A method for simply preparing LaGaO3-based electrolyte thin sheets
By combining solid-state reaction with casting, La1-xSrxGa1-yMgyO3 electrolyte sheets were directly prepared, solving the problems of complex processes and high costs in existing technologies. This method achieves efficient and low-cost preparation of electrolyte sheets and has good industrialization potential.
Patent Information
- Application Number
- CN202311186926.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-14
- Publication Date
- 2026-01-02
- Estimated Expiration
- 2043-09-14
AI Technical Summary
Existing technologies require multiple heat treatments in the preparation of La1-xSrxGa1-yMgyO3 electrolytes, resulting in complex processes and high costs, making it difficult to achieve efficient and low-cost preparation of electrolyte sheets.
A combination of solid-state reaction and casting method was adopted. The raw material powder and organic additives were directly mixed and ball-milled into a slurry, which was then cast, dried and cut. Finally, high-temperature sintering was carried out to obtain pure phase La1-xSrxGa1-yMgyO3 electrolyte sheets.
The preparation process was simplified, the cost was reduced, and high-performance dense electrolyte sheets were obtained, which have good prospects for industrialization.
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Figure CN117229057B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of fuel cells, in particular to a method for simply preparing LaGaO3-based electrolyte sheet. BACKGROUND
[0002] Solid oxide fuel cell (SOFC) is a clean and efficient energy conversion device, which has the advantages of wide fuel application, low cost, easy modular design, wide application field, and all-solid device, and has become the focus of social attention. The electrolyte is one of the key materials of SOFC, which functions to conduct oxygen ions between the cathode and the anode, and separate the fuel and the oxidant. The commonly used electrolyte material is yttria-stabilized zirconia (YSZ), but its oxygen ion conductivity is relatively low, and it needs to be operated at a high temperature. In order to reduce the operating temperature of the cell, the thickness of the electrolyte is generally reduced or high-conductivity materials are used.
[0003] Strontium and magnesium doped LaGaO3-based electrolyte La 1-x Sr x Ga 1-y Mg y O3 has excellent oxygen ion conductivity, and its conductivity is higher than that of YSZ and close to that of scandia-stabilized zirconia, so it is often used in some intermediate-temperature SOFCs. At present, La 1- x Sr x Ga 1-y Mg y O3 powder is usually prepared by a solid phase reaction method, which is first pre-sintered at 1000-1200 ℃, then refined by ball milling, and then high-temperature calcined, and finally the La 1-x Sr x Ga 1-y Mg y O3 electrolyte powder obtained by high-temperature calcination is used as a forming raw material to prepare an electrolyte sheet. It can be seen that the existing solid phase reaction method needs to go through multiple heat treatments to avoid the generation of impurities in the process of preparing La 1-x Sr x Ga 1-y Mg y O3 electrolyte.
[0004] The tape casting method is a method for efficiently and large-scale preparing thin electrolytes with certain shape, size and performance (density, strength, microstructure, etc.), which is widely used in the preparation of La 1-x Sr x Ga 1-y Mg y O3 electrolyte. It mainly uses phase-formed La 1-x Sr x Ga 1-y O3 powder as a raw material, and then a green body is prepared by mixing the LaMg y O3 powder as raw material to realize the forming of electrolyte. SUMMARY
[0005] The present application aims to provide a simple method for preparing LaGaO3-based electrolyte sheet, which directly prepares pure-phase La 1-x Sr x Ga 1-y Mg y O3 electrolyte sheet by combining solid-phase reaction with flow casting, so as to effectively reduce the preparation process and cost of electrolyte.
[0006] To achieve the above object, the present application adopts the following technical solutions:
[0007] A simple method for preparing LaGaO3-based electrolyte sheet, comprising the following steps:
[0008] (1) preparing La2O3, SrCO3, Ga2O3 and MgO raw material powders according to the stoichiometric ratio of La 1-x Sr x Ga 1-y Mg y O3 (x=0-0.3, y=0-0.3);
[0009] (2) ball-milling and uniformly mixing the prepared raw material powders with organic additives to obtain slurry;
[0010] (3) using flow casting method to prepare La 1-x Sr x Ga 1-y Mg y O3 green body from the obtained slurry, and cutting it into the required size after room temperature drying;
[0011] (4) obtaining dense La 1-x Sr x Ga 1- y Mg y O3 electrolyte sheet with pure-phase structure by degreasing and high-temperature sintering of the cut green body.
[0012] Further, the components in the organic additives in step (2) and the percentage of the total mass of the used materials are as follows: solvent 40-60 %, dispersant 1-3 %, plasticizer 4-8 %, and binder 3-10 %.
[0013] Further, the solvent is mixed by anhydrous ethanol and butanone in a mass ratio of 3:2.
[0014] Further, the dispersant is triethanolamine.
[0015] Further, the plasticizer is formed by mixing polyethylene glycol and diethyl phthalate in a mass ratio of 1:1.
[0016] Further, the binder is polyvinyl butyral.
[0017] Further, the ball milling time in step (2) is 4-20 h, and the rotating speed is 100-400 r·min -1 .
[0018] Further, the casting speed in step (3) is 20-50 mm·s -1 , and the doctor blade height is 100-2000 μm.
[0019] Further, the room temperature drying time in step (3) is 4-30 h.
[0020] Further, the temperature for the glue removal in step (4) is 400-600 ℃, and the time is 1-5 h.
[0021] Further, the temperature for the high-temperature sintering in step (4) is 1400-1550 ℃, and the time is 3-20 h.
[0022] The present application has the following advantages:
[0023] The present application mixes raw material powder with organic additives directly to obtain slurry by ball milling, and then obtains green body by casting and drying, and finally obtains dense La 1-x Sr x Ga 1-y Mg y O3 (x=0-0.3, y=0-0.3) electrolyte sheet by glue removal and one-step high-temperature sintering. Compared with the existing process, the present application does not need to use pure phase La 1-x Sr x Ga 1-y Mg y O3 powder as raw material, avoids the complex operation of two-step sintering in traditional solid phase reaction, shortens the preparation process of La 1-x Sr x Ga 1-y Mg y O3 electrolyte sheet, and provides a new idea for the development of low-cost and high-performance La 1-x Sr x Ga 1-y Mg y O3 electrolyte sheet, and has good industrialization prospect. BRIEF DESCRIPTION OF DRAWINGS
[0024] Figure 1 La1-x Sr x Ga 1-y Mg y Flow chart of La
[0025] Figure 2 La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 XRD pattern of La
[0026] Figure 3 La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 Bending strength test curve of La
[0027] Figure 4 La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 Surface (a) and cross-section (b) morphology of La
[0028] Figure 5 La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 Elemental distribution map of La
[0029] Figure 6 La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 Impedance spectrogram of La DETAILED DESCRIPTION
[0030] A method for simply preparing LaGaO3-based electrolyte flake, such as Figure 1 , comprises the following steps:
[0031] (1) according to La 1-x Sr x Ga 1-y Mg yThe stoichiometric ratio of O3 (x=0-0.3, y=0-0.3) is prepared by La2O3, SrCO3, Ga2O3, MgO raw material powder;
[0032] (2) The prepared raw material powder is mixed with a solvent (a mixture of anhydrous ethanol and butanone in a mass ratio of 3:2), a dispersant triethanolamine, a plasticizer (a mixture of polyethylene glycol and diethyl phthalate in a mass ratio of 1:1), and a binder polyvinyl butyral, and is mixed at 100-400 r·min -1 for 4-20 h to make it uniform, to obtain a slurry;
[0033] (3) The speed of the casting is set to 20-50 mm·s -1 , and the scraper height is 100-2000 μm, the obtained slurry is used to make La 1-x Sr x Ga 1-y Mg y O3 green body by the casting method, and is cut into the required size after drying at room temperature for 4-30 h;
[0034] (4) The cut green body is degassed at 400-600 ℃ for 1-5 h, and is high-temperature sintered at 1400-1550 ℃ for 3-20 h to obtain a dense La 1-x Sr x Ga 1-y Mg y O3 electrolyte sheet with a pure phase structure.
[0035] In step (2), the percentage of each component in the total mass of the material is 40-60 % of the solvent, 1-3 % of the dispersant, 4-8 % of the plasticizer, and 3-10 % of the binder, and the balance is the raw material powder.
[0036] In order to make the content of the application more convenient to understand, the technical solutions of the application will be further described below in combination with specific embodiments, but the application is not limited thereto.
[0037] Example 1:
[0038] (1) 25.58 g of La2O3, 2.58 g of SrCO3, 13.08 g of Ga2O3, 1.41 g of MgO, 1 g of triethanolamine, 2.5 g of polyethylene glycol, 2.5 g of diethyl phthalate, 8 g of polyvinyl butyral, and 30 g of anhydrous ethanol, 20 g of butanone are weighed, and are ball milled at 300 r·min -1 for 8 h to obtain an electrolyte slurry;
[0039] (2) The electrolyte slurry was placed in a vacuum degassing machine and degassed under vacuum at 0.9 MPa for 35 min. After vacuum degassing, the scraper height was set to 1200 μm and the casting speed was set to 35 mm·s. -1 Perform the casting process; after casting, dry at room temperature for 24 h to obtain the cast green body;
[0040] (3) The obtained green body is cut and sampled using a φ20 circular die; then the sample is placed in a sintering furnace and debinded at 500 ℃ for 5 h; then the debinded sample is sintered at 1450 ℃ for 15 h to obtain La. 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O3 (LSGM) Electrolyte Tablets.
[0041] Example 2:
[0042] (1) Weigh 22.74 g La2O3, 5.15 g SrCO3, 13.08 g Ga2O3, 1.41 g MgO, 1 g triethanolamine, 2.1 g polyethylene glycol, 2.1 g diethyl phthalate, 9 g polyvinyl butyral, 40 g anhydrous ethanol, and 26 g butanone, and salicylate at 300 r·min -1 Ball milling for 8 hours yielded an electrolyte slurry;
[0043] (2) The electrolyte slurry was placed in a vacuum degassing machine and degassed under vacuum at 0.9 MPa for 35 min. After vacuum degassing, the scraper height was set to 1200 μm and the casting speed was set to 35 mm·s. -1 Perform the casting process; after casting, dry at room temperature for 24 h to obtain the cast green body;
[0044] (3) The obtained green body is cut and sampled using a φ20 circular die; then the sample is placed in a sintering furnace and debinded at 500 ℃ for 5 h; then the debinded sample is sintered at 1450 ℃ for 15 h to obtain La. 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O3 (LSGM) Electrolyte Tablets.
[0045] Comparative example:
[0046] (1) Weigh 22.74 g La2O3, 5.15 g SrCO3, 13.08 g Ga2O3 and 1.41 g MgO, add anhydrous ethanol as solvent, and reflux at 300 r·min -1After mixing uniformly by ball milling for 10 h, the initial powder was obtained by drying at 80℃ for 10 h. The initial powder was pressed into a mold and pre-sintered at 1200℃ for 10 h. Then the pre-sintered sample was crushed and sintered at 300 r·min -1 for 10 h. The pre-sintered powder was pressed into a mold and sintered at 1450℃ for 10 h. Then the sintered sample was crushed and sintered at 300 r·min -1 for 10 h. The final La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O3 (LSGM) powder was obtained by ball milling for 10 h.
[0047] (2) 41.4 g of LSGM powder, 1 g of triethanolamine, 2.5 g of polyethylene glycol, 2.5 g of diethyl phthalate, 8 g of polyvinyl butyral, and 30 g of anhydrous ethanol, 20 g of methyl ethyl ketone were weighed, and the mixture was ball milled at 300 r·min -1 for 8 h to obtain an electrolyte slurry;
[0048] (3) The electrolyte slurry was placed in a vacuum defoaming machine and vacuum defoamed at 0.9 MPa for 35 min. After vacuum defoaming, the scraper height was set to 1200 μm and the casting speed was 35 mm·s -1 for casting operation. After casting, the green body was dried at room temperature for 24 h to obtain a cast green body;
[0049] (4) The obtained green body was cut and sampled using a φ20 circular knife mold. Then the sample was placed in a sintering furnace and degassed at 500℃ for 5 h. Then the degassed sample was sintered at 1450℃ for 15 h to obtain an LSGM electrolyte sheet.
[0050] Performance characterization:
[0051] Figure 2 XRD pattern of the LSGM electrolyte sheet prepared in Example 1. As can be seen from the figure, the crystal structure of the LSGM is cubic perovskite phase, and no impurity phase is generated, which indicates that this method can obtain pure phase LSGM electrolyte.
[0052] Figure 3 Bending strength test curve of the LSGM electrolyte prepared in Example 1. After fitting calculation, the bending strength of the LSGM electrolyte is 132 MPa.
[0053] Figure 4The surface (a) and cross-section (b) morphology of the LSGM electrolyte prepared in Example 1. As can be seen from the figure, the thickness of the obtained electrolyte is about 140 μm, and the surface and cross-section of the electrolyte are dense and substantially free of holes, indicating that the present application can prepare sufficiently dense electrolyte sheets.
[0054] Figure 5 The element distribution of the LSGM electrolyte prepared in Example 1. As can be seen from the figure, the distribution of the constituent elements of the LSGM electrolyte is uniform, indicating that the solid phase reaction is very thorough.
[0055] Figure 6 The AC impedance spectrum of the electrolyte sheets prepared in Example 1 and the comparative example at 800 ℃. As can be seen from the figure, the ohmic resistance of the electrolyte sheets prepared in Example 1 and the comparative example at 800 ℃ is 0.18 Ω·cm 2 and 0.19 Ω·cm 2 , respectively, and the ion conductivity obtained by calculation is 0.105 S·cm ‒1 and 0.103 S·cm ‒1 , respectively. It can be seen that the conductivity of the LSGM electrolyte sheet prepared by the present application is not much different from that of the electrolyte sheet prepared by the existing process, indicating the feasibility of the present application.
[0056] The above description is only the preferred embodiment of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be included in the scope of the present application.
Claims
1. A simple method for preparing LaGaO3-based electrolyte thin films, characterized in that, Includes the following steps: (1) According to La 1-x Sr x Ga 1-y Mg y Prepare raw material powders of La2O3, SrCO3, Ga2O3, and MgO with stoichiometric ratios of O3, where x = 0-0.3 and y = 0-0.3; (2) The prepared raw material powder and organic additives are ball-milled and mixed to obtain a slurry; (3) The obtained slurry is used to make La using the casting method. 1-x Sr x Ga 1-y Mg y O3 green body, after being dried at room temperature, is cut into the required size; (4) The cut green body is debonded and sintered at high temperature to obtain a dense La with a pure phase structure. 1-x Sr x Ga 1-y Mg y O3 electrolyte sheets; The components of the organic additive mentioned in step (2) and their percentages in the total mass of the materials used are: solvent 40-60%, dispersant 1-3%, plasticizer 4-8%, and binder 3-10%; The solvent is composed of anhydrous ethanol and butanone in a mass ratio of 3:
2. The dispersant is triethanolamine; The plasticizer is a mixture of polyethylene glycol and diethyl phthalate in a mass ratio of 1:
1. The adhesive is polyvinyl butyral; The ball milling speed in step (2) is 100-400 r·min. -1 The time is 4-20 hours; The high-temperature sintering temperature in step (4) is 1400-1550 ℃ and the time is 3-20 h.
2. The method for easily preparing LaGaO3-based electrolyte sheets according to claim 1, characterized in that: The casting speed in step (3) is 20-50 mm·s. -1 The scraper height is 100-2000 μm.
3. The method for easily preparing LaGaO3-based electrolyte sheets according to claim 1, characterized in that: The temperature for degreasing in step (4) is 400-600 ℃ and the time is 1-5 h.