A high-entropy perovskite cathode material, its preparation method and application

Abstract

The present invention discloses a high-entropy perovskite cathode material, a preparation method thereof and an application thereof, belonging to the technical field of electrochemical materials. The cathode material in the present invention is an ABO3-type high-entropy perovskite, and the general formula is LnXnO 3‑δ , where Ln is (Ba / Sr / Ca) 1‑x (Gd / La) x , x = 0 to 0.2, Xn is composed of 5 or more elements in an equiatomic ratio, which includes Co and Fe elements, and also includes any 3 or more elements among Zr, Sn, Pr, Nb, Mo, Mn, Ni, Cu, Zn and Ti elements, and δ is 0 to 0.4. The ABO3-type high-entropy perovskite material in the present invention can simultaneously transport electrons, oxygen ions and protons, can effectively reduce the polarization resistance of the cathode of a proton-conducting solid oxide fuel cell, improve the power density of the cell, and the cathode material can maintain good structural stability in a high water vapor atmosphere, and can effectively enhance the output stability of the cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical materials, and particularly relates to a high-entropy perovskite cathode material, a preparation method thereof, and an application thereof. Background Art

[0002] A proton-conducting solid oxide fuel cell (PC-SOFC) is a new type of energy conversion device designed based on a proton-conducting ceramic electrolyte. Structurally, it is very similar to a traditional oxygen-ion-conducting solid oxide fuel cell (O-SOFC). The biggest difference between the two lies in the function of the electrolyte. The electrolyte of O-SOFC uses an oxygen-ion-conducting ceramic oxide, while PC-SOFC uses a proton-conducting ceramic oxide. Compared with oxygen-ion transport, the activation energy required for proton transport in ceramic oxides is very small, which means that PC-SOFC has a very low temperature dependence and can operate in the temperature range of 400-600 °C, which is very consistent with the current research trend of reducing the operating temperature of solid oxide dye cells (SOFC). Therefore, PC-SOFC has received much attention in the field of energy conversion in recent years. However, since the decrease in operating temperature will cause a sharp increase in the polarization resistance of the cathode oxygen reduction reaction, it is necessary to develop a high-performance cathode catalyst to reduce the polarization resistance.

[0003] Currently, the cathode materials used in PC-SOFC mainly originate from the cathodes of O-SOFC, and mainly use La 0.8 Sr 0.2 Co 1- x Fe x O 3-δ (LSCF), Ba 0.5 Sr 0.5 Co 1-x Fe x O 3-δ (BSCF) and other perovskite oxides with mixed oxygen-ion-electron conduction functions as electrocatalysts. However, these perovskite materials have the following two problems in PC-SOFC: (1) LSCF and BSCF materials do not have the function of bulk proton transport, resulting in the cathode reaction active sites being mainly limited at the "electrolyte-cathode-air" triple-phase interface, and the intrinsic catalytic activity is not good; (2) Water is generated at the cathode of PC-SOFC, and the phase structure of LSCF and BSCF is unstable in a high partial pressure atmosphere, and additional impurity phases will be generated, resulting in a decrease in the electrode stability. Therefore, developing a cathode material with an intrinsic proton transport function and maintaining a stable structure in a high water vapor atmosphere is the key to the development of PC-SOFC.

[0004] High-entropy oxides (HEOs) are a class of functional ceramics usually composed of five or more elements in equiatomic or near-equiatomic ratios. On the one hand, these elements share the same atomic sites in a disordered arrangement, with a large mixing entropy, and thus tend to form a single-phase solid solution structure, which can inhibit the formation of other impurity phases and has extremely high structural stability. On the other hand, due to the certain differences in radius and electronegativity of different elements at the same atomic site, there will be a large lattice distortion in the structure. Therefore, high-entropy oxides often exhibit better structural stability and ion transport properties than traditional oxides. These excellent properties have greatly stimulated the research interest of researchers in high-entropy oxides, and a series of high-entropy oxides have been synthesized and proven to have good lithium-ion transport performance. At present, high-entropy oxides are still in the stage of synthetic exploration, and new properties need to be further developed. There is a lack of research on the oxygen ion and proton transport properties of high-entropy oxides, and there are no reports and open patents on using high-entropy oxides as PC-SOFC electrode materials.

[0005] In summary, it is urgently needed in the electrochemical field to enrich the research on the proton transport properties of high-entropy oxides and invent an electrode material with a small polarization resistance and good structural stability and ion transport properties. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-entropy perovskite cathode material with a small polarization resistance and good structural stability and ion transport properties.

[0007] A high-entropy perovskite cathode material, the cathode material is an ABO 3 type high-entropy perovskite material, and its general formula is LnXnO 3-δ , where Ln is (Ba / Sr / Ca) 1-x (Gd / La) x , x = 0 - 0.2, Xn is composed of five or more elements in equiatomic ratio, which includes Co and Fe elements, and also includes any three or more elements among Zr, Sn, Pr, Nb, Mo, Mn, Ni, Cu, Zn and Ti elements, and δ is 0 - 0.4.

[0008] Further, in LnXnO 3-δ , Ln is Ba element, and Xn is composed of Co, Fe, Zr, Sn and Pr elements in equiatomic ratio.

[0009] Further, in LnXnO 3-δ , Ln is Ba element, and Xn is composed of Co, Fe, Zr, Sn and Ti elements in equiatomic ratio.

[0010] The preparation method of the above-mentioned high-entropy perovskite cathode material is obtained by solid-phase synthesis method, sol-gel method, combustion method, hydrothermal method or solvothermal method.

[0011] Application of the above-mentioned high-entropy perovskite cathode material in the preparation of a symmetrical cell.

[0012] Further, using BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ As the electrolyte material, where δ is 0 to 0.4, the slurry obtained by mixing the high-entropy perovskite cathode material, binder and organic solvent is coated on both sides of the electrolyte sheet to prepare a symmetrical cell.

[0013] Application of the above-mentioned high-entropy perovskite cathode material in the preparation of a proton-conducting solid oxide fuel cell.

[0014] Using the above-mentioned high-entropy perovskite cathode material as the cathode, and using BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ As the electrolyte material, and using the powder prepared from BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ As the anode, where δ is 0 to 0.4, and NiO accounts for 30% to 70% of the total mass of BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ To prepare a proton-conducting solid oxide fuel cell.

[0015] Further, during operation, a fuel gas is introduced into the anode, and the fuel gas is hydrogen, methane, methanol or carbon monoxide.

[0016] The working principle of the proton-conducting solid oxide fuel cell prepared using the high-entropy perovskite cathode material in the present invention is as follows: First, the H + ions generated at the anode are transferred through the electrolyte to the reaction active sites in contact with O 2 at the PC-SOFC cathode, and O 2 undergoes electrochemical reduction to generate H 2 O, while releasing electrons. The metal current collector provides a transmission channel for the electrons, forming an electric current in the external circuit.

[0017] Adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0018] The high-entropy perovskite synthesized in the present invention, as the cathode material of a proton-conducting solid oxide fuel cell, can maintain a stable phase structure even in a strongly reducing atmosphere with a wet cathode, indicating that the high-entropy cathode has good structural stability and can conduct electrons, ions, and protons simultaneously. Such a triple-conducting cathode material reduces the interfacial resistance and achieves a high power output. In the present invention, BaCo 0.2 Fe 0.2 Zr 0.2 Sn 0.2 Pr 0.2 O 3-δ (BCFZSP) high-entropy perovskite cathode material can reach a maximum output power of 0.30 W / cm 2 at a working temperature of 500 °C. At 550 °C, a constant current output can be achieved at a current density of 0.42 A / cm 2 , and it can operate stably for 500 h; BaCo 0.2 Fe 0.2 Zr 0.2 Sn 0.2 Ti 0.2 O 3-δ (BCFZST) high-entropy perovskite cathode material can reach a maximum output power of 0.26 W / cm 2 at a working temperature of 500 °C. At 550 °C, a constant current output can be achieved at a current density of 0.36 A / cm 2 , and it can operate stably for 500 h. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is the XRD pattern of the BCFZSP high-entropy perovskite material prepared by the solid-phase synthesis method.

[0020] Figure 2 FIG. is the XRD pattern of the BCFZSP high-entropy perovskite material synthesized by the sol-gel method.

[0021] Figure 3 FIG. is the XRD pattern of the BCFZST high-entropy perovskite material prepared by the solid-phase synthesis method.

[0022] Figure 4 FIG. is the XRD pattern of the BCFZST high-entropy perovskite material synthesized by the sol-gel method.

[0023] Figure 5 FIG. is the total conductivity diagram measured by the DC four-probe method for the BCFZSP high-entropy perovskite material prepared by the solid-phase synthesis method and the BCFZST high-entropy perovskite material prepared by the solid-phase synthesis method.

[0024] Figure 6 FIG. is the conductance relaxation diagram of the BCFZSP high-entropy perovskite material prepared by the solid-phase synthesis method under the change of water partial pressure.

[0025] Figure 7 Conductance relaxation diagram of BCFZST high-entropy perovskite material prepared by solid-phase synthesis method under changing water partial pressure.

[0026] Figure 8 Polarization impedance diagram of electrolyte-supported symmetrical cell assembled with BCFZSP high-entropy perovskite material prepared by solid-phase synthesis method under different water partial pressures.

[0027] Figure 9 Polarization impedance diagram of electrolyte-supported symmetrical cell assembled with BCFZST high-entropy perovskite material prepared by solid-phase synthesis method under different water partial pressures.

[0028] Figure 10 Discharge curve of proton-conducting solid oxide fuel cell assembled with BCFZSP high-entropy perovskite material prepared by solid-phase synthesis method as the cathode.

[0029] Figure 11 Stability test curve of proton-conducting solid oxide fuel cell assembled with BCFZSP high-entropy perovskite material prepared by solid-phase synthesis method as the cathode.

[0030] Figure 12 Discharge curve of proton-conducting solid oxide fuel cell assembled with BCFZST high-entropy perovskite material prepared by solid-phase synthesis method as the cathode.

[0031] Figure 13 Stability test curve of proton-conducting solid oxide fuel cell assembled with BCFZST high-entropy perovskite material prepared by solid-phase synthesis method as the cathode. Detailed implementation manners

[0032] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0033] Embodiment 1

[0034] Prepare BaCo by solid-phase synthesis method 0.2 Fe 0.2 Zr 0.2 Sn 0.2 Pr 0.2 O 3-δHigh-entropy perovskite materials, and the specific preparation process is as follows: Weigh 3.9468 g of barium carbonate, 0.321 g of cobalt(III) oxide, 0.3194 g of iron(III) oxide, 0.4929 g of zirconia, 0.6810 g of praseodymium(III) oxide undecoxide, and 0.6028 g of tin(IV) oxide. After mixing, add 10 mL of absolute ethanol and ball-mill in a planetary ball mill for 24 h at a ball mill speed of 400 r / min to obtain a precursor. Grind the precursor and calcine it at 1200 °C for 2 h in an air atmosphere to obtain BCFZSP powder. Perform XRD analysis on the obtained powder, and the results are as Figure 1 shown.

[0035] Example 2

[0036] Synthesize BaCo 0.2 Fe 0.2 Zr 0.2 Sn 0.2 Pr 0.2 O 3-δ High-entropy perovskite materials, and the specific preparation process is as follows: Weigh 2.6134 g of barium nitrate, 2.9103 g of cobalt(II) nitrate hexahydrate, 4.04 g of iron(III) nitrate nonahydrate, 2.3123 g of zirconyl nitrate, 4.3501 g of praseodymium(III) nitrate hexahydrate, 2.6052 g of tin(IV) chloride, 4.2028 g of citric acid monohydrate, and 8.7672 g of ethylenediaminetetraacetic acid. After mixing, gradually dropwise add ammonia water until the solution becomes clear. Heat the solution in an 80 °C water bath until a stable gel is formed. Keep the gel at 250 °C for 2 h and sinter it at 1200 °C for 2 h to finally obtain BCFZSP powder. Perform XRD analysis on the obtained powder, and the results are as Figure 2 shown.

[0037] Example 3

[0038] Synthesize BaCo 0.2 Fe 0.2 Zr 0.2 Sn 0.2 Ti 0.2 O 3-δ High-entropy perovskite materials, and the specific preparation process is as follows: Weigh 3.9468 g of barium carbonate, 0.321 g of cobalt(II) oxide, 0.3194 g of iron(III) oxide, 0.4929 g of zirconia, 0.3195 g of titanium(IV) oxide, and 0.6028 g of tin(IV) oxide. After mixing, add 10 mL of absolute ethanol and ball-mill in a planetary ball mill for 24 h at a ball mill speed of 400 r / min to obtain a precursor. Grind the precursor and calcine it at 1200 °C for 2 h in an air atmosphere to obtain BCFZST powder. Perform XRD analysis on the obtained powder, and the results are as Figure 3 shown.

[0039] Example 4

[0040] Synthesize BaCo 0.2 Fe 0.2 Zr 0.2 Sn 0.2 Ti 0.2 O 3-δ high-entropy perovskite materials by the sol-gel method. The specific preparation process is as follows: Weigh 2.6134 g of barium nitrate, 2.9103 g of cobalt nitrate hexahydrate, 4.04 g of iron nitrate nonahydrate, 2.3123 g of zirconium oxynitrate, 1.8968 g of titanium tetrachloride, 2.6052 g of tin tetrachloride, 4.2028 g of citric acid monohydrate and 8.7672 g of ethylenediaminetetraacetic acid and mix them. After mixing, slowly drip ammonia water into the mixture until the solution becomes clear. Heat the solution in a water bath at 80 °C until a stable gel is formed. Keep the gel at 250 °C for 2 h and sinter it at 1200 °C for 2 h to finally obtain the BCFZST powder. Perform XRD analysis on the obtained powder, and the results are as Figure 4 shown.

[0041] It can be Figures 1-4 seen that single-phase perovskite oxides can be successfully prepared by the solid-phase synthesis method and the sol-gel method.

[0042] Example 5

[0043] Prepare an electrolyte-supported symmetric cell with the BCFZSP high-entropy perovskite material. The specific preparation process is as follows: Use the BCFZSP high-entropy perovskite material prepared by the solid-phase synthesis method as the cathode, and use BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ (BZCYY) as the electrolyte material. Weigh 0.1 g of the cathode material powder, 0.008 g of ethyl cellulose and 0.012 g of corn starch in a tall weighing bottle, add 1.5 mL of terpineol, and stir on a magnetic stirring table for 12 h to obtain a screen-printing paste. Use a 200-mesh screen to brush the prepared paste on both the front and back sides of the electrolyte sheet, brushing twice on each side. The second brush can only be done after the first brush is completely dry. After all are completely dry, put them into a muffle furnace at 1100 °C and calcine for 2 h. Place the coiled silver wire on top of the two electrodes after calcination, and use silver paste to tightly adhere it to them. After the silver paste is dry, put it into a muffle furnace at 750 °C and burn for 30 min to prepare the electrolyte-supported symmetric cell.

[0044] Example 6

[0045] Prepare an electrolyte-supported symmetric cell using the BCFZST high-entropy perovskite material. The specific preparation process is as follows: Use the BCFZST high-entropy perovskite material prepared by the solid-phase synthesis method as the cathode, and BZCYY as the electrolyte material. Weigh 0.1 g of the cathode material powder, 0.008 g of ethyl cellulose, and 0.012 g of corn starch into a tall weighing bottle, add 1.5 mL of terpineol, and stir on a magnetic stirrer for 12 h to obtain a screen-printing slurry. Apply the prepared slurry to both the front and back sides of the electrolyte sheet using a 200-mesh screen, brushing twice on each side. The second brush can only be done after the first brush is completely dry. After all are completely dry, place them in a muffle furnace at 1100 °C and calcine for 2 h. Place the coiled silver wire on top of the two electrodes after calcination, and use silver paste to tightly adhere it to them. After the silver paste is dry, place it in a muffle furnace at 750 °C and burn for 30 min to obtain the electrolyte-supported symmetric cell.

[0046] Example 7

[0047] Prepare a proton-conducting solid oxide fuel cell using the BCFZSP high-entropy perovskite material. The specific preparation process is as follows: Add 20 g of BZCYY, 30 g of NiO, 15 g of corn starch, and 30 mL of a 5% PVA aqueous solution by mass to a ball-milling tank and ball-mill for 6 h. Then dry it and continue ball-milling for 6 h to obtain the anode dry powder. Use BZCYY as the electrolyte material and dry-press the electrolyte on the anode support by co-pressing. Use the BCFZSP high-entropy perovskite material prepared in Example 1 as the cathode material. Place 0.1 g of the cathode material, 0.008 g of ethyl cellulose, and 0.012 g of corn starch in a measuring flask, and add 1.5 mL of terpineol to the measuring flask. Stir on a magnetic stirrer for 12 h to obtain a screen-printing slurry, and print the cathode material on the electrolyte by screen printing to make a proton-conducting solid oxide fuel cell.

[0048] Example 8

[0049] Prepare a proton-conducting solid oxide fuel cell using the BCFZST high-entropy perovskite material. The specific preparation process is as follows: Add 20 g of BZCYY, 30 g of NiO, 15 g of corn starch, and 30 mL of a 5% PVA aqueous solution by mass to a ball-milling tank and ball-mill for 6 h. Then dry it and continue ball-milling for 6 h to obtain the anode dry powder. Use BZCYY as the electrolyte material and dry-press the electrolyte on the anode support by co-pressing. Use the BCFZST high-entropy perovskite material prepared in Example 3 as the cathode material. Place 0.1 g of the cathode material, 0.008 g of ethyl cellulose, and 0.012 g of corn starch in a measuring flask, and add 1.5 mL of terpineol to the measuring flask. Stir on a magnetic stirrer for 12 h to obtain a screen-printing slurry, and print the cathode material on the electrolyte by screen printing to make a proton-conducting solid oxide fuel cell.

[0050] Experimental Example 1

[0051] Rectangular parallelepiped splines prepared by the dry pressing method were used to test the total conductivity of the cathode materials obtained in Example 1 and Example 3 respectively. The specific process is as follows: The cathode powder to be tested was ground into fine powder with an appropriate amount of 5% PVA aqueous solution in a mortar. Subsequently, a tablet press was used to press the mold filled with the fine powder to obtain a rectangular parallelepiped green body. The green body was calcined at 1200 °C for 2 h to obtain a dense spline. Four silver wires were connected in parallel on the rectangular parallelepiped spline as electrode leads during the conductivity test. The conductivities of BCFZSP and BCFZST were measured as Figure 5 shown below.

[0052] As Figure 5 shown, with the increase of temperature, the conductivities of BCFZSP and BCFZST gradually increase. The conductivity of BCFZSP is 0.94 S / cm at 550 °C and rises to 1.91 S / cm at 750 °C; the conductivity of BCFZST is 0.69 S / cm at 550 °C and rises to 1.66 S / cm at 750 °C.

[0053] Experimental Example 2

[0054] Measure the change of the conductivity of the BCFZSP high-entropy perovskite material with time under the change of water partial pressure. The specific process is as follows: The BCFZSP high-entropy perovskite material obtained in Example 1 was dry-pressed to obtain a rod with a density of more than 95%. It was sintered at 1200 °C for 2 h. A silver wire was connected to the conductive bar through a Keithley 2400 source meter for four-probe conductivity measurement. During the measurement process, an argon-oxygen mixed gas atmosphere (21% O 2 + 79% Ar) rapidly changed from the dry state to the wet state (pH 2 O = 0.1 atm). At 600 °C, the change of the conductivity of the BCFZSP high-entropy perovskite material with time under the change of water partial pressure was measured, and the measurement results are as Figure 6 shown below.

[0055] As Figure 6 can be seen, the conductivity first undergoes a rapid decrease process, and then gradually increases and levels off. It can be considered that in the step of hole redistribution during the hydration reaction process of this material, the consumption rate of holes is faster than the generation rate of holes. The generation of protons on the surface of this material and the diffusion rate to the bulk phase are faster than the incorporation process of oxygen and the diffusion rate to the bulk phase, indicating its good proton conductivity. In addition, the oxygen ion diffusion coefficient DO of BCFZSP was obtained by fitting as 1.24×10 -6 cm 2 / s, and the proton diffusion coefficient DH is 6.30×10 -6 cm2 / s.

[0056] Experimental Example 3

[0057] Measure the change of the conductivity of the BCFZST high-entropy perovskite material with time under the change of water partial pressure. The specific process is as follows: The BCFZST high-entropy perovskite material prepared in Example 3 is dry-pressed to obtain a rod with a density of more than 95%, and then sintered at 1200 °C for 2 h. The silver wire is connected to the conductive bar through a Keithley 2400 source meter for four-probe conductivity measurement. During the measurement, an argon-oxygen mixed gas atmosphere (21% O 2 + 79% Ar) quickly changes from the dry state to the wet state (pH 2 O = 0.1 atm). At 600 °C, measure the change of the conductivity of the BCFZST high-entropy perovskite material with time under the change of water partial pressure. The measurement results are as Figure 7 shown.

[0058] As can be Figure 7 seen, the conductivity first undergoes a rapid decrease process, and then gradually increases and levels off. It can be considered that in the step of hole redistribution during the hydration reaction process of this material, the consumption rate of holes is faster than the generation rate of holes. The generation of protons on the surface of this material and the diffusion rate into the bulk phase are faster than the process of oxygen incorporation and diffusion into the bulk phase, indicating its good proton conductivity. In addition, through fitting, the oxygen ion diffusion coefficient D of BCFZST = 1.04×10 -6 cm 2 / s, and the proton diffusion coefficient D = 4.87×10 -6 cm 2 / s.

[0059] Experimental Example 4

[0060] Use the Autolab electrochemical workstation PGSTAT302 from Metrohm to test the electrochemical impedance spectrum of the electrolyte-supported symmetric cell prepared in Example 5 at different water partial pressures. The frequency range is set to 1 MHz to 0.1 Hz, the voltage amplitude is 10 mV, and the test temperature is 550 °C. The introduction of water vapor is achieved by using an Ar / O 2 mixed carrier gas (~80% Ar) passing through a gas collecting bottle filled with deionized water. The water partial pressure in the gas is controlled by the saturated vapor pressure of water at a fixed temperature. The test results are as Figure 8 shown.

[0061] As can be Figure 8 seen, with the increase of the water partial pressure, the corresponding polarization resistance continuously decreases. Since the increase of the water partial pressure is beneficial to promoting H 2The diffusion and adsorption of O(g) reduce the gas adsorption impedance; the proton defects generated by the hydration reaction after the adsorption of water molecules promote the ion diffusion process in the cathode bulk phase.

[0062] Experimental Example 5

[0063] The electrolyte-supported symmetric cell prepared in Example 6 was tested for electrochemical impedance spectroscopy using an Autolab electrochemical workstation PGSTAT302 from Metrohm at different water vapor pressures. The frequency range was set to 1 MHz to 0.1 Hz, the voltage amplitude was 10 mV, and the test temperature was 550 °C. The introduction of water vapor was achieved by passing an Ar / O 2 mixed carrier gas (~80% Ar) through a gas collecting bottle filled with deionized water. The water vapor pressure in the gas was controlled by the saturated vapor pressure of water at a fixed temperature. The test results are as Figure 9 shown.

[0064] It can be seen from Figure 9 that as the water vapor pressure increases, the corresponding polarization resistance continuously decreases.

[0065] Experimental Example 6

[0066] Hydrogen gas at 50 mL / min was introduced as the fuel gas into the anode side of the proton-conducting solid oxide fuel cell prepared in Example 7, and static air was used as the oxidant. The maximum power densities at 500 °C, 550 °C, 600 °C, 650 °C, and 700 °C were recorded respectively. The results are as Figure 10 shown.

[0067] It can be seen from Figure 10 that for the PC-SOFC with the BCFZSP high-entropy perovskite material as the cathode, the maximum power densities at 500 °C, 550 °C, 600 °C, 650 °C, and 700 °C can reach 0.30, 0.43, 0.68, 0.80, and 0.94 W·cm -2 .

[0068] The proton-conducting solid oxide fuel cell prepared in Example 7 was operated at a constant current density of 0.42 A / cm 2 at the working temperature of 550 °C, and the change in the output voltage of the BCFZSP-based PC-SOFC at different times was recorded. The results are as Figure 11 shown.

[0069] It can be seen from Figure 11 that from the curve of the output voltage of the BCFZSP-based PC-SOFC versus time, it can be seen that during the 500 h test time, the voltage of the battery did not show an obvious attenuation process, showing a very stable working state. Therefore, it can be considered that the BCFZSP cathode material has good stability.

[0070] Experimental Example 7

[0071] Hydrogen at 50 ml / min was introduced as the fuel gas into the anode side of the proton-conducting solid oxide fuel cell prepared in Example 8, and static air was used as the oxidant. The maximum power densities at 500 °C, 550 °C, 600 °C, 650 °C and 700 °C were recorded respectively, and the results are as Figure 12 shown.

[0072] It can be seen from Figure 12 the results that the maximum power densities of the PC-SOFC with the BCFZST high-entropy perovskite material as the cathode at 500 °C, 550 °C, 600 °C, 650 °C and 700 °C can reach 0.26, 0.43, 0.59, 0.75 and 0.86 W·cm -2 .

[0073] The proton-conducting solid oxide fuel cell prepared in Example 8 was operated at a constant current density of 0.36 A / cm 2 at the working temperature of 550 °C, and the change of the output voltage of the BCFZST-based PC-SOFC at different times was recorded. The results are as Figure 13 shown.

[0074] It can be seen from Figure 13 the change curve of the output voltage of the BCFZST-based PC-SOFC with time that during the 500 h test time, the voltage of the fuel cell did not show an obvious attenuation process, indicating a very stable working state. Therefore, it can be considered that the BCFZST cathode material has good stability.

Claims

1. A high-entropy perovskite cathode material, characterized in that, The cathode material is BaCo 0.2 Fe 0.2 Zr 0.2 Sn 0.2 Pr 0.2 O 3-δ or BaCo 0.2 Fe 0.2 Zr 0.2 Sn 0.2 Ti 0.2 O 3-δ , where δ ranges from 0 to 0.

4.

2. A method for preparing the high-entropy perovskite cathode material according to claim 1, characterized in that, it is prepared by a solid-phase synthesis method, a sol-gel method, a combustion method, a hydrothermal method or a solvothermal method.

3. Application of the high-entropy perovskite cathode material according to claim 1 in preparing a symmetrical cell.

4. According to the application described in claim 3, characterized in that, Using BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ material as the electrolyte, where δ is 0 to 0.4, and the slurry obtained by mixing and stirring the high-entropy perovskite cathode material, binder and organic solvent is coated on both sides of the electrolyte sheet to prepare a symmetric cell.

5. Application of the high-entropy perovskite cathode material according to claim 1 in preparing a proton-conducting solid oxide fuel cell.

6. According to the application described in claim 5, characterized in that, Using the high-entropy perovskite cathode material as the cathode, BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ material as the electrolyte, and a powder prepared from BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ material, NiO and a binder as the anode, where δ is 0 to 0.4, and NiO accounts for 30% to 70% of the total mass of BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ material and NiO, to prepare a proton-conducting solid oxide fuel cell.

7. According to the application described in claim 6, characterized in that, when the proton-conducting solid oxide fuel cell operates, a fuel gas is introduced into the anode, and the fuel gas is hydrogen, methane, methanol or carbon monoxide.

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