High-entropy double perovskite type direct ammonia solid oxide fuel cell anode material, and preparation method and application thereof

Abstract

This invention belongs to the field of solid oxide fuel cell technology, specifically relating to a method for preparing and applying a highly catalytically active and stable high-entropy double perovskite direct ammonia solid oxide fuel cell anode. The anode material is characterized by having the general chemical formula Sr₂Fe₃. x Sn y Co y Nb y Zr y Mo z O 6‑δ Wherein, 0.75≤x≤1, 0.15≤y≤0.25, 0.25≤z≤0.4, 0≤δ≤1, and δ represents the oxygen vacancy content. The material of this invention exhibits excellent catalytic activity and outstanding stability, effectively solving the Sr₂Fe₂O₃ problem. 1.5 Mo 0.5 O6 anode material exhibits structural instability at high temperatures (above 800℃) and tends towards perovskite-like Sr3FeMoO2. 6.5 The problem of transformation. The material of this invention and the electrolyte material La. 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 The material exhibits good chemical compatibility, and solid oxide fuel cells fabricated using this invention demonstrate excellent electrochemical performance and superior long-term stability under both H2 and NH3 conditions. The material is simple to prepare, possesses excellent performance, and has broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide fuel cell technology, and relates to a method for preparing a high-entropy double perovskite anode material and its application in ammonia fuel solid oxide fuel cells. Background Technology

[0002] Among numerous new energy technologies, solid oxide fuel cells (SOFCs) can directly convert chemical energy into electrical energy, avoiding the energy losses caused by multiple conversions in traditional energy sources. Furthermore, their advantages such as high efficiency, low emissions, and fuel versatility have gradually made them stand out in the new energy field. Although hydrogen (H2) has broad application prospects as a clean energy source, it faces many challenges in storage and transportation. Therefore, in recent years, nitrogen dioxide (NH3) has gradually become an emerging alternative to H2 due to its advantages such as low cost, convenient transportation, high energy density, and carbon-free properties. This trend has led to significant attention being paid to research on new energy materials in the H2 and NH3 fields.

[0003] Anode materials, as a core component of SOFCs, play a crucial role in the battery's efficiency, catalytic performance, and stability. Traditional nickel-based cermet anodes are prone to phase transitions, corrosion, and nitride deposition during long-term operation in NH3, which affects the interfacial contact between the anode and electrolyte, significantly reducing the catalytic activity of the anode. Therefore, developing nitridation-resistant, structurally stable, and highly catalytically active solid oxide fuel cell anode materials is of great significance. In recent years, high-entropy oxides (HEOs) have attracted widespread attention in the fuel cell field due to their unique structure and properties. As a novel functional material, HEOs exhibit excellent catalytic activity and good structural stability at high temperatures and in reducing atmospheres due to their multi-element synergistic effects, providing a new approach to solving the problems of traditional perovskite anode materials in ammonia-fueled SOFCs. Extensive experimental research and data verification by predecessors have demonstrated that Sr₂Fe 1.5 Mo 0.5 O 6-δ (SFM) double perovskite anode materials exhibit excellent conductivity and electrochemical performance under reducing atmospheres, but research on high-entropy SFM series materials under NH3 atmospheres is almost nonexistent. The material of this invention possesses a stable cubic perovskite phase structure under both H2 and NH3 atmospheres. Solid oxide fuel cells prepared using this material exhibit good electrochemical performance and long-term stability under both H2 and NH3 atmospheres, effectively mitigating the degradation of anode electrochemical performance and providing some resistance to corrosion and nitride deposition. Summary of the Invention

[0004] One of the objectives of this invention is to provide a high-entropy double perovskite solid oxide fuel cell anode material with high catalytic activity and stability.

[0005] The second objective of this invention is to provide a method for preparing the above-mentioned anode material and its application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a high-entropy double perovskite anode material, wherein the chemical formula of the material is Sr2Fe x Sn y Co y Nb y Zr y Mo z O 6-δ Where 0.75≤x≤1, 0.15≤y≤0.25, 0.25≤z≤0.4, 0≤δ≤1, and δ is the oxygen vacancy content.

[0007] The present invention also provides a method for preparing the above-mentioned anode material, specifically including the following steps:

[0008] (1) According to the chemical formula Sr2Fe x Sn y Co y Nb y Zr y Mo z O 6-δ Weigh out the corresponding stoichiometric ratios of the metal elements in the sample containing Mo. 6+ Ammonium molybdate, containing Sr 2+ Fe 3+ Co 2+ Zr 4+ Nitrates, containing Nb 5+ Niobium oxalate and Sn 2+ Chlorides;

[0009] (2) Dissolve glycine and citric acid sequentially in a beaker containing an appropriate amount of deionized water and heat at 60-90℃. Place the weighed drugs obtained in step (1) sequentially into the beaker and stir continuously to obtain a fully dissolved and clear solution. Then increase the heating temperature to 120-160℃ until the solution forms a gel. Transfer the resulting gel to an oven and use the high temperature of 200-300℃ in the oven to cause the gel to spontaneously combust and form a fluffy powder.

[0010] (3) Grind the fluffy powder obtained in step (2) with a mortar and pestle, and then put it into a muffle furnace and pre-fire it at 700-900℃ for 6-10 hours;

[0011] (4) Grind the powder after pre-calcination in step (3) again, weigh a certain amount and put it into a mold, and press it into a round disc with a pressure of 2-4 MPa.

[0012] (5) Place the pressed discs from step (4) into a tube furnace and sinter them at 1050-1150℃ for 8-12 hours in a reducing atmosphere.

[0013] (6) Place the sintered disc from step (5) into a mortar, add anhydrous ethanol and wet grind, then bake the powder dry to obtain Sr2FeSn. 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Solid oxide fuel cell anode electrode powder;

[0014] Preferably, the product containing Mo used in step (1) 6+ Ammonium molybdate is H 24 Mo7N6O 24 ·4H2O, containing Sr 2+ Fe 3+ Co 2+ Zr 4+ The nitrates are Sr(NO3)2, Fe(NO3)3·9H2O, Co(NO3)2·6H2O and Zr(NO3)4·5H2O, containing Nb 5+ Niobium oxalate is C 10 H5NbO 20 Contains Sn 2+ The chloride is SnCl2·2H2O.

[0015] Preferably, the ratio of the number of moles of glycine and citric acid weighed in step (2) to the total number of moles of metal ions is (1-3):(1-2):(0.5-1.5); the C in the weighed drug is obtained 10 H5NbO 20 Zr(NO3)4·5H2O need to be dissolved separately in water baths at 30-50℃ and 50-70℃, respectively.

[0016] Preferably, the reducing atmosphere in step (5) needs to be 8 ml / min. -1 A continuous flow rate of 5% H2 / Ar is introduced.

[0017] This invention also provides a solid oxide fuel cell prepared using a high-entropy double perovskite anode material, characterized by the following steps:

[0018] (1) Weigh a certain amount of the Sr2FeSn prepared above. 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δSolid oxide fuel cell anode electrode powder is placed in a mortar, a certain amount of binder is added, and the mixture is ground to obtain a battery anode slurry;

[0019] (2) Weigh a certain amount of SmBaCo2O 5+δ Cathode powder is placed in a mortar, a certain amount of binder is added, and the mixture is ground to obtain battery cathode slurry;

[0020] (3) The electrode paste obtained in steps (1) and (2) above is uniformly coated onto the electrolyte sheet La using screen printing. 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 Both sides were dried with a heat lamp to obtain a full battery cell;

[0021] (4) Place the full cell obtained in step (3) in a high-temperature tube furnace and calcine it at 900-1100℃ for 2-4 hours under N2 to obtain Sr2FeSn 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Solid oxide fuel cells with anode material.

[0022] Preferably, the Sr2FeSn used in step (1) 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ The mass ratio of anode powder to binder is (1.1-1.3):(1.5-1.7); the binder is prepared by mixing ethyl cellulose and terpineol in a mass ratio of (0.8-1.2):(7.2:10.8).

[0023] Preferably, the thickness of the electrolyte sheet used in step (3) is 0.3 mm.

[0024] This invention provides a highly catalytically active and stable high-entropy double perovskite anode material for ammonia SOFCs, its preparation, and its application. The chemical formula of the anode material is Sr₂Fe₃. x Sn y Co y Nb y Zr y Mo z O 6-δ , with electrolyte La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85It exhibits good chemical compatibility and a stable cubic perovskite phase structure under H2. Sr2Fe 1.5 Mo 0.5 O6-based double perovskite materials exhibit excellent electrical and electrochemical properties, but these materials are reduced to the high-resistivity phase Sr3FeMoO at high temperatures (above 800°C). 6.5 This results in lower catalytic activity under H2 and NH3 atmospheres. The present invention utilizes Sr2Fe... 1.5 Mo 0.5 Based on O6 material, the catalytic performance and thermal stability of the material were significantly improved by the high-entropy doping strategy at the B site. Furthermore, the solid oxide fuel cell prepared with this high-entropy material exhibited excellent electrochemical performance and resistance to nitride deposition.

[0025] The results of the examples show that, using the high-entropy double perovskite ammonia SOFC anode material provided by this invention, XRD characterization reveals that the material synthesized under a 5% H2 / Ar atmosphere exhibits Fe-Co nanoparticle desolvation, and retains a stable cubic perovskite phase structure after H2 reduction; the solid oxide fuel cell prepared with the anode material provided by this invention uses Sr2FeSn 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ As the anode, the peak power densities at 850℃ in H2 and NH3 are 834 mW / cm³, respectively. -2 and 535mW cm -2 It operated stably at 750℃ for 200 hours and 60 hours under H2 and NH3 conditions, respectively, with a voltage decay rate of only 0.0002 V h. -1 This demonstrates that the material possesses excellent electrochemical performance and good long-term stability. Attached Figure Description

[0026] Figure 1 Sr2FeSn synthesized in 5% H2 / Ar 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ XRD pattern.

[0027] Figure 2 Sr2FeSn after H2 reduction 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ XRD pattern.

[0028] Figure 3 The material Sr2FeSn of this invention 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Power density diagram of a full cell fabricated using the anode material in an H2 atmosphere.

[0029] Figure 4 The material Sr2FeSn of this invention 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Power density diagram of a full cell fabricated using an anode material in an NH3 atmosphere.

[0030] Figure 5 The material Sr2FeSn of this invention 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ A graph showing the long-term stability test of a full cell made with the anode material in an H2 atmosphere.

[0031] Figure 6 The material Sr2FeSn of this invention 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ A graph showing the long-term stability test of a full cell made with an anode material under an NH3 atmosphere. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to specific examples. The specific embodiments described are only used to explain the present invention, and the implementation of the present invention is not limited to the following examples.

[0033] This example provides a high-entropy dual perovskite solid oxide fuel cell Sr2FeSn. 0.15 Co 0.15 Nb 0.15 Zr 0.1 5Mo 0.4 O 6-δ The preparation method of the anode material specifically includes the following steps:

[0034] (1) H 24 Mo7N6O 24·4H2O, Sr(NO3)2, Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Zr(NO3)4·5H2O, C 10 H5NbO 20 Weigh the raw materials in a molar ratio of 0.06:2:1:0.15:0.15:0.15:0.15;

[0035] (2) Dissolve glycine (twice the total molar amount of metal ions) in a beaker containing 250 ml of deionized water and place it in a 70°C water bath. After the solution becomes clear, add citric acid (1.5 times the total molar amount of metal ions). Add the weighed reagent from step (1) to the beaker every 15 minutes (the amount of C in the weighed reagent...). 10 H5NbO 20 Zr(NO3)4·5H2O needs to be dissolved separately in water baths at 40℃ and 60℃ respectively. Continue stirring to obtain a fully dissolved and clear solution. Then, adjust the heating and stirring table to 140℃ to evaporate the solvent until a gel forms. Quickly place the gel in an oven and set the temperature to 250℃, waiting for the gel to spontaneously combust and form a fluffy powder.

[0036] (3) After grinding the powder obtained in step (2) in a mortar, collect the powder into a crucible and place it in a muffle furnace, and pre-calcine it at 800°C for 8 hours in an air atmosphere;

[0037] (4) Put the powder that was pre-burned in step (3) back into the mortar and grind it thoroughly. Weigh 0.28g of the powder and put it into a circular mold with a diameter of 13mm. Press it into a disc with a pressure of 3MPa.

[0038] (5) After placing the pressed discs from step (4) into a high-temperature tube furnace, a vacuum is drawn, and the mixture is heated at 8 ml / min. -1 A continuous flow of 5% H2 / Ar gas was introduced, and then sintering was carried out at 1100℃ for 10 hours.

[0039] (6) Take out the sintered disc from step (5) and place it in a mortar. Add anhydrous ethanol and wet grind it thoroughly. Then place it under a heat lamp to dry it to obtain Sr2FeSn. 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Solid oxide fuel cell anode electrode powder;

[0040] Solid oxide fuel cells prepared using a high-entropy double perovskite SOFC anode material are characterized by the following steps:

[0041] (1) Weigh a certain amount of the Sr2FeSn obtained above.0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Solid oxide fuel cell anode electrode powder is placed in a mortar, and a certain amount of binder is added (the mass ratio of anode powder to binder is 1.2:1.6; the binder is prepared by mixing ethyl cellulose and terpineol in a mass ratio of 1:9) and ground evenly to form an anode electrode slurry.

[0042] (2) Weigh a certain amount of SmBaCo2O 5+δ The cathode powder is placed in a mortar, a certain amount of binder is added, and the mixture is ground evenly to prepare a cathode electrode slurry (SmBaCo2O). 5+δ The cathode powder was prepared by mechanical ball milling and sintering in air at 1150℃ for 12 hours.

[0043] (3) The anode paste obtained in step (1) is uniformly coated onto a 0.3 mm electrolyte sheet La using screen printing. 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 Place one side of the cathode paste on a baking lamp and bake for 10 minutes. After drying, print the cathode paste prepared in step (2) onto the other side of the electrolyte sheet using the same method. (The electrolyte sheet is prepared by mechanical ball milling. 0.28g of powder is placed in a mold with a diameter of 13mm and pressed under a pressure of 3MPa. Then, it is sintered at 1400℃ for 10h to obtain a dense electrolyte sheet.)

[0044] (4) Place the screen-printed full-cell wafers from step (3) obliquely on a boat-shaped corundum boat, place it in a high-temperature tube furnace, and perform a vacuum operation at 12 ml / min. -1 N2 was continuously introduced at a constant flow rate, followed by calcination at 1000℃ for 2 hours to obtain Sr2FeSn. 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Solid oxide fuel cells with anode material;

[0045] (5) A small amount of silver paste is coated on both the anode and cathode sides of the full cell obtained in step (4) to form a closed circuit, and a silver wire is used for current collection. Then, the full cell disc is sealed to one end of the ceramic tube with silver paste, with the cathode side facing outward. The tubular cell is placed in an oven and baked at 150°C for 2 hours. After cooling, the tubular cell is removed, and a layer of ceramic adhesive is sealed at the connection between the silver paste and the full cell disc. Finally, the tubular cell is placed at room temperature for 2 hours. The obtained battery tube is fixed in a muffle furnace, with the tail end connected to a pipe leading to the outside. The cathode and anode of the single cell are connected to the electrochemical workstation through a silver wire. Fuel gas is introduced into the anode of the solid oxide fuel cell through the ceramic tube, and the cathode side of the cell is placed in the outside air atmosphere. Direct current is generated by the loss of electrons at the cathode and the gain of electrons at the anode at high temperature, thereby realizing the conversion of chemical energy into electrical energy.

[0046] The Sr2FeSn prepared in this invention was analyzed using X-ray diffraction. 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Phase analysis of the anode material powder was performed for comparison. Figure 1 and Figure 2 Sr2Fe 1.5 Mo 0.5 The main phase structure of the O6 material changes, while the material of this invention still maintains a stable cubic perovskite phase structure and exhibits Fe-Co nanoparticle precipitation under H2 conditions, further indicating that Sr2FeSn 0.1 5Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ The material possesses excellent structural stability.

[0047] For the material Sr2FeSn of the present invention 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Electrochemical performance tests were conducted on a solid oxide fuel cell full cell fabricated using the anode material. The power density test results for the cell under H2 and NH3 conditions are as follows: Figure 3 , Figure 4 As shown, Figure 3 The material of this invention exhibits a peak power density of 834 mW / cm² at 850°C in H₂. -2 The peak power density at 850℃ in NH3 is 535 mW / cm³. -2 This demonstrates that the material of this invention has excellent electrochemical performance.

[0048] For the material Sr2FeSn of the present invention 0.15 Co 0.15 Nb 0.15 Zr 0.15 Mo 0.4 O 6-δ Long-term stability tests were conducted on a solid oxide fuel cell full cell fabricated using the anode material. The stability test results of the cell under H2 and NH3 conditions are as follows: Figure 5 , Figure 6 As shown in the figure, the material of the present invention operates stably at 750℃ under H2 and NH3 for 200h and 60h respectively, with a voltage decay rate of only 0.0002V / h. -1 This indicates that the material has excellent long-term stability and good resistance to nitride deposition.

[0049] The above description is only a preferred experimental example of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention shall be covered by the present invention.

Claims

1. A method for preparing a high-entropy double perovskite type direct ammonia solid oxide fuel cell anode material, characterized by, Sr2Fe x Sn y Co y Nb y Zr y Mo z O 6-δ wherein 0.75≤x≤1, 0.15≤y≤0.25, 0.25≤z≤0.4; 0≤δ≤1, δ is the oxygen vacancy content; the preparation method adopts the following steps: (1) Sr2Fe x Sn y Co y Nb y Zr y Mo z O 6-δ The stoichiometric ratio of each metal element is respectively taken as molybdate containing Mo 6+ , nitrate containing Sr 2+ , Fe 3+ , Co 2+ , Zr 4+ , oxalate containing Nb 5+ , and chloride containing Sn 2+ ; (2) Glycine and citric acid are sequentially dissolved in a beaker containing a proper amount of deionized water, and dissolved under the condition of heating at 60-90 ℃; the weighed medicine in step (1) is sequentially put into the beaker, and a fully dissolved clear solution is obtained by continuous stirring; then the heating temperature is increased to 120-160 ℃ until the solution forms a gel, and the obtained gel is transferred to an oven, and the gel is spontaneously combusted to form fluffy powder by high temperature of the oven; (3) The fluffy powder obtained in step (2) is ground with a mortar, and then put into a muffle furnace for pre-burning; (4) The pre-burned powder in step (3) is ground again, and a proper amount of powder is weighed and put into a mold to be pressed into a round tablet; (5) The round tablet pressed in step (4) is put into a tube furnace, and sintered under a reducing atmosphere; (6) Put the sintered disc in step (5) into a mortar, add anhydrous ethanol for wet grinding, and obtain Sr2Fe x Sn y Co y Nb y Zr y Mo z O 6-δ Solid oxide fuel cell anode powder.

2. The method of claim 1, wherein, In step (1), the Mo 6+ The chemical formula of ammonium molybdate is H. 24 Mo7N6O 24 ·4H2O, containing Sr 2+ Fe 3+ Co 2+ Zr 4+ The nitrates are Sr(NO3)2, Fe(NO3)3·9H2O, Co(NO3)2·6H2O and Zr(NO3)4·5H2O, containing Nb 5+ Niobium oxalate is C 10 H5NbO 20 Contains Sn 2+ The chloride is SnCl2·2H2O.

3. The preparation method according to claim 1, characterized in that, In step (2), the total molar number of metal ions: the molar number of glycine: the molar number of citric acid = 1: (1.5-2.5): (1-2.5), the drying temperature of the oven is 200-300 ℃, and the drying time is 4-6 h.

4. The preparation method according to claim 1, characterized in that, In step (3), the pre-burning temperature of the muffle furnace is 700-900 ℃, and the pre-burning time is 8-12 h.

5. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. In step (4), the mass of the proper amount of powder is 0.3-1 g, the diameter of the tablet grinding mold is 10-15 mm, and the oil table pressure of the tablet press is 2-5 MPa.

6. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. In step (5), the reducing atmosphere is 5% H2 / Ar, the sintering temperature is 1050-1150 ℃, and the sintering time is 8-12 h.

7. Use of a high-entropy double perovskite solid oxide fuel cell anode material prepared according to any one of claims 1 to 6, characterized in that, The high-entropy double perovskite solid oxide fuel cell anode material is used for preparing an anode in a solid oxide fuel cell.

8. Use according to claim 7, characterized in that, The solid oxide fuel cell is prepared by the following steps: (1) A certain amount of the prepared Sr2Fe x Sn y Co y Nb y Zr y Mo z O 6-δ The solid oxide fuel cell anode powder is added with a proper amount of binder composed of terpineol and ethyl cellulose in a mass ratio of 9:1 in a mortar, and is ground to obtain a cell anode slurry, wherein the mass ratio of the anode powder to the binder is 1:(1.5-2.5); (2) A certain amount of SmBaCo2O5 powder is weighed 5+δ The cathode powder is added with an appropriate amount of binder composed of terpineol and ethyl cellulose in a mass ratio of 9:1 in a mortar, and grinded to obtain a battery cathode slurry, wherein the mass ratio of the cathode powder to the binder is 1:(1.5-2.5); (3) The electrode paste prepared in the above step (1) and step (2) is uniformly coated on both sides of the electrolyte sheet La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 by screen printing method, and dried by baking lamp to obtain a full cell sheet. (4) The full battery piece obtained in step (3) is placed in a high-temperature tube furnace and calcined at 900-1100 °C for 2-4 h under N2 to obtain a Sr2Fe x Sn y Co y Nb y Zr y Mo z O 6-δ solid oxide fuel cell with the solid material as an anode material.

Images