Reversible oxygen ion conductor ceramic fuel cell and preparation method thereof

Abstract

The invention relates to a reversible oxygen ion conductor ceramic fuel cell and a preparation method thereof. The preparation method comprises the following steps: providing a Ni-YSZ / YSZ half cell; coating the surface of an electrolyte layer of the half cell with the GDC slurry through a wet spraying process; coating the Yb-doped CaMnO3 perovskite type oxide cathode slurry on the surface of a GDC layer of a half cell through a screen printing process; standing, drying and calcining to obtain a cathode; and carrying out electrode sintering and electrochemical activation treatment to obtain the reversible oxygen ion conductor ceramic fuel cell. The fuel cell cathode is prepared from the cobalt-free strontium-free Yb-doped CaMnO3 perovskite material, so that the problems that the thermal expansion matching property of a traditional cathode is poor, and a high-resistance phase is easily generated on an interface are effectively solved; in cooperation with a casting-co-sintering integrated preparation process, compact forming and tight combination of functional layers of the fuel cell are realized, and interlayer interface compatibility and structural stability are optimized.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more specifically to a reversible oxygen ion conductor ceramic fuel cell and its preparation method. Background Technology

[0002] Solid oxide fuel cells (SOFCs), as a highly efficient green electrochemical power generation device, have become an important development direction in the field of large-scale clean energy utilization due to their outstanding advantages of high energy conversion efficiency and environmental friendliness, and have shown broad application prospects in scenarios such as new energy power generation and distributed energy systems.

[0003] However, the current performance improvement of SOFCs is limited by a core factor: the excessively high polarization resistance of the battery system. Furthermore, polarization resistance exhibits a significant temperature dependence; generally, the lower the temperature, the higher the polarization resistance. This increase in polarization resistance directly leads to a decrease in the oxygen ion transport rate at the cathode and a reduction in the catalytic activity of the oxygen reduction reaction (ORR). Therefore, as the core component of the SOFC electrochemical reaction, the cathode material must simultaneously meet three stringent requirements: first, it must possess high oxygen reduction catalytic activity to improve the core reaction efficiency and reduce polarization resistance; second, it must have sufficient porosity to provide ample physical channels for the transport of oxygen ions and oxygen; and third, it must have good chemical compatibility with adjacent interfaces (GDC, YSZ, SSZ, etc.) such as the electrolyte and barrier layer to avoid interfacial reactions that generate high-resistivity phases, which would further increase the polarization resistance.

[0004] Currently, ABO3-type perovskite oxides are the mainstream materials used in SOFC cathodes, among which cobalt-containing LSCs (La) are the most common. 0.6 Sr 0.4 Perovskite oxides such as CoO3 and LSCF have become high-performance cathode materials with a high degree of commercialization due to their mixed ion electronic conductivity (MIEC). However, these materials have many insurmountable defects, which seriously restrict the industrialization of SOFC.

[0005] On the one hand, in cobalt-containing perovskite oxides, the spin state change of Co leads to a large coefficient of thermal expansion, resulting in poor thermal expansion matching with commonly used YSZ electrolytes. This makes the battery prone to interfacial cracking and delamination during high-temperature operation and thermal cycling, significantly reducing the battery's structural stability and lifespan. On the other hand, these materials exhibit significant A-site element instability; La readily reacts with YSZ electrolytes at the interface, forming La₂Zr₂O₇ and La₄Zr₃O₇. 12The reaction produces a greenish-blue lanthanum phase, while Sr segregates during battery operation, forming impurity phases such as SrO2 and SrCO3. These reaction products and segregated impurities form a high-resistivity layer at the interface, significantly increasing the battery polarization resistance, leading to a decrease in oxygen ion transport rate and ORR activity, ultimately causing a significant decline in SOFC output performance. Furthermore, the high cost of elements such as cobalt and strontium also increases the cost of large-scale SOFC production.

[0006] To address the aforementioned issues, the development of cobalt-free, strontium-free perovskite cathode materials with excellent overall performance has become a key research focus in the SOFC field. CaMnO3 (CMO)-based perovskite oxides, due to their high natural abundance, environmental friendliness, low toxicity, and low preparation cost, have become ideal candidates to replace cobalt- and strontium-containing cathode materials, and their use as an n-type thermoelectric material has been extensively studied. However, original CaMnO3-based materials have inherent defects: low carrier concentration leads to insufficient high-temperature ionic and electronic conductivity, and weak oxygen ion transport capacity; their thermal expansion coefficient is difficult to match with electrolytes such as YSZ, resulting in poor interfacial bonding; furthermore, existing research mainly focuses on their low-temperature performance, with insufficient research on their transport, thermoelectric, and electrochemical behavior at high temperatures, leading to their inability to meet the operational requirements of SOFCs in terms of high-temperature catalytic activity and structural stability.

[0007] Studies have shown that rare-earth element doping modification of CaMnO3 at the Ca sites can effectively control its crystal structure and electronic properties, improve conductivity by introducing charge carriers, and optimize the coefficient of thermal expansion, thereby improving interfacial compatibility with the electrolyte. However, current research on doping modification of CaMnO3-based materials has not yet achieved precise control over the type and proportion of doping elements, making it difficult to simultaneously solve the problems of insufficient ionic conductivity, poor thermal expansion matching, and high interfacial resistance. Furthermore, a suitable fabrication process for SOFC multilayer structures based on modified CaMnO3-based cathode materials has not yet been developed. Consequently, the modified CaMnO3-based materials cannot fully realize their performance advantages and still cannot meet the practical application requirements of high activity and long-term stability in SOFCs. Summary of the Invention

[0008] To address the problems of poor thermal expansion matching, easy formation of high-resistivity phases at the interface, and high cost of existing cobalt-strontium-containing cathode materials in SOFCs, as well as insufficient electrical conductivity and thermal matching, imprecise doping control, and lack of suitable multilayer structure preparation processes for CaMnO3-based materials, this invention aims to provide a reversible oxygen ion conductor ceramic fuel cell and its preparation method.

[0009] The method for preparing a reversible oxygen ion conductor ceramic fuel cell according to the present invention includes the following steps: S1, providing a Ni-YSZ / YSZ half-cell; S2, preparing GDC barrier layer powder, preparing GDC slurry using GDC powder as a base material, coating the GDC slurry onto the electrolyte layer surface of the half-cell using a wet spraying process, and obtaining a Ni-YSZ / YSZ / GDC half-cell after drying and calcination; S3, preparing cobalt-free and strontium-free Yb-doped CaMnO3 perovskite oxide cathode powder, preparing cathode slurry using cathode powder as a base material, and coating the cathode slurry onto the GDC layer surface of the Ni-YSZ / YSZ / GDC half-cell using a screen printing process to form a cathode wet film; S4, subjecting the half-cell substrate with the printed cathode wet film to static stress relief, drying, and calcination treatment to obtain a shaped cathode; S5, subjecting the prepared fuel cell to electrode sintering and electrochemical activation treatment to obtain a reversible oxygen ion conductor ceramic fuel cell.

[0010] In a preferred embodiment, step S1 includes the following sub-steps: S11, preparing a cast film of anode functional layer, anode support layer and electrolyte layer using a casting process, and preparing a casting slurry using corresponding ceramic powder as raw material to obtain a cast film of uniform thickness; S12, assembling the cast film of anode support layer, anode functional layer and electrolyte layer in a layered stack, and improving the density of each layer structure and the interlayer interface bonding degree by isostatic pressing treatment; S13, performing multi-stage heating sintering of the stacked film after isostatic pressing treatment in an air atmosphere to form a dense electrolyte layer and gradient anode structure, thereby obtaining a Ni-YSZ / YSZ half cell.

[0011] In a preferred embodiment, in step S2, cerium source and gadolinium source are used as raw materials, and a complexing agent is dissolved, mixed, heated and stirred to form a gel. The gel is dried and calcined at 220~240℃, sintered at 900~1100℃, and cooled at 2~4℃ / min to obtain GDC powder. The cerium source is cerium nitrate hexahydrate, the gadolinium source is gadolinium nitrate hexahydrate, the complexing agent is citric acid and EDTA, and the dissolving medium is ammonia.

[0012] In a preferred embodiment, in step S2, the GDC slurry is obtained by adding terpineol and carbidol to GDC powder as the base material and dispersing it by ultrasonication; the thickness of the GDC barrier layer film formed by wet spraying is 4~6μm, and the drying and calcination temperature is 1200~1300℃.

[0013] In a preferred embodiment, step S3, the preparation of Yb-doped CaMnO3 perovskite cathode powder, includes: using calcium source, manganese source, and ytterbium source as raw materials, mixing with a complexing agent, heating and stirring to form a gel, and then drying and calcining the gel at 220~240℃, sintering at 900~1100℃, and cooling at 1~3℃ / min to obtain a loose and porous cathode powder; wherein, the calcium source is calcium acetate, the manganese source is manganese acetate, the ytterbium source is ytterbium nitrate hexahydrate, and the complexing agent is citric acid and urea.

[0014] In a preferred embodiment, the chemical formula of the Yb-doped CaMnO3 perovskite cathode powder is Yb x Ca 1-x MnO3, where x is 0.05~0.15.

[0015] In a preferred embodiment, in step S3, the cathode slurry is made by using Yb-doped CaMnO3 cathode powder as the base material, adding terpineol, carbitol, and polyvinyl butyral, along with surfactants and defoamers, and then ball milling it; during the ball milling process, zirconium oxide beads with diameters of 2-4 mm and 4-6 mm are added in a mass ratio of 2:1-4:1, and the ball milling time is 10-14 hours.

[0016] In a preferred embodiment, in step S3, the screen printing uses a 200-300 mesh stainless steel mesh, and the screen is scraped in one direction to form a cathode wet film with a thickness of 10-20 μm.

[0017] In a preferred embodiment, in step S4, the static stress relief time is 20-40 minutes, the low-temperature drying temperature is 120-140℃ and the drying time is 15-25 minutes, the high-temperature calcination heating rate is 1-3℃ / min, the calcination temperature is 900-1100℃, and the holding time is 1-3 hours.

[0018] The reversible oxygen ion conductor ceramic fuel cell obtained by the above preparation method according to the present invention is characterized in that the reversible oxygen ion conductor ceramic fuel cell consists of a cathode, a barrier layer, an electrolyte layer and an anode from top to bottom; the anode includes an anode support layer and an anode functional layer, forming a gradient anode structure.

[0019] This invention utilizes cobalt- and strontium-free Yb-doped CaMnO3 perovskite material to fabricate fuel cell cathodes, effectively improving the problems of poor thermal expansion matching and easy formation of high-resistivity phases at the interface in traditional cobalt- and strontium-containing cathodes. Simultaneously, through precise doping control of rare earth elements, it compensates for the low carrier concentration and insufficient high-temperature conductivity of the original CaMnO3-based material, significantly improving the oxygen reduction catalytic activity and oxygen ion transport efficiency of the cathode, and reducing the polarization resistance of the battery system. This is combined with sol-gel method for powder preparation, wet spraying to form the GDC barrier layer, and screen printing. The cathode process design and the integrated fabrication process of tape casting and co-sintering have enabled the dense forming and tight bonding of each functional layer of the fuel cell, optimized the interlayer interface compatibility and structural stability, and solved the technical pain point of no suitable preparation process for existing modified CaMnO3-based materials. The reversible oxygen ion conductor ceramic fuel cell finally obtained has excellent electrochemical performance, thermal cycling stability and long-term operational reliability. Moreover, the raw material cost is low, the process is highly controllable, and it is suitable for large-scale production requirements, effectively promoting the industrialization of solid oxide fuel cells. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a reversible oxygen ion conductor ceramic fuel cell according to the present invention.

[0021] Figure 2 This is a process flow diagram of the preparation of the reversible oxygen ion conductor ceramic fuel cell according to the present invention.

[0022] Figure 3 yes Figure 1 SEM image and elemental distribution diagram of the cathode of a reversible oxygen ion conductor ceramic fuel cell.

[0023] Figure 4 This is a cross-sectional SEM image of the reversible oxygen ion conductor ceramic fuel cell according to the present invention.

[0024] Figure 5 These are the IV, IP curves and EIS spectra of the cathode material CMO under H2 as fuel conditions.

[0025] Figure 6 It is the cathode material Yb 0.1 IV, IP curves and EIS spectra of CMO under H2 as fuel conditions.

[0026] Figure 7 The curve of constant current stability test results of the reversible oxygen ion conductor ceramic fuel cell according to the present invention under H2 atmosphere for 200 hours.

[0027] Figure 8 This is a physical image of a button from a reversible oxygen ion conductor ceramic fuel cell according to the present invention. Detailed Implementation

[0028] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following embodiments. All simple and equivalent changes and modifications made in accordance with the claims and description of this invention fall within the scope of protection of the claims of this patent. Contents not described in detail herein are conventional technical content.

[0029] This invention discloses a method using cobalt-free and strontium-free Yb 0.1 Ca 0.9 The reversible oxygen ion conductor ceramic fuel cell based on MnO3 perovskite oxygen electrode material and its preparation method are described. The core of this method is to obtain a high-performance cathode by precisely doping CaMnO3 perovskite material with Yb, and to achieve efficient preparation of the multilayer structure of the fuel cell by combining the integrated process of "casting-screen printing-co-sintering". The result is an oxygen ion conductor ceramic fuel cell with excellent electrochemical performance, stable structure and suitable for large-scale preparation.

[0030] like Figure 1 As shown, the reversible oxygen ion conductor ceramic fuel cell according to the present invention comprises, from top to bottom, a cathode, a barrier layer, an electrolyte layer, and an anode. The anode has a gradient anode structure, including an anode support layer and an anode functional layer (AFL). In a preferred embodiment, the cathode is Yb. 0.1 CMO, i.e., Yb 0.1 Ca 0.9 The cathode is MnO3; the barrier layer is GDC; the electrolyte layer is YSZ; and the anode is NiO+YSZ.

[0031] This invention relates to the casting preparation of an anode and an electrolyte layer. In a preferred embodiment, a cast film comprising an anode functional layer, an anode support layer, and an electrolyte layer is prepared using a casting process, with a casting slurry prepared using corresponding ceramic powder as raw material, resulting in a cast film of uniform thickness. In a preferred embodiment, the anode support layer and functional layer are made of NiO-YSZ material, and the electrolyte layer is made of YSZ material. In a preferred embodiment, the casting process parameters include: casting blade height of 25~35μm, substrate heating temperature of 45~55℃, hot air purging temperature of 50~60℃, and casting film tape movement speed of 0.1~0.2cm / s; the resulting cast film thickness includes: anode support layer of 450~550μm, anode functional layer of 15~25μm, and electrolyte layer of 3~5μm.

[0032] This invention includes lamination and isostatic pressing. In a preferred embodiment, the anode support layer, anode functional layer, and electrolyte layer are assembled in a layer-by-layer stack, and isostatic pressing is performed to improve the density of each layer structure and the interlayer interface bonding. In a preferred embodiment, the isostatic pressing pressure is 60~80MPa, the temperature is 60~80℃, and the holding time is 8~12 minutes.

[0033] This invention includes the co-sintering preparation of half-cells. In a preferred embodiment, isostatically pressed laminated films are subjected to multi-stage heating sintering in an air atmosphere to achieve uniform sintering of the metal and ceramic substrates of the anode and electrolyte layers, forming a dense electrolyte layer and a gradient anode structure, thus obtaining a half-cell. In a preferred embodiment, a multi-stage heating strategy is adopted: when the temperature is below 300°C, the heating rate is 0.5~1.5°C / min to remove organic matter; in the 300-1200°C range, the heating rate is 4~6°C / min to ensure uniform sintering; above 1200°C, the heating rate is 0.5~1.5°C / min to ensure dense structural forming, resulting in a Ni-YSZ / YSZ half-cell.

[0034] This invention includes the preparation of GDC barrier layer powder and GDC slurry, and the preparation of the GDC barrier layer by wet spraying. In a preferred embodiment, the GDC barrier layer powder is prepared by sol-gel method; using GDC powder as a base material, terpineol, carbitol and a small amount of dispersant are added, and the mixture is treated by ultrasonic dispersion to obtain GDC slurry; the GDC slurry is coated onto the surface of the sintered half-cell electrolyte layer by wet spraying process to form a GDC barrier layer film, and then dried and calcined to obtain a Ni-YSZ / YSZ / GDC half-cell. Specifically, using cerium source and gadolinium source as raw materials, a complexing agent is dissolved, mixed, heated and stirred to form a gel, the gel is dried and calcined, sintered at high temperature and cooled to obtain GDC powder with high purity and uniform particle size, and GDC slurry is obtained using GDC powder as a base material, and the barrier layer is obtained by spraying the GDC slurry. Figure 2 As shown. In a preferred embodiment, cerium source and gadolinium source are used as raw materials, and a complexing agent is added. The mixture is dissolved, mixed, heated and stirred to form a gel. The gel is dried and calcined at 220~240℃, sintered at 900~1100℃, and cooled at 2~4℃ / min to obtain GDC powder. The cerium source is cerium nitrate hexahydrate, the gadolinium source is gadolinium nitrate hexahydrate, the complexing agent is citric acid and EDTA, and the dissolving medium is ammonia. In a preferred embodiment, the GDC slurry is based on GDC powder, with the addition of terpineol and carbitol, and dispersed by ultrasonication. The thickness of the GDC barrier layer film formed by wet spraying is 1~5μm, and the drying and calcination temperature is 1200~1300℃.

[0035] This invention includes the preparation of Yb-doped CaMnO3 perovskite cathode powder and cathode slurry, and the fabrication of the cathode by screen printing. In a preferred embodiment, Yb-doped CaMnO3 perovskite oxide cathode powder is prepared using a sol-gel method; using the cathode powder as a base material, terpineol, carbitol, and polyvinyl butyral are added, along with a small amount of surfactant and defoamer, to obtain a cathode slurry; the cathode slurry is then coated onto the GDC layer surface of a Ni-YSZ / YSZ / GDC half-cell using a screen printing process to form a wet cathode film. Specifically, calcium, manganese, and ytterbium sources are used as raw materials, mixed with a complexing agent, heated and stirred to form a gel; the gel is then dried, calcined, sintered at high temperature, and cooled to obtain a loose and porous cathode powder; the cathode slurry is obtained using the cathode powder as a base material; and the cathode is obtained by screen printing the cathode slurry. Figure 2 As shown. In a preferred embodiment, calcium, manganese, and ytterbium sources are used as raw materials, and a complexing agent is added. The mixture is then heated and stirred to form a gel. The gel is dried and calcined at 220-240℃, sintered at 900-1100℃, and cooled at a rate of 1-3℃ / min to obtain a loose and porous cathode powder. The calcium source is calcium acetate, the manganese source is manganese acetate, the ytterbium source is ytterbium nitrate hexahydrate, and the complexing agent is citric acid and urea. In a preferred embodiment, the chemical formula of the Yb-doped CaMnO3 perovskite cathode powder is Yb x Ca 1-x MnO3, where x is 0.05~0.15. In a preferred embodiment, the cathode paste is based on Yb-doped CaMnO3 cathode powder, with the addition of terpineol, carbitol, and polyvinyl butyral, along with surfactants and defoamers, and is obtained by ball milling. During ball milling, zirconia beads with diameters of 2~4 mm and 4~6 mm are added in a mass ratio of 2:1~4:1, and the ball milling time is 10~14 hours. In a preferred embodiment, screen printing is performed using a 200~300 mesh stainless steel mesh, with unidirectional printing, resulting in a cathode wet film thickness of 10~20 μm.

[0036] This invention includes cathode drying and calcination. In a preferred embodiment, a half-cell substrate printed with a cathode wet film is subjected to static stress relief, low-temperature drying, and high-temperature calcination to obtain a shaped cathode. In a preferred embodiment, the static stress relief time is 20-40 minutes, the low-temperature drying temperature is 120-140°C and the drying time is 15-25 minutes, the high-temperature calcination heating rate is 1-3°C / min, the calcination temperature is 900-1100°C, and the holding time is 1-3 hours.

[0037] This invention includes the overall activation and assembly of a battery. In a preferred embodiment, the prepared Ni-YSZ / YSZ / GDC / Yb 0.1 Ca 0.9MnO3 fuel cells undergo electrode sintering and electrochemical activation to obtain structurally complete and stable oxygen ion conductor ceramic fuel cells. In a preferred embodiment, the peak power density of the fuel cell is not less than 1.5 W·cm⁻¹ when H₂ is used as fuel. -2 When water vapor is introduced and the voltage is 1.3V, the current density is not less than 1.8A·cm. -2 Furthermore, the voltage showed no significant decay after 200 hours of constant current operation in an H2 atmosphere.

[0038] Thus, this invention adopts an integrated process of "casting-screen printing-co-sintering" to achieve efficient integration and uniform preparation of multi-layer structures for fuel cells. After activation treatment, the battery forms an ideal multi-level gradient electrode structure with tight bonding and uniform structure at each layer interface, thereby improving the overall electrocatalytic activity and stability.

[0039] Example 1

[0040] Both the anode support layer and the anode functional layer are made of NiO-YSZ material, and the electrolyte layer is made of YSZ material. All layers are fabricated using a casting process. During casting, the casting blade height is set to 30 μm, the substrate heating temperature is set to 50℃, the hot air purging temperature is controlled at 55℃, and the casting film belt movement speed is controlled at 0.15 cm / s. By controlling these parameters, a 500 μm thick anode support layer casting film, a 20 μm thick anode functional layer casting film, and a 4 μm thick electrolyte layer casting film were obtained, respectively.

[0041] The prepared anode support layer, anode functional layer and electrolyte layer cast film were assembled in a layer-by-layer manner, and then subjected to isostatic pressing at 70 MPa and 70 °C for 10 minutes to further improve the compactness of each layer structure and the interlayer interface bonding.

[0042] The isostatically pressed laminated membranes were subjected to multi-stage heating and sintering in an air atmosphere. The sintering process parameters included: when the temperature was below 300℃, the heating rate was 1℃ / min to slowly remove the organic components in the slurry and prevent the membrane from blistering or cracking; when the temperature was in the range of 300-1200℃, the heating rate was set to 5℃ / min to ensure uniform sintering of the metal and ceramic substrate and to avoid abnormal particle growth; when the temperature was in the range of 1200-1450℃, the heating rate was reduced to 1℃ / min, and finally, the membrane was held at 1450℃ for 5 hours to form a dense electrolyte layer and a gradient anode structure, thus obtaining the Ni-YSZ / YSZ half-cell.

[0043] In a beaker, 3.91 g of cerium nitrate hexahydrate and 0.45 g of gadolinium nitrate hexahydrate were weighed out by molar ratio and dissolved in 100 ml of deionized water to obtain solution A. 0.4 mol of citric acid (CA) and 0.8 mol of EDTA were weighed out and dissolved in 80 ml of ammonia water, stirred until completely clear to obtain solution B. Solution B was slowly added to solution A, and the mixture was continuously heated and stirred until a homogeneous gel was formed. The gel was placed in an oven and heated at 230 °C for approximately 240 minutes to obtain a fluffy and uniform GDC precursor material. The GDC precursor material was placed in a muffle furnace and sintered at 1000 °C for approximately 6 hours, followed by cooling at a rate of 3 °C / min to finally obtain GDC (Gd). 0.1 Ce 0.9 O2) Barrier layer powder. Weigh 1g of GDC powder, add 15g of terpineol, 0.1g of carbitol, and a small amount of dispersant (ammonium polyacrylate). Disperse the mixture in an ultrasonic disperser for 20min to obtain a uniformly dispersed GDC slurry with suitable viscosity. Take the prepared GDC slurry and coat it onto the electrolyte layer surface of the Ni-YSZ / YSZ half-cell using a wet spraying process to form a GDC barrier layer film with a thickness of about 5μm. Then, dry and calcine it at 1250℃ to obtain the Ni-YSZ / YSZ / GDC half-cell.

[0044] In one beaker, add the following raw materials weighed by molar ratio: 4.77 g calcium acetate, 7.35 g manganese acetate, and 1.347 g ytterbium nitrate hexahydrate. In another beaker, add 38 g citric acid and 8 g urea, and stir thoroughly until completely clear to obtain a complexing agent solution. Mix the above metal salt raw materials with the complexing agent solution, heat and stir for about 6 hours until a stable and homogeneous gel is formed. Place the gel in an oven and heat at 230°C for about 300 minutes to obtain a fluffy and uniform cathode precursor material. Place the cathode precursor material in a muffle furnace and heat to sinter at 1000°C for about 6 hours, then cool at a rate of 2°C / min to finally obtain loose and porous Yb. 0.1 Ca 0.9 MnO3 perovskite cathode powder. Take the prepared Yb 0.1 Ca 0.9 MnO3 cathode powder was mixed with terpineol, carbitol, and polyvinyl butyral in a specific ratio, along with a small amount of surfactant and defoamer. The mixture was then ball-milled in a ball mill jar for 12 hours to obtain a uniformly dispersed cathode slurry with suitable viscosity. A clean and dry Ni-YSZ / YSZ / GDC half-cell substrate was fixed on a screen printing table. Using a 250-mesh stainless steel screen, the prepared cathode slurry was applied and spun in a unidirectional direction under constant pressure to uniformly cover the GDC layer surface of the half-cell, forming a cathode wet film with a wet film thickness of approximately 15 μm.

[0045] The half-cell substrate with the printed cathode wet film was left to stand at room temperature for 30 minutes to eliminate the internal stress generated during the printing process. Then, the substrate was placed in an oven and dried at 130°C for 20 minutes to remove the volatile solvents from the wet film. The dried substrate was then placed in a muffle furnace and heated to 1000°C at a rate of 2°C / min, held at that temperature for 2 hours, and allowed to cool naturally to obtain the formed Yb. 0.1 Ca 0.9 MnO3 cathode.

[0046] The prepared Ni-YSZ / YSZ / GDC / Yb 0.1 Ca 0.9 MnO3 fuel cells undergo electrode sintering and electrochemical activation to obtain structurally complete and stable oxygen ion conductor ceramic fuel cells.

[0047] like Figure 3 As shown, the SEM image of the cathode of the reversible oxygen ion conductor ceramic fuel cell according to the present invention clearly shows Yb 0.1 Ca 0.9 The surface microstructure of the MnO3 perovskite cathode material reveals a loose and porous structure that enhances activity. This structure provides ample reaction sites for the oxygen reduction reaction and facilitates the transport and diffusion of oxygen ions. The elemental distribution diagram visually shows the distribution of core elements such as Ca, Mn, and Yb in the cathode material. The elements are uniformly dispersed without significant segregation, indicating that the cathode material powder prepared by this invention has high purity and good structural uniformity, laying a material foundation for excellent electrochemical performance.

[0048] like Figure 4 As shown in the SEM image of the reversible oxygen ion conductor ceramic fuel cell according to the present invention, the layer boundaries and bonding states of the anode, electrolyte layer, barrier layer and cathode can be clearly observed from the cross-sectional micromorphology. The layers are tightly bonded, without peeling gaps or obvious pore defects, indicating that the preparation process of the present invention can achieve uniform sintering and dense bonding of each functional layer, so that the battery has good thermal stability and mechanical compatibility, and effectively avoids performance degradation caused by poor interlayer bonding.

[0049] Example 2

[0050] Ni-YSZ / YSZ / GDC / Yb prepared in Example 1 0.1 Ca 0.9 Electrochemical performance tests were conducted on MnO3 fuel cells under conditions of 650-800℃, with H2 as fuel and water vapor as operating conditions. Long-term stability and impedance tests were also performed.

[0051] When H2 is used as fuel, the peak power density of the fuel cell reaches 1.83 W·cm³. -2Compared to CaMnO3 cathode fuel cells without Yb doping, the power generation efficiency is significantly improved.

[0052] Under conditions where water vapor is introduced, the fuel cell can achieve a current density of 1.83 A·cm⁻¹ at a voltage of 1.3 V. -2 It exhibits excellent water electrolysis performance.

[0053] like Figure 5 As shown, the voltage of the undoped CMO cathode cell decreases rapidly with increasing current density in power generation mode, and the peak power density is low. The impedance semicircle diameter in the EIS Nyquist plot is large, and the polarization impedance is high. After electrochemical activation, the impedance semicircle diameter of the CMO EC cathode cell is significantly reduced, the polarization impedance is greatly reduced, and the efficiency of interfacial charge transport and oxygen ion transport is effectively improved.

[0054] like Figure 6 As shown, Yb 0.1 The CMO cathode cell exhibits higher output voltage and peak power density in power generation mode, and its current density reaches 1.83 A·cm³ at 1.3V in electrolysis mode. -2 It possesses excellent reversible electrochemical performance; after electrochemical activation, Yb 0.1 The impedance semicircle diameter of the CMO EC cathode cell is further reduced, the polarization impedance is significantly reduced, the interface transport efficiency is greatly improved, and the performance continues to optimize with increasing temperature, with the best performance at 800℃.

[0055] A 200-hour constant current stability test was conducted in an H2 atmosphere. The battery voltage remained stable throughout, with no significant degradation. Compared with the cathode fuel cell without Yb doping, the long-term operational stability was significantly improved.

[0056] like Figure 7 As shown, the curves respectively illustrate the Yb doping at the A-site using the present invention. 0.1 The voltage variation trend of CMO cathode materials and undoped CMO cathode materials. The voltage of undoped Yb cathode materials decreases significantly with increasing operating time, while the voltage of CMO cathode materials using Yb cathode materials... 0.1 After 200 hours of constant current operation, the voltage of the CMO cathode cell remained stable without significant drop, which clearly demonstrates that the cathode material of this invention can significantly improve the long-term operational stability of fuel cells in a hydrogen atmosphere.

[0057] Under H2 conditions, the polarization impedance of the battery is significantly reduced, and the performance degradation rate is greatly reduced. This can be verified by combining the cross-sectional SEM images of the battery. The cathode and the GDC barrier layer are tightly bonded, with no peeling or pore defects, and the battery has good thermal stability and mechanical compatibility.

[0058] Figure 8Yb obtained after complete preparation and calcination process 0.1 The image shows a physical example of a CMO cathode button fuel cell. The cell has a button-like structure, a regular shape, and a dense, crack-free surface. This visually demonstrates that the fabrication process of this invention can achieve the molding and fabrication of fuel cells. Furthermore, the fabricated battery product has a complete structure and uniform appearance, and can be directly used for electrochemical performance testing and practical applications. This provides physical support for the large-scale fabrication and industrialization of this fuel cell.

[0059] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a reversible oxygen ion conductor ceramic fuel cell, characterized in that, The preparation method includes the following steps: S1 provides Ni-YSZ / YSZ half-cells; S2, prepare GDC barrier layer powder, use GDC powder as base material to prepare GDC slurry, coat GDC slurry onto the electrolyte layer surface of half cell by wet spraying process, and obtain Ni-YSZ / YSZ / GDC half cell after drying and calcination treatment. S3. Prepare cobalt-free and strontium-free Yb-doped CaMnO3 perovskite oxide cathode powder, use the cathode powder as a base material to prepare cathode paste, and apply the cathode paste to the GDC layer surface of Ni-YSZ / YSZ / GDC half cell by screen printing process to form a cathode wet film. S4. The half-cell substrate with the printed cathode wet film is subjected to static stress relief, drying, and calcination to obtain the formed cathode. S5. The prepared fuel cell is subjected to electrode sintering and electrochemical activation treatment to obtain a reversible oxygen ion conductor ceramic fuel cell.

2. The preparation method according to claim 1, characterized in that, Step S1 includes the following sub-steps: S11, A cast film consisting of an anode functional layer, an anode support layer, and an electrolyte layer is prepared using a casting process. A casting slurry is prepared using the corresponding ceramic powder as raw material to obtain a cast film with uniform thickness. S12, the anode support layer, anode functional layer and electrolyte layer cast film are assembled in layers according to the hierarchy, and the isostatic pressing treatment is used to improve the density of each layer structure and the bonding degree of the interlayer interface. S13, the isostatically pressed laminated film is sintered in air at multiple stages to form a dense electrolyte layer and a gradient anode structure, thus obtaining a Ni-YSZ / YSZ half cell.

3. The preparation method according to claim 1, characterized in that, In step S2, cerium source and gadolinium source are used as raw materials, and a complexing agent is added to form a gel through dissolution, mixing, heating and stirring. The gel is dried and calcined at 220~240℃, sintered at 900~1100℃, and cooled at 2~4℃ / min to obtain GDC powder. Among them, the cerium source is cerium nitrate hexahydrate, the gadolinium source is gadolinium nitrate hexahydrate, the complexing agent is citric acid and EDTA, and the dissolving medium is ammonia water.

4. The preparation method according to claim 3, characterized in that, In step S2, the GDC slurry is made by using GDC powder as a base material, adding terpineol and carbitol, and dispersing it by ultrasonication; the thickness of the GDC barrier layer film formed by wet spraying is 4~6μm, and the drying and calcination temperature is 1200~1300℃.

5. The preparation method according to claim 1, characterized in that, In step S3, the preparation of Yb-doped CaMnO3 perovskite cathode powder includes: using calcium source, manganese source, and ytterbium source as raw materials, mixing with a complexing agent, heating and stirring to form a gel, drying and calcining the gel at 220~240℃, sintering at 900~1100℃, and cooling at 1~3℃ / min to obtain loose and porous cathode powder; wherein, the calcium source is calcium acetate, the manganese source is manganese acetate, the ytterbium source is ytterbium nitrate hexahydrate, and the complexing agent is citric acid and urea.

6. The preparation method according to claim 5, characterized in that, The chemical formula of the Yb-doped CaMnO3 perovskite cathode powder is Yb x Ca 1-x MnO3, where x is 0.05~0.

15.

7. The preparation method according to claim 5, characterized in that, In step S3, the cathode slurry is made by using Yb-doped CaMnO3 cathode powder as the base material, adding terpineol, carbitol, and polyvinyl butyral, along with surfactants and defoamers, and then ball milling it. During the ball milling process, zirconium oxide beads with diameters of 2-4 mm and 4-6 mm are added in a mass ratio of 2:1-4:1, and the ball milling time is 10-14 hours.

8. The preparation method according to claim 1, characterized in that, In step S3, the screen printing uses a 200-300 mesh stainless steel mesh and is scraped in one direction to form a cathode wet film with a thickness of 10-20 μm.

9. The preparation method according to claim 1, characterized in that, In step S4, the static stress relief time is 20-40 minutes, the low-temperature drying temperature is 120-140℃ and the drying time is 15-25 minutes, the high-temperature calcination heating rate is 1-3℃ / min, the calcination temperature is 900-1100℃, and the holding time is 1-3 hours.

10. The reversible oxygen ion conductor ceramic fuel cell obtained by the preparation method according to any one of claims 1-9, characterized in that, The reversible oxygen ion conductor ceramic fuel cell consists of a cathode, a barrier layer, an electrolyte layer, and an anode from top to bottom; the anode includes an anode support layer and an anode functional layer, forming a gradient anode structure.

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