An SFM-based fuel electrode, a solid oxide electrolysis cell comprising the same, and a method of preparing the same

Abstract

This invention relates to an SFM-based fuel electrode, a solid oxide electrolyzer containing the same, and a method for preparing the same, comprising a perovskite matrix, wherein the perovskite matrix is ​​Sr₂Fe₂ doped at the B' site using Sc. 1.5 Mo 0.5 O 6‑δ The perovskite matrix is ​​optionally incorporating Ni at the B-site and / or supported with a YCoO3 second phase, wherein Y is selected from one or more of Pr, Nd, Sm, Eu, and Gd. This invention, by employing Sc to dope SFM-based perovskites at the B' site and selectively introducing Ni at the B-site and supporting a specific rare-earth cobaltate second phase, effectively enhances the oxygen vacancy concentration and ion transport capacity of the material, significantly accelerates the CO2 electrocatalytic reaction kinetics, and improves electrolysis activity under medium and low temperature conditions.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide electrolyzers (SOECs) technology, and more specifically relates to an SFM-based fuel electrode, a solid oxide electrolyzer containing the same, and a method for preparing the same. Background Technology

[0002] Solid oxide electrolyzers (SOECs) can efficiently electrolyze CO2 and H2O into syngas (CO+H2) under high-temperature conditions, showing significant application potential in carbon neutrality and related technological pathways. The fuel electrode is a core component of SOECs, requiring materials to possess excellent electronic / ionic mixed conductivity, high catalytic activity, and superior structural stability.

[0003] Perovskite oxide Sr2Fe 1.5 Mo 0.5 O 6-δ SFM (Synthetic Fuel Cell) is widely used as a fuel electrode for SOECs due to its excellent reduction stability and certain electrochemical activity. However, the intrinsic catalytic activity of unmodified SFM is limited, especially under medium and low temperature conditions, where insufficient oxygen vacancy concentration inside the material and slow surface reaction kinetics directly limit the improvement of CO2 electrolysis efficiency.

[0004] To improve the electrolytic performance of SFM-based electrodes, existing technologies typically employ elemental doping or composite modification strategies. For example, doping SFM with Mg can enhance structural stability, or combining SFM with Gd... 0.1 Ce 0.9 O 2-δ (GDC) composites are used to improve ionic conductivity. However, the above modification methods still have obvious drawbacks: under reducing atmosphere and high temperature conditions, the material is prone to continuous phase transition and uncontrollable metal dissolution, which leads to rapid decay of CO2 electrolysis reaction (CO2RR) performance and poor long-term operational stability, making it difficult to meet the actual requirements of efficient and stable CO2 electrolysis. Summary of the Invention

[0005] To address the problems of insufficient catalytic activity, low oxygen vacancy concentration, and slow reaction kinetics in the existing SFM-based fuel electrode, this invention aims to provide an SFM-based fuel electrode, a solid oxide electrolyzer containing the same, and a method for preparing the same.

[0006] The SFM-based fuel electrode for solid oxide electrolyzers according to the present invention comprises a perovskite matrix, wherein the perovskite matrix is ​​Sr₂Fe₂ doped at the B' site using Sc. 1.5 Mo 0.5 O 6-δThe perovskite matrix is ​​optionally incorporating Ni at the B-site and / or supported with a YCoO3 second phase, wherein Y is selected from one or more of Pr, Nd, Sm, Eu, and Gd. This invention, by employing Sc doping and optionally incorporating Ni at the B-site and / or supporting a YCoO3 second phase, can significantly improve the oxygen vacancy concentration and surface catalytic activity of the material, accelerate reaction kinetics, suppress Mo-site reduction deactivation, and enhance electrode structural stability.

[0007] In a preferred embodiment, the perovskite matrix has the general formula Sr2Fe. 1.5-y Mo 0.5-x Sc x Ni y O 6-δ Where 0 < x ≤ 0.3, 0 ≤ y ≤ 0.2. This invention limits the range of values ​​for x and y, thereby ensuring the doping modification effect while maintaining the stability of the perovskite structure and avoiding lattice distortion.

[0008] In a preferred embodiment, the molar ratio of YCoO3 to the perovskite matrix is ​​0.01:1 to 0.2:1. This invention controls the content of the second phase, thereby enabling the second phase to fully exert its synergistic catalytic effect, effectively expanding the three-phase interface, and improving electrode catalytic kinetics.

[0009] In a preferred embodiment, the fuel electrode undergoes a reduction treatment, causing Ni at the B site to precipitate in situ as metal nanoparticles. This invention significantly increases the surface catalytic active sites and enhances the electrode's CO2 activation and oxygen exchange capabilities through the in-situ precipitation of metal nanoparticles.

[0010] In a preferred embodiment, the fuel electrode is a composite material formed from GDC and an active component, wherein the mass ratio of the active component to GDC is (5~7):(4~5); wherein the active component is a perovskite matrix or a perovskite matrix supported with a YCoO3 second phase. This invention, by controlling the ratio of the active component to GDC, can achieve a synergistic improvement in catalytic activity and ion transport capability, further reducing electrode polarization resistance and ensuring stable operation of the electrode under high-temperature conditions.

[0011] The solid oxide electrolyzer according to the present invention includes an electrolyte, an air electrode, and the aforementioned fuel electrode. By employing the aforementioned fuel electrode, the solid oxide electrolyzer of the present invention simultaneously achieves high catalytic activity and high stability, reduces the overall polarization resistance of the battery, increases the CO2 electrolysis current density, and enables efficient and long-term stable operation of the battery.

[0012] The method for preparing the fuel electrode according to the present invention includes: P1, preparing a perovskite matrix powder with Sc doping at the B' site and optionally Ni at the B site using a sol-gel method; P2, optionally loading a YCoO3 second phase by a spraying method or an activated carbon black impregnation-sintering method; P3, when the matrix contains Ni, performing heat treatment in a hydrogen-containing reducing atmosphere to allow Ni to precipitate in situ. If a solid-state reaction method or co-precipitation method is used instead of the sol-gel method, the same material uniformity and purity may not be achieved, affecting performance. The present invention, through the above-described stepwise preparation process, ensures high purity and uniform composition of the perovskite matrix, uniform dispersion of the YCoO3 second phase, and controllable in-situ precipitation of Ni nanoparticles, improving the consistency and repeatability of electrode performance, and is suitable for large-scale production.

[0013] In a preferred embodiment, in step P1, when preparing the perovskite matrix powder using the sol-gel method, the calcination temperature of the gel precursor is 1100℃~1300℃, the calcination time is 5~10h, and the heating rate is 2~5℃ / min. By controlling the above calcination conditions, this invention ensures that the perovskite matrix forms a pure phase with high crystallinity, avoids the formation of impurity phases, and provides structural support for the excellent performance of the electrode.

[0014] In a preferred embodiment, step P2 includes preparing a metal salt precursor, which is prepared by mixing Y nitrate and Co nitrate in a molar ratio of 1:1. This invention, by limiting the proportion of the metal salt precursor, ensures that YCoO3 crystals are complete and homogeneous in composition, and that they are tightly bonded to the perovskite matrix interface, thus fully leveraging the catalytic enhancement effect of the second phase.

[0015] In a preferred embodiment, the reducing atmosphere is a 1 vol%~10 vol% H2 / Ar mixture, the heat treatment temperature is 700℃~800℃, and the heat treatment time is 0.1h~0.5h. If the reduction conditions are changed, using 10 vol% H2 / Ar and a reduction time >0.5h to dissolve nickel metal, the results show that the catalytic performance and stability deteriorate. If the reduction temperature is below 700℃, Ni cannot be fully precipitated in situ; if it is above 800℃, Ni particles easily agglomerate. This invention achieves controllable precipitation of Ni nanoparticles by limiting the reduction process parameters, ensuring adequate exposure of catalytic sites and improving electrode performance.

[0016] This invention employs Sc to dope SFM-based perovskites at the B' site, and selectively introduces Ni at the B site and a second phase supported on specific rare-earth cobaltates. This effectively enhances the oxygen vacancy concentration and ion transport capacity of the material, significantly accelerates the kinetics of CO2 electrocatalytic reaction, and improves electrolysis activity under medium and low temperature conditions. Simultaneously, it suppresses phase transitions and uncontrollable metal dissolution in high-temperature reducing atmospheres, enhances electrode structural stability, reduces polarization resistance, and improves CO2 electrolysis current density and long-term operational reliability. This results in a fuel electrode that combines excellent electronic and ionic conductivity, high catalytic activity, and good structural stability, meeting the practical application requirements for efficient and stable CO2 electrolysis. Attached Figure Description

[0017] Figure 1 This is a scanning electron microscope (SEM) image of the solid oxide electrolytic cell fuel electrode prepared in Example 1 of the present invention after Sc doping and Ni in-situ leaching modification.

[0018] Figure 2 This is a SEM image of the solid oxide electrolytic cell fuel electrode prepared in Example 2 of the present invention after being impregnated with PrCoO3 and doped with Sc.

[0019] Figure 3 This is a SEM image of the solid oxide electrolytic cell fuel electrode prepared in Example 3 of the present invention, which is doped with Sc, leached in situ with Ni, and impregnated with GdCoO3.

[0020] Figure 4 This is a SEM image of the solid oxide electrolytic cell fuel electrode prepared in Example 4 of the present invention, which is doped with Sc, leached in situ with Ni, and impregnated with SmCoO3.

[0021] Figure 5 The X-ray diffraction (XRD) patterns of the fuel electrodes obtained in Examples 1-4 of this invention are shown.

[0022] Figure 6 The above are electrochemical impedance spectroscopy (EIS) spectra of the symmetrical cells assembled with fuel electrodes obtained in Comparative Examples 1 and Examples 1-4 of this invention.

[0023] Figure 7 The diagram shows the CO2 electrolysis current density of the single cell assembled with the fuel electrode obtained in Comparative Examples 1 and Examples 1-4 of the present invention in electrolytic cell mode. Detailed Implementation

[0024] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0025] This invention relates to a Sr2Fe 1.5 Mo 0.5 O 6-δThis invention relates to a solid oxide electrolyzer (SOEC) based on SFM (where δ is the oxygen non-stoichiometric parameter, representing the oxygen vacancy concentration in the perovskite lattice, satisfying 0 ≤ δ < 1), its fuel electrode, and its preparation method. Existing SOEC fuel electrode material SFM suffers from low electrochemical activity, high polarization resistance, and slow reaction kinetics during carbon dioxide electrolysis. In unmodified SFM, the electronic structure of the Mo sites restricts the formation and migration of oxygen vacancies, resulting in insufficient surface oxygen exchange capacity. Furthermore, the material has limited surface catalytic active sites under CO2 atmosphere, leading to weak CO2 adsorption and activation capabilities, affecting the reaction rate, and experiencing performance degradation during long-term operation. Therefore, this invention employs a triple synergistic modification approach: Sc doping at B' sites (i.e., Mo sites), in-situ dissolution of Ni from B sites, and impregnation with a YCoO3 second phase. This modulates the electronic structure and oxygen vacancy concentration of the material, enhancing its CO2 adsorption and activation capabilities, thereby improving electrolysis performance and stability to meet the demand for efficient and stable CO2 electrolysis for fuel production.

[0026] Perovskite SFM has an A2BB'O6 structure, where the A site is occupied by an Sr ion, the B site by an Fe ion, and the B' site by a Mo ion.

[0027] This invention uses Sc to dope B' sites (Mo sites) to form Sr2Fe. 1.5 Mo 0.5-x Sc x O 6-δ (SFMS) x (where 0 < x ≤ 0.3, preferably x = 0.25). The results show that cation Sc doping can significantly enhance the electrochemical and oxygen transport performance of the material, not only improving electrocatalytic performance but also reducing the coefficient of thermal expansion and oxygen vacancy formation energy. Sc has a high segregation energy and is often retained in the crystal lattice, contributing to structural stability. Sc doping increases the oxygen vacancy concentration and ion transport capacity of the fuel electrode, and the expanded cell volume synergistically promotes CO2 adsorption and dissociation, significantly improving the overall electrocatalytic performance.

[0028] This invention introduces Ni at the B site (Fe site) to form Sr2Fe. 1.5-y Mo 0.5-x Sc x Ni y O 6-δ (i.e., SFMS) x N y ), where 0≤y≤0.2. Ni has a lower segregation energy than Fe, and under a reducing atmosphere, it promotes the co-dissolution of Fe. This in-situ dissolution greatly increases the oxygen vacancy concentration in the matrix material and increases the three-phase reaction interface for CO2. Ni nanoparticles are precipitated under a reducing atmosphere, which can quickly realize CO2 electrolysis.

[0029] The second phase YCoO3 of this invention consists of independent perovskite particles loaded onto a matrix to form YCoO3-Sr2Fe. 1.5- y Mo 0.5-x Sc x Ni y O 6-δ (i.e., YCO-SFMS) x N y Y is selected from one or more of Pr, Nd, Sm, Eu, and Gd. YCoO3 type perovskite oxides do not contain alkaline earth metal elements, possess mixed ion-electron conductivity and high stability, and the second phase can modulate surface properties and significantly improve electrode activity and stability. In a preferred embodiment, YCO and SFMS... x N y The molar ratio is 0.01:1 to 0.2:1.

[0030] The SOEC of this invention consists of a fuel electrode, an electrolyte, and an air electrode, and is used for high-temperature electrolysis of water to produce hydrogen or carbon dioxide. The fuel electrode is located on the electrolyte side and is responsible for the electrolysis reaction of water or carbon dioxide. Driven by renewable primary energy and industrial waste heat, CO2 is reduced at the fuel electrode to produce CO and O. 2- Oxygen ions migrate through the electrolyte to the air electrode and evolve into oxygen.

[0031] In terms of preparation process, this invention employs a three-stage process, sequentially including sol-gel synthesis, pre-sintering to obtain pure-phase perovskite powder, and final sintering to achieve a strong bond between the electrode and the electrolyte. Specifically, SFMS is synthesized via the sol-gel method. x YCO and SFMS x N y The powder ensures material purity and uniformity. This invention ensures the formation of a pure-phase perovskite structure by precisely controlling the temperature, heating rate, and holding time of powder calcination, barrier layer sintering, electrode sintering, and second-phase sintering. Simultaneously, it guarantees a strong bond between the electrode layer and the electrolyte layer, stable microstructure, clear process parameters, and good repeatability, making it suitable for large-scale preparation of high-performance SOEC electrodes.

[0032] The method of the present invention specifically includes the following steps:

[0033] S1, prepared using the sol-gel method, has the general formula Sr2Fe. 1.5-y Mo 0.5-x Sc x Ni y O 6-δPerovskite powder. Strontium, iron, molybdenum, scandium, and nickel sources were weighed according to the general formula's stoichiometric ratio and dissolved in pure water to form a mixed metal salt solution. Complexing agents citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) were added to the mixed solution, and the pH was adjusted before heating to form a sol. Further heating yielded a dried gel precursor. The gel precursor was sintered at high temperature in air to obtain pure-phase SFMS. x N y Powder. In a preferred embodiment, the strontium source, iron source, molybdenum source, scandium source, and nickel source are Sr(NO3)2, Fe(NO3)3·9H2O, and (NH4)6Mo7O, respectively. 24 The preferred embodiments are Sc(NO3)3·xH2O, Ni(NO3)2·6H2O. In a preferred embodiment, the molar ratio of the total number of metal ions to CA and EDTA is 1:1.5:1 to 1:2:1. In a preferred embodiment, ammonia is used to adjust the pH to 7-8. In a preferred embodiment, the sol-gel formation temperature is 60-100°C, the drying of the gel precursor is carried out at 200-280°C for 3-5 hours, and the precursor is sintered at a heating rate of 2-5°C / min at 1100-1300°C in air for 5-10 hours to obtain Sc and Ni co-doped SFMS. x N y Perovskite powder.

[0034] S2, Gd-doped CeO2 (GDC) is mixed with an organic binder to form a slurry, which is then screen-printed onto the surface of the electrolyte sheet. The resulting layer is sintered at high temperature to obtain a dense and firmly bonded barrier layer. In a preferred embodiment, the binder is a mixture of ethyl cellulose and terpineol in a mass ratio of 0.04:1 to 0.075:1. In a preferred embodiment, the mass ratio of GDC to binder is 1:0.75 to 1:1.25. In a preferred embodiment, the electrolyte sheet is a commercially available LSGM or SSZ electrolyte sheet, or a dense electrolyte sheet made by dry pressing LSGM / SSZ powder. In a preferred embodiment, the barrier layer after screen printing is sintered at a heating rate of 2-5°C / min, reaching 1250-1400°C, and then sintered at a constant temperature for 2-5 hours.

[0035] S3, GDC and SFMS x N y Perovskite powder is mixed and a binder is added to form a slurry, which is then screen-printed onto a GDC barrier layer to form a fuel electrode. GDC is mixed with LaSrCoFeO3 (LSCF) and a binder is added to form a slurry, which is then screen-printed onto the other side of an electrolyte sheet to form an air electrode. The resulting electrode layer is then sintered at high temperature to obtain the basic battery. In a preferred embodiment, GDC and SFMS... x N yThe mass ratio of GDC to LSCF is controlled between 3:7 and 5:5. In a preferred embodiment, the electrode is sintered at a heating rate of 2 to 5 °C / min at 1100 to 1200 °C for 2 to 5 hours, resulting in an electrode layer thickness of approximately 18 to 30 μm.

[0036] S4. Prepare a precursor solution containing Y and Co, and then bond YCoO3 to the fuel electrode or perovskite powder by impregnation or spraying to form YCO-SFMS. x N y Composite structure. In a preferred embodiment, the precursor solution is prepared from a Y-containing nitrate and Co(NO3)2·4H2O. In a preferred embodiment, the molar ratio of the Y-containing nitrate to Co(NO3)2·4H2O is 1:1. In a preferred embodiment, the Y-containing nitrate is Pr(NO3)3·6H2O, Nd(NO3)3·6H2O, Sm(NO3)3·6H2O, Eu(NO3)3·6H2O, or Gd(NO3)3·6H2O. In a preferred embodiment, citric acid is used as a complexing agent, and the molar ratio of metal ions to citric acid is 1:1.5~2. In a preferred embodiment, the concentration of the precursor solution is 0.01mol / L~0.5mol / L. In a preferred embodiment, a spray coating method is used to coat YCoO3 with the electrode material SFMS. x N y The molar ratio is 0.01~0.2:1, and a small-batch, multiple-coating method is used. After spraying, the coating is dried at 100~200℃ for 2~6 hours, and then sintered at 500~1000℃ for 2~5 hours at a heating rate of 2~5℃ / min to form the second phase. In a preferred embodiment, an activated carbon black impregnation method is used. Nano-carbon black is treated with 9mol / L nitric acid at 90℃ for 3 hours, washed, and dried to obtain modified activated carbon black. The impregnation volume ratio of the precursor solution in the activated carbon black is 1:2~5. YCoO3 and electrode material SFMS x N y The molar ratio is 0.01~0.2:1. After impregnation, the mixture is first dried at 100~200℃ for 2~6 hours, and then heated to 500~1000℃ at a heating rate of 2~5℃ / min for sintering for 2~5 hours.

[0037] S5, the battery is subjected to high-temperature treatment in a reducing atmosphere to achieve in-situ precipitation of Ni particles at the B site, resulting in Ni@YCO-SFMS on the fuel electrode side. x The target solid oxide electrolytic cell. In a preferred embodiment, the reducing atmosphere is a 1 vol%~10 vol% H2 / Ar mixture, the reduction temperature is 700~800℃, and the reduction time is 0~2h.

[0038] Comparative Example 1: SFMS 0.2SOEC battery

[0039] S1, according to Sr2Fe 1.5 Mo 0.3 Sc 0.2 O 6-δ (SFMS) 0.2 Weigh out Sr(NO3)2, Fe(NO3)3, and (NH4)6Mo7O in stoichiometric proportions. 24 •4H₂O and Sc(NO₃)₃·xH₂O were dissolved in pure water to form a mixed solution. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) were added to the mixed solution, with the total molar ratio of metal ions to CA and EDTA being 1:1.5:1. The pH was adjusted to 7 with ammonia, and the mixture was stirred at 80°C to form a sol. The sol was then heated at 240°C for 3 hours to obtain a dried gel precursor. The precursor was sintered in air at 1200°C for 5 hours at a heating rate of 5°C / min to obtain SFMS. 0.2 powder.

[0040] S2, dry-pressed LSGM powder, sintered at 1450℃ for 5h at a rate of 2℃ / min to obtain LSGM electrolyte sheets. GDC and binder (ethyl cellulose and terpineol, mass ratio 0.04:1) were ground into a slurry with a GDC to binder mass ratio of 1:1. A barrier layer was printed on the electrolyte sheet using screen printing and sintered at 1250℃ at a rate of 2℃ / min for 2h.

[0041] S3, GDC and SFMS 0.2 GDC and LSCF were mixed at a mass ratio of 4:6, and a binder was added and ground into a slurry. Fuel electrodes were then printed onto the GDC barrier layer using screen printing. GDC and LSCF were mixed at a mass ratio of 4:6, and a binder was added and ground into a slurry. Air electrodes were then printed onto the LSGM using screen printing. SFMS were prepared separately. 0.2 -GDC|GDC|LSGM|GDC|SFMS 0.2 -GDC symmetrical battery and SFMS 0.2 -GDC|GDC|LSGM|LSCF-GDC single cell, the fuel electrode and air electrode were sintered at 1200℃ and 1100℃ respectively at 2℃ / min for 2h to form an effective area of ​​0.5cm². 2 An electrode layer with a thickness of approximately 24 μm.

[0042] Example 1: SFMS 0.2 N 0.1 SOEC battery

[0043] S1, according to Sr2Fe 1.4 Mo 0.3 Sc 0.2 Ni 0.1 O6-δ (SFMS) 0.2 N 0.1 Weigh out Sr(NO3)2, Fe(NO3)3, and (NH4)6Mo7O in stoichiometric proportions. 24 ·4H₂O, Sc(NO₃)₃·xH₂O, and Ni(NO₃)₂·6H₂O were dissolved in pure water to form a mixed solution. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) were added to the mixed solution, with the total molar ratio of metal ions to CA and EDTA being 1:1.5:1. The pH was adjusted to 7 with ammonia, and the mixture was stirred at 80°C to form a sol. The sol was then heated at 240°C for 3 hours to obtain a dried gel precursor. The precursor was sintered in air at 1200°C for 5 hours at a heating rate of 5°C / min to obtain SFMS. 0.2 N 0.1 powder.

[0044] S2, dry-pressed LSGM powder, sintered at 1450℃ for 5h at a rate of 2℃ / min to obtain LSGM electrolyte sheets. GDC and binder (ethyl cellulose and terpineol, mass ratio 0.04:1) were ground into a slurry with a GDC to binder mass ratio of 1:1. A barrier layer was printed on the electrolyte sheet using screen printing and sintered at 1250℃ at a rate of 2℃ / min for 2h.

[0045] S3, GDC and SFMS 0.2 N 0.1 GDC and LSCF were mixed at a mass ratio of 4:6, and a binder was added and ground into a slurry. Fuel electrodes were then printed onto the GDC barrier layer using screen printing. GDC and LSCF were mixed at a mass ratio of 4:6, and a binder was added and ground into a slurry. Air electrodes were then printed onto the LSGM using screen printing. SFMS were prepared separately. 0.2 N 0.1 -GDC|GDC|LSGM|GDC|SFMS 0.2 N 0.1 -GDC symmetrical battery and SFMS 0.2 N 0.1 -GDC|GDC|LSGM|LSCF-GDC single cell, the fuel electrode and air electrode were sintered at 1200℃ and 1100℃ respectively at 2℃ / min for 2h to form an effective area of ​​0.5cm². 2 An electrode layer with a thickness of approximately 24 μm.

[0046] S5, Ni nanoparticles were precipitated by introducing 10% H2 / Ar into the fuel electrode side for 1 hour.

[0047] like Figure 1As shown, the solid oxide electrolytic cell fuel electrode prepared in this embodiment has an intact overall structure without obvious cracks, uniform internal pore distribution, and Ni nanoparticles uniformly dispersed on the substrate surface, providing microstructural support for excellent CO2 electrolysis performance.

[0048] Example 2: PCO-SFMS 0.25 SOEC battery

[0049] S1, according to Sr2Fe 1.5 Mo 0.25 Sc 0.25 O 6-δ (SFMS) 0.25 Weigh out Sr(NO3)2, Fe(NO3)3, and (NH4)6Mo7O in stoichiometric proportions. 24 •4H₂O and Sc(NO₃)₃·xH₂O were dissolved in pure water to form a mixed solution. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) were added to the mixed solution, with the total molar ratio of metal ions to CA and EDTA being 1:1.5:1. The pH was adjusted to 7 with ammonia, and the mixture was stirred at 80°C to form a sol. The sol was then heated at 240°C for 3 hours to obtain a dried gel precursor. The precursor was sintered in air at 1200°C for 5 hours at a heating rate of 5°C / min to obtain SFMS. 0.25 powder.

[0050] S2, GDC and binder (ethyl cellulose and terpineol, mass ratio 0.04:1) are ground into a slurry with a mass ratio of GDC to binder of 1:1. A barrier layer is printed on the LSGM electrolyte sheet using screen printing and sintered at 1250℃ at 2℃ / min for 2h.

[0051] S3, GDC and SFMS 0.25 GDC and LSCF were mixed at a mass ratio of 4:6, and a binder was added and ground into a slurry. Fuel electrodes were then printed onto the GDC barrier layer using screen printing. GDC and LSCF were mixed at a mass ratio of 4:6, and a binder was added and ground into a slurry. Air electrodes were then printed onto the LSGM using screen printing. SFMS were prepared separately. 0.25 -GDC|GDC|LSGM|GDC|SFMS 0.25 -GDC symmetrical battery and SFMS 0.25 -GDC|GDC|LSGM|LSCF-GDC single cell, the fuel electrode and air electrode were sintered at 1200℃ and 1100℃ respectively at 2℃ / min for 2h to form an effective area of ​​0.5cm². 2 An electrode layer with a thickness of approximately 24 μm.

[0052] S4, weigh Pr(NO3)3·6H2O and Co(NO3)2·4H2O and dissolve them in deionized water, add CA as a complexing agent, the molar ratio of metal ions to CA is 1:1.5 to obtain PCO impregnation solution, and spray the impregnated PCO onto the fuel electrode side of symmetrical cells and single cells, wherein the PCO in the PCO precursor solution is mixed with the fuel electrode SFMS on the fuel electrode side. 0.25 The molar ratio is 0.1:1, and it is applied in small amounts multiple times to SFMS. 0.25 After the fuel electrode side is dried at 100~200℃ for 2~6 hours, the above-mentioned battery cells are then placed in a muffle furnace for sintering, and the temperature is increased at 2℃ / min to 800℃ for 2 hours to form the second phase.

[0053] like Figure 2 As shown, in the solid oxide electrolyzer fuel electrode prepared in this embodiment, PrCoO3 is supported on porous SFMS in the form of a continuous and uniform nanophase thin film. 0.25 The electrode substrate surface exhibits a tight bond between the two-phase interface and sufficient three-phase reaction interface, verifying the effectiveness of the impregnation modification process of this invention and providing microstructural support for the electrode's excellent CO2 electrolysis performance.

[0054] Example 3: GCO-SFMS 0.2 N 0.1 SOEC battery

[0055] S1, according to Sr2Fe 1.4 Mo 0.3 Sc 0.2 N 0.1 O 6-δ (SFMS) 0.2 N 0.1 Weigh out Sr(NO3)2, Fe(NO3)3, and (NH4)6Mo7O in stoichiometric proportions. 24 ·4H₂O, Sc(NO₃)₃·xH₂O, and Ni(NO₃)₂·6H₂O were dissolved in pure water to form a mixed solution. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) were added to the mixed solution, with the total molar ratio of metal ions to CA and EDTA being 1:1.5:1. The pH was adjusted to 7 with ammonia, and the mixture was stirred at 80°C to form a sol. The sol was then heated at 240°C for 3 hours to obtain a dried gel precursor. The precursor was sintered in air at 1200°C for 5 hours at a heating rate of 5°C / min to obtain SFMS. 0.2 N 0.1 powder.

[0056] S2, GDC and binder (ethyl cellulose and terpineol, mass ratio 0.04:1) are ground into a slurry with a mass ratio of GDC to binder of 1:1. A barrier layer is printed on the SSZ electrolyte sheet using screen printing. The sheet is heated to 1250℃ in a muffle furnace at a heating rate of 2℃ / min and sintered at a constant temperature for 2h.

[0057] S3, GDC and SFMS 0.2 N 0.1 GDC and LSCF were mixed at a mass ratio of 4:6, and a binder was added and ground into a slurry. Fuel electrodes were then printed onto the GDC barrier layer using screen printing. GDC and LSCF were mixed at a mass ratio of 4:6, and a binder was added and ground into a slurry. Air electrodes were then printed onto the LSGM using screen printing. SFMS were prepared separately. 0.2 N 0.1 -GDC|GDC|SSZ|GDC|SFMS 0.2 N 0.1 -GDC symmetrical battery and SFMS 0.2 N 0.1 -GDC|GDC|SSZ|LSCF-GDC single cell, the fuel electrode and air electrode were sintered at 1200℃ and 1100℃ respectively at 2℃ / min for 2h to form an effective area of ​​0.5cm². 2 An electrode layer with a thickness of approximately 24 μm.

[0058] S4, weigh Gd(NO3)3·6H2O and Co(NO3)2·4H2O and dissolve them in deionized water, add CA as a complexing agent, the molar ratio of metal ions to CA is 1:2 to obtain GCO impregnation solution, and spray impregnate GCO onto the fuel electrode side of symmetrical cells and single cells, wherein the GCO in the GCO precursor solution is mixed with the fuel electrode SFMS on the fuel electrode side. 0.2 N 0.1 The molar ratio is 0.08:1, and it is applied in small amounts multiple times on SFMS. 0.2 N 0.1 After the fuel electrode side is dried at 100~200℃ for 2~6 hours, the above-mentioned battery cells are then placed in a muffle furnace for sintering, and the temperature is increased at 2℃ / min to 600℃ for 2 hours to form the second phase.

[0059] S5, Ni nanoparticles were precipitated by introducing 10% H2 / Ar into the fuel electrode side for 1 hour.

[0060] like Figure 3 As shown, the solid oxide electrolytic cell fuel electrode prepared in this embodiment has a complete perovskite matrix structure, with Ni nanoparticles and GdCoO3 second phase uniformly dispersed on the matrix surface, a well-developed pore structure, sufficient three-phase reaction interface, and significant multi-strategy synergistic modification effect.

[0061] Example 4: SCO-SFMS 0.3 N 0.15 SOEC battery

[0062] S1, according to Sr2Fe 1.35 Mo 0.2 Sc 0.3 Ni 0.15 O 6-δ (SFMS 0.3 N 0.15 Weigh out Sr(NO3)2, Fe(NO3)3, and (NH4)6Mo7O in stoichiometric proportions. 24 ·4H₂O, Sc(NO₃)₃·xH₂O, and Ni(NO₃)₂·6H₂O were dissolved in pure water to form a mixed solution. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) were added to the mixed solution, with the total molar ratio of metal ions to CA and EDTA being 1:1.5:1. The pH was adjusted to 7 with ammonia, and the mixture was stirred at 80°C to form a sol. The sol was then heated at 240°C for 3 hours to obtain a dried gel precursor. The precursor was sintered in air at 1200°C for 5 hours at a heating rate of 5°C / min to obtain SFMS. 0.3 N 0.15 powder.

[0063] S2, GDC and binder (ethyl cellulose and terpineol, mass ratio 0.04:1) are ground into a slurry with a mass ratio of GDC to binder of 1:1. A barrier layer is printed on the LSGM electrolyte sheet using screen printing and sintered at 1250℃ at 2℃ / min for 2h.

[0064] S3, weigh Sm(NO3)3·6H2O and Co(NO3)2·4H2O and dissolve them in deionized water in a molar ratio of 1:1. Add citric acid as a complexing agent. The molar ratio of metal ions to citric acid is between 1:1.5 and 2, and the concentration of metal ions in the solution is 0.1 mol / L. After stirring and dissolving, a precursor solution is obtained. The above solution is impregnated in activated carbon black, which is obtained by acid treatment of nano-sized carbon black powder in 9 mol / L nitric acid at 90°C for 3 hours, followed by washing and drying. The impregnation volume ratio of the solution to the activated carbon black is 1:4. The above material is mixed with the SFMSxNy powder material prepared in S1, wherein the molar ratio of YCO3 to the electrode material SFMSxNy is 0.09:1. The mixture is first dried in an oven at 150°C for 5 hours, and then placed in a muffle furnace and sintered at 900°C at a heating rate of 2°C / min for 3 hours to form a second phase.

[0065] S4: The materials synthesized from GDC and S3 are mixed at a mass ratio of 4:6, a binder is added, and the mixture is ground into a slurry. Fuel electrodes are then printed onto the GDC barrier layer using screen printing. GDC and LSCF are mixed at a mass ratio of 4:6, a binder is added, and the mixture is ground into a slurry. Air electrodes are then printed onto the LSGM using screen printing. SFMS are prepared separately. 0.3 N 0.15 -GDC|GDC|LSGM|GDC|SFMS 0.3 N 0.15 -GDC symmetrical battery and SFMS 0.3 N 0.15 -GDC|GDC|LSGM|LSCF-GDC single cell, the fuel electrode and air electrode were sintered at 1200℃ and 1100℃ respectively at 2℃ / min for 2h to form an effective area of ​​0.5cm². 2 An electrode layer with a thickness of approximately 24 μm.

[0066] S5, Ni nanoparticles were precipitated by introducing 10% H2 / Ar into the fuel electrode side for 1 hour.

[0067] like Figure 4 As shown, in the solid oxide electrolyzer fuel electrode prepared in this embodiment, SmCoO3 is loaded in the form of a uniformly dispersed nanophase on porous SFMS. 0.3 N 0.15 A well-developed porous composite structure is formed on the surface of the electrode substrate, with uniformly distributed Ni particles and tight interfacial bonding. The carbon black-assisted loading process effectively improves the dispersion of the active phase and the reaction interface.

[0068] The method of this invention also includes X-ray diffraction (XRD) characterization of the prepared fuel electrode. For example... Figure 5 As shown, all samples in Examples 1-4 exhibited characteristic diffraction peaks of pure-phase perovskite, with no impurities and high crystallinity, indicating that Sc doping, Ni doping, and YCoO3 impregnation did not damage the perovskite structure, and the material had excellent phase purity and structural stability.

[0069] The method of this invention also includes electrochemical performance testing of the prepared symmetrical cells and single cells to evaluate the CO2 electroreduction (CO2RR) catalytic activity of the fuel electrode. For the symmetrical cell test, dry, pure carbon dioxide is supplied to the test fixture at a flow rate of 40 SCCM. EIS measurements are performed in the frequency range of 1 MHz to 0.01 Hz and the temperature range of 800°C to 650°C at 50°C intervals. For the single cell test, the fuel electrode is sealed with ceramic adhesive to an alumina tube to evaluate the CO2RR catalytic activity of the fuel electrode. For the single cell test, pure CO2 is supplied to the fuel electrode side at a flow rate of 40 SCCM, while the air electrode side is exposed to ambient air to test the current density for CO2 electrolysis in the single cell.

[0070] like Figure 6 As shown, compared with Comparative Example 1 which only has Sc doping, the polarization resistance of the electrodes in Examples 1 to 4 is significantly reduced. Among them, the polarization resistance of Example 3 (Sc doping + Ni in-situ dissolution + GdCoO3 impregnation) is the lowest, which verifies that the synergistic modification strategy of Sc doping, Ni in-situ dissolution and YCoO3 impregnation of the present invention can effectively accelerate the electrochemical reaction kinetics, reduce electrode polarization loss and improve CO2 electrolysis performance.

[0071] like Figure 7 As shown, compared with Comparative Example 1 which only has Sc doping, the electrodes of Examples 1 to 4 all showed significantly improved CO2 electrolysis current density at the same voltage. Among them, Example 4 (Sc doping + Ni in-situ dissolution + SmCoO3 impregnation + carbon black assistance) had the highest current density, which verifies that the synergistic modification strategy of the present invention can effectively improve the CO2 electrolysis catalytic activity and electrolysis efficiency of the electrode and reduce electrolysis energy consumption.

[0072] Thus, this invention can significantly improve the oxygen vacancy concentration and surface catalytic activity of SFM, increase the electrolysis current density, and reduce the polarization resistance. YCO impregnation significantly increases the three-phase reaction interface and suppresses Sr segregation at the interface, forming a nano-coating on the parent material surface and promoting CO2 adsorption. Nickel leaching simultaneously generates highly active metal nanoparticles and oxygen-vacancy-rich perovskite on the material surface, greatly enhancing catalytic activity, and the metal-oxide heterojunction interface produces a CO2RR synergistic effect. The material exhibits excellent anti-carbon deposition ability, structural stability, and reversible self-repair potential. Moreover, this invention suppresses the reduction deactivation of Mo sites under CO2 atmosphere through Sc doping, resulting in low long-term electrode decay; YCoO3 further reduces decay, maintains structural stability, and has reversible self-repair potential; in-situ Ni leaching ensures good stability of the material under both high and low voltages, with uniformly distributed reduced particles and excellent anti-carbon deposition performance. In addition, this invention uses the sol-gel method, with clear process parameters, good controllability and repeatability, making it suitable for batch preparation and large-scale production.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A SFM-based fuel electrode for use in a solid oxide electrolyzer, characterized in that, Includes a perovskite matrix, wherein the perovskite matrix is ​​Sr2Fe doped at the B' site using Sc. 1.5 Mo 0.5 O 6-δ The base material; the perovskite matrix optionally incorporates Ni at the B site and / or is supported with a YCoO3 second phase, wherein Y is selected from one or more of Pr, Nd, Sm, Eu and Gd.

2. The fuel electrode according to claim 1, characterized in that, The perovskite matrix has the general formula Sr2Fe. 1.5- y Mo 0.5-x Sc x Ni y O 6-δ , where 0 < x ≤ 0.3, 0 ≤ y ≤ 0.

2.

3. The fuel electrode according to claim 2, characterized in that, The molar ratio of YCoO3 to the perovskite matrix is ​​0.01:1 to 0.2:

1.

4. The fuel electrode according to claim 2, characterized in that, The fuel electrode undergoes a reduction treatment, causing Ni at the B site to precipitate in situ in the form of metal nanoparticles.

5. The fuel electrode according to claim 1, characterized in that, The fuel electrode is a composite material formed by GDC and an active component, wherein the mass ratio of the active component to GDC is (5~7):(4~5); wherein the active component is a perovskite matrix or a perovskite matrix loaded with YCoO3 second phase.

6. A solid oxide electrolytic cell, characterized in that, It includes an electrolyte, an air electrode, and a fuel electrode as described in any one of claims 1 to 5.

7. A method for preparing a fuel electrode according to any one of claims 1 to 5, characterized in that, include: P1, perovskite matrix powder with Sc doping at B' site and optional Ni content at B site was prepared by sol-gel method; P2, optionally loaded with YCoO3 second phase by spraying or activated carbon black impregnation-sintering method; P3, when the matrix contains Ni, is heat-treated in a hydrogen-containing reducing atmosphere to allow Ni to precipitate in situ.

8. The preparation method according to claim 7, characterized in that, In step P1, when preparing perovskite matrix powder by sol-gel method, the calcination temperature of the gel precursor is 1100℃~1300℃, the calcination time is 5~10h, and the heating rate is 2~5℃ / min.

9. The preparation method according to claim 7, characterized in that, Step P2 includes preparing a metal salt precursor, which is prepared by mixing nitrate of Y and nitrate of Co in a molar ratio of 1:

1.

10. The preparation method according to claim 7, characterized in that, The reducing atmosphere is a 1 vol%~10 vol% H2 / Ar mixture, the heat treatment temperature is 700℃~800℃, and the heat treatment time is 0.1h~0.5h.

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