A-site high-entropy solid oxide fuel cell cathode material as well as preparation method and application thereof

Abstract

The invention discloses an A-site high-entropy solid oxide fuel cell cathode material as well as a preparation method and application thereof, and provides an A-site high-entropy solid oxide fuel cell cathode material Pr < 0.2 > M < 0.2 > La < 0.2 > Ba < 0.2 > Sr < 0.2 > Co < 0.8 > Fe < 0.2 > O < 3-delta > with a perovskite phase. The preparation method comprises the following steps: S1, weighing multi-element metal nitrates, and mixing to obtain a first mixed solution; s2, dissolving ethylenediamine tetraacetic acid in ammonia water to obtain a second mixed solution; mixing the first mixed solution, the second mixed solution and citric acid to form a mixed precursor solution; s3, carrying out second heating treatment on the mixed precursor solution, and adjusting the pH value to form a gel precursor; and S4, carrying out pre-sintering treatment, third heat treatment and calcination treatment on the gel precursor to obtain a high-grade powder precursor, and carrying out ball milling and sieving treatment to obtain the A-site high-entropy solid oxide fuel cell cathode material. The cathode material is high in stability and good in chemical compatibility with a barrier layer GDC, provides high-quality mass transfer channels and active sites for O2 / O- / O2-, and has good electrochemical performance at medium and low temperatures.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide fuel cells, and in particular to an A-site high-entropy solid oxide fuel cell cathode material, a preparation method thereof, and applications thereof. Background Art

[0002] Solid oxide fuel cells (SOFCs) have the advantages of high power generation efficiency, strong fuel adaptability, and recoverable high-temperature waste heat. They have broad application prospects in large-scale power generation, distributed power generation and combined heat and power, transportation, peak-shaving energy storage and other fields.

[0003] However, at high temperatures (800–1000°C), electrodes in conventional solid oxide fuel cells (SOFCs) are susceptible to sintering, leading to reactions at the electrolyte-electrode interface (e.g., Sr diffusion). Furthermore, conventional SOFCs have long startup times, high-temperature sealant and interconnect material costs, and poor thermal cycling stability, further limiting their development. At low to moderate temperatures (500–800°C), cathode catalytic activity declines due to a significant decrease in oxygen reduction reaction (ORR) kinetics and insufficient adaptability of the material's physicochemical properties. At low to moderate temperatures, the adsorption of oxygen molecules on the cathode surface weakens, and the dissociation process into oxygen atoms requires higher energy, increasing the activation energy for the ORR and significantly reducing the reaction rate. Furthermore, at low to moderate temperatures, the intrinsic performance of cathode materials exhibits limitations, such as decreased electronic and ionic conductivity and structural instability. This leads to a series of technical challenges, including a reduction in oxygen vacancy concentration, reduced electron-oxygen ion cotransfer efficiency, and a significant increase in the polarization resistance (ASR).

[0004] High-entropy perovskite (HEP) has been widely studied in many fields. High-entropy perovskite refers to the A site (such as La3 + 、Sr2 + ) or B position (such as Co 3+ 、Fe 3+ 、Ni 2 +) Introduce 5 or more metal elements in nearly equimolar ratios to form a highly disordered solid solution structure. High-entropy materials composed of multiple elements have extremely high mixing entropy and can form a stable single solid solution phase, making the high-entropy perovskite structure highly stable. The multivalent state characteristics of the high-entropy A site facilitate the formation of continuous oxygen vacancy channels, regulate oxygen vacancies and enhance ORR activity. Therefore, there is an urgent need to develop a new type of solid oxide fuel cell high-entropy perovskite (HEP) cathode material that is stable, reliable and has excellent electrochemical performance at medium and low temperatures to solve the technical problems existing in traditional SOFCs. Summary of the Invention

[0005] The present invention discloses an A-site high entropy solid oxide fuel cell cathode material and its preparation method and application, and provides an A-site high entropy solid oxide fuel cell cathode material Pr with a perovskite phase. 0.2 M 0.2 La 0.2 Ba 0.2 Sr 0.2 Co 0.8 Fe 0.2 O 3-δ The high entropy perovskite structure enhances the stability of the perovskite material and improves the chemical compatibility with the GDC barrier layer in the battery. The cathode material presents porous coral-like aggregates, providing high-quality mass transfer channels (O2 / O - / O 2- ) and active sites, and has good electrochemical performance at medium and low temperatures.

[0006] The first object of the present invention is to provide an A-site high entropy solid oxide fuel cell cathode material, the cathode material molecular formula is Pr 0.2 M 0.2 La 0.2 Ba 0.2 Sr 0.2 Co 0.8 Fe 0.2 O 3-δ , where M is Sm or Gd and δ is an oxygen vacancy.

[0007] The second object of the present invention is to provide a method for preparing the above-mentioned A-site high entropy solid oxide fuel cell cathode material, the method comprising:

[0008] S1: Weigh metal nitrates of Pr, M, La, Ba, Sr, Co, and Fe respectively and place them in a beaker. Add deionized water to the beaker, stir evenly, and then perform a first heating treatment to obtain a first mixed solution.

[0009] S2 dissolving ethylenediaminetetraacetic acid in aqueous ammonia to obtain a second mixed solution; mixing the first mixed solution, the second mixed solution, and citric acid and stirring them uniformly to form a mixed precursor solution;

[0010] S3: placing the mixed precursor solution in a water bath for a second heating treatment, and adjusting the pH value of the mixed precursor solution to form a gel precursor;

[0011] S4: placing the gel precursor in an electric heating mantle for pre-sintering treatment to obtain a primary powder precursor; then placing the powder precursor in a muffle furnace for a third heat treatment and calcining treatment in sequence to obtain a high-grade powder precursor;

[0012] S5 then ball-mills and sieves the advanced powder precursor to obtain the A-site high entropy solid oxide fuel cell cathode material Pr 0.2 M 0.2 La 0.2 Ba 0.2 Sr 0.2 Co 0.8 Fe 0.2 O 3-δ .

[0013] Specifically, the molar ratio of Pr, M, La, Ba, Sr, Co and Fe in the cathode material in step S1 is 1:1:1:1:1:4:1.

[0014] Specifically, the metal nitrates of Pr, La, Ba, Sr, Co and Fe are Pr(NO3)3·6H2O, La(NO3)3·6H2O, Ba(NO3)2, Sr(NO3)2, Co(NO3)2·6H2O and Fe(NO3)3·9H2O respectively; the metal nitrate of M is Sm(NO3)3·6H2O or Gd(NO3)3.

[0015] Specifically, the temperature of the first heating treatment in step S1 is 30-35°C.

[0016] Specifically, the molar ratio of metal cations, ethylenediaminetetraacetic acid and citric acid in the mixed precursor solution in step S2 is 1:1:1.5.

[0017] Specifically, in step S3, the temperature of the second heating treatment is 80° C., and the time is 6 to 8 hours; and the pH value of the mixed precursor solution is adjusted to 8.

[0018] Specifically, the temperature of the pre-calcination treatment in step S4 is 250° C., and the time is 0.5 to 1 hour.

[0019] Specifically, the temperature of the third heating treatment is 500-600° C., and the time is 1-2 hours; the temperature of the calcination treatment is 1000° C., and the time is 4-6 hours.

[0020] The third object of the present invention is to provide an application of the above-mentioned cathode material in a solid oxide fuel cell.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] (1) The A-site high entropy solid oxide fuel cell cathode material Pr with a perovskite phase prepared by the present invention 0.2 M 0.2 La 0.2 Ba 0.2 Sr 0.2 Co0.8 Fe 0.2 O 3-δ After doping the metal elements Pr, M (M = Gd / Sm), La, Ba, and Sr at the A-site, the five elements form a high-entropy material in equal atomic proportions. Due to the lattice distortion effect caused by the five atoms, the cathode material is an electron-ion mixed conductor with good conductivity. The similar ionic radii and small size differences of the five A-site elements favor the formation of a stable single-phase structure, suppressing the separation of secondary phases when a single element is present, and enhancing the stability of the perovskite material. While maintaining their respective advantages, they also exert a synergistic effect. The multivalent nature of the entropic A-site can influence the formation of continuous oxygen vacancy channels, widen the active sites, regulate oxygen vacancies, and enhance oxygen reduction reaction activity.

[0023] (2) In the present invention, M is Gd or Sm. Gd exists in a +3 valence form in high-entropy perovskites, while Sm exists in +2 and +3 valence forms. Selecting Gd or Sm is beneficial for promoting the formation of oxygen vacancies or affecting the valence state of B-site elements, thereby affecting oxygen ion and electron conductivity, optimizing oxygen adsorption / dissociation kinetics, and enhancing ORR activity. In addition, Sm has a larger atomic radius than Gd, and mixing with the other four A-site elements causes a high entropy effect, resulting in a wider distribution of A / B-site ion radii. By adjusting local strain, the average Goldschmidt tolerance factor approaches 1, suppressing phase separation, and thus improving the structural stability of the cathode material.

[0024] (3) The cathode material prepared by the present invention can simultaneously transmit oxygen ions and electrons, which can effectively reduce the polarization resistance of the cathode of the oxygen ion conductive solid oxide fuel cell, improve the current density of the fuel cell, and maintain good structural stability in an air atmosphere, which can effectively enhance the output stability of the battery. At the same time, it also improves the barrier layer Ce in the battery. 0.9 Gd 0.1 O 2-δ (GDC) chemical compatibility, the cathode material presents porous coral-like aggregates, providing excellent mass transfer channels (O2 / O - / O 2- ) and active sites, and has good electrochemical performance at medium and low temperatures.

[0025] (4) The cathode material provided by the present invention has ionic conductivity brought about by the synergistic effect of high entropy elements, and abundant oxygen vacancies are more conducive to the formation of oxygen ions O 2-The migration of oxygen and the surface exchange and bulk diffusion of oxygen contribute to the excellent electrochemical performance of solid oxide fuel cells at medium and low temperatures. The Pr element at the A site is an alkaline earth metal, which maintains structural stability and effectively inhibits Sr / Ba segregation. The doping of the M element creates abundant oxygen vacancies, which can reduce polarization resistance in the medium and low temperature range of 600–800°C, especially improve electronic conductivity, promote charge transfer, and enhance oxygen adsorption / dissociation. La stabilizes the ABO3 lattice and provides a basic oxygen ion conduction path. Ba and Sr synergistically expand the lattice, reduce the oxygen vacancy formation energy, enhance oxygen ion conductivity, and improve the CO2 tolerance of the cathode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 XRD comparison diagram of the A-site high entropy solid oxide fuel cell cathode materials prepared in Examples 1 and 2 of the present invention;

[0027] Figure 2 This is the XRD pattern of the GDC powder prepared in Example 1 of the present invention;

[0028] Figure 3 XRD comparison chart of chemical compatibility between A-site high entropy solid oxide fuel cell cathode material and GDC powder prepared in Examples 1 and 2 of the present invention;

[0029] Figure 4 This is a SEM image of the A-site high entropy solid oxide fuel cell cathode material PGLBSCF prepared in Example 1 of the present invention;

[0030] Figure 5 (a) is a SEM image of the A-site high entropy solid oxide fuel cell cathode material PSLBSCF prepared in Example 2 of the present invention;

[0031] Figure 5 (b) is a partially enlarged SEM image of the A-site high entropy solid oxide fuel cell cathode material PSLBSCF prepared in Example 2 of the present invention;

[0032] Figure 6 This is an XPS comparison chart of the A-site high entropy solid oxide fuel cell cathode materials prepared in Examples 1 and 2 of the present invention;

[0033] Figure 7 (a) O1s deconvolution diagram of the A-site high entropy solid oxide fuel cell cathode material PGLBSCF prepared in Example 1 of the present invention;

[0034] Figure 7 (b) O1s deconvolution diagram of the A-site high entropy solid oxide fuel cell cathode material PSLBSCF prepared in Example 1 of the present invention;

[0035] Figure 8(a) is a comparison chart of the impedance of the solid oxide fuel cell prepared in Example 1 of the present invention at different test temperatures;

[0036] Figure 8 (b) is a comparison chart of the impedance of the solid oxide fuel cell prepared in Example 2 of the present invention at different test temperatures;

[0037] Figure 8 (c) is a comparison chart of the power output performance of the solid oxide fuel cell prepared in Example 1 of the present invention at different test temperatures;

[0038] Figure 8 (d) is a comparison chart of the power output performance of the solid oxide fuel cell prepared in Example 2 of the present invention at different test temperatures. Specific implementation plan

[0039] The following will combine the contents in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not used to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items. It should be understood that, unless otherwise specified, the various raw materials in the present invention can be obtained commercially.

[0040] Example 1

[0041] Preparation of cathode materials

[0042] S1: Pr(NO3)3·6H2O, Gd(NO3)3, La(NO3)3·6H2O, Ba(NO3)2, Sr(NO3)2, Co(NO3)2·6H2O, and Fe(NO3)3·9H2O weighed in sequence in a molar ratio of 1:1:1:1:1:4:1 are placed in a beaker, deionized water is added to the beaker, and stirred to dissolve them in the deionized water, followed by a first heat treatment at 35°C for 0.5h to obtain a first mixed solution a;

[0043] S2: dissolving ethylenediaminetetraacetic acid (EDTA) in ammonia water (NH3·H2O) to obtain a second mixed solution a; mixing the first mixed solution a, the second mixed solution a, and citric acid (CA) to form a mixed precursor solution a, wherein the molar ratio of metal cations, ethylenediaminetetraacetic acid, and citric acid in the mixed precursor solution a is controlled to be 1:1:1.5;

[0044] S3: placing the mixed precursor solution a in a water bath at 80° C. for a second heating treatment for 6 h, and adjusting the pH value of the mixed precursor solution to 8 to form a gel precursor a;

[0045] S4: placing the gel precursor a in an electric heating mantle and pre-calcining it at 250°C for 0.5h to obtain a primary powder precursor a; then placing the powder precursor a in a muffle furnace and heating it from room temperature to 600°C at 1°C / min for a third heat treatment for 1.5h to decompose nitrates and organic matter; then heating it from 600°C to 1000°C at 5°C / min for calcining it for 4h to obtain an advanced powder precursor a;

[0046] S5 ball milled the advanced powder precursor a at 600 rpm for 5 h and sieved it with a 300 mesh sieve to obtain the A-site high entropy solid oxide fuel cell cathode material Pr 0.2 Gd 0.2 La 0.2 Ba 0.2 Sr 0.2 Co 0.8 Fe 0.2 O 3-δ , denoted as PGLBSCF.

[0047] Preparation of solid oxide fuel cells

[0048] The solid oxide fuel cell structure is: anode layer NiO-YSZ | electrolyte layer YSZ | barrier layer GDC | cathode layer HEP. The single cell was purchased from Xuzhou Huaqing Jingkun Energy Co., Ltd. and has a structure of anode layer NiO-YSZ (anode support) | electrolyte layer YSZ.

[0049] Ce(NO3)3·6H2O (99.95%) and Gd(NO3)3 were mixed in a molar ratio of 9:1 and dissolved in deionized water. Glycine (metal ion / glycine) was added under stirring.

[0050] =1mol / 1.5mol), after forming a transparent sol, it was heated and concentrated to form a brown gel, and continued to heat until it ignited. The collected light yellow powder was calcined at 900℃ for 2h to obtain the barrier layer Ce 0.9 Gd 0.1 O 2-δ (GDC) powder;

[0051] The cathode material PGLBSCF and the binder were mixed in an agate mortar at a weight ratio of 1:1 and ground thoroughly with stirring for 2 hours to obtain a cathode slurry. GDC powder and the binder were mixed in a weight ratio of 1:1 to obtain a GDC slurry. The binder was a 6 wt% ethyl cellulose solution in terpineol.

[0052] The GDC slurry was evenly coated on the cathode side of the solid electrolyte layer YSZ by screen printing, dried on an electric heating mantle at about 100°C for 10 minutes, and then placed in a muffle furnace for calcination at 1000°C for 2 hours to form a barrier layer GDC. The cathode slurry was evenly coated on the GDC barrier layer by screen printing, dried on an electric heating mantle at 100°C for 10 minutes; the above steps were repeated three times, and then placed in a muffle furnace for calcination at 1000°C for 2 hours to form a 0.5 cm thick barrier layer. 2 Effective area of ​​cathode layer HEP;

[0053] Conductive porous silver paste was screen-printed on the entire anode side of the electrolyte, while conductive porous silver paste was screen-printed on only the effective area of ​​the cathode side. The electrolyte was dried on an electric heating sleeve at 120°C for 15 minutes. After that, silver wire was welded to the cathode side (using sealed silver paste), and then placed in a muffle furnace and steadily heated to 600°C and calcined for 1 hour. After being removed from the muffle furnace, the exposed sealing silver paste was covered with a sealing high-temperature adhesive to ensure airtightness. At the same time, it was wrapped around the cathode. It was sealed twice and allowed to stand for 2 hours to obtain the solid oxide fuel cell a prepared in Example 1. The cathode material in this solid oxide fuel cell a was PGLBSCF.

[0054] Example 2

[0055] Preparation of cathode materials

[0056] S1: Pr(NO3)3·6H2O, Sm(NO3)3·6H2O, La(NO3)3·6H2O, Ba(NO3)2, Sr(NO3)2, Co(NO3)2·6H2O, and Fe(NO3)3·9H2O weighed in sequence in a molar ratio of 1:1:1:1:1:4:1 are placed in a beaker, deionized water is added to the beaker, and stirred to dissolve them in the deionized water, followed by a first heat treatment at 35°C for 0.5h to obtain a first mixed solution b;

[0057] S2 dissolves EDTA in ammonia water NH3·H2O to obtain a second mixed solution b; the first mixed solution b, the second mixed solution b and CA are mixed and stirred to form a mixed precursor solution b, and the molar ratio of metal cations, EDTA and CA in the mixed precursor solution b is controlled to be 1:1:1.5;

[0058] S3: placing the mixed precursor solution b in a water bath at 80° C. for a second heating treatment for 8 h, and adjusting the pH value of the mixed precursor solution to 8 to form a gel precursor b;

[0059] S4: placing the gel precursor b in an electric heating mantle and pre-calcining it at 250°C for 1 hour to obtain a primary powder precursor b; then placing the powder precursor b in a muffle furnace and heating it from room temperature to 500°C at 1°C / min for a third heat treatment for 2 hours, and then heating it from 500°C to 100°C at 5°C / min for calcining it for 6 hours to obtain an advanced powder precursor b;

[0060] S5 ball milled the advanced powder precursor b at 600 rpm for 5 h and sieved it with a 300 mesh sieve to obtain the A-site high entropy solid oxide fuel cell cathode material Pr 0.2 Sm 0.2 La 0.2 Ba 0.2 Sr 0.2 Co 0.8 Fe 0.2 O 3-δ , denoted as PSLBSCF.

[0061] Preparation of solid oxide fuel cells

[0062] The preparation method is the same as that in Example 1, except that the cathode material in the solid oxide fuel cell b is PSLBSCF.

[0063] Structural characterization

[0064] (5) In order to determine whether the cathode material prepared in Example 1-2 forms a single phase, XRD test was performed on the cathode powder at room temperature. Figure 1 The XRD comparison diagram of the A-site high entropy solid oxide fuel cell cathode material prepared in Examples 1 and 2 of the present invention; Figure 1 As shown, both PGLBSCF and PSLBSCF cathode powders exhibit a stable perovskite structure without impurities, and both belong to the cubic Pm-3m (221) space group with lattice parameters of This indicates that all five metal atoms are well coupled to the A site. High-entropy materials composed of five elements in equal atomic ratios can form a stable single solid solution phase, suppressing the separation of secondary phases when the five elements are separated. While maintaining their respective strengths, they also work synergistically to broaden the active site. The multivalent nature of the entropic A site can influence the formation of continuous oxygen vacancy channels, enabling oxygen vacancy regulation and enhancing oxygen reduction reaction activity.

[0065] To verify the chemical compatibility of cathode materials with GDC powder, the barrier layer in solid oxide fuel cells, PGLBSCF and PSLBSCF cathode powders were mixed with GDC powder at a mass ratio of 1:1, and the ground mixture was calcined at 1000℃ for 3h. Figure 2 and Figure 3 , Figure 2 This is the XRD pattern of the GDC powder prepared in Example 1 of the present invention; Figure 3 The XRD comparison diagram of the chemical compatibility of the A-site high entropy solid oxide fuel cell cathode material and GDC powder prepared in Examples 1 and 2 of the present invention; Figure 3 As shown in the figure, the XRD spectra of the mixed samples all maintain their independent components, with no new diffraction peaks appearing and no diffraction peak position shifting, which indicates that the polar material and GDC powder do not react at 1000°C, showing good chemical compatibility.

[0066] Figure 4 This is a SEM image of the A-site high entropy solid oxide fuel cell cathode material PGLBSCF prepared in Example 1 of the present invention; Figure 5 (a) is a SEM image of the A-site high entropy solid oxide fuel cell cathode material PSLBSCF prepared in Example 2 of the present invention; Figure 5 (b) is a partially enlarged SEM image of the A-site high entropy solid oxide fuel cell cathode material PSLBSCF prepared in Example 2 of the present invention; as shown in the figure, the two cathode materials have similar morphologies but slightly different sizes. Both are similar to highly porous coral-like aggregates, with O2 / O - / O 2- Provides high-quality mass transfer channels and active sites.

[0067] In the examples of the present invention, XPS technology is used to identify the valence of elements and the relative amounts in the structure. Figure 6 and Figure 7 Shown are the XPS spectra of the two cathode powders, compared by deconvolution of the O1s spectra of the two samples. Figure 6 This is an XPS comparison chart of the A-site high entropy solid oxide fuel cell cathode materials prepared in Examples 1 and 2 of the present invention; Figure 7 (a) O1s deconvolution diagram of the A-site high entropy solid oxide fuel cell cathode material PGLBSCF prepared in Example 1 of the present invention; Figure 7 (b) is the O1s deconvolution diagram of the A-site high entropy solid oxide fuel cell cathode material PSLBSCF prepared in Example 1 of the present invention; as shown in the figure, it is found that PSLBSCF has richer oxygen vacancy content, adsorbed oxygen species and lattice oxygen (O2 2- / O - :O lat ) is more prominent, indicating that it is more conducive to oxygen ions O 2The migration of Sm and the surface exchange and bulk diffusion of oxygen further enhance cathode activity. In high-entropy perovskite cathodes, Sm has a richer atomic radius than Gd, and mixing with the other four A-site elements induces a high-entropy effect, leading to a wider distribution of A / B-site ion radii. Local strain regulation allows the average tolerance factor to approach 1, suppressing phase separation and achieving high structural stability. Gd exists in high-entropy perovskites in a +3 valence form, while Sm exists in +2 and +3 valence forms. The lower valence state promotes the formation of oxygen vacancies or affects the valence state of B-site elements, further affecting oxygen ion and electron conductivity, optimizing oxygen adsorption / dissociation kinetics, and enhancing ORR activity.

[0068] Performance Testing

[0069] The solid oxide fuel cells prepared in Examples 1 and 2 were electrochemically tested using wet H2 (3% H2O) as the fuel gas and air as the oxidizing gas at a test temperature range of 600-750°C. Figure 8 (a) is a comparison chart of the impedance of the solid oxide fuel cell prepared in Example 1 of the present invention at different test temperatures; Figure 8 (b) is a comparison chart of the impedance of the solid oxide fuel cell prepared in Example 2 of the present invention at different test temperatures; Figure 8 (c) is a comparison chart of the power output performance of the solid oxide fuel cell prepared in Example 1 of the present invention at different test temperatures; Figure 8 (d) is a comparison chart of the power output performance of the solid oxide fuel cell prepared in Example 2 of the present invention at different test temperatures. As shown in the figure, at the test temperature, the open circuit voltage (OCV) of the two single cells is close to the theoretical value of 1.1V, indicating that there are no cracks in the battery. For the solid oxide fuel cell a with PGLBSCF as the cathode material in Example 1, the maximum power density of the single cell at 650, 700 and 750°C is 0.238, 0.472 and 0.767 W / cm, respectively. 2 At 750℃, Rp is 0.531Ω·cm 2 For the solid oxide fuel cell b using PSLBSCF as the cathode material in Example 2, the maximum power density of the battery reached 0.329, 0.612 and 0.935 W / cm at 650, 700 and 750°C, respectively. 2 At 750℃, Rp is only 0.428Ω·cm 2Both have good electrochemical properties at medium and low temperatures; compared with PGLBSCF, the PSLBSCF cathode in Example 2 has a finer grain and porous structure. At the same time, the ionic conductivity brought by the synergistic effect of high-entropy elements and the abundant oxygen vacancies are more conducive to the migration of oxygen ions and the surface exchange and bulk diffusion of oxygen, and are well connected with the GDC layer. The YSZ is dense enough to separate the oxidizing and reducing atmospheres, thereby improving the electrochemical performance of the battery.

[0070] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An A-site high entropy solid oxide fuel cell cathode material, characterized in that: The cathode material molecular formula is Pr 0.2 M 0.2 La 0.2 Ba 0.2 Sr 0.2 Co 0.8 Fe 0.2 O 3-δ , where M is Sm or Gd and δ is an oxygen vacancy.

2. A method for preparing a cathode material according to claim 1, characterized in that: The method comprises: S1: Weigh metal nitrates of Pr, M, La, Ba, Sr, Co, and Fe respectively and place them in a beaker. Add deionized water to the beaker, stir evenly, and then perform a first heating treatment to obtain a first mixed solution. S2: dissolving ethylenediaminetetraacetic acid in aqueous ammonia to obtain a second mixed solution; and mixing the first mixed solution, the second mixed solution, and citric acid to form a mixed precursor solution. S3: placing the mixed precursor solution in a water bath for a second heating treatment, and adjusting the pH value of the mixed precursor solution to form a gel precursor; S4: placing the gel precursor in an electric heating mantle for pre-sintering treatment to obtain a primary powder precursor; then placing the powder precursor in a muffle furnace for a third heat treatment and calcining treatment in sequence to obtain a high-grade powder precursor; S5 then ball-mills and sieves the advanced powder precursor to obtain the A-site high entropy solid oxide fuel cell cathode material Pr 0.2 M 0.2 La 0.2 Ba 0.2 Sr 0.2 Co 0.8 Fe 0.2 O 3-δ .

3. The method for preparing a cathode material according to claim 2, wherein: The molar ratio of Pr, M, La, Ba, Sr, Co and Fe in the cathode material in step S1 is 1:1:1:1:1:4:

1.

4. The method for preparing a cathode material according to claim 2, wherein: The metal nitrates of Pr, La, Ba, Sr, Co and Fe in step S1 are Pr(NO3)3·6H2O, La(NO3)3·6H2O, Ba(NO3)2, Sr(NO3)2, Co(NO3)2·6H2O and Fe(NO3)3·9H2O respectively; the metal nitrate of M is Sm(NO3)3·6H2O or Gd(NO3)3.

5. The method for preparing a cathode material according to claim 2, wherein: The temperature of the first heating treatment in the step S1 is 30-35°C.

6. The method for preparing a cathode material according to claim 2, wherein: The molar ratio of metal cations, ethylenediaminetetraacetic acid and citric acid in the mixed precursor solution in step S2 is 1:1:1.

5.

7. The preparation method according to claim 2, characterized in that In the step S3, the temperature of the second heating treatment is 80° C. and the time is 6 to 8 hours; and the pH value of the mixed precursor solution is adjusted to 8.

8. The preparation method according to claim 2, characterized in that The temperature of the pre-calcination treatment in step S4 is 250° C. and the time is 0.5 to 1 hour.

9. The preparation method according to claim 2, characterized in that The temperature of the third heating treatment in step S4 is 500-600° C., and the time is 1-2 hours; the temperature of the calcination treatment is 1000° C., and the time is 4-6 hours.

10. Use of a cathode material prepared by the preparation method according to claims 2 to 9 in a solid oxide fuel cell.

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