LSCF material based on gel-assisted solid-phase reaction method and preparation method

Abstract

The invention provides a preparation method of an LSCF material based on a gel-assisted solid-phase reaction method, which comprises the following steps: on the basis of the solid-phase reaction method, applying low-cost raw materials such as oxide and carbonate, adding sodium alginate as a main gel component, and mixing and ball-milling the raw materials; after long-time ball milling, the slurry is added into a low-concentration Sr < 2 + > solution to rapidly form gel, the traditional advantages of a solid phase method and the uniformity of a wet chemical method are combined by utilizing a gel network confinement effect, and the method is suitable for large-scale production and preparation of SOFC cathode materials, oxygen permeable membranes and other key materials.

Description

Technical Field

[0001] The present invention relates to the field of cathode materials, and in particular to a method for preparing LSCF materials based on a gel-assisted solid phase reaction method. Background Art

[0002] Solid oxide fuel cells (SOFCs) directly convert fuel chemical energy into electricity through electrochemical reactions, unconstrained by the Carnot cycle. Single-unit power generation efficiencies reach 45%-60%, and combined heat and power (CHP) efficiency can be increased to 80%-90%. SOFCs are compatible with a variety of fuels, including hydrogen, natural gas, biomass gas, and coal-to-gas. They can even process fuels containing impurities (such as CO and sulfur), reducing reliance on pure hydrogen and demonstrating strong compatibility with existing energy systems.

[0003] The solid oxide electrolyzer (SOEC) is a highly efficient energy conversion device based on high-temperature water electrolysis to produce hydrogen. Its core principle is to decompose water vapor into hydrogen and oxygen under high-temperature conditions through the synergistic effect of electrical energy and thermal energy. The system efficiency far exceeds that of traditional alkaline electrolysis (AWE) and proton exchange membrane electrolysis (PEM) technologies. Secondly, the scalability of raw materials gives it unique potential in the fields of carbon capture and synthetic fuel production. In addition, the reversibility of SOEC and SOFC enables them to be used as chemical energy storage devices to achieve flexible conversion between electricity and hydrogen energy.

[0004] The cathode / oxygen electrode is an important component of SOFC / SOEC and is the main site for redox reactions. The cathode impedance can account for 70% of the total polarization impedance of the battery, so the performance of the cathode plays a decisive role in battery performance. 1-x Sr x Co y Fe 1-y O 3-δ ) As one of the most mainstream cathodes currently used in SOFC, it has excellent ion-electron mixed conductivity, redox activity, and high oxygen surface exchange coefficient and self-diffusion coefficient.

[0005] Currently, the main methods for synthesizing LSCF are the glycine combustion method, the sol-gel method, and the solid-phase reaction method. The glycine combustion method and the sol-gel method can produce nanoparticles with relatively uniform particle size and composition, and exhibit good performance, but they require stringent synthesis conditions and are difficult to synthesize on a large scale. The solid-phase reaction method is low-cost and suitable for large-scale synthesis. However, due to the large number of LSCF components and the large variation in raw material properties, the solid-phase reaction method is prone to component stratification and segregation during the preparation process, and is prone to hard agglomeration, resulting in LSCF with inferior performance compared to the first two methods.

[0006] The glycine combustion method, disclosed in CN201110428338.3 and CN202310949538.6, primarily uses four nitrate components as raw materials. These are dissolved in deionized water along with glycine, then heated to volatilize the solvent, forming a viscous colloid. Further heating causes the colloid to spontaneously ignite, forming the desired precursor. This precursor is then calcined to produce the finished LSCF. This method uses relatively expensive nitrates, and the release of nitrogen oxides during glycine combustion has environmental impacts. Furthermore, the intense reaction can lead to localized excessive temperatures, which can volatilize Sr and result in uneven composition. Strictly controlled conditions are required, and the rapid exothermic nature of the combustion reaction can lead to variations in grain size and phase composition between batches, making it difficult to meet the consistency requirements of industrial production.

[0007] The sol-gel method disclosed in CN202411066928.X mainly uses soluble salts of four components as the main raw materials (usually nitrates), adds a chelating agent to form a sol under certain temperature conditions, continuously heats to form a gel, and then prepares the LSCF finished product after drying and calcination. The process is similar to the glycine combustion method, and both can obtain LSCF powder with small and uniform particle size. However, the disadvantages are also similar to those of the glycine combustion method. The cost and conditions (temperature, pH, etc.) are strict, making it difficult to apply on a large scale.

[0008] The solid-phase reaction method uses four oxide or carbonate components as raw materials, ball-milling them in a solvent to obtain a direct precursor, which is then calcined to produce the final LSCF product. This method offers low raw material costs, a simple process, and requires no rigorous experimental conditions, making it the preferred method for large-scale powder preparation. However, due to the large variability in raw material properties, the large-scale preparation process using the solid-phase reaction method is prone to stratification and segregation due to differences in density and particle size among the components. This results in an uneven composition and impure crystal phase in the final material, affecting electrochemical properties (such as conductivity and oxygen reduction activity). Summary of the Invention

[0009] The purpose of the present invention is to provide a method for preparing LSCF materials based on a gel-assisted solid-phase reaction method.

[0010] To achieve the object of the present invention, the present invention provides a method for preparing LSCF material based on a gel-assisted solid phase reaction method, comprising the following steps: (1) Using oxides or carbonates of lanthanum, strontium, cobalt, and iron as raw materials, adding an appropriate amount of gel material, and ball milling and mixing in a solvent to obtain a precursor slurry; (2) Mix the precursor slurry with low concentration Sr 2+ The solution is mixed to make the gel material and Sr 2+ Ionic cross-linking occurs to form a three-dimensional network gel, which sinks to the bottom of the solution; (3) Collecting the three-dimensional network gel, rinsing and drying it to obtain a xerogel; (4) The dry gel is calcined at high temperature and then ground to obtain LSCF powder.

[0011] Furthermore, the gel material in step (1) is sodium alginate.

[0012] Preferably, the amount of sodium alginate added is 0.25-2% by mass of the raw material. If the concentration of sodium alginate is lower than 0.25%, it is difficult to form a gel, and if the concentration of sodium alginate is higher than 2%, the slurry viscosity is too high to be fully ball-milled.

[0013] Furthermore, the solvent in step (1) is deionized water.

[0014] Furthermore, in step (2) Sr 2+ The concentration of the solution is 0.1-0.5 mol / L.

[0015] The Sr 2+ The solution may be strontium chloride solution, strontium nitrate solution or strontium acetate solution, and preferably strontium chloride solution.

[0016] Furthermore, the three-dimensional network gel of step (3) is dried at 80-120° C. for 3-6 hours.

[0017] Furthermore, the conditions for high-temperature calcination in step (4) are: 800-1200° C. for 2-8 hours.

[0018] Furthermore, an appropriate amount of dispersant is added during the ball milling process in step (1); the dispersant is selected from at least one of polyethylene glycol, citric acid, polyvinyl pyrrolidone, dodecylbenzene sulfonic acid, etc., preferably polyethylene glycol.

[0019] In a specific embodiment of the present invention, the preparation method comprises the following steps: 1) Lanthanum oxide, strontium carbonate, cobalt oxide, and iron oxide are weighed in a stoichiometric ratio and placed in a ball mill as raw materials. Deionized water (equivalent in mass to the raw materials), 0.25-2% sodium alginate (by mass percentage of the raw materials), and 0.25-1.5% (preferably 0.5%) polyethylene glycol (by mass percentage of the raw materials) are then added to the ball mill and ball milled for 10-24 hours to form a uniform precursor slurry. 2) Add the precursor slurry to a 0.1-0.5 mol / L strontium chloride solution and let it stand for 0.5-2 hours to obtain a three-dimensional network gel; 3) Filter out the three-dimensional network gel, rinse with deionized water, and then dry at 80-120°C to obtain a xerogel; 4) The dry gel is calcined at 800-1200°C for 2-8 hours and then ground to obtain LSCF powder.

[0020] By means of the above technical solution, the present invention has at least the following advantages and beneficial effects: The present invention is based on the solid phase reaction method, uses low-cost raw materials such as oxides and carbonates, and adds sodium alginate as the main gel component. The raw materials are mixed and ball milled; after a long period of ball milling, the slurry is added to a low concentration of Sr 2+ A gel is formed rapidly in the solution, and the gel network confinement effect is utilized to combine the traditional advantages of the solid-phase method with the uniformity of the wet chemical method. It is suitable for the large-scale production of key materials such as SOFC cathode materials and oxygen permeable membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a process flow chart in a specific embodiment of the present invention.

[0022] Figure 2 The following are XRD patterns of materials prepared in various embodiments and comparative examples of the present invention.

[0023] Figure 3 These are microscopic morphologies of materials prepared in various embodiments and comparative examples of the present invention; A, B, C, and D respectively represent morphologies of materials prepared in embodiments 1-4, and E, F, and G respectively represent morphologies of materials prepared in comparative examples 1-3.

[0024] Figure 4 Figures 1 and 2 show the power density test results of the materials prepared in the embodiments and comparative examples of the present invention; Figures A, B, C, and D respectively represent the power density test results of batteries made from the materials prepared in Examples 1-4, and Figures E, F, and G respectively represent the power density test results of batteries made from the materials prepared in Comparative Examples 1-3. DETAILED DESCRIPTION

[0025] In the traditional solid phase method, when the raw materials are mechanically mixed, gravity sedimentation or diffusion segregation is likely to occur during the drying and calcination process due to differences in particle density and size, resulting in uneven composition. 2+ Crosslinking forms a three-dimensional porous gel skeleton, anchoring the oxide particles within the grid and physically blocking particle migration. The carboxylic acid groups in the gel electrostatically adsorb metal cations, promoting ion diffusion during calcination, lowering the solid-phase reaction activation energy (calcination temperature), and minimizing local compositional deviations. Compared to the sol-gel method and glycine combustion method, this method directly uses inexpensive oxides and carbonates as raw materials, resulting in a significantly lower raw material cost than nitrates. The preparation process is relatively simple, making reaction conditions more easily controlled.

[0026] The present invention adopts the following technical solutions: The present invention provides a preparation process of LSCF material based on gel-assisted solid-phase reaction method, comprising: 1. Raw material pretreatment: Weigh La2O3, SrCO3, Fe2O3, CoO and other raw materials according to the stoichiometric ratio; add sodium alginate (the amount of sodium alginate added accounts for 0.25-2% of the mass percentage of the raw materials), and mix by wet ball milling for 10-24 hours to form a uniform precursor slurry.

[0027] 2. Gelation fixation: The precursor slurry is added to a low concentration (0.1-0.5 mol / L) strontium chloride solution (or strontium nitrate, strontium acetate), sodium alginate and Sr 2+ Ionic cross-linking occurs, wrapping the oxide particles to form a three-dimensional network gel, which sinks to the bottom of the solution and is allowed to stand for 0.5-2 hours to complete solidification. The gel is filtered out and the surface of the gel is rinsed.

[0028] 3. Drying: The gel is dried at 80-120°C to remove free moisture.

[0029] 4. High temperature calcination: 800-1200℃ for 2-8 hours to complete the synthesis of LSCF perovskite phase.

[0030] The above process flow is shown in Figure 1 .

[0031] The present invention also screened the gel material and optimized its dosage: During the experiment, two other gel materials, gelatin and acrylamide, were used in addition to sodium alginate. However, gelatin gels slowly, collapses during drying, and differs from the method described in the present invention. Acrylamide is a complex process requiring the addition of an initiator, and acrylamide itself is highly toxic. Ultimately, sodium alginate was chosen as the primary gel component.

[0032] During the experiment, it was found that when the concentration of sodium alginate was higher than 2%, the slurry viscosity was too high to be ball-milled, and when it was lower than 0.25%, it was difficult to form a gel.

[0033] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.

[0034] The polyethylene glycol used in the following examples was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., with a molecular weight of 5000.

[0035] Example 1 Preparation process of LSCF material based on gel-assisted solid phase reaction method According to LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O3-δ ) Lanthanum oxide, strontium carbonate, cobalt oxide and iron oxide were weighed in a stoichiometric ratio and placed in a ball mill as raw materials. Deionized water of equal mass to the raw materials, 0.75% of sodium alginate by mass of the raw materials and 0.5% of polyethylene glycol by mass of the raw materials were added as dispersants into the ball mill for ball milling. After 24 hours, the slurry was poured into a 0.2 mol / L strontium chloride aqueous solution and allowed to stand for 30 minutes. The slurry formed a gel and sank to the bottom of the solution. The slurry was filtered out with a sieve, rinsed with deionized water and dried at 90°C to obtain a dry gel. The dry gel was placed in a muffle furnace and calcined at 1000°C for 3 hours. After grinding, LSCF powder was obtained.

[0036] Example 2 Preparation process of LSCF material based on gel-assisted solid phase reaction method According to LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ) Lanthanum oxide, strontium carbonate, cobalt oxide and iron oxide were weighed in a stoichiometric ratio and placed in a ball mill as raw materials. Deionized water of the same mass as the raw materials, 1% sodium alginate and 0.5% polyethylene glycol as dispersants were added to the ball mill for ball milling. After 24 hours, the slurry was poured into a 0.2 mol / L strontium chloride aqueous solution and allowed to stand for 30 minutes. The slurry formed a gel and sank to the bottom of the solution. The slurry was filtered out with a sieve, rinsed with deionized water and dried at 90°C to obtain a dry gel. The dry gel was placed in a muffle furnace and calcined at 1000°C for 3 hours. After grinding, LSCF powder was obtained.

[0037] Example 3 Preparation process of LSCF material based on gel-assisted solid phase reaction method According to LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ) Lanthanum oxide, strontium carbonate, cobalt oxide and iron oxide were weighed in a stoichiometric ratio and placed in a ball mill as raw materials. Deionized water of the same mass as the raw materials, 0.75% of sodium alginate and 0.5% of polyethylene glycol as dispersants were added to the ball mill for ball milling. After 24 hours, the slurry was poured into a 0.2 mol / L strontium chloride aqueous solution and allowed to stand for 30 minutes. The slurry formed a gel and sank to the bottom of the solution. The slurry was filtered out with a sieve, rinsed with deionized water and dried at 90°C to obtain a dry gel. The dry gel was placed in a muffle furnace and calcined at 1100°C for 3 hours. After grinding, LSCF powder was obtained.

[0038] Example 4 Preparation process of LSCF material based on gel-assisted solid phase reaction method According to LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ) Lanthanum oxide, strontium carbonate, cobalt oxide and iron oxide were weighed in a stoichiometric ratio and placed in a ball mill as raw materials. Deionized water of the same mass as the raw materials and sodium alginate accounting for 0.75% of the mass of the raw materials were added to the ball mill for ball milling. After 24 hours, the slurry was poured into a 0.2 mol / L strontium chloride aqueous solution and allowed to stand (30 minutes). The slurry formed a gel and sank to the bottom of the solution. The slurry was filtered out with a sieve, rinsed with deionized water and dried at 90°C to obtain a dry gel. The dry gel was placed in a muffle furnace and calcined at 1000°C for 3 hours. After grinding, LSCF powder was obtained.

[0039] Comparative Example 1 (conventional solid phase reaction method): According to LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ) Lanthanum oxide, strontium carbonate, cobalt oxide and iron oxide were weighed in a stoichiometric ratio and placed in a ball mill as raw materials. Deionized water of the same mass as the raw materials and polyethylene glycol (0.5% by mass of the raw materials) were added as a dispersant to the ball mill for ball milling. After 24 hours, the slurry was dried at 90°C and calcined in a muffle furnace at 1000°C for 3 hours. LSCF powder was obtained after grinding.

[0040] Comparative Example 2 (conventional solid phase reaction method): According to LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ) Lanthanum oxide, strontium carbonate, cobalt oxide and iron oxide were weighed in a stoichiometric ratio and placed in a ball mill as raw materials. Deionized water of the same mass as the raw materials and polyethylene glycol (0.5% by mass of the raw materials) were added as a dispersant to the ball mill for ball milling. After 24 hours, the slurry was dried at 90°C and calcined in a muffle furnace at 1200°C for 3 hours. LSCF powder was obtained after grinding.

[0041] Comparative Example 3 (sol-gel method): According to LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δLanthanum nitrate, strontium nitrate, cobalt nitrate, and ferric nitrate were weighed in stoichiometric proportions and completely dissolved in deionized water (total metal ion concentration was 0.4 mol / L). The pH of the mixed solution was adjusted to 5-6. Citric acid (1.5 times the total amount of metal ions) was then added to the mixed solution until completely dissolved. The beaker containing the mixed solution was placed in a thermostatic water bath at 80°C with continuous stirring to obtain a wet gel. The wet gel was transferred to a thermostatic drying oven at 180°C and vacuum-dried to obtain a dry gel. The dry gel was then ground into a fine powder and sintered at 1000°C for 3 hours to obtain LSCF nanoparticle powder.

[0042] Experimental example: 1. XRD (X-ray diffractometer) Figure 2 The following is a phase analysis diagram of the LSCF material. XRD results show that the LSCF prepared by the gel-assisted solid-phase method can obtain a pure perovskite structure under calcination conditions of 1000°C and 1100°C. However, the conventional solid-phase method has obvious impurity peaks after calcination at 1000°C. The impurity peak represents strontium carbonate. A relatively pure phase can only be obtained after the temperature is raised to 1200°C. The gel-assisted LSCF has a sharper peak shape and a smaller half-height width, indicating higher crystallinity and a lower calcination temperature. It is not much different from the LSCF prepared by the normal sol-gel method. The test results of the gel-assisted solid-phase method in the absence of dispersant show a weak impurity peak at around 30°. The reason may be that the hard agglomerates are encapsulated during the gelation process. The components of the hard agglomerates are inherently uneven, resulting in a small amount of raw materials not undergoing solid-phase reaction and forming impurity peaks.

[0043] 2. SEM (Scanning Electron Microscope) Figure 3 SEM results show that the particles produced by the gel-assisted solid-phase method at 1000°C are fine and uniform, with primary particle sizes of approximately 200-400 nm and no apparent agglomeration. The particle size of samples with higher sodium alginate concentrations is slightly higher than that of samples with lower concentrations, and the particle size changes little when the calcination temperature is increased to 1100°C. The morphology of samples without dispersant shows that the particles are cubic and larger than those of the sample with dispersant (Example 1). LSCF powder prepared by the conventional solid-phase method also has a primary particle size of approximately 300-500 nm, but exhibits significant agglomeration. The agglomerated particles of the sample calcined at 1200°C reach a size of approximately 5 μm.

[0044] 3. Battery polarization impedance Electrochemical impedance spectroscopy was performed using an electrochemical workstation, scanning from 0.01 Hz to 1 MHz at open circuit potential, and the portion between two locations where the imaginary part of the impedance spectrum was 0 was intercepted for analysis.

[0045] Impedance is an important parameter that reflects the conductivity and redox activity of the material itself. At the test temperature, the ohmic impedance mainly comes from the electrolyte, but it can still reflect the cathode conductivity and sintering state. Polarization impedance is a key parameter for measuring the electrode reaction kinetics and material transfer efficiency, which directly determines the energy conversion efficiency of the battery. The materials prepared in the above examples and comparative examples were screen-printed on the same half-cell according to the same method to make a full cell, and the electrochemical performance test was carried out. The results in Table 1 show that the polarization impedances of Example 1, Example 2 and Comparative Example 3 are relatively low. The polarization impedance of Example 2 is slightly higher than that of Example 1, but the ohmic impedance is lower, indicating that its sintering activity may be better, while the impedances of Comparative Examples 1 and 2 are higher. The higher polarization impedance of Example 4 may be due to the presence of a small amount of impurities and the increase in particle size that reduces the sintering activity, but the gel-assisted effect makes its polarization impedance still lower than that of the ordinary solid-phase method.

[0046] Table 1

[0047] 4. Power density Linear sweep voltammetry was performed using an electrochemical workstation. The potential was controlled to change from the open circuit potential of the battery to 0 V (relative equilibrium potential) and the corresponding current was recorded. The power density was calculated using the formula power density P = E (potential) × I (current) / S (working area).

[0048] The power density of solid oxide fuel cells (SOFCs) is one of the core indicators for measuring their performance. It represents the electric power output per unit area or unit volume of the battery, and directly reflects the energy conversion efficiency and practical application potential. Figure 4 The test results show that the power density of the samples prepared by the gel-assisted method is not much different from that of the sol-gel method. The power density of the sol-gel method (Comparative Example 3) is 1.14W / cm 2 , and the test results of the three gel-assisted LSCFs were 1.03W / cm 2 , 1.13W / cm 2 and 1.05W / cm 2 Combined with the impedance comparison, the reason may be that the sintering activity of Example 2 is slightly better, while the power density of the samples prepared by the conventional solid phase reaction method (Comparative Examples 1 and 2) is only 0.849 W / cm 2 and 0.900W / cm 2 The maximum power density of Example 4 is 0.994W / cm 2 , which shows the influence of dispersant on particle morphology and particle size, which directly affects the performance.

[0049] In summary, the LSCF powder prepared by the gel-assisted solid-phase reaction method in the present invention has the characteristics of low cost and suitability for large-scale preparation of the solid-phase reaction method. It also alleviates the problem of uneven composition of the solid-phase method through a simple gel method and reduces the calcination temperature. The electrochemical test results also show that its impedance and power density reach similar levels to those of the sol-gel method.

[0050] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for preparing LSCF material based on gel-assisted solid phase reaction method, characterized in that: The following steps are involved: (1) Using oxides or carbonates of lanthanum, strontium, cobalt, and iron as raw materials, adding an appropriate amount of gel material, and ball milling and mixing in a solvent to obtain a precursor slurry; (2) Mix the precursor slurry with low concentration Sr 2+ The solution is mixed to make the gel material and Sr 2+ Ionic cross-linking occurs to form a three-dimensional network gel, which sinks to the bottom of the solution; (3) Collecting the three-dimensional network gel, rinsing and drying it to obtain a xerogel; (4) The dry gel is calcined at high temperature and then ground to obtain LSCF powder.

2. The method according to claim 1, characterized in that The gel material in step (1) is sodium alginate.

3. The method according to claim 2, characterized in that The addition amount of sodium alginate is 0.25-2% of the mass percentage of the raw material.

4. The method according to claim 1, wherein The solvent in step (1) is deionized water.

5. The method according to claim 1, wherein Step (2) Sr 2+ The concentration of the solution is 0.1-0.5 mol / L; The Sr 2+ The solution is strontium chloride solution, strontium nitrate solution or strontium acetate solution.

6. The method according to claim 1, wherein The three-dimensional network gel of step (3) is dried at 80-120° C. for 3-6 hours.

7. The method according to claim 1, characterized in that The conditions for high-temperature calcination in step (4) are: 800-1200°C for 2-8 hours.

8. The method according to any one of claims 1 to 7, characterized in that Step (1) adding an appropriate amount of dispersant during ball milling; Wherein, the dispersant is selected from at least one of polyethylene glycol, citric acid, polyvinyl pyrrolidone and dodecylbenzene sulfonic acid.

9. The method according to claim 8, characterized in that The following steps are involved: 1) Lanthanum oxide, strontium carbonate, cobalt oxide, and iron oxide are weighed in a stoichiometric ratio and placed in a ball mill as raw materials. Deionized water (equal in mass to the raw materials), 0.25-2% sodium alginate (mass percentage of the raw materials), and 0.25-1.5% polyethylene glycol (mass percentage of the raw materials) are then added to the ball mill and ball milled for 10-24 hours to form a uniform precursor slurry. 2) Add the precursor slurry to a 0.1-0.5 mol / L strontium chloride solution and let it stand for 0.5-2 hours to obtain a three-dimensional network gel; 3) Filter out the three-dimensional network gel, rinse with deionized water, and then dry at 80-120°C to obtain a xerogel; 4) The dry gel is calcined at 800-1200°C for 2-8 hours and then ground to obtain LSCF powder.

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