolytic cell cells 1 of planar elements, tubes, or other shapes. Although the electrolytic cell stack 100 in Figure 1A is arranged vertically, electrolytic cell stacks can also be arranged horizontally or in any other direction. For example, water can be supplied through water conduits 22 (e.g., water riser openings) formed in each interconnect 10 and electrolytic cell 1, and oxygen can be supplied from the sides of the stack between the air-side ribs of the interconnect 10. 【0012】 Each interconnect 10 electrically connects adjacent electrolytic cell 1 within the stack 100. In particular, an interconnect 10 can electrically connect the fuel-side electrode 7 of one electrolytic cell 1 to the air-side electrode 3 of an adjacent electrolytic cell 1. Figure 1B shows that the lower electrolytic cell 1 is located between two interconnects 10. A Ni mesh (not shown) can be used to electrically connect the interconnect 10 to the fuel-side electrode 7 of an adjacent electrolytic cell 1. 【0013】 Each interconnect 10 has a fuel-side rib 12A that at least partially defines a fuel channel 8A and an air-side rib 12B that at least partially defines an oxidizer (e.g., air) channel 8B. The interconnect 10 can function as a separator, separating water flowing to the fuel-side electrode of one cell 1 in the stack from oxygen flowing from the air-side electrode of an adjacent cell 1 in the stack. An air end plate or a fuel end plate (not shown) may be present at either end of the stack 100. 【0014】 Each interconnect 10 can be formed from or contain a conductive material such as a metal alloy (e.g., chromium-iron alloy) having a coefficient of thermal expansion similar to that of the solid oxide electrolyte in the cell (e.g., a difference of 0% to 10%). For example, the interconnect 10 can contain a metal (e.g., a chromium-iron alloy containing 4% to 6% by weight iron (e.g., 5% by weight iron) and optionally 1% or less by weight yttrium, with the remainder being chromium), and can electrically connect the fuel-side electrode 7 of one electrolytic cell 1 to the air-side electrode 3 of an adjacent electrolytic cell 1. 【0015】 Figure 2A is a top view of the air side of interconnect 10 according to various embodiments of the present disclosure, and Figure 2B is a top view of the fuel side of interconnect 10 according to various embodiments of the present disclosure. Referring to Figures 1B and 2A, the air side comprises air channels 8B extending from opposing first and second edges of interconnect 10. Oxygen flows from the air-side electrode 3 of the adjacent electrolytic cell 1 through the air channels 8B. A ring seal 20 surrounds the fuel holes 22A and 22B of interconnect 10 to prevent water from coming into contact with the air-side electrode 3. A strip-shaped peripheral seal 24 is located in the peripheral portion of the air side of interconnect 10. Seals 20 and 24 can be formed of glass or glass-ceramic material. The peripheral portion may be a raised platform without ribs or channels. The surface of the peripheral region may be coplanar with the top of the rib 12B. 【0016】 Referring to Figures 1B and 2B, the fuel side of the interconnect 10 may have a fuel channel 8A and a fuel manifold 28. Water flows from one of the fuel holes 22A (for example, an inlet fuel hole forming part of the fuel inlet riser) into the adjacent manifold 28, through the fuel channel 8A, and to the fuel-side electrode 7 of the adjacent electrolytic cell 1. Excess water can flow into the other fuel manifold 28 and then into the outlet fuel hole 22B. A flame seal 26 is positioned in the peripheral region of the fuel side of the interconnect 10. The peripheral region may be a raised platform that does not include ribs or channels. The surface of the peripheral region may be coplanar with the top of the rib 12A. 【0017】 Figure 3A is a plan view of the air side of an electrolytic cell 1 according to various embodiments of the present disclosure, and Figure 3B is a plan view of the fuel side of an electrolytic cell 1 according to various embodiments of the present disclosure. Referring to Figures 1A, 2A, 3A, and 3B, the electrolytic cell 1 may have an inlet fuel port 22A, an outlet fuel port 22B, an electrolyte 5, and an air-side electrode 3. The air-side electrode 3 may be located on the air side of the electrolyte 5. The fuel-side electrode 7 may be located on the fuel (e.g., water) side opposite the electrolyte 5. 【0018】 The fuel holes 22A and 22B can extend through the electrolyte 5 and can be positioned to overlap with the fuel holes 22A and 22B of the interconnect 10 when assembled in the electrolytic cell stack 100. The air-side electrode 3 can be printed on the electrolyte 5 so as not to overlap with the ring seal 20 and peripheral seal 24 when assembled in the electrolytic cell stack 100. The fuel-side electrode 7 can have a similar shape to the air-side electrode 3. The fuel-side electrode 7 can be positioned so as not to overlap with the frame seal 26 when assembled in the stack 100. In other words, electrodes 3 and 7 can be set back from the edges of the electrolyte 5 so that the corresponding edge regions of the electrolyte 5 can directly contact the corresponding seals 20, 24, and 26. 【0019】 In one embodiment, the electrolytic cell stack 100 can operate only in electrolysis mode. Therefore, the electrolytic cell stack 100 does not operate in fuel cell mode to generate electricity from the fuel and air supplied to the fuel-side electrode and the air-side electrode, respectively. Alternatively, the electrolytic cell stack 100 may have a solid oxide regenerative (i.e., reversible) fuel cell (SORFC) stack. The SORFC can operate in fuel cell (FC) mode (e.g., power generation mode) to generate electricity from the fuel and air supplied to the fuel-side electrode and the air-side electrode, respectively, and can operate in electrolytic cell (EC) mode (e.g., electrolysis mode) to produce hydrogen and oxygen from water supplied to the fuel-side electrode 7. In FC mode, oxygen ions are carried from the air-side (e.g., cathode) electrode 3 of the SORFC to the fuel-side (e.g., anode) electrode 7, oxidizing the fuel (e.g., hydrocarbon fuel such as hydrogen and / or natural gas) to generate electricity. In EC mode, a positive potential is applied to the air side of the cell, and oxygen ions are transported from the water at the fuel-side electrode 7 through the electrolyte 5 to the air-side electrode 3. As a result, the water is electrolyzed into hydrogen at the fuel-side electrode 7 and into oxygen at the air-side electrode 3. 【0020】 The air-side electrode 3 and fuel-side electrode 7 of the SORFC operate as a cathode and anode, respectively, during FC mode, and as an anode and cathode, respectively, during EC mode (i.e., the cathode in FC mode is the anode in EC mode, and the anode in FC mode is the cathode in EC mode). Therefore, it can be said that the SORFC described herein has an air-side electrode and a fuel-side electrode. 【0021】 During EC mode, water in the fuel flow is reduced (H2O + 2e → O 2- +H2), H2 gas and O 2- Ions are formed, and this O 2- Ions are transported through the solid electrolyte and then oxidized at the air-side electrode (O 2-Oxygen molecules are produced (by oxidation to O2). The open-circuit voltage of a SORFC operating with air and moist fuel (e.g., hydrogen and / or reformed natural gas) can be approximately 0.9V to 1.0V (depending on moisture content), so a positive voltage applied to the air-side electrode in EC mode raises the cell voltage to the normal operating voltage of approximately 1.1V to 1.3V. In constant-current mode, if there is cell degradation, the cell voltage may increase over time, and cell degradation can be due to both ohmic sources and electrode polarization. 【0022】 One of the major hurdles faced by current-generation solid oxide electrolytic cells and SORFCs is delamination of the air electrode at high current densities. The degree of delamination increases with current density and the transport flux of oxide ions. While we do not wish to be bound by any particular theory, it is thought that delamination may be caused by the deposition of oxygen at the electrolyte / cathode interface, which may lead to high pressure and delamination of the air electrode. 【0023】 Figure 4 is a photograph showing delamination of the air electrode 3 after operating a solid oxide electrolytic cell in electrolysis mode for a long period of time at a high current density. As shown in Figure 4, the air-side electrode 3 may separate from the underlying electrolyte 5, as indicated by the black region between them. 【0024】 Figure 5 is a cross-sectional view of an electrolytic cell stack 500 having an electrolysis-resistant solid oxide electrolytic cell 502 according to various embodiments of the present disclosure. Since the electrolytic cell stack 500 is similar to the stack 100 in Figures 1A to 3B, only the differences from the stack 100 will be described in detail. 【0025】 Referring to FIG. 5, the electrolytic cell stack 500 can have at least one electrolytic cell 502 disposed between interconnects 10. The electrolytic cell 502 can operate only in the electrolysis mode (e.g., the cell can have a solid oxide electrolytic cell (SOEC)), or can operate in both the fuel cell mode and the electrolysis mode (e.g., the electrolytic cell 502 can have a SORFC). The electrolytic cell 502 has a solid oxide electrolyte 5, an air-side electrode 3 disposed on the air side of the electrolyte 5, and a fuel-side electrode 7 disposed on the fuel side of the electrolyte 5. In the fuel cell mode, air can be supplied to the air-side electrode 3 by the air channel 8B, and in the fuel cell mode, fuel can be supplied to the fuel-side electrode 7 by the fuel channel 8A. On the other hand, in the electrolysis mode, water can be supplied to the fuel-side electrode 7 by the fuel channel 8A. 【0026】 Various materials can be used for the solid oxide electrolyte 5, the fuel-side electrode 7, and the air-side electrode 3. In various embodiments, the electrolyte 5 can include an ion-conductive material or an ion-conductive phase, such as stabilized zirconia, such as scandia-stabilized zirconia (SSZ), yttria-stabilized zirconia (YSZ), scandia-ceria-stabilized zirconia (SCSZ), scandia-ceria-yttria-stabilized zirconia (SCYSZ), scandia-ceria-ytterbia-stabilized zirconia (SCYbSZ), etc. Alternatively, the electrolyte 5 can include another ion-conductive material, such as doped ceria, such as samaria-doped ceria (SDC), gadolinia-doped ceria (GDC), or yttria-doped ceria (YDC), etc. In some embodiments, the electrolyte 5 can include a material represented by the formula: (ZrO2) 1-w-x-z (Sc2O3) w (CeO2) x (Y2O3) a (Yb2O3) b (where 0.09 ≦ w ≦ 0.11, 0 < x ≦ 0.0125, a + b = z, 0.0025 ≦ z ≦ 0.0125). In some embodiments, the electrolyte 5 is (ZrO2) 0.88 (Sc2O3)0.1 (CeO2) 0.01 (Yb2O3) 0.01 or (ZrO2) 0.88 (Sc2O3) 0.1 (CeO2) 0.01 (Y2O3) 0.01 It may include (ZrO2). Alternatively, electrolyte 5 is (ZrO2) 0.89 (Sc2O3) 0.1 (CeO2) 0.01 It can include... 【0027】 The fuel-side electrode 7 may have a cermet layer comprising a metal-containing phase and a ceramic phase. The metal-containing phase may include a metal catalyst, such as nickel (Ni), cobalt (Co), copper (Cu), or alloys thereof, and acts as an electron conductor. The metal catalyst may be in a metallic state or an oxide state. For example, when the metal catalyst is in an oxidized state, it forms a metal oxide. Therefore, the fuel-side electrode 7 can be annealed in a reducing atmosphere before operation of the electrolytic cell 1 to reduce the oxidized metal catalyst back to a metallic state. 【0028】 The metal-containing phase can consist solely of nickel in a reduced state. When this nickel-containing phase is in an oxidized state, it can form nickel oxide. Therefore, it is preferable to anneal the fuel-side electrode 7 in a reducing atmosphere before operation to reduce nickel oxide back to nickel. 【0029】 The ceramic phase of the fuel-side electrode 7 may include, but is not limited to, gadolinia-doped ceria (GDC), samaria-doped ceria (SDC), ytterbia-doped ceria (YDC), scandia-stabilized zirconia (SSZ), ytterbia-ceria-scandia-stabilized zirconia (YbCSSZ), etc. As disclosed in U.S. Patent No. 8,580,456 incorporated herein by reference, in YbCSSZ, scandia may be present in an amount corresponding to 9 mol% to 11 mol%, for example 10 mol%, ceria may be present in an amount greater than 0 mol% (e.g., at least 0.5 mol%) and 2.5 mol% or less, for example 1 mol%, and at least one of yttria and ytterbia may be present in an amount greater than 0 mol% and 2.5 mol% or less, for example 1 mol%. 【0030】 Furthermore, if necessary, additional contact layers or current collector layers can be placed on the fuel-side electrode 7. For example, a Ni or nickel oxide anode contact layer can be formed on the fuel-side electrode 7. 【0031】 The air-side electrode 3 may have a barrier layer 30 directly placed on the air side of the electrolyte 5, a functional layer 32 placed on the barrier layer 30, and an arbitrary current collector layer 34 placed on the functional layer 32. Therefore, the functional layer 32 is located between the barrier layer 30 and the current collector layer 34. 【0032】 The barrier layer 30 can be sintered on the air side of the electrolyte 5. The barrier layer 30 may contain doped ceria material, consist essentially of doped ceria material, or consist of doped ceria material. For example, the barrier layer may contain about 95% by weight (Wt%) to about 100% by weight of doped ceria material relative to the total weight of the barrier layer 30. The doped ceria material may include samarium-doped ceria (SDC) and / or gadolinium-doped ceria (GDC). 【0033】 SDC is based on the formula: Ce 1-x Sm x O 2-d(where x is in the range of 0.1 to 0.3) can be expressed as follows: For example, a certain SDC material can be expressed by the formula: Ce 0.8 Sm 0.2 O 2-d Ce 0.9 Sm 0.1 O 2-d and Ce 0.7 Sm 0.3 O 2-d This can be expressed as follows: (where d is in the range of 0 to 0.2, for example, 0 to 0.1). 【0034】 GDC is the formula Ce 1-x Gd x O 2-d (In the formula, x is in the range of 0.1 to 0.3, and d is in the range of 0 to 0.2, for example, 0 to 0.1). For example, a certain GDC material can be expressed by formula: Ce 0.9 Gd 0.1 O 2-d Ce 0.8 Gd 0.2 O 2-d and Ce 0.7 Gd 0.3 O 2-d This can be expressed as follows: (where d is in the range of 0 to 0.2, for example, 0 to 0.1). 【0035】 The functional layer 32 may include a mixture of a conductive material and a doped ceria material. The conductive material is a conductive perovskite material, for example, lanthanum strontium manganite (LSM), lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium cobaltite (LSC), lanthanum strontium cobalt manganite (LSCM), lanthanum strontium ferrite (LSF), La 0.85 Sr 0.15 Cr 0.9 Ni 0.1This may include O3(LSCN), combinations thereof, etc. In some embodiments, the conductive material may preferably include LSM and / or LSCF. Alternatively, the conductive material may include a metal such as platinum. For example, the functional layer 32 may include about 10% to about 90% by weight of the above-mentioned conductive material and about 10% to about 90% by weight of doped ceria material. 【0036】 In various embodiments, the functional layer may include LSM as a conductive material. LSM is given by formula: (La 1-z Sr z ) q MnO 3-d (In the formula, z is in the range of 0.1 to 0.4, q is in the range of 0.94 to 1, for example, 0.96 to 1, and d is in the range of 0 to 0.2) can be expressed as follows. For example, LSM is La 0.8 Sr 0.2 MnO 3-d , or (La 0.8 Sr 0.2 ) 0.98 MnO 3-d This may include A-site missing LSMs such as (where d is in the range of 0 to 0.1). 【0037】 In some embodiments, the functional layer may include LSCF as the conductive material. LSCF is given by formula: (La x Sr 1-x ) y Co z Fe 1-z O 3-δ (In the formula, x is in the range of 0.4 to 0.8, y is in the range of 0.94 to 1.0, z is in the range of 0.01 to 0.99, and δ is an equilibrium oxygen deficiency in the range of 0 to 0.1) can be expressed as follows. For example, LSCF is La 0.58 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ , (La 0.6 Sr 0.4 ) 0.98 Co 0.2 Fe 0.8 O 3-δ or (La 0.6Sr 0.4 ) 0.95 Co 0.2 Fe 0.8 O 3-δ The formula may include (where δ represents an equilibrium oxygen deficiency). 【0038】 The barrier layer 30 and the functional layer 32 may contain the same doped ceria material or different doped ceria materials. For example, the barrier layer 30 may contain GDC, and the functional layer 32 may contain LSM and GDC, or LSM and SDC. In another embodiment, the barrier layer 30 may contain SDC, and the functional layer 32 may contain LSM and SDC, or LSM and GDC. In yet another embodiment, the barrier layer may contain SDC, and the functional layer may contain LSCF and SDC, or LSCF and GDC. 【0039】 While we do not wish to be bound by any particular theory, it is thought that the mixed oxide ions and electron conduction of the ceria phase in the barrier layer 30 reduce the overpotential at the interface between the barrier layer 30 and the functional layer 32. This reduction in overpotential can suppress delamination of the air-side electrode 3 from the electrolyte 5. 【0040】 The current collector layer 34 may include conductive materials such as conductive metal oxides like LSM. However, other conductive perovskites, such as LSC, LSCM, LSCF, LSF, LSCN, etc., or metals such as Pt can also be used. 【0041】 Figure 6A is a chart showing the voltage changes of SOEC cells in a first embodiment and SOEC cells in a second embodiment between the start of life and 17 current cycles in an SOEC stack of a certain embodiment. Figure 6B is a chart showing the voltage changes of comparative SOEC cells between the start of life and 17 current cycles in a comparative SOEC stack under similar conditions. In both figures, the y-axis represents the voltage change in volts, and the x-axis represents the number of SOEC cells in each stack. 【0042】 Referring to Figures 6A and 6B, the SOEC cell of the first embodiment has an SDC barrier layer 30 and a GDC / LSM cathode functional layer 32, while the SOEC cell of the second embodiment has an SDC barrier layer 30 and an SDC / LSM cathode functional layer 32, except that the SOEC cell of the first embodiment has an SDC barrier layer 30 and an SDC / LSM cathode functional layer 32. The comparative SOEC cell does not have a barrier layer 30 and has a cathode functional layer including YSZ / LSM. 【0043】 Referring to Figures 6A and 6B, a larger cell voltage difference indicates a higher cell overpotential and, consequently, greater cathode degradation. As can be seen from the chart, the comparative SOEC cell exhibits a larger cell voltage difference (and thus an increase in cell overpotential), while the cell of this embodiment exhibits a substantially smaller cell voltage difference. Therefore, the doped ceria barrier layer and cathode functional layer material are expected to provide unexpectedly improved protection against cell overpotential, thereby reducing delamination and / or general cathode degradation. 【0044】 While the above describes particularly preferred embodiments, it will be understood that the present invention is not limited thereto. Those skilled in the art will notice that various modifications can be made to the disclosed embodiments, and that such modifications are intended to be within the scope of the present invention. All publications, patent applications and patents cited herein are incorporated herein by reference in their entirety.

Claims

[Claim 1] A solid oxide electrolyte represented by the formula: (ZrO₂) 1-w-x-z (Sc₂O₃) w (CeO₂) x (Y₂O₃) a (Yb₂O₃) b (wherein 0.09≦w≦0.11, 0<x≦0.0125, a+b=z, 0.0025≦z≦0.0125), The fuel-side electrode is positioned on the fuel side of the electrolyte, The air-side electrode is positioned on the air side of the electrolyte, A solid oxide electrolytic cell (SOEC) having, wherein the air-side electrode is Displaced on the air side of the electrolyte, a barrier layer comprising a first doped ceria material, which includes a first samarium-doped ceria (SDC) material, A functional layer is disposed on the barrier layer and comprises a conductive material and a second samarium-doped ceria material. A conductive perovskite current collector layer is disposed on the air side of the functional layer opposite the barrier layer, It has, The conductive material of the functional layer is of formula (La ｘ Sr １－ｘ ) ｙ Co ｚ Fe １－ｚ O ３－δ It contains lanthanum strontium cobalt ferrite (LSCF) represented by the formula (wherein x is in the range of 0.4 to 0.8, y is in the range of 0.94 to 1.0, z is in the range of 0.01 to 0.99, and δ is an equilibrium oxygen deficiency in the range of 0 to 0.1), wherein the second SDC material is of the formula Ce １－ｘ Sm ｘ O ２－ｄ (where x ranges from 0.1 to 0.3 and d ranges from 0 to 0.2), The aforementioned solid oxide electrolytic cell (SOEC). [Claim 2] The first SDC material is, １－ｘ Sm ｘ O ２－ｄ (In the formula, x is in the range of 0.1 to 0.3, and d is in the range of 0 to 0.2) The solid electrolyte is represented by the formula: (ZrO₂) 0.88 (Sc₂O₃) 0.1 (CeO₂) 0.01 (Yb₂O₃) 0.01, or the formula: (ZrO₂) 0.88 (Sc₂O₃) 0.1 (CeO₂) 0.01 (Y₂O₃) 0.01 SOEC as described in claim 1. [Claim 3] The first SDC material is Ce ０．８ Sm ０．２ O ２－ｄ Ce ０．９ Sm ０．１ O ２－ｄ or Ce ０．７ Sm ０．３ O ２－ｄ SOEC according to claim 2, comprising (wherein d is in the range of 0 to 0.1). [Claim 4] SOEC according to claim 1, wherein the conductive perovskite current collector layer comprises lanthanum strontium manganite (LSM), lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium cobalt manganite (LSCM), lanthanum strontium ferrite (LSF), or lanthanum strontium nickel chromite (LSCN). [Claim 5] The LSCF is La ０．５８ Sr ０．４ Co ０．２ Fe ０．８ O ３－δ SOEC according to claim 1, including the SOEC described in claim 1. [Claim 6] The aforementioned L SCF is (La ０．６ Sr ０．４ ) ０．９８ Co ０．２ Fe ０．８ O ３－δ SOEC according to claim 1, including the SOEC described in claim 1. [Claim 7] The aforementioned L SCF is (La ０．６ Sr ０．４ ) ０．９５ Co ０．２ Fe ０．８ O ３－δ SOEC according to claim 1, including the SOEC described in claim 1. [Claim 8] The SOEC according to claim 4, wherein the conductive perovskite current collector layer comprises the lanthanum strontium cobalt ferrite (LSCF).

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