A method for preparing high-dispersion nickel-silica particles on a ysz surface

Abstract

The application discloses a method for preparing high-dispersed nickel-silicon oxide particles on the surface of YSZ particles, and the method comprises the following steps: loading nickel oxide on the surface of YSZ (Ni / YSZ) by using an impregnation method, and coating a uniform and dense amorphous SiO2 film on the surface of the Ni / YSZ particles by using a chemical vapor deposition method; the film is in close contact with the nickel oxide, and after high-temperature calcination at 1400 DEG C, the film becomes spherical small particles and is uniformly dispersed on the YSZ framework. The uniformly distributed nickel-silicon oxide particles on the surface of YSZ prepared by the method can effectively inhibit the agglomeration of Ni in the water and heat cycle of the battery, and can significantly improve the current density.

Description

Technical Field

[0001] This invention relates to the field of energy materials and discloses a method for depositing highly dispersed nickel-silicon oxide particles on the surface of YSZ particles. Background Technology

[0002] Solid oxide fuel cells (SOFCs), as an all-solid-state energy conversion device, can achieve continuous and efficient energy output using clean energy. One of the most prominent advantages of SOFCs is their strong fuel adaptability; various hydrocarbons besides hydrogen can be used as fuels. The performance of SOFC cells is closely related to the microstructure of the anode material. The following electrochemical reaction typically occurs at the anode side of an SOFC: after the fuel gas diffuses to the anode, it undergoes an electrochemical oxidation reaction with oxygen ions transported by the electrolyte. The generated electrons and products need to be promptly transported out of the anode. Therefore, the reactive region is a multiphase interface, the so-called three-phase interface (TPB), which is generally defined as the convergence point of the oxygen ion conductor (electrolyte), the electronically conductive metal phase, and the gas phase. Therefore, the anode material needs to have good catalytic oxidation activity for the fuel gas, as well as good electronic conductivity, enabling rapid charge exchange during the reaction. To allow the fuel gas to diffuse smoothly to the electrode to participate in the reaction and remove the generated water, the anode material must also have a porous structure. In addition, the anode material must be heat-resistant, able to withstand thermal cycling from room temperature to high temperature, and have suitable mechanical, thermal properties and chemical compatibility to match other components of SOFC batteries.

[0003] Considering both cost and performance, Ni-YSZ cermet is currently the most commonly used material for anodes. YSZ not only acts as a support to limit the growth and agglomeration of Ni metal grains, maintaining Ni dispersion and anode porosity, but also provides oxygen ion conductivity, expanding the electrochemical reaction active region of the anode. However, cermets still cannot meet all the requirements of an ideal anode. After prolonged high-temperature hydrothermal cycling, Ni particles will severely agglomerate, reducing the three-phase reaction interface and significantly affecting the anode's power density. When hydrocarbons are used as fuel, they will pyrolyze on the surface to form a dense carbon layer, hindering the contact between fuel gas and anode, compromising anode porosity, and ultimately affecting battery performance.

[0004] Many research groups have improved the structure of Ni-YSZ cermets through various methods to enhance their adaptability to fuel gas and improve their performance during long-term high-temperature hydrothermal cycling. Currently, commonly used methods include direct impregnation, hydrothermal methods, co-precipitation, and in-situ dissolution techniques. Jiang et al. used ion impregnation to impregnate a Ni / YSZ electrode with YSZ and SDC. Under a humid hydrogen atmosphere at 800℃, the interfacial resistance (RE) decreased to 1.62 Ω·cm after YSZ impregnation. 2After impregnation with SDC, RE further decreased to 0.76 Ω·cm. 2 After further increasing the impregnation amount of SDC, RE was only 0.24 Ω·cm. 2 Yao Xueli successfully synthesized HT-NiO-SDC composite anode material for the first time using a one-step hydrothermal method. Using HT-70 mol.% NiO-30 mol.% SDC as the anode material, a single cell supported by the composite electrolyte achieved maximum power densities of 738 mW / cm³ at 700℃ with hydrogen and methanol as fuels, respectively. 2 and 600mW / cm 2 Myung et al. achieved in-situ dissolution of Ni particles on LCNTs via electrochemical polarization. This electrode structure achieved a current density of 2 W / cm² in humidified hydrogen gas at 900 °C. 2 Furthermore, during the 150-hour test, the nanostructure and corresponding electrochemical activity of the Ni particles did not decrease.

[0005] Literature studies show a strong interaction between Si and Ni. Si and Zr can form ZrSiO4 at high temperatures, while layered silicates can anchor Ni particles, giving Ni anti-sintering properties at high temperatures. Most liquid-phase preparation techniques cannot precisely control the size and uniformity of each dopant element, and the processes are cumbersome and prone to introducing impurities. Therefore, we propose a low-temperature chemical vapor deposition technique for amorphous SiO2 on the surface of Ni / YSZ particles. Using SiCl4 as a Si precursor, it reacts with the hydroxyl groups of nickel oxide on the surface of YSZ particles at room temperature to form a uniform amorphous SiO2 film. After calcination at 1400℃, this SiO2 film, along with nickel oxide, becomes spherical particles uniformly dispersed on the YSZ framework, effectively suppressing Ni agglomeration during battery hydrothermal cycling and simultaneously increasing current density. Summary of the Invention

[0006] This invention discloses a method for depositing a highly dispersed nickel-silicon oxide composite on the surface of YSZ particles. This method effectively improves the uniform dispersion of Ni particles on the YSZ surface and suppresses their agglomeration under high-temperature circulating hydrothermal conditions. The main technical solution employed in this invention involves loading nickel oxide onto the surface of YSZ particles, using easily volatile and hydrolyzable SiCl4 as a precursor, and employing chemical vapor deposition to react with the surface hydroxyl groups of the Ni / YSZ particles at low temperature to form a silicon chloride film. After hydrolysis and drying, a uniform and dense amorphous SiO2 film is generated on the surface of the Ni / YSZ particles. This film is in close contact with the nickel oxide components on the YSZ surface. Calcination at 1400℃ yields a uniformly dispersed silicon-silicon oxide composite on the Ni / YSZ particle surface. This composite is then reduced to highly dispersed elemental Ni particles during SOFC use, improving battery stability and discharge performance.

[0007] This invention is achieved through the following technical means:

[0008] This invention discloses a method for depositing a highly dispersed nickel-silica composite on the surface of YSZ particles, comprising:

[0009] Impregnation treatment;

[0010] Chemical vapor deposition; and

[0011] Calcination treatment.

[0012] Specifically, it includes:

[0013] (1) Ni impregnation on YSZ surface:

[0014] Commercially available YSZ particles were used, with nickel nitrate hexahydrate as the nickel source. Nickel was loaded onto the YSZ surface using an equal-volume impregnation method at a Ni:YSZ mass ratio of 0.01–0.1, with an impregnation time of 12–24 hours. After impregnation, vacuum drying was performed at a vacuum level of not less than 0.08 MPa, a drying temperature of not less than 60°C, and a drying time of not less than 6 hours.

[0015] (2) Synthesis of Ni / YSZ particles:

[0016] The dried nickel nitrate-impregnated YSZ is calcined at a temperature of 200–300°C for a time of not less than 4 hours.

[0017] (3) Drying treatment of Ni / YSZ:

[0018] The prepared Ni / YSZ particles were dried at 120℃ for 2 hours to further remove adsorbed water from the surface of the Ni / YSZ particles.

[0019] (4) Preparations before sedimentation:

[0020] The dried Ni / YSZ particles are uniformly dispersed in a sealed container, with a particle sample thickness not exceeding 2 mm. The sealed container has a liquid sample injection port, a vacuum interface, a heating function, and a sealing gasket. A certain amount of SiCl4 is injected into the sample vial of the sealed container through the sample injection port, and a vacuum is applied. The mass ratio of SiCl4 to Ni / YSZ is 0.01–0.1, and the vacuum level is not lower than 0.08 MPa.

[0021] (5) Vapor deposition:

[0022] After completely sealing the container, maintain a constant temperature of 50–70°C for 10–30 minutes during the reaction. Afterward, further evacuate the container to a vacuum level of at least 0.08 MPa, and remove the SiCl4 from the discharged gas using NaOH solution.

[0023] (6) Surface hydrolysis:

[0024] Air is introduced into a sealed container to atmospheric pressure, with a humidity of 30%–70%. A hydrolysis reaction is carried out using water vapor for 30–60 minutes. After the reaction, the Ni / YSZ particles are removed and dried in an oven at 105°C for 2 hours to obtain SiO2-coated Ni / YSZ particles.

[0025] (7) Calcination:

[0026] The obtained SiO2-coated Ni / YSZ particles were calcined at 1400℃ to obtain highly dispersed nickel-silicon oxide particles.

[0027] The present invention also discloses a highly dispersed nickel-silicon oxide particle prepared according to the above deposition method.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention avoids liquid-phase reactions, is simple to operate, and generates no waste liquid. It can coat Ni / YSZ particles with a uniform and dense amorphous SiO2 film at room temperature. Calcination of nickel oxide and the SiO2 film at high temperature yields highly dispersed nickel-silicon oxide particles. The calcination process is consistent with the battery forming process, allowing for direct one-step acquisition of highly dispersed particles during battery fabrication. This effectively enhances the uniform dispersion of Ni particles on the YSZ framework and improves the agglomeration of Ni particles during high-temperature hydrothermal cycling. Attached Figure Description

[0030] Figure 1 a is a SEM image of Ni / YSZ coated with calcined silicon dioxide obtained according to the method in Example 1.

[0031] Figure 1 b is an SEM image of untreated Ni / YSZ particles after calcination. Detailed Implementation

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

[0033] Example 1

[0034] a. Using commercially available YSZ particles and nickel nitrate hexahydrate as the nickel source, nickel was loaded onto the YSZ surface using an equal-volume impregnation method at a Ni:YSZ mass ratio of 0.05 for 18 hours. After impregnation, vacuum drying was performed at a vacuum degree of 0.08 MPa, a drying temperature of 60°C, and a drying time of 6 hours. The dried nickel nitrate-impregnated YSZ was then calcined at 250°C for 4 hours, followed by drying at 120°C for 2 hours to remove adsorbed water from the surface of the Ni / YSZ particles.

[0035] b. Take the dried Ni / YSZ particles and disperse them evenly in a sealed container. The particle sample should be spread to a thickness of 2 mm.

[0036] c. Take a certain amount of SiCl4 and put it into the sample bottle of the sealed container through the sample injection port. The mass ratio of SiCl4 to Ni / YSZ is 0.05. Then, evacuate the vacuum to a vacuum degree of 0.08 MPa.

[0037] d. After completely sealing the container, maintain a constant temperature of 60℃ for 20 minutes. After the reaction, further evacuate the container to a vacuum level of 0.08 MPa.

[0038] e. Pour air with a humidity of 50% into a sealed container until atmospheric pressure is reached, and allow the hydrolysis reaction time to be 40 minutes. After the reaction is complete, remove the Ni / YSZ particles and dry them in an oven at 105°C for 2 hours to obtain SiO2-coated Ni / YSZ particles.

[0039] f. The obtained SiO2-coated Ni / YSZ particles were calcined at 1400℃ to obtain a highly dispersed nickel-silicon oxide composite.

[0040] The SEM image of the sample obtained in Example 1 is shown below. Figure 1 As shown in Figure a, SiCl4 coating can form uniformly distributed, nanoscale spherical nickel-silicon oxide particles on the YSZ surface. (SEM image of uncoated Ni / YSZ powder after calcination is shown in Figure a.) Figure 1 As shown in b, without silicon oxide coating, highly dispersed components cannot be formed. SiO2-coated Ni / YSZ particles obtained in Example 1 and untreated Ni / YSZ particles were used. SDC cathode and the aforementioned prepared anode powder were coated onto both sides of the electrolyte sheet using screen printing technology, and then calcined at 1400℃. Discharge performance was tested using a Blue Electric electrochemical workstation. Moistened hydrogen gas was introduced into the anode terminal of the battery, while the cathode was exposed to air. The current intensity at the anode was measured at 700℃ and 750℃ using a constant voltage test mode, and the average power density on the anode side of the single cell was calculated accordingly. The test results are shown in Table 1.

[0041] Table 1. Test data of anode powder performance

[0042]

[0043] As shown in the figures and tables, the nickel-silicon oxide composite obtained after SiO2 coating and high-temperature calcination can effectively suppress the aggregation of Ni on the YSZ framework, improve the dispersibility of Ni, and increase the power density of the battery.

[0044] Example 2

[0045] a. Using commercially available YSZ particles and nickel nitrate hexahydrate as the nickel source, nickel was loaded onto the YSZ surface using an equal-volume impregnation method at a Ni:YSZ mass ratio of 0.01 for 12 hours. After impregnation, vacuum drying was performed at a vacuum degree of 0.08 MPa, a drying temperature of 60°C, and a drying time of 6 hours. The dried nickel nitrate-impregnated YSZ was then calcined at 200°C for 4 hours, followed by drying at 120°C for 2 hours to remove adsorbed water from the surface of the Ni / YSZ particles.

[0046] b. Take the dried Ni / YSZ particles and disperse them evenly in a sealed container. The particle sample should be spread to a thickness of 2 mm.

[0047] c. Take a certain amount of SiCl4 and put it into the sample bottle of the sealed container through the sample injection port. The mass ratio of SiCl4 to Ni / YSZ is 0.01. Then, evacuate the vacuum to a vacuum degree of 0.09 MPa.

[0048] d. After completely sealing the container, maintain a constant temperature of 50℃ for 30 minutes. After the reaction, further evacuate the container to a vacuum level of 0.09 MPa.

[0049] e. Pour air with a humidity of 30% into a sealed container until atmospheric pressure is reached, and allow the hydrolysis reaction to proceed for 30 minutes. After the reaction is complete, remove the Ni / YSZ particles and dry them in an oven at 105°C for 2 hours to obtain SiO2-coated Ni / YSZ particles.

[0050] f. The obtained SiO2-coated Ni / YSZ particles were calcined at 1400℃ to obtain a highly dispersed nickel-silicon oxide composite.

[0051] Example 3

[0052] a. Using commercially available YSZ particles and nickel nitrate hexahydrate as the nickel source, nickel was loaded onto the YSZ surface using an equal-volume impregnation method at a Ni:YSZ mass ratio of 0.1 for 24 hours. After impregnation, vacuum drying was performed at a vacuum degree of 0.08 MPa, a drying temperature of 60℃, and a drying time of 6 hours. The dried nickel nitrate-impregnated YSZ was then calcined at 300℃ for 4 hours, followed by drying at 120℃ for 2 hours to remove adsorbed water from the surface of the Ni / YSZ particles.

[0053] b. Take the dried Ni / YSZ particles and disperse them evenly in a sealed container. The particle sample should be spread to a thickness of 2 mm.

[0054] c. Take a certain amount of SiCl4 and put it into the sample bottle of the sealed container through the sample injection port. The mass ratio of SiCl4 to Ni / YSZ is 0.1. Then, evacuate the vacuum to a vacuum degree of 0.09 MPa.

[0055] d. After completely sealing the container, maintain a constant temperature of 70℃ for 10 minutes. After the reaction, further evacuate the container to a vacuum level of 0.09 MPa.

[0056] e. Introduce air with a humidity of 70% into a sealed container until atmospheric pressure is reached, and allow the hydrolysis reaction to proceed for 60 minutes. After the reaction is complete, remove the Ni / YSZ particles and dry them in an oven at 105°C for 2 hours to obtain SiO2-coated Ni / YSZ particles.

[0057] f. The obtained SiO2-coated Ni / YSZ particles were calcined at 1400℃ to obtain a highly dispersed nickel-silicon oxide composite.

[0058] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for depositing highly dispersed nickel-silicon oxide particles on the surface of YSZ particles, comprising: (1) preparing Ni / YSZ particles: loading nickel on the surface of YSZ by using equal volume impregnation method, after impregnation, vacuum drying, calcination and drying treatment are carried out, and dry Ni / YSZ particles are obtained for standby; (2) preparation before deposition: taking the dry Ni / YSZ particles and uniformly dispersing them in a sealed container, the sample is spread to a thickness of not more than 2 mm, SiCl4 is taken and injected into the sample bottle of the sealed container, and vacuum is extracted, and the preparation before deposition is completed; (3) vapor deposition: after the sealed container is completely sealed, constant temperature reaction of the sealed container is controlled, after the reaction is completed, the sealed container is further vacuumed, and the discharged gas is removed by NaOH solution to remove SiCl4; (4) hydrolysis and calcination: air is introduced into the sealed container to normal pressure, and hydrolysis reaction is carried out by using water vapor, after the reaction is completed, the Ni / YSZ particles are taken out, dried and calcined, and highly dispersed nickel-silicon oxide particles are obtained.

2. The method according to claim 1, wherein: in step (1), the nickel source used in the equal volume impregnation method is nickel nitrate hexahydrate; the mass ratio of Ni to YSZ is 0.01-0.1:1; the impregnation time is 12-24 h.

3. The method according to claim 1, wherein: in step (1), the vacuum drying has a vacuum degree of not less than 0.08 MPa, a temperature of not less than 60℃ and a time of not less than 6 h.

4. The method according to claim 1, wherein: in step (1), the calcination temperature is 200-300℃, and the calcination time is not less than 4 h.

5. The method according to claim 1, wherein: in step (1), the drying temperature is 120℃, and the drying time is 2 h.

6. The method according to claim 1, wherein: in step (2), the sealed container has a liquid sample injection port, a vacuum extraction interface, a heating function and a sealing gasket; the mass ratio of SiCl4 to Ni / YSZ is 0.01-0.1:1; the vacuum degree is not less than 0.08 MPa.

7. The method according to claim 1, wherein: in step (3), the constant temperature reaction temperature of the sealed container is 50-70℃, and the reaction time is 10-30 min; the vacuum degree is not less than 0.08 MPa.

8. The method according to claim 1, wherein: in step (4), the air humidity is 30%-70%; the hydrolysis reaction time is 30-60 min; the drying temperature is 105℃, and the drying time is 2 h.

9. The method according to claim 1, wherein: in step (4), the calcination temperature is 1400℃.

10. Highly dispersed nickel-silicon oxide particles prepared by the method according to any one of claims 1-9.

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