A method for improving the interface contact of a solid state oxide electrolyte with a low melting point metal oxide

Abstract

The application discloses a method for improving interface contact of a solid-state oxide electrolyte by a low-melting-point metal oxide, and comprises the following steps: preparing a porous electrode support layer; dip-coating a solid-state oxide electrolyte film; modifying the electrolyte interface by a metal oxide; and preparing a porous air electrode. By simply introducing a low-melting-point metal oxide, the surface activity of a high-temperature sintered electrolyte is improved, so that the electrolyte can be sintered with an air electrode at a suitable temperature to generate a three-phase interface, while the structure and performance of the air electrode can be maintained, the binding force between the electrolyte and the air electrode is enhanced, the interface resistance caused by poor contact is significantly reduced, the inherent conductivity of the electrolyte is recovered, and the performance of a battery is comprehensively improved.

Description

Technical Field

[0001] This invention relates to the field of solid oxide film interface technology, and more specifically, to a method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides. Background Technology

[0002] Solid oxide membranes (SOMs), with their all-solid-state structure, allow only specific ions (such as oxygen ions and protons) to pass through, playing a crucial role in numerous fields such as electrochemistry and separation technology, and are an important component of clean energy. However, insufficient solid-solid interface contact between SOMs and catalysts hinders ion transport during operation, affecting the overall membrane performance. Therefore, improving the interface contact is essential for enhancing SOM performance and achieving large-scale production.

[0003] Among them, proton-conducting ceramic films mainly conduct protons in the mid-temperature range of 400℃ to 700℃, and are currently an important area of ​​research in solid oxide films. However, the ohmic resistance of electrolyte films in electrochemical cells is much larger than the theoretical value calculated from volume ionic conductivity, proving that there is a large contact resistance between the film and electrolyte interface. Choi et al. deposited a dense cathode transition layer on the electrolyte surface, which significantly reduced the interfacial ohmic resistance. In addition, constructing some special electrode structures can increase the contact area, such as three-dimensional fiber electrodes, thereby reducing the impedance between the electrolyte and the electrode. High-temperature construction of the electrode framework, followed by impregnation of active electrode materials and low-temperature calcination, is beneficial for maintaining both interfacial contact and electrode activity. In addition, physical methods to improve interfacial contact mainly include laser etching and plasma treatment. However, current interface modification methods still face problems such as limited improvement effect, low operability, and unsuitability for large-area preparation. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a method for improving the interfacial contact of solid oxide electrolytes with low-melting-point metal oxides. This invention improves the interfacial contact between the electrolyte and the electrode by simply introducing low-melting-point metal oxides at the solid electrolyte interface, so that the two can sinter at a suitable temperature to form a three-phase interface, thereby reducing the interfacial contact resistance and improving the overall performance of the battery.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for improving the interfacial contact of a solid oxide electrolyte using a low-melting-point metal oxide includes the following steps:

[0007] (1) A porous hydrogen electrode support layer was prepared by casting method and the organic matter was removed by pre-calcination at 800℃~1000℃ to obtain a porous electrode support layer.

[0008] (2) The electrolyte powder is prepared into an electrolyte slurry and dipped onto the surface of the porous electrode support layer. The slurry is then calcined at 1450℃~1500℃ to form a solid oxide electrolyte film on the surface of the porous electrode support layer, thus obtaining a half cell.

[0009] (3) The metal oxide precursor liquid is introduced into the surface of the solid oxide electrolyte film of the half cell and calcined at 850°C to 900°C to form a metal oxide modified electrolyte interface.

[0010] (4) The air electrode powder is made into an electrode slurry and brushed onto the metal oxide modified electrolyte interface and calcined once at 900℃~950℃ to obtain a porous electrode framework. Then, the nitrate of the nano active electrode is made into a precursor liquid and repeatedly added to the porous electrode framework. The porous air electrode framework and nano active electrode composite structure are obtained by calcination at 700℃~800℃.

[0011] Optionally, in step (1), the hydrogen electrode support layer comprises an electrolyte material BaZr with a mass ratio of (4-5):(5-6):2. 0.85 Y 0.15 O 3-δ (BZY), NiO and pore-forming agent spherical graphite, preferably in a mass ratio of 5:5:2 or 4:6:2.

[0012] Optionally, in step (1), the preheating time is 2h to 3h.

[0013] Optionally, in step (2), the solid content of the electrolyte slurry is 20wt% to 25wt%; the electrolyte slurry is a solution containing electrolyte powder and additives; and the solvent in the electrolyte slurry is anhydrous ethanol and butanone.

[0014] Optionally, the additives include butyl benzyl phthalate, triethanolamine, and polyethylene glycol butyral.

[0015] Optionally, in step (2), the pressure for impregnation includes atmospheric pressure or negative pressure.

[0016] Optionally, in step (2), the calcination time is 6h to 10h.

[0017] Optionally, in step (2), the thickness of the solid oxide electrolyte film is 20 μm to 30 μm, preferably 20 μm.

[0018] Optionally, in step (3), the metal oxide in the metal oxide precursor solution includes CuO or (Y) 0.25 Bi 0.75 )2O3(YSB).

[0019] Optionally, in step (3), the metal oxide precursor solution includes a nitrate solution of metal oxide or an ethanol dispersion of metal oxide nanoparticles.

[0020] Optionally, in step (3), when the metal oxide precursor solution is a nitrate solution of the metal oxide, the nitrate solution of the metal oxide is mixed with citric acid to prepare the metal oxide precursor solution.

[0021] Optionally, in step (3), the concentration of metal ions in the metal oxide precursor solution is 0.05 mol / L to 0.2 mol / L.

[0022] Optionally, in step (3), the introduction includes thermal droplet coating or thermal spraying.

[0023] Optionally, in step (3), the calcination time is 1h to 2h.

[0024] Optionally, in step (4), the air electrode is PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF)

[0025] Optionally, in step (4), the air electrode is mixed with ethyl cellulose and terpineol in a mass ratio of 1:(0.15-0.2):(0.8-0.85) to prepare an electrode slurry. Preferably, the mass ratio is 1:0.15:0.85 or 1:0.2:0.8.

[0026] Optionally, in step (4), the nano-active electrode is PrBaCo2O 5+δ (PBC); The precursor solution is prepared by mixing the nitrate of the nano-active electrode with citric acid, wherein the concentration of metal ions is 0.2 mol / L to 0.5 mol / L.

[0027] Optionally, in step (4), the time for the first calcination is 2h to 3h, and the time for the second calcination is 2h to 3h.

[0028] Implementing the embodiments of the present invention will have the following beneficial effects:

[0029] This invention improves the surface activity of a high-temperature sintering electrolyte by simply introducing low-melting-point metal oxides such as CuO or YSB. This allows the electrolyte to sinter with an active air electrode at a suitable temperature, expanding the three-phase interface while maintaining the structure and performance of the air electrode. This strategy enhances the adhesion between the electrolyte and the air electrode, significantly reducing interfacial resistance caused by poor contact. This helps restore the inherent conductivity of the BZY electrolyte and comprehensively improves the overall battery performance. This simple interface modification method can also provide insights for the interface engineering of other solid oxide electrolytes. Attached Figure Description

[0030] Figure 1 The images show the surface morphology of the electrolyte modified with CuO according to the present invention; (a) shows the modification by the hot drop coating method in step 3 of Example 1; and (b) shows the modification by the hot spraying method in step 3 of Example 2.

[0031] Figure 2 The figures show the performance of the hydrogen-oxygen fuel cell after CuO modification in this invention; (a) is Example 3; (b) is Example 5.

[0032] Figure 3 The following are performance diagrams of the full-cell hydrogen-oxygen fuel cell of Comparative Example 1 (unmodified CuO); (a) shows the power density performance of Comparative Example 1; (b) shows the impedance comparison between Comparative Example 1 and Example 3. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0034] Example 1

[0035] The method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides in this embodiment includes the following steps:

[0036] (1) Preparation of porous electrode support layer: A porous hydrogen electrode support layer is prepared by tape casting. The hydrogen electrode support layer includes electrolyte material BZY, NiO and pore-forming agent spherical graphite in a mass ratio of 5:5:2. The organic matter is removed by pre-calcination at 1000℃ for 2h to obtain the porous electrode support layer.

[0037] (2) Impregnation of proton conductor electrolyte film: Weigh the required BaCO3, ZrO2, and Y2O3 according to the stoichiometric ratio, and add 1wt% NiO as a sintering aid. The solvents are anhydrous ethanol and butanone. Triethanolamine, butyl benzyl phthalate, and polyvinyl butyral are added to prepare an electrolyte slurry with a solid content of 25wt%. The porous electrode support layer prepared in step (1) is repeatedly impregnated with the electrolyte slurry twice under normal pressure. After drying, it is calcined at 1500℃ for 6h to obtain a half-cell electrolyte thickness of about 20μm.

[0038] (3) Modification of the electrolyte interface with metal oxide CuO: A precursor solution was prepared by mixing copper nitrate and citric acid, with a metal ion concentration of 0.2 mol / L and a citric acid concentration 1.5 times that of the metal ions. The half-cell obtained in step (2) was preheated at 100℃, and a 1.3 μL / cm³ electrolyte was added. 2 The precursor solution was added to the electrolyte surface, dried, and then calcined at 900℃ for 1 hour to form a metal oxide-modified electrolyte interface, with a surface morphology as shown. Figure 1 As shown in (a).

[0039] (4) Preparation of porous air electrode: An electrode slurry was prepared by mixing air electrode PBSCF with ethyl cellulose and terpineol at a mass ratio of 1:0.15:0.85. This slurry was brushed onto the electrolyte surface obtained in step (3), dried, and then calcined at 900℃ for 3 hours to obtain the PBSCF electrode framework. A precursor solution was prepared by mixing the nitrate corresponding to PBC with citric acid, with a metal ion concentration of 0.5 mol / L. 1.6 μL / mm... 2 The precursor solution was added dropwise onto the PBSCF framework, and the addition was repeated three times. After drying, the mixture was calcined at 700℃ for 2 hours to obtain an air electrode composed of a porous PBSCF framework and nano-PBC particles.

[0040] Example 2

[0041] The method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides in this embodiment includes the following steps:

[0042] (1) Preparation of porous electrode support layer: Same as step (1) in Example 1.

[0043] (2) Impregnation of proton conductor electrolyte film: Weigh the required BaCO3, ZrO2, and Y2O3 according to the stoichiometric ratio, and add 1wt% NiO as a sintering aid. The solvents are anhydrous ethanol and butanone. Triethanolamine, butyl benzyl phthalate, and polyvinyl butyral are added to prepare an electrolyte slurry with a solid content of 20wt%. The pre-sintered porous electrode support layer prepared in step (1) is impregnated with the electrolyte slurry under negative pressure for 2 minutes. After drying, it is calcined at 1500℃ for 10 hours.

[0044] (3) Electrolyte interface modification with CuO metal oxide: A precursor solution was prepared by mixing copper nitrate and citric acid, with a metal ion concentration of 0.05 mol / L and a citric acid concentration 1.5 times that of the metal ions. The CuO precursor solution was introduced onto the surface of the half-cell obtained in step (2) using a thermal spraying method. The substrate temperature was 100°C during spraying, followed by calcination at 900°C for 1 hour. The surface of the electrolyte after CuO modification was as follows: Figure 1 As shown in (b).

[0045] (4) Preparation of porous air electrode: An electrode slurry was prepared by mixing air electrode PBSCF with ethyl cellulose and terpineol at a mass ratio of 1:0.15:0.85. This slurry was then brushed onto the electrolyte surface obtained in step (3), dried, and calcined at 900℃ for 3 hours. A precursor solution was prepared by mixing the nitrate corresponding to PBC with citric acid, with a metal ion concentration of 0.5 mol / L. This precursor solution was repeatedly added dropwise to the PBSCF framework, with a total addition volume of 4.8 μL / mm. 2 After drying, it is calcined at 700℃ for 2 hours.

[0046] Example 3

[0047] The method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides in this embodiment includes the following steps:

[0048] (1) Preparation of porous electrode support layer: Same as step (1) in Example 1.

[0049] (2) Dip-coating proton conductor electrolyte film: Same as step (2) in Example 1.

[0050] (3) Modification of the electrolyte interface with metal oxide CuO: A precursor solution was prepared by mixing copper nitrate and citric acid, with a metal ion concentration of 0.1 mol / L and a citric acid concentration 1.5 times that of the metal ions. A 3.2 μL / cm³ electrolyte was then applied using a hot drop-coating method. 2 The precursor liquid was drop-added onto the surface of the half-cell obtained in step (2) at a drop coating temperature of 80°C. After drying, it was calcined at 900°C for 1 hour.

[0051] (4) Preparation of porous air electrode: An electrode slurry was prepared by mixing air electrode PBSCF with ethyl cellulose and terpineol at a mass ratio of 1:0.15:0.85. This slurry was then brushed onto the electrolyte surface obtained in step (3), dried, and calcined at 950℃ for 3 hours. A precursor solution was prepared by mixing the nitrate corresponding to PBC with citric acid, with a metal ion concentration of 0.5 mol / L. 1.6 μL / mm... 2 The precursor solution was dropwise added to the PBSCF backbone, repeated three times, dried, and then calcined at 700℃ for 2 hours. Finally, the full cell performance was measured using hydrogen (3% H2O + 97% H2) as fuel and ambient air as oxidant. Figure 3 As shown in (a).

[0052] Example 4

[0053] The method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides in this embodiment includes the following steps:

[0054] (1) Preparation of porous electrode support layer: A porous hydrogen electrode support layer was prepared by casting method, including BZY, NiO and pore-forming agent spherical graphite in a mass ratio of 4:6:2. The support layer was pre-calcined at 1100℃ for 2h to give it a certain strength and remove organic matter.

[0055] (2) Dip-coating proton conductor electrolyte film: Same as step (2) in Example 1.

[0056] (3) Modification of the electrolyte interface with metal oxide YSB: A precursor solution was prepared by mixing yttrium nitrate, bismuth nitrate, and citric acid. The total metal ion concentration was 0.1 mol / L, and the amount of citric acid was 1.5 times the total metal ion concentration. 3.2 μL / cm 2 The precursor liquid was added to the surface of the BZY electrolyte obtained in step (2), dried, and then calcined at 900°C for 1 hour.

[0057] (4) Preparation of porous air electrode: A porous air electrode slurry was prepared by mixing PBSCF with ethyl cellulose and terpineol at a mass ratio of 1:0.15:0.85. This slurry was then brushed onto the electrolyte surface obtained in step (3), dried, and calcined at 850℃ for 3 hours. A precursor solution was prepared by mixing the nitrate corresponding to PBC with citric acid, with a metal ion concentration of 0.5 mol / L. The precursor solution was repeatedly added dropwise to the PBSCF framework, with a total addition volume of 5 μL / mm. 2 After drying, it is calcined at 800℃ for 2 hours.

[0058] Example 5

[0059] The method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides in this embodiment includes the following steps:

[0060] (1) Preparation of porous electrode support layer: Same as step (1) in Example 1.

[0061] (2) Dip-coating proton conductor electrolyte film: Same as step (2) in Example 1.

[0062] (3) Modification of the electrolyte interface with metal oxide CuO: A precursor solution was prepared by mixing copper nitrate and citric acid, with a metal ion concentration of 0.1 mol / L and a citric acid concentration 1.5 times that of the metal ions. A 4.8 μL / cm³ electrolyte was then deposited using a hot drop coating method. 2 The precursor liquid was drop-added onto the surface of the half-cell obtained in step (2) at a drop coating temperature of 80°C. After drying, it was calcined at 900°C for 1 hour.

[0063] (4) Preparation of porous air electrode: An electrode slurry was prepared by mixing air electrode PBSCF with ethyl cellulose and terpineol at a mass ratio of 1:0.1:0.9. This slurry was then brushed onto the electrolyte surface obtained in step (3), dried, and calcined at 950℃ for 3 hours. A precursor solution was prepared by mixing the nitrate corresponding to PBC with citric acid, with a metal ion concentration of 0.5 mol / L. 5 μL / mm... 2 The precursor solution was added droplets to the PBSCF framework, dried, and then calcined at 700°C for 2 hours. The full-cell performance was measured using hydrogen (3% H₂O + 97% H₂) as fuel and ambient air as the oxidant. Figure 3 As shown in (b).

[0064] Example 6

[0065] The method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides in this embodiment includes the following steps:

[0066] (1) Preparation of porous electrode support layer: Same as step (1) in Example 1.

[0067] (2) Dip-coating proton conductor electrolyte film: Same as step (2) in Example 2.

[0068] (3) CuO nanoparticle modification of electrolyte interface: Using citric acid as a chelating agent and copper nitrate as a precursor, nano-sized CuO particles were prepared by combustion method, and pure phase CuO was obtained by calcination at 700℃. The obtained powder was ball-milled in a planetary ball mill for 2 hours, centrifuged in anhydrous ethanol for 5 minutes at 5000 rpm, and the supernatant was collected as CuO nanoparticle dispersion. The dispersion was dropped onto the surface of the half-cell obtained in step (2) using a microsyringe, dried, and then calcined at 900℃ for 1 hour.

[0069] (4) Preparation of porous air electrode: Same as step (4) in Example 5.

[0070] Comparative Example 1

[0071] The comparative method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides includes the following steps:

[0072] (1) Preparation of porous electrode support layer: Same as step (1) in Example 1.

[0073] (2) Dip-coating proton conductor electrolyte film: Same as step (2) in Example 1.

[0074] (3) Preparation of porous air electrode: An electrode slurry was prepared by mixing air electrode PBSCF with ethyl cellulose and terpineol at a mass ratio of 1:0.1:0.9. This slurry was then brushed onto the surface of the BZY electrolyte obtained in step (2), dried, and calcined at 950 degrees Celsius for 3 hours. A precursor solution was prepared by mixing the nitrate corresponding to PBC with citric acid, with a metal ion concentration of 0.5 mol / L. 1.6 μL / mm... 2 The precursor solution was added dropwise onto the PBSCF backbone, and the addition was repeated three times. After drying, the solution was calcined at 700 degrees Celsius for 2 hours.

[0075] The performance of the full cell was measured using hydrogen (3% H2O + 97% H2) as fuel and ambient air as the oxidant. Figures 2-3 As shown, based on the results of Examples 1-6 and Comparative Example 1, it can be seen that the performance of the full cell can be further improved by adjusting the dosage of the added metal oxide, modifying the interface with a mixture of multiple metal oxides, and optimizing the calcination temperature of the porous framework and active nanoelectrodes, as well as the electrolyte thickness.

[0076] This invention enhances the adhesion between the BZY electrolyte and the air electrode by simply introducing a low-melting-point metal oxide, thereby reducing interfacial contact resistance and comprehensively improving the overall performance of the battery. As a simple interfacial modification method, the strategy of introducing low-melting-point metal oxides also holds promise for solving interfacial contact problems in other solid oxide electrolytes.

[0077] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides, characterized in that, Includes the following steps: (1) A porous hydrogen electrode support layer was prepared by casting method and the organic matter was removed by pre-calcination at 800℃~1000℃ to obtain a porous electrode support layer. (2) The electrolyte powder is prepared into an electrolyte slurry and dipped onto the surface of the porous electrode support layer. The slurry is then calcined at 1450℃~1500℃ to form a solid oxide electrolyte film on the surface of the porous electrode support layer, thus obtaining a half cell. (3) The metal oxide precursor liquid is introduced into the surface of the solid oxide electrolyte film of the half cell and calcined at 850°C to 900°C to form a metal oxide modified electrolyte interface. (4) The air electrode powder is made into an electrode slurry and brushed onto the metal oxide modified electrolyte interface and calcined once at 900℃~950℃ to obtain a porous electrode framework. Then, the nitrate of the nano active electrode is made into a precursor liquid and repeatedly added to the porous electrode framework. The porous air electrode framework and nano active electrode composite structure are obtained by calcination at 700℃~800℃.

2. The method for improving the interfacial contact of solid oxide electrolytes using low-melting-point metal oxides according to claim 1, characterized in that, In step (1), the hydrogen electrode support layer comprises an electrolyte material BaZr with a mass ratio of (4-5):(5-6):

2. 0.85 Y 0.15 O 3-δ NiO and pore-forming agent spherical graphite.

3. The method for improving the interfacial contact of solid oxide electrolytes with low-melting-point metal oxides according to claim 1, characterized in that, In step (2), the solid content in the electrolyte slurry is 20wt% to 25wt%. The electrolyte slurry is a solution containing electrolyte powder and additives; The additives include butyl benzyl phthalate, triethanolamine, and polyethylene glycol butyral; The solvents in the electrolyte slurry are anhydrous ethanol and butanone; The pressure for dip coating can be either atmospheric pressure or negative pressure.

4. The method for improving the interfacial contact of solid oxide electrolytes with low-melting-point metal oxides according to claim 1, characterized in that, In step (3), the metal oxide in the metal oxide precursor solution includes CuO or (Y) 0.25 Bi 0.75 )2O3(YSB); The metal oxide precursor solution includes a nitrate solution of metal oxide or an ethanol dispersion of metal oxide nanoparticles. The concentration of metal ions in the metal oxide precursor solution is 0.05 mol / L to 0.2 mol / L; The introduction includes thermal droplet coating or thermal spraying.

5. The method for improving the interfacial contact of solid oxide electrolytes with low-melting-point metal oxides according to claim 1, characterized in that, In step (4), the air electrode is PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF); An electrode slurry was prepared by mixing an air electrode with ethyl cellulose and terpineol in a mass ratio of 1:(0.15-0.2):(0.8-0.85).

6. The method for improving the interfacial contact of solid oxide electrolytes with low-melting-point metal oxides according to claim 1, characterized in that, In step (4), the nano-active electrode is PrBaCo2O 5+δ (PBC); The precursor solution was prepared by mixing the nitrate of the nano-active electrode with citric acid, wherein the concentration of metal ions was 0.2 mol / L to 0.5 mol / L.

7. The method for improving the interfacial contact of solid oxide electrolytes with low-melting-point metal oxides according to claim 1, characterized in that, In step (2), the calcination time is 6h to 10h; In step (1), the preheating time is 2 to 3 hours; In step (3), the calcination time is 1h to 2h; In step (4), the first calcination time is 2h to 3h, and the second calcination time is 2h to 3h.

8. The method for improving the interfacial contact of solid oxide electrolytes with low-melting-point metal oxides according to claim 1, characterized in that, In step (2), the thickness of the solid oxide electrolyte film is 20 μm to 30 μm.

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