Ni-Fe alloy supported solid oxide fuel cell and preparation method thereof

Abstract

The invention discloses a Ni-Fe alloy supported solid oxide fuel cell and a preparation method thereof, and belongs to the technical field of solid oxide fuel cells. The battery comprises a Ni-Fe alloy supporting structure and stacked single battery pieces, wherein the Ni-Fe alloy supporting structure is in a grid shape and is prepared through Ni-Fe alloy powder metallurgy or additive manufacturing; the Ni content of the Ni-Fe alloy supporting structure ranges from 30 wt% to 40 wt%, and the thermal expansion coefficient ranges from (11.2 * 10 <-6 > K <-1 > to 11.8) * 10 <-6 > K <-1 >. The side length of the grid shape ranges from 1.5 mm to 2.5 mm, the thickness of the grid shape ranges from 0.4 mm to 0.6 mm, the aperture ratio ranges from 50% to 70%, and the grid spacing ranges from 4.0 mm to 5.0 mm. Through thermal expansion matching of the Ni-Fe alloy, optimal design of the latticed structure and improvement of the conductivity, the thermal cycling stability, the electrochemical performance, the mechanical stability and the multi-fuel adaptability of the electric pile are remarkably improved, meanwhile, the cost effectiveness is considered, and a solid foundation is laid for wide application of the SOFC in the field of clean energy.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid oxide fuel cells (SOFC), and particularly relates to a Ni-Fe alloy supported solid oxide fuel cell and a preparation method thereof. BACKGROUND

[0002] A solid oxide fuel cell (SOFC) is a high-efficiency and environmentally friendly energy conversion device, which has attracted much attention due to its high energy conversion efficiency and wide application prospects. A SOFC stack is usually composed of multiple cell sheets and a support structure, and the support structure is usually made of metal materials such as stainless steel. However, the traditional stainless steel support structure has significant defects at the working temperature (600℃-1000℃) of SOFC. For example, due to the large difference between the thermal expansion coefficient (about 16×10 -6 K -1 ~18×10 -6 K -1 ) of stainless steel and the thermal expansion coefficient (about 10×10 -6 K -1 ~12×10 -6 K -1 ) of SOFC cell sheets (mainly made of ceramic materials), a large thermal stress will be generated during thermal cycling (e.g., from room temperature to 800℃), which will cause cell sheet cracking, interface peeling or overall stack failure, and severely limits the long-term stability and service life of the stack.

[0003] In addition, as part of current collection, the electrical conductivity of the support material directly affects the output power of the SOFC stack. Due to the high resistivity (about 75μΩ•cm) of the stainless steel support material, the inherent electrical conductivity defect of this material will cause a decrease in current transmission efficiency, which will in turn restrict the overall performance of the stack. From the perspective of stack performance optimization, improving the electrical conductivity of the support material has become a core path to break through the current efficiency bottleneck, and the technical improvement in this link will directly affect the improvement of the energy conversion efficiency of the SOFC stack.

[0004] Application Content To solve the above problems, the present application provides a Ni-Fe alloy supported solid oxide fuel cell and a preparation method thereof. By utilizing the adjustable thermal expansion characteristics of Ni-Fe alloy, the ratio of Ni and Fe is adjusted to match the thermal expansion coefficient of the support structure with that of the SOFC cell sheet. At the same time, the low resistivity of the Ni-Fe alloy helps to significantly improve the output power of the stack.

[0005] In a first aspect, the present application provides a Ni-Fe alloy supported solid oxide fuel cell, comprising a Ni-Fe alloy support structure and a stack of single cell sheets; wherein, The Ni-Fe alloy support structure is in the shape of a mesh and is prepared by Ni-Fe alloy powder metallurgy or additive manufacturing; the Ni content of the Ni-Fe alloy support structure is 30wt%~40wt%, and the coefficient of thermal expansion is (11.2~11.8)×10. -6 K -1 ; The mesh has a side length of 1.5mm to 2.5mm, a thickness of 0.4mm to 0.6mm, an opening rate of 50% to 70%, and a mesh spacing of 4.0mm to 5.0mm.

[0006] Furthermore, the Ni-Fe alloy is prepared by the following method: Ni-Fe alloy raw material is obtained by mixing Ni powder and Fe powder; After pretreatment, the Ni-Fe alloy raw material is subjected to vacuum melting to obtain an alloy ingot; The alloy ingot is heat-treated to obtain a Ni-Fe alloy.

[0007] Furthermore, the preprocessing includes the following steps: The Ni-Fe alloy raw material was pickled in a 5% hydrochloric acid solution for 12 to 20 minutes. The pickled Ni-Fe alloy raw material was placed in deionized water and ultrasonically cleaned at a frequency of 35kHz~40kHz for 15min~20min. After removal, it was dried at 110℃~130℃ for 1.5h~2.5h.

[0008] Furthermore, the vacuum melting process includes the following steps: Add 0.05wt%~0.15wt% cerium powder and 0.02wt%~0.05wt% yttrium powder, and melt at 1540℃~1560℃ for 40min~50min; After melting, the mixture is cooled to room temperature at a rate of 110℃ / s to 120℃ / s under the protection of argon gas.

[0009] Furthermore, the heat treatment temperature is 900℃~980℃, the heat treatment time is 3h~4h, the heat treatment atmosphere is argon, and the cooling rate after heat treatment is 2℃ / min~5℃ / min.

[0010] Furthermore, the Ni-Fe alloy support structure is prepared by additive manufacturing, including the following steps: Take Ni-Fe alloy powder with a particle size of 15μm~45μm; The Ni-Fe alloy powder was prepared into a mesh-like preform by selective area laser melting; The mesh-like preform was sintered in a hydrogen atmosphere at 1300℃~1350℃ for 3h~4h to obtain the preform.

[0011] Furthermore, the Ni-Fe alloy support structure is prepared by powder metallurgy, including the following steps: Ni-Fe alloy powder with a particle size of 15μm~45μm was used to prepare a mesh-like blank by high pressure forming; wherein the pressure of high pressure forming was 250MPa~300MPa.

[0012] Furthermore, the laser power of the selective laser melting is 180W~300W, the scanning speed is 700mm / s~900mm / s, and the powder layer thickness is 45μm~55μm.

[0013] Furthermore, the single cell includes a Ni-YSZ anode with a thickness of 180μm~220μm, a YSZ electrolyte with a thickness of 8μm~12μm, and an LSM cathode with a thickness of 40μm~60μm. This application also discloses a method for preparing a Ni-Fe alloy supported solid oxide fuel cell, comprising the following steps: The single cells are stacked, and an 8μm~12μm thick NiO-YSZ transition layer is screen-printed between the bottom surface of the stacked single cells and the top surface of the Ni-Fe alloy support structure to assemble the fuel cell stack. The fuel cell stack is prepared by pre-sintering at 1050℃~1150℃ for 0.5h~1.5h under a hydrogen-nitrogen mixed gas and a pressure of 4.5kPa~5.5kPa, followed by sintering at 1300℃~1320℃ for 2.5h~3.5h; wherein the volume ratio of hydrogen to nitrogen in the hydrogen-nitrogen mixed gas is 1:8.

[0014] Furthermore, it also includes: preparing an Al2O3 anti-oxidation coating with a thickness of 1.5μm~2.5μm on the surface of the Ni-Fe alloy support structure by plasma spraying; wherein the plasma spraying power is 30kW and the spraying distance is 100mm.

[0015] The technical solutions provided in this application have at least the following advantages compared with the prior art: This application selects Ni-Fe alloy as the support material and optimizes its thermal expansion coefficient by precisely controlling the alloy composition to match it with the thermal expansion coefficient of SOFC cells, effectively improving the thermal cycling stability and conductivity of the stack. It effectively solves the problem of thermal expansion mismatch between traditional support materials and ceramic cells under high-temperature conditions, while simultaneously improving the overall electrical performance of the stack through the conductivity advantages of the alloy material. This provides assurance for the efficient and stable operation of the stack from both thermal matching and conductivity perspectives. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the Ni-Fe alloy supported solid oxide fuel cell (MS-SOFC) provided in Example 1.

[0017] Figure 2 This diagram illustrates the relationship between the coefficient of thermal expansion of Ni-Fe alloys and Ni content. The optimal Ni content is 35 wt%, corresponding to a coefficient of thermal expansion of 11.5 × 10⁻⁶. -6 K -1 .

[0018] Figure 3 The results show the stack thermal cycling stability test results of the Ni-Fe alloy supported solid oxide fuel cell (MS-SOFC) provided in Example 1.

[0019] Figure 4 A comparison of the electrical performance of the Ni-Fe alloy-supported fuel cell stack provided in Example 1 and the conventional stainless steel-supported fuel cell stack at 800°C (H2 flow rate 0.5 L / min, air flow rate 2 L / min). Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this application can be purchased on the market or prepared by existing methods.

[0021] Existing technologies typically optimize SOFC stack performance by improving the materials or structure of the support structure. For example, nickel-based or cobalt-based alloys are used instead of stainless steel to improve the high-temperature resistance and conductivity of the support material. However, these new alloys are expensive, hindering their large-scale application; furthermore, the matching of thermal expansion coefficients with SOFC cells remains unsatisfactory. For instance, thermal stress problems are mitigated by optimizing electrode microstructures or using functionally graded materials. However, these methods primarily focus on the cell itself and do not adequately consider the comprehensive optimization of the support structure. Therefore, existing technologies still have limitations in the synergistic optimization of the thermal expansion matching and conductivity of the support material.

[0022] In a first aspect, this application provides a Ni-Fe alloy-supported solid oxide fuel cell, comprising a Ni-Fe alloy support structure and stacked single cells; wherein the Ni-Fe alloy support structure is mesh-like in shape and is prepared by Ni-Fe alloy powder metallurgy or additive manufacturing; the Ni content of the Ni-Fe alloy support structure is 30wt%~40wt%, the resistivity is 22μΩ•cm, and the coefficient of thermal expansion is (11.2~11.8)×10⁻⁶. -6 K -1 The mesh has a side length of 1.5mm to 2.5mm, a thickness of 0.4mm to 0.6mm, an opening rate of 50% to 70%, and a mesh spacing of 4.5mm.

[0023] In the above scheme, Ni-Fe alloy is used as the supporting material, and precise composition control and grid structure design are combined to form a systematic solution: First, by precisely controlling the Ni content in the Ni-Fe alloy to 30wt%~40wt% (preferably 35wt%), the coefficient of thermal expansion of the material is stabilized at (11.2~11.8)×10. -6 K -1 The thermal expansion range of SOFC cells (10×10) -6 K -1 ~12×10 -6 K -1 The high degree of compatibility successfully reduced the thermal cycling stress from 250 MPa to 140 MPa, significantly improving interfacial compatibility. Secondly, leveraging the low resistivity of the Ni-Fe alloy (22 μΩ•cm), the power density of the SOFC stack was increased to 0.8 W / cm². 2 Simultaneously, the electrochemical conversion efficiency was optimized. Finally, the mesh-like support structure (side length 1.5mm~2.5mm, thickness 0.4mm~0.6mm, and porosity 50%~70%) optimized through finite element analysis not only achieved uniform thermal stress distribution but also improved airflow distribution efficiency and enhanced mechanical stability through structural design. This breakthrough overcomes the shortcomings of traditional support materials from two dimensions: intrinsic material properties (thermal matching, conductivity) and structural functions (stress dispersion, airflow optimization). It achieves a comprehensive balance in performance improvement, durability enhancement, and cost control, opening up a new technical path for the large-scale commercial application of SOFC technology.

[0024] In the preferred embodiment of this application, the Ni-Fe alloy support structure has a Ni content of 35 wt%, a resistivity of 22 μΩ•cm, and a coefficient of thermal expansion of 11.5 × 10⁻⁶. -6 K -1 The mesh has a side length of 2mm, a thickness of 0.5mm, an opening ratio of 65%, and a mesh spacing of 4.5mm.

[0025] When the Ni content is below 30wt% or above 40wt%, the coefficient of thermal expansion of the Ni-Fe alloy will deviate from the matching range of SOFC cells (10×10). -6 K -1 ~12×10 -6 K -1 This leads to stress concentration during thermal cycling. Through systematic verification of thermal compatibility, oxidation resistance, and electrical properties, this application has determined that 35wt% Ni is the optimal alloying ratio: at this ratio, the coefficient of thermal expansion is optimized to 11.5 × 10⁻⁶. -6 K -1 Precise matching with the solar cells reduced thermal cycling stress from 250 MPa to 140 MPa, a reduction of 44%. Simultaneously, a mesh structure optimized by finite element analysis (maximum stress controlled at 140 MPa, pressure drop 0.8 kPa) achieved synergistic optimization of stress distribution and airflow efficiency, thereby improving mechanical stability and airflow distribution efficiency, and significantly enhancing the mechanical stability and conductivity of the SOFC stack. The low resistivity of the Ni-Fe alloy (22 μΩ × cm) enabled the stack to achieve a power density of 0.8 W / cm². 2 Compared to stainless steel fuel cells (0.6W / cm²), 2 The resistivity was increased by 33%, and the area resistivity was reduced to 0.28 μΩ•cm. 2 A complete performance optimization system has been formed, from the intrinsic properties of materials to the structural and functional design.

[0026] In a specific embodiment, the Ni-Fe alloy is prepared by the following method: S101. Mixing Ni powder and Fe powder yields alloy raw materials. After pretreatment, the alloy raw materials are subjected to vacuum melting to obtain alloy ingots.

[0027] Preferably, the preprocessing includes the following steps: The Ni-Fe alloy raw material was pickled in a 5% hydrochloric acid solution for 12 to 20 minutes. The pickled Ni-Fe alloy raw material was placed in deionized water and ultrasonically cleaned at a frequency of 35kHz~40kHz for 15min~20min. After removal, it was dried at 110℃~130℃ for 1.5h~2.5h.

[0028] This application first uses hydrochloric acid to neutralize the oxide layer on the surface of the raw material, thereby dissolving the oxide layer and removing surface scale, oil, and other impurities. This prevents the introduction of non-metallic inclusions during smelting, ensuring the purity of the alloy composition. Next, ultrasonic deep cleaning is used to ensure a pure raw material interface during subsequent smelting, reducing porosity or inclusion defects within the alloy ingot. Finally, heating evaporates the moisture on the raw material surface, preventing the decomposition of water to produce hydrogen gas during smelting and preventing the formation of hydrogen pores during alloy ingot solidification (the solubility of H2 in molten metal decreases with decreasing temperature). This eliminates the influence of moisture on the smelting process and improves the density of the alloy ingot.

[0029] Preferably, the vacuum melting process includes the following steps: Add 0.05wt%~0.15wt% cerium powder and 0.02wt%~0.05wt% yttrium powder, and melt at 1540℃~1560℃ for 40min~50min; after melting, cool to room temperature at a rate of 110℃ / s~120℃ / s under the protection of argon gas.

[0030] In this application, Ce and Y, as rare earth elements, can form high-melting-point compounds (such as Ce₂O₃ and Y₂O₃) with impurities such as S and O in the alloy, thus playing a role in deoxidation and desulfurization. Simultaneously, they can refine the grain size, improve the mechanical properties of the alloy, and make the Ni-Fe solid solution obtained from nickel and iron powder more uniformly distributed, laying the foundation for subsequent performance optimization. Using argon as an inert gas can isolate the melt from air and prevent oxidation. At the same time, rapid cooling (quenching) suppresses the growth of coarse grains, refining the alloy microstructure (the faster the cooling rate, the greater the undercooling, and the higher the nucleation rate), thereby obtaining a fine-grained structure and improving the alloy strength and conductivity of the ingot (the fine-grained structure can reduce grain boundary scattering resistance).

[0031] S102. The alloy ingot is heat-treated to obtain a Ni-Fe alloy.

[0032] In the above scheme, heat treatment can eliminate internal stress, improve alloy toughness, and prevent cracking during thermal cycling; it can also optimize crystal orientation, thereby reducing resistivity; and it can stabilize microstructure, laying the foundation for matching thermal expansion coefficients and electrical conductivity.

[0033] Preferably, the heat treatment temperature is 900℃~980℃, the heat treatment time is 3h~4h, the heat treatment atmosphere is argon, and the cooling rate after heat treatment is 2℃ / min~5℃ / min.

[0034] This application utilizes high-temperature annealing to strengthen and activate alloy atoms, eliminating residual stress from vacuum melting, and simultaneously promoting the uniform precipitation of the second phase (such as the possible formation of Fe-Ni intermetallic compounds in Ni-Fe alloys), thus optimizing lattice distortion. Prolonged holding at high temperature (3-4 hours) allows for further diffusion of the solid solution components, thereby reducing dendrite segregation. Slow cooling (2°C / min to 5°C / min) avoids quenching stress, promotes the formation of an equilibrium microstructure, and prevents abnormal grain growth.

[0035] In the above scheme, the Ni-Fe alloy is pretreated to remove impurities before being used in the vacuum melting process. The pure raw materials combined with rare earth elements can more efficiently purify the melt and avoid inclusions affecting the alloy's density and conductivity. Drying treatment can prevent moisture from being introduced into the pores, and combined with rapid cooling, it further improves the quality of the alloy ingot. The fine-grained solid solution formed by melting is more likely to undergo uniform diffusion during heat treatment. The elimination of residual stress and the precipitation of the second phase are based on the uniform composition after melting. The slow cooling of heat treatment further stabilizes the fine-grained structure during melting, thereby avoiding grain coarsening caused by high-temperature holding, and ultimately achieving a thermal expansion coefficient (11.5 × 10⁻⁶). -6 K -1 The synergistic optimization of thermal compatibility and electrical conductivity (22 μΩ•cm) was achieved. Ultimately, the Ni-Fe alloy achieved a balance in thermal compatibility, electrical conductivity, and mechanical properties, meeting the requirements for SOFC support materials.

[0036] As one embodiment of this application, the Ni-Fe alloy support structure is prepared by powder metallurgy, including the following steps: S301. Prepare Ni-Fe alloy powder with a particle size of 15μm~45μm from Ni-Fe alloy; S302. A grid-like preform is prepared by high-pressure forming; wherein the pressure of high-pressure forming is 250MPa~300MPa.

[0037] High-pressure molding directly presses powder through a mold, eliminating the need for energy-intensive equipment such as laser melting. This results in high raw material utilization (low powder loss) and high production efficiency (batch production is possible with a single pressing). It is particularly suitable for simple, uniformly sized mesh support components, reducing unit product costs.

[0038] As another embodiment of this application, in order to achieve complex precision manufacturing (requiring complex structural design, small batch customization, high-precision surface, or functions that cannot be manufactured by traditional processes, such as internal flow channels and lightweighting), the Ni-Fe alloy support structure is prepared by additive manufacturing, including the following steps: S201. Prepare Ni-Fe alloy powder with a particle size of 15μm~45μm (sphericity >90%).

[0039] Small-particle-size powders have a larger contact area during sintering, resulting in higher diffusion efficiency, but also poorer flowability; while large-particle-size powders have better flowability, they have higher porosity after sintering. Therefore, to balance the requirements of flowability and sintering densification, the particle size of the alloy powder in this application is controlled within the range of 15μm to 45μm. Simultaneously, to improve flowability during powder spreading, spherical powders are used to reduce powder accumulation defects, thereby ensuring interlayer uniformity during SLM forming.

[0040] S202. The Ni-Fe alloy powder is prepared into a mesh-like preform by selective laser melting.

[0041] In a specific embodiment, the laser power of the selective laser melting is 180W~300W, the scanning speed is 700mm / s~900mm / s, and the powder layer thickness is 45μm~55μm.

[0042] Selective laser melting can directly form complex mesh structures without the need for traditional molds, thus shortening the preparation cycle. Furthermore, its forming accuracy reaches ±20μm, meeting the stringent dimensional requirements of SOFC support materials (such as the uniformity of airflow channels).

[0043] S203. The mesh-like preform is sintered in a hydrogen atmosphere at 1300℃~1350℃ for 3h~4h to obtain the desired structure. After sintering, residual powder on the surface is removed by laser cleaning process, and the surface roughness (Ra) is controlled within 0.8μm to finally obtain a high-precision, high-density Ni-Fe alloy support structure.

[0044] Although the preform formed by SLM has a certain density (approximately 30% of the sintered body), it still contains a small amount of porosity, requiring further densification through high-temperature sintering. During sintering, the fine-grained structure formed during SLM (through rapid laser cooling) grows uniformly in a hydrogen atmosphere, while residual porosity is eliminated, ultimately achieving 99% density and simultaneously optimizing electrical conductivity and coefficient of thermal expansion (11.5 × 10⁻⁶). -6 K -1 The sintering temperature is controlled at 1300℃~1350℃, which is the optimal sintering temperature for Ni-Fe alloys (higher than the Ni-Fe eutectic temperature but lower than the melting point of 1455℃). At this temperature, atomic diffusion is active, and pores gradually close through grain boundary migration. Maintaining a holding time of 3h~4h ensures uniform grain growth and avoids residual porosity caused by short-time sintering.

[0045] In a specific embodiment, the single cell includes a Ni-YSZ anode with a thickness of 180μm to 220μm, a YSZ electrolyte with a thickness of 8μm to 12μm, and an LSM cathode with a thickness of 40μm to 60μm; the size of the single cell is 50mm × 50mm.

[0046] The Ni-YSZ (nickel-yttrium stabilized zirconium oxide) anode is a composite material composed of metallic nickel (Ni) and yttrium stabilized zirconium oxide (YSZ). YSZ is a ceramic material obtained by stabilizing zirconium oxide (ZrO2) with yttrium (Y), exhibiting excellent ionic conductivity. It serves as the anode (fuel electrode) in a fuel cell. Ni provides catalytic active sites, promoting the oxidation reaction of fuels (such as hydrogen); YSZ acts as a skeletal support structure and conducts oxygen ions.

[0047] YSZ (yttrium-stabilized zirconium oxide) electrolyte is mainly composed of ZrO2, with a certain amount of Y2O3 (usually 8%~10% molar fraction) incorporated to form a cubic or tetragonal phase structure, exhibiting stable oxygen ion conductivity at high temperatures. The electrolyte is used to isolate fuel from oxidizer, but allows oxygen ions (O2) to pass through. 2- It passes through at high temperatures and is used as a key channel for ion transport in SOFC stacks.

[0048] LSM (Lanium Strontium Manganese Oxide, La) 1-x Sr x The MnO3 cathode is a perovskite-structured composite oxide in which the lanthanum (La) portion is replaced by strontium (Sr), forming a material with good electronic conductivity and catalytic activity. As the cathode (air electrode) of a fuel cell, it catalyzes the reduction of oxygen to generate oxygen ions and conducts electrons.

[0049] Secondly, based on a general inventive concept, this application also discloses a method for preparing a Ni-Fe alloy supported solid oxide fuel cell, comprising the following steps: The single cells are stacked, and an 8μm~12μm thick NiO-YSZ transition layer is screen-printed between the bottom surface of the stacked single cells and the top surface of the Ni-Fe alloy support structure to assemble the fuel cell stack. The fuel cell stack is prepared by pre-sintering at 1050℃~1150℃ for 0.5h~1.5h under a hydrogen-nitrogen mixed gas and a pressure of 4.5kPa~5.5kPa, followed by sintering at 1300℃~1320℃ for 2.5h~3.5h; wherein the volume ratio of hydrogen to nitrogen in the hydrogen-nitrogen mixed gas is 1:8, and the flow rate is 1L / min~3L / min.

[0050] In the above scheme, the composition of the NiO-YSZ transition layer has a certain compatibility with the anode (Ni-YSZ) and the supporting structure (Ni-Fe alloy), which can effectively improve the interfacial bonding strength between the single cell and the Ni-Fe alloy supporting structure, and reduce interfacial cracking caused by factors such as differences in thermal expansion coefficients. The presence of the transition layer can also provide a smoother path for ion and electron transport, reduce interfacial resistance, and thus improve the overall performance of the battery. At the same time, during battery operation, stress will be generated between different material layers due to temperature changes and chemical reactions. The transition layer can play a certain buffering role, improving the structural stability and service life of the stack.

[0051] In the above preparation method, pre-sintering has the following advantages: it allows for preliminary sintering between material particles at a lower temperature, forming a certain sintering neck, improving the initial strength and structural stability of the fuel cell stack, and laying the foundation for subsequent high-temperature sintering. In a hydrogen-nitrogen mixed atmosphere, the pre-sintering process can reduce NiO in the transition layer to Ni, allowing it to better match with the Ni-YSZ structure of the anode, forming a continuous conductive network. Pre-sintering can also remove any volatile impurities or additives that may be present in the material, reducing porosity and defects during the sintering process.

[0052] Sintering offers several advantages: Sintering at higher temperatures allows for further fusion of material particles, resulting in a higher density of the electrolyte layer (YSZ), reducing ion transport resistance, and improving the overall mechanical strength of the battery stack. It also promotes the development of the crystal structure of each functional layer, enhancing their electrochemical performance, such as the ionic conductivity of the YSZ electrolyte and the catalytic activity of the LSM cathode. Furthermore, high-temperature sintering stabilizes the interfaces between layers, forming a better physical and chemical bond, further reducing interfacial resistance and improving battery performance and reliability.

[0053] In the above preparation method, the hydrogen-nitrogen mixture can provide a reducing atmosphere, ensuring the smooth progress of the reduction reaction of the NiO transition layer. Maintaining a certain gas flow rate can also remove volatiles generated during sintering, keeping the furnace atmosphere stable. Appropriate sintering pressure can promote the densification process of the material while preventing deformation or damage to the fuel cell structure due to excessive pressure.

[0054] In a specific embodiment, the preparation method further includes: preparing a 1.5μm~2.5μm thick Al2O3 anti-oxidation coating on the surface of the Ni-Fe alloy support structure by plasma spraying; wherein the plasma spraying power is 30kW and the spraying distance is 100mm. The surface coating with Al2O3 anti-oxidation coating can further improve its high-temperature durability.

[0055] The principles and features of this application are described below with reference to embodiments. The examples are for illustrative purposes only and are not intended to limit the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0056] The instruments used in the embodiments include: Vacuum induction melting furnace, model: VIM-500, vacuum degree 10 -4 Pa.

[0057] X-ray diffractometer, XRD, model: Bruker D8 Advance.

[0058] Scanning electron microscope, SEM, model: Zeiss Sigma 300.

[0059] Thermal expansion meter, NETZSCH DIL 402C.

[0060] Four-probe instrument, Keithley 2635B.

[0061] SLM, Model: EOS M290.

[0062] High-precision electronic balance, model: Mettler Toledo XS205, accuracy 0.001g.

[0063] Ultrasound equipment: Kunshan KQ-500DE, frequency 40kHz.

[0064] Tensile testing equipment: Instron 5982.

[0065] High-precision fixture, model: Custom Precision Jig, alignment accuracy ±10μm.

[0066] Ultrasonic testing equipment: Olympus OmniScan SX, frequency 5MHz.

[0067] Six-axis robot, model: ABB IRB 120, positioning accuracy ±20μm.

[0068] Example 1 This embodiment provides a method for preparing a Ni-Fe alloy supported solid oxide fuel cell, including the following steps: S1. Preparation of Ni-Fe alloy 1) Weigh nickel and iron with a purity ≥ 99.95% as raw materials according to a nickel-iron mass ratio of 35:65, soak them in 5% hydrochloric acid solution for 15 minutes for pickling; after pickling, place them in deionized water for ultrasonic cleaning at a frequency of 40kHz for 20 minutes, take them out and place them in a vacuum oven at 120℃ for 2 hours to dry.

[0069] 2) The dried raw materials were placed in a vacuum induction melting furnace and melted at 1550℃. During the melting process, cerium (0.1wt% of the raw material mass) with a purity ≥99.9% and yttrium were added as trace additives. The mixture was held at this temperature for 45 minutes to ensure uniform composition. After melting, the mixture was rapidly cooled at a rate of 120℃ / s under argon protection to form an alloy ingot with dimensions of 100mm × 50mm × 20mm. The surface of the alloy ingot was mechanically polished (using 2000-grit sandpaper) to remove a 1mm thick defect layer.

[0070] 3) The alloy ingot was annealed for 3.5 h under argon protection (purity 99.999%, flow rate 1 L / min) at 950 °C, and then cooled to room temperature at a rate of 3 °C / min to obtain Ni-Fe alloy.

[0071] X-ray diffraction analysis confirmed that the main phase of the alloy is Ni-Fe solid solution (face-centered cubic structure), with no harmful phases such as Fe3O4 or NiO formed.

[0072] Scanning electron microscopy revealed that the grain size was 10μm~15μm, with clear grain boundaries and no micropores or cracks.

[0073] Tensile testing (equipment: Instron 5982, 800℃, tensile rate 0.5mm / min) showed that the alloy has a yield strength of 225MPa and an elongation of 15%, which meets the mechanical performance requirements of SOFC high-temperature working environment (800℃).

[0074] 4) The performance of the Ni-Fe alloy was tested. First, the coefficient of thermal expansion was measured using a thermal expansion meter when the temperature was increased from room temperature to 1000℃ at a rate of 5℃ / min. The result was 11.5×10⁻⁶. -6 K -1 Deviation ±0.2×10 -6 K -1 This indicates that the Ni-Fe alloy has excellent stability. Figure 2 The relationship between the coefficient of thermal expansion and Ni content was demonstrated, verifying the technical advantages of optimizing Ni and Fe composition in the alloy. Figure 2 In this case, when the Ni content is 35wt%, the coefficient of thermal expansion of the alloy is 11.5×10⁻⁶. -6 K -1 The range of thermal expansion coefficients of SOFC cells (10×10) -6K -1 ~12×10 -6 K -1 , Figure 2 (Represented by the green shaded area) Highly matched. When the Ni content is below 30wt% or above 40wt%, the coefficient of thermal expansion deviates from the matching range of SOFC cells, which may lead to stress concentration during thermal cycling. By quantifying the effect of Ni content on the coefficient of thermal expansion, the technical advantages of Ni-Fe alloy composition optimization were verified, proving that selecting a Ni content of 30wt%~40wt% (optimal 35wt%) can effectively reduce the thermal stress of the stack and improve thermal cycling stability.

[0075] Secondly, the resistivity was measured using the four-probe method with a test current of 100mA, yielding a result of 22 μΩ•cm, which is approximately 70% lower than the 75 μΩ•cm resistivity of traditional stainless steel. Next, a high-temperature oxidation resistance test (800℃, 500 hours in air) showed that the oxide layer thickness on the Ni-Fe alloy surface was 4 μm, with a weight gain of 0.05 mg / cm³. 2 This demonstrates that the Ni-Fe alloy possesses excellent oxidation resistance. Finally, a corrosion resistance test (the test method involves doping the surface with 10 ppm of hydrogen sulfide gas in a hydrogen environment for 200 hours at a temperature of 800℃) proved that no obvious sulfides were formed on the surface of the Ni-Fe alloy, and no sulfur peaks were detected by XPS analysis, indicating that the Ni-Fe alloy has stability in a sulfur-containing environment.

[0076] S2, Optimize the specifications of the support structure 1) Finite element analysis (FEA) and topology optimization were performed using COMSOL Multiphysics 6.0 to design a mesh support structure. The optimization objective was to minimize stress concentration during thermal cycling while ensuring mechanical strength and airflow distribution efficiency. The resulting support structure had a mesh edge length of 2 mm, a mesh thickness of 0.5 mm, an opening ratio of 65%, and a mesh spacing of 4.5 mm. The simulation conditions were as follows: operating temperature 800℃, temperature gradient 5℃ / mm, fuel flow rate 0.5L / min (H2), and oxidant flow rate 2L / min (air).

[0077] FEA results show that the maximum stress of the mesh structure during thermal cycling is 140 MPa, which is 44% lower than the 250 MPa of the traditional plate structure. Computational fluid dynamics (CFD) simulations confirm that the pressure drop is 0.8 kPa, which is 68% lower than the 2.5 kPa of the traditional plate structure, and the fuel and oxidizer concentration deviations are controlled within 5%.

[0078] A 0.25mm radius fillet design can be introduced at the mesh connection points to reduce local stress by 15%. To enhance the strength of high-stress areas (such as the edges of the fuel cell stack), a gradient mesh design is adopted, with the local mesh side length reduced to 1.5mm, resulting in a 20% increase in strength. Figure 1 The geometric design of the grid-like support structure and its integration with SOFC cells are demonstrated. The SOFC cells (green portion) consist of a Ni-YSZ anode, a YSZ electrolyte, and an LSM cathode. The Ni-Fe alloy support structure (gray grid portion) is 0.5 mm thick with an opening ratio of 65%, represented by black grid lines. Through finite element analysis optimization, the grid structure reduces the maximum stress to 140 MPa and the gas flow pressure drop to only 0.8 kPa. The stack comprises multiple layers of cells and support structures stacked alternately. The grid-like support structure not only provides mechanical support but also optimizes the flow channels for fuel (H2 or CH4) and oxidant (air), promoting uniform distribution.

[0079] 2) Crush the Ni-Fe alloy into powder with a particle size of 15μm~45μm and a sphericity >90% (this powder can also be purchased from a supplier, ensuring that the Ni and Fe contents in the alloy powder are 35wt% and 65wt%, respectively). Melt the alloy powder using an SLM (Silicon-Liquid Laser) to obtain a preform (shaped according to the optimized support structure specifications); the SLM melting process uses a laser power of 200W, a scanning speed of 800mm / s, a powder layer thickness of 50μm, and a forming accuracy of ±20μm.

[0080] 3) The preform was sintered at 1320℃ in a hydrogen atmosphere (hydrogen purity 99.999%, flow rate 2L / min) for 3.5 hours until the density reached 99%. Then, residual powder was removed from the surface using a 50W laser cleaning process, controlling the surface roughness to within 0.8μm. The density was verified using the Archimedes method, with an error of <0.5%.

[0081] 4) A 2μm thick Al2O3 anti-oxidation coating is applied to the surface of the grid-like support structure by plasma spraying. The plasma spraying power is 30kW, the spraying distance is 100mm, and the spraying speed is 500mm / s.

[0082] SEM analysis confirmed that the bonding strength between the Al2O3 anti-oxidation coating and the supporting structure was 30 MPa, and the porosity of the coating was <2%. Further high-temperature anti-oxidation testing (under the same conditions as in step S1) confirmed that there was no peeling on the coating surface, the oxide layer thickness was <4 μm, and the weight gain was 0.04 mg / cm³. 2 .

[0083] S3, Assemble the fuel cell stack 1) Single cells were prepared by tape casting and sintering at 1350℃ (sintering atmosphere is air, holding time is 4h). The size of the single cell is 50mm×50mm, the surface flatness error is <20μm, and X-ray CT (resolution 10μm) was used to verify that there are no internal defects.

[0084] The anode is Ni-YSZ with a thickness of 200 μm and a porosity of 30%; the electrolyte is YSZ with a thickness of 10 μm and a density >98%; and the cathode is LSM with a thickness of 50 μm and a porosity of 25%.

[0085] 2) A 10μm thick NiO-YSZ transition layer (NiO:YSZ=1:1) is coated between the support structure and the connected single cell using screen printing technology. The screen mesh is 400 mesh, the printing pressure is 0.2MPa, and the printing speed is 50mm / s.

[0086] During sintering, the transition layer forms Ni-YSZ chemical bonds with an interfacial bonding strength of 50 MPa and a contact resistance of less than 10 mΩ•cm. 2 SEM analysis confirmed that the transition layer was free of cracks, and EDS analysis showed that Ni and Zr elements were uniformly distributed with an interface thickness deviation of <1 μm.

[0087] 3) After stacking 5 layers of single solar cells (totaling 10mm after stacking), a six-axis robot is used to place the stacked solar cells on top of the support structure for rapid alignment. At this point, the transition layer forms an initial bond, and then a high-precision fixture is used for assembly to obtain the solar cell stack.

[0088] The fuel cell stack underwent a second sintering process. The sintering atmosphere was a hydrogen-nitrogen mixture (H2:N2=1:8, flow rate 2L / min), and the sintering pressure was 5 kPa. The first sintering temperature was 1100℃, and the holding time was 1h; the second sintering temperature was 1310℃, and the holding time was 3h.

[0089] Ultrasonic testing at 5MHz confirmed the absence of internal defects in the fuel cell stack. X-ray CT scanning (10μm resolution) verified the geometric accuracy of the mesh structure, with an error of <30μm. Helium leak testing (leakage rate <10%) further confirmed the structure's integrity. -8 Pa•m 3 The sealing performance was confirmed, and the surface roughness (Ra) was controlled within 0.8 μm.

[0090] Experimental Example 1 The performance of the fuel cell stack prepared in Example 1 was tested, including: (1) Thermal cycling stability test like Figure 3As shown, 100 thermal cycles were conducted between room temperature and 800℃ (heating rate 5℃ / min, cooling rate 3℃ / min, high-temperature holding time 30min). The results showed no cracks or interface delamination in the fuel cell stack, and the bonding strength between the cells and the support structure remained stable. SEM analysis (5000× magnification) indicated no microcracks at the interface, a Ni-Fe alloy surface oxide layer thickness of only 3μm, and a weight gain of 0.03mg / cm³. 2 .

[0091] High-temperature creep test (800℃, 1000 hours, load 5MPa, equipment: Instron 5982) showed deformation <0.1%, proving excellent mechanical stability.

[0092] in, Figure 3 The results of thermal cycling stability tests are presented, highlighting the Ni-Fe stack's open-circuit voltage (decreasing from 1.05V to 1.045V, a drop of 0.48%) and power density (from 0.80W / cm²). 2 It dropped to 0.794 W / cm 2 (A decrease of 0.75%). In contrast, the open-circuit voltage (red dashed line, square marker) of the stainless steel fuel cell stack decreased from 1.03V to 0.998V, a decrease of 3.11%; the power density (purple dashed line, diamond marker) decreased from 0.60W / cm². 2 Reduced to 0.559 W / cm 2 The degradation was 6.83%. The excellent performance of the Ni-Fe stack is attributed to the matching of the thermal expansion coefficient of the Ni-Fe alloy with that of the SOFC cell and the stress dispersion capability of the grid-like support structure.

[0093] (2) Electrochemical performance testing The performance was tested at 800℃ using H2 (flow rate 0.5 L / min, purity 99.999%) as fuel and air (flow rate 2 L / min) as oxidant (electrochemical workstation: Gamry Reference 3000). The results are as follows: 1) Open circuit voltage: 1.05V; 2) Maximum power density: 0.8 W / cm³ 2 (Current density 0.8A / cm) 2 ); 3) Aspect-ratio resistivity (ASR): 0.28 Ω•cm 2 It is 0.5 Ω•cm lower than that of traditional stainless steel fuel cell stacks. 2 .

[0094] Electrochemical impedance spectroscopy (EIS, frequency 0.1 Hz–100 kHz, AC amplitude 10 mV) analysis showed an ohmic resistance of 0.15 Ω•cm. 2Polarization resistance 0.13Ω•cm 2 It is superior to the 0.25Ω•cm of stainless steel fuel cell stacks. 2 and 0.20Ω•cm 2 . Figure 4 The electrical performance test results were presented, showing a power density lower than that of traditional stainless steel fuel cell stacks (0.6 W / cm²). 2 The conductivity was improved by 33%, which verified the advantages of the Ni-Fe alloy support structure in terms of electrical conductivity. Figure 4 The paper compares the electrical performance of a Ni-Fe alloy-supported fuel cell stack and a conventional stainless steel-supported fuel cell stack at 800℃ (H2 flow rate 0.5 L / min, air flow rate 2 L / min). The voltage of the Ni-Fe fuel cell stack gradually decreases from the open-circuit voltage of 1.05 V, with a power density of 0.8 A / cm³. 2 It reaches its maximum value of 0.80 W / cm 2 The voltage of the stainless steel fuel cell stack decreased from 1.03V, with a power density of 0.6A / cm². 2 It reaches its maximum value of 0.60 W / cm 2 The power density of Ni-Fe fuel cell stacks is increased by 33%, and the area resistivity (ASR) is reduced from 0.5 Ω•cm in stainless steel stacks. 2 Reduced to 0.28Ω•cm 2 .

[0095] (3) Long-term stability test Operating at a constant temperature of 800℃ for 1000 hours (current density 0.5A / cm²) 2 The voltage decay rate is only 0.7% / 1000 hours, which is better than the industry standard (1.5% / 1000 hours).

[0096] Antioxidant testing (800℃, 500 hours in air, equipment: Thermolyne FD1500) showed that the oxide layer thickness on the alloy surface was 4μm, with a weight gain of 0.04mg / cm³. 2 The coating did not peel off.

[0097] (4) Multi-fuel adaptability test The power density was measured under CH4 (flow rate 0.4 L / min, steam / carbon ratio 2:1) and syngas (CO + H2, flow rate 0.5 L / min, CO:H2 = 1:1) conditions, with a result of 0.74 W / cm³. 2 and 0.77W / cm 2 The ASR values ​​are 0.30 Ω•cm. 2 and 0.29Ω•cm 2 .

[0098] Carbon deposition resistance test (CH4 fuel, 200 hours, 800℃) showed that the carbon deposition on the anode surface was <0.1 mg / cm³.2 EDS analysis did not detect any obvious carbon peaks, demonstrating its durability under complex fuel environments.

[0099] (5) Sulfur poisoning test H2S doped with 10 ppm was run for 200 hours (800℃, current density 0.5 A / cm²). 2 Electrochemical workstation: Gamry Reference 3000; voltage decay <2% (from 0.75V to 0.735V). XPS analysis (equipment: Thermo Fisher ESCALAB 250Xi) confirmed no sulfide deposition on the anode surface, and no sulfur peak was detected in the S2p spectrum, verifying the stack's durability in a sulfur-containing fuel environment. The test was repeated three times, with a voltage decay standard deviation <0.5%, ensuring data reliability.

[0100] (6) Vibration resistance test After 100 hours of operation at a frequency of 10Hz-100Hz and an amplitude of 1mm (vibration table: LDS V850), the fuel cell stack showed no structural damage, the interfacial bonding strength remained at 50MPa, and the power density remained at 0.79W / cm³. 2 The attenuation is <1%.

[0101] (7) Supplementary Explanation Test data was analyzed using a machine learning model (random forest algorithm, Python Scikit-learn library), predicting a decay rate of <7% over 10,000 hours, and R... 2 >0.95.

[0102] Dynamic load test (0.2A / cm) 2 ~0.8A / cm 2 The switching cycle (10 minutes, 100 times) showed that the voltage response time was less than 1 second and the power density fluctuation was less than 2%, verifying the stability of the fuel cell stack under dynamic operating conditions.

[0103] The Ni-Fe alloy-supported MS-SOFC stack prepared in Example 1 achieved thermal expansion matching (11.5 × 10⁻⁶). -6 K -1 ), Improved conductivity (power density 0.8W / cm²) 2 With optimized mechanical stability (maximum stress 140MPa), it exhibits excellent resistance to sulfur poisoning and carbon deposition, providing reliable technical support for the commercial application of SOFC technology.

[0104] Example 2 The difference between this embodiment and Embodiment 1 is that the Ni content in the Ni-Fe alloy is 30wt% and the Fe content is 70wt%, while the other parameters and steps are the same.

[0105] Example 3 The difference between this embodiment and Embodiment 1 is that the Ni content in the Ni-Fe alloy is 40wt% and the Fe content is 60wt%, while the other parameters and steps are the same.

[0106] The coefficients of thermal expansion of the alloys in Examples 2 and 3 were determined to be 11.8 × 10⁻⁶. - 6 K -1 and 11.2×10 -6 K -1 Thermal cycling tests (100 cycles, from room temperature to 800°C) showed that the fuel cell stack of Example 2 exhibited slight interfacial delamination (crack length <50 μm) after 80 cycles. The performance of the fuel cell stack of Example 3 was closer to that of Example 1, but its oxidation resistance was slightly worse than that of Example 1 (oxide layer thickness 6 μm, weight gain 0.07 mg / cm³). 2 Electrical performance tests showed that the power densities of the fuel cells in Examples 2 and 3 were 0.76 W / cm². 2 and 0.78W / cm 2 The ASR values ​​are 0.30 Ω•cm. 2 and 0.29Ω•cm 2 All are lower than those of traditional stainless steel fuel cell stacks (0.5Ω•cm). 2 ).

[0107] Example 4 The only difference between this embodiment and Embodiment 1 is that the number of individual cells in the stack is 10 layers, with a size of 100mm × 100mm and a total thickness of 20mm. The grid of the support structure has a side length of 2.5mm, a thickness of 0.6mm, and an opening ratio of 60%.

[0108] In step S2, the sintering temperature after SLM forming is 1320℃, and the holding time is 4h. In step S3, the second sintering temperature is 1310℃, and the holding time is 3.5h.

[0109] The performance of the large fuel cell stack prepared in Example 4 was tested according to the test method of Example 1, and the results are as follows: (1) Thermal cycling stability test: No cracks, stable interface bonding; (2) Electrochemical performance: Open circuit voltage 1.04V, maximum power density 0.78W / cm³ 2 The ASR is 0.29 Ω•cm 2 ; (3) Long-term stability: 0.8% decay rate per 1000 hours.

[0110] As can be seen from the above, the performance of the large-scale fuel cell stack in Example 4 is significantly better than that of the traditional stainless steel fuel cell stack, verifying the feasibility of the preparation method of this application in large-scale applications.

[0111] In summary, the optimal Ni content in the Ni-Fe alloy of this application is 35 wt%, at which point the coefficient of thermal expansion of the Ni-Fe alloy is optimized to 11.5 × 10⁻⁶. -6 K -1 , with SOFC solar cells (10×10 -6 K -1 ~12×10 -6 K -1 This matching process gives Ni-Fe alloy-supported solid oxide fuel cells the following advantages: (1) Significantly improves thermal cycling stability The fuel cell stack exhibited no cracks or interface delamination during 100 thermal cycles, maintaining stable structural integrity. Scanning electron microscopy (SEM) analysis revealed no microcracks at the interface, and the oxide layer thickness on the alloy surface was only 3 μm. Compared to traditional stainless steel-supported fuel cell stacks (which exhibit microcracks after 50 thermal cycles, with crack lengths >100 μm), the fuel cell stack of this application demonstrates a thermal cycle life more than doubled. Furthermore, the mesh-like support structure, optimized through finite element analysis, reduced the maximum stress to 140 MPa, a 44% reduction compared to the traditional design's 250 MPa. High-temperature creep testing (800℃, 1000 hours, 5 MPa load) showed a deformation of <0.1%, demonstrating its excellent mechanical stability. Figure 3 The thermal cycling stability test results highlight this advantage, significantly improving the reliability of SOFC systems in frequent start-stop scenarios (such as distributed generation with power requirements of 1kW to 100kW).

[0112] (2) Significantly improves electrochemical performance The low resistivity (22 μΩ•cm) of the Ni-Fe alloy enables the fuel cell power density to reach 0.8 W / cm². 2 Compared to traditional stainless steel supported fuel cell stacks (0.6W / cm²), 2 The performance improved by 33%, the open-circuit voltage stabilized at 1.05V, and the area resistance (ASR) decreased to 0.28Ω•cm. 2 Compared to the 0.5Ω•cm of stainless steel fuel cells 2 A 44% reduction. Electrochemical testing (800℃, H2 flow rate 0.5 L / min, air flow rate 2 L / min) showed an electrochemical impedance spectroscopy (EIS) reading of 0.15 Ω•cm. 2 Polarization resistance 0.13Ω•cm 2 Superior to the traditional design of 0.25Ω•cm 2 and 0.20Ω•cm 2 .Figure 4 The electrical performance test results quantified the superior conductivity of the Ni-Fe alloy support structure. Its excellent electrochemical performance improves the energy conversion efficiency of the fuel cell stack, resulting in better output stability under high-load conditions (such as industrial power generation with power requirements >500kW), making it suitable for transportation power systems and stationary power plants.

[0113] (3) Enhance mechanical stability The optimized design of the grid-like support structure significantly reduced stress concentration, with a maximum stress value of only 140 MPa, far lower than the 250 MPa of the traditional plate structure. The open area design, while ensuring mechanical strength, reduced the stack weight by approximately 20% (from 500g in the traditional design to 400g per stack), enabling lightweight design of SOFC systems. Computational fluid dynamics (CFD) simulations optimized the airflow distribution, reducing the pressure drop to 0.8 kPa, a 68% improvement compared to the 2.5 kPa of the traditional plate structure, and increasing fuel utilization efficiency by 10%. Vibration tests (frequency 10Hz~100Hz, amplitude 1mm, 100 hours) showed no structural damage to the stack, and its mechanical stability meets the requirements of complex operating conditions (such as mobile power sources).

[0114] (4) Provides excellent multi-fuel adaptability and durability The fuel cell stack performs well with a variety of fuels: a power density of 0.8 W / cm² under H₂ (0.5 L / min) conditions. 2 0.74 W / cm³ under CH₄ (0.4 L / min, steam / carbon ratio 2:1) conditions. 2 Under syngas conditions (CO + H2, 0.5 L / min, CO:H2 = 1:1), the flow rate is 0.77 W / cm³. 2 This verified its multi-fuel adaptability. Long-term stability testing (800℃, 1000 hours, current density 0.5A / cm²) was conducted. 2 The results showed that the voltage decay rate was only 0.7% / 1000 hours, which is better than the industry standard (1.5% / 1000 hours). Carbon deposition resistance testing (CH4 fuel, 200h) indicated that the carbon deposition on the anode surface was <0.1 mg / cm³. 2 EDS analysis did not detect a significant carbon peak. Sulfur poisoning resistance testing (10 ppm H2S in H2, 200 h) showed a voltage decay of <2%, and XPS analysis confirmed no sulfide deposition. These characteristics make the stack suitable for various energy scenarios, such as biomass gasification (CH4 content >50%) and natural gas power generation (syngas-based), with an expected operating life exceeding 5000 hours.

[0115] (5) Cost-effectiveness and commercialization potential The cost of Ni-Fe alloy raw materials (Ni and Fe) is significantly lower than that of Ni-Cr or Co-based alloys. Powder metallurgy and selective laser melting (SLM) processes are mature and suitable for large-scale production. The lightweight design of the grid structure reduces material usage by 15% (material cost per stack drops from USD 100 in the traditional design to USD 85). The overall manufacturing cost is 15% lower than that of traditional stainless steel stacks, including raw material, processing, and assembly costs. Excellent performance and durability (attenuation rate of 0.7% / 1000 hours) reduce maintenance and replacement frequency, resulting in a 20% reduction in lifecycle costs. Resistance to sulfur poisoning and carbon deposition supports the use of complex fuels, reducing fuel pretreatment costs by 10%. These characteristics provide economic assurance for the commercial application of SOFCs, particularly suitable for distributed energy systems (1kW~100kW) and portable power supplies (weight <5kg), with market potential covering industrial, residential, and mobile sectors.

[0116] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A Ni-Fe alloy supported solid oxide fuel cell, characterized by, The Ni-Fe alloy support structure and the stacked single cell pieces, wherein The Ni-Fe alloy support structure is in a grid shape and is prepared by Ni-Fe alloy powder metallurgy or additive manufacturing; the Ni content of the Ni-Fe alloy support structure is 30wt%-40wt%, and the coefficient of thermal expansion is (11.2-11.8)×10 -6 K -1 ; The grid has a side length of 1.5 mm to 2.5 mm, a thickness of 0.4 mm to 0.6 mm, an opening rate of 50% to 70%, and a grid spacing of 4.0 mm to 5.0 mm.

2. The Ni-Fe alloy supported solid oxide fuel cell according to claim 1, characterized by, The Ni-Fe alloy is prepared by the following method: The Ni-Fe alloy raw material is obtained by mixing Ni powder and Fe powder; After the Ni-Fe alloy raw material is pretreated, vacuum melting treatment is performed to obtain an alloy ingot; The alloy ingot is subjected to heat treatment to obtain the Ni-Fe alloy.

3. The Ni-Fe alloy supported solid oxide fuel cell according to claim 2, characterized in that, The pretreatment includes the following steps: The Ni-Fe alloy raw material is placed in a 5% hydrochloric acid solution for pickling for 12 min to 20 min; The pickled Ni-Fe alloy raw material is placed in deionized water for ultrasonic cleaning at a frequency of 35 kHz to 40 kHz for 15 min to 20 min, and then taken out for drying treatment at 110°C to 130°C for 1.5 h to 2.5 h.

4. The Ni-Fe alloy supported solid oxide fuel cell of claim 2, wherein, The vacuum melting treatment includes the following steps: 0.05wt% to 0.15wt% cerium powder and 0.02wt% to 0.05wt% yttrium powder are added, and melting is performed at a temperature of 1540°C to 1560°C for 40 min to 50 min; After the melting is completed, cooling is performed to room temperature at a rate of 110°C / s to 120°C / s under the protection of argon.

5. The Ni-Fe alloy supported solid oxide fuel cell of claim 2, wherein, The heat treatment has a temperature of 900°C to 980°C, a time of 3 h to 4 h, an atmosphere of argon, and a cooling rate of 2°C / min to 5°C / min.

6. The Ni-Fe alloy supported solid oxide fuel cell of claim 1, wherein, The Ni-Fe alloy support structure is prepared by additive manufacturing, including the following steps: Ni-Fe alloy powder with a particle size of 15 μm to 45 μm is taken, and selective laser melting is performed to prepare a grid-shaped embryo; The grid-shaped embryo is placed in a hydrogen atmosphere and sintered at 1300°C to 1350°C for 3 h to 4 h to obtain the Ni-Fe alloy support structure.

7. The Ni-Fe alloy supported solid oxide fuel cell of claim 6, wherein, The selective laser melting has a laser power of 180 W to 300 W, a scanning speed of 700 mm / s to 900 mm / s, and a powder layer thickness of 45 μm to 55 μm.

8. The Ni-Fe alloy supported solid oxide fuel cell of claim 1, wherein, The single cell piece includes a Ni-YSZ anode with a thickness of 180 μm to 220 μm, a YSZ electrolyte with a thickness of 8 μm to 12 μm, and an LSM cathode with a thickness of 40 μm to 60 μm.

9. The method for producing a Ni-Fe alloy supported solid oxide fuel cell according to any one of claims 1 to 8, characterized by, The single cell piece is stacked, and a NiO-YSZ transition layer with a thickness of 8 μm to 12 μm is applied to the bottom surface of the stacked single cell piece and the top surface of the Ni-Fe alloy support structure by screen printing to obtain an electric pile. The electric pile is pre-sintered at 1050°C to 1150°C for 0.5 h to 1.5 h and sintered at 1300°C to 1320°C for 2.5 h to 3.5 h under the condition of hydrogen-nitrogen mixed gas and a pressure of 4.5 kPa to 5.5 kPa, wherein the volume ratio of hydrogen to nitrogen in the hydrogen-nitrogen mixed gas is 1:

8. The method further includes the following steps:

10. The production method according to claim 9, characterized by, ​ The surface of the Ni-Fe alloy support structure is prepared by plasma spraying to form an Al2O3 oxidation-resistant coating with a thickness of 1.5-2.5 microns; wherein the power of the plasma spraying is 30 kW, and the spraying distance is 100 mm.

Images