Preparation of a multi-doped layered perovskite anode and its application in ammonia solid oxide fuel cell

Abstract

The application belongs to the technical field of solid oxide fuel cell anode catalyst, and particularly relates to a preparation of a multi-doped layered perovskite anode and application thereof in ammonia solid oxide fuel cells. x Ba 1–x Mn 1–y TM y O 3–δ (0.4<=x<=0.6, 0<=y<=0.3, TM=Co, Fe, Cu), the precursor is phase changed under a reducing atmosphere to form a PrBaMn2O 5+δ layered perovskite with rich oxygen vacancies, and the doped transition metal is precipitated in the form of an alloy and anchored on the surface of the layered perovskite. The anode catalyst has a simple synthesis method, low cost, rich and flexible adjustable element composition. The obtained anode catalyst is made into a slurry and then assembled into a solid oxide fuel cell single cell sheet. The solid oxide fuel cell prepared by the application has good power output, electrical conductivity and stability at medium and high temperatures.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide fuel cell anode catalyst technology, specifically relating to the preparation of a multi-doped layered perovskite anode and its application in ammonia solid oxide fuel cells. Background Technology

[0002] Ammonia solid oxide fuel cells (SOFCs) are a highly efficient and clean energy conversion technology with broad application prospects in the context of "dual carbon" (carbon, oxygen, and carbon). However, traditional nickel-based anodes are prone to nitriding and microstructure degradation under ammonia fuel, leading to a decline in battery performance, which has become a key bottleneck for the application of ammonia SOFCs. Against this backdrop, precipitated perovskite materials, due to their unique interlocking structure, have advantages such as good metal dispersion, uniform size, and strong metal-carrier interaction, making them a promising candidate for anodes in ammonia SOFCs.

[0003] However, current perovskite anodes still face many bottlenecks. LaCrO3 exhibits excellent reduction stability and electronic conductivity, but its ionic conductivity is insufficient. This is often improved by introducing lower-coordination cations at the B-site, but this usually leads to a decrease in electronic conductivity (Solid State Ionics, 2007, 178(3-4): 307-312.). SrTiO3 has attracted widespread attention due to its excellent reduction stability, but it is almost a pure electronic conductor and usually needs to be combined with ionic conductors to improve performance (Chemical Engineering Journal, 2023, 471: 144650.). LaFeO3 possesses high mixed conductivity and good catalytic activity, but its structure is extremely unstable under reducing atmospheres (Fuel, 2025, 402: 136041.). Sr2FeMoO3... 6–δ It is currently the most widely studied perovskite anode, possessing high mixed conductivity, excellent catalytic activity, and good reduction stability. However, it is unstable in air and must be prepared under a reducing atmosphere, which requires stringent process conditions (Journal of Alloys and Compounds, 2024, 976: 173078.). Summary of the Invention

[0004] This invention addresses the shortcomings of current materials by providing a method for preparing a multi-doped layered perovskite anode and its application in ammonia solid oxide fuel cells. The anode catalyst in this invention exhibits good chemical and thermal compatibility with commonly used solid electrolytes and demonstrates good output performance at fuel cell operating temperatures, thus providing a material option for anode catalysts in solid oxide fuel cells.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A multi-doped layered perovskite anode, the precursor of which is composed of Pr x Ba 1–x Mn 1–y TM y O 3–δ Where 0.4≤x≤0.6, 0≤y≤0.3, TM=Co,Fe,Cu.

[0007] The perovskite-type Pr x Ba 1–x Mn 1–y TM y O 3–δ The oxide precursor and reduction process include the following steps:

[0008] 1) Weigh out 0.88–1.32 g Pr(NO3)3·6H2O, 0.52–0.78 g Ba(NO3)2, 0.62–0.88 g C4H6MnO4, 0–0.61 g Fe(NO3)3•9H2O, 0–0.44 g Co(NO3)2•6H2O, and 0–0.28 g Cu(NO3)2 according to the stoichiometric ratio. Dissolve the crystals in 50–100 mL of deionized water to obtain the corresponding metal salt aqueous solutions. Stir the solutions thoroughly with a magnetic stirrer for 60–120 min to obtain mixed solution A.

[0009] 2) Add a complexing agent solution to the mixed solution A obtained in 1) to obtain mixed solution B;

[0010] 3) Adjust the pH of mixed solution B using a buffer solution, and then carry out a water bath reaction until all the water in mixed solution B has evaporated to obtain a wet gel;

[0011] 4) The obtained wet gel was placed in an oven and dried at 120–180 °C for 12–24 h. After drying, it was ground into powder and then calcined by programmed temperature increase to obtain perovskite-type Pr. x Ba 1–x Mn 1–y TM y O 3–δ Oxide precursor.

[0012] 5) The perovskite oxide precursor is reduced by programmed temperature increase in a reducing atmosphere to obtain the anode catalyst.

[0013] The complexing agent solution mentioned in step 2) is a mixed solution of citric acid, EDTA and ethylene glycol, and the ratio of the total amount of metal ions, the amount of citric acid, EDTA and ethylene glycol in the mixed solution B is (1.0–1.5): (1.0–2.0): (0–1.0): (0–1.0).

[0014] The buffer solution mentioned in step 3) is one of ammonia buffer solution, triethylamine buffer solution or ethylenediamine buffer solution; the pH range mentioned in step 3) is 6–10.

[0015] Step 3) The water bath reaction specifically involves stirring the mixture in a water bath at 60–90 ℃ for 4–8 h.

[0016] The programmed heating temperature described in step 4) is 900–1100 ℃, and the heating time is 2–8 h.

[0017] The reducing atmosphere described in step 5) is 10% H2 / Ar, the programmed temperature for reduction is 600–800 °C, and the calcination time is 6–12 h.

[0018] The preparation of the multi-doped layered perovskite anode and its application in an ammonia solid oxide fuel cell includes the following steps:

[0019] (1) Add the terpineol solution containing ethyl cellulose to the prepared anode catalyst, mix thoroughly, and then obtain the anode slurry;

[0020] (2) The obtained anode paste is brushed onto the cathode La by screen printing. 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3–δ –(Ce 0.9 Gd 0.1 )O 1.95 (LSCF–GDC), with GDC as the separator and ScSZ as the electrolyte, an electrolyte-supported half-cell cell with the anode side is used to obtain a fuel cell cell. Then, the single cell is placed in a muffle furnace and sintered at 900–1100 °C for 1–8 h with a heating and cooling rate of 0.5–10 °C / min, finally obtaining a solid oxide fuel cell single cell cell.

[0021] The binder mentioned in step (1) is a mixture of ethyl cellulose and terpineol, wherein the content of ethyl cellulose is between 1 and 4 wt%.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. This invention discloses a novel composite anode material system with A-site ordered layered perovskite as the structural matrix, and B-site multi-metal (Co, Fe, Cu) synergistic doping, which allows for the controllable in-situ precipitation of multi-alloy nanoparticles, providing a completely new material design concept for ammonia solid oxide fuel cell anodes.

[0024] 2. Co / Fe co-doping produces a synergistic effect of optimizing matrix stability and promoting the formation of active sites; while the addition of Cu element, as a "reduction promoter", significantly reduces the precipitation temperature of the active alloy phase, realizing effective control of the size, distribution and number of alloy nanoparticles, thereby synergistically improving intrinsic activity and active site density.

[0025] 3. The in-situ precipitated alloy nanoparticles, through their moderate nitrogen binding energy, can optimize the ammonia decomposition pathway and promote N2 desorption, thereby effectively suppressing nitriding and significantly improving the long-term operational stability of the battery under ammonia fuel.

[0026] 4. The anode material system is not prone to reaction with conventional solid electrolytes, ensuring good interfacial compatibility and long-term thermochemical stability. Furthermore, its preparation process is compatible with existing battery manufacturing technologies, raw material costs are controllable, and its overall performance is excellent, possessing the potential for large-scale production and commercial application. Attached Figure Description

[0027] Figure 1 Pr is the embodiment of the present invention, 9th version. 0.5 Ba 0.5 Mn 0.8 Co 0.1 Fe 0.1 O 3–δ XRD patterns of the anode catalyst after calcination at 1100 °C for 5 hours (a) and reduction at 800 °C for 10 h under 10% H2 / Ar (b).

[0028] Figure 2 Pr is the embodiment of the present invention, 9th version. 0.5 Ba 0.5 Mn 0.8 Co 0.1 Fe 0.1 O 3–δ IVP plots of a single cell of the anode catalyst at 650–800 °C and 50 mL / min NH3. Detailed Implementation

[0029] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0030] Example 1

[0031] Pr 0.5 Ba 0.5 MnO 3–δ Preparation of anode slurry and its single cell:

[0032] (1) Weigh 1.10 g Pr(NO3)3·6H2O, 0.65 g Ba(NO3)2 and 0.88 g C4H6MnO4 according to the stoichiometric ratio. Dissolve the crystals in 50 mL of deionized water to obtain the corresponding nitrate aqueous solution. Stir the solution thoroughly for 60 min using a magnetic stirrer to obtain mixed solution A.

[0033] (2) Add a mixture of citric acid and EDTA to solution A obtained in (1) to obtain mixed solution B, wherein the ratio of the total amount of metal ions added to the amount of citric acid and EDTA is 1.0:1.1:0.5;

[0034] (3) Adjust the pH of solution B to 8 using ammonia buffer solution, and then place it in a water bath at 80 ℃ and stir for 6 h. Wait until the water in solution B evaporates completely to obtain wet gel.

[0035] (4) The obtained wet gel was placed in an oven and dried at 180 °C for 12 h. Then, it was heated to 1100 °C at a heating rate of 2 °C / min and calcined for 5 h to obtain the perovskite oxide precursor Pr. 0.5 Ba 0.5 MnO 3–δ ;

[0036] (5) The perovskite oxide precursor Pr was obtained 0.5 Ba 0.5 MnO 3–δ The anode catalyst was obtained by heating to 800 °C at a heating rate of 2 °C / min and reducing it in 10% H2 / Ar for 10 h.

[0037] (6) Add a terpineol solution containing 4 wt% ethyl cellulose and terpineol to the anode powder obtained in (5), mix evenly, and obtain anode slurry;

[0038] (7) The anode paste is brushed onto the cathode (La) by screen printing. 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3–δ –(Ce 0.9 Gd 0.1 )O 1.95(LSCF–GDC), with GDC as the separator and ScSZ as the electrolyte, an electrolyte-supported half-cell cell with the anode side is used to obtain a fuel cell cell. Then, the single cell is placed in a muffle furnace and sintered at 1100 °C for 2 h with a heating and cooling rate of 2 °C / min. Finally, a solid oxide fuel cell single cell cell is obtained.

[0039] Example 2

[0040] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.95 Co 0.05 O 3–δ .

[0041] Example 3

[0042] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.9 Co 0.1 O 3–δ .

[0043] Example 4

[0044] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.85 Co 0.15 O 3–δ .

[0045] Example 5

[0046] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.8 Co 0.2 O 3–δ .

[0047] Example 6

[0048] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.75 Co 0.25 O 3–δ .

[0049] Example 7

[0050] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.7 Co 0.3 O 3–δ .

[0051] Example 8

[0052] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.8 Co 0.15 Fe 0.05 O 3–δ .

[0053] Example 9

[0054] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.8 Co 0.1 Fe 0.1 O 3–δ . Figure 1 Pr is given 0.5 Ba 0.5 Mn 0.8 Co 0.1 Fe 0.1 O 3–δ XRD patterns of the reduction products were analyzed, revealing a simple perovskite structure consisting of a mixture of cubic and hexagonal phases, without the formation of secondary phases. After reduction, the structure shifted to an orthorhombic layered perovskite structure, and diffraction peaks were observed at ~44.87° for CoFe alloy (ICDD No. 00–049–1567), as well as for Pr₂O₃ (ICDD No. 01–082–1401), BaO (ICDD No. 00–001–0746), and Mn₂O₃ (ICDD No. 00–033–0900). Therefore, Pr₂O₃… 0.5 Ba 0.5 Mn 0.8 Co 0.1 Fe 0.1 O 3–δ In-situ precipitation of CoFe alloy was achieved through reduction, accompanied by partial decomposition of the matrix to maintain structural stability. Figure 2 The image shows the IVP (Inductively Coupled Power Count) of a battery using this material as the anode at 650–800 °C. The results show that its peak power density reaches 498 mW·cm⁻¹ at 800 °C. -2 .

[0055] Example 10

[0056] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.8 Co 0.05 Fe 0.15 O 3–δ .

[0057] Example 11

[0058] The specific preparation method in this embodiment is basically the same as that in Example 1, except that the precursor composition is Pr. 0.5 Ba 0.5 Mn 0.8 Fe 0.2 O 3–δ .

[0059] Product performance testing:

[0060] The single cell was fabricated using electrolyte-supported ScSZ (Shanghai Hydrogen Technology Co., Ltd., 15 mm in diameter). The cathode layer was LSCF–GDC (LSCF powder to GDC mass ratio of 2:3), with a diameter of 5 mm, and the separator was GDC, with a diameter of 10 mm. The anode layer was r–PBMC. x F y The diameter is 10 mm. The electrode is coated using screen printing technology.

[0061] The single-cell assembly process is as follows: First, a 5×5 mm square of silver paste is applied to the cathode side as a current collector. Second, a platinum wire and a nickel mesh are placed on the reactor inlet, with the anode side of the single cell facing the fuel gas. Third, a silver mesh (the same size as the silver paste) is placed on the cathode side, and then the platinum wire is placed on top, ensuring a tight connection. Finally, the reactor joints are sealed with ceramic adhesive to ensure the device's airtightness. Platinum paste is applied between the platinum wire and the current collector to ensure a tight connection. The fuel cell performance was measured using the dual-electrode method, with silver wires connecting the positive and negative electrodes of the electrochemical workstation (Zahner IM6). Under laboratory conditions, 50 mL / min of NH3 was introduced, and the output power density, current density, and polarization impedance of the obtained fuel cell at 800 °C were tested using an IM6 electrochemical analyzer. The results are shown in Table 1.

[0062] Table 1 Peak power density of direct ammonia solid oxide fuel cells at 800 °C

[0063] Example anode <![CDATA[Peak power density (mW·cm -2 )]]> Example 1 <![CDATA[Pr 0.5 Ba 0.5 MnO 3–δ ]]> 271 Example 2 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.95 Co 0.05 O 3–δ ]]> 305 Example 3 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.9 Co 0.1 O 3–δ ]]> 349 Example 4 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.85 Co 0.15 O 3–δ ]]> 386 Example 5 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.8 Co 0.2 O 3–δ ]]> 421 Example 6 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.75 Co 0.25 O 3–δ ]]> 392 Example 7 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.7 Co 0.3 O 3–δ ]]> 354 Example 8 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.8 Co 0.15 Feb 0.05 O 3–δ ]]> 463 Example 9 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.8 Co 0.1 Feb 0.1 O 3–δ ]]> 498 Example 10 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.8 Co 0.05 Feb 0.15 O 3–δ ]]> 447 Example 11 <![CDATA[Pr 0.5 Ba 0.5 Mr 0.8 Feb 0.2 O 3–δ ]]> 383

[0064] As can be seen from Table 1, the anode exhibits the best performance when the doping amount is y = 0.20. Furthermore, the anode exhibits the best performance when the doping ratio of Co to Fe is 1:1.

[0065] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A multi-doped layered perovskite anode, characterized in that: Under a reducing atmosphere, perovskite-type Pr x Ba 1–x Mn 1– y TM y O 3–δ In-situ precipitation of oxide precursors into alloys, anchored to PrBaMn2O with abundant oxygen vacancies. 5+δ Catalyst surface; where 0.4≤x≤0.6, 0≤y≤0.3, TM=Co,Fe,Cu.

2. The method for preparing a multi-doped layered perovskite anode as described in claim 1, characterized in that, Includes the following steps: 1) Take Pr(NO3)3·6H2O, Ba(NO3)2, C4H6MnO4, Fe(NO3)3•9H2O, Co(NO3)2•6H2O, and Cu(NO3)2. Dissolve the above crystals completely in 50-100 mL of deionized water to obtain the corresponding metal salt aqueous solution. Stir the solution thoroughly with a magnetic stirrer for 60-120 min to obtain mixed solution A. 2) Add a complexing agent solution to the mixed solution A obtained in 1) to obtain mixed solution B; 3) Adjust the pH of mixed solution B using a buffer solution, and then carry out a water bath reaction until all the water in mixed solution B has evaporated to obtain a wet gel; 4) The obtained wet gel was placed in an oven and dried at 120-180 °C for 12-24 h. After drying, it was ground into powder and then calcined by programmed temperature increase to obtain perovskite-type Pr. x Ba 1–x Mn 1–y TM y O 3–δ Oxide precursors; 5) The perovskite oxide precursor is reduced by programmed temperature increase in a reducing atmosphere to obtain the anode catalyst.

3. The preparation method according to claim 2, characterized in that, The mass ratio of Pr(NO3)3·6H2O, Ba(NO3)2, C4H6MnO4, Fe(NO3)3•9H2O, Co(NO3)2•6H2O, and Cu(NO3)2 in step 1) is (0.88-1.32):(0.52-0.78):(0.62-0.88):(0-0.61):(0-0.44):(0-0.28).

4. The preparation method according to claim 2, characterized in that, The complexing agent solution mentioned in step 2) is a mixed solution of citric acid, EDTA and ethylene glycol, and the ratio of the total amount of metal ions, the amount of citric acid, EDTA and ethylene glycol in the mixed solution B is (1.0-1.5):(1.0-2.0):(0-1.0):(0-1.0).

5. The preparation method according to claim 2, characterized in that: The buffer solution mentioned in step 3) is any one of ammonia buffer solution, triethylamine buffer solution or ethylenediamine buffer solution; the pH value is adjusted to a range of 6–10; the water bath reaction is specifically carried out by stirring in a water bath at 60–90 ℃ for 4–8 h.

6. The preparation method according to claim 2, characterized in that: The temperature for the programmed heating and roasting described in step 4) is 900–1100 °C, and the roasting time is 2–8 h.

7. The preparation method according to claim 2, characterized in that: The reducing atmosphere described in step 5) is 10% H2 / Ar, the programmed temperature for reduction is 600-800 ℃, and the calcination time is 6-12 h.

8. The application of the multi-doped layered perovskite anode as described in claim 1 in the preparation of ammonia solid oxide fuel cells, characterized in that: Includes the following steps: (1) Add the binder to the prepared perovskite-type anode catalyst, mix thoroughly, and then obtain the anode slurry; (2) The obtained anode paste is brushed onto the cathode La by screen printing. 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3–δ –(Ce 0.9 Gd 0.1 )O 1.95 A half-cell electrolyte support with GDC as the separator and ScSZ as the electrolyte is used to support the anode side of the cell to obtain a fuel cell sheet. Then, the single cell is placed in a muffle furnace and sintered at 900-1100 °C for 1-8 h with a heating and cooling rate of 0.5-10 °C / min to finally obtain a solid oxide fuel cell single cell sheet.

9. The application according to claim 8, characterized in that: The binder mentioned in step (1) is a mixture of ethyl cellulose and terpineol, wherein the content of ethyl cellulose is between 1-4 wt%.

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