Fuel cell cathode material for improving chromium resistance, preparation method and application

Abstract

The invention particularly relates to a fuel cell cathode material for improving chromium resistance, a preparation method and application, and belongs to the field of solid oxide fuel cells. A large-scale SOFC (Solid Oxide Fuel Cell) generally adopts a chromium-containing alloy as a metal interconnection material and has certain toxicity to the cathode, the element fluorine is adopted to partially replace the O site of the SrCo < 0.9 > Ta0. 1O < 3-delta > material to prepare the SrCo < 0.9 > Ta0. 1O < 3-delta > Fx (SCTFx, x = 0.05-0.2) material, and the chromium resistance of the cathode of the medium-temperature solid oxide cell is improved. In addition, the cathode material is simple in preparation process, excellent in performance and good in industrialization prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid oxide fuel cells, and in particular relates to a fuel cell cathode material with improved chromium resistance and a preparation method thereof, and application of the cathode material in the field of solid oxide fuel cells. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Solid Oxide Fuel Cell (SOFC) is an all-solid-state energy conversion device that directly converts chemical energy in fuel into electrical energy. It has the advantages of high energy conversion efficiency, safety, and environmental friendliness. However, since large SOFC stacks usually use chromium-containing alloys as metal interconnect materials, chromium oxide will form on its surface at high temperatures, which will then react with air or water vapor to form chromium vapor, causing chromium poisoning of the cathode material and leading to SOFC performance degradation. Therefore, the development of cathode materials with high chromium resistance is of great significance to the engineering application of SOFC.

[0004] At present, the mainstream cathode materials for SOFC are mainly perovskite-type mixed ionic-electronic conductor (MIEC) oxides, such as single perovskite, double perovskite and Ruddlesden-Popper structure perovskite materials. As a typical single perovskite MIEC oxide, SrCo 0.9 Ta 0.1 O 3-δ The material has excellent catalytic activity in the medium temperature range and is therefore widely used as a cathode material. However, under long-term operating conditions, the alkaline earth element Sr tends to segregate and aggregate on the cathode surface and react with the chromium vapor on the surface of the interconnect material to generate an inert phase, which is not conducive to the performance of the SOFC stack.

[0005] The present invention believes that it is of great significance to develop SOFC cathode materials with excellent chromium resistance under long-term operating conditions. Summary of the invention

[0006] In order to overcome the deficiencies in the prior art and improve the tolerance of the cathode material to chromium, the present invention associates the doping of part of the fluorine element into the perovskite oxide to achieve tolerance to the chromium environment. The present invention verifies that the introduction of the fluorine element reduces the secondary phase formation on the surface of the perovskite material and effectively improves the stability of the cathode material. In addition, the introduction of the fluorine element also effectively reduces the growth of the polarization resistance of the half-cell in a chromium-containing atmosphere and improves the chromium resistance of the cathode material.

[0007] Based on the above achievements, the present invention provides the following technical solutions: In a first aspect of the present invention, a fuel cell cathode material with improved chromium resistance is provided, wherein the composition of the cathode material is as follows: SrCo 0.9 Ta 0.1 O 3-δ F x (x=0.05~0.2) (SCTF for short), where δ is the value to ensure the electrical neutrality of the material; its XRD diffraction spectrum contains 2 θ The X-ray diffraction peaks are at 33.00±0.1, 40.64±0.1, 47.20±0.1, 58.60±0.1, 68.70±0.1, and 78.12±0.1.

[0008] In a second aspect, the present invention provides a method for preparing the cathode material according to the first aspect, comprising the following steps: 0.9 Ta 0.1 O 3-δ F x Strontium carbonate (SrCO3), cobalt trioxide (Co3O4), tantalum pentoxide (Ta2O5), and strontium fluoride (SrF2) are weighed respectively in the ratio of the corresponding chemical element stoichiometric numbers in (x=0.05~0.2), ball-milled by wet grinding, and then dried, pressed into tablets, and calcined to obtain the obtained product.

[0009] The preparation method of the second aspect also has the following preferred implementation modes: The ball milling process preferably uses an organic reagent as a solvent, an example of which is ethanol; the ball milling speed is 220-260 r / min, and the time is 10-14 h.

[0010] The above-mentioned drying process can adopt heat radiation drying, and the drying temperature does not exceed 180°C. The further preferred drying temperature is 140-160°C, and the drying time is 0.8-1.5h.

[0011] The tableting is achieved by a tablet press, the dried powder is placed at a pressure of 280-320 MPa for 100-150 seconds to obtain a dense tablet, and the dense tablet is calcined at 1000-1200°C for 8-12 hours to obtain SrCo 0.9 Ta 0.1 O 3-δ F x Material.

[0012] In a third aspect of the present invention, a half-cell is provided, the half-cell comprising the cathode material according to the first aspect, and also comprising a solid electrolyte, the solid electrolyte being selected from La 0.9 Sr 0.1 Ga0.8 Mg 0.2 O3(LSGM), Sm 0.2 Ce 0.8 O 1.9 (SDC), Ce 0.9 G 0.1 O 1.95 (GDC) or a combination of these.

[0013] The fourth aspect of the present invention provides a method for preparing the half-cell described in the third aspect, comprising the following steps: wet-milling the cathode material described in the first aspect to obtain a powder, mixing the powder with an organic binder to form a cathode slurry, uniformly coating the cathode slurry on the surface of a solid electrolyte, and calcining the slurry after drying.

[0014] In the preparation method of the fourth aspect, the ball milling process preferably uses an organic reagent to disperse the cathode material, such as ethanol, and the ball milling speed is 220~260 r / min, and the time is 22~26h; since the cathode material prepared by the method described in the second aspect is a dense sheet, the dense sheet can be pre-processed into a powder by grinding or the like before being added to the ball mill to make it better soluble in the above-mentioned organic solvent.

[0015] The above-mentioned organic binder is an ethyl cellulose pine alcohol binder, wherein the mass ratio of ethyl cellulose to pine alcohol is 1:12-19, and further ratios can be routinely adjusted by technicians in this field according to usage requirements; and the mass ratio of cathode material powder to organic binder is 1:1-2.

[0016] The coating can be achieved by a screen printing machine, and after drying, the half-cell with the cathode material is obtained by calcining at 800-1200° C. for 1-3 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The cathode material (SCTF) prepared by the present invention is a new cathode material with the characteristics of simple composition and simple synthesis process. In addition, since the F- with higher electronegativity occupies the oxygen vacancies, the valence state of the metal ions in the perovskite increases, and its acidity increases, which can effectively improve the chromium resistance of the material.

[0018] 2. It has been verified by the present invention that the battery with SCTF cathode exhibits excellent chromium resistance compared with the battery with SCT cathode and can work stably in a chromium-containing atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 XRD diagrams of cathode materials in Examples 1 to 3 and Comparative Examples; in, Figure 1 (a) is the XRD pattern of the cathode materials in Examples 1 to 3 and the comparative example; Figure 1 (b) is Figure 1 2 of (a) θ It is the enlarged view of the main peak at 33.00±0.1; Figure 2 The SEM images of the dense samples of Examples 1 to 3 and the comparative example after being treated in a chromium-containing atmosphere at 700° C. for 24 hours; in, Figure 2 (a) is a SEM image of the dense sample in the comparative example after being treated in a chromium-containing atmosphere at 700°C for 24 hours; Figure 2 (b) is a SEM image of the dense sample in Example 1 after being treated in a chromium-containing atmosphere at 700° C. for 24 hours; Figure 2 (c) is a SEM image of the dense sample in Example 2 after being treated in a chromium-containing atmosphere at 700° C. for 24 hours; Figure 2 (d) is a SEM image of the dense sample in Example 3 after being treated in a chromium-containing atmosphere at 700° C. for 24 hours; Figure 3 XRD patterns of the dense samples of Examples 1 to 3 and the comparative example after being treated in a chromium-containing atmosphere at 700° C. for 24 hours; in, Figure 3 (a) is the XRD pattern of the dense samples of Examples 1 to 3 and the comparative example after being treated in a chromium-containing atmosphere at 700° C. for 24 hours; Figure 3 (b) is Figure 3 2 of (a) θ This is an enlarged view of segments 24 to 30; Figure 4 The AC impedance spectra of the half-cells based on the cathode materials of Examples 1 to 3 and the comparative example are tested at 700° C. in a chromium-containing atmosphere for 22 hours and change with time; in, Figure 4 (a) is the AC impedance spectrum of the half-cell in the comparative example, which changes with time when tested in a chromium-containing atmosphere at 700°C for 22 hours; Figure 4 (b) is the AC impedance spectrum of the half-cell in Example 1 that changes with time when tested in a chromium-containing atmosphere at 700° C. for 22 hours; Figure 4(c) is the AC impedance spectrum of the half-cell in Example 2 that changes with time when tested in a chromium-containing atmosphere at 700° C. for 22 hours; Figure 4 (d) is the AC impedance spectrum of the half-cell in Example 3 that changes with time when tested in a chromium-containing atmosphere at 700° C. for 22 hours. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] Terminology explanation: SCTF: the fuel cell cathode material with improved chromium resistance according to the first aspect of the present invention, the composition of the material is shown in the following formula: SrCo 0.9 Ta 0.1 O 3-δ F x (x=0.05~0.2), referred to as SCTF.

[0024] SCT: The single perovskite type MIEC oxide without fluorine element provided in the comparative example of the present invention has the chemical formula of SrCo 0.9 Ta 0.1 O 3-δ , referred to as SCT.

[0025] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in combination with specific embodiments and comparative examples.

[0026] Example 1 In this embodiment, a fuel cell cathode material with improved chromium resistance and a corresponding half-cell are provided. The cathode material has a structural formula of SrCo 0.9 Ta 0.1 O 3-δ F 0.05 , the preparation method comprises the following steps: (1) According to the chemical formula SrCo 0.9 Ta 0.1 O3-δ F 0.05 Weigh SrCO3, Co3O4, Ta2O5, and SrF2 in the ratio of the stoichiometric number of the corresponding chemical elements, and then dissolve each raw material in a ball mill containing ethanol in turn; (2) placing the ball mill obtained in step (1) in a ball mill and ball milling at a speed of 240 r / min for 12 h; (3) The ball-milled solution was placed in an oven and treated at 150°C for 1 h to obtain a mixed powder; (4) Using a tablet press, the mixed powder of step (3) was placed under a pressure of 300 MPa for 120 s to obtain a dense tablet, and then calcined at 1100 °C for 10 h to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Material.

[0027] In this embodiment, a SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The cathode half-cell is prepared as follows: S1. Sm 0.2 Ce 0.8 O 1.9 (SDC) powder was used as electrolyte, and the electrolyte was obtained through tableting and calcination process; S2. SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The dense slices were manually ground for 30 min to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The powder was dissolved in a ball mill containing ethanol and milled in a ball mill at 240 r / min for 24 h to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Cathode powder; S3. The SrCo obtained in S2 0.9 Ta 0.1 O 3-δ F 0.05 The cathode powder and ethyl cellulose-terpineol (ethyl cellulose mass fraction 7%) were ground and mixed evenly at a mass ratio of 1:1.5 to prepare a cathode slurry; S4. The cathode slurry obtained in S3 is evenly coated on the surface of the electrolyte prepared in step S1 by a screen printer, and after drying, it is calcined at 1000°C for 2 h to obtain a SrCo0.9 Ta 0.1 O 3-δ F 0.05 Cathode half-cell.

[0028] Example 2 In this embodiment, another fuel cell cathode material with improved chromium resistance and a corresponding half-cell are provided. The difference from Embodiment 1 is that the cathode material has a structural formula of SrCo 0.9 Ta 0.1 O 3-δ F 0.10 , according to the chemical formula SrCo 0.9 Ta 0.1 O 3-δ F 0.10 SrCO3, Co3O4, Ta2O5, and SrF2 are weighed respectively according to the ratio of the stoichiometric numbers of the corresponding chemical elements, and then the raw materials are dissolved in turn into a ball mill containing ethanol. The other steps and the corresponding half-cell preparation steps are the same as those in Example 1.

[0029] Example 3 In this embodiment, another fuel cell cathode material with improved chromium resistance and a corresponding half-cell are provided. The difference from Embodiment 1 is that the cathode material has a structural formula of SrCo 0.9 Ta 0.1 O 3-δ F 0.20 , according to the chemical formula SrCo 0.9 Ta 0.1 O 3-δ F 0.20 SrCO3, Co3O4, Ta2O5, and SrF2 are weighed respectively according to the ratio of the stoichiometric numbers of the corresponding chemical elements, and then the raw materials are dissolved in turn into a ball mill containing ethanol. The other steps and the corresponding half-cell preparation steps are the same as those in Example 1.

[0030] Example 4 In this embodiment, another fuel cell cathode material with improved chromium resistance is provided, the structural formula of which is SrCo 0.9 Ta 0.1 O 3-δ F 0.05 , the preparation method comprises the following steps: (1) According to the chemical formula SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Weigh SrCO3, Co3O4, Ta2O5, and SrF2 in the ratio of the stoichiometric number of the corresponding chemical elements, and then dissolve each raw material in a ball mill containing ethanol in turn; (2) placing the ball mill obtained in step (1) in a ball mill and ball milling at a speed of 220 r / min for 14 h; (3) The ball-milled solution was placed in an oven and treated at 140°C for 1.5 h to obtain a mixed powder; (4) Using a tablet press, the mixed powder of step (3) was placed under a pressure of 320 MPa for 100 s to obtain a dense tablet, and then calcined at 1000 °C for 12 h to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Material.

[0031] In this embodiment, a SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The cathode half-cell is prepared as follows: S1. Sm 0.2 Ce 0.8 O 1.9 (SDC) powder was used as electrolyte, and the electrolyte was obtained through tableting and calcination process; S2. SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The dense slices were manually ground for 30 min to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The powder was dissolved in a ball mill containing ethanol and milled in a ball mill at 220 r / min for 26 h to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Cathode powder; S3. The SrCo obtained in S2 0.9 Ta 0.1 O 3-δ F 0.05 The cathode powder and ethyl cellulose-terpineol (the mass fraction of ethyl cellulose is 6.5%) are fully ground and mixed in a ratio of 1:1 to prepare a cathode slurry; S4. The cathode slurry obtained in S3 is evenly coated on the surface of the electrolyte prepared in step S1 by a screen printer, and after drying, it is calcined at 800°C for 3 h to obtain a SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Cathode half-cell.

[0032] Example 5 In this embodiment, another fuel cell cathode material with improved chromium resistance is provided, the structural formula of which is SrCo 0.9 Ta 0.1 O 3-δ F 0.05 , the preparation method comprises the following steps: (1) According to the chemical formula SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Weigh SrCO3, Co3O4, Ta2O5, and SrF2 in the ratio of the stoichiometric number of the corresponding chemical elements, and then dissolve each raw material in a ball mill containing ethanol in turn; (2) placing the ball mill obtained in step (1) in a ball mill and ball milling at a speed of 260 r / min for 10 h; (3) placing the ball-milled solution in an oven and treating it at 160°C for 0.8 h to obtain a mixed powder; (4) Using a tablet press, the mixed powder of step (3) was placed under a pressure of 280 MPa for 150 seconds to obtain a dense tablet, and then calcined at 1200°C for 8 hours to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Material.

[0033] In this embodiment, a SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The cathode half-cell is prepared as follows: S1. Sm 0.2 Ce 0.8 O 1.9 (SDC) powder was used as electrolyte, and the electrolyte was obtained through tableting and calcination process; S2. SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The dense slices were manually ground for 30 min to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 The powder was dissolved in a ball mill containing ethanol and milled in a ball mill at 240 r / min for 22 h to obtain SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Cathode powder; S3. The SrCo obtained in S2 0.9 Ta0.1 O 3-δ F 0.05 The cathode powder and ethyl cellulose-terpineol (the mass fraction of ethyl cellulose is 6.5%) are fully ground and mixed in a ratio of 1:2 to prepare a cathode slurry; S4. The cathode slurry obtained in S3 is evenly coated on the surface of the electrolyte prepared in step S1 by a screen printer, and then calcined at 1200°C for 1h after drying to obtain a SrCo 0.9 Ta 0.1 O 3-δ F 0.05 Cathode half-cell.

[0034] The SrCo prepared by the methods described in Examples 4 and 5 above 0.9 Ta 0.1 O 3-δ F x The material has electrochemical properties that are substantially similar to those of Examples 1 to 3, and when x is adjusted within the range of x=0.05 to 0.2, the various parameters in the preparation method thereof can be adjusted accordingly with reference to Examples 4 and 5.

[0035] Comparative Example In this comparative example, a single perovskite-type MIEC oxide free of fluorine is provided, and the preparation method comprises the following steps: (1) According to the chemical formula SrCo 0.9 Ta 0.1 O 3-δ Weigh SrCO3, Co3O4, and Ta2O5 in the ratio of the stoichiometric number of the corresponding chemical elements, and then dissolve each raw material in a ball mill containing ethanol in turn; (2) placing the ball mill obtained in step (1) in a ball mill and ball milling at a speed of 240 r / min for 12 h; (3) The ball-milled solution was placed in an oven and treated at 150°C for 1 h to obtain a mixed powder; (4) Using a tablet press, the mixed powder of step (3) was placed under a pressure of 300 MPa for 120 s to obtain a dense tablet, and then calcined at 1100 °C for 10 h to obtain SrCo 0.9 Ta 0.1 O 3-δ Materials (referred to as SCT materials).

[0036] In this comparative example, a SrCo 0.9 Ta 0.1 O 3-δ The cathode half-cell, the preparation method comprises the following steps: S1. Sm 0.2 Ce 0.8 O1.9 (SDC) powder was used as electrolyte, and the electrolyte was obtained through tableting and calcination process; S2. SrCo 0.9 Ta 0.1 O 3-δ The dense slices were manually ground for 30 min to obtain SrCo 0.9 Ta 0.1 O 3-δ The powder was dissolved in a ball mill containing ethanol and milled in a ball mill at 240 r / min for 24 h to obtain SrCo 0.9 Ta 0.1 O 3-δ Cathode powder; S3. The SrCo obtained in S2 0.9 Ta 0.1 O 3-δ The cathode powder and ethyl cellulose-terpineol are fully ground and mixed in a mass ratio of 1:1.5 to prepare a cathode slurry; S4. The cathode slurry obtained in S3 is evenly coated on the surface of the electrolyte prepared in step S1 by a screen printer, and after drying, it is calcined at 1000°C for 2 h to obtain a SrCo 0.9 Ta 0.1 O 3-δ Cathode half-cell.

[0037] Performance Testing Figure 1 The XRD diagrams of the cathode materials in Examples 1 to 3 and the comparative example show that the synthesized materials are all pure phases. Figure 1 (b) is Figure 1 In the enlarged view of the 33-degree main peak in (a), it can be seen that as the doping amount of fluorine (F) increases, the diffraction peak gradually moves to a higher angle, proving that the lattice constant gradually decreases with the increase in the doping amount, indicating that F is successfully incorporated into the material lattice. In addition, the main peak of the embodiment changes from a double peak in the comparative example to a single peak, indicating that the lattice symmetry of the embodiment is improved, which is beneficial to its catalytic activity.

[0038] Figure 2 The SEM images of the cathode materials of Examples 1 to 3 and the comparative example after being treated in a chromium-containing atmosphere at 700°C for 24 hours. It can be seen that after the comparative example SCT material was treated in a chromium-containing atmosphere, more secondary phase particles appeared on the surface. However, after the F-doped Examples 1 to 3 were treated under the same conditions, the secondary phase on the surface was significantly reduced, indicating that F doping can significantly improve the stability of the material in a chromium-containing atmosphere.

[0039] Figure 3The XRD diagrams of the cathode materials of Examples 1 to 3 and the comparative example after being treated in a chromium-containing atmosphere at 700°C for 24 hours are shown. It can be seen that the surface of the comparative example SCT after treatment shows a diffraction peak belonging to the SrCrO4 secondary phase, indicating that the secondary phase generated on its surface is SrCrO4. However, the same secondary phase diffraction peaks were not observed in Examples 1 to 3 after treatment, further confirming that the amount of secondary phase generated on their surfaces was low.

[0040] Figure 4 The AC impedance spectra of the half-cells based on the cathode materials of Examples 1 to 3 and the comparative example are tested in a chromium-containing atmosphere at 700°C for 22 hours. It can be seen that after 22 hours of testing, the polarization resistance of the half-cell based on the comparative example SCT cathode material increases from the initial 0.120 Ω cm to 2 Increased to 1.150 Ω cm 2 , indicating that the activity of the SCT cathode material is significantly reduced. After 22 hours of testing under the same conditions, the batteries based on the cathode materials of Examples 1 to 3 all showed less polarization resistance growth, increasing to 0.416 Ω cm 2 , 0.272 Ω cm 2 and 0.495 Ω cm 2 , confirming that F replacing O can effectively improve the chromium resistance of SCT cathode.

[0041] Table 1 Polarization resistance values ​​of half cells in Examples 1 to 3 and Comparative Examples The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fuel cell cathode material with improved chromium resistance, characterized in that: The composition of the cathode material is shown in the following formula: SrCo 0.9 Ta 0.1 O 3-δ F x , x = 0.05 ~ 0.2; its XRD diffraction pattern contains 2 θ The X-ray diffraction peaks are at 33.00±0.1, 40.64±0.1, 47.20±0.1, 58.60±0.1, 68.70±0.1, and 78.12±0.

1.

2. The method for preparing the fuel cell cathode material according to claim 1, characterized in that: The following steps are included: 0.9 Ta 0.1 O 3-δ F x SrCO3, Co3O4, Ta2O5, and SrF2 are weighed in the ratio of the corresponding chemical element stoichiometric numbers, ball-milled by wet grinding, and then dried. The dried powder is allowed to stand at a pressure of 280-320 MPa for 100-150 seconds to obtain a dense sheet; the dense sheet is calcined at 1000-1200°C for 8-12 hours to obtain SrCo 0.9 Ta 0.1 O 3-δ F x The material is obtained by tableting and calcining.

3. The method for preparing the cathode material according to claim 2, characterized in that: The ball milling process uses ethanol as a solvent, the ball milling speed is 220-260 r / min, and the time is 10-14 hours.

4. The method for preparing a cathode material according to claim 2, characterized in that: The drying temperature is 140-160° C., and the drying time is 0.8-1.5 h.

5. A half-cell, characterized in that: The half-cell comprises the cathode material according to claim 1, and further comprises a solid electrolyte, wherein the solid electrolyte is selected from one or a combination of LSGM, SDC, and GDC.

6. The method for preparing the half-cell according to claim 5, characterized in that: The method comprises the following steps: wet-milling the cathode material to obtain powder, mixing the powder with an organic binder to prepare cathode slurry, coating the cathode slurry evenly on the surface of a solid electrolyte, drying the mixture, and calcining the mixture to obtain the cathode slurry.

7. The method for preparing a half-cell according to claim 6, characterized in that: The ball milling uses ethanol as a solvent, the ball milling speed is 220-260 r / min, and the time is 22-26 hours.

8. The method for preparing a half-cell according to claim 6, characterized in that: The organic binder is an ethyl cellulose pinene alcohol binder, wherein the mass ratio of ethyl cellulose to pinene alcohol is 1:12-19, and the mass ratio of the cathode material powder to the organic binder is 1:1-2.

9. The method for preparing a half-cell according to claim 6, characterized in that: The coating is achieved by a screen printing machine, and the cathode slurry is calcined at 800-1200° C. for 1-3 hours after drying.

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