Preparation method of anode-supported gdc electrolyte thin film based on cvd and solid oxide fuel cell

Abstract

The application discloses a preparation method of an anode-supported GDC electrolyte film based on CVD and a solid oxide fuel cell. The anode support is cleaned; the anode support is preheated; a precursor is subjected to gasification treatment; the gasified precursor is subjected to chemical vapor deposition on the surface of the preheated anode support to form a dense electrolyte film; the precursor is tetrakis(2,2,6,6-tetramethyl-3,5-heptanedione) cerium and tris(2,2,6,6-tetramethyl-3,5-heptanedione) gadolinium; a cathode slurry is prepared; the cathode material is a perovskite material La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3‑δ ; the slurry is coated on the surface of the above structure by using a silk screen printing method, dried in a drying box for a certain period of time, and then placed in a muffle furnace to perform high-temperature sintering; the anode support NiO-GDC is reduced to Ni-GDC at a certain temperature, and the complete reduction end point is that the OCV stability or the polarization curve is no longer improved; the prepared battery can work under the condition of 500-800 DEG C, the material requirement and cost are reduced, and the service life of the battery is improved.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide fuel cells (SOFC), specifically relating to a method for preparing GDC electrolyte films and SOFC single cells based on chemical vapor deposition (CVD) technology. Background Technology

[0002] Solid oxide fuel cells (SOFCs) have emerged as a sustainable energy solution to replace thermal power generation due to their advantages such as high energy conversion efficiency, wide fuel adaptability, and environmental friendliness. Based on operating temperature, SOFCs are generally classified into three types: high-temperature fuel cells (above 800 °C), medium-temperature fuel cells (600–800 °C), and low-temperature fuel cells (below 600 °C). High-temperature fuel cell technology is currently mature. However, operating at high temperatures reduces battery lifespan and durability, and also increases material and manufacturing costs. These unavoidable problems hinder the commercialization of high-temperature SOFCs. Therefore, current research on fuel cells focuses on reducing the operating temperature to medium or low temperatures.

[0003] Most low- and medium-temperature fuel cells employ porous electrode supports and dense electrolyte membrane structures. Currently, the mainstream methods for preparing electrolyte membranes are casting and screen printing. These two methods are simple to operate, low-cost, and easy to industrialize, but they struggle to achieve high-density electrolyte membranes. However, solid oxide fuel cells (SOFCs) require high electrolyte density to effectively prevent fuel and oxidant permeation while ensuring efficient ion conduction, thereby improving battery output performance and stability. Therefore, there is an urgent need for a membrane fabrication technology that can stably and efficiently prepare a dense electrolyte layer on the surface of porous electrodes, and use this as a basis for fabricating low- and medium-temperature solid oxide fuel cells. Summary of the Invention

[0004] This invention proposes a method for preparing a solid oxide fuel cell that can operate in low to medium temperature environments, belonging to the field of solid oxide fuel cells.

[0005] include: (1) Provide a porous anode support.

[0006] (2) The anode support is preheated.

[0007] (3) The raw material containing the metal-organic precursor is gasified to obtain the gaseous precursor.

[0008] (4) The gaseous precursor is transported to the surface of the preheated anode support, and a dense electrolyte film is formed on the surface of the anode support by chemical vapor deposition. The precursor is tetratetra(2,2,6,6-tetramethyl-3,5-heptadecyl)cerium (Ce(DPM)4) and tris(2,2,6,6-tetramethyl-3,5-heptadecyl)gadolinium (Gd(DPM)3).

[0009] (5) Preparation of cathode paste; the cathode material is perovskite material La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF); The slurry is applied to the surface of the above structure by screen printing, dried in a drying oven for a certain period of time, and then placed in a muffle furnace for high-temperature sintering.

[0010] (6) The anode support NiO-GDC is reduced to Ni-GDC at a certain temperature, and the complete reduction endpoint is when the OCV stabilizes or the polarization curve no longer increases; thus forming a solid oxide fuel cell that can work in medium and low temperature environments.

[0011] This invention is applied to the field of solid oxide fuel cells, solving the problem of the difficulty in preparing high-density electrolyte films using traditional methods. Furthermore, the cells prepared by this method can operate at 500-800 °C, reducing material requirements and costs while improving battery lifespan.

[0012] To address the aforementioned problems, the present invention aims to provide a CVD-based anode-supported dense GDC electrolyte film preparation technology, which can stably and efficiently prepare a dense GDC electrolyte layer on the surface of a porous electrode, thus solving the problem that current mainstream preparation technologies are unable to achieve high-density electrolyte film preparation.

[0013] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows: This invention provides a method for preparing a dense GDC electrolyte layer, and based on this structure, prepares a cathode to form a solid oxide fuel cell that can operate in medium and low temperature environments.

[0014] The battery is manufactured using the following steps: (1) The anode support is ultrasonically cleaned using acetone / ethanol. The anode support is a NiO-GDC ceramic substrate. (2) Preheat the pretreated anode support; (3) The precursor is vaporized and then chemically vapor-deposited on the surface of the preheated anode support to form a dense electrolyte film; the precursor is tetra(2,2,6,6-tetramethyl-3,5-heptadecyl)cerium and tris(2,2,6,6-tetramethyl-3,5-heptadecyl)gadolinium; (4) The slurry is applied to the surface of the electrolyte film structure using screen printing. After drying in a drying oven for a certain period of time, it is placed in a muffle furnace for high-temperature sintering. The slurry is prepared by mixing cathode material powder and organic binder in a certain mass ratio and grinding them in a ball mill. The cathode material is perovskite material La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF); (5) The sintered battery structure is placed in a mixture of H2 / N2 or H2 / Ar gas and reduced at a certain temperature to reduce the anode support NiO-GDC to Ni-GDC. The complete reduction endpoint is when the OCV stabilizes or the polarization curve no longer increases. A solid oxide fuel cell that can work in a medium and low temperature environment is formed.

[0015] Preferably, the porosity of the anode support is between 20% and 80%.

[0016] Preferably, the ultrasonic cleaning time is 15-30 min.

[0017] Preferably, the preheating temperature of the anode support is 600-800 ℃.

[0018] Preferably, the precursor vaporization treatment temperature is 300-400 ℃.

[0019] Preferably, the chemical vapor deposition is carried out in a reaction chamber, and the gaseous precursor is transported into the reaction chamber by a carrier gas; the carrier gas is one or more of N2, Ar, and He2.

[0020] Preferably, the deposition time is between 30 and 180 minutes, more preferably 60 to 120 minutes. The feed flow rate is 0.9 to 1.8 g / min. The higher the feed flow rate, the longer the deposition time, and the thicker the film, which can be controlled between 300 and 3000 nm.

[0021] Preferably, the Gd(DPM)3 doping amount is between 10-30 mol%.

[0022] Preferably, the grinding time is 30-60 min.

[0023] Preferably, the drying temperature is 40-60 ℃ and the drying time is 60-180 min.

[0024] Preferably, the high-temperature sintering temperature is 900-1300 ℃ and the sintering time is 90-120 min.

[0025] Preferably, the hydrogen content in the mixed gas is 3-10 mol%, and the reduction temperature is 600-800 ℃.

[0026] Compared with the prior art, the advantages of this invention are: This invention provides a method for preparing a dense GDC electrolyte film on the surface of a porous anode support. The method uses chemical vapor deposition to modify the surface of a porous NiO-GDC ceramic substrate. The thickness of the electrolyte film can be precisely controlled by controlling the deposition time and the raw material flow rate. The prepared electrolyte film has the advantages of high density and high uniformity.

[0027] Furthermore, this method enables atomic-level interfacial fusion between the electrolyte and the anode support, reducing interfacial ohmic resistance and completely resolving the interfacial cracking and element interdiffusion problems inherent in traditional wet processes. Based on this structure, a solid oxide fuel cell structure capable of operating at medium to low temperatures is proposed. This cell can operate at 500-800 °C, reducing material requirements and costs while improving battery lifespan. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating the principle of preparing dense GDC electrolyte films by chemical vapor deposition according to the present invention.

[0029] Figure 2 This is a cross-sectional schematic diagram of the low-temperature solid oxide fuel cell of the present invention. In the figure, the markings are: 1-anode support, 2-GDC electrolyte layer, 3-cathode layer.

[0030] Figure 3 This is a SEM image of a dense GDC film prepared by chemical vapor deposition for 30 min at a temperature of 800 ℃ and a pressure of 3000 Pa.

[0031] Figure 4 This is a flowchart illustrating the method for preparing a low-temperature solid oxide fuel cell in this invention. Detailed Implementation

[0032] Example 1 like Figure 2 As shown, the medium-low temperature solid oxide fuel cell includes a Ni-based anode ceramic support 1, a GDC electrolyte layer 2, and a cathode layer 3.

[0033] The solid oxide fuel cell fabrication method in this example is as follows: (1) A NiO-GDC ceramic sheet with a thickness of 30 μm and a porosity of about 60% was selected as the anode support 1. It was placed in a mixed solution of acetone and ethanol, ultrasonically cleaned for 15 minutes to remove surface oil and impurities, and then dried for later use.

[0034] (2) The cleaned anode support 1 was placed in the CVD reaction chamber and preheated to 800 °C at a heating rate of 10 °C / min under Ar protection. Simultaneously, a mixture of tetra(2,2,6,6-tetramethyl-3,5-heptadecyl)cerium and tris(2,2,6,6-tetramethyl-3,5-heptadecyl)gadolinium (Gd doping amount of 20 mol%) was fed into the vaporization chamber at a flow rate of 1.5 g / min and heated to 300 °C for vaporization. Ar gas was used as the carrier gas to carry the gaseous precursor into the reaction chamber. At a deposition temperature of 800 °C, the deposition time was maintained for 30 minutes to form a dense GDC electrolyte layer 2 on the surface of the anode support 1. The electrolyte layer had a thickness of 732 nm, resulting in a NiO-GDC / GDC composite structure.

[0035] (3) La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) cathode powder and ethyl cellulose binder were mixed at a mass ratio of 7:3, with an appropriate amount of terpineol added as a solvent. The mixture was ball-milled at 300 rpm for 30 minutes to obtain a uniform cathode slurry. The slurry was then screen-printed onto the surface of the GDC electrolyte layer 2 and dried in a drying oven at 60 °C for 60 minutes. Subsequently, the sample was placed in a muffle furnace and heated to 1100 °C at a heating rate of 5 °C / min, and sintered for 2 hours to form the cathode layer 3.

[0036] (4) The sintered battery semi-finished product is placed in a tube furnace, and a mixed gas of 10% H2 / 90% N2 is introduced. The mixture is heated to 650 °C at a heating rate of 5 °C / min and reduced for 2 hours. During this process, NiO in the anode support 1 is reduced to metallic Ni to form a porous Ni-GDC anode.

[0037] Battery performance testing: The prepared single cells were subjected to electrochemical performance testing in an H2 / N2 or H2 / Ar mixed atmosphere at an operating temperature of 700 °C. The test results show that at an operating temperature of 700 °C, the open-circuit voltage of the battery is close to the theoretical value, and the maximum power density reaches 0.57 W / cm². 2 The corresponding current density is 1.25 A / cm². 2 It demonstrates excellent power generation performance.

[0038] Example 2 The difference from Example 1 is that the deposition temperature of GDC electrolyte layer 2 is 600 °C, the flow rate of the mixture of tetra(2,2,6,6-tetramethyl-3,5-heptadecyl)cerium and tris(2,2,6,6-tetramethyl-3,5-heptadecyl)gadolinium is 1.1 g / min, and the thickness of the resulting electrolyte layer is 1320 nm.

[0039] The resulting single cell achieved a maximum power density of 0.52 W / cm³ at an operating temperature of 700 °C. 2 The corresponding current density is 1.13 A / cm². 2 .

[0040] Example 3 The difference from Example 1 is that the mixture of tetra(2,2,6,6-tetramethyl-3,5-heptanedione)cerium and tri(2,2,6,6-tetramethyl-3,5-heptanedione)gadolinium contains 10 mol of tri(2,2,6,6-tetramethyl-3,5-heptanedione)gadolinium.

[0041] The resulting single cell achieved a maximum power density of 0.55 W / cm³ at an operating temperature of 700 °C. 2 The corresponding current density is 1.21 A / cm². 2 .

[0042] Example 4 The difference from Example 1 is that the deposition temperature of GDC electrolyte layer 2 is 500°C, and the thickness of the resulting electrolyte layer is 1575 nm.

[0043] The resulting single cell achieved a maximum power density of 0.17 W / cm³ at an operating temperature of 700 °C. 2 The corresponding current density is 0.38 A / cm. 2 .

[0044] Example 5 The difference from Example 1 is that the mixture of tetra(2,2,6,6-tetramethyl-3,5-heptadecyl)cerium and tri(2,2,6,6-tetramethyl-3,5-heptadecyl)gadolinium contains 5 mol of tri(2,2,6,6-tetramethyl-3,5-heptadecyl)gadolinium.

[0045] The resulting single cell achieved a maximum power density of 0.15 W / cm³ at an operating temperature of 700 °C. 2 The corresponding current density is 0.32 A / cm. 2 .

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an anode-supported GDC electrolyte thin film based on CVD, characterized in that, Includes the following steps: (1) Provide a porous anode support; (2) The anode support is preheated; (3) The raw material containing the metal-organic precursor is gasified to obtain the gaseous precursor; (4) The gaseous precursor is transported to the surface of the preheated anode support, and a dense electrolyte film is formed on the surface of the anode support by chemical vapor deposition.

2. The method for preparing an anode-supported GDC electrolyte thin film based on CVD according to claim 1, characterized in that, The anode support is a NiO-GDC ceramic substrate with a porosity of 20%-80%.

3. The method for preparing an anode-supported GDC electrolyte thin film based on CVD according to claim 2, characterized in that, The preheating temperature is 600-800℃.

4. The method for preparing an anode-supported GDC electrolyte thin film based on CVD according to claim 1, characterized in that, The organometallic precursor is selected from tetra(2,2,6,6-tetramethyl-3,5-heptadecyl)cerium and tris(2,2,6,6-tetramethyl-3,5-heptadecyl)gadolinium, wherein the proportion of tris(2,2,6,6-tetramethyl-3,5-heptadecyl)gadolinium is between 10-30 mol%; the temperature of the gasification treatment is 300-400 °C.

5. The method for preparing an anode-supported GDC electrolyte thin film based on CVD according to claim 1, characterized in that, The deposition temperature is 600-800 ℃, preferably 600 ℃; the deposition time is between 30-180 minutes, preferably 60-120 minutes; the raw material flow rate is 0.9-1.8 g / min; and the thickness can be controlled between 300-3000 nm.

6. The method for preparing an anode-supported GDC electrolyte thin film based on CVD according to claim 1, characterized in that, The gaseous precursor is transported to the surface of the anode support by a carrier gas, which is an inert gas, including one or more of N2, Ar, and He.

7. A method for preparing a solid oxide fuel cell, characterized in that, Includes the following steps: Using the preparation method described in any one of claims 1-6, a dense electrolyte film is formed on the surface of a porous anode support to obtain an anode support-electrolyte layer composite structure. A cathode layer is prepared on the surface of the electrolyte film to obtain a battery semi-finished product; The battery semi-finished product is placed in a reducing atmosphere for reduction treatment, so that the metal oxide in the anode support is partially or completely reduced to elemental metal to form an anode.

8. The preparation method according to claim 7, characterized in that, The method for preparing the cathode layer includes: mixing and grinding a cathode material with a binder to form a slurry; coating the slurry onto the surface of an electrolyte film; and drying and sintering at high temperature to form the cathode layer. The cathode material is a perovskite-type material with the chemical formula La. 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ The high-temperature sintering temperature is 900-1300 ℃, the sintering time is 90-120 minutes, the reducing atmosphere is a mixture of H2 and N2 or H2 and Ar, wherein the volume percentage of hydrogen is 3-10%; the reduction temperature is 600-800 ℃.

9. A solid oxide fuel cell, characterized in that, include: Porous anode support; A dense electrolyte film, which is formed directly on the surface of the anode support by chemical vapor deposition; A cathode layer is disposed on the surface of the electrolyte film; The electrolyte film is made of doped cerium oxide.

10. The solid oxide fuel cell according to claim 9, characterized in that, An atomic-level fusion interface is formed between the electrolyte film and the anode support.

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