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

Abstract

This invention belongs to the field of solid oxide fuel cell technology, and relates to a high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material, its preparation method, and its application. The anode material is characterized by having the general chemical formula SrTi. x Ta x Co x Zr x Nb x O 3‑δ Where x = 0.2, 0 ≤ δ ≤ 1, and δ represents the oxygen vacancy content. This invention synthesizes a high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material using carbonates and oxides as raw materials via high-energy ball milling, through appropriate elemental doping and sintering temperatures. Solid oxide fuel cells fabricated using this material exhibit excellent electrochemical performance and long-term stability under hydrogen and ammonia atmospheres. The material of this invention is simple to prepare, has excellent performance, and shows great application potential.

Description

Technical Field

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

[0002] Traditional fossil fuel power generation produces large amounts of greenhouse gases such as carbon dioxide, causing serious environmental impacts. Finding clean and efficient energy conversion technologies has become an urgent priority. Hydrogen energy is an ideal clean energy source, and fuel cells are one of the best ways to efficiently convert hydrogen energy into electricity. Solid oxide fuel cells (SOFCs), as the most cutting-edge, efficient, and challenging fuel cell technology to develop, have advantages such as high conversion efficiency, low carbon footprint, no need for precious metals, and flexibility in fuel types. Their energy conversion rate can reach 60%, and when used in conjunction with combined heat and power (CHP) units, the energy conversion efficiency can reach as high as 85%. In-depth exploration and development of SOFC technology is of profound significance for building a sustainable energy system, addressing global environmental challenges, and promoting the green development of human society.

[0003] Hydrogen is the most widely used anode fuel gas, offering high energy conversion efficiency and being pollution-free, but it suffers from drawbacks such as flammability, explosiveness, difficulty in transportation, and high production costs. Ammonia, on the other hand, is highly compressible, has a high hydrogen content (17.8 wt%), and boasts advantages such as low cost, availability, ease of storage, low pollution, and non-flammability and explosiveness, making it a promising hydrogen energy carrier. Therefore, developing anode materials for direct ammonia solid oxide fuel cells with high ammonia catalytic activity and high chemical stability is essential. High-entropy oxides exhibit good chemical stability, and the synergistic effect among multiple elements can effectively enhance the catalytic activity of ammonia, making them a good choice for anode materials in direct ammonia solid oxide fuel cells. Therefore, this invention develops a high-entropy perovskite anode material with excellent ammonia catalytic activity, and solid oxide fuel cells prepared using this material demonstrate good performance under both hydrogen and ammonia conditions. Summary of the Invention

[0004] One of the objectives of this invention is to provide a solid oxide fuel cell anode material with high catalytic activity and stable performance under an ammonia fuel atmosphere.

[0005] The second objective of this invention is to provide a method for preparing and applying the aforementioned high-entropy perovskite anode material.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material, characterized in that the molecular formula of the high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material is SrTi x Ta x Co x Zrx Nb x O 3-δ , where x=0.2, 0≤δ≤1, and δ is the oxygen vacancy content.

[0007] This invention also provides a method for preparing the above-mentioned high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material, specifically including the following steps:

[0008] (1) According to the chemical formula SrTi x Ta x Co x Zr x Nb x O 3-δ The stoichiometric ratio of the metal elements in the sample is determined by weighing samples containing Sr. 2 + carbonates containing Ti 4+ Oxides containing Co 3+ oxides containing Zr 4+ Oxides containing Nb 5+ oxides containing Ta 5+ Oxides;

[0009] (2) Place the raw material weighed in step (1) into a ball mill jar, add agate balls, and ball mill;

[0010] (3) Take the slurry from step (2) out of the ball mill jar, dry it, and collect the powder;

[0011] (4) The powder from step (3) is placed in a muffle furnace for pre-calcination;

[0012] (5) Place the powder that was pre-burned in step (4) into a mortar and grind it. After grinding, weigh an appropriate amount of powder and put it into a mold to press it into a sheet.

[0013] (6) Place the pressed sheet from step (5) into a high-temperature furnace for calcination;

[0014] (7) Place the calcined sample piece from step (6) into a mortar, add an appropriate amount of anhydrous ethanol for grinding, and dry the sample after thorough grinding to obtain high-entropy perovskite type direct ammonia solid oxide fuel cell anode electrode powder.

[0015] Preferably, step (1) contains Sr 2+ The carbonate is SrCO3, containing Ti 4+ The oxide is TiO2, containing Co 3+ The oxide is Co3O4, containing Zr 4+ The oxide is ZrO2, containing Nb 5+ The oxide is Nb₂O₅, containing Ta 5+The oxide is Ta2O5;

[0016] Preferably, the SrTi in step (1) x Ta x Co x Zr x Nb x O 3-δ The molar ratio of Sr, Ti, Co, Zr, Nb, and Ta in the chemical formula is 1:0.2:0.2:0.2:0.2:0.2.

[0017] Preferably, in step (2), the ratio of agate balls added to the milling jar to the sample balls is (9-11):1, and the milling time is 20-30 hours.

[0018] Preferably, the pre-firing temperature in step (4) is 900-1100℃ and the pre-firing time is 8-12h.

[0019] Preferably, in step (5), the mass of the appropriate amount of powder is 0.3-1g, the diameter of the tableting mold is 10-15mm, and the pressure of the tableting machine oil gauge is 2-5Mpa.

[0020] Preferably, the calcination temperature in step (6) is 1100-1300℃ and the calcination time is 8-12h.

[0021] Preferably, the high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material obtained by the above preparation method has the chemical formula SrTi. 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ δ is the oxygen vacancy concentration, where 0 ≤ δ ≤ 1.

[0022] This invention also provides an application of a high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material, characterized by the following steps:

[0023] (1) Weigh an appropriate amount of the high-entropy perovskite type direct ammonia solid oxide fuel cell anode electrode powder prepared above and place it in a mortar. Add a certain amount of binder and grind it evenly to make an anode electrode slurry.

[0024] (2) Weigh an appropriate amount of cathode powder and place it in a mortar, add a certain amount of binder, and grind it evenly to make a cathode electrode slurry.

[0025] (3) The electrode slurry obtained in steps (1) and (2) is uniformly coated on both sides of the electrolyte and dried to obtain a full cell.

[0026] (4) Place the dried full cell from step (3) in a high-temperature tube furnace and calcine it at 900-1000°C for 1-3 hours under N2 atmosphere to obtain a solid oxide fuel cell.

[0027] Preferably, the mass ratio of the anode powder to the binder used in step (1) is 1:(1.5-2.5); the binder is prepared by mixing terpineol and ethyl cellulose in a mass ratio of 9:1.

[0028] Preferably, the cathode powder used in step (2) is SmBaCo2O 5+δ .

[0029] Preferably, the electrolyte in step (3) is La. 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 The thickness is 0.3mm.

[0030] Preferably, the calcination temperature in step (4) is 950°C and the calcination time is 2 hours.

[0031] This invention provides a high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material, its preparation method, and its application. Chemically, the anode material has the chemical formula SrTi. 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ It has a single perovskite structure. Compatibility test results show that this anode material is compatible with the electrolyte material La. 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 It exhibits good chemical compatibility. Ti-based perovskite materials inherently possess good chemical stability and electronic conductivity, but their catalytic activity towards fuel gas is relatively insufficient. Studies have found that high-entropy doping at the B site can improve the catalytic activity of the material towards fuel gas. This invention provides a method for... 3-δ By partially replacing Ti at the B site of perovskite materials with Co, Zr, Nb, and Ta, the electrochemical performance of SrTiO3-based anode materials was significantly improved, and solid oxide fuel cells prepared with this high-entropy material exhibited good ammonia catalytic performance.

[0032] The results of the examples show that, according to XRD characterization, the high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material provided by this invention, the product synthesized in air exhibits no impurity peaks and displays a stable cubic phase structure. The solid oxide fuel cell prepared using the high-entropy perovskite-type anode material provided by this invention has a maximum output power of 540 mW cm⁻¹ at 850°C in an H₂ atmosphere. -2 The maximum output power is 395 mW / cm² at 850°C in an NH₃ atmosphere. -2 This demonstrates that the material possesses excellent electrochemical performance and good ammonia catalytic performance. Attached Figure Description

[0033] Figure 1 SrTi, a high-entropy perovskite synthesized in air 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ XRD pattern.

[0034] Figure 2 To use the material SrTi of the present invention 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ Power density diagram of a full cell fabricated using the anode material in an H2 atmosphere.

[0035] Figure 3 To use the material SrTi of the present invention 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ Power density diagram of a full cell fabricated using an anode material in an NH3 atmosphere.

[0036] Figure 4 For the SrTi material of the present invention 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ Long-term stability of full cells fabricated using anode materials under NH3 atmosphere Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation steps, but the present invention is not limited to the following examples.

[0038] This invention provides a method for preparing a high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material, specifically including the following steps:

[0039] (1) Weigh out the raw materials SrCO3, TiO2, Co3O4, ZrO2, Nb2O5, and Ta2O5 in a molar ratio of 1:0.2:0.067:0.2:0.1:0.1;

[0040] (2) Place the weighed medicine obtained in step (1) into the ball mill jar in sequence, add agate balls at a ball-to-material ratio of 10:1, pour in an appropriate amount of alcohol and stir until uniform, then put it into the ball mill for ball milling for 24 hours.

[0041] (3) Take out the ball mill jar from step (2), use a dropper to extract the sample solution into the mortar, then dry the solution in the mortar and collect the powder.

[0042] (4) Collect the powder from step (3) into a crucible, place the crucible in a muffle furnace, and calcine at 1000°C for 10 hours in an air atmosphere;

[0043] (5) Place the powder calcined in step (4) into a mortar and grind it. After grinding, weigh 0.3g of powder and place it into a mold with a diameter of 13mm. Press it into a sheet under a pressure of 4MPa.

[0044] (6) Place the pressed sheet from step (5) into a high-temperature furnace and calcine it at 1200°C for 10 hours in an air atmosphere;

[0045] (7) Place the calcined sample piece from step (6) into a mortar and grind it into powder. Add an appropriate amount of anhydrous ethanol and grind it thoroughly. After grinding, dry the sample with a baking lamp to obtain SrTi. 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ Solid oxide fuel cell anode electrode powder;

[0046] This invention provides an application of a high-entropy perovskite-type direct ammonia solid oxide fuel cell anode material, characterized by the following steps:

[0047] (1) Weigh an appropriate amount of the SrTi obtained above. 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δSolid 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 1:1.5; the binder is prepared by mixing terpineol and ethyl cellulose in a mass ratio of 9:1) and ground evenly to form an anode electrode slurry.

[0048] (2) Weigh out an appropriate amount of SmBaCo2O 5+δ 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 solid-state method and sintered at 1150℃ for 10 hours.

[0049] (3) The electrode pastes obtained in steps (1) and (2) above are 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 Both sides of the cell are placed on an oven and dried for 8 minutes to obtain a full cell (the electrolyte sheet is sintered at 1400℃ for 10 hours using a dry pressing method to form a dense LSGM electrolyte sheet).

[0050] (4) The dried full-cell cells from step (3) are placed in a high-temperature tube furnace and calcined at 950°C for 2 hours under N2 atmosphere to obtain SrTi 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ Solid oxide fuel cells with the anode material as the anode material;

[0051] (5) After collecting the single cell obtained in step (4) with silver wire, seal one end of the ceramic tube with silver paste, with the cathode facing outwards, and fix it in a muffle furnace. The cathode and anode of the single cell are connected to the electrochemical workstation through the silver wire. Fuel gas (H2 and NH3) is introduced into the anode of the solid oxide fuel cell through the ceramic tube, and the cathode of the solid oxide fuel cell is placed in the outside air atmosphere. Direct current is generated and output to the outside through 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.

[0052] The SrTi prepared according to this invention was analyzed by X-ray diffraction. 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-δ Phase analysis of anode material powder, such as... Figure 1 This indicates that the material of the present invention has a simple structure and no obvious impurity peaks during the synthesis process.

[0053] For the material SrTi of the present invention 0.2 Co 0.2 Zr 0.2 Nb 0.2 Ta 0.2 O 3-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 2 , Figure 3 As shown, Figure 2 The maximum output power of the material of the present invention at 850°C in an H2 atmosphere is shown to be 540 mW / cm. -2 The maximum output power at 850℃ in an NH3 atmosphere is 395mW cm⁻¹. -2 This demonstrates that the material of this invention has excellent electrochemical performance and good ammonia catalytic performance.

[0054] 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 perovskite-type direct ammonia solid oxide fuel cell anode material, characterized in that, Its chemical formula is SrTi x Ta x Co x Zr x Nb x O3- δ Where x = 0.2, 0 ≤ δ ≤ 1, and δ is the oxygen vacancy content; the preparation method adopts the following steps: (1) According to the chemical formula SrTi x Ta x Co x Zr x Nb x O3- δ The stoichiometric ratio of the metal elements in the sample is determined by weighing samples containing Sr. 2+ carbonates containing Ti 4+ Oxides containing Co 3+ oxides containing Zr 4+ Oxides containing Nb 5+ oxides containing Ta 5+ Oxides; (2) Place the raw material weighed in step (1) into a ball mill jar, add agate balls and an appropriate amount of ethanol, and perform ball milling; (3) Take the slurry from step (2) out of the ball mill jar, dry it, and collect the powder; (4) Place the powder from step (3) into a muffle furnace for pre-firing; (5) Place the powder that was pre-burned in step (4) into a mortar and grind it. After grinding it thoroughly, weigh an appropriate amount of powder and put it into a mold to press it into a sheet. (6) Place the pressed sheet from step (5) into a high-temperature furnace for calcination; (7) Place the calcined sample sheet from step (6) into a mortar, add an appropriate amount of anhydrous ethanol for grinding, and dry the sample after thorough grinding to obtain high-entropy perovskite-type direct ammonia solid oxide fuel cell anode powder.

2. The preparation method according to claim 1, characterized in that, Step (1) contains Sr 2+ The carbonate is SrCO3, containing Ti 4+ The oxide is TiO2, containing Co 3+ The oxide is Co3O4, containing Zr 4+ The oxide is ZrO2, containing Nb 5+ The oxide is Nb₂O₅, containing Ta 5+ The oxide is Ta2O5; the SrTi x Ta x Co x Zr x Nb x O3- δ The molar ratio of Sr, Ti, Co, Zr, Nb, and Ta in the chemical formula is 1:0.2:0.2:0.2:0.2:0.

2.

3. The preparation method according to claim 1, characterized in that, In step (2), the ratio of agate balls added to the ball milling jar to the sample balls is (9-11):1, and the ball milling time is 20-30 h.

4. The preparation method according to claim 1, characterized in that, In step (4), the pre-firing temperature is 900-1100 ℃ and the pre-firing time is 8-12 h.

5. The preparation method according to claim 1, characterized in that, In step (5), the mass of the appropriate amount of powder is 0.3-1g, the diameter of the tableting mold is 10-15 mm, and the pressure of the tableting machine oil gauge is 2-5 MPa.

6. The preparation method according to claim 1, characterized in that, In step (6), the calcination temperature is 1100-1300 ℃ and the calcination time is 8-12 h.

7. The application of the high-entropy perovskite solid oxide fuel cell anode material prepared by any one of claims 1-6, characterized in that, The high-entropy perovskite solid oxide fuel cell anode material is used to prepare the anode in a solid oxide fuel cell.

8. The application according to claim 7, characterized in that, Solid oxide fuel cell single cells are prepared using the following steps: (1) Weigh an appropriate amount of the high-entropy perovskite SrTi obtained according to any one of claims 1-6. 0.2 Ta 0.2 Co 0.2 Zr 0.2 Nb 0.2 O3- δ The anode powder is placed in a mortar, and an appropriate amount of binder is added. The binder is composed of terpineol and ethyl cellulose in a mass ratio of 9:

1. The mixture is then ground to obtain a battery anode slurry, wherein the mass ratio of anode powder to binder is 1:(1.5-2.5). (2) Weigh a certain amount of SmBaCo2O 5+δ The cathode powder is placed in a mortar, and an appropriate amount of binder is added. The binder is composed of terpineol and ethyl cellulose in a mass ratio of 9:

1. The mixture is then ground to obtain a battery cathode slurry, wherein the mass ratio of cathode powder to binder is 1:(1.5-2.5). (3) The electrode pastes obtained in steps (1) and (2) above are 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; (4) Place the full cell obtained in step (3) in a high-temperature tube furnace and calcine it at 900-1100 °C for 2-4 h under N2 to obtain SrTi 0.2 Ta 0.2 Co 0.2 Zr 0.2 Nb 0.2 O3- δ Solid oxide fuel cells with anode material.

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