A high-performance high-entropy alloy-ceramic composite nanostructured anode material and its application in solid oxide fuel cells

Abstract

The present invention discloses a high-entropy alloy-ceramic composite nanostructured anode material. The high-entropy alloy is an alloy formed by equimolar proportions of five metal elements: Fe, Ni, Co, Cu, and Mo. The mixed ion-electronic conductor ceramic material is cerium oxide doped with 10-20 mol% of lanthanide metal oxide gadolinium oxide. The high-entropy alloy with excellent catalytic performance and flexible and variable composition and the mixed ion-electronic conductor ceramic material are spontaneously and orderly compounded in a solution. By regulating the ratio of the two, the composite powder particles are refined and exhibit a uniformly distributed nanostructure. The composite is directly applied to solid oxide fuel cells using an electrode preparation process that does not require a sintering step. Compared with pure high-entropy alloy electrodes and sintered electrodes, the performance and operational stability of the battery are significantly improved. The entire preparation process has low raw material costs and the preparation method is simple to operate, providing good application prospects for high-entropy alloys in solid oxide fuel cells.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide fuel cells, and in particular to a high entropy alloy-ceramic composite nanostructured anode material, a preparation method thereof, and applications thereof. Background Art

[0002] Solid oxide fuel cells (SOFCs) are clean and efficient energy conversion devices that directly convert the chemical energy in fuels into electrical energy. Unconstrained by the Carnot cycle effect, they can achieve energy conversion efficiencies exceeding 80%, offering advantages such as wide fuel adaptability, high reliability, and environmental friendliness. SOFCs have a sandwich structure, consisting of a porous anode and cathode with a dense electrolyte located in between. The anode is a crucial component of SOFCs, serving as the site for electrochemical oxidation reactions of fuel gases such as hydrogen. Its performance and microstructure have a crucial impact on the overall performance of the cell. Currently, the most widely studied anode material is a Ni-based metal-ceramic composite. However, Ni metal particles undergo grain growth at high temperatures, resulting in agglomeration and coarsening, reducing porosity and the three-phase reaction interface, significantly reducing the catalytic activity of the anode. Therefore, the development of new, efficient and stable SOFC anode materials is a current research hotspot.

[0003] High-entropy alloys (HEAs) are alloys composed of five or more metallic elements, with the atomic fraction of each major element ranging from 5% to 35%. Compared to conventional catalytic materials composed of two or three metallic elements, HEAs not only possess superior physical, chemical, surface, and electromagnetic properties, but also exhibit highly stable catalytic activity. By determining the type and composition of these elements, the active sites of HEAs catalysts can be optimized for specific purposes, yielding highly effective catalytic alloys. While conventional alloy synthesis methods, such as smelting and processing, can effectively prepare bulk HEAs, the preparation process typically involves high pressure, high temperature, and a reducing environment, resulting in increased manufacturing costs and energy consumption, and is unsuitable for the preparation of HEAs with nanostructures. Solid oxide fuel cells (SOFCs) typically operate under high temperatures and current loading, making the design of the anode material's nanostructure and the regulation of its microstructural stability crucial. Therefore, the simple, efficient, and controllable preparation of HEA nanomaterials and their application in SOFCs remain challenging. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a high-entropy alloy-ceramic composite nanostructured anode material and a preparation method thereof, and adopts an electrode preparation process that does not require a sintering step to directly apply it to the anode of a solid oxide fuel cell. While retaining the high-entropy alloy-ceramic composite anode nanostructure, the anode has a rich three-phase reaction zone length, which significantly improves the performance and operating stability of the single cell compared to pure high-entropy alloy electrodes and sintered electrodes.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A high entropy alloy-ceramic composite nanostructured anode material, wherein the composite nanostructured anode material is mainly composed of a high entropy alloy and a mixed ion-electronic conductor ceramic material, wherein the weight of the high entropy alloy accounts for 60-80% of the total weight of the anode material.

[0007] Furthermore, the high entropy alloy is an alloy formed by equimolar proportions of five metal elements: Fe, Ni, Co, Cu, and Mo; and the mixed ion electronic conductor ceramic material is cerium oxide doped with 10-20 mol% of lanthanide metal oxide gadolinium oxide.

[0008] The present invention provides a method for preparing the above-mentioned high entropy alloy-ceramic composite nanostructured anode material, which specifically comprises the following steps:

[0009] (1) Dissolve the soluble metal salts of five metal elements, Fe, Ni, Co, Cu, and Mo, and the soluble nitrates of Ce and Gd in deionized water according to the required stoichiometric ratio, add a chelating agent to form a complex between different metal ions and the chelating agent, then add ammonia water to adjust the pH value of the solution to 6-8, and stir thoroughly until all components are completely dissolved;

[0010] (2) heating the solution obtained in step (1) until the solvent is completely evaporated, drying it in an oven, and then grinding it to obtain a precursor of a high entropy alloy-ceramic composite anode material;

[0011] (3) The high entropy alloy-ceramic composite anode material precursor obtained in step (2) is transferred to a muffle furnace for heat treatment to obtain a high entropy alloy-ceramic oxide powder, which is then placed in a tube furnace and heated to 700-1000°C in a nitrogen atmosphere, and hydrogen is introduced for reduction to obtain a high entropy alloy-ceramic composite nanostructured anode material.

[0012] Furthermore, the chelating agents used in step (1) are citric acid and ethylenediaminetetraacetic acid, and the molar ratio of citric acid, ethylenediaminetetraacetic acid to metal cations in the solution is (1-2):(1-2):1.

[0013] Furthermore, in step (2), the temperature for evaporating the solvent is 60-90°C, the temperature for drying in the oven is 150-250°C, and the drying time is 10-15 hours.

[0014] Furthermore, in step (3), the heat treatment temperature of the high entropy alloy-ceramic composite anode material precursor is 400-900° C., the heat treatment time is 2-5 hours, and the hydrogen reduction time is 1-4 hours.

[0015] The present invention also provides an application of a high entropy alloy-ceramic composite nanostructured anode material in a solid oxide fuel cell, which specifically includes the following steps:

[0016] (1) Grinding the high entropy alloy-ceramic composite anode nanostructured anode material and the binder to obtain an anode slurry;

[0017] (2) The anode slurry obtained in step (1) is uniformly coated on an electrolyte sheet with a buffer layer spin-coated thereon, and heat-treated in a nitrogen atmosphere to obtain an electrolyte-supported half-cell, which is then combined with a cathode material to obtain a solid oxide fuel cell prepared with a high-entropy alloy-ceramic composite nanostructured anode material.

[0018] Furthermore, the mass ratio of the high entropy alloy-ceramic composite nanostructured anode material to the binder described in step (1) is 7:3; the binder is a mixture of terpineol and ethyl cellulose, the ethyl cellulose accounts for 4-10% of the total mass of the binder, and the binder accounts for 20-50% of the total mass of the anode slurry.

[0019] Furthermore, the heat treatment temperature in step (2) is 150-250° C., and the time is 2-5 hours.

[0020] The beneficial effects of the present invention are:

[0021] (1) A high entropy alloy with excellent catalytic performance and flexible composition is combined with a mixed ion-electronic conductor ceramic material to obtain a uniformly distributed and nanostructured anode material. The anode has a rich three-phase reaction zone length and exhibits excellent catalytic activity when applied to solid oxide fuel cells. Compared with pure high entropy alloy electrodes and sintered electrodes, the performance of single cells is significantly improved.

[0022] (2) The high entropy alloy and ceramic metal oxide are spontaneously and orderly compounded in the form of a solution, which builds a strong interaction between the high entropy alloy and the ceramic metal oxide, ensuring the stability of the nanostructure. The electrode preparation process does not require a sintering step and retains the original fine structure of the anode. Compared with pure high entropy alloy electrodes and sintered electrodes, the operating stability of the single cell is significantly improved, providing a good application prospect for high entropy alloys in solid oxide fuel cells.

[0023] (3) High entropy alloys are formed from non-precious metal elements, and the raw materials are widely available. The preparation process of high entropy alloy-ceramic composite nanostructured anode materials and their solid oxide fuel cells is simple and stable, and has good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 XRD patterns of the high entropy alloy-ceramic composite nanostructured anode material FNCCM-GDC (7:3) prepared in Example 1 and the pure high entropy alloy FNCCM powder prepared in Comparative Example 1.

[0025] Figure 2 These are SEM images of the high entropy alloy-ceramic composite nanostructured anode material FNCCM-GDC (7:3) prepared in Example 1 and the pure high entropy alloy FNCCM powder prepared in Comparative Example 1.

[0026] Figure 3 HAADF image and element distribution map of the high entropy alloy-ceramic composite nanostructured anode material FNCCM-GDC (7:3) prepared in Example 1.

[0027] Figure 4 It is a comparison chart of the power density curves of the solid oxide fuel cells of Application Example 1, Application Comparative Example 1 and Application Comparative Example 2.

[0028] Figure 5 It is a comparison chart of the stability curves of the solid oxide fuel cells of Application Example 1, Application Comparative Example 1 and Application Comparative Example 2.

[0029] Figure 6 This is a cross-sectional SEM image of a solid oxide fuel cell after testing using a high entropy alloy-ceramic composite nanostructured anode material as the anode in Application Example 1. DETAILED DESCRIPTION

[0030] In order to make the contents of the present invention easier to understand, the technical solutions of the present invention are further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0031] Example 1 FNCCM-GDC (7:3)

[0032] The metal elements selected for the high entropy alloy are Fe, Ni, Co, Cu, and Mo, and the high entropy alloy accounts for 70% of the total mass of the anode material.

[0033] (1) Weigh 4.25gFe(NO3)3·9H2O, 3.06gNi(NO3)2·6H2O, 3.06gCo(NO3)2·6H2O, 2.54gCu(NO3)2·3H2O, 1.89g(NH4)6Mo7O 24·4H2O, 0.39gGd(NO3)3·6H2O, and 3.39gCe(NO3)3·6H2O were dissolved in an appropriate amount of deionized water to form an iron-nickel-cobalt-copper-molybdenum-gadolinium-cerium solution. Subsequently, 17.64g citric acid and 17.89g ethylenediaminetetraacetic acid were added to chelate the metal ions. 37ml ammonia water was added to adjust the solution pH to 7, and the solution was stirred continuously to fully dissolve the components.

[0034] (2) The solution obtained in step (1) is heated to 90°C to gradually evaporate the solvent. After the solvent is completely evaporated, the solution is placed in an oven and gently dried at 200°C for 10 h. The obtained sample is collected and ground to obtain a precursor of a high entropy alloy-ceramic composite anode material.

[0035] (3) The high entropy alloy-ceramic composite anode material precursor obtained in step (2) was transferred to a muffle furnace and heat-treated at 850 °C for 3 hours to obtain a high entropy alloy-ceramic oxide powder, which was placed in a tube furnace and heated to 800 °C in a nitrogen atmosphere, and then hydrogen was introduced for reduction for 1 hour to obtain a high entropy alloy-ceramic composite nanostructured anode material FNCCM-GDC (7:3).

[0036] Example 2 FNCCM-GDC (6:4)

[0037] The metal elements selected for the high entropy alloy are Fe, Ni, Co, Cu, and Mo, and the high entropy alloy accounts for 60% of the total mass of the anode material.

[0038] (1) Weigh 3.64gFe(NO3)3·9H2O, 2.62gNi(NO3)2·6H2O, 2.62gCo(NO3)2·6H2O, 2.18gCu(NO3)2·3H2O, 1.59g(NH4)6Mo7O 24 ·4H2O, 0.52gGd(NO3)3·6H2O, and 4.52gCe(NO3)3·6H2O were dissolved in an appropriate amount of deionized water to form an iron-nickel-cobalt-copper-molybdenum-gadolinium-cerium solution. Subsequently, 16.31g citric acid and 16.54 ethylenediaminetetraacetic acid were added to chelate the metal ions. 34ml ammonia water was added to adjust the solution pH to 7. Stir continuously to fully dissolve all the components.

[0039] (2) The solution obtained in step (1) is heated to 90°C. After the solvent is completely evaporated, the solution is placed in an oven and gently dried at 200°C for 10 h. The obtained sample is collected and ground to obtain a precursor of a high entropy alloy-ceramic composite anode material;

[0040] (3) The high entropy alloy-ceramic composite anode material precursor obtained in step (2) was transferred to a muffle furnace and heat-treated at 850 °C for 3 h to obtain a high entropy alloy-ceramic oxide powder, which was placed in a tube furnace and heated to 800 °C in a nitrogen atmosphere, and then hydrogen was introduced for reduction for 1 h to obtain a high entropy alloy-ceramic composite nanostructured anode material FNCCM-GDC (6:4).

[0041] Comparative Example 1 FNCCM

[0042] Weigh 6.07gFe(NO3)3·9H2O, 4.37gNi(NO3)2·6H2O, 4.37gCo(NO3)2·6H2O, 3.63gCu(NO3)2·3H2O, 2.71g(NH4)6Mo7O 24 Dissolve 4H2O in an appropriate amount of deionized water, then add 21.64g citric acid and 21.94g ethylenediaminetetraacetic acid to chelate the metal ions, then add 45ml ammonia to adjust the solution pH to 7, and stir continuously to fully dissolve all the ingredients;

[0043] (2) The solution obtained in step (1) is heated to 90°C. After the solvent is completely evaporated, the solution is placed in an oven and gently dried at 200°C for 10 h. The obtained sample is collected and ground to obtain a precursor of a high entropy alloy.

[0044] (3) The high entropy alloy precursor obtained in step (2) was transferred to a muffle furnace and heat treated at 850 °C for 3 hours to obtain a high entropy alloy powder, which was placed in a tubular furnace and heated to 800 °C in a nitrogen atmosphere, and then hydrogen was introduced for reduction for 1 hour to obtain a pure high entropy alloy anode material FNCCM.

[0045] Application Example 1

[0046] 0.7 g of the high entropy alloy-ceramic composite anode powder prepared in Example 1 was weighed into a mortar, 0.3 g of a binder (formed by mixing 48 g of terpineol and 2 g of ethyl cellulose) was added and ground evenly to obtain an anode slurry. The prepared anode slurry was evenly coated on the Gd spin-coated 0.1 Ce 0.9 O 1.95 Buffer layer (Sc2O3) 0.1 (CeO2) 0.01 (ZrO2) 0.89 The electrolyte sheet was heated to 200 °C in a nitrogen atmosphere for 3 h to obtain an electrolyte-supported half-cell prepared with FNCCM-GDC (7:3) anode material. 0.6 Sr 0.4 Co 0.2 Fe 0.8O3 cathode materials are combined to prepare a full battery.

[0047] Comparative Application Example 1

[0048] 0.7 g of the pure high entropy alloy anode powder prepared in Comparative Example 1 was weighed into a mortar, 0.3 g of a binder (formed by mixing 48 g of terpineol and 2 g of ethyl cellulose) was added and ground evenly to obtain an anode slurry. The prepared anode slurry was evenly coated on the spin-coated Gd 0.1 Ce 0.9 O 1.95 Buffer layer (Sc2O3) 0.1 (CeO2) 0.01 (ZrO2) 0.89 The electrolyte sheet was heated to 200 °C in a nitrogen atmosphere for 3 h to obtain an electrolyte-supported half-cell made of FNCCM anode material. 0.6 Sr 0.4 Co 0.2 Fe 0.8 O3 cathode materials are combined to prepare a full battery.

[0049] Application Comparative Example 2

[0050] 0.7 g of the high entropy alloy-ceramic composite anode powder prepared in Example 1 was weighed into a mortar, 0.3 g of a binder (formed by mixing 48 g of terpineol and 2 g of ethyl cellulose) was added and ground evenly to obtain an anode slurry. The prepared anode slurry was evenly coated on the Gd spin-coated 0.1 Ce 0.9 O 1.95 Buffer layer (Sc2O3) 0.1 (CeO2) 0.01 (ZrO2) 0.89 The electrolyte sheet was placed in a tube furnace and heated to 950 °C in a nitrogen atmosphere for 3 h to obtain an electrolyte-supported half-cell prepared by sintering FNCCM-GDC (7:3) anode material. 0.6 Sr 0.4 Co 0.2 Fe 0.8 O3 cathode materials are combined to prepare a full battery.

[0051] Figure 1 The XRD patterns of FNCCM-GDC (7:3) powders of Example 1 and Comparative Example 1 FNCCM are shown. The experimental results show that the prepared anode material consists of a single solid solution phase of FeNiCoCuMo and a phase of GDC, with no obvious impurity phase peaks appearing, indicating the successful preparation of the high-entropy alloy and the good chemical compatibility of FeNiCoCuMo and GDC.

[0052] Figure 2 These are SEM images of the FNCCM-GDC (7:3) powders of Example 1 and Comparative Example 1. It can be seen from the figure that after the high-entropy alloy is compounded with the mixed ion-electronic conductor ceramic material, the powder particles are refined, the particle size is significantly reduced, the specific surface area is increased, and the length of the three-phase reaction zone of high-entropy alloy / GDC / fuel gas is increased.

[0053] Figure 3 The HAADF image and element distribution diagram of FNCCM-GDC (7:3) in Example 1 show that uniformly mixed nanoparticles were prepared, and the GDC particles coated on the surface of the high-entropy alloy can effectively inhibit the growth and coarsening of the high-entropy alloy nanoparticles.

[0054] Figure 4 The power density curves of the solid oxide fuel cells of Example 1, Comparative Example 1, and Comparative Example 2 are compared. A single cell using an unsintered high-entropy alloy-ceramic composite nanostructured anode material as the anode can achieve 1.09 W·cm at 800°C in a hydrogen atmosphere. -2 The maximum output power density is higher than that of pure high-entropy alloy electrodes and sintered electrodes, proving that the high-entropy alloy-ceramic composite nanostructured anode material has good catalytic activity as an anode.

[0055] Figure 5 The stability curves of the solid oxide fuel cells of Example 1, Comparative Example 1 and Comparative Example 2 are compared. -2 The current polarization is 50 h. It can be seen from the figure that the attenuation rate of the solid oxide fuel cell prepared in Example 1 is 0.02% / h after 50 h, while the attenuation rates of the solid oxide fuel cells prepared in Comparative Examples 1 and 2 are 0.08% and 0.12% / h after 50 h, respectively. In comparison, the solid oxide fuel cell prepared in Example 1 has excellent long-term operation stability, indicating that the high-entropy alloy-ceramic composite nanostructured anode material and the electrode preparation method without high-temperature sintering can effectively improve the operation stability of the single cell.

[0056] Figure 6 This is a cross-sectional SEM image of the solid oxide fuel cell after testing using Example 1. The anode and cathode of the single cell are both loose and porous, the electrolyte structure is dense, and the interfaces between the anode, isolation layer, and electrolyte are tightly bonded without any cracking or faulting.

[0057] The above specific embodiments are further explanations of the technical solutions and beneficial effects of the present invention, and are not intended to limit the implementation methods. All equivalent changes and modifications made within the scope of the present invention should fall within the scope of the present invention.

Claims

1. A method for preparing a high entropy alloy-ceramic composite nanostructured anode material, characterized by: The composite nanostructured anode material is mainly composed of a high-entropy alloy and a mixed ion-electronic conductor ceramic material, wherein the weight of the high-entropy alloy accounts for 60-80% of the total weight of the anode material, and the high-entropy alloy is an alloy formed by equimolar proportions of five metal elements: Fe, Ni, Co, Cu, and Mo; and the mixed ion-electronic conductor ceramic material is cerium oxide doped with 10-20 mol% of lanthanide metal oxide gadolinium oxide. The preparation method of the composite nanostructured anode material includes the following steps: (1) Dissolve the soluble metal salts of five metal elements, Fe, Ni, Co, Cu, and Mo, and the soluble nitrates of Ce and Gd in deionized water according to the required stoichiometric ratio, add a chelating agent to form a complex between different metal ions and the chelating agent, then add ammonia water to adjust the pH value of the solution to 6-8, and stir thoroughly until all components are completely dissolved; (2) heating the solution obtained in step (1) until the solvent is completely evaporated, drying it in an oven, and then grinding it to obtain a precursor of a high entropy alloy-ceramic composite anode material; (3) The high entropy alloy-ceramic composite anode material precursor obtained in step (2) is transferred to a muffle furnace for heat treatment to obtain a high entropy alloy-ceramic oxide powder, which is then placed in a tubular furnace and heated to 700-1000°C in a nitrogen atmosphere, and hydrogen is introduced for reduction to obtain a high entropy alloy-ceramic composite nanostructured anode material.

2. The preparation method according to claim 1, wherein: The chelating agents in step (1) are citric acid and ethylenediaminetetraacetic acid, and the molar ratio of citric acid, ethylenediaminetetraacetic acid to metal cations in the solution is (1-2):(1-2):

1.

3. The preparation method according to claim 1, wherein: In step (2), the temperature for evaporating the solvent is 80-90°C, the temperature for drying in the oven is 150-250°C, and the drying time is 10-15 hours.

4. The preparation method according to claim 1, wherein: In step (3), the heat treatment temperature of the high entropy alloy-ceramic composite anode material precursor is 400~900℃, the heat treatment time is 2~5 hours, and the hydrogen reduction time is 1~4 hours.

5. A solid oxide fuel cell, characterized in that: A high entropy alloy-ceramic composite nanostructured anode material is obtained by using the preparation method of a high entropy alloy-ceramic composite nanostructured anode material as described in claim 1.

6. The method for preparing a solid oxide fuel cell according to claim 5, wherein: The following steps are involved: (1) Grinding the high entropy alloy-ceramic composite nanostructured anode material and the binder to obtain an anode slurry; (2) The anode slurry obtained in step (1) is uniformly coated on an electrolyte sheet with a buffer layer spin-coated thereon, and heat-treated in a nitrogen atmosphere to obtain an electrolyte-supported half-cell, which is then combined with a cathode material to obtain a solid oxide fuel cell prepared with a high-entropy alloy-ceramic composite nanostructured anode material.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the high entropy alloy-ceramic composite nanostructured anode material to the binder described in step (1) is 7:3; the binder is a mixture of terpineol and ethyl cellulose, wherein the ethyl cellulose accounts for 4-10% of the total mass of the binder; and the binder accounts for 20-50% of the total mass of the anode slurry.

8. The preparation method according to claim 6, characterized in that: The heat treatment temperature in step (2) is 150-250° C. and the time is 2-5 hours.

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