NiO@YSZ core-shell nanosphere-based soec hydrogen electrode functional layer and preparation method thereof

Abstract

The application provides a kind of NiO@YSZ nanocomposite material, including YSZ core and the shell of NiO coated on YSZ core;NiO@YSZ nanocomposite material is spherical particle with core-shell structure;NiO shell has the surface morphology of wrinkle.The nanocomposite particle provided by the application is mainly NiO microcrystal in shell layer, and YSZ microcrystal in core, forming three-dimensional interconnected structure of electronic conductor-ion conductor.The cathode functional layer is made of it, and is accurately located between cathode base and electrolyte, to maximize the active area of three-phase interface.NiO@YSZ core-shell structure nanoparticles prepared by ultrasonic spray pyrolysis process of the application are applied to SOEC hydrogen electrode functional layer, which can significantly reduce polarization resistance, improve water electrolysis hydrogen efficiency and long-term stability of device, and the process is scalable, with high degree of continuous spray pyrolysis, high utilization rate of precursor, no secondary pollution, and can realize batch production of particles.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide electrolysis water electrolysis hydrogen production technology, and relates to a NiO@YSZ nanocomposite material and its preparation method and apparatus, a solid oxide electrolysis cell, and particularly to a functional layer of SOEC hydrogen electrode based on NiO@YSZ core-shell nanospheres and its preparation method. Background Technology

[0002] Solid oxide electrolyzers (SOECs), as the core device of high-temperature water electrolysis for hydrogen production, have become a key technological path for achieving large-scale green hydrogen production under the "dual carbon" goal due to their advantages such as high energy conversion efficiency, high purity of green hydrogen, and utilization of industrial high-temperature waste heat. The electrolysis performance and long-term stability of SOECs depend primarily on the structure and performance of the hydrogen electrode materials—the cathode must simultaneously possess excellent electronic conductivity, oxygen ion conductivity, water splitting catalytic activity, and structural stability at high temperatures, and all four properties are closely related to the microstructure of the electrode materials.

[0003] The NiO@YSZ composite system has become the mainstream material for SOEC hydrogen electrodes due to the high electronic conductivity and water splitting catalytic activity of Ni, and the high oxygen ion conductivity and chemical stability of YSZ. However, traditional methods for preparing NiO@YSZ particles (such as mechanical mixing and sol-gel methods) have insurmountable drawbacks: mechanical mixing can only achieve macroscopic mixing of NiO and YSZ particles, resulting in uneven microcrystalline dispersion and a wide particle size distribution, leading to a limited three-phase interface (TPB) area and high polarization resistance. In the solid state, the diffusion rate of atoms or ions is relatively slow, making it difficult to achieve uniform mixing of raw materials at the microscopic level using only mechanical mixing. This can lead to incomplete reactions or the formation of impurity phases in localized areas during subsequent high-temperature solid-state reactions due to variations in raw material ratios, ultimately affecting the purity and performance uniformity of the ceramic oxide powder. Furthermore, higher sintering temperatures (typically 800-1200℃) are required to ensure sufficient chemical reactions between solid materials, undoubtedly increasing energy consumption during production. Simultaneously, under high-temperature reaction conditions, grains tend to grow, resulting in larger particle sizes of the obtained ceramic oxide powder, which is unfavorable for applications requiring precise particle size control. Large particle sizes may affect the material's density and electrical properties. While the sol-gel method can improve dispersibility to some extent, its preparation process is complex, reaction conditions are sensitive, agglomeration is prone to occur, and precise control of particle morphology and internal structure is difficult. These defects directly result in high SOEC electrolysis voltage and significant energy loss. Additionally, under high-temperature electrolysis conditions (600-800℃), traditional NiO@YSZ electrodes are prone to Ni particle agglomeration and TPB region shrinkage, severely impacting the long-term operational stability of SOEC and hindering its industrial application.

[0004] Therefore, finding a more suitable method for preparing NiO@YSZ particles and solving the aforementioned technical problems in the preparation of existing NiO@YSZ particles has become a focus of attention for many forward-thinking researchers in the industry. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a NiO@YSZ nanocomposite material and its preparation method, preparation device, and a solid oxide electrolyzer, particularly a functional layer for an SOEC hydrogen electrode based on NiO@YSZ core-shell nanospheres. The present invention can controllably prepare NiO@YSZ nanocomposite particles with a core-shell structure, high activity, and high stability. This not only fully leverages the core advantages of spray pyrolysis technology in structural control but also specifically addresses the performance pain points of SOEC hydrogen electrodes, which is of vital significance for improving the efficiency of hydrogen production through water electrolysis, reducing the cost of green hydrogen production, and promoting the industrialization of SOEC. Moreover, the preparation method is simple, highly controllable, and highly stable, making it more suitable for industrial promotion and application.

[0006] This invention provides a NiO@YSZ nanocomposite material, comprising a YSZ core and a NiO shell coating the YSZ core;

[0007] The NiO@YSZ nanocomposite material consists of spherical particles with a core-shell structure.

[0008] The NiO shell has a wrinkled surface morphology.

[0009] Preferably, the NiO@YSZ nanocomposite particles are submicron-sized particles;

[0010] The particle size of the NiO@YSZ nanocomposite material is 360~660 nm;

[0011] The particle size distribution span (SPAN) of the NiO@YSZ nanocomposite material is 0.39~0.46;

[0012] The surface morphology of the folds is specifically a fold morphology formed by the stacking of nanosheets.

[0013] Preferably, the YSZ core includes a YSZ spherical core;

[0014] The YSZ core is specifically a microcrystalline dense core formed by the aggregation of YSZ nanoparticles.

[0015] The NiO shell is a porous shell;

[0016] The thickness of the NiO shell is 30~50 nm.

[0017] Preferably, the mass ratio of NiO to YSZ is (1~2):1;

[0018] The NiO@YSZ nanocomposite material is a NiO@YSZ nanocomposite material synthesized by spray pyrolysis;

[0019] The NiO@YSZ nanocomposite material includes a composite material used for the SOEC hydrogen electrode functional layer;

[0020] The NiO shell is specifically a porous shell formed by stacking NiO nanoparticles.

[0021] This invention provides the application of ultrasonic spray pyrolysis synthesis method in the preparation of NiO@YSZ nanocomposites as described in any of the above technical solutions.

[0022] This invention provides a method for preparing NiO@YSZ nanocomposite materials as described in any of the above technical solutions, comprising the following steps:

[0023] 1) A mixed solution is obtained by mixing nickel nitrate, zirconium oxychloride, yttrium nitrate, and water;

[0024] 2) The mixed solution obtained in the above steps is subjected to ultrasonic spray pyrolysis synthesis. First, the mixed solution is ultrasonically atomized to obtain atomized droplets. Then, under the action of a carrier gas, the atomized droplets are passed through the heating zone for pyrolysis, and the pyrolysis product NiO@YSZ nanocomposite material is collected.

[0025] Preferably, the total concentration of cations in the mixed solution is 0.05~0.5 mol / L;

[0026] In the mixed solution, the mass ratio of NiO and YSZ is (1~2):1;

[0027] The molar content of yttrium oxide in the YSZ is 3YSZ~8YSZ.

[0028] Preferably, the ultrasonic frequency of the ultrasonic atomization is 1~2MHz;

[0029] The carrier gas includes oxygen-containing gas;

[0030] The flow rate of the carrier gas is 1~2L / min;

[0031] The pyrolysis temperature is 600~1000℃;

[0032] The pyrolysis time is 0.5 to 2 seconds.

[0033] This invention provides an apparatus for preparing NiO@YSZ nanocomposite materials as described in any one of the above technical solutions, comprising:

[0034] Ultrasonic atomizing device;

[0035] The precursor solution source is connected to the liquid inlet of the ultrasonic atomizing device;

[0036] A carrier gas source connected to the air inlet of the ultrasonic atomizing device;

[0037] A pyrolysis reaction device connected to the droplet mixture outlet of the ultrasonic atomizing device;

[0038] A product collection device connected to the outlet of the pyrolysis reaction apparatus.

[0039] The present invention also provides a solid oxide electrolytic cell, wherein the solid oxide electrolytic cell comprises the NiO@YSZ nanocomposite material described in any one of the above technical solutions or the NiO@YSZ nanocomposite material prepared by the preparation method described in any one of the above technical solutions.

[0040] This invention provides a NiO@YSZ nanocomposite material, comprising a YSZ core and a NiO shell coating the YSZ core; the NiO@YSZ nanocomposite material consists of spherical particles with a core-shell structure; the NiO shell has a wrinkled surface morphology. Compared with existing technologies, this invention suggests that developing a preparation technology capable of precisely controlling the microstructure of NiO@YSZ composite particles is a core requirement for overcoming the performance bottleneck of SOEC. Ultrasonic spray pyrolysis technology, as a continuous and scalable nanoparticle synthesis method, has the unique advantage of directly controlling the morphology, size, internal structure, and composition distribution of particles from the precursor stage, making it a key technology for overcoming the shortcomings of traditional preparation methods. Compared with other methods, spray pyrolysis technology can achieve the leap from "macroscopic mixing" to "microscopic composite" of particles through precise control of atomization parameters, temperature and other processes. This is of irreplaceable importance for the performance optimization of NiO-YSZ particles: on the one hand, spray pyrolysis can avoid particle agglomeration and obtain submicron-sized secondary particles with uniform particle size, laying the foundation for the construction of porous electrode structures; on the other hand, the migration and reaction of components during its pyrolysis process can be precisely controlled, thereby forming special functional structures such as core and shell, realizing the three-dimensional connection between Ni (electronic conductor) and YSZ (oxygen ion conductor) and maximizing the TPB area.

[0041] Although some existing technologies disclose methods for preparing NiO-YSZ particles via spray pyrolysis, their application in NiO-YSZ particle preparation has significant limitations: most studies focus only on the synthesis of particles with simple hybrid structures, lacking precise design and control of high-performance structures such as cores and shells; more importantly, existing NiO@YSZ particles prepared by spray pyrolysis are mostly geared towards anode applications in solid oxide fuel cells (SOFCs), without structural optimization for the special operating conditions of SOEC water electrolysis for hydrogen production (such as high water vapor atmosphere and strong ion migration requirements). This results in the particles failing to fully utilize their performance in SOEC cathodes, exhibiting problems such as insufficient high-temperature electrolysis stability and insignificant reduction in polarization resistance. Therefore, this invention develops a method for controllably preparing core-shell structured, highly active, and highly stable NiO@YSZ nanocomposite particles based on spray pyrolysis technology for SOEC water electrolysis hydrogen production scenarios. This method not only fully leverages the core advantages of spray pyrolysis technology in structural regulation but also specifically addresses the performance pain points of SOEC hydrogen electrodes, which is of vital significance for improving the efficiency of water electrolysis for hydrogen production, reducing the cost of green hydrogen production, and promoting the industrialization of SOEC.

[0042] Based on this, the present invention specifically designed and prepared a NiO@YSZ nanocomposite material, which is a core-shell structured NiO@YSZ nanocomposite spherical particle with a specific surface morphology. The NiO@YSZ nanocomposite particles provided by the present invention have a shell mainly composed of NiO microcrystals and a core mainly composed of YSZ microcrystals, forming a three-dimensional interconnected structure of "electronic conductor-ionic conductor". The particles are functionally adapted to the SOEC hydrogen electrode, and the NiO@YSZ particles are fabricated into a cathode functional layer, precisely positioned between the cathode substrate and the electrolyte, maximizing the three-phase interface (TPB) active region.

[0043] This invention also provides a corresponding ultrasonic spray pyrolysis synthesis method for NiO@YSZ nanocomposite particles. By optimizing the design of parameters such as precursor ratio, spray parameters, and pyrolysis temperature gradient, the unique advantages of spray pyrolysis technology in microstructure control are fully utilized. Combined with the multi-parameter synergistic control of the spray pyrolysis process, precise control of the particle core-shell structure and morphology size is achieved, solving the problems of poor dispersion, uncontrollable structure, and insufficient adaptability to SOEC conditions of NiO@YSZ particles prepared by traditional methods. Furthermore, applying the NiO@YSZ core-shell structured nanoparticles prepared by the ultrasonic spray pyrolysis process of this invention to the functional layer of the SOEC hydrogen electrode can significantly reduce polarization resistance and improve the efficiency of hydrogen production from water electrolysis and the long-term stability of the device. In particular, the long-term stability is excellent: the core-shell structure inhibits Ni particle agglomeration at high temperatures, and the voltage decay rate of continuous SOEC electrolysis is only 2.3%, far superior to traditional electrodes. Moreover, the process is adaptable to large-scale applications: the spray pyrolysis process has a high degree of continuity, high precursor utilization, no secondary pollution, and can achieve batch production of particles.

[0044] This invention uses nickel nitrate, zirconium oxychloride, and yttrium nitrate as precursors, and synthesizes core-shell NiO@YSZ nanocomposite particles through high-energy ultrasonic atomization, instantaneous high-temperature pyrolysis, and high-voltage electrostatic collection. These particles are then applied to the functional layer of an SOEC hydrogen electrode through slurry preparation and process optimization to improve electrolytic stability. The particles are spherical particles with a size of hundreds of nanometers, with a shell mainly composed of NiO microcrystals and a core mainly composed of YSZ microcrystals, exhibiting a uniform particle size distribution (D). 50 With a particle size of 467.5 nm, the microcrystals exhibit excellent dispersion. Using these particles as a raw material for the functional layer of the SOEC hydrogen electrode allows for the construction of a highly active three-phase interface (TPB) and a continuous conductive / ion-conducting network, reducing cathode polarization resistance and ensuring stable voltage during SOEC hydrogen production at 800°C under constant current electrolysis. This invention offers a controllable synthesis process with significant scalability potential, providing a key hydrogen electrode functional layer material and preparation route for high-performance SOEC water electrolysis hydrogen production, and further facilitating the application of NiO@YSZ nanocomposite particles in the functional layer of the SOEC hydrogen electrode. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the reaction apparatus provided by the present invention;

[0046] Figure 2 SEM image of the NiO@YSZ composite nanospheres prepared in this invention;

[0047] Figure 3 The results of laser particle size analysis of the NiO@YSZ nanospheres prepared in this invention;

[0048] Figure 4 TEM image of the NiO@YSZ nanospheres prepared in this invention;

[0049] Figure 5 EDX image of the NiO@YSZ nanospheres prepared in this invention;

[0050] Figure 6 The XRD pattern of the NiO@YSZ nanospheres prepared in this invention;

[0051] Figure 7 A cross-sectional SEM image of the SOEC cell prepared according to the present invention;

[0052] Figure 8 Electrolysis current-time curve of a single cell prepared using the hydrogen electrode functional layer made from NiO@YSZ nanospheres prepared in this invention;

[0053] Figure 9 The results of laser particle size analysis are for the NiO-YSZ physically mixed particles prepared in Comparative Example 1 of this invention.

[0054] Figure 10 Electrolysis current-time curve of a single cell prepared from the NiO-YSZ physically mixed hydrogen electrode functional layer prepared in Comparative Example 1 of this invention. Detailed Implementation

[0055] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0056] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0057] There are no particular restrictions on the purity of any raw materials used in this invention. However, this invention preferably uses analytical grade or conventional purity used in the preparation of hydrogen electrode functional layers for solid oxide electrolytic cells.

[0058] This invention provides a NiO@YSZ nanocomposite material, comprising a YSZ core and a NiO shell coating the YSZ core;

[0059] The NiO@YSZ nanocomposite material consists of spherical particles with a core-shell structure.

[0060] The NiO shell has a wrinkled surface morphology.

[0061] In this invention, the NiO@YSZ nanocomposite particles are preferably submicron-sized particles.

[0062] In this invention, the particle size of the NiO@YSZ nanocomposite material particles can be 360~660 nm, 400~600 nm, or 450~550 nm.

[0063] In this invention, the particle size distribution span (SPAN) of the NiO@YSZ nanocomposite material can be 0.39~0.46, 0.40~0.45, 0.41~0.44, or 0.42~0.43.

[0064] In this invention, the surface morphology of the wrinkles is preferably a wrinkle morphology formed by the stacking of nanosheets.

[0065] In this invention, the YSZ core preferably includes a YSZ spherical core.

[0066] In this invention, the YSZ core is preferably a microcrystalline dense core formed by the aggregation of YSZ nanoparticles.

[0067] In this invention, the NiO shell is preferably a porous shell.

[0068] In this invention, the thickness of the NiO shell can be 30~50 nm, 34~46 nm, or 38~42 nm.

[0069] In this invention, the mass ratio of NiO to YSZ can be (1~2):1, (1.2~1.8):1, or (1.4~1.6):1.

[0070] In this invention, the NiO@YSZ nanocomposite material is preferably a NiO@YSZ nanocomposite material synthesized by spray pyrolysis.

[0071] In this invention, the NiO@YSZ nanocomposite material preferably includes a composite material for the SOEC hydrogen electrode functional layer.

[0072] In this invention, the NiO shell is preferably a porous shell formed by stacking NiO nanoparticles.

[0073] This invention provides the application of ultrasonic spray pyrolysis synthesis method in the preparation of NiO@YSZ nanocomposites as described in any of the above technical solutions.

[0074] This invention provides a method for preparing NiO@YSZ nanocomposite materials according to any one of the above technical solutions, comprising the following steps:

[0075] 1) A mixed solution is obtained by mixing nickel nitrate, zirconium oxychloride, yttrium nitrate, and water;

[0076] 2) The mixed solution obtained in the above steps is subjected to ultrasonic spray pyrolysis synthesis. First, the mixed solution is ultrasonically atomized to obtain atomized droplets. Then, under the action of a carrier gas, the atomized droplets are passed through the heating zone for pyrolysis, and the pyrolysis product NiO@YSZ nanocomposite material is collected.

[0077] The present invention first mixes nickel nitrate, zirconium oxychloride, yttrium nitrate and water to obtain a mixed solution.

[0078] In this invention, the total concentration of cations in the mixed solution can be 0.05~0.5 mol / L, 0.15~0.4 mol / L, or 0.25~0.3 mol / L.

[0079] In this invention, the mixed solution obtained in the above steps is further synthesized by ultrasonic spray pyrolysis. First, the mixed solution is ultrasonically atomized to obtain atomized droplets. Then, under the action of a carrier gas, the atomized droplets are passed through a heating zone for pyrolysis, and the pyrolysis product NiO@YSZ nanocomposite material is collected.

[0080] In this invention, the mass ratio of NiO and YSZ in the mixed solution can be (1~2):1, (1.2~1.8):1, or (1.4~1.6):1.

[0081] In this invention, the molar content of yttrium oxide in the YSZ can be 3YSZ~8YSZ, 4YSZ~7YSZ, or 5YSZ~6YSZ. Specifically, based on common knowledge in the art, 3YSZ, i.e., yttrium-stabilized zirconium oxide, has a molar content of 3% yttrium oxide, while 8YSZ has a molar content of 8% yttrium oxide.

[0082] In this invention, the ultrasonic frequency of the ultrasonic atomization can be 1~2MHz, 1.2~1.8MHz, or 1.4~1.6MHz.

[0083] In this invention, the carrier gas preferably includes an oxygen-containing gas.

[0084] In this invention, the flow rate of the carrier gas can be 1~2L / min, 1.2~1.8L / min, or 1.4~1.6L / min.

[0085] In this invention, the pyrolysis temperature can be 600~1000℃, 650~950℃, 700~900℃, or 750~850℃.

[0086] In this invention, the pyrolysis time can be 0.5 to 2 seconds, 0.8 to 1.7 seconds, or 1.1 to 1.4 seconds.

[0087] This invention provides an apparatus for preparing NiO@YSZ nanocomposite materials as described in any one of the above technical solutions, comprising:

[0088] Ultrasonic atomizing device;

[0089] The precursor solution source is connected to the liquid inlet of the ultrasonic atomizing device;

[0090] A carrier gas source connected to the air inlet of the ultrasonic atomizing device;

[0091] A pyrolysis reaction device connected to the droplet mixture outlet of the ultrasonic atomizing device;

[0092] A product collection device connected to the outlet of the pyrolysis reaction apparatus.

[0093] The present invention provides a solid oxide electrolytic cell, wherein the solid oxide electrolytic cell comprises the NiO@YSZ nanocomposite material described in any one of the above technical solutions or the NiO@YSZ nanocomposite material prepared by the preparation method described in any one of the above technical solutions.

[0094] The present invention also provides the application of the NiO@YSZ nanocomposite material described in any one of the above technical solutions or the NiO@YSZ nanocomposite material prepared by the preparation method described in any one of the above technical solutions in a solid oxide electrolytic cell.

[0095] This invention aims to complete and refine the overall preparation process, further ensuring the specific morphology and properties of the NiO@YSZ core-shell nanosphere composite material, and further improving the performance of the NiO@YSZ nanocomposite material as a functional layer for SOEC hydrogen electrodes. Specifically, the aforementioned SOEC hydrogen electrode functional layer based on NiO@YSZ core-shell nanospheres, its preparation method, preparation apparatus, and a solid oxide electrolytic cell may include the following:

[0096] The technical solution provided by this invention revolves around the spray pyrolysis synthesis process of NiO@YSZ nanocomposite particles and its application in SOEC hydrogen electrodes. The core parameters and structural design are as follows:

[0097] Optimization of precursor solutions:

[0098] Nickel nitrate (Ni(NO3)2·6H2O), zirconium oxychloride (ZrOCl2·8H2O), and yttrium nitrate (Y(NO3)3·6H2O) were selected as water-soluble precursors, and a total cation concentration of 0.1 mol·L⁻¹ was prepared by mixing NiO and YSZ at a weight ratio of 60:40. -1 A mixed solution.

[0099] This ratio ensures a balance between the proportions of Ni (electronic conductor, catalyzing water splitting to produce hydrogen) and YSZ (oxygen ion conductor, transporting oxygen ions) after reduction, while the water-soluble precursor ensures uniform composition of the atomized droplets, laying the foundation for precise structural control during spray pyrolysis.

[0100] Spray pyrolysis process parameter control (demonstrating core technological advantages):

[0101] Atomization method: A 1.75 MHz ultrasonic vibrator is used to ensure uniform droplet size and avoid subsequent uneven particle morphology and agglomeration. This is the core step for achieving precise particle size control in spray pyrolysis technology.

[0102] Carrier gas and flow rate: Using air as the carrier gas can stably carry droplets through the heating zone and provide an oxidizing atmosphere for nitrate decomposition, avoiding premature reduction of precursors and ensuring the purity of particle components;

[0103] Temperature settings: Droplet dehydration, nitrate decomposition, preliminary oxide reaction and crystallization densification are achieved sequentially. By utilizing the migration differences between Ni compounds and Zr / Y compounds during pyrolysis, a core-shell structure of "YSZ core-NiO shell" is formed in a directional manner. This ability to regulate the structure is the core advantage of spray pyrolysis technology that distinguishes it from traditional methods, and it is also the key to adapting NiO@YSZ particles to the requirements of SOEC cathodes.

[0104] Particle structure and SOEC hydrogen electrode adaptation design:

[0105] The NiO@YSZ particles synthesized by spray pyrolysis have a core-shell structure of "YSZ core-NiO shell," with a porous shell and a dense core. After reduction, NiO is converted into Ni, forming a Ni@YSZ composite structure: the Ni shell provides abundant catalytic active sites and electron conduction capabilities, accelerating the water splitting to produce hydrogen; the YSZ core provides continuous oxygen ion conduction channels, reducing ion transport resistance; the three-dimensional interconnected network derived from the core-shell structure significantly increases the TPB area and reduces charge transfer resistance, perfectly meeting the reaction requirements of SOEC high-temperature water electrolysis. The realization of this high-performance structure relies entirely on the precise control of the particle formation process by spray pyrolysis technology.

[0106] SOEC hydrogen electrode functional layer application process: NiO@YSZ nanocomposite particles are prepared into a slurry and screen-printed onto the surface of a NiO-YSZ hydrogen electrode support. This slurry is then co-sintered with the YSZ electrolyte layer to form a cathode functional layer located between the hydrogen electrode support and the electrolyte. This ensures close contact with the electrolyte while allowing for concentrated water splitting to produce hydrogen through the highly active TPB region. The high dispersibility and structural stability of the particles prepared by spray pyrolysis ensure that the functional layer maintains its excellent microstructure even after high-temperature sintering.

[0107] See Figure 1 , Figure 1 This is a schematic diagram of the reaction apparatus provided by the present invention. Wherein, 1 is a carrier gas; 2 is a precursor solution; 3 is a peristaltic pump; 4 is an ultrasonic atomizing device; 5 is a flow meter; 6 is a tubular furnace (pyrolysis reaction apparatus); 7 is a high-voltage electrostatic collection device; 8 is a high-voltage power supply; and 9 is a tail gas treatment device.

[0108] Specifically, the detailed design and operating principle of the spray pyrolysis equipment.

[0109] Ultrasonic atomization device:

[0110] Ultrasonic action breaks down the solution into droplets, creating hollow oxide structures. During industrial scale-up, increasing the number of gas atomizers and employing a lattice arrangement significantly improves atomization efficiency, meeting the demands of large-scale production.

[0111] A specially designed feed delivery system is used to precisely control the flow rate of the precursor solution, ensuring the stability of the atomization process. A high-precision peristaltic pump is employed, with a flow rate accuracy controlled within ±0.1%, ensuring a stable supply of precursor solution during long-term operation and thus guaranteeing consistent product quality.

[0112] Pyrolysis reactor:

[0113] The reactor employs a tubular resistance furnace structure, with an internal quartz tube serving as the reaction chamber. This structure provides a uniform and stable high-temperature environment, which is beneficial for the pyrolysis reaction of droplets. In the laboratory stage, the heating power of the tubular resistance furnace can be precisely controlled to ensure the accuracy of the reaction temperature. In industrial production, by optimizing the heating wire distribution and temperature control system of the resistance furnace, uniform temperature control of a large-area reaction zone can be achieved, with a deviation not exceeding ±5℃.

[0114] A special design is employed for the airflow distribution in the reactor. By installing a gas distributor at the inlet, the carrier gas can be uniformly mixed with the atomized droplets, forming a stable airflow field within the reaction chamber. This ensures that the droplets maintain a consistent trajectory and residence time during pyrolysis, thereby improving product uniformity.

[0115] Powder collection system:

[0116] A multi-stage bubbling water absorption method combined with cyclone separation technology is employed. First, the gas-powder mixture passes through a cyclone separator, where centrifugal force separates most of the larger powder particles. The remaining gas containing fine particles enters the multi-stage bubbling water absorption device, where the powder is captured by the water during the bubbling process, achieving the dual purpose of exhaust gas treatment and powder collection.

[0117] This invention provides a functional layer for an SOEC hydrogen electrode based on NiO@YSZ core-shell nanospheres, along with its preparation method, apparatus, and a solid oxide electrolytic cell. The NiO@YSZ nanocomposite material specifically designed in this invention is a core-shell structure of NiO@YSZ nanocomposite spherical particles with a specific surface morphology. The NiO@YSZ nanocomposite particles provided by this invention have a shell primarily composed of NiO microcrystals and a core primarily composed of YSZ microcrystals, forming a three-dimensional interconnected structure of "electronic conductor-ion conductor." The particles are functionally adapted to the SOEC hydrogen electrode, and the NiO@YSZ particles are fabricated into a cathode functional layer, precisely positioned between the cathode substrate and the electrolyte, maximizing the three-phase interface (TPB) active region.

[0118] This invention also provides a corresponding ultrasonic spray pyrolysis synthesis method for NiO@YSZ nanocomposite particles. By optimizing the design of parameters such as precursor ratio, spray parameters, and pyrolysis temperature gradient, the unique advantages of spray pyrolysis technology in microstructure control are fully utilized. Combined with the multi-parameter synergistic control of the spray pyrolysis process, precise control of the particle core-shell structure and morphology size is achieved, solving the problems of poor dispersion, uncontrollable structure, and insufficient adaptability to SOEC conditions of NiO@YSZ particles prepared by traditional methods. Furthermore, applying the NiO@YSZ core-shell structured nanoparticles prepared by the ultrasonic spray pyrolysis process of this invention to the functional layer of the SOEC hydrogen electrode can significantly reduce polarization resistance and improve the efficiency of hydrogen production from water electrolysis and the long-term stability of the device. In particular, the long-term stability is excellent: the core-shell structure inhibits Ni particle agglomeration at high temperatures, and the voltage decay rate of continuous SOEC electrolysis is only 2.3%, far superior to traditional electrodes. Moreover, the process is adaptable to large-scale applications: the spray pyrolysis process has a high degree of continuity, high precursor utilization, no secondary pollution, and can achieve batch production of particles.

[0119] This invention uses nickel nitrate, zirconium oxychloride, and yttrium nitrate as precursors, and synthesizes core-shell NiO@YSZ nanocomposite particles through high-energy ultrasonic atomization, instantaneous high-temperature pyrolysis, and high-voltage electrostatic collection. These particles are then applied to the functional layer of an SOEC hydrogen electrode through slurry preparation and process optimization to improve electrolytic stability. The particles are spherical particles with a size of hundreds of nanometers, with a shell mainly composed of NiO microcrystals and a core mainly composed of YSZ microcrystals, exhibiting a uniform particle size distribution (D). 50 With a particle size of 467.5 nm, the microcrystals exhibit excellent dispersion. Using these particles as a raw material for the functional layer of the SOEC hydrogen electrode allows for the construction of a highly active three-phase interface (TPB) and a continuous conductive / ion-conducting network, reducing cathode polarization resistance and ensuring stable voltage during SOEC hydrogen production at 800°C under constant current electrolysis. This invention offers a controllable synthesis process with significant scalability potential, providing a key hydrogen electrode functional layer material and preparation route for high-performance SOEC water electrolysis hydrogen production, and further facilitating the application of NiO@YSZ nanocomposite particles in the functional layer of the SOEC hydrogen electrode.

[0120] To further illustrate the present invention, the following detailed description of a NiO@YSZ nanocomposite material, its preparation method, preparation apparatus, and a solid oxide electrolytic cell provided by the present invention is provided in conjunction with embodiments. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures, only to further illustrate the features and advantages of the present invention, and not to limit the scope of protection of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0121] Example 1

[0122] Spray pyrolysis synthesis of NiO@YSZ nanocomposite particles

[0123] Precursor solution preparation: Weigh Ni(NO3)2·6H2O, ZrOCl2·8H2O, and Y(NO3)3·6H2O. Calculate the raw material amounts based on a NiO to YSZ weight ratio of 60:40. Dissolve in distilled water and stir for 30 min until completely dissolved to prepare a total cation concentration of 0.1 mol·L⁻¹. -1 A mixed nitrate solution. The reaction apparatus is as follows: Figure 1 As shown, it includes an ultrasonic atomization zone, an instantaneous heating zone, and a particle collection zone.

[0124] Ultrasonic atomization: The above solution is fed into the atomization zone of the spray pyrolysis device, and a 1.75 MHz ultrasonic vibrator is started to atomize the solution into uniform droplets.

[0125] Instantaneous pyrolysis: Using air as the carrier gas at a flow rate of 2 L / min, the atomized droplets are sent into the heating zone and passed through an electric furnace at 900℃, where the droplets are gradually transformed into nanocomposite particles.

[0126] Particle collection: The pyrolysis products are collected through a polymer filter to obtain NiO@YSZ nanocomposite particles.

[0127] See Figure 2 , Figure 2 This is a SEM image of the NiO@YSZ composite nanospheres prepared in this invention.

[0128] Morphology and size: FE-SEM observation shows that the particles are spherical, such as... Figure 2 As shown, the surface is slightly rough.

[0129] See Figure 3 , Figure 3 The results of laser particle size analysis of the NiO@YSZ nanospheres prepared in this invention are shown.

[0130] Tested by a laser particle size analyzer ( Figure 3 ), narrow particle size distribution (D 10 =379.1 nm, D 50 =467.5 nm, D 90 =564.9nm);

[0131] See Figure 4 , Figure 4 This is a TEM image of the NiO@YSZ nanospheres prepared in this invention.

[0132] See Figure 5 , Figure 5 The image shows the EDX diagram of the NiO@YSZ nanospheres prepared in this invention.

[0133] like Figure 4 , 5The TEM and EDX images shown confirm that the particles have a core-shell structure, with the shell rich in Ni (NiO) and the core rich in Zr / Y (YSZ).

[0134] See Figure 6 , Figure 6 The image shows the XRD pattern of the NiO@YSZ nanospheres prepared in this invention.

[0135] Crystal structure: such as Figure 6 As shown, XRD analysis indicates that NiO@YSZ was successfully synthesized without any impurity phases.

[0136] Fabrication of SOEC hydrogen electrode support based on NiO@YSZ

[0137] Preparation of hydrogen electrode support:

[0138] 360g of NiO powder, 240g of 8YSZ powder, 22g of 1200-mesh graphite powder, and 270mL of anhydrous ethanol were placed into a 500mL ball mill jar and ground and mixed at 300rpm for 24 hours. The mixture was then dried for later use.

[0139] Take 530g of the above mixed powder, add PVP and anhydrous ethanol solvent, grind at 200rpm for 12 hours, then add PVB, polyethylene glycol and other additives to prepare a hydrogen electrode support slurry. Perform a casting process on the slurry, dry at room temperature for 2 days, and cut the green sheet into 20mm diameter discs for later use.

[0140] Preparation of cathode functional layer slurry:

[0141] The solvent for the hydrogen electrode functional layer was prepared using terpineol, ethyl cellulose, PVB, and dibutyl phthalate. The NiO@YSZ powder prepared above, comprising 70% of the total mass, was then used. The solvent was dispersed by stirring in a high-energy ball mill at 300 rpm for 12 hours to form a homogeneous slurry.

[0142] Cathode functional layer printing and co-sintering:

[0143] The paste is coated onto the surface of the pre-sintered cathode substrate by screen printing, and then the YSZ electrolyte paste is printed onto the surface of the cathode functional layer to form a three-layer component of "cathode substrate-cathode functional layer-electrolyte". The component is co-sintered in an air atmosphere at a maximum sintering temperature of 1390℃ to obtain a half cell containing a NiO@YSZ cathode functional layer.

[0144] SOEC complete assembly:

[0145] A GDC separator layer was screen-printed on the other side of the YSZ electrolyte in the half-cell and sintered at a maximum temperature of 1250℃; then, an LSCF-GDC oxygen electrode paste was printed and sintered at a maximum temperature of 1000℃ to obtain a complete SOEC. The cross-sectional SEM image of the cell is shown below. Figure 7 As shown.

[0146] See Figure 7 , Figure 7 This is a cross-sectional SEM image of the SOEC battery prepared according to the present invention.

[0147] SOEC water electrolysis hydrogen production performance test

[0148] Hydrogen is introduced into the electrode at a rate of 60 mL / min. -1 3% humidified H2, 70 mL·min at the anode -1 The air was reduced at high temperature for 2 hours to completely convert NiO into Ni.

[0149] Electrolysis stage: 40℃ water vapor is introduced into the hydrogen electrode, and 70 mL·min⁻¹ water vapor is introduced into the anode. -1 The air was used for electrolysis at a temperature of 600~800℃, and constant current electrolysis durability test was conducted using an electrochemical workstation.

[0150] Durability: After 200 hours of continuous water electrolysis for hydrogen production at 800℃, the electrolysis voltage decay rate was 2.3%. Figure 8 As shown.

[0151] See Figure 8 , Figure 8 Electrolysis current-time curve of a single cell prepared using the hydrogen electrode functional layer made from NiO@YSZ nanospheres prepared in this invention.

[0152] Comparative Example 1

[0153] SOEC performance of conventionally mechanically mixed NiO-YSZ particles

[0154] NiO and YSZ powders were mixed in a ball mill to obtain NiO-YSZ physically mixed particles (NiO to YSZ weight ratio 60:40). The remaining SOEC preparation process was the same as in Example 1. Because the sizes of the two types of particles differed significantly, the laser particle size analyzer showed that the particle size distributions of the two groups were not uniform.

[0155] See Figure 9 , Figure 9 The results of laser particle size analysis are for the NiO-YSZ physically mixed particles prepared in Comparative Example 1 of this invention.

[0156] During the preparation of the functional layer slurry, a significant delamination phenomenon was observed between the green NiO and the white YSZ, resulting in uneven screen-printed hydrogen electrode functional coating. This, in turn, led to uneven thermal stress in the battery after high-temperature sintering, causing cracks. The SOEC prepared from this mixture failed to maintain long-term stability under electrolysis conditions at 800℃, exhibiting severe degradation after 70 hours. Its performance was significantly lower than that of the NiO@YSZ core-shell structure hydrogen electrode functional layer described in Example 1, fully demonstrating the absolute structural and performance advantages of NiO@YSZ particles prepared by spray pyrolysis technology.

[0157] See Figure 10 , Figure 10 Electrolysis current-time curve of a single cell prepared from the NiO-YSZ physically mixed hydrogen electrode functional layer prepared in Comparative Example 1 of this invention.

[0158] The foregoing has provided a detailed description of the SOEC hydrogen electrode functional layer based on NiO@YSZ core-shell nanospheres, its preparation method, preparation apparatus, and a solid oxide electrolytic cell provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the textual description of the claims, or if they include equivalent structural elements that are not substantially different from the textual description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A NiO@YSZ nanocomposite material, characterized in that, This includes the YSZ core and the NiO shell covering the YSZ core; The NiO@YSZ nanocomposite material consists of spherical particles with a core-shell structure. The NiO shell has a wrinkled surface morphology.

2. The NiO@YSZ nanocomposite material according to claim 1, characterized in that, The NiO@YSZ nanocomposite particles are submicron-sized particles; The particle size of the NiO@YSZ nanocomposite material is 360~660 nm; The particle size distribution span (SPAN) of the NiO@YSZ nanocomposite material is 0.39~0.46; The surface morphology of the folds is specifically a fold morphology formed by the stacking of nanosheets.

3. The NiO@YSZ nanocomposite material according to claim 1, characterized in that, The YSZ core includes a YSZ spherical core; The YSZ core is specifically a microcrystalline dense core formed by the aggregation of YSZ nanoparticles. The NiO shell is a porous shell; The thickness of the NiO shell is 30~50 nm.

4. The NiO@YSZ nanocomposite material according to claim 1, characterized in that, The mass ratio of NiO to YSZ is (1~2):1; The NiO@YSZ nanocomposite material is a NiO@YSZ nanocomposite material synthesized by spray pyrolysis; The NiO@YSZ nanocomposite material includes a composite material used for the SOEC hydrogen electrode functional layer; The NiO shell is specifically a porous shell formed by stacking NiO nanoparticles.

5. Application of ultrasonic spray pyrolysis synthesis method in the preparation of NiO@YSZ nanocomposite materials according to any one of claims 1 to 4.

6. A method for preparing NiO@YSZ nanocomposite material as described in any one of claims 1 to 4, characterized in that, Includes the following steps: 1) A mixed solution is obtained by mixing nickel nitrate, zirconium oxychloride, yttrium nitrate, and water; 2) The mixed solution obtained in the above steps is subjected to ultrasonic spray pyrolysis synthesis. First, the mixed solution is ultrasonically atomized to obtain atomized droplets. Then, under the action of a carrier gas, the atomized droplets are passed through the heating zone for pyrolysis, and the pyrolysis product NiO@YSZ nanocomposite material is collected.

7. The preparation method according to claim 6, characterized in that, The total concentration of cations in the mixed solution is 0.05~0.5 mol / L; In the mixed solution, the mass ratio of NiO and YSZ is (1~2):1; The molar content of yttrium oxide in the YSZ is 3YSZ~8YSZ.

8. The preparation method according to claim 6, characterized in that, The ultrasonic frequency of the ultrasonic atomization is 1~2MHz; The carrier gas includes oxygen-containing gas; The flow rate of the carrier gas is 1~2L / min; The pyrolysis temperature is 600~1000℃; The pyrolysis time is 0.5 to 2 seconds.

9. An apparatus for preparing NiO@YSZ nanocomposite materials as described in any one of claims 1 to 4, characterized in that, include: Ultrasonic atomizing device; The precursor solution source is connected to the liquid inlet of the ultrasonic atomizing device; A carrier gas source connected to the air inlet of the ultrasonic atomizing device; A pyrolysis reaction device connected to the droplet mixture outlet of the ultrasonic atomizing device; A product collection device connected to the outlet of the pyrolysis reaction apparatus.

10. A solid oxide electrolytic cell, characterized in that, The solid oxide electrolytic cell includes the NiO@YSZ nanocomposite material according to any one of claims 1 to 4 or the NiO@YSZ nanocomposite material prepared by the preparation method according to any one of claims 6 to 8.

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