A proton-conductor ceramic direct ammonia fuel cell and a method for manufacturing the same

Abstract

This invention relates to a proton conductor ceramic direct ammonia fuel cell and its preparation method. The fuel cell includes an electrolyte layer and a cathode and an anode located on opposite sides of the electrolyte layer. The anode has a gradient anode structure composed of an anode functional layer, an anode support layer, and a high-entropy alloy anode catalyst layer. The cathode is made of BCFZY, the electrolyte layer is made of BZCYYb, and both the anode support layer and the anode functional layer are NiO-BZCYYb composite materials. The high-entropy alloy anode catalyst layer is a porous FeCoNiCu-based structure formed by dealloying a FeCoNiCuAl precursor alloy. This invention effectively solves the technical bottlenecks of easy nitriding deactivation of Ni-based anodes and low catalytic efficiency in ammonia decomposition and nitrogen reduction reactions in existing proton conductor ceramic direct ammonia fuel cells. The high-entropy alloy catalyst layer significantly inhibits the formation of metal nitrides through the synergistic effect of multiple components, while optimizing the surface electronic structure and catalytic site distribution, thus greatly improving the catalytic activity of non-noble metals.

Description

Technical Field

[0001] This invention relates to proton ceramic fuel cells, and more specifically to a proton conductor ceramic direct ammonia fuel cell and its preparation method. Background Technology

[0002] Direct ammonia fuel cells (DAFCs) are a novel energy conversion technology that uses ammonia (NH3) as fuel to directly and efficiently convert the chemical energy of ammonia into electrical energy through an electrochemical process. With its significant advantages of high energy efficiency and zero carbon emissions, DAFCs show broad application prospects in renewable energy storage and distributed power generation. Ammonia, as an ideal form of hydrogen energy storage and transportation, is widely available, has mature industrial production technology, and can be liquefied under normal temperature and pressure conditions, making it highly convenient for storage and transportation. Furthermore, ammonia has a high energy density, and its electrochemical decomposition products are only nitrogen and water, causing no secondary pollution to the environment. It possesses excellent environmental friendliness and is an important choice for replacing traditional fossil fuels and achieving clean energy utilization.

[0003] Proton-conducting ceramic fuel cells (PCFCs), employing proton-conducting electrolyte materials, can achieve highly efficient electrochemical reactions within a mid-temperature range of 400-700℃. They also possess excellent thermal stability and structural integration, making them a crucial platform for advancing direct ammonia fuel cell technology. Compared to traditional oxygen-conducting solid oxide fuel cells (SOFCs), PCFCs effectively avoid nitrogen oxide formation during the electrochemical reaction process and significantly improve fuel utilization efficiency, making their application potential in the direct ammonia fuel cell field even more prominent.

[0004] However, when PCFCs are practically applied to direct ammonia fuel cell systems, using ammonia as fuel for electrochemical reactions, several key technological bottlenecks remain, severely restricting their performance improvement and industrialization:

[0005] Firstly, the catalytic reaction of ammonia (NH3) decomposing into hydrogen (H2) and nitrogen (N2) is mainly completed at the anode interface of the battery. Ni-based catalysts widely used in the existing technology are very easy to combine with nitrogen to form metal nitrides (such as Ni3N) under an ammonia atmosphere, which leads to a significant decrease in catalyst activity and causes problems such as catalyst particle coarsening and anode structure deterioration, which in turn seriously affects the electrochemical reaction performance and long-term operational stability of the battery.

[0006] Secondly, traditional anode materials generally have low catalytic efficiency for ammonia decomposition and nitrogen reduction reaction (NRR), especially in non-precious metal catalyst systems. Existing materials cannot simultaneously meet the high catalytic activity required for electrochemical reactions and the long service life required for long-term battery operation, and cannot adapt to the actual application needs of direct ammonia fuel cells.

[0007] Third, PCFC is a multi-layer structure design. In the existing manufacturing process, various different materials and multiple heat treatment processes are required to construct each functional layer. It is difficult to accurately match the thermal expansion coefficients of the materials of each functional layer. Furthermore, key issues such as the compactness control of the battery structure and the regulation of the interfacial adhesion between layers cannot be solved in a coordinated manner, resulting in poor molding quality of the multi-layer battery structure. At the same time, this manufacturing method is complex and has low controllability, which limits the mass production and engineering scale-up of the battery. Summary of the Invention

[0008] To address the problems of insufficient catalytic activity, anode nitriding, poor operational stability, and complex preparation in existing PCFCs for direct ammonia applications, this invention aims to provide a proton conductor ceramic direct ammonia fuel cell and its preparation method.

[0009] The proton conductor ceramic direct ammonia fuel cell according to the present invention includes an electrolyte layer and a cathode and an anode located on opposite sides thereon. The anode is a gradient anode structure composed of an anode functional layer, an anode support layer and a high-entropy alloy anode catalyst layer. The cathode is made of BCFZY material, the electrolyte layer is made of BZCYYb material, the anode support layer and the anode functional layer are both NiO-BZCYYb composite materials, and the high-entropy alloy anode catalyst layer is a porous FeCoNiCu-based structure formed by dealloying FeCoNiCuAl precursor alloy.

[0010] In a preferred embodiment, the dealloying treatment selectively removes most of the Al component from the FeCoNiCuAl precursor alloy, forming a connected porous structure at the original Al sites. In a preferred embodiment, the molar ratios of Fe, Co, Ni, Cu, and Al in the FeCoNiCuAl precursor alloy are each independently 0.8~1.2:0.8~1.2:0.8~1.2:0.8~1.2:0.8~1.2.

[0011] In a preferred embodiment, BZCYYb is BaZr. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ The BCFZY is BaCo 0.4 Fe 0.4 Zr0.1 Y 0.1 O 3-δ δ is between 0.1 and 0.5.

[0012] In a preferred embodiment, the mass percentage of NiO powder in the anode support layer is 50-60 wt%, and the mass percentage of BZCYYb powder is 40-50 wt%; the mass percentage of NiO powder in the anode functional layer is 60-70 wt%, and the mass percentage of BZCYYb powder is 30-40 wt%.

[0013] The preparation method of the above-mentioned proton conductor ceramic direct ammonia fuel cell according to the present invention includes the following steps: S1, using BZCYYb powder to prepare anode support layer, anode functional layer and electrolyte layer respectively by tape casting process, and assembling them in sequence; S2, using high entropy alloy powder to form a high entropy alloy anode catalyst layer on the outer surface of the anode support layer by screen printing process, and obtaining an integrated green body after drying; S3, performing isostatic pressing on the integrated green body, followed by co-sintering; S4, using BCFZY powder to form a cathode on the electrolyte layer by wet spraying process, and performing sintering (e.g. 950℃) and full cell reduction activation (e.g. H2 atmosphere) treatment to obtain a complete fuel cell.

[0014] In a preferred embodiment, the parameters of the casting process in step S1 are as follows: the casting blade height of the anode support layer is 500~700μm, the casting blade height of the anode functional layer is 40~60μm, the casting blade height of the electrolyte layer is 25~35μm, the substrate heating temperature of each layer is 45~55℃, the hot air purging temperature of each layer is 50~60℃, and the casting film belt movement speed is 0.1~0.2cm / s.

[0015] In a preferred embodiment, the preparation process of the high-entropy alloy powder in step S2 is as follows: Fe, Co, Ni, Cu and Al metal powders are mixed and then ball-milled for 10-12 hours to obtain FeCoNiCuAl precursor high-entropy alloy powder; the FeCoNiCuAl precursor high-entropy alloy powder is placed in a strong alkaline solution for dealloying treatment to remove most of the Al component and form porous FeCoNiCu-based high-entropy alloy powder.

[0016] In a preferred embodiment, the screen printing paste in step S2 is prepared by mixing high-entropy alloy powder, ethyl cellulose and terpineol, wherein the mass ratio of high-entropy alloy powder to ethyl cellulose is 8~10:1 and the mass ratio of high-entropy alloy powder to terpineol is 0.8~1.0:1; during preparation, zirconia beads with a diameter of 3~5 mm and a mass ratio of 3:1 are added, and the mixture is stirred at a speed of 250~350 r / min for 2~4 h.

[0017] In a preferred embodiment, the parameters for the isostatic pressing process in step S3 are: temperature 50~90℃, pressure 50~90MPa, and holding time 5~15min.

[0018] In a preferred embodiment, the co-sintering in step S3 adopts a multi-stage heating strategy: when the temperature is below 300℃, the heating rate is 0.5~1.5℃ / min; when the temperature is in the range of 300~1200℃, the heating rate is 4~6℃ / min; when the temperature is above 1200℃, the heating rate is 0.5~1.5℃ / min, the final sintering temperature is 1400~1500℃, and the holding time is 4~6h.

[0019] This invention constructs a gradient anode structure consisting of a cathode-electrolyte layer-anode functional layer-anode support layer-high-entropy alloy anode catalyst layer. Using BCFZY as the cathode material, BZCYYb as the electrolyte material, and NiO-BZCYYb composite material as the anode functional and support layers, combined with a porous high-entropy alloy catalyst layer, it effectively solves the technical bottlenecks of easy nitriding deactivation of Ni-based anodes and low catalytic efficiency in ammonia decomposition and nitrogen reduction reactions in existing proton conductor ceramic direct ammonia fuel cells. The high-entropy alloy catalyst layer significantly inhibits the formation of metal nitrides through the synergistic effect of multiple components, while the porous structure formed through dealloying optimizes the process. The surface electronic structure and catalytic site distribution significantly enhance the catalytic activity of non-precious metals. Combined with an integrated fabrication process of casting-stacking-screen printing-isostatic pressing-co-sintering, it not only strengthens the interfacial bonding and structural density of each functional layer and improves the matching of thermal expansion coefficients, avoiding interlayer delamination and pore defects, but also achieves process controllability and repeatability, adapting to the needs of large-scale production. Ultimately, this enables the fuel cell to exhibit excellent output power density and long-term operational stability in the mid-temperature range when using ammonia or hydrogen as fuel, providing a high-performance and highly reliable technical solution for the practical application of distributed ammonia energy systems. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a proton conductor ceramic direct ammonia fuel cell according to the present invention.

[0021] Figure 2 This is a process flow diagram of the preparation method of the proton conductor ceramic direct ammonia fuel cell according to the present invention.

[0022] Figure 3 These are SEM images and elemental distribution diagrams of the FeCoNiCu high-entropy alloy after treatment with alkaline etching / dealloying.

[0023] Figure 4 This is a cross-sectional SEM image of a proton conductor ceramic direct ammonia fuel cell according to the present invention.

[0024] Figure 5The output performance curves of the proton conductor ceramic direct ammonia fuel cell according to the present invention are shown at different temperatures.

[0025] Figure 6 The graph shows the electrochemical impedance spectroscopy (EIS) test results of the proton conductor ceramic direct ammonia fuel cell according to the present invention at different temperatures.

[0026] Figure 7 The curves showing the 100-hour constant current stability test results of the proton conductor ceramic direct ammonia fuel cell according to the present invention under an NH3 atmosphere are compared.

[0027] Figure 8 These are physical comparison images of the proton conductor ceramic direct ammonia fuel cell button cell according to the present invention. Detailed Implementation

[0028] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0029] like Figure 1 and Figure 2 As shown, the proton conductor ceramic direct ammonia fuel cell according to the present invention has a multilayer gradient composite structure, comprising, from top to bottom, a cathode 1, an electrolyte layer 2, an active interface layer (also known as an anode-functional layer, AFL) 3, an anode-support layer (ASL) 4, and a high-entropy alloy anode-catalytic layer (HEA-ACL) 5. When NH3, as fuel, contacts the high-entropy alloy anode-catalytic layer 5, a thermocatalytic decomposition reaction occurs under the action of the highly active catalytic sites in this layer, generating H2 and N2. H2 diffuses to the Ni catalytic sites in the anode support layer 4, where an electrochemical oxidation dissociation reaction occurs to generate H2. + The white arrow in the diagram indicates H. + The protons migrate through the electrolyte layer from the anode to the cathode, eventually combining with O2 at the cathode interface to generate H2O, thus completing the proton transport process of the electrochemical reaction.

[0030] The method for preparing a proton conductor ceramic direct ammonia fuel cell according to the present invention first includes utilizing barium zirconium cerium yttrium Ytterbium (BZCYYb) powder material was used to prepare the electrolyte layer 2, the anode functional layer 3, and the anode support layer 4 through a casting process, and then... They are stacked and assembled together.

[0031] Electrolyte material BaZr was prepared using the sol-gel method. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δδ is the oxygen vacancy concentration parameter, representing the non-stoichiometric amount of oxygen atoms missing in the oxide, ranging from 0.1 to 0.5. Specifically, 0.4 mol of barium nitrate (Ba(NO3)2), 0.04 mol of zirconium oxynitrate (ZrO(NO3)2), 0.28 mol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O), 0.04 mol of yttrium nitrate hexahydrate (Y(NO3)3·6H2O), and 0.04 mol of ytterbium nitrate hexahydrate (Yb(NO3)3·6H2O) are weighed, and the above raw materials are dissolved in 200 ml of deionized water and stirred evenly to obtain solution A; 0 0.4 mol citric acid (CA) and 0.8 mol EDTA were dissolved in 80 ml ammonia water and stirred thoroughly until completely clear to obtain solution B. Solution B was slowly added to solution A, and the mixture was continuously heated and stirred until a homogeneous gel was formed. The gel was heated and kept at 230℃ in an oven for 240 minutes to obtain the precursor material. The precursor material was then placed in a muffle furnace and sintered at 1000℃ for 6 hours, and cooled at a rate of 3℃ / min to finally obtain BZCYYb powder material.

[0032] The anode support layer 4 is a NiO-BZCYYb composite material, i.e., a ceramic composite structure formed by sintering NiO powder and BZCYYb powder, wherein the mass percentage of NiO powder is 50-60 wt% and the mass percentage of BZCYYb powder is 40-50 wt%. In a preferred embodiment, the mass percentage of NiO powder is 55 wt% and the mass percentage of BZCYYb powder is 45 wt%. The anode functional layer 3 is also a NiO-BZCYYb composite material, with the mass percentage of NiO powder being 60-70 wt% and the mass percentage of BZCYYb powder being 30-40 wt%. In a preferred embodiment, the mass percentage of NiO powder is 65 wt% and the mass percentage of BZCYYb powder is 35 wt%. The electrolyte layer 2 is made of pure BZCYYb material. The NiO-BZCYYb composite powder and pure BZCYYb powder with different ratios were prepared into slurries according to conventional methods for preparing casting slurries (adding binders, plasticizers, solvents, etc.). Cast films were then prepared by casting process. The thickness of the anode support layer 4 casting film was controlled at 500 μm, the thickness of the anode functional layer 3 casting film was controlled at 30 μm, and the thickness of the electrolyte layer 2 casting film was controlled at 8-10 μm. The key parameters of the casting process are as follows: for the anode support layer 4, the casting blade height is 500-700 μm (preferably 600 μm); for the anode functional layer 3, the casting blade height is 40-60 μm (preferably 50 μm); and for the electrolyte layer 2, the casting blade height is set to 25-35 μm (preferably 30 μm). The substrate heating temperature for each layer is set to 40–60℃ (preferably 50℃), and the hot air purging temperature for each layer is controlled at 45–65℃ (preferably 55℃). This helps the slurry to dry evenly, prevents cracking, and avoids excessive volatilization or thermal degradation of organic components. The casting film belt movement speed is controlled at 0.15 cm / s to ensure that the slurry is evenly spread on the substrate surface, effectively avoiding uneven drying or local aggregation, and improving film surface consistency. The prepared anode support layer 4, anode functional layer 3, and electrolyte layer 2 casting films are stacked and assembled in structural order.

[0033] The method for preparing a proton conductor ceramic direct ammonia fuel cell according to the present invention further includes utilizing high entropy combination. A high-entropy alloy anode catalyst layer was prepared by screen printing of gold powder.

[0034] Aluminum (Al), iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu) powders are added to a high-energy ball mill and continuously ball-milled to ensure uniform mixing of the metal powders, resulting in FeCoNiCuAl precursor high-entropy alloy powder. This FeCoNiCuAl precursor high-entropy alloy powder is then placed in a strong alkaline solution for mixing and settling. This step is technically termed alkaline etching, and from a materials science perspective, it is a dealloying process. It utilizes the characteristic that Al reacts chemically with strong alkalis, while Fe, Co, Ni, and Cu do not react significantly under these conditions. This process selectively removes most of the Al component from the FeCoNiCuAl precursor high-entropy alloy powder (Al reacts with the alkaline solution to form water-soluble aluminates, which are released from the alloy system with the solution), and forms interconnected pores at the original Al sites, thus constructing a porous FeCoNiCu-based high-entropy alloy powder (which may contain residual Al). This porous structure is key to enhancing the catalytic activity of this invention, significantly increasing the specific surface area of ​​the high-entropy alloy and providing sufficient reaction interfaces and active sites for the ammonia decomposition reaction. Specifically, Ni, as the core active site for ammonia decomposition and hydrogen dissociation, can efficiently adsorb ammonia molecules and break NH bonds; Co, with its atomic radius similar to Ni, can embed into the Ni lattice to form Ni-Co dual active sites, reducing the adsorption strength of Ni on N atoms by regulating the electronic interaction between the two, thus inhibiting the formation of Ni3N from the root; Fe optimizes the electronic structure of the alloy surface, enhancing the kinetics of the entire ammonia decomposition adsorption-dissociation-desorption process; Cu, due to its low binding energy with N, can form a dispersion barrier on the alloy surface, blocking the direct contact between Ni and N. The four elements synergistically optimize the electronic structure and catalytic site distribution of the high-entropy alloy surface, effectively improving its non-noble metal catalytic activity in ammonia decomposition and anodic charge transfer processes. In a preferred embodiment, 1 mol each of Fe, Co, Ni, Cu, and Al metal powders are weighed, mixed in proportion, and then added to a high-energy ball mill for high-energy ball milling for 12 hours to form a uniform FeCoNiCuAl multi-element high-entropy alloy powder. It should be understood that the focus of the composition optimization of the high-entropy alloy catalyst layer described in this invention is not on strictly maintaining the equimolar ratio of each component in the final FeCoNiCu-based catalyst layer, but rather on the influence of the Al content and component distribution ratio of the FeCoNiCuAl precursor alloy on the subsequent dealloying pore structure formation, and the regulation of microstructure parameters such as porosity, pore size, and connectivity by alkaline etching, thereby optimizing ammonia decomposition activity and battery performance. Figure 3As shown, the SEM image on the left displays the microstructure of the high-entropy alloy. It can be seen that after alkaline etching to remove Al (i.e., the dealloying process), a significant porous activity-enhancing structure is formed on the surface of the high-entropy alloy. This is precisely the pore left in the original Al-occupying positions after the selective removal of Al during the dealloying process. This structure can provide abundant catalytic sites for the ammonia decomposition reaction, greatly improving the reaction contact efficiency. The elemental distribution and content detection results on the right show that the mass fractions of each element in the treated high-entropy alloy are: Al 1.65%, Fe 24.70%, Co 24.31%, Ni 24.73%, and Cu 24.61%, with a total of 100.00% of each metal element. This indicates that only a small amount of Al (a trace component that has not been completely reacted) remains after alkaline etching / dealloying treatment. The core FeCoNiCu high-entropy alloy components are completely preserved, and each component is evenly distributed in the alloy without local aggregation, which can ensure the stability and uniformity of catalytic activity.

[0035] Take 0.9g of the above high-entropy alloy powder and mix it evenly with 0.1g of ethyl cellulose. Then add 1.0g of terpineol as a solvent, add zirconia beads with diameters of 3mm and 5mm respectively and a mass ratio of 3:1, and place them in a high-speed ball mill and stir at a speed of 300r / min for 3h to obtain a screen printing paste with moderate viscosity and uniform dispersion. Apply the above-prepared high-entropy alloy screen printing paste evenly to the outer surface of the anode support layer 4 (i.e., the outer surface of the anode side of the stacked body) through a screen printing process. After forming according to the design pattern, dry it to complete the preliminary construction of the high-entropy alloy anode catalyst layer.

[0036] The method for preparing a proton conductor ceramic direct ammonia fuel cell according to the present invention further includes, in part, an electrolyte layer. 2. An integrated green body (four-layer green body stack) comprising the anode functional layer 3, the anode support layer 4, and the high-entropy alloy anode catalyst layer 5. Isostatic pressing and co-sintering .

[0037] The isostatic pressing (OSP) process parameters are: temperature 70℃, pressure 70MPa, and holding time 10min. OSP enhances the bonding force between layers, improves the overall density and mechanical integrity of the battery structure, and enhances its resistance to thermal shock. The OSP-pressed laminated films are then co-sintered in air using a multi-stage heating strategy. Specifically, the heating rate is 1℃ / min below 300℃ to slowly remove organic components from the slurry and prevent blistering or cracking of the film. Between 300-1200℃, the heating rate is set to 5℃ / min to ensure uniform sintering of the metal alloy and ceramic substrate, avoiding abnormal particle growth. Above 1200℃, the heating rate is reduced to 1℃ / min until reaching 1450℃ and holding for 5 hours to ensure a dense battery structure and prevent thermal stress cracking. The final sintering temperature of 1450℃ also enables the densification of the electrolyte material, improving the battery's airtightness and electrochemical stability. In particular, this invention adopts an integrated multi-layer structure construction route of casting-lamination-screen printing-isostatic pressing-co-sintering to achieve precise superposition, uniform bonding and dense molding of each functional layer of the fuel cell, improve the airtightness and overall mechanical strength of the battery, and meet the requirements of large-scale manufacturing.

[0038] The method for preparing a proton conductor ceramic direct ammonia fuel cell according to the present invention finally includes utilizing barium cobalt iron zirconium. The cathode 1 is formed by wet spraying of yttrium (BCFZY) powder material.

[0039] Preparation of cathode material BaCo using sol-gel method 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δδ is the oxygen vacancy concentration parameter, representing the non-stoichiometric amount of oxygen atoms missing in the oxide, ranging from 0.1 to 0.5. Specifically, metal nitrate raw materials are weighed in a molar ratio of Ba:Co:Fe:Zr:Y = 1:0.4:0.4:0.1:0.1. 10.45g of barium nitrate (Ba(NO3)2), 4.66g of cobalt nitrate hexahydrate (Co(NO3)2·6H2O), 6.46g of ferric nitrate nonahydrate (Fe(NO3)3·9H2O), 1.72g of zirconium oxynitrate (ZrO(NO3)2), and 1.532g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) are added sequentially to a beaker. In another beaker, 33.62g of citric acid and oxaloacetic acid tetraacetic acid (E 23.37g of DTA was added, followed by 25% ammonia solution and stirred thoroughly until the solution was completely clear, yielding a sol solution. The sol solution was then transferred to a beaker containing metal nitrates and heated and stirred for about 3 hours until a stable and homogeneous gel was formed. The gel was placed in an oven and heated at 230°C for 240 minutes to obtain a fluffy and uniform cathode precursor material. The cathode precursor material was placed in a muffle furnace and heated to 1000°C and held for 6 hours. Subsequently, the temperature was slowly lowered at a rate of 3°C / min to finally obtain a loose and porous BCFZY cathode powder material.

[0040] The above-mentioned BCFZY powder is used as the cathode material. It is uniformly coated on the top surface of the co-sintered electrolyte layer 2 by a wet spraying process, and the cathode coating thickness is controlled to be about 20 μm. Finally, the cathode is subjected to electrode sintering (e.g., 700~1000℃, preferably 950℃) and full cell reduction activation (e.g., H2 atmosphere) to obtain a proton conductor ceramic direct ammonia fuel cell with complete structure.

[0041] like Figure 4 As shown, a) is a SEM image of the overall battery structure at low rate, clearly showing the FeCoNiCu anode catalyst layer 5 and Ni-BZCYYb anode support layer 4 at the bottom of the battery; b) is a high-rate cross-sectional SEM image of a part of the battery, further demonstrating the interface bonding state between the BCFZY cathode 1, BZCYYb electrolyte layer 2, Ni-BZCYYb anode functional layer 3, and Ni-BZCYYb anode support layer 4. Each layer is free from peeling, pores, and cracks, and is tightly bonded, indicating that the integrated fabrication process of this invention can achieve good composite of multi-layer battery structures, and the materials have excellent thermal and mechanical matching.

[0042] Electrochemical performance tests were conducted on the proton conductor ceramic direct ammonia fuel cell according to the present invention under the following conditions: 500-650°C, air as the cathode oxidant, and wet hydrogen / wet ammonia as the anode fuel.

[0043] like Figure 5As shown, a) are the voltage-current density (IV) and power-current density (IP) curves when H2 is used as fuel, and b) are the battery performance curves when NH3 is used as fuel. Under the test condition of 650℃, the peak power density of the battery when using H2 as fuel reaches 1.84 W·cm³. -2 When using NH3 as fuel, it can still stably output a peak power density of 1.28 W·cm³. -2 As can be seen from the curve trend, the output performance of the battery at different temperatures of 500℃, 550℃, 600℃ and 650℃ shows a stable increasing trend with the increase of temperature, without any sudden change or decay in performance, demonstrating good output performance and thermal response consistency.

[0044] like Figure 6 As shown, a is the Nyquist curve at different temperatures when H2 is used as fuel, and b is the Nyquist curve at different temperatures when NH3 is used as fuel. Under different fuels (H2 / NH3) and different temperatures (500-650℃), the impedance (area of ​​the semicircle of the curve) shows a stable decreasing trend with increasing temperature. In particular, the impedance is the lowest at 650℃ with NH3 fuel, indicating that the high-entropy alloy anode catalyst layer can effectively reduce the total impedance of the battery and significantly improve the ammonia decomposition reaction rate and interfacial charge transport capability of the battery.

[0045] The battery with a high-entropy alloy anode catalyst layer constructed according to the present invention was compared with a Ni-BZCYYb substrate control battery without the catalyst layer.

[0046] like Figure 7 As shown, comparing the voltage change trends over time of the battery (HEA anode) with the high-entropy alloy catalyst layer of this invention and the control battery (Bare anode) without the catalyst layer, the voltage of the control battery without the catalyst layer shows a rapid decreasing trend with increasing operating time and a high decay rate. In contrast, the voltage of the battery with the high-entropy alloy catalyst layer remains basically constant within 100 hours with no significant decay. This fully demonstrates that the high-entropy alloy catalyst layer can effectively suppress the nitriding phenomenon of Ni-based anodes, maintain the integrity of the anode structure and electrochemical performance, and significantly improve the long-term operating stability of the battery in an ammonia environment.

[0047] like Figure 8 As shown, comparing the button cell with the high-entropy alloy catalyst layer of the present invention with the control Ni-BZCYYb button cell without the catalyst layer, the overall structural integrity of the battery was not affected after adding the high-entropy alloy anode catalyst layer. The catalyst layer and the base battery achieved good integrated composite, and the battery had good appearance and formability. This indicates that the high-entropy alloy catalyst layer preparation process of the present invention has excellent compatibility with the structure of the button cell and can be directly applied to the structural modification and performance improvement of conventional fuel cells.

[0048] Thus, this invention employs a porous FeCoNiCu-based high-entropy alloy, formed by dealloying a FeCoNiCuAl precursor alloy, as the anode catalyst layer. This layer is integrated onto the bottom of the anode support via screen printing, significantly improving the catalytic efficiency of ammonia decomposition and effectively suppressing the deactivation problem caused by nitriding reactions in traditional Ni anodes under ammonia atmosphere. Specifically, HEA-ACL exhibits excellent ammonia decomposition capability and anti-nitriding performance in a high-temperature ammonia environment, significantly inhibiting the formation of metal nitrides (such as Ni3N) from Ni particles. Furthermore, by controlling the precursor alloy ratio and dealloying conditions to optimize the pore structure and surface charge structure, the anode interface reactivity is enhanced, thereby extending the stable operating time of the fuel cell. This structure, by introducing a multi-level gradient anode structure of catalysis-function-support, optimizes the proton transport path and reaction interface, achieving a synergy of high performance and high stability. The core lies in using an alkaline etching / dealloying route with the FeCoNiCuAl precursor alloy to prepare the porous FeCoNiCu-based catalyst layer, and optimizing the pore structure by controlling the precursor alloy ratio and dealloying conditions to improve ammonia decomposition and anode-side charge transfer efficiency. This invention employs an integrated fabrication process of casting-layering-screen printing-co-sintering, which is simple, highly reproducible, and has good prospects for process scale-up and engineering applications. The constructed HEA-ACL / Ni-BZCYYb / BZCYYb / BCFZY full cell structure can achieve a peak power density of 1.84 W·cm³ at 650°C using hydrogen as fuel. -2 When using ammonia as fuel, it can still stably output a peak power density of 1.28 W·cm³. -2 This technology outperforms existing Fe-CeOx systems. A 100-hour stability test showed that the HEA catalyst layer effectively maintains the integrity of the anode structure and electrochemical performance, with a significantly lower decay rate than the control sample without the catalyst layer, demonstrating the excellent ammonia resistance and long-term operational reliability of this invention. This structure and process not only improve the overall energy density and stability of the battery but also provide a new solution for the practical application of proton ceramic fuel cells in distributed ammonia energy systems.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A proton conductor ceramic direct ammonia fuel cell, characterized in that, It includes an electrolyte layer and a cathode and an anode located on opposite sides thereon. The anode is a gradient anode structure composed of an anode functional layer, an anode support layer, and a high-entropy alloy anode catalyst layer. The cathode is made of BCFZY material, the electrolyte layer is made of BZCYYb material, the anode support layer and the anode functional layer are both NiO-BZCYYb composite materials, and the high-entropy alloy anode catalyst layer is a porous FeCoNiCu-based structure formed by dealloying FeCoNiCuAl precursor alloy.

2. The proton conductor ceramic direct ammonia fuel cell according to claim 1, characterized in that, The dealloying process selectively removes most of the Al component from the FeCoNiCuAl precursor alloy, forming a connected porous structure at the original Al sites.

3. The proton conductor ceramic direct ammonia fuel cell according to claim 1, characterized in that, The BZCYYb is BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ The BCFZY is BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ δ is between 0.1 and 0.

5.

4. The proton conductor ceramic direct ammonia fuel cell according to claim 1, characterized in that, The anode support layer contains 50-60 wt% NiO powder and 40-50 wt% BZCYYb powder; the anode functional layer contains 60-70 wt% NiO powder and 30-40 wt% BZCYYb powder.

5. A method for preparing a proton conductor ceramic direct ammonia fuel cell as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1, using BZCYYb powder, cast films of anode support layer, anode functional layer and electrolyte layer are prepared by casting process and then stacked and assembled in sequence; S2, using high-entropy alloy powder to form a high-entropy alloy anode catalyst layer on the outer surface of the anode support layer through screen printing process, and then obtaining an integrated green body after drying; S3 involves isostatic pressing of the integrated green body, followed by co-sintering. S4 utilizes BCFZY powder to form a cathode on the electrolyte layer through a wet spraying process. After sintering and full-cell reduction and activation treatment, a complete fuel cell is obtained.

6. The preparation method according to claim 5, characterized in that, The parameters of the casting process in step S1 are as follows: the casting blade height of the anode support layer is 500~700μm, the casting blade height of the anode functional layer is 40~60μm, the casting blade height of the electrolyte layer is 25~35μm, the substrate heating temperature of each layer is 45~55℃, the hot air purging temperature of each layer is 50~60℃, and the casting film belt movement speed is 0.1~0.2cm / s.

7. The preparation method according to claim 5, characterized in that, The preparation process of the high-entropy alloy powder in step S2 is as follows: Fe, Co, Ni, Cu and Al metal powders are mixed and then ball-milled for 10-12 hours to obtain FeCoNiCuAl precursor high-entropy alloy powder; the FeCoNiCuAl precursor high-entropy alloy powder is placed in a strong alkaline solution for dealloying treatment to remove most of the Al component and form porous FeCoNiCu-based high-entropy alloy powder.

8. The preparation method according to claim 5, characterized in that, The screen printing paste mentioned in step S2 is made by mixing high-entropy alloy powder, ethyl cellulose and terpineol, wherein the mass ratio of high-entropy alloy powder to ethyl cellulose is 8~10:1 and the mass ratio of high-entropy alloy powder to terpineol is 0.8~1.0:1; during preparation, zirconia beads with a diameter of 3~5 mm and a mass ratio of 3:1 are added and stirred at a speed of 250~350 r / min for 2~4 h.

9. The preparation method according to claim 5, characterized in that, The parameters for the isostatic pressing process in step S3 are: temperature 50~90℃, pressure 50~90MPa, and holding time 5~15min.

10. The preparation method according to claim 5, characterized in that, The co-sintering described in step S3 adopts a multi-stage heating strategy: when the temperature is below 300℃, the heating rate is 0.5~1.5℃ / min; when the temperature is in the range of 300~1200℃, the heating rate is 4~6℃ / min; when the temperature is above 1200℃, the heating rate is 0.5~1.5℃ / min, the final sintering temperature is 1400~1500℃, and the holding time is 4~6h.

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