A gadolinium oxide-doped cerium oxide film and its preparation method and application

Abstract

This application discloses a gadolinium-doped cerium oxide thin film, its preparation method, and its application, relating to the field of thin film materials technology. This application prepares a gadolinium-doped cerium oxide layer using a DC magnetron sputtering process at a specific growth temperature. After the DC magnetron sputtering process, a first annealing and a second annealing are performed in a specific gas atmosphere. This effectively improves the adhesion of the gadolinium-doped cerium oxide layer to the substrate and enhances its stability, making the resulting thin film suitable for use as an electrolyte in solid fuel cells.

Description

Technical Field

[0001] This application relates to the field of thin film materials technology, and specifically to a gadolinium oxide-doped cerium oxide thin film, its preparation method, and its application. Background Technology

[0002] Solid oxide fuel cells (SOFCs) exhibit excellent energy conversion efficiency, with intermediate-temperature (IT-SOFCs) offering lower operating temperatures and better safety. For IT-SOFCs with cobalt-containing perovskite cathodes (such as LSCF (lanthanum-strontium-cobalt-iron) or BSCF (strontium-barium iron-ferrocobalt)), the properties of the doped cerium oxide separator, used to prevent interfacial reactions between the cathode and the yttrium-stabilized zirconium oxide (YSZ) electrolyte, are crucial. Doped cerium oxide separators are typically prepared using a combination of wet coating and sintering. However, cerium oxide readily reacts with YSZ, and the porous structure of the cerium oxide separator contributes to poor interfacial performance. These factors indicate that conventional processes cannot produce ideal cerium oxide separators.

[0003] The role of electrolyte materials is to transfer oxygen ions between the cathode and anode and to effectively isolate fuel and oxidant, which requires them to have good adhesion and stability on the substrate. Therefore, it is crucial to fabricate a gadolinium oxide-doped cerium oxide (GDC) layer on the substrate that meets these requirements. Summary of the Invention

[0004] Based on the deficiencies of the existing technology, the purpose of this application is to provide a gadolinium oxide-doped cerium oxide thin film, its preparation method and application, so as to effectively improve the adhesion of the gadolinium oxide-doped cerium oxide layer on the substrate and make it have good stability.

[0005] To achieve the above objectives, this application provides a method for preparing gadolinium oxide-doped cerium oxide thin films, comprising the following steps:

[0006] A gadolinium oxide-doped cerium oxide layer is prepared on at least one side of a substrate using a DC magnetron sputtering process, wherein the growth temperature is 80-200℃;

[0007] A first annealing is performed in a first gas atmosphere, followed by a second annealing in a second gas atmosphere to obtain a gadolinium-doped cerium oxide film. The first gas includes at least one of nitrogen, an inert gas, and oxygen, and the second gas is air.

[0008] The above-mentioned method for preparing gadolinium oxide-doped cerium oxide thin films involves controlling DC magnetron sputtering at a specific temperature, followed by a first and second annealing in a specific gas atmosphere after DC magnetron sputtering. This effectively improves the adhesion of the gadolinium oxide-doped cerium oxide layer to the substrate and enhances its stability, making it suitable for use as a solid fuel cell electrolyte, especially for use as a medium-temperature solid fuel cell electrolyte.

[0009] In some embodiments, the oxygen partial pressure in the first gas is 10%-30% to improve the film density, adhesion, and stability.

[0010] In some embodiments, the first annealing meets the following conditions: temperature 250-650°C, time 2-5 hours, and pressure 0.4-0.8 Pa, so as to improve the film density, adhesion, and stability.

[0011] In some embodiments, the second annealing meets the following requirements: temperature 350-650℃, time 2-3h, and pressure 1×10⁻⁶. 4 -1×10 5 Pa, to make the film denser, with better adhesion and stability.

[0012] In some embodiments, the DC magnetron sputtering process satisfies:

[0013] The distance between the center of the target and the center of the substrate is 6-10 cm;

[0014] The partial pressure of oxygen is 10%-30%;

[0015] The sputtering power density of the target is 2.5-5.5 W / cm³. 2 ;

[0016] The sputtering pressure is 0.4-0.8 Pa;

[0017] The thickness of the gadolinium oxide-doped cerium oxide layer is 1000-2000 nm.

[0018] In some embodiments, the DC magnetron sputtering process also satisfies the following condition: argon partial pressure is 70%-90%.

[0019] In some embodiments, the target material used in the DC magnetron sputtering process is a GdCe alloy target with a purity ≥99.9wt% and a density ≥6.69g / cm³. 3 Optionally, the purity of the GdCe alloy target is 99.90 wt% or 99.95 wt%, etc. Optionally, the density of the GdCe alloy target is 6.69 g / cm³. 3 Or 6.70 g / cm 3 .

[0020] In some embodiments, the substrate is glass with an alkali content ≤0.05wt% and a coefficient of thermal expansion ≤35.5×10⁻⁶ at 25°C. -7 / K, with a thickness of 0.2-1.1 mm. Optionally, the alkali content of the substrate is 0.05 wt% or 0.02 wt%, etc. Optionally, the coefficient of thermal expansion of the substrate at 25°C is 35.5 × 10⁻⁶. -7 / K or 30×10 -7 / K etc.

[0021] In some embodiments, before preparing the gadolinium oxide-doped cerium oxide layer, the substrate is first cleaned. The substrate cleaning steps include: ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water in sequence, and then drying with at least one of nitrogen and inert gas.

[0022] This application also provides a method for preparing the gadolinium-doped cerium oxide thin film, and the gadolinium-doped cerium oxide thin film obtained therefrom.

[0023] This application further provides the application of the gadolinium oxide-doped cerium oxide thin film in solid fuel cell electrolytes.

[0024] Compared with the prior art, the beneficial effects of this application are as follows: This application prepares a gadolinium oxide-doped cerium oxide layer by using a DC magnetron sputtering process with a specific growth temperature, and performs a first annealing and a second annealing in a specific gas atmosphere after the DC magnetron sputtering process, which effectively improves the adhesion of the gadolinium oxide-doped cerium oxide layer on the substrate and makes it stable, making the resulting film suitable for use as a solid fuel cell electrolyte, especially suitable for use as a medium-temperature solid fuel cell electrolyte. Attached Figure Description

[0025] Figure 1 It serves as an adhesion test evaluation standard;

[0026] Figure 2 Here is a scanning electron microscope (SEM) image of the thin film obtained in Example 1;

[0027] Figure 3 The image shows a scanning electron microscope (SEM) image of the thin film obtained in Comparative Example 1.

[0028] Figure 4 The image shows the X-ray diffraction (XRD) pattern of the thin film obtained in Example 1. Detailed Implementation

[0029] To better illustrate the purpose, technical solutions, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than limiting it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are commonly used reagents and instruments. In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0030] Example 1

[0031] This embodiment provides a method for preparing gadolinium oxide-doped cerium oxide thin films, including the following steps:

[0032] The sputtering device is a GdCe alloy with a purity of 99.9 wt% and a density of 6.69 g / cm³. 3 ;

[0033] Glass was used as the substrate, with an alkali content of 0.05 wt% and a coefficient of thermal expansion of 35.5 × 10⁻⁶ at 25°C. -7 / K, with a thickness of 0.6mm, was first ultrasonically cleaned with acetone, then ultrasonically cleaned with anhydrous ethanol, then ultrasonically cleaned with deionized water, and finally dried with nitrogen to obtain the cleaned substrate.

[0034] Using the above-mentioned target material and employing a DC magnetron sputtering process, a gadolinium oxide-doped cerium oxide layer is prepared on one side of a cleaned substrate. This DC magnetron sputtering process satisfies the following requirements:

[0035] The distance between the center of the target and the center of the substrate is 7 cm.

[0036] The oxygen partial pressure is 15%.

[0037] The partial pressure of argon is 85%.

[0038] The sputtering power density of the target is 5 W / cm². 2 ,

[0039] The sputtering pressure is 0.6 Pa.

[0040] The growth temperature is 100℃.

[0041] The gadolinium oxide-doped cerium oxide layer has a thickness of 1200 nm;

[0042] After DC magnetron sputtering, a first annealing is performed in a first gas atmosphere, followed by a second annealing in a second gas atmosphere. The first gas consists of argon and oxygen, with an argon partial pressure of 85% and an oxygen partial pressure of 15%. The first annealing meets the following conditions: temperature 350℃, time 2 hours, and pressure 0.6 Pa. The second gas is air, and the second annealing meets the following conditions: temperature 500℃, time 2.5 hours, and pressure 5 × 10⁻⁶ Pa. 4 Pa.

[0043] Example 2

[0044] This embodiment provides a method for preparing gadolinium oxide-doped cerium oxide thin films, including the following steps:

[0045] The sputtering device is a GdCe alloy with a purity of 99.9 wt% and a density of 6.69 g / cm³. 3 ;

[0046] Glass was used as the substrate, with an alkali content of 0.05 wt% and a coefficient of thermal expansion of 35.5 × 10⁻⁶ at 25°C. -7 / K, with a thickness of 0.2mm, was first ultrasonically cleaned with acetone, then ultrasonically cleaned with anhydrous ethanol, then ultrasonically cleaned with deionized water, and finally dried with nitrogen to obtain the cleaned substrate.

[0047] Using the above-mentioned target material and employing a DC magnetron sputtering process, a gadolinium oxide-doped cerium oxide layer is prepared on one side of a cleaned substrate. This DC magnetron sputtering process satisfies the following requirements:

[0048] The distance between the center of the target and the center of the substrate is 6 cm.

[0049] The partial pressure of oxygen is 10%.

[0050] Argon partial pressure is 90%.

[0051] The sputtering power density of the target is 2.5 W / cm². 2 ,

[0052] The sputtering pressure is 0.4 Pa.

[0053] The growth temperature is 80℃.

[0054] The gadolinium oxide-doped cerium oxide layer has a thickness of 1100 nm;

[0055] After DC magnetron sputtering, a first annealing is performed in a first gas atmosphere, followed by a second annealing in a second gas atmosphere. The first gas consists of argon and oxygen, with an argon partial pressure of 90% and an oxygen partial pressure of 10%. The first annealing meets the following conditions: temperature 300℃, time 5 h, and pressure 0.4 Pa. The second gas is air, and the second annealing meets the following conditions: temperature 400℃, time 3 h, and pressure 1 × 10⁻⁶ Pa. 4Pa.

[0056] Example 3

[0057] This embodiment provides a method for preparing gadolinium oxide-doped cerium oxide thin films, including the following steps:

[0058] The sputtering device is a GdCe alloy with a purity of 99.9 wt% and a density of 6.69 g / cm³. 3 ;

[0059] Glass was used as the substrate, with an alkali content of 0.05 wt% and a coefficient of thermal expansion of 35.5 × 10⁻⁶ at 25°C. -7 / K, with a thickness of 1.1mm, was first ultrasonically cleaned with acetone, then ultrasonically cleaned with anhydrous ethanol, then ultrasonically cleaned with deionized water, and finally dried with nitrogen to obtain the cleaned substrate.

[0060] Using the above-mentioned target material and employing a DC magnetron sputtering process, a gadolinium oxide-doped cerium oxide layer is prepared on one side of a cleaned substrate. This DC magnetron sputtering process satisfies the following requirements:

[0061] The distance between the center of the target and the center of the substrate is 10cm.

[0062] The partial pressure of oxygen is 30%.

[0063] The partial pressure of argon is 70%.

[0064] The sputtering power density of the target is 5.5 W / cm². 2 ,

[0065] The sputtering pressure is 0.8 Pa.

[0066] The growth temperature is 200℃.

[0067] The gadolinium oxide-doped cerium oxide layer has a thickness of 1000 nm;

[0068] After DC magnetron sputtering, a first annealing is performed in a first gas atmosphere, followed by a second annealing in a second gas atmosphere. The first gas consists of argon and oxygen, with an argon partial pressure of 70% and an oxygen partial pressure of 30%. The first annealing meets the following conditions: temperature 600℃, time 2 hours, and pressure 0.8 Pa. The second gas is air, and the second annealing meets the following conditions: temperature 600℃, time 2 hours, and pressure 1×10⁻⁶ Pa. 5 Pa.

[0069] Example 4

[0070] This embodiment provides a method for preparing a gadolinium oxide-doped cerium oxide thin film, which differs from Embodiment 1 in that the temperature of the first annealing is 800°C.

[0071] Example 5

[0072] This embodiment provides a method for preparing a gadolinium oxide-doped cerium oxide thin film, which differs from Embodiment 1 in that the temperature of the second annealing is 800°C.

[0073] Example 6

[0074] This embodiment provides a method for preparing a gadolinium oxide-doped cerium oxide thin film, which differs from Embodiment 1 in that the first annealing time is 1 hour.

[0075] Example 7

[0076] This embodiment provides a method for preparing a gadolinium oxide-doped cerium oxide thin film, which differs from Embodiment 1 in that the second annealing time is 1 hour.

[0077] Example 8

[0078] This embodiment provides a method for preparing a gadolinium oxide-doped cerium oxide thin film, which differs from Embodiment 1 in that the partial pressure of argon in the first gas is 95% and the partial pressure of oxygen is 5%.

[0079] Example 9

[0080] This embodiment provides a method for preparing a gadolinium oxide-doped cerium oxide thin film, which differs from Embodiment 1 in that the partial pressure of argon in the first gas is 65% and the partial pressure of oxygen is 35%.

[0081] Comparative Example 1

[0082] This comparative example provides a method for preparing a gadolinium oxide-doped cerium oxide thin film, which differs from Example 1 in that a second annealing is not performed.

[0083] Comparative Example 2

[0084] This comparative example provides a method for preparing a gadolinium oxide-doped cerium oxide thin film, which differs from Example 1 in that a first annealing is not performed.

[0085] Comparative Example 3

[0086] This comparative example provides a method for preparing gadolinium oxide-doped cerium oxide thin films, which differs from Example 1 in that the first annealing is replaced with air annealing, and the annealing meets the following conditions: pressure 1×10⁻⁶. 5 Pa, temperature 350℃, time 2h.

[0087] Comparative Example 4

[0088] This comparative example provides a method for preparing gadolinium oxide-doped cerium oxide thin films, which differs from Example 1 in that the growth temperature of the DC magnetron sputtering process is 25°C.

[0089] Comparative Example 5

[0090] This comparative example provides a method for preparing gadolinium oxide-doped cerium oxide thin films, which differs from Example 1 in that the growth temperature of the DC magnetron sputtering process is 250°C.

[0091] The gadolinium oxide-doped cerium oxide films obtained in the above embodiments and comparative examples were tested as follows:

[0092] (1) Adhesion test: Cross-cut adhesion test, using 3M 600 tape. The test evaluation criteria are as follows: Figure 1 ;

[0093] (2) Appearance test: Scanning electron microscopy test to observe whether there are abnormal phenomena such as bubbles, raised particles, cracks, etc. on the surface of the film;

[0094] (3) Stability test: Place the film at 25℃ and 70%RH for one week and observe whether the film peels off. Record the time when peeling occurs.

[0095] (4) X-ray diffraction test.

[0096] Some test results are shown in Table 1. Figures 2-4 .

[0097] Table 1

[0098] serial number Adhesion SEM morphology stability Example 1 5B No obvious abnormalities The thin film remained unchanged. Example 2 5B No obvious abnormalities The thin film remained unchanged. Example 3 5B No obvious abnormalities The thin film remained unchanged. Example 4 2B Bubbles on the surface of the film The film peeled off after 67 hours. Example 5 3B Bubbles on the surface of the film The film peeled off after 65 hours. Example 6 2B Bubbles on the surface of the film The film peeled off after 24 hours. Example 7 3B Bubbles on the surface of the film The film peeled off after 72 hours. Example 8 2B The film surface has raised particles The film peeled off after 25 hours. Example 9 2B The film surface has raised particles The film peeled off after 27 hours. Comparative Example 1 1B Film peeling cannot be observed The film peeled off after 10 minutes. Comparative Example 2 1B Film peeling cannot be observed The film peeled off after 5 minutes. Comparative Example 3 1B Film peeling cannot be observed The film peeled off after 2 minutes. Comparative Example 4 1B Film peeling cannot be observed The film peeled off after 30 seconds. Comparative Example 5 1B Film peeling cannot be observed The film peeled off after 20 minutes.

[0099] As can be seen from the above data, the gadolinium oxide-doped cerium oxide films prepared in the various embodiments of this application have an adhesion of 2B to 5B and do not fall off after being stored at 25°C for more than 23 hours.

[0100] Comparative Examples 1 and 2 had poor adhesion and stability because they were only annealed once.

[0101] Comparative Example 3, due to only undergoing air annealing, exhibited poor adhesion and stability.

[0102] Comparative Examples 4 and 5 showed poor adhesion and stability due to excessively low or high growth temperatures.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A method for preparing a gadolinium oxide-doped cerium oxide thin film, characterized in that, Includes the following steps: A gadolinium oxide-doped cerium oxide layer is prepared on at least one side of a substrate using a DC magnetron sputtering process, wherein the growth temperature is 80-200℃; A first annealing is performed in a first gas atmosphere, followed by a second annealing in a second gas atmosphere to obtain a gadolinium oxide-doped cerium oxide film. The first gas includes at least one of nitrogen, an inert gas, and oxygen, and the second gas is air. The first annealing process meets the following requirements: temperature 250-650℃, time 2-5 h, and pressure 0.4-0.8 Pa. The second annealing process meets the following requirements: temperature 350-650℃, time 2-3 h, and pressure 1×10⁻⁶. 4 -1×10 5 Pa.

2. The method for preparing gadolinium oxide-doped cerium oxide thin films as described in claim 1, characterized in that, The oxygen partial pressure in the first gas is 10%-30%.

3. The method for preparing gadolinium oxide-doped cerium oxide thin films as described in claim 1, characterized in that, The DC magnetron sputtering process satisfies: The distance between the center of the target and the center of the substrate is 6-10 cm; The partial pressure of oxygen is 10%-30%; The sputtering power density of the target is 2.5-5.5 W / cm³. 2 ; The sputtering pressure is 0.4-0.8 Pa; The thickness of the gadolinium oxide-doped cerium oxide layer is 1000-2000 nm.

4. The method for preparing gadolinium oxide-doped cerium oxide thin films as described in claim 1, characterized in that, The target material used in the DC magnetron sputtering process is a GdCe alloy target material with a purity ≥99.9wt% and a density ≥6.69g / cm³.

5. The method for preparing gadolinium oxide-doped cerium oxide thin films as described in claim 1, characterized in that, The substrate is glass with an alkali content ≤0.05wt% and a coefficient of thermal expansion ≤35.5×10⁻⁶ at 25℃. -7 / K, with a thickness of 0.2-1.1 mm.

6. The method for preparing gadolinium oxide-doped cerium oxide thin films as described in claim 1, characterized in that, Before preparing the gadolinium oxide-doped cerium oxide layer, the substrate is first cleaned. The substrate cleaning steps include: ultrasonic cleaning with acetone, anhydrous ethanol and deionized water in sequence, and then drying with at least one of nitrogen and inert gas.

7. A gadolinium-doped cerium oxide thin film prepared by the method for preparing gadolinium-doped cerium oxide thin films according to any one of claims 1 to 6.

8. The application of the gadolinium oxide-doped cerium oxide thin film as described in claim 7 in solid fuel cell electrolytes.

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