Method for the production of electrolyte ceramic membranes for solid oxide cells

Abstract

The application relates to a preparation method of an electrolyte ceramic film for a solid oxide battery, which adopts a dry sintering process without using an organic solvent, and the process steps and conditions are as follows: electrolyte powder is mixed with a fiberizable binder through high-speed shearing; the binder-electrolyte powder mixture is subjected to hot roller pressing treatment to a set thickness; the electrolyte green body is sealed in a roughening medium and then subjected to hot isostatic pressing treatment to obtain an electrolyte green body with surface roughness, which is then cut into a green body sheet with a required size; the electrolyte green body is stacked with primary sintering auxiliary materials, and then degassing and primary sintering are carried out to obtain a primary sintered electrolyte ceramic film; the primary sintered electrolyte ceramic film is stacked with secondary sintering auxiliary materials, and then secondary sintering is carried out to obtain a secondary sintered electrolyte ceramic film with good flatness, the green body preparation process is greatly simplified, the increase of the particle packing density of the green body powder reduces the sintering temperature, the green body surface roughening treatment is adopted, the effect of non-sticking of the green body during stacking and sintering is realized, and the production efficiency is further increased; the prepared electrolyte ceramic film has the advantages of high density, high fracture strength, high high-temperature ionic conductivity and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field, and particularly relates to a preparation method of an electrolyte ceramic film for a solid oxide cell. BACKGROUND

[0002] Solid oxide cells (SOCs) are solid ceramic devices with dual functions of solid oxide electrolysis cells (SOECs) and solid oxide fuel cells (SOFCs). SOECs store renewable solar and wind energy in hydrogen fuel; SOFCs convert the chemical energy of hydrogen, natural gas and other hydrocarbons into electricity. According to the support type, SOCs can be divided into four types: metal support type, cathode support type, electrolyte support type and anode support type. Among them, the electrolyte support type SOCs are widely concerned and researched due to their good thermal cycle resistance and oxidation-reduction resistance, and the electrolyte support mainly uses sintered ceramic films of yttria-stabilized zirconia (YSZ) and scandia-stabilized zirconia (ScSZ). The basic structure of the electrolyte support type SOCs is: cathode / electrolyte ceramic film / anode, wherein the electrolyte support type SOCs are generally obtained by sintering after printing the cathode and anode slurry on both sides of the prepared electrolyte ceramic film.

[0003] Most of the electrolyte support type SOCs in the industry use electrolyte ceramic films prepared by tape casting sintering method, such as the electrolyte ceramic films prepared by the tape casting sintering method disclosed in patents CN200510121311.4, CN202010544090.6 and CN202311347983.1, which all go through processes of tape casting slurry preparation, tape casting forming, green body drying and low-temperature glue removal, and use toxic organic solvents in the slurry preparation process, and have problems of long production cycle, low good product rate, complex process, environmental unfriendliness, and low powder particle packing density due to the use of a large amount of binders and plasticizers in the tape casting green body, which leads to the need for higher sintering temperature and increases energy consumption.

[0004] Therefore, it is of great significance to develop a high-efficiency and low-consumption preparation method of an electrolyte ceramic film for a solid oxide cell. SUMMARY

[0005] The present application relates to the technical field, and particularly relates to a preparation method of an electrolyte ceramic film for a solid oxide cell.

[0006] The task of the present application is accomplished by the following technical scheme:

[0007] The application relates to a preparation method of an electrolyte ceramic film for a solid oxide battery.

[0008] S1. mixing the electrolyte powder and the fiberizable binder in a mixing device to realize high-speed shearing mixing to realize fiberization of the binder and uniform mixing of the binder and the electrolyte powder to obtain a binder-electrolyte powder mixture;

[0009] S2. performing hot roller pressing treatment on the binder-electrolyte powder mixture to a set thickness to obtain an electrolyte green body;

[0010] S3. sealing the electrolyte green body in a roughening medium and then performing hot isostatic pressing treatment to obtain an electrolyte green body with a certain surface roughness, and then cutting the electrolyte green body into a green body sheet with a required size;

[0011] S4. stacking the electrolyte green body and primary sintering auxiliary materials to perform glue removal and primary sintering to obtain a primary sintered electrolyte ceramic film;

[0012] S5. stacking the primary sintered electrolyte ceramic film and secondary sintering auxiliary materials to perform secondary sintering to obtain a secondary sintered electrolyte ceramic film with good flatness.

[0013] Compared with the prior art, the application has the following advantages or effects:

[0014] (1) The dry sintering process provided by the application does not need to use organic solvents to configure the casting slurry, and does not need to use additives such as dispersants and plasticizers, so that the use amount of organic matter is reduced, the harm of toxic organic solvents to the environment and human bodies is avoided, the time consumption in the glue removal stage is reduced, the green body preparation process is greatly simplified, and the green body preparation time is shortened;

[0015] (2) Meanwhile, since the dry method is adopted, the powder-powder accumulation is more compact, the powder quality in the electrolyte green body is increased by 25-29%, the powder particle packing density in the green body is increased, the mass transfer temperature between the powder particles is reduced, and the sintering temperature is reduced, so that energy saving and consumption reduction are realized;

[0016] (3) In addition, the hot isostatic water pressure treatment on the electrolyte green body increases the surface roughness of the green body, so that the green body stacking and sintering are not bonded, and the sintering efficiency and space utilization rate are improved;

[0017] (4) In addition, the physical and chemical properties of the ceramic film are basically kept unchanged.

[0018] In summary, the application can simplify the process of the electrolyte ceramic film and improve the production efficiency.

[0019] The % in the present application is mass percent. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a process flow diagram of a preparation method of an electrolyte ceramic film for a solid oxide cell according to the present application.

[0021] Figure 2 It is a schematic diagram of a one-time sintering stacked structure of the present application.

[0022] Figure 3 It is a schematic diagram of a two-time sintering stacked structure of the present application.

[0023] Figure 4 It is a schematic diagram of a physical electrolyte ceramic film after shaping of the present application.

[0024] Figure 5 It is a schematic diagram of a cross-sectional SEM picture of the electrolyte ceramic film after shaping of the present application.

[0025] In the drawings, each of the identifiers represents:

[0026] 1. weight piece 2. sintering gasket 3. electrolyte green body stack 4. alumina support plate 10. weight plate 20. sintering gasket plate 30. one-time sintering electrolyte ceramic film stack The present application is further described in detail below in conjunction with the drawings. DETAILED DESCRIPTION

[0027] Reference Figures 1 to 5 The preparation method of an electrolyte ceramic film for a solid oxide cell uses a dry sintering process without using organic solvents, aiming at the problems of using toxic organic solvents, long sintering time, high sintering temperature, complicated process flow and low efficiency in the preparation of electrolyte ceramic films by tape casting sintering method. The specific process steps and conditions are as follows:

[0028] S1. The electrolyte powder and the fiberizable binder are placed in a mixing device for high-speed shearing mixing to form a binder fiberization and uniformly mix with the electrolyte powder to form a binder-electrolyte powder mixture;

[0029] S2. The binder-electrolyte powder mixture is subjected to hot roller pressing treatment to a set thickness to obtain an electrolyte green body;

[0030] S3. The electrolyte green body is sealed in a roughening medium and subjected to hot isostatic pressing treatment to obtain an electrolyte green body with a certain surface roughness, and then cut into a green body piece of the required size;

[0031] S4. The electrolyte green body is stacked with a one-time sintering auxiliary material, and then subjected to degassing and one-time sintering to obtain a one-time sintering electrolyte ceramic film;

[0032] S5. The primary sintered electrolyte ceramic film is stacked with the secondary sintering auxiliary material, and then secondary sintering is performed to obtain a secondary sintered electrolyte ceramic film with good flatness.

[0033] The specific process steps and conditions of the present application can be further

[0034] The electrolyte powder is (Y2O3) 0.08 (ZrO2) 0.92 (8YSZ), (Sc2O3) 0.10 (CeO2) 0.01 (ZrO2) 0.89 (ScSZ), Ce 1-x Gd x O 2-x / 2 (GDC), Ce 1-x Sm x O 2-x / 2 (SDC), La 1-x Sr x Ga 1-y Mg y O 3-δ (LSGM) and BaCe 1-x- y Zr x M y O 3-δ at least one of (M = In, Y, Gd, Sm).

[0035] The fiberizable binder is at least one of polytetrafluoroethylene, polyimide, polyvinylidene fluoride, styrene butadiene rubber and carboxymethyl cellulose.

[0036] The content of the fiberizable binder in step S1 is 0.1-10%, and the electrolyte powder mixture is 90-99.9%.

[0037] The mixing device of the binder and the electrolyte in step S1 is at least one of an air flow crusher, a ball mill, a crusher, a screw extruder and an open mill.

[0038] The hot roller treatment in step S2 is multiple hot roller treatments using an electric counter roller machine, and the temperature of the hot roller treatment is 30-100℃.

[0039] The thickness of the electrolyte green body in step S2 is 30-250μm.

[0040] The roughening medium in step S3 is at least one of emulsified glass, sulfuric acid paper, stainless steel plate and frosted acrylic plate, and the surface roughness of the roughening medium is 0.5-1.2μm.

[0041] The step S3 isostatic pressure is hot isostatic pressure or die pressing, the hot isostatic pressure treatment pressure is 30-100 MPa, the temperature is 30-100 DEG C, and the pressure maintaining time is 20-100 min.

[0042] The step S4 electrolyte green body and the first sintering auxiliary material stacking structure include a pressing weight piece 1, a sintering gasket 2, an electrolyte green body stacking 3, and an alumina support plate 4.

[0043] The step S4 pressing weight piece 1 is at least one of a porous alumina plate, a porous zirconia plate, and a porous magnesium oxide plate, and the weight is 0.3-0.9 Kg.

[0044] The step S4 sintering gasket 2 is at least one of (Y2O3) 0.03 (ZrO2) 0.97 (3YSZ) green body, cerium oxide green body, and lanthanum gallate green body.

[0045] The step S4 electrolyte green body stacking 3 contains 1-20 pieces of electrolyte green bodies.

[0046] The step S4 electrolyte green body has a degassing temperature of 250-400 DEG C, a degassing temperature holding time of 1-5 h, a first sintering temperature of 1000-1500 DEG C, and a first sintering temperature holding time of 1-8 h; the temperature rising rate from room temperature to the degassing temperature is 0.1-1 DEG C / min, and the temperature rising rate from the degassing temperature to the first sintering temperature is 1-10 DEG C / min.

[0047] The step S5 first sintering electrolyte ceramic film and the second sintering auxiliary material stacking structure include a pressing weight plate 10, a sintering gasket 20, a first sintering electrolyte ceramic film stacking 30, and an alumina support plate 4.

[0048] The step S5 pressing weight plate 10 is at least one of a silicon carbide plate, a zirconia plate, a magnesium oxide plate, and an alumina plate, and the weight is 1.0-5.0 Kg.

[0049] The step S5 sintering gasket 20 is a ceramic piece obtained by sintering the sintering gasket 2 in the step S4, and is at least one of a 3YSZ ceramic piece, a cerium oxide ceramic piece, and a lanthanum gallate ceramic piece.

[0050] The step S5 first sintering electrolyte ceramic film stacking 30 contains 10-30 pieces of first sintering electrolyte ceramic films.

[0051] The step S5 second sintering temperature is 10-30 DEG C higher than the first sintering temperature; the second sintering temperature holding time is 1-5 h, and the temperature rising rate is 1-10 DEG C / min.

[0052] In the following examples, the ScSZ powder used was purchased from Jiangxi Sai Ceramics, with a D50 of 0.5 pm and a specific surface area of 9-12 m2 / g; the 3YSZ powder and 8YSZ powder used were purchased from Shenzhen Kejing, with a D50 of 0.5±0.2 pm and a specific surface area of 12±2 m2 / g; the PTFE powder used was purchased from Shenzhen Kejing, with a D50 of 500 pm. 2 / g; the 3YSZ powder and 8YSZ powder used were purchased from Shenzhen Kejing, with a D50 of 0.5±0.2 pm and a specific surface area of 12±2 m 2 / g; the PTFE powder used was purchased from Shenzhen Kejing, with a D50 of 500 pm.

[0053] Example 1

[0054] Preparation of ScSZ electrolyte ceramic membrane

[0055] S1: ScSZ powder and PTFE powder were weighed according to a mass ratio of 95:5 and placed in a crusher for high-speed shearing mixing, so that the PTFE powder was fiberized and fully mixed with the ScSZ powder to obtain a fiberized PTFE-ScSZ mixture; the rotation speed of the crusher was 3000 rpm and the mixing time was 20 min.

[0056] S2: The fiberized PTFE-ScSZ mixture was placed in an electric counter-roller machine for multiple hot roller pressing treatments, with the roller gap gradually reduced, so that the thickness of the electrolyte green body was finally maintained at 65 pm; the temperature of the hot roller pressing treatment was 70 °C.

[0057] S3: The ScSZ electrolyte green body was sandwiched between two sheets of sulfuric acid paper and placed in a PET bag for vacuum sealing, and then placed in a hydrostatic press for hydrostatic pressing to obtain a surface-roughened ScSZ electrolyte green body; the hydrostatic pressure was 80 MPa and the pressure holding time was 30 min.

[0058] S4: The surface-roughened ScSZ electrolyte green body and the first sintering auxiliary material were stacked according to the structure shown in Figure 2 , from bottom to top in order: an alumina support plate, a 3YSZ green body, 10 pieces of surface-roughened ScSZ electrolyte green body, a 3YSZ green body, and a 0.6 mm porous alumina ceramic sheet, followed by glue removal and sintering in a muffle furnace; the glue removal temperature was 300 °C, the glue removal time was 2 h, the temperature rising rate from room temperature to the glue removal temperature was 0.5 °C / min, the first sintering temperature was 1220 °C, the holding time was 2 h, and the temperature rising rate from the glue removal temperature to the sintering temperature was 5 °C / min; after cooling, a ScSZ first sintered ceramic membrane was obtained. The 3YSZ green body was prepared by the steps of S1 and S2, except that 3YSZ powder was used instead of 8YSZ powder.

[0059] S5: The first sintered ScSZ ceramic membrane and the second sintering auxiliary material were stacked according to the structure shown in Figure 3The structure stack shown from bottom to top is an alumina support plate, a 3YSZ ceramic sheet, 20 pieces of a primary sintered ScSZ ceramic film, a 3YSZ ceramic sheet, and a 0.7Kg silicon carbide weight plate, which are then placed in a muffle furnace; the 3YSZ ceramic sheet is obtained by sintering in the S3 step, the secondary sintering temperature is 1240℃, the holding time is 2h, and the heating rate is 5℃ / min; and a ScSZ ceramic film is obtained after cooling as shown in Figure 4 The ScSZ ceramic film shown.

[0060] Example 2

[0061] Preparation of a ScSZ electrolyte ceramic film

[0062] The difference from Example 1 is that the mass ratio of ScSZ powder to PTFE powder is 97:3, and the thickness of the ScSZ electrolyte green body is 115μm.

[0063] Example 3

[0064] Preparation of an 8YSZ electrolyte ceramic film

[0065] The difference from Example 1 is that the electrolyte powder is 8YSZ powder, the primary sintering temperature of the 8YSZ green body is 1320℃, and the secondary sintering temperature is 1340℃.

[0066] Example 4

[0067] Preparation of an 8YSZ electrolyte ceramic film

[0068] The difference from Example 3 is that the mass ratio of 8YSZ powder to PTFE powder is 97:3, and the thickness of the ScSZ electrolyte green body is 115μm.

[0069] Comparative Example 1

[0070] Preparation of a ScSZ ceramic film by a traditional tape casting sintering method

[0071] S1: xylene, ethanol, fish oil, ScSZ powder, BBP, PAG, PVB, and cyclohexanone were weighed according to the mass ratio of 21:21:1.5:49:1.6:1.6:4.1:0.2; xylene, ethanol, fish oil, and ScSZ powder were first placed in a zirconia ball mill jar and ball milled at a speed of 800rpm for 24h, then BBP, PAG, PVB, and cyclohexanone were added and ball milled at a speed of 800rpm for 16h; the slurry was degassed using a degassing machine under negative pressure for 60min to obtain a casting slurry.

[0072] S2: the slurry obtained in S1 was coated onto a PET film using a wire bar coater, and the green body thickness was controlled at 65μm; the cast green body was dried at room temperature for 12h.

[0073] S3: Hydroisostatic pressure treatment was performed on the ScSZ green tape. Except that the green tape was dried at 120℃ for 120min before the hydroisostatic pressure, the rest of the steps were consistent with the S3 step in Example 1.

[0074] S4: The roughened ScSZ green tape was subjected to laminated sintering. Except that the debinding temperature was changed to 400℃, the debinding time was changed to 6h, and the first sintering temperature was changed to 1350℃, the rest of the steps were consistent with the S4 step in Example 1.

[0075] S5: The first sintered ScSZ ceramic membrane was subjected to high-temperature shaping. Except that the second sintering temperature was changed to 1370℃, the rest of the steps were consistent with the S5 step in Example 1.

[0076] Comparative Example 2

[0077] ScSZ ceramic membrane prepared by traditional tape casting and sintering

[0078] The difference from Comparative Example 1 is that the mass ratio of ScSZ powder to PTFE powder is 97:3, and the thickness of the ScSZ electrolyte green tape is 115μm.

[0079] Comparative Example 3

[0080] 8YSZ ceramic membrane prepared by traditional tape casting and sintering

[0081] The difference from Comparative Example 1 is that the electrolyte powder is 8YSZ powder, the first sintering temperature of the 8YSZ green tape is 1430℃, and the second sintering temperature is 1450℃.

[0082] Comparative Example 4

[0083] 8YSZ ceramic membrane prepared by traditional tape casting and sintering

[0084] The difference from Comparative Example 3 is that the mass ratio of 8YSZ powder to PTFE powder is 97:3, and the thickness of the 8YSZ electrolyte green tape is 115μm.

[0085] Performance characterization of the examples and comparative examples:

[0086] The thickness was measured using a micrometer; the relative density was measured by the Archimedes drainage method; the fracture strength of the electrolyte ceramic membrane was measured using a universal testing machine; and the ionic conductivity of the electrolyte ceramic membrane at 800℃ was measured using an electrochemical workstation combined with a high-temperature tube furnace.

[0087] The surface and cross-section of the electrolyte ceramic membrane were characterized by SEM, and the cross-section SEM of the electrolyte ceramic membrane of Example 1 is shown in Figure 5 .

[0088] The characterization results of the electrolyte ceramic membranes of Examples 1-4 and Comparative Examples 1-4 are summarized in Table 1.

[0089] Table 1 Characterization data of electrolyte ceramic membranes

[0090]

[0091] Results and evaluation:

[0092] like Figure 4 As shown, the ScSZ ceramic film prepared in Example 1 has good flatness and no obvious surface defects. Figure 5 As shown in the cross-sectional SEM image of the ScSZ ceramic membrane prepared in Example 1, the ceramic exhibits transgranular fracture, with tight intergranular contact and no obvious pores, indicating a dense structure. As shown in Table 1, the relative density, tensile strength, and ionic conductivity at 800℃ of the electrolyte ceramic membrane prepared in this example are not significantly different from those of the comparative sample. This demonstrates that the dry sintering process provided by this invention is suitable for the preparation of electrolyte ceramic membranes, and can obtain dense electrolyte ceramic membranes with high ionic conductivity and high tensile strength.

[0093] As described above, the present invention can be well implemented. The above embodiments are only the best implementations of the present invention, but the implementation of the present invention is not limited to the above embodiments. Other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are all included within the protection scope of the present invention.

Claims

1. A method for the production of electrolyte ceramic membranes for solid oxide cells, characterized in that The dry sintering process without using organic solvents is adopted, and the specific process steps and conditions are as follows: S1. The electrolyte powder and the fiberizable binder are placed in a mixing device for high-speed shearing mixing to form a binder fiberization and uniform mixing with the electrolyte powder to form a binder-electrolyte powder mixture; S2. The binder-electrolyte powder mixture is subjected to hot roller pressing treatment to a set thickness to obtain an electrolyte green body; S3. The electrolyte green body is sealed in a roughening medium and subjected to hot isostatic pressing treatment to obtain an electrolyte green body with a certain surface roughness, and then cut into a green body sheet of the required size; S4. The electrolyte green body is stacked with the first sintering auxiliary material, and then degassing and first sintering are performed to obtain a first sintered electrolyte ceramic membrane; S5. The first sintered electrolyte ceramic membrane is stacked with the second sintering auxiliary material, and then second sintering is performed to obtain a second sintered electrolyte ceramic membrane with good flatness.

2. The method of claim 1 wherein The electrolyte powder is at least one of (Y2O3) 0.08 (ZrO2) 0.92 , (Sc2O3) 0.10 (CeO2) 0.01 (ZrO2) 0.89 , Ce 1-x Gd x O 2-x / 2 , Ce 1-x Sm x O 2-x / 2 , La 1-x Sr x Ga 1-y Mg y O 3-δ and BaCe 1-x- y Zr x M y O3, wherein M is one of In, Y, Gd, Sm.

3. The method of claim 1 wherein The fiberizable binder is at least one of polytetrafluoroethylene, polyimide, polyvinylidene fluoride, butadiene rubber, and carboxymethyl cellulose.

4. The method of claim 1 wherein In step S1, the content of the fiberizable binder is 0.1-10%, and the electrolyte powder mixing is 90-99.9%.

5. The production method according to claim 1 or 4, characterized by In step S1, the fiberizable binder and electrolyte mixing device is at least one of an air flow crusher, a ball mill, a pulverizer, a screw extruder, and an open mill.

6. The method of claim 1 wherein In step S2, the hot roller pressing treatment is performed using an electric roller mill for multiple times, and the temperature of the hot roller pressing treatment is 30-100℃.

7. The method of claim 1 or 6, wherein In step S2, the set thickness of the electrolyte green body is 30-250μm.

8. The method of claim 1 wherein In step S3, the roughening medium is at least one of emulsified glass, sulfuric acid paper, stainless steel plate, and frosted acrylic plate, and the surface roughness of the roughening medium is 0.5-1.2μm.

9. The method of claim 1 or 8, wherein In step S3, the hot isostatic pressing method is hot isostatic water pressure or die pressing, the hot isostatic pressing pressure is 30-100MPa, the temperature is 30-100℃, and the pressure holding time is 20-100min.

10. The method of claim 1 wherein In step S4, the stacking structure of the electrolyte green body and the first sintering auxiliary material includes a weight plate, a sintering gasket one, an electrolyte green body stacking, and an alumina support plate.

11. The method of claim 10, wherein In step S4, the weight plate is at least one of a porous alumina plate, a porous zirconia plate, and a porous magnesium oxide plate, and the weight is 0.3-0.9Kg.

12. The method of claim 10, wherein The sintering pad in the step S4 is (Y2O3) 0.03 (ZrO2) 0.97 at least one of a green body, a ceria green body, a lanthanum gallate green body.

13. The method of claim 10 wherein In step S4, the electrolyte green body stacking contains 1-20 electrolyte green bodies.

14. The method of claim 1 or 10 or 11 or 12 or 13, wherein In step S4, the degassing temperature of the electrolyte green body is 250-400℃, the degassing temperature holding time is 1-5h, the first sintering temperature is 1000-1500℃, the first sintering temperature holding time is 1-8h, the heating rate from room temperature to the degassing temperature is 0.1-1℃ / min, and the heating rate from the degassing temperature to the first sintering temperature is 1-10℃ / min.

15. The method of claim 1 wherein In step S5, the stacking structure of the first sintered electrolyte ceramic membrane and the second sintering auxiliary material includes a weight plate, a sintering gasket two, a first sintered electrolyte ceramic membrane stacking, and an alumina support plate.

16. The method of claim 15, wherein In step S5, the weight plate is at least one of a silicon carbide plate, a zirconia plate, a magnesium oxide plate, and an alumina plate, and the weight is 1.0-5.0Kg.

17. The method of claim 15 wherein The sintered gasket two in the step S5 is a ceramic sheet obtained after the sintered gasket one in the step S4 is sintered once, which is (Y2O3) 0.03 (ZrO2) 0.97 at least one of a ceramic sheet, a ceria ceramic sheet, and a lanthanum gallate ceramic sheet.

18. The method of claim 15 wherein The number of the once sintered electrolyte ceramic membrane stacks in the step S5 is 10-30.

19. The method of claim 1 or 15 or 16 or 17 or 18, wherein The temperature of the secondary sintering in the step S5 is 10-30℃ higher than that of the once sintering; the holding time of the secondary sintering temperature is 1-5h, and the heating rate is 1-10℃ / min.

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