A novel solid oxide electrolysis cell oxygen electrode and method of making same

Abstract

The application belongs to the field of high-temperature steam electrolysis and solid oxide electrolysis cell, and relates to a novel oxygen electrode for hydrogen production by solid oxide electrolysis cell and a preparation method thereof. x Co 1‑x O 2‑δ or LSF-YSZ-A x Co 1‑x O 2‑δ or LSM-GDC-A x Co 1‑x O 2‑δ or LSF-GDC-A x Co 1‑x O 2‑δ The novel oxygen electrode. The LSM or LSF powder is prepared by an ammonium citrate method, the oxygen electrode is prepared, and A x Co 1‑x O 2‑δ The impregnation solution is impregnated on the surface and micropores of the oxygen electrode, the content of A x Co 1‑ x O 2‑δ solution is controlled to control the content of A x Co 1‑x O 2‑δ in the oxygen electrode. Compared with the traditional LSM or LSF electrode, the novel oxygen electrode prepared by the application significantly improves the performance of the electrolysis cell.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature steam electrolysis for hydrogen production and solid oxide electrolysis cells. Specifically, it relates to a novel oxygen electrode for hydrogen production using a solid oxide electrolysis cell and its preparation method. Background Technology

[0002] In recent years, renewable energy has attracted considerable interest. A fundamental issue with renewable energy sources such as solar, wind, hydropower, and geothermal energy is that they must be supplied and demand matched, making energy storage crucial. Energy storage in the form of hydrogen is also essential and has been extensively discussed for many years, with a growing trend towards a hydrogen economy. Hydrogen is clean; in fact, it can be produced from abundant water. When it is converted into usable electricity through fuel cells, the byproduct is harmless water. Currently, hydrogen is primarily produced from fossil fuels, specifically through natural gas steam reforming. However, the conversion of fossil fuels is neither renewable nor clean. Hydrogen can be produced in a more environmentally friendly way through thermochemical water splitting, photocatalytic water splitting, or water electrolysis. Currently, thermochemical and photocatalytic hydrogen production methods are too inefficient to be economically competitive. Water electrolysis is by far the most practical and promising large-scale renewable hydrogen production technology. Solid oxide electrolyzers (SOECs) are electrochemical devices that convert electrical and thermal energy into the chemical energy of fuels in a highly efficient and environmentally friendly manner at medium to high temperatures. SOEC operates within a temperature range of 600-1000℃. The higher operating temperature accelerates the electrode reaction rate, significantly reducing the electrode polarization voltage and effectively minimizing irreversible energy loss during electrolysis. Simultaneously, the energy required for electrolysis and the electrolysis voltage decrease with increasing temperature, further reducing energy consumption. Therefore, SOEC offers higher electrolysis efficiency and energy conversion rate than low-temperature electrolysis technologies and is considered one of the most widely applicable technologies for hydrogen production.

[0003] In hydrogen production using solid oxide electrolyzers (SOECs), the slow kinetics of oxygen release at the anode are a major factor limiting SOEC performance. Lanthanum strontium manganese oxide (LSM-YSZ) composites, as traditional anode materials, possess high chemical and structural stability and good compatibility with YSZ electrolytes. However, their low ionic conductivity results in insufficient oxygen evolution reaction (OER) activity. To improve the activity of LSM-YSZ electrodes, most current improvement methods involve doping the A or B sites of LSM to increase its electronic conductivity, but the performance improvement is limited. Some studies have also reported the use of other materials, such as BaCo. x Fe y Zr m Y 1-x-y-m O 3-δ (BCFZY), Ba 1-x Sr x Co 1-yFe y O 3-δ Materials such as BSCF are available, but these materials are not suitable for high-temperature electrolyzers, and their hydrogen production efficiency needs to be improved.

[0004] In order to significantly improve the performance of the electrolyzer and the hydrogen production efficiency, this patent improves the electrolysis performance by adding new active components, improving the anode slurry and calcination process, and is expected to make it a high-performance oxygen electrode in SOEC. Summary of the Invention

[0005] This invention proposes a novel oxygen electrode material for SOEC hydrogen production and its preparation method. Compared with traditional LSM or LSF electrodes, the novel oxygen electrode prepared by this invention significantly improves the performance of the electrolyzer.

[0006] The technical solution of the present invention is as follows:

[0007] This invention provides an oxygen electrode for a solid oxide electrolytic cell, the composition of which includes LSM-YSZ-A. x Co 1- x O 2-δ Or LSF-YSZ-A x Co 1-x O 2-δ Or LSM-GDC-A x Co 1-x O 2-δ Or LSF-GDC-A x Co 1-x O 2-δ Where 0.1≤x≤0.9, δ represents the oxygen vacancy value, which is a general expression for oxide materials;

[0008] The A x Co 1-x O 2-δ In this context, A is one or more of Ce, Pr, Nd, Sm, Gd, and Yb; the chemical formula of the LSM is La. x Sr 1-x MnO 3-δ , 0.1≤x≤0.9; LSF chemical formula is La x Sr 1-x FeO 3-δ , 0.1≤x≤0.9;; The chemical formula of YSZ is Y x Zr 1-x O2, 0.1≤x≤0.9; GDC chemical formula is Gd x Ce 1-x O2, 0.1≤x≤0.9.

[0009] In the above technical solution, further, the A xCo 1-x O 2-δ The average particle size of the nanoparticles is 20–40 nm; the molar ratio of the A and Co metal ions is 0.1–10:1.

[0010] In the above technical solution, the thickness of the oxygen electrode in the solid oxide electrolytic cell is further 10-50 μm.

[0011] The present invention also provides a method for preparing an oxygen electrode for a solid oxide electrolytic cell, comprising the following steps:

[0012] S1. Prepare LSM-YSZ or LSF-YSZ or LSM-GDC or LSF-GDC oxygen electrodes;

[0013] S2, Prepare A at a concentration of 0.3–1 mol / L x Co 1-x O 2-δ Solution:

[0014] According to chemical formula A x Co 1-x O 2-δ Weigh out nitrate powder and cobalt nitrate powder of A, dissolve them in water, and then add a complexing agent in a molar amount of 0.25 to 2.5 times the total metal ions; heat and stir at 60 to 90°C, and adjust the pH of the solution to ≥ 8 after dissolution.

[0015] S3, Impregnation and roasting:

[0016] The oxygen electrode from step S1 is impregnated with the solution prepared in step S2 1 to 5 times, and then calcined at 700 to 1000°C for 3 to 4 hours to obtain the final product; preferably, 2-6 μL of the solution from step S2 is taken, and the impregnation method is vacuum impregnation.

[0017] The A x Co 1-x O 2-δ The impregnation amount is 1 wt% to 15 wt% of the mass of the LSM-YSZ, LSF-YSZ, LSM-GDC, or LSF-GDC oxygen electrode; preferably 7-11 wt%.

[0018] In the above technical solution, the preparation method of the oxygen electrode in step S1 further includes the following steps:

[0019] (1) Preparation of anode powder:

[0020] According to the chemical formula La of LSM x Sr 1-x MnO 3-δ Or the chemical formula of LSF, La x Sr 1-x FeO 3-δWeigh out the metal ion nitrate powder, dissolve it in water, add a complexing agent in a molar amount of 0.25 to 2.5 times the total metal ions, heat and stir at 60 to 90°C for 15 to 20 minutes, adjust the pH of the solution to ≤1 after dissolution, and continue to evaporate at 60 to 90°C until the solution becomes a transparent gel-like liquid.

[0021] The gel-like substance is heated at 200–500°C for 10–30 minutes until it undergoes self-propagating combustion to form a fluffy powder, thus obtaining the primary powder; the primary powder is LSM primary powder or LSF primary powder.

[0022] The primary powder is calcined at 700–1000℃ for 5–10 hours, and then ground through a 180-mesh steel sieve to obtain secondary powder; the secondary powder is LSM secondary powder or LSF secondary powder.

[0023] The secondary powder is mixed with YSZ or GDC powder, solvent A is added and mixed evenly, the solvent is dried and then ground, and the mixture is passed through a 180-mesh steel sieve to obtain the mixed powder; the solvent A is one or more of ethanol, terpineol, and n-butanol.

[0024] (2) Preparation of anode slurry:

[0025] The mixed powder obtained in step (1) is added to the auxiliary components and solvent B, and after thorough grinding, it is coated onto a cathode-supported semi-electrolytic cell sheet or an electrolyte-supported semi-electrolytic cell sheet and air-dried to obtain a semi-electrolytic cell sheet; the auxiliary components are pore-forming agents, dispersants, and binders; the solvent B is one or more of terpineol, toluene, and ethanol; the coating method is screen printing or slurry coating.

[0026] (3) Roasting:

[0027] The semi-electrolytic cell sheet obtained in step (2) is calcined at 800-1000°C for 3-5 hours to obtain the oxygen electrode described in step S1.

[0028] In the above technical solution, the mass ratio of the secondary powder to YSZ or GDC powder is 1:2 to 2:1; the mass ratio of the mixed powder to the auxiliary components is 1:2 to 2:1.

[0029] In the above technical solution, further, the auxiliary material components include a pore-forming agent content of 5-20 wt%, a dispersant content of 1-5 wt%, and a binder content of 5-20 wt%; the pore-forming agent is any one of starch, corn flour, and polymethyl methacrylate; the dispersant is fish oil; the binder is ethyl cellulose or polyvinyl butyral 79 (PVB79); and the solvent B accounts for 60-90 wt% of the anode slurry.

[0030] In the above technical solution, the complexing agent is any one of ammonium citrate, glycine, urea, EDTA, and citric acid.

[0031] In the above technical solution, further, in the cathode-supported semi-electrolytic cell sheet, the cathode support layer is made of Ni-YSZ or Ni-GDC; in the electrolyte-supported semi-electrolytic cell sheet, the electrolyte support layer is made of YSZ or GDC.

[0032] In the above technical solution, the cathode-supported or electrolyte-supported semi-electrolytic cell sheet is further prepared by casting, calendering, or dry powder pressing.

[0033] Beneficial effects

[0034] (1) The present invention provides a novel oxygen electrode for a solid oxide electrolytic cell. Firstly, LSM or LSF powder and A are prepared using the ammonium citrate method. x Co 1-x O 2-δ The substrate for the oxygen electrode is then prepared using a paste coating method or a screen printing method. Finally, the active component is added using a permeation method, by changing the volume of A added. x Co 1-x O 2-δ Solution to control A in oxygen electrode x Co 1-x O 2-δ The content of [specific element] indicates that this is a novel oxygen electrode for use in high-efficiency hydrogen production solid oxide electrolyzers.

[0035] (2) The anode slurry formulation of this invention includes LSM (or LSF)-YSZ (or GDC) mixed powder and auxiliary components. The oxygen electrode is made by mixing LSM (or LSF) and YSZ (or GDC) powder to improve the compatibility with the electrolyte in the electrolytic cell and effectively solve problems such as thermal matching.

[0036] (3) This invention enables the oxygen electrode to possess a rich microporous structure and good mechanical properties by controlling the addition of appropriate auxiliary components. The auxiliary components include pore-forming agents, dispersants, binders, and solvents. The addition of pore-forming agents is to create more microporous structures within the oxygen electrode, facilitating ion transport and oxygen delivery. The content of the pore-forming agent in this invention is controlled at 5–20 wt% of the auxiliary components. Too little content will not create a rich microporous structure, while too much content may lead to a decrease in the mechanical properties of the oxygen electrode. The addition of dispersants and solvents is to ensure that LSM (or LSF) and YSZ (or GDC) are thoroughly mixed and dispersed. The addition of binders is to allow the well-dispersed particles or clusters to adhere together at the submicroscopic scale, which is beneficial for the subsequent calcination and shaping of the oxygen electrode. The binder content is controlled at 5–20 wt% of the auxiliary components. The binder content is added according to the particle size of the powder; when the particle size is small, a relatively large amount of binder needs to be added to ensure sufficient adhesion of the slurry.

[0037] (4) This invention employs a novel active component impregnated in an LSM (or LSF)-YSZ (or GDC) anode, which significantly improves the electrolytic performance of the electrolytic cell. The active component is A. x Co 1-x O 2-δ Nanoparticles, wherein A is one or more of Ce, Pr, Nd, Sm, Gd, Yb, and Zr, and the ratio of A to Co metal ions is between 0.1 and 10. x Co 1-x O 2-δ Among nanoparticles, Co is an element in Group 1 of the periodic table, a variable-valence metal, with a small particle size and relatively reactive properties. Doping with Co is beneficial for improving the electrocatalytic performance of the electrolytic cell; however, its high reactivity and small particle size can easily lead to undesirable reactions such as agglomeration. Al (one or more of Ce, Pr, Nd, Sm, Gd, Yb, and Zr) is an element in Group 2 or 3 of the periodic table, with stable properties and relatively large particle size. Doping with Al is beneficial for increasing the mechanical and chemical stability of the oxygen electrode structure. The Al synthesized in this invention... x Co 1-x O 2-δ Nanoparticles with both A and Co as impregnating active components have abundant surface oxygen vacancies and high lattice oxygen mobility, accelerating the oxygen evolution reaction in steam electrolysis mode. LSM (or LSF)-YSZ (or GDC)-A x Co 1-x O 2-δ The novel oxygen electrode can improve the catalytic activity of the oxygen electrode while maintaining good chemical stability, thereby increasing the electrochemical performance of the battery.

[0038] (5) In addition, according to the test comparison of electrolytic cells, compared with the traditional non-impregnated Ax Co 1-x O 2-δ LSM or LSF electrodes made of nanoparticles, specifically LSM (or LSF)-YSZ (or GDC)-A in this invention. x Co 1-x O 2-δ The novel oxygen electrode exhibits higher hydrogen production performance in electrolyzer tests. Attached Figure Description

[0039] Figure 1 Example 1Ce 0.87 Co 0.13 O 2-δ LSM-YSZ and LSM-YSZ-Ce 0.87 Co 0.13 O 2-δ XRD pattern;

[0040] Figure 2 This is a SEM image of the cross-section of the LSM-YSZ oxygen electrode, which is a comparative example.

[0041] Figure 3 Example 3: LSM-YSZ-6.9wt% Ce 0.87 Co 0.13 O 2-δ SEM image of oxygen electrode cross-section;

[0042] Figure 4 Example 4: LSM-YSZ-7.8wt% Ce 0.87 Co 0.13 O 2-δ SEM image of oxygen electrode cross-section;

[0043] Figure 5 It is LSM-YSZ, LSM-YSZ-2.3wt%Ce at 800℃ 0.87 Co 0.13 O 2-δ LSM-YSZ-4.3wt%Ce 0.87 Co 0.13 O 2-δ LSM-YSZ-6.9wt%Ce 0.87 Co 0.13 O 2-δ and LSM-YSZ-7.8wt%Ce 0.87 Co 0.13 O 2-δ The voltage-current density curve.

[0044] Figure 6 It is LSM-GDC and LSM-GDC-Pr with different impregnation amounts 0.89 Co 0.11 O2-δ The current density trend graph. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0046] Comparative Example 1:

[0047] The preparation method of the oxygen electrode for a solid oxide electrolytic cell includes the following steps:

[0048] (1) Synthesis of La using the ammonium citrate method 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0049] Prepare La solutions with a molar concentration of 0.5 mol / L. 3+ 、Sr 2+ Mn 3+ The nitrate solution was accurately weighed and transferred at a ratio of 4:1:5 to obtain La. 3+ 、Sr 2+ Mn 3+ A nitrate solution was placed in a 500 ml beaker. The mixture was heated and stirred at 60°C for 20 minutes to obtain a mixed La. 3+ 、Sr 2+ Mn 3+ The solution was prepared using nitrate solution. Ammonium citrate (analytical grade) was added at a molar ratio of 1.5:1 to metal ions. The pH of the solution was adjusted to 8 with ammonia (analytical grade) to make it clear and transparent. The solution was then heated at 70°C with stirring to evaporate the solvent until it became gel-like. The solution was poured into a 1000ml evaporating dish and heated in an electric furnace to allow the system to self-propagate and burn, yielding a fluffy powder. The collected initial powder was calcined in a muffle furnace at 1000°C for 6 hours, ground, and passed through an 180-mesh steel sieve to obtain La. 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0050] (2)La 0.8 Sr 0.2 MnO 3-δ Preparation of YSZ oxygen electrode

[0051] The La prepared in (1) 0.8 Sr 0.2 MnO 3-δAnode powder and YSZ powder (8% Y2O3-stabilized ZrO2, Tosho, Japan) were mixed in a 3:2 ratio. Ethanol was added and the mixture was ground until homogeneous. The solvent was then dried under a heat lamp, and the mixture was transferred to a mortar and ground through a 180-mesh steel sieve. 40 wt% of auxiliary components (including pore-forming starch, dispersant fish oil, binder polyvinyl butyral 79, and solvent terpineol) were added. 0.0080 g of the mixture was coated onto a cathode-supported semi-electrolytic cell sheet using a slurry coating method. The resulting product was then sintered in a muffle furnace at 1000°C for 3 hours to obtain La. 0.8 Sr 0.2 MnO 3-δ -YSZ oxygen electrode.

[0052] (3) SOEC test: Electrolysis tests were conducted at 700℃~800℃ on a self-assembled battery evaluation device. The measured voltage-current density curves are shown in [reference needed]. Figure 5 .

[0053] Example 1:

[0054] The preparation method of the oxygen electrode for a solid oxide electrolytic cell includes the following steps:

[0055] (1) Synthesis of La using the ammonium citrate method 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0056] Prepare La solutions with a molar concentration of 0.5 mol / L. 3+ 、Sr 2+ Mn 3+ The nitrate solution was accurately weighed and transferred at a ratio of 4:1:5 to obtain La. 3+ 、Sr 2+ Mn 3+ A nitrate solution was placed in a 500 ml beaker. The mixture was heated and stirred at 60°C for 20 minutes to obtain a mixed La. 3+ 、Sr 2+ Mn 3+ The solution was prepared using nitrate solution. Ammonium citrate (analytical grade) was added at a molar ratio of 1.5:1 to metal ions. The pH of the solution was adjusted to 8 with ammonia (analytical grade) to make it clear and transparent. The solution was then heated at 70°C with stirring to evaporate the solvent until it became gel-like. The solution was poured into a 1000ml evaporating dish and heated in an electric furnace to allow the system to self-propagate and burn, yielding a fluffy powder. The collected initial powder was calcined in a muffle furnace at 1000°C for 6 hours, ground, and passed through an 180-mesh steel sieve to obtain La. 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0057] (2)La0.8 Sr 0.2 MnO 3-δ Preparation of YSZ oxygen electrode

[0058] The La prepared in (1) 0.8 Sr 0.2 MnO 3-δ Anode powder and YSZ powder (8% Y2O3-stabilized ZrO2, Tosho, Japan) were mixed in a 3:2 ratio. Ethanol was added and the mixture was ground until homogeneous. The solvent was then dried under a heat lamp, and the mixture was transferred to a mortar and ground through a 180-mesh steel sieve. 40 wt% of auxiliary components (including pore-forming starch, dispersant fish oil, binder polyvinyl butyral 79, and solvent terpineol) were added. 0.0080 g of the mixture was coated onto a cathode-supported semi-electrolytic cell sheet using a slurry coating method. The resulting product was then sintered in a muffle furnace at 1000°C for 3 hours to obtain La. 0.8 Sr 0.2 MnO 3-δ -YSZ oxygen electrode.

[0059] (3) Impregnation solution Ce 0.87 Co 0.13 O 2-δ Preparation

[0060] Weigh 39.455g Ce(NO3)3·6H2O and 2.939g Co(NO3)2·6H2O (analytical grade) into a beaker, add deionized water, and stir until completely dissolved. Then add citric acid (citric acid:cation molar ratio 0.5), adding 9.697g citric acid (analytical grade). Adjust the pH of the solution to 1 with nitric acid (analytical grade) until the solution becomes clear and transparent. Make up the volume in a 100ml volumetric flask. 0.87 Co 0.13 O 2-δ The concentration is 1 mol / L.

[0061] (4) LSM-YSZ-2.3wt%Ce 0.87 Co 0.13 O 2-δ Oxygen electrode preparation

[0062] Take 1.2 μL of the Ce prepared in step (3) using a micro-syringe. 0.87 Co 0.13 O 2-δ Solution injected into La 0.8 Sr 0.2 MnO 3-δ-YSZ oxygen electrode surface, vacuum impregnated, calcined at 800℃ for 3h to allow the impregnation solution to penetrate into the anode interior, impregnating the oxygen electrode surface and micropores, ultimately yielding LSM-YSZ-2.3wt%Ce 0.87 Co 0.13 O 2-δ Oxygen electrode.

[0063] (5) SOEC test: Electrolysis tests were conducted at 700℃~800℃ on a self-assembled battery evaluation device. The measured voltage-current density curves are shown in [reference needed]. Figure 5 .

[0064] Figure 1 Ce was displayed 0.87 Co 0.13 O 2-δ LSM-YSZ and LSM-YSZ-Ce 0.87 Co 0.13 O 2-δ X-ray diffraction; by Figure 1 It can be seen that for Ce 0.87 Co 0.13 O 2-δ The sample showed that all diffraction patterns pointed to a cubic fluorite structure, and no CoO was observed. x Diffraction analysis indicates that Co can be incorporated into the CeO2 lattice to form a solid solution or be well dispersed on the surface. For LSM-YSZ-Ce... 0.87 Co 0.13 O 2-δ The XRD pattern of the sample. Besides the typical lines of the LSM, YSZ, and CeM phases, no other diffraction patterns were observed, indicating that Ce... 0.87 Co 0.13 O 2-δ Compatible with LSM and YSZ.

[0065] Example 2:

[0066] The preparation method of the oxygen electrode for a solid oxide electrolytic cell includes the following steps:

[0067] (1) Synthesis of La using the ammonium citrate method 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0068] Prepare La solutions with a molar concentration of 0.5 mol / L. 3+ 、Sr 2+ Mn 3+ The nitrate solution was accurately weighed and transferred at a ratio of 4:1:5 to obtain La. 3+ 、Sr 2+ Mn 3+A nitrate solution was placed in a 500 ml beaker. The mixture was heated and stirred at 60°C for 20 minutes to obtain a mixed La. 3+ 、Sr 2+ Mn 3+ The solution was prepared using nitrate solution. Ammonium citrate (analytical grade) was added at a molar ratio of 1.5:1 to metal ions. The pH of the solution was adjusted to 8 with ammonia (analytical grade) to make it clear and transparent. The solution was then heated at 70°C with stirring to evaporate the solvent until it became gel-like. The solution was poured into a 1000ml evaporating dish and heated in an electric furnace to allow the system to self-propagate and burn, yielding a fluffy powder. The collected initial powder was calcined in a muffle furnace at 1000°C for 6 hours, ground, and passed through an 180-mesh steel sieve to obtain La. 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0069] (2)La 0.8 Sr 0.2 MnO 3-δ Preparation of YSZ oxygen electrode

[0070] The La prepared in (1) 0.8 Sr 0.2 MnO 3-δ Anode powder and YSZ powder (8% Y2O3-stabilized ZrO2, Tosho, Japan) were mixed in a 3:2 ratio. Ethanol was added and the mixture was ground until homogeneous. The solvent was then dried under a heat lamp, and the mixture was transferred to a mortar and ground through a 180-mesh steel sieve. 40 wt% of auxiliary components (including pore-forming starch, dispersant fish oil, binder polyvinyl butyral 79, and solvent terpineol) were added. 0.0080 g of the mixture was coated onto a cathode-supported semi-electrolytic cell sheet using a slurry coating method. The resulting product was then sintered in a muffle furnace at 1000°C for 3 hours to obtain La. 0.8 Sr 0.2 MnO 3-δ -YSZ oxygen electrode.

[0071] (3) Impregnation solution Ce 0.87 Co 0.13 O 2-δ Preparation

[0072] Weigh 39.455g Ce(NO3)3·6H2O and 2.939g Co(NO3)2·6H2O (analytical grade) into a beaker, add deionized water, and stir until completely dissolved. Then add citric acid (citric acid:cation molar ratio 0.5), adding 9.697g citric acid (analytical grade). Adjust the pH of the solution to 1 with nitric acid (analytical grade) until the solution becomes clear and transparent. Make up the volume in a 100ml volumetric flask. 0.87 Co 0.13 O2-δ The concentration is 1 mol / L.

[0073] (4) LSM-YSZ-4.3wt%Ce 0.87 Co 0.13 O 2-δ Oxygen electrode preparation

[0074] Take 2.1 μL of the Ce prepared in step (3) using a micro-syringe. 0.87 Co 0.13 O 2-δ Solution injected into La 0.8 Sr 0.2 MnO 3-δ -YSZ oxygen electrode surface, vacuum impregnated, calcined at 800℃ for 3h to allow the impregnation solution to penetrate into the anode interior, impregnating the oxygen electrode surface and micropores, ultimately yielding LSM-YSZ-4.3wt%Ce 0.87 Co 0.13 O 2-δ Oxygen electrode.

[0075] (5) SOEC test: Electrolysis tests were conducted at 700℃~800℃ on a self-assembled battery evaluation device. The measured voltage-current density curves are shown in [reference needed]. Figure 5 .

[0076] Example 3:

[0077] The preparation method of the oxygen electrode for a solid oxide electrolytic cell includes the following steps:

[0078] (1) Synthesis of La using the ammonium citrate method 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0079] Prepare La solutions with a molar concentration of 0.5 mol / L. 3+ 、Sr 2+ Mn 3+ The nitrate solution was accurately weighed and transferred at a ratio of 4:1:5 to obtain La. 3+ 、Sr 2+ Mn 3+ A nitrate solution was placed in a 500 ml beaker. The mixture was heated and stirred at 60°C for 20 minutes to obtain a mixed La. 3+ 、Sr 2+ Mn 3+The solution was prepared using nitrate solution. Ammonium citrate (analytical grade) was added at a molar ratio of 1.5:1 to metal ions. The pH of the solution was adjusted to 8 with ammonia (analytical grade) to make it clear and transparent. The solution was then heated at 70°C with stirring to evaporate the solvent until it became gel-like. The solution was poured into a 1000ml evaporating dish and heated in an electric furnace to allow the system to self-propagate and burn, yielding a fluffy powder. The collected initial powder was calcined in a muffle furnace at 1000°C for 6 hours, ground, and passed through an 180-mesh steel sieve to obtain La. 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0080] (2)La 0.8 Sr 0.2 MnO 3-δ Preparation of YSZ oxygen electrode

[0081] The La prepared in (1) 0.8 Sr 0.2 MnO 3-δ Anode powder and YSZ powder (8% Y2O3-stabilized ZrO2, Tosho, Japan) were mixed in a 3:2 ratio. Ethanol was added and the mixture was ground until homogeneous. The solvent was then dried under a heat lamp, and the mixture was transferred to a mortar and ground through a 180-mesh steel sieve. 40 wt% of auxiliary components (including pore-forming starch, dispersant fish oil, binder polyvinyl butyral 79, and solvent terpineol) were added. 0.0080 g of the mixture was coated onto a cathode-supported semi-electrolytic cell sheet using a slurry coating method. The resulting product was then sintered in a muffle furnace at 1000°C for 3 hours to obtain La. 0.8 Sr 0.2 MnO 3-δ -YSZ oxygen electrode.

[0082] (3) Impregnation solution Ce 0.87 Co 0.13 O 2-δ Preparation

[0083] Weigh 39.455g Ce(NO3)3·6H2O and 2.939g Co(NO3)2·6H2O (analytical grade) into a beaker, add deionized water, and stir until completely dissolved. Then add citric acid (citric acid:cation molar ratio 0.5), adding 9.697g citric acid (analytical grade). Adjust the pH of the solution to 1 with nitric acid (analytical grade) until the solution becomes clear and transparent. Make up the volume in a 100ml volumetric flask. 0.87 Co 0.13 O 2-δ The concentration is 1 mol / L.

[0084] (4) LSM-YSZ-6.9wt%Ce 0.87 Co0.13 O 2-δ Oxygen electrode preparation

[0085] Use a micro-injector to take 4 μL of the Ce prepared in step 3 (3). 0.87 Co 0.13 O 2-δ Solution injected into La 0.8 Sr 0.2 MnO 3-δ The surface of the -δ-YSZ oxygen electrode was vacuum impregnated, and then calcined at 800℃ for 3 hours to allow the impregnation solution to penetrate into the anode. The impregnation solution permeated the surface of the oxygen electrode and the micropores, ultimately yielding LSM-YSZ-6.9wt%Ce. 0.87 Co 0.13 O 2-δ Oxygen electrode.

[0086] (5) SOEC test: Electrolysis tests were conducted at 700℃~800℃ on a self-assembled battery evaluation device. The measured voltage-current density curves are shown in [reference needed]. Figure 5 .

[0087] Example 4:

[0088] The preparation method of the oxygen electrode for a solid oxide electrolytic cell includes the following steps:

[0089] (1) Synthesis of La using the ammonium citrate method 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0090] Prepare La solutions with a molar concentration of 0.5 mol / L. 3+ 、Sr 2+ Mn 3+ The nitrate solution was accurately weighed and transferred at a ratio of 4:1:5 to obtain La. 3+ 、Sr 2+ Mn 3+ A nitrate solution was placed in a 500 ml beaker. The mixture was heated and stirred at 60°C for 20 minutes to obtain a mixed La. 3+ 、Sr 2+ Mn 3+ The solution was prepared using nitrate solution. Ammonium citrate (analytical grade) was added at a molar ratio of 1.5:1 to metal ions. The pH of the solution was adjusted to 8 with ammonia (analytical grade) to make it clear and transparent. The solution was then heated at 70°C with stirring to evaporate the solvent until it became gel-like. The solution was poured into a 1000ml evaporating dish and heated in an electric furnace to allow the system to self-propagate and burn, yielding a fluffy powder. The collected initial powder was calcined in a muffle furnace at 1000°C for 6 hours, ground, and passed through an 180-mesh steel sieve to obtain La. 0.8 Sr 0.2 MnO 3-δAnode powder.

[0091] (2)La 0.8 Sr 0.2 MnO 3-δ Preparation of YSZ oxygen electrode

[0092] The La prepared in (1) 0.8 Sr 0.2 MnO 3-δ Anode powder and YSZ powder (8% Y2O3-stabilized ZrO2, Tosho, Japan) were mixed in a 3:2 ratio. Ethanol was added and the mixture was ground until homogeneous. The solvent was then dried under a heat lamp, and the mixture was transferred to a mortar and ground through a 180-mesh steel sieve. 40 wt% of auxiliary components (including pore-forming starch, dispersant fish oil, binder polyvinyl butyral 79, and solvent terpineol) were added. 0.0080 g of the mixture was coated onto a cathode-supported semi-electrolytic cell sheet using a slurry coating method. The resulting product was then sintered in a muffle furnace at 1000°C for 3 hours to obtain La. 0.8 Sr 0.2 MnO 3-δ -YSZ oxygen electrode.

[0093] (3) Impregnation solution Ce 0.87 Co 0.13 O 2-δ Preparation

[0094] Weigh 39.455g Ce(NO3)3·6H2O and 2.939g Co(NO3)2·6H2O (analytical grade) into a beaker, add deionized water, and stir until completely dissolved. Then add citric acid (citric acid:cation molar ratio 0.5), adding 9.697g citric acid (analytical grade). Adjust the pH of the solution to 1 with nitric acid (analytical grade) until the solution becomes clear and transparent. Make up the volume in a 100ml volumetric flask. 0.87 Co 0.13 O 2-δ The concentration is 1 mol / L.

[0095] (4) LSM-YSZ-7.8wt%Ce 0.87 Co 0.13 O 2-δ Oxygen electrode preparation

[0096] Take 3.8 μL of Ce prepared in (3) using a micro-injector. 0.87 Co 0.13 O 2-δ Solution injected into La 0.8 Sr 0.2 MnO 3-δ-YSZ oxygen electrode surface, vacuum impregnated, calcined at 800℃ for 3h to allow the impregnation solution to penetrate into the anode interior, impregnating the oxygen electrode surface and micropores, ultimately yielding LSM-YSZ-7.8wt% Ce. 0.87 Co 0.13 O 2-δ Oxygen electrode.

[0097] (5) SOEC test: Electrolysis tests were conducted at 700℃~800℃ on a self-assembled battery evaluation device. The measured voltage-current density curves are shown in [reference needed]. Figure 5 .

[0098] LSM-YSZ-2.3wt%Ce at 800℃ 0.87 Co 0.13 O 2-δ LSM-YSZ-4.3wt%Ce 0.87 Co 0.13 O 2-δ LSM-YSZ-6.9wt%Ce 0.87 Co 0.13 O 2-δ and LSM-YSZ-7.8wt%Ce 0.87 Co 0.13 O 2-δ The current densities at the anode at 1.3V were -0.63, -0.94, -1.14, and -1.26 A / cm, respectively. -2 These are LSM-YSZ electrodes (-0.38A cm⁻¹). -2 The concentrations were 1.7, 2.5, 3.0, and 3.3 times that of the impregnation solution. This indicates the addition of Ce... 0.87 Co 0.13 O 2-δ It can effectively improve the electrochemical performance of the electrolytic cell, and within the range of 1%-10% impregnation amount, the improvement effect of the electrochemical performance of the electrolytic cell is more obvious as the impregnation solution content increases.

[0099] The SEM image of the oxygen electrode cross-section shows that Figure 2 , Figure 3 , Figure 4 It showed LSM-YSZ, LSM-YSZ-6.9wt% Ce 0.87 Co 0.13 O 2-δ and LSM-YSZ-7.8wt%Ce 0.87 Co 0.13 O 2-δ Photomicrographs. For example... Figure 2 As shown, in the LSM-YSZ oxygen electrode, LSM and YSZ are uniformly distributed and in close contact. Figure 3 , Figure 4 As shown, in LSM-YSZ-Ce0.87 Co 0.13 O 2-δ In the oxygen electrode, Ce 0.87 Co 0.13 O 2-δ Nanoparticles uniformly cover the surfaces of LSM and YSZ particles. Particle size statistics show that Ce... 0.87 Co 0.13 O 2-δ The average size of the nanoparticles is approximately 30 nm.

[0100] Comparative Example 2:

[0101] (1) La was synthesized using the ammonium citrate method described above. 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0102] (2)La 0.8 Sr 0.2 MnO 3-δ -Preparation of GDC oxygen electrode

[0103] The La prepared in (1) 0.8 Sr 0.2 MnO 3-δ Anode powder and GDC powder (40% molar composition of Gd2O3-stabilized CeO2, Qingdao Tianyao New Materials Co., Ltd.) were mixed at a ratio of 3:2. Ethanol was added and the mixture was ground until homogeneous. The solvent was then dried under a heat lamp, and the mixture was transferred to a mortar and ground through a 180-mesh steel sieve. 40 wt% of auxiliary components (including pore-forming agent starch, dispersant fish oil, binder polyvinyl butyral 79, and solvent terpineol) were added. 0.0080 g of the mixture was coated onto a cathode-supported semi-electrolytic cell sheet using a slurry coating method. The resulting product was then sintered in a muffle furnace at 1000℃ for 3 hours to obtain La. 0.8 Sr 0.2 MnO 3-δ -GDC oxygen electrode.

[0104] (3) SOEC test: Electrolysis tests were conducted at 700℃~800℃ on a self-assembled battery evaluation device. At 800℃ and 1.3V, La 0.8 Sr 0.2 MnO 3-δ The current density of the GDC oxygen electrode reaches -0.42 A cm⁻¹. -2 .

[0105] Example 5:

[0106] The preparation method of the oxygen electrode for a solid oxide electrolytic cell includes the following steps:

[0107] (1) La was synthesized using the ammonium citrate method described above. 0.8 Sr 0.2 MnO 3-δ Anode powder.

[0108] (2)La 0.8 Sr 0.2 MnO 3-δ -Preparation of GDC oxygen electrode

[0109] The La prepared in (1) 0.8 Sr 0.2 MnO 3-δ Anode powder and GDC powder (40% molar composition of Gd2O3-stabilized CeO2, Qingdao Tianyao New Materials Co., Ltd.) were mixed at a ratio of 3:2. Ethanol was added and the mixture was ground until homogeneous. The solvent was then dried under a heat lamp, and the mixture was transferred to a mortar and ground through a 180-mesh steel sieve. 40 wt% of auxiliary components (including pore-forming agent starch, dispersant fish oil, binder polyvinyl butyral 79, and solvent terpineol) were added. 0.0080 g of the mixture was coated onto a cathode-supported semi-electrolytic cell sheet using a slurry coating method. The resulting product was then sintered in a muffle furnace at 1000℃ for 3 hours to obtain La. 0.8 Sr 0.2 MnO 3-δ -GDC oxygen electrode.

[0110] (3) Impregnation solution Pr 0.89 Co 0.11 O 2-δ Preparation

[0111] Weigh 39.099g of Pr(NO3)3·6H2O and 3.234g of Co(NO3)2·6H2O (analytical grade) into a beaker, add deionized water, and stir until completely dissolved. Then add citric acid (citric acid:cation molar ratio 0.5), adding 9.697g of citric acid (analytical grade). Adjust the pH of the solution to 1 with nitric acid (analytical grade) until the solution becomes clear and transparent. Make up the volume in a 100ml volumetric flask. 0.89 Co 0.11 O 2-δ The concentration is 1 mol / L.

[0112] (4) LSM-GDC-Pr with different impregnation amounts 0.89 Co 0.11 O 2-δ Oxygen electrode preparation

[0113] Take 1.1 μL, 2.4 μL, 3.7 μL, 4.5 μL, and 5.8 μL of the Pr prepared in step (3) using a micro-syringe. 0.89 Co 0.11 O2-δ Solution injected into La 0.8 Sr 0.2 MnO 3-δ - The surface of the GDC oxygen electrode is vacuum impregnated and calcined at 700–1000℃ for 3 hours to allow the impregnation solution to penetrate into the anode. The impregnation solution impregnates the surface of the oxygen electrode and the micropores, ultimately yielding LSM-GDC-2.1wt% Pr. 0.89 Co 0.11 O 2-δ LSM-GDC-4.5wt%Pr 0.89 Co 0.11 O 2-δ LSM-GDC-7.0wt%Pr 0.89 Co 0.11 O 2-δ LSM-GDC-8.3wt%Pr 0.89 Co 0.11 O 2-δ LSM-GDC-10.5wt%Pr 0.89 Co 0.11 O 2-δ Five oxygen electrodes with different impregnation amounts.

[0114] (5) SOEC Test: The five electrolytic cell sheets with different impregnation amounts obtained in (4) were subjected to electrolytic testing at 700℃~800℃ on a self-assembled battery evaluation device. At 800℃, LSM-GDC-2.1wt%Pr 0.89 Co 0.11 O 2-δ LSM-GDC-4.5wt%Pr 0.89 Co 0.11 O 2-δ LSM-GDC-7.0wt%Pr 0.89 Co 0.11 O 2-δ LSM-GDC-8.3wt%Pr 0.89 Co 0.11 O 2-δ LSM-GDC-10.5wt%Pr 0.89 Co 0.11 O 2-δ The current densities at the anode at 1.3V were -0.67, -0.97, -1.22, -1.30, and -1.18 A / cm, respectively. -2 These are LSM-GDC electrodes (-0.42A cm⁻¹). -2 The concentrations were 1.6, 2.3, 2.9, 3.1, and 2.8 times that of the impregnation solution Pr. 0.89 Co 0.11 O 2-δIt can effectively improve the electrochemical performance of electrolytic cells, and within a certain range, the improvement effect is more obvious with the increase of impregnation solution content. When the impregnation amount exceeds 10wt%, the current density of the resulting electrolytic cell decreases.

[0115] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An oxygen electrode for a solid oxide electrolytic cell, characterized in that, Its composition includes LSM-YSZ-A x Co 1-x O 2-δ Or LSF-YSZ-A x Co 1-x O 2-δ Or LSM-GDC-A x Co 1-x O 2-δ Or LSF-GDC-A x Co 1-x O 2-δ Where 0.1≤x≤0.9, δ represents the oxygen deficiency value; The A x Co 1-x O 2-δ In this context, A is one or more of Ce, Pr, Nd, Sm, Gd, and Yb; the chemical formula of the LSM is La. x Sr 1- x MnO 3-δ , 0.1≤x≤0.9; LSF chemical formula is La x Sr 1-x FeO 3-δ , 0.1≤x≤0.9; The chemical formula of YSZ is Y x Zr 1-x O2, 0.1≤x≤0.9; GDC chemical formula is Gd x Ce 1-x O2, 0.1≤x≤0.9; The A x Co 1-x O 2-δ The average particle size of the nanoparticles is 20~40nm; the molar ratio of the A and Co metal ions is 0.1~10:

1.

2. The oxygen electrode for a solid oxide electrolytic cell according to claim 1, characterized in that, The thickness of the oxygen electrode in the solid oxide electrolytic cell is 10~50μm.

3. The method for preparing the oxygen electrode of the solid oxide electrolytic cell according to claim 1, characterized in that, Includes the following steps: S1. Prepare LSM-YSZ or LSF-YSZ or LSM-GDC or LSF-GDC oxygen electrodes; S2. Prepare A at a concentration of 0.3~1mol / L. x Co 1-x O 2-δ Solution: According to chemical formula A x Co 1-x O 2-δ Weigh out nitrate powder and cobalt nitrate powder of A, dissolve them in water, and add a complexing agent in a molar amount of 0.25 to 2.5 times the total metal ions; heat and stir at 60 to 90°C for 2 to 10 hours, and adjust the pH of the solution to ≥ 8 after dissolution. S3, Impregnation and roasting: The oxygen electrode from step S1 is impregnated with the solution prepared in step S2, 1 to 5 times, and then calcined at 700 to 1000°C for 3 to 4 hours to obtain the final product. The A x Co 1-x O 2-δ The impregnation amount is 1 wt% to 15 wt% of the mass of the LSM-YSZ, LSF-YSZ, LSM-GDC, or LSF-GDC oxygen electrode.

4. The method for preparing the oxygen electrode of the solid oxide electrolytic cell according to claim 3, characterized in that, The preparation method of the oxygen electrode in step S1 includes the following steps: (1) Preparation of anode powder: According to the chemical formula La of LSM x Sr 1-x MnO 3-δ Or the chemical formula of LSF, La x Sr 1-x FeO 3-δ Weigh out the metal ion nitrate powder, dissolve it in water, add a complexing agent in a molar amount of 0.25 to 2.5 times the total metal ions, heat and stir at 60 to 90°C for 15 to 20 minutes, adjust the pH of the solution to ≤ 1 after dissolution, and continue to evaporate at 60 to 90°C until the solution becomes a transparent gel-like liquid. The gel-like substance is heated at 200~500℃ for 10~30 minutes until it self-propagates and forms a fluffy powder, thus obtaining the primary powder; the primary powder is LSM primary powder or LSF primary powder. The primary powder is calcined at 700~1000℃ for 5~10h, and then ground through a 180-mesh steel sieve to obtain secondary powder; the secondary powder is LSM secondary powder or LSF secondary powder. The secondary powder is mixed with YSZ or GDC powder, solvent A is added and mixed evenly, the solvent is dried and then ground, and the mixture is passed through a 180-mesh steel sieve to obtain the mixed powder; the solvent A is one or more of ethanol, terpineol, and n-butanol. (2) Preparation of anode slurry: The mixed powder obtained in step (1) is added to the auxiliary components and solvent B, and after being fully ground, it is coated onto a cathode-supported semi-electrolytic cell sheet or an electrolyte-supported semi-electrolytic cell sheet and air-dried to obtain a semi-electrolytic cell sheet; the auxiliary components are pore-forming agent, dispersant and binder; the solvent B is one or more of terpineol, toluene and ethanol. (3) Roasting: The semi-electrolytic cell sheet obtained in step (2) is calcined at 800~1000℃ for 3~5h to obtain the oxygen electrode described in step S1.

5. The preparation method according to claim 4, characterized in that, The mass ratio of the secondary powder to YSZ or GDC powder is 1:2 to 2:1; the mass ratio of the mixed powder to the auxiliary components is 1:2 to 2:

1.

6. The preparation method according to claim 4, characterized in that, The auxiliary materials contain 5-20 wt% pore-forming agent, 1-5 wt% dispersant, and 5-20 wt% binder; the pore-forming agent is any one of starch, corn flour, and polymethyl methacrylate; the dispersant is fish oil; and the binder is ethyl cellulose or polyvinyl butyral 79; the solvent B accounts for 60-90 wt% of the anode slurry.

7. The preparation method according to claim 3 or 4, characterized in that, The complexing agent is any one of ammonium citrate, glycine, urea, EDTA, and citric acid.

8. The preparation method according to claim 4, characterized in that, In the cathode-supported semi-electrolytic cell sheet, the cathode support layer is made of Ni-YSZ or Ni-GDC; in the electrolyte-supported semi-electrolytic cell sheet, the electrolyte support layer is made of YSZ or GDC.

9. The preparation method according to claim 4, characterized in that, The cathode-supported semi-electrolytic cell sheet or the electrolyte-supported semi-electrolytic cell sheet is prepared by casting, calendering, or dry pressing of powder.

10. The method for preparing the oxygen electrode of the solid oxide electrolytic cell according to claim 3, characterized in that, The impregnation method in step S3 is vacuum impregnation. The A x Co 1-x O 2-δ The impregnation amount is 7-11 wt% of the mass of the LSM-YSZ, LSF-YSZ, LSM-GDC, or LSF-GDC oxygen electrode.

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