Solid oxide fuel cell LSCFNMC cathode material as well as preparation method and application of high-entropy doped sol-gel of solid oxide fuel cell LSCFNMC cathode material

Abstract

The invention discloses a solid oxide fuel cell LSCFNMC cathode material as well as a preparation method and application of high-entropy doped sol-gel of the solid oxide fuel cell LSCFNMC cathode material, and belongs to the technical field of SOFC solid oxide fuel cells. The chemical formula of the cathode material is La < 0.6 > Sr < 0.4 > Co < 0.2 > Fe < 0.2 > Ni < 0.2 > Mn < 0.2 > Cu < 0.2 > O < 3 >, the thermal expansion coefficient is 13.81 * 10 <-6 > K <-1 >, and the applicable temperature is 600-800 DEG C. The LSCFNMC cathode material has a thermal expansion coefficient better matched with that of a common YSZ electrolyte, the stability of the material is greatly enhanced, the performance of the LSCFNMC cathode material in long-time operation is far better than that of a traditional LSCF cathode material, and the LSCFNMC cathode material shows better electrochemical performance in the medium-high temperature range of 600-800 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of SOFC (Solid Oxide Fuel Cell) technology, specifically relating to a solid oxide fuel cell (LSCFNMC) cathode material and its high-entropy doped sol-gel preparation method and application. Background Technology

[0002] The Earth is currently facing a severe climate crisis. The global electricity structure heavily relies on thermal power generation, leading to a series of problems such as global warming. This necessitates a new demand for clean, low-carbon, flexible, and efficient energy. Among all new energy devices, solid oxide fuel cells (SOFCs) are a promising energy conversion system. They can directly and efficiently convert the chemical energy stored in fuels (hydrocarbons such as H2 and CH4) into electrical energy in an environmentally friendly manner, achieving an energy conversion efficiency of over 80%.

[0003] Traditional solid oxide fuel cells (SOFCs) use dense solid oxide as the electrolyte and operate at high temperatures ranging from 800°C to 1000°C. This high-temperature operating environment presents numerous challenges, including high system costs, slow start-up and shutdown processes, rapid performance degradation, poor thermal matching, insufficient mechanical stability under thermal cycling, and potential material diffusion and aging at high temperatures. These drawbacks severely limit the development of SOFC technology and its commercial application. In contrast, low- and medium-temperature SOFCs exhibit advantages such as better stability, rapid start-up, a wider selection of sealing materials, and lower costs. Therefore, developing low- and medium-temperature SOFC technology is crucial to overcome the limitations faced by traditional high-temperature SOFCs and to further advance the development and commercialization of solid oxide fuel cell technology.

[0004] Therefore, it is necessary to explore novel electrode materials with high electrochemical catalytic activity, structural and property stability in the medium temperature range of 600℃ to 800℃. Mixed ion-electron conductors with perovskite (ABO3) structure have been extensively studied as SOFC cathode materials.

[0005] Among the many cathode materials, LSCF (La) 1-x Sr x Co 1-y Fe y O 3-δAs a mixed ion-electron conductor (MIEC), LSCF is considered the preferred cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) due to its high electronic conductivity and good oxygen reduction reaction (ORR) catalytic activity. However, LSCF cathode materials also have some bottlenecks. First, its large coefficient of thermal expansion is incompatible with commonly used YSZ electrolytes, which may lead to the formation of an insulating phase at the interface, affecting cell performance. Second, LSCF exhibits poor stability during long-term operation, and the diffusion and enrichment of Sr ions increase cathode polarization losses. Furthermore, at lower operating temperatures, the oxygen ion conductivity of LSCF decreases, affecting its electrochemical performance. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention aims to provide a solid oxide fuel cell (LSCFNMC) cathode material, its high-entropy doped sol-gel preparation method, and its application. The invention employs a high-entropy doped sol-gel method to prepare a uniformly composed, high-performance LSCFNMC cathode material. This preparation method is simple, and the prepared B-site high-entropy doped LSCFNMC cathode material has a thermal expansion coefficient that is more compatible with commonly used YSZ electrolytes. This greatly enhances the material's stability, resulting in performance far exceeding that of traditional LSCF cathode materials during long-term operation. Furthermore, it exhibits better electrochemical performance in the medium-high temperature range of 600℃-800℃.

[0007] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a solid oxide fuel cell (LSCFNMC) cathode material, wherein the chemical formula of the solid oxide fuel cell (LSCFNMC) cathode material is La. 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 O3.

[0008] In one embodiment, the coefficient of thermal expansion of the cathode material of the solid oxide fuel cell (LSCFNMC) is 13.81 × 10⁻⁶. -6 K -1 .

[0009] In one embodiment, the applicable temperature for the solid oxide fuel cell (LSCFNMC) cathode material is 600°C-800°C.

[0010] The present invention also provides a method for preparing the above-mentioned solid oxide fuel cell (LSCFNMC) cathode material, comprising the following steps: S1: According to La0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 The required metal nitrate, composed of La(NO3)3·6H2O, Sr(NO3)2, Co(NO3)2·6H2O, Fe(NO3)3·9H2O, Ni(NO3)2·6H2O, Mn(NO3)2 and Cu(NO3)2·3H2O, is prepared by dissolving the metal nitrate in deionized water to obtain a nitric acid solution. Citric acid and ethylenediaminetetraacetic acid are used as complexing agents to dissolve the solution in the nitric acid solution. The pH is then adjusted to the set value using a pH adjuster, followed by water bath evaporation to obtain a gel. S2: The gel is subjected to evaporation and drying followed by heating to obtain precursor powder; S3: The precursor powder is subjected to wet ball milling, the deionized aqueous solution after wet ball milling is collected and dried, the dried product is ground and then sintered and kept warm to obtain the solid oxide fuel cell (LSCFNMC) cathode material.

[0011] In one embodiment, the mass ratio of the metal nitrate to deionized water is 1:20-40.

[0012] Furthermore, the mass ratio of metal nitrate to deionized water is 1:30.

[0013] In one embodiment, the molar ratio of citric acid, ethylenediaminetetraacetic acid, and the metal cation in the nitric acid solution is 1:1.5-1.8:1.

[0014] Furthermore, the molar ratio of citric acid, ethylenediaminetetraacetic acid, and the metal cation in the nitric acid solution is 1:1.5:1.

[0015] In one embodiment, the pH adjuster is an ammonia solution with a mass concentration of 28%-30%; the set pH value is 8.

[0016] In one embodiment, the temperature of the water bath evaporation treatment is 60-80℃, and the time of the water bath evaporation treatment is 8-12 h; the temperature of the evaporation drying is 60-80℃, and the time of the evaporation drying is 8-12 h; the temperature of the heat treatment is 300-400℃, and the time of the heat treatment is 4-5 h.

[0017] Furthermore, the water bath evaporation treatment is performed at a temperature of 70°C for 10 hours; the evaporation drying treatment is performed at a temperature of 70°C for 12 hours; and the heat treatment treatment is performed at a temperature of 300°C for 5 hours.

[0018] In one embodiment, the wet ball milling process is carried out at a rotation speed of 300-350 rpm / min for 8-10 h; the wet ball milling process involves clockwise rotation for 4-5 h and counterclockwise rotation for 4-5 h; the drying temperature is 60-80℃ for 5-8 h; the grinding time is 0.5-1 h; the sintering temperature is 1000℃ for 2-5℃ / min; and the holding time is 3-5 h.

[0019] Furthermore, the ball milling process is carried out at a rotation speed of 300 rpm / min for 10 hours; the ball milling process involves rotating clockwise for 5 hours and counterclockwise for 5 hours; the drying temperature is 70℃ for 6 hours; the grinding time is 0.5 hours; the sintering temperature is 1000℃, and the sintering heating rate is 2-5℃ / min; the holding time is 4 hours.

[0020] The present invention also provides an application of the above-described solid oxide fuel cell LSCFNMC cathode material in a solid oxide fuel cell cathode.

[0021] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a solid oxide fuel cell (LSCFNMC) cathode material. This material undergoes high-entropy doping of the B-sites of LSCF by incorporating Ni, Mn, and Cu elements, forming an equi-component high-entropy doping structure with Co and Fe. This material exhibits a high-entropy effect that stabilizes the crystal structure and enhances the metal-oxygen bond energy, thereby reducing the coefficient of thermal expansion (TEC). Specifically, high-entropy doping typically introduces multiple transition metals (such as Ni, Mn, Cu, Co, and Fe) into the B-sites to form a high-entropy perovskite structure. Due to the entropy stabilization effect, this structure reduces lattice distortion and thermal vibration amplitude, thus suppressing thermal expansion and lowering the TEC. Furthermore, the high-entropy doping elements possess higher metal-oxygen bond energies (ABE), making the BO6 octahedral structure more stable and reducing the tendency for lattice expansion at elevated temperatures. The TEC values ​​of the aforementioned LSCFNMC cathode material and conventional LSCF cathode materials are 13.81 × 10⁻⁶. -6 K -1 and 16.60×10 -6 K -1 The average coefficient of thermal expansion of GDC in the temperature range of 30℃-850℃ is 12.39×10.-6 K -1 The coefficient of thermal expansion of 8YSZ is approximately 10.5 × 10⁻⁶. -6 K -1 Therefore, compared with traditional LSCF cathode materials, the LSCFNMC cathode material provided by this invention has a TEC value that is more compatible with the electrolyte and a thermal expansion coefficient that is more compatible with commonly used YSZ electrolytes. This greatly enhances the stability of the material, resulting in performance far exceeding that of traditional LSCF cathode materials during long-term operation. Furthermore, due to the structural changes brought about by high-entropy doping, LSCFNMC has more oxygen vacancies, more active crystal facets, and better oxygen ion conduction activity, exhibiting better electrochemical performance in the medium-high temperature range of 600℃-800℃: a maximum power density of 1.6 W·cm⁻¹. -2 Furthermore, it can work stably for a long time. The high-entropy doping approach of this material is novel and perfectly matches the sol-gel method for cathode preparation, which is simple to implement. Attached Figure Description

[0022] Figure 1 This is a flowchart of a method for preparing a high-entropy doped sol-gel for a solid oxide fuel cell (LSCFNMC) cathode material according to the present invention. Figure 2 This is a flowchart illustrating a method for preparing a high-entropy doped sol-gel system for a solid oxide fuel cell (LSCFNMC) cathode material, as provided in an embodiment of the present invention. Figure 3 The diagram shows a comparison of the electrochemical performance of the solid oxide fuel cell LSCFNMC cathode material obtained in Example 1 with that of the conventional LSCF cathode material; (a) IVP spectrum of LSCF single cell at 600-800℃; (b) IVP spectrum of LSCFNMC single cell at 600-800℃; (c) EIS spectrum of LSCF single cell at 600-800℃; (d) EIS spectrum of LSCFNMC single cell at 600-800℃. Detailed Implementation

[0023] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0024] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0025] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0026] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0027] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0028] While current sol-gel methods for preparing LSCF cathode materials exhibit high electronic conductivity and good oxygen reduction reaction (ORR) catalytic activity, they also face several bottlenecks. First, their high coefficient of thermal expansion is incompatible with commonly used YSZ electrolytes, potentially leading to the formation of an insulating phase at the interface and affecting battery performance. Second, LSCF exhibits poor stability during long-term operation; the diffusion and enrichment of Sr ions increase cathode polarization losses. Furthermore, at lower operating temperatures, the oxygen ion conductivity of LSCF decreases, impacting its electrochemical performance.

[0029] To address the aforementioned technical problems, this invention provides a solid oxide fuel cell (LSCFNMC) cathode material, its high-entropy doped sol-gel preparation method, and its applications.

[0030] One aspect provides a solid oxide fuel cell (LSCFNMC) cathode material with the chemical formula La. 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 O3 has a coefficient of thermal expansion of 13.81 × 10⁻⁶. -6 K -1 Suitable for temperatures between 600℃ and 800℃.

[0031] like Figure 1 As shown, the present invention also provides a method for preparing the above-mentioned solid oxide fuel cell (LSCFNMC) cathode material, as follows: S1: According to La 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 The required metal nitrate, composed of La(NO3)3·6H2O, Sr(NO3)2, Co(NO3)2·6H2O, Fe(NO3)3·9H2O, Ni(NO3)2·6H2O, Mn(NO3)2 and Cu(NO3)2·3H2O, is prepared by dissolving the metal nitrate in deionized water to obtain a nitric acid solution. Citric acid and ethylenediaminetetraacetic acid are used as complexing agents to dissolve the solution in the nitric acid solution. The pH is then adjusted to the set value using a pH adjuster, followed by water bath evaporation to obtain a gel. S2: The gel is subjected to evaporation and drying followed by heating to obtain precursor powder; S3: The precursor powder is subjected to wet ball milling, the deionized aqueous solution after wet ball milling is collected and dried, the dried product is ground and then sintered and kept warm to obtain the solid oxide fuel cell (LSCFNMC) cathode material.

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0034] The high-entropy doped sol-gel method preparation process of the solid oxide fuel cell (LSCFNMC) cathode material provided in the following examples is detailed in the appendix. Figure 2 Furthermore, the sol-gel method provided by this preparation method can prepare La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O3 (LSCF) and its B-site doped cathode material La 0.6 Sr 0.4 Co0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 O3(LSCFNMC).

[0035] The reagents used in the preparation of LSCFNMC cathode materials by the sol-gel method in the following examples include La(NO3)3·6H2O (AR, Sinopharm Holdings), Sr(NO3)2 (AR, Sinopharm Holdings), Co(NO3)2·6H2O (AR, Sinopharm Holdings), Fe(NO3)3·9H2O (AR, Sinopharm Holdings), Ni(NO3)2·6H2O (AR, Sinopharm Holdings), Mn(NO3)2 (AR, Sinopharm Holdings), and Cu(NO3)2·3H2O (AR, Sinopharm Holdings).

[0036] Example 1: This embodiment provides a solid oxide fuel cell (LSCFNMC) cathode material with the chemical formula La. 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 O3. The cathode material of this solid oxide fuel cell (LSCFNMC) has a uniform composition and high performance.

[0037] The specific steps of this preparation method are as follows: S1: According to La 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2To obtain the stoichiometric ratio of O3, the required metal nitrate, composed of La(NO3)3·6H2O, Sr(NO3)2, Co(NO3)2·6H2O, Fe(NO3)3·9H2O, Ni(NO3)2·6H2O, Mn(NO3)2, and Cu(NO3)2·3H2O, is dissolved in an appropriate amount of deionized water to prepare a nitric acid solution. The mass ratio of metal nitrate to deionized water is 1:30. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) are used as complexing agents to dissolve CA and EDTA (with a molar ratio of CA and EDTA to the metal cation of 1:1.5:1) in the nitric acid solution. Then, ammonia solution (NH3·H2O) is added dropwise with the aid of a magnetic stirrer and a pH meter until the pH of the solution is adjusted to 8. The solution is then placed in a water bath for evaporation, maintaining a constant temperature of 70°C throughout the evaporation process for approximately 10 minutes. A smooth gel forms after h; S2: The gel was placed in a 70°C forced-air drying oven to evaporate and dry the moisture for 12 h; the evaporated and dried gel was then placed in a box furnace at 300°C and heated for 5 h to obtain the precursor powder. S3: The precursor was ball-milled using a PULVERIZER 80 planetary ball mill at 300 rpm / min for 10 h to enhance its structural uniformity, including 5 h of clockwise rotation and 5 h of counterclockwise rotation to achieve complete physical grinding of the powder and enhance its structural uniformity. Then, the deionized water solution in the ball mill jar was collected into a glass evaporating dish and dried in a 70℃ constant temperature forced-air drying oven for 6 h. The dried mixture sample was then poured into an agate mortar and ground for 0.5 h. After thorough grinding, the sample was placed in a box furnace for sintering at a temperature of 1000℃, a heating rate of 2-5℃ / min, and a holding time of 4 h to obtain the desired LSCFNMC cathode perovskite structure powder material.

[0038] In this embodiment, the purity of the deionized water used is (>99.9%); the mass ratio of metal nitrate to deionized water is 1:30; the ball mill is a PULVERIZER 80 planetary ball mill with a working voltage of 220 V; the sintering temperature of the box furnace is 1000℃, the heating rate is 2-5℃ / min, and the holding time is 3 h.

[0039] The particle diameter of the LSCFNMC cathode perovskite structure powder material prepared in this embodiment and the LSCF material prepared in the same manner as in this embodiment are both approximately 150 nm.

[0040] Example 2: This embodiment provides a solid oxide fuel cell (LSCFNMC) cathode material with the chemical formula La. 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 O3.

[0041] The specific steps of this preparation method are as follows: S1: According to La 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 To obtain the stoichiometric ratio of O3, the required metal nitrate, composed of La(NO3)3·6H2O, Sr(NO3)2, Co(NO3)2·6H2O, Fe(NO3)3·9H2O, Ni(NO3)2·6H2O, Mn(NO3)2, and Cu(NO3)2·3H2O, is dissolved in an appropriate amount of deionized water to prepare a nitric acid solution. The mass ratio of metal nitrate to deionized water is 1:20. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) are used as complexing agents to dissolve CA and EDTA (with a molar ratio of CA and EDTA to the metal cation of 1:1.5:1) in the nitric acid solution. Then, ammonia solution (NH3·H2O) is added dropwise with the aid of a magnetic stirrer and a pH meter until the pH of the solution is adjusted to 8. The solution is then placed in a water bath for evaporation, maintaining a constant temperature of 60°C throughout the evaporation process. A smooth gel forms after h; S2: The gel was placed in a 60°C forced-air drying oven to evaporate and dry the moisture for 8 hours; the evaporated and dried gel was then placed in a box furnace at 300°C and heated for 4 hours to obtain the precursor powder. S3: The precursor was ball-milled using a PULVERIZER 80 planetary ball mill at 350 rpm / min for 8 hours to enhance its structural uniformity, including 4 hours of clockwise rotation and 4 hours of counterclockwise rotation to achieve complete physical grinding of the powder and enhance its structural uniformity. Then, the deionized aqueous solution in the ball mill jar was collected into a glass evaporating dish and dried in a 60℃ constant temperature forced-air drying oven for 5 hours. The dried mixture sample was then poured into an agate mortar and ground for 1 hour. After thorough grinding, the sample was placed in a box furnace for sintering at a temperature of 1000℃, a heating rate of 2-5℃ / min, and a holding time of 3 hours to obtain the desired LSCFNMC cathode perovskite structure powder material.

[0042] Example 3: This embodiment provides a solid oxide fuel cell (LSCFNMC) cathode material with the chemical formula La. 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 O3.

[0043] The specific steps of this preparation method are as follows: S1: According to La 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 To obtain the stoichiometric ratio of O3, the required metal nitrate, composed of La(NO3)3·6H2O, Sr(NO3)2, Co(NO3)2·6H2O, Fe(NO3)3·9H2O, Ni(NO3)2·6H2O, Mn(NO3)2, and Cu(NO3)2·3H2O, is dissolved in an appropriate amount of deionized water to prepare a nitric acid solution. The mass ratio of metal nitrate to deionized water is 1:40. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) are used as complexing agents to dissolve CA and EDTA (with a molar ratio of CA and EDTA to the metal cation of 1:1.8:1) in the nitric acid solution. Then, ammonia solution (NH3·H2O) is added dropwise with the aid of a magnetic stirrer and a pH meter until the pH of the solution is adjusted to 8. The solution is then placed in a water bath for evaporation, maintaining a constant temperature of 80°C throughout the evaporation process for approximately 12 hours. A smooth gel forms after h; S2: The gel was placed in an 80°C forced-air drying oven to evaporate and dry the moisture for 12 h; the evaporated and dried gel was then placed in a box furnace at 400°C and heated for 5 h to obtain the precursor powder. S3: The precursor was ball-milled using a PULVERIZER 80 planetary ball mill at 300 rpm / min for 10 h to enhance its structural uniformity, including 5 h of clockwise rotation and 5 h of counterclockwise rotation to achieve complete physical grinding of the powder and enhance its structural uniformity. Then, the deionized water solution in the ball mill was collected into a glass evaporating dish and dried in an 80℃ constant temperature forced-air drying oven for 8 h. The dried mixture sample was then poured into an agate mortar and ground for 0.5 h. After thorough grinding, the sample was placed in a box furnace for sintering at a temperature of 1000℃, a heating rate of 2-5℃ / min, and a holding time of 5 h to obtain the desired LSCFNMC cathode perovskite structure powder material.

[0044] The coefficient of thermal expansion was analyzed using a thermogravimetric analyzer (TG 209 F3) with a temperature range of 25-900℃.

[0045] The TEC values ​​of LSCF and LSCFNMC obtained in Example 1 were 16.60 × 10⁻⁶. -6 K -1 and 13.81×10 -6 K -1 .

[0046] The process of assembling a single cell using LSCFNMC cathode material is as follows: The single-cell structure is NiO-YSZ|YSZ|GDC|LSCFNMC, where the anode support is NiO-YSZ, the electrolyte is YSZ, and the barrier layer is GDC. First, a dense NiO-YSZ anode support sheet was prepared using a co-compression method. The die diameter for pressing was 15 mm, and the NiO-YSZ mixed powder was compressed into 15 mm anode support discs using a compressor at a pressure of 200 MPa for 5 minutes. Then, the anode support discs were sintered in a box furnace at 1400 °C for 5 hours. The sintered discs were polished with sandpaper to obtain an anode support disc with a thickness of approximately 300 μm. Next, YSZ electrolyte powder was mixed with a small amount of plasticizers and sintering aids such as NiO, DOP, PEG, and TEA in an ethanol solution to prepare an electrolyte slurry. This slurry was then screen-printed onto one side of a NiO-YSZ anode support disc. The disc was then sintered in a box furnace at 1400℃ for 2 hours to obtain a NiO-YSZ|YSZ disc. Finally, GDC (Gd) was used to... 0.1Ce 0.9 O 1.95 As a barrier layer, GDC was mixed with a binder prepared from turpentine alcohol and 10% by mass of ethyl cellulose to form a GDC slurry, which was then screen-printed onto the YSZ electrolyte side of the NiO-YSZ|YSZ disc. After drying, the GDC slurry was calcined in air at 1200°C for 5 hours. The LSCFNMC cathode slurry was prepared using the same process as the GDC slurry. Finally, the LSCFNMC cathode slurry was coated onto the outside of the GDC barrier layer and calcined in air at 1000°C for 2 hours to obtain a cathode active area of ​​approximately 0.64 cm². 2 A full battery.

[0047] The assembly process for a single cell using LSCF cathode material is the same as described above.

[0048] The electrochemical performance of the high-entropy doped sol-gel method-prepared uniform and high-performance solid oxide fuel cell (LSCFNMC) cathode material obtained in Example 1 was tested, and the results were compared with those of traditional LSCF cathode materials. (See attached figures.) Figure 3 As shown.

[0049] from Figure 3 As shown in (a), (b), (c), and (d), the LSCFNMC exhibits the highest peak power density (PPD) of 1604.37 mW·cm at a test temperature of 800℃. -2 The LSCF exhibited the highest peak power density (PPD) of 1137.85 mW·cm at a test temperature of 800℃. -2 Comparative analysis revealed that the single cell assembled with an LSCFNMC cathode after high-entropy doping with multiple active elements exhibited a peak power density (PPD) approximately 1.4 times higher than that assembled with a conventional LSCF cathode. Within the test temperature range of 600–800 °C, the impedance of both single cells decreased with increasing temperature; however, the LSCFNMC cathode consistently showed a significantly lower impedance than the LSCF cathode at every test temperature. For example, at 800 °C, the total resistance of the LSCFNMC was 0.44 Ω cm⁻¹. 2 The ohmic resistance is 0.13 Ω cm. 2 The polarization resistance is 0.31 Ω cm. 2 In contrast, the total resistance of the LSCF is 0.62 Ω cm. 2 The ohmic resistance is 0.19 Ωcm. 2 The polarization resistance is 0.43 Ω cm. 2 Therefore, the LSCFNMC cathode material synthesized in this invention exhibits superior electrochemical performance compared to traditional LSCF.

[0050] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A cathode material for a solid oxide fuel cell (LSCFNMC), characterized in that, The chemical formula of the cathode material of the solid oxide fuel cell LSCFNMC is La. 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 O3.

2. The solid oxide fuel cell (LSCFNMC) cathode material according to claim 1, characterized in that, The coefficient of thermal expansion of the cathode material in the solid oxide fuel cell LSCFNMC is 13.81 × 10⁻⁶. -6 K -1 .

3. The solid oxide fuel cell (LSCFNMC) cathode material according to claim 1, characterized in that, The applicable temperature range for the cathode material of the solid oxide fuel cell LSCFNMC is 600℃-800℃.

4. A method for preparing the solid oxide fuel cell (LSCFNMC) cathode material according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1: According to La 0.6 Sr 0.4 Co 0.2 Fe 0.2 Ni 0.2 Mn 0.2 Cu 0.2 The required metal nitrate, composed of La(NO3)3·6H2O, Sr(NO3)2, Co(NO3)2·6H2O, Fe(NO3)3·9H2O, Ni(NO3)2·6H2O, Mn(NO3)2 and Cu(NO3)2·3H2O, is prepared by dissolving the metal nitrate in deionized water to obtain a nitric acid solution. Citric acid and ethylenediaminetetraacetic acid are used as complexing agents to dissolve the solution in the nitric acid solution. The pH is then adjusted to the set value using a pH adjuster, followed by water bath evaporation to obtain a gel. S2: The gel is subjected to evaporation and drying followed by heating to obtain precursor powder; S3: The precursor powder is subjected to wet ball milling, the deionized aqueous solution after wet ball milling is collected and dried, the dried product is ground and then sintered and kept warm to obtain the solid oxide fuel cell (LSCFNMC) cathode material.

5. The method for preparing the solid oxide fuel cell (LSCFNMC) cathode material according to claim 4, characterized in that, The mass ratio of the metal nitrate to deionized water is 1:20-40.

6. The method for preparing the cathode material of a solid oxide fuel cell (LSCFNMC) according to claim 4, characterized in that, The molar ratio of citric acid, ethylenediaminetetraacetic acid, and the metal cation in the nitric acid solution is 1:1.5-1.8:

1.

7. The method for preparing the cathode material of a solid oxide fuel cell (LSCFNMC) according to claim 4, characterized in that, The pH adjuster is an ammonia solution with a mass concentration of 28%-30%; the set pH value is 8.

8. The method for preparing the cathode material of a solid oxide fuel cell (LSCFNMC) according to claim 4, characterized in that, The water bath evaporation treatment is carried out at a temperature of 60-80℃ for 8-12 hours; the evaporation drying treatment is carried out at a temperature of 60-80℃ for 8-12 hours; and the heat treatment treatment is carried out at a temperature of 300-400℃ for 4-5 hours.

9. The method for preparing the cathode material of a solid oxide fuel cell (LSCFNMC) according to claim 4, characterized in that, The wet ball milling process is carried out at a speed of 300-350 rpm / min for 8-10 h; the wet ball milling process involves clockwise rotation for 4-5 h and counterclockwise rotation for 4-5 h; the drying temperature is 60-80℃ for 5-8 h; the grinding time is 0.5-1 h; the sintering temperature is 1000℃ with a heating rate of 2-5℃ / min; and the holding time is 3-5 h.

10. The application of the solid oxide fuel cell LSCFNMC cathode material as described in any one of claims 1 to 3 in the cathode of a solid oxide fuel cell.

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