High-entropy oxygen electrode for solid oxide battery and preparation method of high-entropy oxygen electrode

Abstract

The invention belongs to the technical field of solid oxide batteries, and relates to a high-entropy oxygen electrode for a solid oxide battery, the chemical formula is PraBabSrcLadNdeM1xM21-xO3-delta, a + b + c + d + e = 1, 0.15 < = a < = 0.25, 0.1 < = b < = 0.3, 0.1 < = c < = 0.3, 0.15 < = d < = 0.25, 0.15 < = e < = 0.25, 0.2 < = b + c < = 0.4, 0.5 < = x < = 1.0, five metal elements of Pr, Ba, Sr, La and Nd simultaneously exist at a point A, M1 is any one of Co, Ni and Mn, M2 is any one of Mo, Ti, Cr, Cu and Zn, and delta represents a non-stoichiometric oxygen vacancy. According to the invention, La and Nd are used for partially replacing alkaline earth metal elements at the A site, so that the material keeps relatively high electrochemical performance while the content of alkaline earth metal is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid oxide batteries, and in particular relates to a high-entropy oxygen electrode for a solid oxide battery and a preparation method thereof. Background Art

[0002] Proton-Conducting Reversible Solid Oxide Cells (P-RSOCs) are highly efficient energy conversion and storage devices that can flexibly switch between fuel cell and electrolyzer modes. They have the characteristics of medium temperature operation (400-700℃), strong fuel adaptability and environmental friendliness. Among them, the oxygen electrode, also known as the air electrode, needs to have a triple conductivity of protons, oxygen ions and electrons (such as Ruddlesden-Popper type Nd 0.8 Sr 1.2 Ni 0.7 Fe 0.3 O4±δ) to accelerate the oxygen reduction / evolution reaction.

[0003] High entropy oxides (HEO) exhibit remarkable physical and chemical properties due to their unique chemical composition and disordered organization of multiple elements (≥5 metal elements; each metal element is doped at the same site of the perovskite at a molar ratio of 5-35%; when the various elements are added in equimolar proportions, the configurational entropy of the material is the largest). They not only have excellent ionic conductivity, but also have excellent stability and dielectric constant. Therefore, HEO materials have potential application prospects as oxygen electrodes in R-PSOCs and related electrocatalytic fields. Hou et al. (J.Gong, J.Hou, B-site high-entropy tailoring K2NiF4oxide as an effective cathode for proton-conducting solid oxide fuel cells, J.Mater.Sci.Technol.186(2024)158-163) used La 1.2 Sr 0.8 NiO 4+δ (LSN) as a prototype, a B-site high entropy oxygen electrode material La with low polarization resistance was designed and prepared. 1.2 Sr 0.8 Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cu 0.2 O 4+δYe et al. (X.Zhang, C.Tang, Y.Yang, F.Zheng, Q.Su, H.Xiang, L.Meng, L.Du, Y.Aoki, D.Luo, N.Wang, S.Ye, Novel high-entropy air electrodes enhancing electrochemical performances of reversible protonic ceramic cells, Adv.Funct.Mater.(2025)2421083-2421094) designed and prepared a B-site high entropy oxygen electrode material LaCo 0.2 Cu 0.2 Fe 0.2 Ni 0.2 Me 0.2 O 3-δ (Me=Al, Mn, Cr). However, studies have found that the high entropy of the B site will significantly reduce the content of the Co element, thereby reducing the oxygen evolution reaction (OER) activity of the material. Therefore, people have turned their attention to high entropy oxygen electrode materials at the A site. Recently, a series of A-site high entropy oxygen electrode materials with high OER activity have been designed and developed, such as: Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Ca 0.2 CoO 3-δ (PBSLCC), Pr 1 / 6 La 1 / 6 Nd 1 / 6 Ba 1 / 6 Sr 1 / 6 Ca 1 / 6 CoO 3-δ (PLNBSCC) ] and xNiO-Pr 0.2 La 0.2 Ba 0.2 Sr 0.2 Ca 0.2 Fe 0.8 Ni 0.2-x O 3-δ (N-XFN). However, in most current A-site high-entropy oxygen electrode materials, the molar content of alkaline earth metal elements is high (≥50%) to maintain high water-binding capacity. Studies have found that high alkaline earth metal content can significantly degrade the electrochemical performance of oxygen electrode materials. Summary of the Invention

[0004] In order to solve the above problems, the present invention partially replaces the alkaline earth metal elements at the A site with lanthanide elements La and Nd, thereby reducing the alkaline earth metal content while maintaining high electrochemical performance of the material. At the same time, by systematically studying the doping of transition metal elements at the B site, a high-entropy oxygen electrode material for a proton-conducting reversible solid oxide battery with a low alkaline earth metal content, a thermal expansion coefficient compatible with the electrolyte material, and high electrochemical performance is prepared. The present invention solves the problem of significant performance degradation of the high-entropy oxygen electrode material at the A site by preparing a class of high-entropy oxygen electrode materials suitable for proton conductor solid oxide batteries. More importantly, the prepared high-entropy oxygen electrode material at the A site can maintain high electrochemical performance and long-term stability while further reducing the alkaline earth metal content at the A site, and achieves a higher current density under the conditions of electrolysis of H2O and co-electrolysis of CO2-H2O, further expanding the application scenarios of the material.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A high entropy oxygen electrode for solid oxide batteries, with the chemical formula Pr a Ba b Sr c La d Nd e M1 x M2 1-x O 3-δ , where a+b+c+d+e=1, 0.15≤a≤0.25, 0.1≤b≤0.3, 0.1≤c≤0.3, 0.15≤d≤0.25, 0.15≤e≤0.25, 0.2≤b+c≤0.4, 0.5≤x≤1.0, five metal elements Pr, Ba, Sr, La, and Nd exist at point A at the same time, M1 is any one of Co, Ni, and Mn, M2 is any one of Mo, Ti, Cr, Cu, and Zn, and δ represents a non-stoichiometric oxygen vacancy.

[0007] Furthermore, M1 is Co and M2 is Cr.

[0008] Furthermore, 0.8≤x≤0.9.

[0009] Furthermore, the high entropy oxygen electrode for solid oxide battery has a chemical formula of Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co0.9 Cr 0.1 、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Cr 0.2 .

[0010] The inventors unexpectedly discovered that in the general formula Pr a Ba b Sr c La d Nd e M1 x M2 1-x O 3-δ Within the range, the above is Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.9 Cr 0.1 、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Cr 0.2 showed the best electrochemical performance, especially Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.9 Cr 0.1 、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Cr 0.2 When M2 is other metals, the effect is not good. The possible reason is that Cr has a high electronegativity and strong electron attraction ability, which can induce electron transfer from Co to Cr, adjust the d-band center position of Co, and make it closer to the top of the "volcano curve" in the Sabatier principle, thereby optimizing the oxygen intermediates (such as O - 、O2 -) and significantly improve the kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In addition, Cr and Co have a synergistic effect, which can inhibit transition metal migration and lattice oxygen release, and reduce structural degradation. Cr doping and Co can increase the oxygen vacancy formation energy and inhibit phase transition during the cycle. This synergistic effect was not found when M2 is other metals. On the contrary, when M2 is other metals, its performance is not as good as when M1 is Co alone, that is, Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co.

[0011] The present invention also provides a method for preparing the high entropy oxygen electrode for the solid oxide battery, which includes a solid phase method, a sol-gel method, a citric acid-nitrate combustion method or a glycine-nitrate combustion method.

[0012] Furthermore, the preparation method of the high entropy oxygen electrode for solid oxide battery is a sol-gel method, comprising the following steps:

[0013] (S1) According to Pr a Ba b Sr c La d Nd e M1 x M2 1-x O 3-δ A chelating agent and a metal salt containing Pr, Ba, Sr, La, Nd, M1, and M2 are dissolved in water in a stoichiometric ratio to form a mixed solution, and then a pH regulator is used to adjust the pH of the mixed solution to 7.5 to 8.5, and then the mixed solution is heated and evaporated under stirring to obtain a gel;

[0014] (S2) calcining and crushing the gel in air atmosphere to obtain the product Pr a Ba b Sr c La d Nd e M1 x M2 1-x O 3-δ .

[0015] Furthermore, in step (S1), the chelating agent is at least one of oxalic acid, citric acid, and ethylenediaminetetraacetic acid; the metal salt is at least one of metal nitrate, oxalate, acetate, and halide; and the pH adjuster is ammonia water, sodium bicarbonate, or triethanolamine.

[0016] Furthermore, in step (S1), the molar ratio of the chelating agent to the total metal ions is (2-5):1, and the total metal ions are the sum of Pr, Ba, Sr, La, Nd, M1, and M2.

[0017] Furthermore, in step (S2), the calcination temperature is 900-1200°C, preferably 950-1050°C.

[0018] The present invention also provides a proton-conducting reversible solid oxide battery, comprising a hydrogen electrode, an oxygen electrode, and an electrolyte, wherein the oxygen electrode is the high-entropy oxygen electrode for the solid oxide battery.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention utilizes La and Nd to partially replace the alkaline earth metal elements at the A site, thereby reducing the alkaline earth metal content while maintaining high electrochemical performance of the material.

[0021] 2. Using high entropy oxygen electrode (Pr a Ba b Sr c La d Nd e M1 x M2 1-x O 3-δ ), Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.9 Cr 0.1 、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Cr 0.2 Demonstrated excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A homemade battery testing device.

[0023] Figure 2 Pr synthesized in Example 1 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 CoO3-δ XRD pattern of (PBSLNC) powder.

[0024] Figure 3 TEC curve of the PBSLNC material of Example 1 in the range of 350°C to 850°C.

[0025] Figure 4 This is the current-voltage-power curve of PBSLNC||BCZYYb||BCZYYb-Ni battery.

[0026] Figure 5 This is the surface micromorphology of the PBSLNC oxygen electrode after the electrochemical performance and stability test of the PBSLNC||BCZYYb||BCZYYb-Ni battery.

[0027] Figure 6 This is the current-voltage curve of the PBSLNC||BCZYYb||BCZYYb-Ni battery for electrolysis of H2O.

[0028] Figure 7 This is the current-voltage curve of the PBSLNC||BCZYYb||BCZYYb-Ni battery for co-electrolysis of CO2-H2O.

[0029] Figure 8 These are the long-term stability test results of PBSLNC||BCZYYb||BCZYYb-Ni fuel cells. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to specific examples, but the present invention is not limited to the following examples.

[0031] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0032] Figure 1 Schematic diagram of the homemade battery testing device.

[0033] Example 1

[0034] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 CoO 3-δCitric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, and cobalt nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the solution is adjusted to about 8 with aqueous ammonia (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0035] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 CoO 3-δ (PBSLNC) powder.

[0036] Figure 2 Pr synthesized in Example 1 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 CoO 3-δ (PBSLNC) powder XRD pattern. It can be seen that the diffraction peaks of PBSLNC are all consistent with Pr 0.5 Ba 0.5 The main diffraction peaks correspond to those represented by the PDF standard card of CoO3 (PDF No#: 01-072-7225), proving that the five elements Pr, Ba, Sr, La, and Nd are simultaneously doped into the A site of the perovskite material, and the doped PBSLNC still maintains the perovskite structure without being destroyed.

[0037] Figure 3 The TEC curve of the PBSLNC material of Example 1 in the range of 350°C to 850°C is shown in FIG. Figure 3 The calculated TEC of PBSLNC is 12.02×10 -6 K -1 , and the TEC of the electrolyte BCZYYb material (about 12.0×10 -6 K -1 ) almost coincide with each other. TEC calculation results show that PBSLNC and BCZYYb have excellent thermal compatibility within the battery operating temperature range.

[0038] Example 2

[0039] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2NiO 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, and nickel nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with aqueous ammonia (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0040] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 NiO 3-δ powder.

[0041] Example 3

[0042] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 MnO 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, and manganese nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with aqueous ammonia (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0043] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 MnO 3-δ powder.

[0044] Example 4

[0045] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Cr 0.2 O 3-δCitric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, cobalt nitrate, and chromium nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with ammonia water (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0046] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Cr 0.2 O 3-δ powder.

[0047] Example 5

[0048] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.9 Cr 0.1 O 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, cobalt nitrate, and chromium nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with ammonia water (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0049] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.9 Cr 0.1 O 3-δ powder.

[0050] Example 6

[0051] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co0.6 Cr 0.4 O 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, cobalt nitrate, and chromium nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with ammonia water (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0052] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.6 Cr 0.4 O 3-δ powder.

[0053] Example 7

[0054] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Zn 0.2 O 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, cobalt nitrate, and zinc nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with ammonia water (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0055] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Zn 0.2 O 3-δ powder.

[0056] Example 8

[0057] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2La 0.2 Nd 0.2 Co 0.8 Mo 0.2 O 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, cobalt nitrate, and molybdenum nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with ammonia water (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0058] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Mo 0.2 O 3-δ powder.

[0059] Example 9

[0060] (1)Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Ti 0.2 O 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, cobalt nitrate, and titanium nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with ammonia water (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0061] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Ti 0.2 O 3-δ powder.

[0062] Example 10

[0063] (1) According to the chemical formula Pr 0.2Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Mn 0.8 Cr 0.2 O 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, manganese nitrate, and chromium nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with ammonia water (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0064] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Mn 0.8 Cr 0.2 O 3-δ powder.

[0065] Example 11

[0066] (1) According to the chemical formula Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Ni 0.8 Cr 0.2 O 3-δ Citric acid, ethylenediaminetetraacetic acid, praseodymium nitrate, barium nitrate, strontium nitrate, lanthanum nitrate, hydrated neodymium acetate, nickel nitrate, and chromium nitrate are dissolved in deionized water in a stoichiometric ratio, wherein the total molar weight of citric acid:ethylenediaminetetraacetic acid:metal ions is 2:1:1, and then the pH of the above solution is adjusted to about 8 with ammonia water (NH3·H2O), and then the solvent is evaporated under stirring and heating to obtain a gel;

[0067] (2) The gel obtained in step (1) was calcined in air at 950°C for 4 hours in a muffle furnace, and the calcined product was air-pulverized to 300-400 mesh to obtain Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Ni 0.8 Cr 0.2 O 3-δ powder.

[0068] Application Examples

[0069] The high entropy oxygen electrode material of the above embodiment is used in P-SOC, and the assembly process is as follows:

[0070] (1) 57wt.% NiO, 30wt.% BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ Powders consisting of (BCZYYb) and 13 wt.% starch were mixed and ball-milled in ethanol for 24 h, then dried and uniaxially pressed into sheets with a diameter of 15 mm, and then fired at 1100 °C for 2 h to form green porous hydrogen electrode substrates.

[0071] (2) 1 wt.% NiO, a sintering aid, was mixed with BCZYYb powder and thoroughly dispersed in an organic dispersant to form a stable suspension. The suspension was then dropped onto the center of the anode substrate and immediately spun at 2500 rpm for 30 seconds to form a thin, uniform BCZYYb layer. The coating was then dried at room temperature to remove the solvent. This completes one electrolyte layer cycle. The electrolyte thickness was controlled by the spin coater's rotation speed and the number of cycles.

[0072] (3) The resulting hydrogen electrode-electrolyte double-layer structure was then co-sintered in a muffle furnace at 1450 °C for 5 h to obtain a dense BCZYYb electrolyte, thereby preparing a half-cell.

[0073] (4) Using a screen printing method, the oxygen electrodes of Examples 1-14 were each mixed with an organic solvent (terpineol:ethyl cellulose = 96:4) at a mass ratio of 1:1.5 in a mortar and ground for 1 hour to obtain an oxygen electrode material slurry. This oxygen electrode material slurry was then coated onto the surface of the sintered electrolyte. After drying, the sample was calcined at 950°C for 2 hours to complete the fabrication of the single cell.

[0074] The single cell was tested using a homemade test device. Specifically, the single cell was sealed on an alumina tube using conductive silver paste, and Ag wires fixed with conductive silver paste were connected to the device to serve as the hydrogen electrode and oxygen electrode wiring of the cell. In order to evaluate the cell performance using H2 fuel, electrolysis of H2O, and CO2-H2O co-electrolysis, about 3% volume of water vapor was generated at room temperature through a water bubbler before the fuel was introduced into the cell. The gas flow rate was set to 30 ml min -1 The battery's power output performance and electrolysis were tested using a Thales battery test system. AC impedance spectroscopy was performed using a Zennium electrochemical workstation in the frequency range of 0.01 Hz to 1 MHz under 10 mV AC perturbation.

[0075] The PBSLNC prepared in Example 1 was used as the oxygen electrode material and assembled into a battery according to the above method. Figure 4 Figure 2 shows the current-voltage-power curves for the PBSLNC||BCZYYb||BCZYYb-Ni battery. Using H₂ as fuel, the battery achieved peak power densities of 2.39 W / cm², 1.55 W / cm², 0.87 W / cm², and 0.42 W / cm² at 750°C, 700°C, 650°C, and 600°C, respectively. The fuel cell performance demonstrates the excellent oxygen reduction reaction activity of the PBSLNC high-entropy oxygen electrode.

[0076] Figure 5 The micromorphology of the PBSLNC oxygen electrode surface after the electrochemical performance and stability test of the PBSLNC||BCZYYb||BCZYYb-Ni battery. Figure 5 It can be seen that after the electrochemical performance and stability tests, the surface of the PBSLNC oxygen electrode still presents a loose and porous morphology, and the material does not agglomerate.

[0077] Figure 6 is the current-voltage curve of the PBSLNC||BCZYYb||BCZYYb-Ni battery for electrolysis of H2O. Figure 6 It can be seen that the current density of the cell for electrolyzing H2O at 750℃, 700℃, 650℃, and 600℃ is 2.37A / cm2, 1.84A / cm2, 1.39A / cm2, and 0.67A / cm2, respectively. The electrolytic cell performance shows that the PBSLNC high-entropy oxygen electrode has good oxygen evolution reaction activity.

[0078] Figure 7 The current-voltage curve of the PBSLNC||BCZYYb||BCZYYb-Ni battery for the co-electrolysis of CO2-H2O. Figure 7 It can be seen that the current density of the cell for CO2-H2O co-electrolysis at 750℃, 700℃, 650℃, and 600℃ is 4.03A / cm2, 1.77A / cm2, 0.80A / cm2, and 0.30A / cm2, respectively. The performance of the CO2-H2O co-electrolysis cell shows that the PBSLNC high-entropy oxygen electrode has good CO2-H2O co-electrolysis performance.

[0079] Figure 8 The long-term stability test results of the PBSLNC||BCZYYb||BCZYYb-Ni fuel cell are shown in Figure 2. Figure 8 It can be seen that the fuel cell using PBSLNC as the oxygen electrode can operate stably for more than 120 hours at 600°C and 0.2 ampere / square centimeter, showing good stability.

[0080] The oxygen electrodes prepared in the above examples were assembled into cells according to the above method, and their electrochemical performance was tested. The results are shown in Table 1 below. The operating temperature of proton-conducting solid oxide cells generally ranges from 500 to 750°C. Maintaining high electrochemical performance at lower temperatures can effectively reduce battery operating costs. Based on the electrochemical performance of the cells, 650°C was selected as the reference operating temperature. A higher current density indicates better oxygen electrode material performance.

[0081] Table 1 Electrochemical performance test

[0082]

Claims

1. A high entropy oxygen electrode for solid oxide batteries, characterized in that The chemical formula is Pr a Ba b Sr c La d Nd e M1 x M2 1- x O 3-δ , where a+b+c+d+e=1, 0.15≤a≤0.25, 0.1≤b≤0.3, 0.1≤c≤0.3, 0.15≤d≤0.25, 0.15≤e≤0.25, 0.2≤b+c≤0.4, 0.5≤x≤1.0, five metal elements Pr, Ba, Sr, La, and Nd exist at point A at the same time, M1 is any one of Co, Ni, and Mn, M2 is any one of Mo, Ti, Cr, Cu, and Zn, and δ represents a non-stoichiometric oxygen vacancy.

2. The high entropy oxygen electrode for solid oxide batteries according to claim 1, characterized in that M1 is Co and M2 is Cr.

3. The high entropy oxygen electrode for solid oxide batteries according to claim 1, characterized in that 0.8≤x≤0.9。 4. The high entropy oxygen electrode for solid oxide batteries according to claim 1, characterized in that The high entropy oxygen electrode for solid oxide battery has the chemical formula of Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.9 Cr 0.1 、Pr 0.2 Ba 0.2 Sr 0.2 La 0.2 Nd 0.2 Co 0.8 Cr 0.2 .

5. The method for preparing a high entropy oxygen electrode for a solid oxide battery according to any one of claims 1 to 4, characterized in that: It is a solid phase method, a sol-gel method, a citric acid-nitrate combustion method or a glycine-nitrate combustion method.

6. The preparation method according to claim 5, characterized in that It is a sol-gel method, comprising the following steps: (S1) According to Pr a Ba b Sr c La d Nd e M1 x M2 1-x O 3-δ A chelating agent and a metal salt containing Pr, Ba, Sr, La, Nd, M1, and M2 are dissolved in water in a stoichiometric ratio to form a mixed solution, and then a pH regulator is used to adjust the pH of the mixed solution to 7.5 to 8.5, and then the mixed solution is heated and evaporated under stirring to obtain a gel; (S2) calcining and crushing the gel in air atmosphere to obtain the product Pr a Ba b Sr c La d Nd e M1 x M2 1-x O 3-δ .

7. The preparation method according to claim 6, characterized in that In step (S1), the chelating agent is at least one of oxalic acid, citric acid, and ethylenediaminetetraacetic acid; the metal salt is at least one of metal nitrate, oxalate, acetate, and halide; and the pH adjuster is ammonia water, sodium bicarbonate, or triethanolamine.

8. The preparation method according to claim 6, characterized in that In step (S1), the molar ratio of the chelating agent to the total metal ions is (2-5):1, and the total metal ions are the sum of Pr, Ba, Sr, La, Nd, M1, and M2.

9. The preparation method according to claim 6, characterized in that In step (S2), the calcination temperature is 900-1200°C, preferably 950-1050°C.

10. A proton-conducting reversible solid oxide battery comprising a hydrogen electrode, an oxygen electrode, and an electrolyte, wherein the oxygen electrode is the high-entropy oxygen electrode for a solid oxide battery according to any one of claims 1 to 4.

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