Preparation method of high-performance nickel-based nano composite anode suitable for batch production of solid oxide fuel cell

Abstract

The invention discloses a preparation method of a high-performance nickel-based nano composite anode of a solid oxide fuel cell, which is suitable for batch production. The composite anode is composed of NiO and a rare earth doped cerium oxide material, and rare earth elements are selected from one or more of Gd, Sm, Y, La, Pr and Nd. The powder is prepared by a coprecipitation method, soluble salt solutions are mixed, a precipitant is added, the mixture is fully stirred to obtain a hydroxide precursor, and two phases are uniformly compounded on the nanoscale after heat treatment. According to the method, raw materials are mixed on the atomic scale, and a nano composite structure with strong interface bonding is formed. The solid oxide fuel cell anode is constructed by adopting a process without high-temperature sintering, a fine nano composite structure and interface interaction of the solid oxide fuel cell anode are reserved, agglomeration and growth of nickel particles in the cell operation process are effectively inhibited, and the anode shows excellent electrochemical performance and operation stability.

Description

Technical Field

[0001] This invention relates to the field of solid oxide fuel cell technology, and more specifically to a method for preparing a nickel-based nanocomposite anode for solid oxide fuel cells that is suitable for mass production and has high performance. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are all-solid-state energy conversion devices that can directly and efficiently convert the chemical energy of fuel into electrical energy. They are not limited by the Carnot cycle, have high theoretical efficiency, and possess outstanding advantages such as strong fuel adaptability and environmental friendliness, making them an important component of future clean energy systems. The performance of SOFCs largely depends on the electrochemical catalytic activity and microstructural stability of their anode materials. Among numerous anode materials, metal-ceramic composites composed of metallic nickel and rare-earth-doped cerium oxide have become one of the most promising anode materials in the field of medium- and low-temperature SOFCs due to their excellent catalytic activity in hydrogen oxidation reactions, superior mixed conductivity, and chemical compatibility with commonly used electrolytes. In the material preparation process, uniformly and tightly compositing NiO and rare-earth-doped cerium oxide at the nanoscale can significantly expand the three-phase reaction area of ​​the anode, thereby improving electrode reaction kinetics and battery output performance. However, the preparation of this ideal nanocomposite anode and its structural stability under SOFC operating conditions face severe challenges. Currently, the main method for batch preparation of such composite powders is mechanical mixing, which involves physically mixing pre-synthesized NiO powder with cerium oxide-doped metal-ceramic powder. While this method is simple, its mixing uniformity is severely limited by the particle size and morphology of the original powder, and it is difficult to achieve uniform dispersion and close contact of the two phases at the nanoscale. More importantly, mechanical mixing cannot achieve strong interactions between the two phases at the interface, making the composite material prone to nickel particle migration, agglomeration, and coarsening during subsequent high-temperature battery operation, leading to a sharp decrease in the anode active surface area and rapid degradation of battery performance. The sol-gel method can improve the stability of the powder structure by enhancing the strong interfacial bonding between composites, but its large-scale, low-cost production limits its practical application in solid oxide fuel cells. Furthermore, using high-temperature sintering to construct the prepared nanoparticles as solid oxide fuel cell anodes easily destroys their original fine structure, leading to anode coarsening and thus reducing the catalytic activity of the electrode. Therefore, the mass production of nanoscale nickel-based composite powders with strong interfacial interactions and the achievement of high structural stability during electrode construction and battery operation are of great significance for the stable development of solid oxide fuel cell technology. Summary of the Invention

[0003] In view of the shortcomings of the prior art, this invention provides a method for preparing a high-performance nickel-based nanocomposite anode for solid oxide fuel cells suitable for mass production. A co-precipitation method is used to achieve uniform mixing of NiO and rare-earth-doped cerium oxide at the nanoscale, enhancing the interfacial interaction between the two phases and obtaining a uniform nanoscale composite powder, effectively expanding the three-phase reaction zone area of ​​the anode. During the anode construction process, this nanocomposite powder can be directly applied to the solid oxide battery without a sintering step, maximizing the preservation of the nanostructure integrity of the composite anode. Compared with electrodes prepared by mechanical mixing, sol-gel methods, and sintered electrodes, this method significantly improves the output performance and long-term operational stability of the single cell.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a high-performance, mass-producible nickel-based nanocomposite anode for solid oxide fuel cells. The composite anode is composed of NiO and rare-earth-doped cerium oxide, with the rare-earth elements selected from one or more of Gd, Sm, Y, La, Pr, and Nd. The method includes the following steps: (1) Dissolve the soluble salts of the required Ni, Ce and rare earth metal elements in deionized water to prepare a mixed salt solution. Add the precipitant dropwise to the mixed salt solution under continuous stirring until complete precipitation. After washing and drying, the precipitate is heat-treated to obtain nanocomposite powder. (2) Grind the nanocomposite powder obtained in step (1) with the binder until uniform to obtain the anode slurry; (3) The anode slurry obtained in step (2) is coated on the electrolyte surface and heat-treated to obtain a nanocomposite anode.

[0005] Furthermore, in the preparation method, the doping amount of rare earth elements in rare earth-doped cerium oxide is 1 mol% to 40 mol%; and in the composite anode, NiO accounts for 40% to 90% of the total mass.

[0006] Furthermore, the total concentration of metal ions in the mixed salt solution in step (1) is 0.1~2 mol / L.

[0007] Furthermore, the stirring rate in step (1) is 400~800 rpm.

[0008] Furthermore, the precipitant used in step (1) is sodium hydroxide, and the concentration of the precipitant solution is 0.5~2 mol / L.

[0009] Furthermore, the drying temperature in step (1) is 80~120 °C and the drying time is 10~15 hours.

[0010] Furthermore, in step (1), the heat treatment temperature is 700~900 °C and the heat treatment time is 2~5 hours.

[0011] Furthermore, the mass ratio of the nanocomposite powder to the binder in step (2) is 7:3; the binder used is a mixture of terpineol and ethyl cellulose, with ethyl cellulose accounting for 2% to 10% of the total mass of the binder.

[0012] Furthermore, the electrolyte sheet in step (3) is made of (Sc2O3). 0.1 (CeO2) 0.01 (ZrO2) 0.89 .

[0013] Furthermore, the heat treatment temperature in step (3) is 80~180°C and the time is 1~2 hours.

[0014] Furthermore, during the anode construction process, this nanocomposite powder can be directly applied to solid oxide batteries without a sintering step.

[0015] The beneficial effects of this invention are as follows: 1. This invention achieves spontaneous ordered composite formation of NiO and rare earth-doped cerium oxide through co-precipitation, constructing a strong interfacial interaction between the two phases. This not only enables the batch preparation of nanoscale powders but also greatly improves the structural stability of the nanopowders.

[0016] 2. In the process of constructing the nickel-based nanocomposite powder prepared by this invention as the anode of a solid oxide fuel cell, the original fine structure of the composite powder is retained, and it has a rich anode three-phase reaction zone area. Compared with mechanical mixing, sol-gel preparation and sintered electrode, it significantly improves the output performance and operating stability of the single cell.

[0017] 3. The nickel-based nanocomposite anode preparation method proposed in this invention has significant advantages such as low equipment requirements, wide availability of raw materials, simple and stable process, low production cost, and suitability for large-scale production, and has good prospects for industrial application. Attached Figure Description

[0018] Figure 1 The images show the XRD patterns of the NiO-GDC (7:3) nanocomposite anode powder prepared in Example 1, the NiO-GDC composite anode powder prepared by mechanical mixing in Comparative Example 1, and the NiO-GDC composite anode powder prepared by sol-gel in Comparative Example 2.

[0019] Figure 2SEM images of the NiO-GDC (7:3) nanocomposite anode powder prepared in Example 1, the NiO-GDC composite anode powder prepared by mechanical mixing in Comparative Example 1, and the NiO-GDC composite anode powder prepared by sol-gel in Comparative Example 2.

[0020] Figure 3 The image shows the HAADF image and elemental distribution of the NiO-GDC (7:3) nanocomposite anode material prepared in Example 1.

[0021] Figure 4 The graph shows a comparison of the power density curves of solid oxide fuel cells in Application Example 1, Application Comparative Example 1, Application Comparative Example 2, and Application Comparative Example 3.

[0022] Figure 5 This is a comparison chart of the stability curves of solid oxide fuel cells in Application Example 1, Application Comparative Example 1, Application Comparative Example 2, and Application Comparative Example 3. Detailed Implementation

[0023] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0024] Example 1: NiO-GDC (7:3) The composite anode is composed of NiO and gadolinium oxide-doped cerium oxide (GDC) material, wherein the gadolinium doping content in GDC is 10 mol%, and NiO accounts for 70% of the total mass of the anode material.

[0025] Weigh 4.55 g of Ni(NO3)2·6H2O, 1.13 g of Ce(NO3)3·6H2O, and 0.13 g of Gd(NO3)3·6H2O into a beaker, add 400 ml of deionized water, and add 1 mol / L NaOH solution dropwise while stirring at 600 rpm. Continue stirring until no more precipitate is formed in the solution. Filter and wash the precipitate several times, and dry it in an oven at 80 °C for 12 hours. Transfer the obtained precursor to a muffle furnace and heat treat it at 800 °C for 2 hours to obtain NiO-GDC (7:3) powder.

[0026] Example 2 NiO-GDC (6:4) The composite anode is composed of NiO and GDC materials, wherein the gadolinium doping content in GDC is 10 mol%, and NiO accounts for 60% of the total mass of the anode material.

[0027] Weigh 4.06 g of Ni(NO3)2·6H2O, 1.57 g of Ce(NO3)3·6H2O, and 0.18 g of Gd(NO3)3·6H2O into a beaker, add 400 ml of deionized water, and add 1 mol / L NaOH solution dropwise while stirring at 600 rpm. Continue stirring until no more precipitate is formed in the solution. Filter and wash the precipitate several times, and dry it in an oven at 80 °C for 12 hours. Transfer the obtained precursor to a muffle furnace and heat treat it at 800 °C for 2 hours to obtain NiO-GDC (6:4) powder.

[0028] Comparative Example 1: Mechanically Mixed NiO-GDC (7:3) The composite anode is composed of NiO and GDC materials, wherein the gadolinium doping content in GDC is 10 mol%, and NiO accounts for 70% of the total mass of the anode material.

[0029] (1) Weigh 5.82 g of Ni(NO3)2·6H2O into a beaker, add 400 ml of deionized water, and add 1 mol / L NaOH solution dropwise at a stirring rate of 600 rpm. Continue stirring until no more precipitate is produced in the solution. Filter and wash the precipitate several times, put it in an oven and dry it at 80 °C for 12 hours. Transfer the obtained precursor to a muffle furnace and heat treat it at 800 °C for 2 hours to obtain NiO powder. (2) Weigh 5.21 g of Ce(NO3)3·6H2O and 0.60 g of Gd(NO3)3·6H2O into a beaker, add 400 ml of deionized water, and add 1 mol / L NaOH solution dropwise while stirring at 600 rpm. Continue stirring until no more precipitate is produced in the solution. Filter and wash the precipitate several times, put it in an oven and dry it at 80 °C for 12 hours. Transfer the obtained precursor to a muffle furnace and heat treat it at 800 °C for 2 hours to obtain GDC powder. (3) Weigh NiO and GDC in a mortar at a mass ratio of 7:3 and grind them evenly to obtain mechanically mixed NiO-GDC (7:3) powder.

[0030] Comparative Example 2: Sol-gel NiO-GDC (7:3) The composite anode is composed of NiO and GDC materials, wherein the gadolinium doping content in GDC is 10 mol%, and NiO accounts for 70% of the total mass of the anode material.

[0031] Weigh 27.25 g of Ni(NO3)2·6H2O, 0.78 g of Gd(NO3)3·6H2O, 6.78 g of Ce(NO3)3·6H2O, 32.00 g of citric acid, and 32.46 g of ethylenediaminetetraacetic acid into a beaker, pour in 100 mL of deionized water, and slowly pour in 66.63 mL of a 30wt% ammonia solution. Stir continuously at room temperature until the solution becomes clear. Stir continuously at 300°C until the solution forms a gel, and then place it in an oven to dry all the moisture. Transfer the obtained precursor to a muffle furnace and heat treat it at 1000°C for 3 hours to obtain NiO-GDC (7:3) sol-gel powder.

[0032] Application Example 1 Weigh 0.7 g of the composite anode powder prepared by coprecipitation in Example 1 into a mortar, add 0.3 g of binder (formed by uniformly mixing 48 g of terpineol and 2 g of ethyl cellulose), and grind evenly to obtain an anode slurry. Coat the prepared anode slurry evenly on (Sc2O3). 0.1 (CeO2) 0.01 (ZrO2) 0.89 An electrolyte-supported half-cell was fabricated using NiO-GDC (7:3) anode material on a (ScSZ) electrolyte sheet (ScSZ thickness 350 µm). Then, La... 0.6 Sr 0.4 Co 0.2 Fe 0.8 An O3 (LSCF) cathode was coated on the ScSZ electrolyte containing a GDC separator layer (1 µm thick) on the other side, and a full cell was obtained after heat treatment at 150 °C for 2 h.

[0033] Application Comparative Example 1 Weigh 0.7 g of the anode powder prepared by mechanical mixing in Comparative Example 1 into a mortar, add 0.3 g of binder (formed by uniformly mixing 48 g of terpineol and 2 g of ethyl cellulose), and grind evenly to obtain an anode slurry. Coat the prepared anode slurry evenly onto the ScSZ electrolyte sheet (the thickness of ScSZ is 350 µm) to obtain an electrolyte-supported half cell prepared by mechanically mixed NiO-GDC (7:3) anode material. Then coat the LSCF cathode onto the ScSZ electrolyte with a GDC separator layer on the other side (the thickness of the GDC separator layer is 1 µm). After heat treatment at 150 °C for 2 h, a full cell is obtained.

[0034] Application Comparative Example 2 Weigh 0.7 g of the anode powder prepared by the sol-gel in Comparative Example 2 into a mortar, add 0.3 g of binder (formed by uniformly mixing 48 g of terpineol and 2 g of ethyl cellulose), and grind evenly to obtain an anode slurry. Coat the prepared anode slurry evenly onto the ScSZ electrolyte sheet (the thickness of ScSZ is 350 µm) to obtain an electrolyte-supported half cell prepared by the NiO-GDC (7:3) anode material of sol-gel. Then coat the LSCF cathode onto the ScSZ electrolyte with a GDC separator layer on the other side (the thickness of the GDC separator layer is 1 µm). After heat treatment at 150 °C for 2 h, a full cell is obtained.

[0035] Application Comparative Example 3 Weigh 0.7 g of the composite anode powder obtained by co-precipitation in Example 1 into a mortar, add 0.3 g of binder (formed by uniformly mixing 48 g of terpineol and 2 g of ethyl cellulose), and grind evenly to obtain an anode slurry. The prepared anode slurry is uniformly coated on the ScSZ electrolyte sheet (the thickness of ScSZ is 350 µm), and then placed in a tube furnace and heated to 950 °C for 3 h for heat treatment to obtain an electrolyte-supported half cell prepared from sintered NiO-GDC (7:3) anode material. Then, the LSCF cathode is coated on the other side of the ScSZ electrolyte containing the GDC isolation layer (the thickness of the GDC isolation layer is 1 µm), and after heat treatment at 150 °C for 2 h, a full cell is obtained.

[0036] Figure 1 The XRD patterns of NiO-GDC (7:3) powders from Example 1, Comparative Example 1 NiO-GDC (7:3), and Comparative Example 2 NiO-GDC (7:3) are shown. Analysis results indicate that the diffraction peaks of all three powders precisely match the standard characteristic peaks of the NiO and GDC phases, and no obvious impurity phase diffraction peaks were detected in the spectra. This result not only confirms the successful preparation of the NiO-GDC nanocomposite anode material but also demonstrates that no adverse chemical reactions occurred between NiO and GDC at the target component ratio (7:3), indicating excellent chemical compatibility between the two.

[0037] Figure 2 The images show SEM characterization images of NiO-GDC (7:3) from Example 1, Comparative Example 1 NiO-GDC (7:3), and Comparative Example 2 NiO-GDC (7:3). As can be seen from the figures, the nickel-based nanocomposite anode material prepared by this method has a more uniform particle size distribution and a significantly reduced size, effectively expanding the three-phase reaction zone area of ​​the anode.

[0038] Figure 3The image shows the HAADF image and elemental distribution of NiO-GDC (7:3) from Example 1. As can be seen from the image, uniformly mixed nanoparticles were prepared, with GDC particles coating the Ni surface, enhancing the interfacial interaction between the two and effectively suppressing the growth and coarsening of the Ni nanoparticles.

[0039] Figure 4 This is a comparison graph showing the power density curves of solid oxide fuel cells used in Application Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. A single cell using the co-precipitated NiO-GDC nanocomposite anode material as the anode can achieve a power density of 0.70 W·cm⁻¹ at 800°C in a hydrogen atmosphere. -2 The peak power density is 37% higher than that of a single cell using NiO-GDC nanocomposite anode material prepared by mechanical mixing, 67% higher than that of a single cell using NiO-GDC nanocomposite anode material prepared by sol-gel, and 63% higher than that of a single cell using sintered electrode, demonstrating that the NiO-GDC nanocomposite anode prepared in this invention has good catalytic activity.

[0040] Figure 5 This is a comparison graph showing the stability curves of solid oxide fuel cells used in Application Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. A single cell was subjected to an application temperature of 800 °C and a hydrogen atmosphere at 250 mA·cm⁻¹. -2 The current polarization was carried out for 100 h. As can be seen from the figure, the decay rate of the solid oxide fuel cell in Application Example 1 was 0.01% / h after 100 h, while the decay rates of the solid oxide fuel cells prepared in Comparative Example 1 and Comparative Example 3 were 0.02% / h and 0.03% / h, respectively. In comparison, the solid oxide fuel cell in Application Example 1 has excellent long-term operating stability, indicating that the NiO-GDC nanocomposite powder prepared in this invention has excellent structural stability.

[0041] Table 1 Comparison of anode powder particle size, battery performance, and degradation rate in various application examples

[0042] Table 1 compares the anode powder particle size, battery performance, and degradation rate in each application example. The powder used in Application Example 1 has a finer and more uniformly distributed particle size, exhibiting higher peak power density and better stability in a solid oxide fuel cell. These results demonstrate that the preparation method proposed in this invention significantly improves the electrochemical performance of the electrode while also considering process efficiency and structural stability, thus verifying its comprehensive technical advantages of combining high performance with suitability for mass production.

[0043] The specific embodiments described above 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 claims of this invention should be considered within the scope of this invention.

Claims

1. A method for preparing a high-performance nickel-based nanocomposite anode material suitable for mass production of solid oxide fuel cells, wherein the composite anode is composed of NiO and rare-earth-doped cerium oxide, and the rare-earth elements are selected from one or more of Gd, Sm, Y, La, Pr, and Nd, characterized in that... The preparation method includes the following steps: (1) Dissolve the required Ni, Ce and rare earth element soluble salts in deionized water to prepare a mixed salt solution. Add the precipitant dropwise to the mixed salt solution under continuous stirring until complete precipitation. After washing and drying, the precipitate is heat-treated to obtain nanocomposite powder. (2) Grind the nanocomposite powder obtained in step (1) with the binder until uniform to obtain the anode slurry; (3) The anode slurry obtained in step (2) is coated on the electrolyte surface and heat-treated to obtain a nanocomposite anode.

2. The preparation method according to claim 1, characterized in that: In rare earth-doped cerium oxide, the doping amount of rare earth elements is 1 mol% to 40 mol%; in composite anodes, NiO accounts for 40% to 90% of the total mass.

3. The preparation method according to claim 1, characterized in that: The total concentration of metal ions in the mixed salt solution described in step (1) is 0.1~2 mol / L.

4. The preparation method according to claim 1, characterized in that: The stirring speed in step (1) is 400~800 rpm.

5. The preparation method according to claim 1, characterized in that: The precipitant mentioned in step (1) is a sodium hydroxide solution with a concentration of 0.5~2 mol / L.

6. The preparation method according to claim 1, characterized in that: The drying temperature in step (1) is 80~120°C and the time is 10~15 hours.

7. The preparation method according to claim 1, characterized in that: The heat treatment in step (1) is performed at a temperature of 700~900 °C for 2~5 hours.

8. The preparation method according to claim 1, characterized in that: The adhesive described in step (2) consists of terpineol and ethyl cellulose, with ethyl cellulose accounting for 2% to 10% of the total mass of the adhesive.

9. The preparation method according to claim 1, characterized in that: The electrolyte sheet in step (3) is made of (Sc2O3). 0.1 (CeO2) 0.01 (ZrO2) 0.89 .

10. The preparation method according to claim 1, characterized in that: The heat treatment temperature in step (3) is 80~180°C and the time is 1~2 hours.

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