Solid oxide fuel cell preparation and performance prediction method based on direct ammoxidation anode

Abstract

The invention relates to a preparation and performance prediction method of a solid oxide fuel cell based on a direct ammoxidation anode, the anode material is scheelite structure chromate oxide, the chemical formula of the anode material is SrCr1-xNixO4 + delta, 0 < = x < = 0.4, 0 < delta < 1, nanoscale metal Ni particles are precipitated in situ under the condition of B-site Ni doping induction high-temperature reduction, and the solid oxide fuel cell is obtained. Ni particles are uniformly distributed and are not agglomerated; a sol-gel method is combined with a gradient roasting process to synthesize the anode material, so that Ni doping is controlled, and in-situ controllable precipitation of Ni particles is realized; and establishing an ammonia decomposition-charge transfer coupling element reaction kinetic equation based on the mixed conductivity characteristic of the anode material and the Ni particle distribution rule, and quantitatively predicting the battery performance under different Ni doping amounts. According to the method, the electrochemical performance of the direct ammonia solid oxide fuel cell at a high temperature is improved, and pre-screening of the anode material and performance prediction of experimental conditions which are difficult to achieve by people before an experiment are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode. Background Art

[0002] As a new clean energy conversion technology, direct ammonia solid oxide fuel cells (DA-SOFCs) have significant advantages in the following aspects: First, they can directly use ammonia as fuel, achieving zero carbon emissions, which is of great significance for reducing greenhouse gas emissions and mitigating global climate change; second, ammonia has a high energy density and has a higher energy utilization rate than traditional fossil fuels; third, ammonia is safe to store and transport and is not prone to explosion, reducing safety risks during energy transportation and storage. However, existing DA-SOFC technology still faces several technical bottlenecks that restrict its further development and application. First, the ammonia decomposition activity of traditional anode materials such as Ni-YSZ is insufficient, resulting in low ammonia oxidation efficiency at the anode, affecting the overall battery performance; second, carbon deposition and sintering are common problems in DA-SOFCs, which can lead to the degradation of battery performance and reduce its long-term stability; in addition, there is currently a lack of multi-scale reaction mechanism models to guide material design, which makes material selection and optimization lack a scientific basis.

[0003] Chinese patent CN113991135A discloses a solid oxide fuel cell and its preparation method, which uses traditional NiO as the anode material and designs it into the style of an anode support. However, this method has a complicated process flow and has not yet broken through the limitations of traditional anode materials.

[0004] Chinese patent CN116190688A discloses a strontium titanate-based anode catalyst for direct ammonia solid oxide fuel cells and its preparation method. The direct ammonia solid oxide fuel cell anode catalyst is a single perovskite structure Sr sintered at high temperature. x Ti 1–y Ni y O 3+δ Oxides. This type of material uses A-site defects and B-site doping to achieve high ammonia utilization and good stability of the solid oxide direct ammonia fuel cell anode for ammonia fuel gas. However, it has the disadvantage of a complex process flow and requires complex material modification to achieve high performance.

[0005] Chinese patent CN118298942A provides a method for establishing a model of a direct ammonia fuel cell based on an ammonia decomposition catalytic layer. By decoupling the ammonia decomposition reaction and charge transfer reaction between the catalytic layer and the anode, the battery performance under different ammonia decomposition conditions can be predicted. However, the model is only applicable to direct ammonia solid oxide fuel cells that include an anode catalytic layer and has a narrow scope of application. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode, so as to improve the electrochemical performance of the direct ammonia solid oxide fuel cell at high temperature, and to achieve pre-screening of anode materials before the experiment and performance prediction under experimental conditions that are difficult to achieve artificially.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode, wherein the anode material is a chromate-based oxide of a scheelite structure, and its chemical formula is SrCr 1-x Ni x O 4+δ , where 0≤x≤0.4, 0<δ<1, nano-sized metallic Ni particles are precipitated in situ under high-temperature reduction conditions by B-site Ni doping, and the Ni particles are evenly distributed without agglomeration;

[0008] The anode material is synthesized by a sol-gel method combined with a gradient calcination process to control Ni doping and achieve in-situ controllable precipitation of Ni particles;

[0009] Based on the mixed conductive properties of the anode material and the distribution law of Ni particles, a kinetic equation for the ammonia decomposition-charge transfer coupling elementary reaction is established to quantitatively predict the battery performance under different Ni doping amounts.

[0010] Furthermore, the method comprises the following steps:

[0011] (1) Synthesis of SrCr by sol-gel method combined with gradient calcination process 1-x Ni x O 4+δ Oxide: Sr(NO3)2, Cr(NO3)3·9H2O, and nickel salt are weighed according to the stoichiometric ratio and dissolved in deionized water to obtain solution A; solution B is prepared with a molar ratio of metal ions to complexing agent of 1.5-2:1; solutions A and B are mixed and stirred for a set time, then incubated in a water bath at 85-100°C for a set time to form a gel, dried at 150-180°C for a set time, and then ground and gradient calcined to obtain the product;

[0012] (2) Prepare a thickener solution containing 4-10 wt% thickener: mix the dispersant and the binder in a mass ratio of (4-10): (96-90), bath in a 40-80°C water bath until transparent, and refrigerate for later use; 1-x Ni x O 4+δ The oxide and YSZ were mixed in a mass ratio of 40:60, a thickener solution was added, and the mixture was ball-milled for a set time to prepare the SCNOx-YSZ anode slurry;

[0013] (3) Using YSZ as the electrolyte, a direct ammonia solid oxide fuel cell was prepared by screen printing: Mg was first printed on one side of the electrolyte. 0.4 Ni 1.4 Mn 1.2 O 4+δ -60YSZ cathode slurry, dried at 80-100℃ for a set time and then calcined; then print SCNOx-YSZ anode slurry on the other side of the electrolyte, dried at 80-100℃ for a set time and then calcined;

[0014] (4) Build a direct ammonia solid oxide fuel cell performance prediction model; based on the model assumptions, simplify the battery into a one-dimensional elementary reaction model, including an anode, an electrolyte, and a cathode, with the anode being a mixed ion-electron conductor; use the anode's ammonia decomposition reaction and charge transfer reaction as the anode's reaction equations, and through charge transfer reaction kinetic calibration and ammonia decomposition reaction kinetic calibration, make the model's hydrogen oxidation process and ammonia decomposition process match the actual situation; then quantitatively predict the battery performance under different Ni doping amounts through the established direct ammonia solid oxide fuel cell performance prediction model.

[0015] Furthermore, in step (1), the nickel salt is a combination of one or more of nickel chloride hexahydrate, nickel nitrate hexahydrate, nickel acetate, and nickel sulfate.

[0016] Furthermore, in step (1), the complexing agent is a combination of one or more of citric acid, oxalic acid, and salicylic acid.

[0017] Furthermore, in step (1), the gradient calcination process is: pre-calcination at 600-800°C for 4 hours, maintaining the heating rate at 5-10°C / min, and then calcination at 1000°C in air atmosphere for 2-4 hours, maintaining the heating rate at 2-5°C / min.

[0018] Furthermore, in step (2), the dispersant is a combination of one or more of terpineol, neroli oil, orange leaf oil, camphor oil, and lemon oil.

[0019] Furthermore, in step (2), the binder is one of ethyl cellulose, hydroxyethyl cellulose, methyl cellulose, guar gum, and polyacrylamide.

[0020] Furthermore, in step (3), the cathode side calcination process of the direct ammonia solid oxide fuel cell is: calcination at 1100°C for 2-5 hours, and the heating rate is maintained at 2-4°C / min; the anode side calcination process is: calcination at 1000°C for 2-5 hours, and the heating rate is maintained at 2-4°C / min.

[0021] Furthermore, in step (4), the model assumes that: the gases involved in the reaction are assumed to be ideal gases; the mixed ion-electron conductor constituting the anode and the ion conductor constituting the cathode are uniformly distributed and continuous; and the effects of gas phase reaction, gas flow and heat transfer are ignored.

[0022] Furthermore, in step (4), the elementary reactions include ammonia adsorption and desorption, ammonia stepwise dehydrogenation, hydrogen adsorption and desorption, nitrogen adsorption and desorption, and charge transfer reaction.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention provides a scheelite structure chromate-based oxide SrCr 1-x Ni x O 4+δ As the anode material of solid oxide fuel cells, the introduction of ammonia during the application process of the fuel cell can realize the in-situ precipitation of Ni nanoparticles, improve the anti-sintering properties of the Ni precipitated particles on the sample surface, promote their uniform distribution, and help NH3 obtain more reaction active sites on the anode surface, greatly promoting the catalytic activity of the anode material at medium and low temperatures.

[0025] (2) The research process shows that the ammonia conversion efficiency can be significantly improved by regulating the doping ratio of the Ni element. When the Ni doping amount reaches the optimal value, the battery power output performance of ammonia fuel is comparable to that of hydrogen fuel. This discovery provides a theoretical basis and technical support for ammonia as a new clean energy carrier.

[0026] (3) The present invention provides a performance prediction method for solid oxide fuel cells based on SrCr 1- x Ni x O 4+δ The direct ammonia solid oxide fuel cell with an oxide anode is the research object. Through model calculation, the electrochemical performance under different operating conditions and different anode material structures is predicted, and the paths of different ammonia oxidation reactions inside the anode are quantitatively analyzed. This can realize the pre-screening of anode materials before the experiment and the performance prediction under experimental conditions that are difficult to achieve artificially. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 SrCr prepared in Example 1 of the present invention0.8 Ni 0.2 O 4+δ XRD spectra of anode material samples after reduction under different reduction conditions;

[0028] Figure 2 SrCr prepared in Examples 1-5 of the present invention 1-x Ni x O 4+δ SEM images of a series of anode material samples;

[0029] Figure 3 Schematic diagram and model establishment diagram of the solid oxide fuel cell according to Example 6 of the present invention;

[0030] Figure 4 Calibration charts established for the models of Examples 6-8 of the present invention;

[0031] Figure 5 This is a graph predicting the electrochemical performance of Examples 9-12 of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0034] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0035] This embodiment provides a method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode. The anode material is a chromate-based oxide with a scheelite structure and a chemical formula of SrCr 1-x Ni x O 4+δ (0≤x≤0.4, 0<δ<1), by inducing the in-situ precipitation of nano-sized metal Ni particles under high-temperature reduction conditions through B-site Ni doping, and the Ni particles are more evenly distributed and non-agglomerated, thereby promoting the increase of reactive sites on the sample surface, thereby improving the electrochemical performance of the corresponding battery as the anode.

[0036] The anode material is synthesized by a sol-gel method combined with a gradient calcination process to control Ni doping and achieve in-situ controllable precipitation of Ni particles.

[0037] Based on the mixed conductive properties of the anode material and the distribution law of Ni particles, a kinetic equation for the ammonia decomposition-charge transfer coupling elementary reaction is established to quantitatively predict the battery performance under different Ni doping amounts.

[0038] The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode specifically comprises the following steps:

[0039] (1) Scheelite-type SrCr 1-x Ni x O 4+δ Synthesis of oxides

[0040] SrCr was synthesized by sol-gel method combined with gradient calcination process. 1-x Ni x O 4+δ Oxide: According to the stoichiometric ratio, weigh 21.16-42.33 g of Sr(NO3)2, 32.01-64.02 g of Cr(NO3)3·9H2O and 5.82-11.63 g of nickel salt, dissolve them in 200-400 ml of deionized water, and stir with a magnetic stirrer for 2 hours to obtain solution A.

[0041] Prepare solution B with a molar ratio of metal ions to complexing agent of 1.5-2:1: according to the molar ratio of total metal ions to complexing agent in solution A of 1.5-2:1, weigh the corresponding weight of complexing agent, add 200-400 ml of deionized water to dissolve it, and stir and dissolve it with a magnetic stirrer for 2-4 hours to obtain solution B.

[0042] After the solution is prepared, the speed of the magnetic stirrer is adjusted to 300-600r / min, and the A and B solutions are quickly mixed. After stirring for 12-20 hours, stirring is stopped, and a water bath is placed at a temperature of 85-100°C for 4-6 hours. After a large amount of solvent evaporates and a transparent gel is formed, heating and stirring are stopped, and the solution is placed in a high-temperature blast drying oven at a temperature of 150-180°C. After drying for 12-24 hours, the solution is cooled, ground, and roasted to obtain scheelite SrCr 1-x Ni x O 4+δ oxide.

[0043] In step (1), the nickel salt is a combination of one or more of nickel chloride hexahydrate, nickel nitrate hexahydrate, nickel acetate, and nickel sulfate. The complexing agent is a combination of one or more of citric acid, oxalic acid, and salicylic acid.

[0044] The gradient calcination process is: pre-calcination at 600-800°C for 4 hours, maintaining a heating rate of 5-10°C / min, and then calcination at 1000°C in air atmosphere for 2-4 hours, maintaining a heating rate of 2-5°C / min.

[0045] (2) Scheelite-type SrCr 1-x Ni x O 4+δ Oxide preparation of anode slurry

[0046] Prepare a thickener solution containing 4%-10% thickener by mass. The basic preparation process is as follows: First, mix the dispersant (thickener) and binder in a mass ratio of (4-10): (96-90). Heat in a water bath at a temperature of 40-80°C. Once the thickener becomes clear and transparent, remove from the water bath, cool, and refrigerate at 0-5°C.

[0047] SrCr 1-x Ni x O 4+δ Oxide pretreatment to prepare anode slurry: SrCr 1-x Ni x O 4+δ The oxide sample and YSZ are mixed in a mass ratio of 40:60, 3-10 drops of the viscosity agent solution are slowly added, and the mixture is ball-milled for 10-12 hours to obtain a SCNOx-YSZ composite slurry.

[0048] In step (2), the dispersant is a combination of one or more of terpineol, neroli oil, orange leaf oil, camphor oil, and lemon oil. The binder is one of ethyl cellulose, hydroxyethyl cellulose, methyl cellulose, guar gum, and polyacrylamide.

[0049] (3) Scheelite-type SrCr 1-x Ni x O 4+δ Direct ammonia solid oxide fuel cells using oxide anodes

[0050] The YSZ with a diameter of 15 mm was used as the electrolyte, and Mg 0.4 Ni 1.4 Mn 1.2 O 4+δ A direct ammonia solid oxide fuel cell (DSOC) was prepared using a screen printing method using a composite slurry of YSZ-60YSZ (J. Power. Sources 2021, 503: 230020) as the cathode material and a composite slurry of SCNOx-YSZ as the anode material. The specific preparation process is as follows:

[0051] The cathode slurry was coated on one side of the electrolyte sheet (5 mm in diameter and 0.196 cm in active area) by screen printing. 2 ), put it into an oven and keep it at 80-100℃ for 20-60min before calcining. After cooling naturally, the same method as above was used to make a 10mm diameter and 0.785cm effective area on the other side of the electrolyte sheet. 2 ) Print the anode slurry, dry it and then calcine it.

[0052] In step (3), the cathode side calcination process of the direct ammonia solid oxide fuel cell is: calcination at 1100°C for 2-5 hours, and the heating rate is maintained at 2-4°C / min; the anode side calcination process is: calcination at 1000°C for 2-5 hours, and the heating rate is maintained at 2-4°C / min.

[0053] (4) For scheelite-type SrCr 1-x Ni x O 4+δ Build a performance prediction model for direct ammonia solid oxide fuel cells with oxide as anode;

[0054] Targeting SrCr 1-x Ni x O 4+δ A rational simplification of a direct ammonia solid oxide fuel cell (DSOCF) with an oxide anode was performed. Based on the model's assumptions, the cell was simplified into a one-dimensional elementary reaction model, consisting of an anode, electrolyte, and cathode, with the anode being a mixed ion-electron conductor. The one-element elementary reaction model was used to describe the anode's ammonia decomposition and charge transfer reactions. These reactions were used as the anode's reaction equations. Through charge transfer reaction kinetic calibration and ammonia decomposition reaction kinetic calibration, the model's hydrogen oxidation and ammonia decomposition processes were aligned with actual conditions. The established DSOCF performance prediction model was then used to quantitatively predict the cell performance at different Ni doping levels.

[0055] In step (4), the model assumes that the gases involved in the reaction are assumed to be ideal gases; the mixed ion-electron conductor (anode) and the ion conductor (cathode) in the electrode are uniformly and continuously distributed; and the effects of gas phase reaction, gas flow and heat transfer are ignored.

[0056] The elementary reactions include ammonia adsorption and desorption, ammonia stepwise dehydrogenation, hydrogen adsorption and desorption, nitrogen adsorption and desorption, and charge transfer reaction.

[0057] The specific implementation process of the present invention is further described below through specific embodiments.

[0058] 1. Based on scheelite SrCr 0.8 Ni 0.2 O 4+δPreparation of anode for direct ammonia solid oxide fuel cells

[0059] Example 1

[0060] (1) Weigh 21.16 g of Sr(NO3)2, 32.01 g of Cr(NO3)3·9H2O, and 5.82 g of Ni(NO3)2·6H2O into a 500 ml beaker, pour into 300 ml of deionized water to dissolve, and stir thoroughly for 2 hours to obtain metal salt solution A. According to the molar ratio of total metal ions: complexing agent in solution A of 1.5:1, weigh 25.62 g of citric acid, add 300 ml of deionized water to dissolve, stir and dissolve for 2 hours, and record it as clear and transparent solution B. After the solution is prepared, adjust the speed of the magnetic stirrer to 300 r / min, quickly pour solution B into solution A, continue stirring for 12 hours, stop stirring, place in a water bath, set the temperature to 85℃ and maintain for 5 hours, wait until the solvent evaporates in large quantities and a transparent gel is formed, then stop heating and stirring, place the beaker in a high-temperature forced air drying oven, dry at 150℃ for 12 hours, remove and cool, and obtain a loose porous material. The bulk loose porous material in the beaker was taken out with a medicine spoon and placed in an agate mortar to be fully ground into powder. The powder was placed in a dish using a gradient roasting process and pre-roasted at 600 ° C for 4 hours to obtain the sample precursor powder; the precursor powder was roasted at 1000 ° C in an air atmosphere for 2 hours to obtain scheelite SrCr 0.8 Ni 0.2 O 4+δ Oxide samples.

[0061] (2) In pre-treatment of SrCr 0.8 Ni 0.2 O 4+δ Before preparing the anode material, a 4wt% ethyl cellulose / terpineol solution must be prepared. The specific preparation method is: accurately weigh ethyl cellulose and terpineol (mass ratio 4:96) and place them in a beaker. Stir continuously in a 60°C water bath until the solution is completely clear and transparent. Then, stop heating, cool to room temperature, and transfer to a 0°C refrigerator for storage.

[0062] During the anode slurry preparation process, SrCr was first accurately weighed according to the mass ratio of 4:6. 0.8 Ni 0.2 O 4+δ Place it in an agate mortar with YSZ powder. Use mechanical grinding to mix thoroughly for 20 minutes until the two powders are evenly dispersed and there is no obvious particle agglomeration. Then use a 3mL dropper to add 5 drops of terpineol solution as a dispersion medium and continue grinding for 15 minutes to form a uniform viscous slurry. Finally, SrCr with good dispersion is obtained. 0.8 Ni 0.2 O4+δ -60YSZ composite anode slurry.

[0063] (3) Based on scheelite SrCr 1-x Ni x O 4+δ Preparation of direct ammonia solid oxide fuel cells with oxide anodes

[0064] Direct ammonia solid oxide fuel cell chip uses 15mm diameter YSZ as electrolyte, Mg 0.4 Ni 1.4 Mn 1.2 O 4+δ -60YSZ (J.Power.Sources 2021,503:230020) composite slurry is the cathode material, SrCr 1-x Ni x O 4+δ -60YSZ composite slurry was used as the anode material to prepare a single cell by screen printing. The specific preparation process is as follows: the cathode slurry was coated on one side of the electrolyte sheet (diameter 5mm, effective area 0.196cm) by screen printing. 2 ), put it into an oven and keep it at 80℃ for 20min before calcining. After cooling naturally, the same method as above was used to prepare the other side of the electrolyte sheet (diameter 10mm, effective area 0.785cm 2 ) Print the anode slurry, dry it and calcine it. After cooling, SrCr 0.8 Ni 0.2 O 4+δ -60YSZ|YSZ|Mg 0.4 Ni 1.4 Mn 1.2 O 4+δ -60YSZ single cell. Using a reduction process, 5% H2 / N2 is introduced during the battery startup phase, followed by in-situ reduction at 700-800°C for 2 hours to achieve directional precipitation of Ni nanoparticles.

[0065] Example 2

[0066] The specific preparation method is basically the same as that in Example 1, except that the scheelite SrCr 0.8 Ni 0.2 O 4+δ The synthesis of oxides was changed to scheelite SrCrO 4+δ In the synthesis of oxides, 32.01 g of Cr(NO3)3·9H2O was changed to 40.01 g of Cr(NO3)3·9H2O, and 5.82 g of Ni(NO3)2·6H2O was changed to 0 g of Ni(NO3)2·6H2O.

[0067] Example 3

[0068] The specific preparation method is basically the same as that in Example 1, except that the scheelite SrCr 0.8 Ni 0.2 O 4+δ The synthesis of oxides was changed to scheelite SrCr 0.9 Ni 0.1 O 4+δ In the synthesis of oxides, 32.01 g of Cr(NO3)3·9H2O was changed to 36.01 g of Cr(NO3)3·9H2O, and 5.82 g of Ni(NO3)2·6H2O was changed to 2.91 g of Ni(NO3)2·6H2O.

[0069] Example 4

[0070] The specific preparation method is basically the same as that in Example 1, except that the scheelite SrCr 0.8 Ni 0.2 O 4+δ The synthesis of oxides was changed to scheelite SrCr 0.7 Ni 0.3 O 4+δ In the synthesis of oxides, 32.01 g of Cr(NO3)3·9H2O was changed to 28.01 g of Cr(NO3)3·9H2O, and 5.82 g of Ni(NO3)2·6H2O was changed to 8.72 g of Ni(NO3)2·6H2O.

[0071] Example 5

[0072] The specific preparation method is basically the same as that in Example 1, except that the scheelite SrCr 0.8 Ni 0.2 O 4+δ The synthesis of oxides was changed to scheelite SrCr 0.6 Ni 0.4 O 4+δ In the synthesis of oxides, 32.01 g of Cr(NO3)3·9H2O was changed to 24.01 g of Cr(NO3)3·9H2O, and 5.82 g of Ni(NO3)2·6H2O was changed to 11.63 g of Ni(NO3)2·6H2O.

[0073] Comparative Example 1

[0074] To prepare the anode slurry, NiO and YSZ powders were accurately weighed in a 4:6 mass ratio and placed in an agate mortar. Mechanical grinding was then performed for 20 minutes to thoroughly mix the two powders until they were uniformly dispersed and free of significant particle agglomeration. Five drops of terpineol solution were then added dropwise using a 3 mL dropper as the dispersion medium, and grinding was continued for 15 minutes to form a uniform, viscous slurry. This resulted in a well-dispersed Ni-60YSZ composite anode slurry.

[0075] 2. SrCr 0.8 Ni 0.2 O 4+δ Establishment of a performance prediction model for direct ammonia solid oxide fuel cells with -60YSZ as anode

[0076] Example 6

[0077] This example constructs an electrochemical performance model for a 600°C operating environment. The model system consists of three functional regions: the anode, electrolyte, and cathode. Specifically, it includes the following key physical processes: gas mass transfer within the porous medium of the anode, electrochemical reactions at the anode three-phase interface, carrier transport (electrons and ions) within the battery, and redox reactions in the cathode region. The specific implementation steps for model construction are as follows:

[0078] (1) Geometric modeling and area division

[0079] A one-dimensional geometric model was established based on the COMSOL Multiphysics simulation platform, including three functional areas: anode, electrolyte, and cathode. The model boundaries include: anode surface, anode / electrolyte interface, electrolyte / cathode interface, and cathode outer surface.

[0080] (2) Boundary condition setting

[0081] Based on the principle of charge conservation, ion transport boundaries exist in the model. The anode surface and cathode outer surface are set as insulating boundaries, while the anode / electrolyte interface and electrolyte / cathode interface are set as continuous boundaries. Based on the principle of electron charge conservation, the anode surface is set as a zero potential reference, and an operating voltage is applied to the cathode outer surface.

[0082] (3) Mass transfer process modeling

[0083] In the Species Transport Module, a custom governing equation is used to describe the gas diffusion behavior in the anode region according to Fick’s law, simulating the transport process of components including NH3, H2, N2, and H2O.

[0084] (4) Establishment of surface reaction kinetics and electrochemical reaction model equations

[0085] In the chemical reaction module, microscopic kinetic equations for surface adsorption and catalytic reactions in the anode and cathode regions were established. The reaction rate constants were expressed as Arrhenius equations, and the kinetic parameters were derived from a specialized database. In the electrochemical module, a secondary current distribution model was employed to describe the charge transfer process at the anode three-phase interface via a two-step hydrogen spillover mechanism. The Ni particle density was correlated with the activation energy of the charge transfer reaction to correct the pre-exponential factor in the Arrhenius equation.

[0086] (5) Model initial parameter setting

[0087] The temperature is 600°C, the pressure is 101.325 kPa (standard atmospheric pressure), the anode gas is 100% NH3, the cathode gas is air, the gas diffusion coefficient is calculated by the software's built-in database, and the remaining physical properties are obtained through experimental tests and literature research.

[0088] (6) Model verification method

[0089] The simulation results were aligned with the experimental data by adjusting the following key parameters: the exchange current densities i0_an and i0_ca associated with the charge transfer reaction, and β associated with the ammonia decomposition reaction. When satisfactory agreement between the experimental and model results was achieved, the model validation for that temperature point was complete. It is important to ensure that the correlation between i0 and temperature at each temperature condition conforms to the Arrhenius equation. If the validation results do not conform to this mathematical relationship, the entire validation process must be repeated.

[0090] Example 7

[0091] The specific modeling method is similar to that of Example 6, but there are differences in the following key parameter settings: the model temperature is set to 700°C, and only the coefficients of i0_an, i0_ca and β are optimized and adjusted.

[0092] Example 8

[0093] The specific modeling method is similar to that of Example 6, but there are differences in the following key parameter settings: the model temperature is set to 800°C, and only the coefficients of i0_an, i0_ca and β are optimized and adjusted.

[0094] Example 9

[0095] The specific modeling method is similar to that of Example 6, but there are differences in the following key parameter settings: the model inlet component is changed to 75% NH3 + 25% (75H2 + 25N2).

[0096] Example 10

[0097] The specific modeling method is similar to that of Example 6, but there are differences in the following key parameter settings: the model inlet component is changed to 50% NH3 + 50% (75H2 + 25N2).

[0098] Example 11

[0099] The specific modeling method is similar to that of Example 6, but there are differences in the following key parameter settings: the model inlet component is changed to 25% NH3 + 25% (75H2 + 25N2).

[0100] Example 12

[0101] The specific modeling method is similar to that of Example 6, but there are differences in the following key parameter settings: the model inlet component is changed to 5% NH3 + 75% (75H2 + 25N2).

[0102] Figure 1 SrCr 0.8 Ni 0.2 O 4+δ The XRD spectra of the anode material samples after reduction under different reduction conditions show that the diffraction peaks of the oxide are basically consistent with the standard card JCPDS00-035-0743, indicating that the prepared SrCr 0.8 Ni 0.2 O 4+δ The oxide is a monoclinic scheelite structure. 0.8 Ni 0.2 O 4+δ The oxide was subjected to reduction treatment under various conditions, including 800°C in a 5% H2 / N2 atmosphere for 3 and 10 hours, and 700°C in a 5% H2 / N2 atmosphere for 10 hours. The experimental results showed that the SCNO0.2 sample's lattice structure was destroyed during the reduction process, and its phase composition changed significantly. X-ray diffraction analysis revealed the appearance of characteristic diffraction peaks characteristic of metallic Ni during the phase transition, confirming the precipitation of the metallic Ni phase.

[0103] Figure 2 SrCr 1-x Ni x O 4+δ SEM images of a series of anode material samples. As the doping concentration of Ni element at the B position gradually increases, a large number of Ni nanoparticles begin to precipitate on the sample surface. Compared with the SCNO0.1 sample, the nanoparticles formed on the surface of the SCNO0.2 sample have smaller particle size and more uniform distribution. This nanoparticle precipitation process significantly increases the specific surface area of ​​the material and provides more active sites, thereby significantly improving the electrochemical performance and stability of the material. However, when the doping amount exceeds 0.2, the particle size of the nanoparticles increases significantly, and Ni element agglomeration occurs; especially when x = 0.4, this agglomeration phenomenon is particularly significant.

[0104] Figure 3 This is a schematic diagram and model establishment diagram of a solid oxide fuel cell according to Example 6. As can be seen in the figure, the direct ammonia solid oxide fuel cell model includes an anode, an electrolyte, and a cathode.

[0105] Figure 4This is the calibration chart obtained after the model was established and calibrated according to experimental data at different temperatures. The comparative analysis based on numerical simulation results and experimental data shows that the calculation model has high accuracy, and its simulation results are in good agreement with the experimental data, which can be used for subsequent performance prediction and in-depth research on the anode reaction mechanism.

[0106] Figure 5 To use the model to predict the electrochemical performance under different anode inlet compositions, the operating conditions can be changed by adjusting the anode model parameters. This can be used to predict the performance of the battery under different operating conditions and screen the operating conditions before the experiment, thereby reducing the experimental workload.

[0107] In this embodiment, the model is based on the cross section of a button-type electrolyte-supported direct ammonia solid oxide fuel cell, and a one-dimensional geometric distribution ( Figure 3 ). The ammonia decomposition reaction and the charge transfer reaction are used as the model reaction equations, and the model is calibrated with experimental data to ensure the accuracy of the model, thereby realizing the one-dimensional elementary reaction model. Figure 5 As shown, by changing the model parameters (such as operating conditions such as inlet gas composition, anode material properties such as anode thickness, etc.), the model can obtain different performance accordingly, thereby completing the prediction of battery performance.

[0108] Table 1 shows the current density and power density of direct ammonia solid oxide fuel cell at 800℃

[0109]

[0110] As can be seen from Table 1, by comparing Examples 1-5 and Comparative Example 1, as the Ni doping amount gradually increases, the maximum power density (MPD) of the SCNOx series battery shows a significant growth trend. Specifically, when the doping amount x = 0.2, the MPD of the SCNiO0.2-60YSZ composite anode single cell reaches 432mW·cm -2 , which are 3.2 times that of a single SCO anode cell (x = 0) without Ni doping and 7 times that of a single NiO anode cell. This phenomenon fully confirms that the doping strategy of introducing Ni at the B site can significantly improve the electrochemical performance of the material. Compared with the traditional Ni / YSZ system, the SCNO0.2 material exhibits superior performance characteristics, which indicates that this material has broad application potential in the field of direct hydrocarbon solid oxide fuel cells (DA-SOFC).

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode, characterized in that: The anode material is scheelite structure chromate-based oxide, its chemical formula is SrCr 1-x Ni x O 4+δ , where 0≤x≤0.4, 0<δ<1, nano-sized metallic Ni particles are precipitated in situ under high-temperature reduction conditions by B-site Ni doping, and the Ni particles are evenly distributed without agglomeration; The anode material is synthesized by a sol-gel method combined with a gradient calcination process to control Ni doping and achieve in-situ controllable precipitation of Ni particles; A performance prediction model for direct ammonia solid oxide fuel cells was constructed, and the battery performance under different Ni doping amounts was quantitatively predicted by the model.

2. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 1, characterized in that: The following steps are involved: (1) Synthesis of SrCr by sol-gel method combined with gradient calcination process 1-x Ni x O 4+δ Oxide: Sr(NO3)2, Cr(NO3)3·9H2O, and nickel salt are weighed according to the stoichiometric ratio and dissolved in deionized water to obtain solution A; solution B is prepared with a molar ratio of metal ions to complexing agent of 1.5-2:1; solutions A and B are mixed and stirred for a set time, then incubated in a water bath at 85-100°C for a set time to form a gel, dried at 150-180°C for a set time, and then ground and gradient calcined to obtain the product; (2) Prepare a thickener solution containing 4-10 wt% thickener: mix the dispersant and the binder in a mass ratio of (4-10): (96-90), bath in a 40-80°C water bath until transparent, and refrigerate for later use; 1-x Ni x O 4+δ The oxide and YSZ were mixed in a mass ratio of 40:60, a thickener solution was added, and the mixture was ball-milled for a set time to prepare the SCNOx-YSZ anode slurry; (3) Using YSZ as the electrolyte, a direct ammonia solid oxide fuel cell was prepared by screen printing: Mg was first printed on one side of the electrolyte. 0.4 Ni 1.4 Mn 1.2 O 4+δ -60YSZ cathode slurry, dried at 80-100℃ for a set time and then calcined; then print SCNOx-YSZ anode slurry on the other side of the electrolyte, dried at 80-100℃ for a set time and then calcined; (4) Build a direct ammonia solid oxide fuel cell performance prediction model; based on the model assumptions, simplify the battery into a one-dimensional elementary reaction model, including an anode, an electrolyte, and a cathode, with the anode being a mixed ion-electron conductor; use the anode's ammonia decomposition reaction and charge transfer reaction as the anode's reaction equations, and through charge transfer reaction kinetic calibration and ammonia decomposition reaction kinetic calibration, make the model's hydrogen oxidation process and ammonia decomposition process match the actual situation; then quantitatively predict the battery performance under different Ni doping amounts through the established direct ammonia solid oxide fuel cell performance prediction model.

3. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 2, characterized in that: In step (1), the nickel salt is a combination of one or more of nickel chloride hexahydrate, nickel nitrate hexahydrate, nickel acetate, and nickel sulfate.

4. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 2, characterized in that: In step (1), the complexing agent is a combination of one or more of citric acid, oxalic acid, and salicylic acid.

5. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 2, characterized in that: In step (1), the gradient calcination process is: pre-calcination at 600-800°C for 4 hours, maintaining the heating rate at 5-10°C / min, and then calcining at 1000°C in air atmosphere for 2-4 hours, maintaining the heating rate at 2-5°C / min.

6. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 2, characterized in that: In step (2), the dispersant is a combination of one or more of terpineol, neroli oil, orange leaf oil, camphor oil, and lemon oil.

7. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 2, characterized in that: In step (2), the binder is one of ethyl cellulose, hydroxyethyl cellulose, methyl cellulose, guar gum, and polyacrylamide.

8. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 2, characterized in that: In step (3), the cathode side calcination process of the direct ammonia solid oxide fuel cell is: calcination at 1100°C for 2-5 hours, and the heating rate is maintained at 2-4°C / min; the anode side calcination process is: calcination at 1000°C for 2-5 hours, and the heating rate is maintained at 2-4°C / min.

9. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 2, characterized in that: In step (4), the model assumes that the gases involved in the reaction are assumed to be ideal gases; the mixed ion-electron conductor constituting the anode and the ion conductor constituting the cathode are uniformly distributed and continuous; and the effects of gas phase reaction, gas flow and heat transfer are ignored.

10. The method for preparing and predicting the performance of a solid oxide fuel cell based on a direct ammonia oxidation anode according to claim 2, characterized in that: In step (4), the elementary reactions include ammonia adsorption and desorption, ammonia stepwise dehydrogenation, hydrogen adsorption and desorption, nitrogen adsorption and desorption, and charge transfer reaction.

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