High-entropy bismuth oxide-based electrolyte as well as preparation method and application thereof

Abstract

The invention discloses a high-entropy bismuth oxide-based electrolyte and a preparation method and application thereof.The preparation method comprises the steps that a rare earth salpeter solution and a multi-element-doped metal oxide ceramic electrolyte precursor material are fully mixed and dispersed, and a modified precursor material is obtained after centrifugal separation and drying; carrying out secondary roasting on the modified precursor material, and controlling the roasting temperature and time to convert the modified precursor material into a metal oxide precursor material; tabletting and molding the metal oxide precursor material, roasting the molded sheet body, and controlling the roasting temperature and time to realize high-entropy densification of the molded sheet body. According to the invention, a rare earth salpeter solution is used for modifying a multi-element doped metal oxide ceramic electrolytic precursor material prepared by a traditional method, and the high-entropy electrolyte material with high ion transmission performance is obtained through ion exchange-molding roasting and other technical routes.

Description

Technical Field

[0001] This invention relates to the fields of solid oxide batteries and energy chemical materials technology, and in particular to a high-entropy bismuth oxide-based electrolyte, its preparation method, and its application. Background Technology

[0002] Integral gasification fuel cell (IGFC) technology represents a fundamental transformation in coal-fired power generation. By deeply integrating integrated gasification combined cycle (IGCC) power generation with solid oxide fuel cells (SOFC), IGFC enables a technological leap from simple thermodynamic cycles to a hybrid electrochemical and thermodynamic cycle approach in coal-based power generation, significantly improving power generation efficiency. Simultaneously, the CO2 exhaust gas produced after power generation reaches approximately 350°C and has a concentration exceeding 90%, which can be coupled with a renewable energy-driven solid oxide electrolyzer (SOEC) to achieve near-zero carbon emissions. Therefore, IGFC is a fundamental transformative technology for coal-fired power generation.

[0003] Near-zero carbon emission IGFC systems mainly include subsystems such as coal gasification, syngas purification and desulfurization, SOFC, SOEC, and waste heat recovery. Among these, SOFC is a key technology restricting the development of IGFC. Because the conductivity of oxygen ion conductors decreases significantly at low temperatures, SOFCs mostly operate at high temperatures (>850℃), resulting in high system operating costs, insufficient stability, and poor overall technical and economic efficiency. To achieve the commercialization of IGFC, it is necessary to continuously improve technological maturity and cost competitiveness. The key lies in innovating SOFC electrolyte materials to appropriately reduce the reaction temperature and extend system life, thereby supporting the efficient, stable, and low-cost operation of SOFC and contributing to the clean and efficient utilization of coal.

[0004] Domestic and international scholars have conducted extensive research and development on electrolyte precursor materials. Invention patent CN119275334A discloses a method for preparing NASICON-structured high-entropy oxide solid electrolyte materials, introducing a method using Li... 1-3 M 0-3 Ti 1-7 Introducing quaternary high-entropy doping into (PO4)3, lattice distortion is induced through atomic size differences, thereby enhancing the Li... + The migration activation energy decreased from 0.42 eV to 0.35 eV. Patent publication CN115332619A discloses a method for preparing garnet-type oxide electrolyte materials, introducing the process using Zr... 4+ Hf 4+ Ta 5+ 、Nb 4+ Quaternary doping utilizes the similar chemical properties of elements in the same group (Zr / Hf, Ta / Nb) to stabilize the cubic phase structure, while the difference in ionic radius (Zr / Hf, Ta / Nb) further stabilizes the cubic phase structure. 4+ 0.072 nm vs Ta5+ (0.064 nm) promotes lithium vacancy formation. Patent CN113725480A discloses a method for modifying the conductivity of an inorganic-organic composite electrolyte. It describes a method of blending high-entropy oxides with PEO, utilizing the hydrogen bonding between the hydroxyl groups on the surface of the high-entropy oxides and the polymer chains to reduce the crystallinity of PEO to below 30%, while simultaneously using Li... + Rapid conduction channels on the surface of oxide particles.

[0005] However, existing high-entropy electrolyte materials still suffer from insufficient ion transport performance at medium and low temperatures. Summary of the Invention

[0006] The purpose of this invention is to provide a high-entropy bismuth oxide-based electrolyte, its preparation method and application, to improve the ion transport performance of electrolyte materials at low and medium temperatures.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a high-entropy bismuth oxide-based electrolyte is provided, comprising: Step 1: The rare earth nitric acid solution is thoroughly mixed and dispersed with the multi-element doped metal oxide ceramic electrolyte precursor material, and then the modified precursor material is obtained after centrifugation and drying. Step 2: The modified precursor material obtained in Step 1 is calcined a second time, and the calcination temperature and time are controlled to convert it into a metal oxide precursor material. Step 3: Press the metal oxide precursor material obtained in Step 2 into a sheet, and then calcine the sheet, controlling the calcine temperature and time to achieve high entropy densification.

[0008] In a preferred embodiment, in step one, the rare earth nitric acid solution is selected from one of zirconium nitrate, neodymium nitrate, and yttrium nitrate solutions.

[0009] In a preferred embodiment, in step one, the multi-element doped metal oxide ceramic electrolyte precursor material is prepared by uniformly dispersing, alkali-co-precipitating, and calcining heat treatment of a nitric acid solution containing lanthanum (La), praseodymium (Pr), samarium (Sm), gadolinium (Gd), cerium (Ce), bismuth (Bi), and yttrium (Yb).

[0010] In a preferred embodiment, in step one, the concentration of the rare earth nitric acid solution is 0.01~2.0 mol / L.

[0011] As a preferred embodiment, the multi-element doped metal oxide ceramic electrolyte precursor material and rare earth nitric acid solution are mixed at a solid-liquid mass ratio of 1.5% to 5% and then ultrasonically dispersed for a dispersion time of 5 to 30 minutes.

[0012] In a preferred embodiment, in step two, the modified precursor material is placed in a muffle furnace for calcination at a temperature of 400-700°C for 0.5-2 hours.

[0013] In a preferred embodiment, in step three, the shaped sheet is placed in a muffle furnace for baking at a temperature of 700~1000℃ for 8-24 hours.

[0014] As a preferred embodiment, the molding pressure is 15~25MPa and the molding time is 2~5min.

[0015] According to another aspect of the present invention, a high-entropy bismuth oxide-based electrolyte obtained by the above method is provided.

[0016] According to another aspect of the invention, the application of the high-entropy bismuth oxide-based electrolyte in a solid oxide fuel cell is provided.

[0017] This invention modifies multi-element-doped metal oxide ceramic electrolytic precursor materials prepared by traditional methods with rare earth nitric acid solutions (such as zirconium nitrate solution, neodymium nitrate solution, and yttrium nitrate solution), and obtains high-entropy electrolyte materials with high ion transport performance through ion exchange-forming calcination and other technical routes.

[0018] Compared with existing technologies, the high-entropy modification strategy provided by this invention improves the structural stability of electrolyte materials at different temperatures. By suppressing phase transitions through multi-element doping and precise control of ion types, concentrations and spatial distribution, the obtained electrolyte materials exhibit high ion transport performance at low and medium temperatures. Detailed Implementation

[0019] The basic concept of this invention is to use multi-element doped metal oxide ceramic electrolyte precursor materials as raw materials to prepare high-entropy electrolyte materials with high ion transport performance through the technical route of ion exchange-forming calcination.

[0020] A typical embodiment of the present invention provides a method for preparing a high-entropy bismuth oxide-based electrolyte, comprising the following steps.

[0021] Step 1: Ion exchange with rare earth nitric acid solution Rare earth nitric acid solution was thoroughly mixed and dispersed with multi-element doped metal oxide ceramic electrolyte precursor material, and the modified precursor material was obtained after centrifugation and drying.

[0022] The rare earth nitric acid solution is selected from one of zirconium nitrate, neodymium nitrate, and yttrium nitrate solutions.

[0023] The multi-element doped electrolyte precursor material described in this embodiment is prepared by traditional methods such as co-precipitation, sol-gel method, hydrothermal synthesis, and ball milling.

[0024] Preferably, the multi-element doped metal oxide ceramic electrolyte precursor material is prepared by uniformly dispersing, alkali-co-precipitating, and calcining heat treatment of a nitric acid solution containing lanthanum (La), praseodymium (Pr), samarium (Sm), gadolinium (Gd), cerium (Ce), bismuth (Bi), and yttrium (Yb).

[0025] Rare earth nitric acid solutions can be used at different concentrations, ranging from 0.01 to 2.0 mol / L, such as 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 1.0 mol / L, and 2.0 mol / L. Multi-element doped metal oxide ceramic electrolyte precursor powder materials are mixed and dispersed with rare earth nitric acid solutions at a solid-liquid mass ratio of 1.5% to 5%, such as 1.5%, 2%, 3.5%, 4%, 4.5%, and 5%. Preferably, the dispersion is performed ultrasonically under stirring conditions for 5 to 30 minutes.

[0026] Step 2, medium-low temperature roasting heat treatment The modified precursor material obtained in step one is calcined a second time, and the calcination temperature and time are controlled to transform it into a metal oxide precursor material.

[0027] Preferably, the modified precursor material is calcined in a muffle furnace at a temperature of 400-700°C for 0.5-2 hours. For example, calcination can be carried out at 400°C for 2 hours, 500°C for 1.5 hours, 600°C for 1 hour, 650°C for 1.5 hours, or 700°C for 0.5 hours.

[0028] Step 3: Molding and sintering to achieve high-entropy densification. Metal oxide precursor materials are pressed into tablets, and the tablets are then calcined. The calcination temperature and time are controlled to make them high-entropy densified, and then cooled to obtain dense high-entropy electrolyte materials.

[0029] Preferably, the metal oxide precursor powder material is placed in a tableting mold and pressed into tablets, with the molding pressure controlled at 15~25MPa and the molding time at 2~5min.

[0030] Preferably, the shaped sheet is placed in a muffle furnace and baked at a temperature of 700-1000℃ for 8-24 hours. For example, it is baked at 700℃ for 24 hours, 800℃ for 16 hours, 850℃ for 18 hours, 900℃ for 12 hours, or 1000℃ for 8 hours.

[0031] The technical solutions claimed in this invention will be further described below through some embodiments. However, the embodiments and comparative examples are for explaining the implementation schemes of this invention and do not exceed the scope of the subject matter of this invention. The scope of protection of this invention is not limited by the embodiments. Unless otherwise specified, the materials and reagents used in this invention can be obtained from commercially available products in the art. Example 1

[0032] In this embodiment, the multi-element doped metal oxide ceramic electrolyte precursor material with the chemical formula (Bi) is selected. 3 / 4 Pr 1 / 16 Sm 1 / 16 Gd 1 / 16 Yb 1 / 16 2O3 is obtained by the traditional co-precipitation method. The specific modification operation is as follows: Bismuth nitrate was mixed with nitrates corresponding to four elements—praseodymium (Pr), samarium (Sm), gadolinium (Gd), and yttrium (Yb)—in a stoichiometric ratio of 12:1:1:1:1 to prepare a nitrate mixed solution. The total metal ion concentration was controlled at 0.2 mol / L, and ammonia was added to maintain the final pH value of the system at 10.0. A precipitate was obtained and dried at 60℃ for 24 h to obtain a multi-element doped metal oxide ceramic electrolyte precursor material.

[0033] (1) 5g of the multi-element doped metal oxide ceramic electrolyte precursor material obtained by co-precipitation was mixed with 0.1mol / L zirconium nitrate solution at a solid-liquid mass ratio of 1.5% and ultrasonically dispersed for 5 minutes. After centrifugation, the precipitate was dried at 80℃ for 12h to obtain the modified precursor material.

[0034] (2) The modified precursor material is placed in a muffle furnace and calcined at 600°C for 1 hour to convert its hydroxide into metal oxide. The metal oxide precursor material obtained after calcination is then ground into powder.

[0035] (3) The powder is pressed into tablets by a tablet press, and the pressing pressure is controlled at 15 MPa and the pressing time is 2 min. The tablets are placed in a muffle furnace and calcined at 900℃ for 12 h to make them high-entropy and dense in structure, so as to obtain high-entropy bismuth oxide-based electrolyte. Example 2

[0036] The multi-element doped metal oxide ceramic electrolyte precursor material selected in this embodiment has the chemical formula ((Sm 0.25 Gd 0.25 Pr 0.25 Yb 0.25 ) 0.3 Bi 0.7 )2O3 was obtained by the sol-gel method, and the specific modification operation is as follows: Weigh 75 g of citric acid and dissolve it in 200 mL of deionized water. Stir until dissolved, then add ammonia to adjust the pH to 6. Control the total molar amount of metal ions to 0.02 mol, according to ((Sm 0.25 Gd 0.25 Pr 0.25 Yb 0.25 ) 0.3 Bi 0.7 The stoichiometric ratio of samarium (Sm), gadolinium (Gd), praseodymium (Pr), yttrium (Yb), and bismuth (Bi) nitrates were added and stirred to dissolve the mixture. The mixture was then heated and concentrated to form a gel. Finally, the gel was pre-calcined in a muffle furnace at 600 °C to obtain a multi-element doped metal oxide ceramic electrolyte precursor material.

[0037] (1) 4g of multi-element doped metal oxide ceramic electrolyte precursor material synthesized by sol-gel was mixed with 0.3mol / L zirconium nitrate solution at a solid-liquid mass ratio of 5%, stirred and ultrasonically dispersed for 10 minutes. After centrifugation, the precipitate was dried at 80℃ for 12h to obtain the modified precursor material. (2) The modified precursor material was placed in a muffle furnace and calcined at 650°C for 1.5 h to complete the transformation of hydroxide to metal oxide. The metal oxide precursor material obtained after calcination was ground into powder.

[0038] (3) The powder is pressed into tablets by a tablet press, and the pressing pressure is controlled at 25 MPa and the pressing time is 3 min. The tablets are placed in a muffle furnace and calcined at 850°C for 18 h to make them high-entropy and dense in structure, so as to obtain high-entropy bismuth oxide-based electrolyte. Example 3

[0039] In this embodiment, the multi-element doped metal oxide ceramic electrolyte precursor material with the chemical formula (Bi) is selected. 2 / 3 Pr 1 / 12 Sm 1 / 12 Gd 1 / 12 Ce 1 / 12 2O3 is obtained by the traditional co-precipitation method. The specific modification operation is as follows: Bismuth nitrate was mixed with nitrates corresponding to four elements—praseodymium (Pr), samarium (Sm), gadolinium (Gd), and cerium (Ce)—in a stoichiometric ratio of 8:1:1:1:1 to prepare a nitrate mixed solution. The total metal ion concentration was controlled at 0.2 mol / L, and ammonia was added to maintain the final pH value of the system at 9.0. A precipitate was obtained and dried at 60℃ for 24 h to obtain a multi-element doped metal oxide ceramic electrolyte precursor material.

[0040] (1) 5g of the multi-element doped metal oxide ceramic electrolyte precursor material obtained by co-precipitation was mixed with 0.01mol / L zirconium nitrate solution at a solid-liquid mass ratio of 2%, stirred and ultrasonically dispersed for 5 minutes. After centrifugation, the precipitate was dried at 80℃ for 12h to obtain the modified precursor material.

[0041] (2) The modified precursor material is placed in a muffle furnace and calcined at 400°C for 2 hours to convert its hydroxide into metal oxide. The metal oxide precursor material obtained after calcination is then ground into powder.

[0042] (3) The powder is pressed into tablets by a tablet press, and the pressing pressure is controlled at 15 MPa and the pressing time is 5 min. The tablets are placed in a muffle furnace and calcined at 700°C for 24 h to make them high-entropy and dense in structure, so as to obtain high-entropy bismuth oxide-based electrolyte. Example 4

[0043] The multi-element doped metal oxide ceramic electrolyte precursor material selected in this embodiment has the chemical formula ((Sm 0.25 Gd 0.25 Pr 0.25 Ce 0.25 ) 0.5 Bi 0.5 )2O3 was obtained by the sol-gel method, and the specific modification operation is as follows: Weigh 50 g of citric acid and dissolve it in 200 mL of deionized water. Stir until dissolved, then add ammonia to adjust the pH to 6. Control the total molar amount of metal ions to 0.02 mol, according to ((Sm 0.25 Gd 0.25 Pr 0.25 Ce 0.25 ) 0.5 Bi 0.5 The stoichiometric ratio of samarium (Sm), gadolinium (Gd), praseodymium (Pr), cerium (Ce), and bismuth (Bi) nitrates were added and stirred to dissolve the mixture. The mixture was then heated and concentrated to form a gel. Finally, the gel was pre-calcined in a muffle furnace at 600 °C to obtain a multi-element doped metal oxide ceramic electrolyte precursor material.

[0044] (1) 4g of multi-element doped metal oxide ceramic electrolyte precursor material synthesized by sol-gel was mixed with 2mol / L zirconium nitrate solution at a solid-liquid mass ratio of 3.5% and ultrasonically dispersed for 10 minutes. After centrifugation, the precipitate was dried at 80℃ for 12h to obtain the modified precursor material. (2) The modified precursor material is placed in a muffle furnace and calcined at 700°C for 0.5 h to complete the transformation of hydroxide to metal oxide. The metal oxide precursor material obtained after calcination is ground into powder.

[0045] (3) The powder is pressed into tablets by a tablet press, and the pressing pressure is controlled at 25 MPa and the pressing time is 2 min. The tablets are placed in a muffle furnace and calcined at 1000℃ for 8 h to make them high-entropy and dense in structure, so as to obtain high-entropy bismuth oxide-based electrolyte.

[0046] Comparative Example 1 According to (Bi) 3 / 4 Pr 1 / 16 Sm 1 / 16 Gd 1 / 16 Yb 1 / 16 The stoichiometric ratio of bismuth nitrate (2O3) was 12:1:1:1:1. 0.2 mol / L bismuth nitrate was mixed with nitrates corresponding to four elements: praseodymium (Pr), samarium (Sm), gadolinium (Gd), and yttrium (Yb) to prepare a nitrate mixed solution. Ammonia was added to control the final pH value of the system to maintain at 10.0, and a precipitate was obtained. The precipitate was dried at 60℃ for 24 h to obtain a multi-element doped metal oxide ceramic electrolyte precursor material.

[0047] The precursor material was transferred to an alumina crucible and placed in a muffle furnace for heat treatment at 600°C for 1 hour to complete the conversion of hydroxide to metal oxide.

[0048] The heat-treated metal oxide powder was pressed into tablets at a pressure of 15 MPa for 2 minutes. The tablets were then placed in a muffle furnace and calcined at 900°C for 12 hours to increase entropy and densify the structure, thus obtaining the electrolyte material.

[0049] The electrolyte materials obtained in Example 1 and Comparative Example 1 were evaluated for their ion transport performance using AC impedance spectroscopy after cooling. The test conditions were: temperature range 550-750℃, with tests conducted at 50℃ intervals, amplitude 50 mV, and frequency range 0.1-10MHz. An equivalent circuit was constructed based on the test results for fitting, and the ionic conductivity was calculated using the formula σ = L / (R·S), where L is the thickness of the electrolyte sheet (measured using vernier calipers), R is the charge transfer impedance obtained from the equivalent circuit fitting, and S is the effective conductive area. The results are shown in Table 1.

[0050] Table 1

[0051] Comparative Example 2 Weigh 75 g of citric acid and dissolve it in 200 mL of deionized water. Stir until dissolved, then add ammonia to adjust the pH to 6. Control the total molar amount of metal ions to 0.02 mol, according to ((Sm 0.25 Gd 0.25 Pr 0.25 Yb 0.25 ) 0.3 Bi 0.7The stoichiometric ratio of samarium (Sm), gadolinium (Gd), praseodymium (Pr), yttrium (Yb), and bismuth (Bi) nitrates were added and stirred to dissolve the mixture. The mixture was then heated and concentrated to form a gel. Finally, the gel was pre-calcined in a muffle furnace at 600 °C to obtain a multi-element doped metal oxide ceramic electrolyte precursor material.

[0052] (1) The precursor material is transferred to an alumina crucible and placed in a muffle furnace for heat treatment. The temperature is maintained at 650°C for 1.5 hours to complete the conversion of hydroxide to metal oxide.

[0053] (2) The heat-treated metal oxide powder was pressed with a molding pressure of 25 MPa for 3 min. The molded tablets were then placed in a muffle furnace and calcined at 850 °C for 18 h to increase entropy and densify the structure, thus obtaining the electrolyte material.

[0054] The electrolyte materials obtained in Example 2 and Comparative Example 2 were evaluated for their ion transport performance using AC impedance spectroscopy after cooling. The test conditions were: temperature range 550-750℃, with tests conducted at 50℃ intervals, amplitude 50 mV, and frequency range 0.1-10MHz. An equivalent circuit was constructed based on the test results for fitting, and the ionic conductivity was calculated using the formula σ = L / (R·S), where L is the thickness of the electrolyte sheet (measured using vernier calipers), R is the charge transfer impedance obtained from the equivalent circuit fitting, and S is the effective conductive area. The results are shown in Table 2.

[0055] Table 2

[0056] The specific embodiments described above illustrate the technical solution and beneficial effects of the present invention in detail. It should be understood that the above embodiments are not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-entropy bismuth oxide-based electrolyte, characterized in that, include: Step 1: The rare earth nitric acid solution is thoroughly mixed and dispersed with the multi-element doped metal oxide ceramic electrolyte precursor material, and then the modified precursor material is obtained after centrifugation and drying. Step 2: The modified precursor material obtained in Step 1 is calcined a second time, and the calcination temperature and time are controlled to convert it into a metal oxide precursor material. Step 3: Press the metal oxide precursor material obtained in Step 2 into a sheet, and then calcine the sheet, controlling the calcine temperature and time to achieve high entropy densification.

2. The method for preparing high-entropy bismuth oxide-based electrolyte according to claim 1, characterized in that: In step one, the rare earth nitric acid solution is selected from one of zirconium nitrate, neodymium nitrate, and yttrium nitrate solutions.

3. The method for preparing the high-entropy bismuth oxide-based electrolyte according to claim 1 or 2, characterized in that: In step one, the multi-element doped metal oxide ceramic electrolyte precursor material is prepared by uniformly dispersing, alkali co-precipitation, and calcination heat treatment of a nitric acid solution containing lanthanum (La), praseodymium (Pr), samarium (Sm), gadolinium (Gd), cerium (Ce), and bismuth (Bi).

4. The method for preparing high-entropy bismuth oxide-based electrolyte according to claim 3, characterized in that: In step one, the concentration of the rare earth nitric acid solution is 0.01~2.0 mol / L.

5. The method for preparing the high-entropy bismuth oxide-based electrolyte according to claim 4, characterized in that: Multi-element doped metal oxide ceramic electrolyte precursor material was mixed with rare earth nitric acid solution at a solid-liquid ratio of 1.5% to 15% and then ultrasonically dispersed for 5 to 30 minutes.

6. The method for preparing high-entropy bismuth oxide-based electrolyte according to claim 5, characterized in that: In step two, the modified precursor material is placed in a muffle furnace for calcination at a temperature of 400-700℃ for 0.5-2 h.

7. The method for preparing the high-entropy bismuth oxide-based electrolyte according to claim 1 or 6, characterized in that: In step three, the shaped sheet is placed in a muffle furnace for baking at a temperature of 700~1000℃ for 8-24 hours.

8. The method for preparing high-entropy bismuth oxide-based electrolyte according to claim 7, characterized in that: The molding pressure is 15~25MPa, and the molding time is 2~5min.

9. The high-entropy bismuth oxide-based electrolyte obtained by any one of claims 1-8.

10. The application of the high-entropy bismuth oxide-based electrolyte of claim 9 in a solid oxide fuel cell.

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