A solid oxide battery and its preparation method

Abstract

This invention relates to a solid oxide battery, comprising a full cell consisting of a half-cell, a reference electrode, and an oxygen electrode. The half-cell includes an electrolyte, and the reference electrode is a metal electrode located between the half-cell and the oxygen electrode. The reference electrode has a grid-like structure with a diameter of 5-20 mm, a grid size of 1-5 mm, a wire diameter of 0.02-0.2 mm, and a height of 0.02-0.2 mm. This invention also provides a method for preparing the aforementioned solid oxide battery. According to the solid oxide battery and its preparation method of this invention, the grid-like reference electrode enables uniform potential acquisition at the interface between the oxygen electrode and the electrolyte. Because the reference electrode has a small wire diameter and a large grid size, it does not affect the overall contact and electrochemical performance between the oxygen electrode and the electrolyte.

Description

Technical Field

[0001] This invention relates to solid oxide batteries, and more specifically to a solid oxide battery and a method for preparing the same. Background Technology

[0002] Solid oxide cells (SOCs) are a clean energy utilization technology that can directly convert the chemical energy of fuel into electrical energy or use electrical energy to synthesize small molecules such as hydrogen and carbon monoxide, showing considerable application potential. A solid oxide cell typically consists of three parts: a fuel electrode, an electrolyte, and an oxygen electrode. Oxygen production or oxygen reduction reactions usually occur on the oxygen electrode material, and the catalytic performance of the oxygen electrode is a crucial factor determining the overall performance of the battery. Due to high temperatures and airtightness requirements, research on solid oxide cells typically employs a four-electrode system to measure the fuel and oxygen electrodes. This only allows for the detection of the entire cell's performance, and the resulting polarization curves contain polarization information from both the fuel and oxygen electrodes, making it impossible to study the material composition of the oxygen electrode.

[0003] The introduction of a reference electrode is believed to allow for independent measurement of the oxygen electrode's voltage response, which helps eliminate interference from the fuel cell and electrolyte components and obtain intrinsic information about the oxygen electrode material. However, several issues exist regarding the placement of the reference electrode. There are generally three types of reference electrodes: planar annular (button) electrodes; Riso-type electrodes; and embedded reference electrodes. The most commonly used is the planar annular (button) electrode. Although the reference electrode is usually placed on the electrolyte surface outside the working electrode, the potential at the reference electrode is not the actual potential at the interface between the oxygen electrode and the electrolyte; it actually corresponds to the potential at a certain point in the middle of the electrolyte. Furthermore, this places high demands on the symmetry of the battery (especially for batteries with thicker electrolyte support). Even slight misalignments between the oxygen electrode and fuel electrode layers can significantly affect the electric field distribution within the electrolyte, thus impacting the repeatability of the reference electrode. While Riso-type electrodes can effectively address the problem of uneven electric field distribution within the electrolyte, their complex structure makes them difficult to use. Embedded reference electrodes, by adding a reference electrode layer between two electrolyte layers, collect the potential within the electrolyte. However, the potential collected is not the actual potential at the interface between the oxygen electrode and the electrolyte, and the manufacturing process is complex. Therefore, developing a reference electrode structure with high repeatability and simple fabrication is crucial. Summary of the Invention

[0004] To address the problems of SOC reference electrode testing technology in the prior art, this invention provides a solid oxide battery and its preparation method.

[0005] The solid oxide battery according to the present invention comprises a full cell consisting of a half cell, a reference electrode and an oxygen electrode, wherein the half cell includes an electrolyte, the reference electrode is a metal electrode located between the half cell and the oxygen electrode, and the reference electrode has a mesh structure with a diameter of 5-20 mm, a grid size of 1-5 mm, a wire diameter of 0.02-0.2 mm and a height of 0.02-0.2 mm.

[0006] Preferably, the distance deviation between the center of the oxygen electrode and the center of the reference electrode is 0-0.5 mm.

[0007] Preferably, the diameter of the oxygen electrode is 2-6 mm smaller than the diameter of the reference electrode.

[0008] Preferably, the half-cell is an electrolyte-supported half-cell or an anode-supported half-cell.

[0009] Preferably, the half-cell further includes a fuel electrode and a barrier layer, wherein the electrolyte is located between the fuel electrode and the barrier layer, and the barrier layer is located between the electrolyte and the reference electrode.

[0010] Preferably, the solid oxide battery further includes a fuel electrode current collector located on the fuel electrode and an oxygen electrode current collector located on the oxygen electrode.

[0011] Preferably, the solid oxide battery further includes wires connected to the fuel electrode, the reference electrode, and the oxygen electrode, respectively.

[0012] The method for preparing a solid oxide battery according to the present invention includes the following steps: S1, providing a half cell, and supporting a reference electrode on the surface of the half cell by screen printing; S2, preparing an oxygen electrode on the surface of the reference electrode by screen printing and spraying to provide a full cell; S3, subjecting the full cell to high-temperature sintering treatment.

[0013] Preferably, when the reference electrode is made of platinum or gold, the sintering temperature of step S3 is 900-1200℃; when the reference electrode is made of silver, the sintering temperature of step S3 is 900℃.

[0014] Preferably, the preparation method further includes the following steps: S4, printing current collectors on the surface of the full cell; S5, connecting wires.

[0015] According to the solid oxide battery and its preparation method of the present invention, a uniform potential acquisition at the interface between the oxygen electrode and the electrolyte can be achieved through a grid-like reference electrode. Because the reference electrode has a small wire diameter and a large grid size, it does not affect the overall contact and electrochemical performance between the oxygen electrode and the electrolyte. Furthermore, since the conductivity of the metal reference electrode is much higher than that of the oxygen electrode material and the electrolyte, and the reference electrode is thin, the current flowing through the reference electrode does not cause a significant voltage drop, thus exhibiting high measurement repeatability. Moreover, the reference electrode preparation method using screen printing is simple and can be easily combined with the oxygen electrode preparation process, completing battery preparation in a single sintering step. Therefore, the present invention provides a reference electrode structure with high repeatability and simple fabrication. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a solid oxide battery according to a preferred embodiment of the present invention.

[0017] Figure 2 yes Figure 1 A partial exploded view of the full battery.

[0018] Figure 3 yes Figure 2 A planar schematic diagram of the reference electrode.

[0019] Figure 4 Show Figure 1 Electrochemical testing results of solid oxide batteries.

[0020] Figure 5 This is a schematic diagram of the structure of a solid oxide battery according to another preferred embodiment of the present invention.

[0021] Figure 6 Show Figure 5 Electrochemical testing results of solid oxide batteries.

[0022] Figure 7 This is a schematic diagram of the structure of a solid oxide battery according to another preferred embodiment of the present invention.

[0023] Figure 8 Show Figure 7 Electrochemical testing results of solid oxide batteries. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, the raw materials used in the embodiments are all conventional raw materials, and the equipment used is all conventional equipment and commercially available products.

[0025] like Figure 1 , Figure 5 and Figure 7 As shown, the solid oxide battery according to the present invention includes a stacked fuel electrode current collector 1, a fuel electrode 2, an electrolyte 3, a barrier layer 4, a reference electrode 5, an oxygen electrode 6, and an oxygen electrode current collector 7, wherein the fuel electrode 2, the electrolyte 3, and the barrier layer 4 form a half-cell 9, and the half-cell 9, the reference electrode 5, and the oxygen electrode 6 form a full cell 10 (see...). Figure 2 The fuel electrode current collector 1 and the oxygen electrode current collector 7 are located on opposite sides of the full cell 10. The fuel electrode 2, the reference electrode 5 and the oxygen electrode 6 are respectively connected to wires 8 for electrochemical testing.

[0026] The method for preparing a solid oxide battery according to the present invention includes the following steps: S1, providing a fuel electrode 2 and a barrier layer 4 on opposite sides of an electrolyte 3 to provide a half-cell 9, and supporting a reference electrode 5 on the surface of the half-cell 9 by screen printing; S2, preparing an oxygen electrode 6 on the surface of the reference electrode 5 by screen printing and spraying to provide a full cell 10; S3, subjecting the full cell 10 to high-temperature sintering treatment; S4, printing current collectors on the surfaces of the fuel electrode 2 and the oxygen electrode 6 respectively to obtain a fuel electrode current collector 1 and an oxygen electrode current collector 7; S5, attaching wires 8 to the fuel electrode 2, the reference electrode 5, and the oxygen electrode 6 respectively.

[0027] The half-cell 9 of the solid oxide battery according to the present invention can be an electrolyte-supported half-cell, such as... Figure 1 and Figure 5 As shown, it can also be an anode-supported half-cell, such as... Figure 7 As shown.

[0028] The half-cell 9 of the solid oxide battery according to the present invention is a button cell with a diameter of 5-20 mm.

[0029] Fuel electrode 2 is a mixture of nickel oxide and electrolyte, with a thickness of 0.02-0.5 mm.

[0030] Electrolyte 3 is an oxygen ion conductor electrolyte, such as yttrium oxide stabilized zirconia solid electrolyte (YSZ) or scandium oxide stabilized zirconia solid electrolyte (SSZ), with a thickness of 0.01-1 mm.

[0031] The barrier layer 4 is a gadolinium-doped cerium oxide (GDC) layer with a thickness of 0.005-0.02 mm.

[0032] like Figure 2 As shown, the reference electrode 5 has a mesh structure with a diameter of 5-20 mm, a mesh size of 1-5 mm, a wire diameter of 0.02-0.2 mm, and a height of 0.02-0.2 mm. In a preferred embodiment, as... Figure 3As shown, the reference electrode 5 is a mesh structure with a radius of 8.5 mm, a mesh size of 3 mm, and a wire diameter of 0.05 mm. The results indicate that by printing a mesh-like reference electrode 5 at the interface between the half-cell 9 and the oxygen electrode 6, uniform potential acquisition at the interface between the oxygen electrode 6 and the electrolyte 3 can be achieved.

[0033] The reference electrode 5 is made of platinum, gold, or silver. When the reference electrode 5 is made of platinum or gold, the sintering temperature of step S3 in the method for preparing a solid oxide battery according to the present invention is 900-1200°C. When the reference electrode 5 is made of silver, the sintering temperature of step S3 in the method for preparing a solid oxide battery according to the present invention is 900°C.

[0034] The centers of oxygen electrode 6 and reference electrode 5 can be aligned, such as... Figure 1 and Figure 7 As shown, they can also be misaligned, such as... Figure 5 As shown. Preferably, the distance deviation between the center of the oxygen electrode 6 and the center of the reference electrode 5 is 0-0.5 mm.

[0035] The diameter of the oxygen electrode 6 is 2-6 mm smaller than that of the reference electrode 5, thereby ensuring better electric field symmetry and reserving space for the wiring of the reference electrode 5.

[0036] The oxygen electrode 6 is made of a material that has oxygen ion conductivity, such as perovskite or fluorite.

[0037] Current collectors 1 and 7 are made of platinum, gold, or silver with a porous structure and a thickness of 0.005-0.02 μm.

[0038] The wire 8 is bonded to the electrode by high-temperature curing of silver paste and fixed by high-temperature ceramic adhesive.

[0039] Example 1: Performance testing of the LSCF oxygen electrode in an electrolyte-supported battery under a reference electrode.

[0040] The battery structure in this example is LSCF|Pt(reference)|GDC|SSZ|NiO-YSZ.

[0041] A 20mm diameter SSZ electrolyte sheet was screen-printed with GDC barrier layer paste and NiO-YSZ fuel electrode paste on both sides, respectively. The resulting half-cell GDC|SSZ|NiO-YSZ was sintered at 1200℃ for 5 hours. A reference electrode was printed on the GDC side using platinum paste and dried at 200℃, resulting in an electrode layer with an outer diameter of 17mm, a wire diameter of 0.05μm, and a mesh size of 3mm*3mm. LSCF powder was ball-milled with a 6% ethyl cellulose terpineol solution for 2 hours, and the resulting paste was screen-printed onto the surface of the reference electrode. The oxygen electrode had a diameter of 15mm. The resulting cell was heated at 1℃ / min and held at 1000℃ for 2 hours to obtain a full cell. Silver paste was uniformly coated onto the surfaces of the fuel electrode and oxygen electrode and dried at 200℃ for 2 hours. Silver wires were then connected to the oxygen electrode, reference electrode, and fuel electrode using silver paste, cured at 200℃, and the nodes were reinforced with high-temperature ceramic adhesive at 250℃. Three parallel cell samples were prepared according to the above steps, and IV electrochemical tests were performed on the three coin cells at 750°C.

[0042] The structure of the obtained LSCF|Pt(reference)|GDC|SSZ|NiO-YSZ is as follows Figure 1 As shown; electrochemical performance diagram as shown Figure 4 As shown, the three parallel cells exhibit good consistency, indicating that the test results using this reference electrode are easily reproducible.

[0043] Example 2: Performance testing of a misprinted LSCF oxygen electrode in an electrolyte-supported battery under a reference electrode.

[0044] In this embodiment, the electrode preparation method is the same as in Example 1, except for the following differences. When screen printing the LSCF electrode, the center of the electrode is offset from the center of the half-cell by 0.2 mm.

[0045] A schematic diagram of the structure of LSCF|Pt(reference)|GDC|SSZ|NiO-YSZ with oxygen electrode misalignment is shown below. Figure 5 As shown; electrochemical performance diagram as shown Figure 6 As shown, the electrochemical data of the misaligned oxygen electrode cell are basically consistent with those in Example 1, indicating that the use of this reference electrode does not require strict center alignment between the oxygen electrode and the half-cell, and has good reliability.

[0046] Example 3: Performance testing of the LSCF oxygen electrode in an anode-supported cell under a reference electrode.

[0047] The battery structure in this example is LSCF|Ag(reference)|GDC|YSZ|NiO-YSZ.

[0048] Green materials of GDC|YSZ|NiO-YSZ were prepared using a co-casting method. The green materials were cut into button cell shapes and sintered at 1400℃ for 5 hours to obtain GDC|YSZ|NiO-YSZ button half-cells with a diameter of 20 mm. A reference electrode layer was printed on the GDC side using silver paste and dried at 200℃. The resulting electrode layer had an outer diameter of 17 mm, a wire diameter of 0.05 μm, and a mesh size of 3 mm x 3 mm. LSCF powder was ball-milled with a 6% ethyl cellulose solution in terpineol for 2 hours, and the resulting paste was screen-printed onto the surface of the reference electrode. The oxygen electrode had a diameter of 15 mm. The resulting cell was heated at 900℃ for 2 hours with a rate of 1℃ / min to obtain a half-cell. Silver paste was uniformly coated onto the surfaces of the fuel electrode and oxygen electrode and dried at 200℃ for 2 hours. Subsequently, silver wires were connected to the oxygen electrode, reference electrode, and fuel electrode using silver paste and cured at 200°C. The nodes were then reinforced with high-temperature ceramic adhesive at 250°C, and the button cell was subjected to IV electrochemical testing at 750°C.

[0049] The obtained LSCF|Ag(reference)|GDC|YSZ|NiO-YSZ structure is as follows Figure 7 As shown; electrochemical performance is as follows Figure 8 As shown, the electrochemical data of the anode-supported battery is basically consistent with the electrochemical data of the electrolyte-supported battery in Example 1, indicating that the reference electrode can work normally in both electrolyte-supported and anode-supported batteries. The difference in electrolyte layer thickness does not affect the data quality, and the data between them have a certain degree of reference and good repeatability.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A solid oxide battery, characterized in that, The solid oxide battery includes a full cell consisting of a half cell, a reference electrode, and an oxygen electrode. The half cell includes an electrolyte. The reference electrode is a metal electrode located between the half cell and the oxygen electrode. The reference electrode has a grid-like structure with a diameter of 5-20 mm, a grid size of 1-5 mm, a wire diameter of 0.02-0.2 mm, and a height of 0.02-0.2 mm.

2. The solid oxide battery according to claim 1, characterized in that, The distance deviation between the center of the oxygen electrode and the center of the reference electrode is 0-0.5 mm.

3. The solid oxide battery according to claim 1, characterized in that, The diameter of the oxygen electrode is 2-6 mm smaller than that of the reference electrode.

4. The solid oxide battery according to claim 1, characterized in that, The half-cell is either an electrolyte-supported half-cell or an anode-supported half-cell.

5. The solid oxide battery according to claim 1, characterized in that, The half-cell also includes a fuel electrode and a barrier layer, wherein the electrolyte is located between the fuel electrode and the barrier layer, and the barrier layer is located between the electrolyte and the reference electrode.

6. The solid oxide battery according to claim 5, characterized in that, The solid oxide battery also includes a fuel electrode current collector located on the fuel electrode and an oxygen electrode current collector located on the oxygen electrode.

7. The solid oxide battery according to claim 5, characterized in that, The solid oxide battery also includes wires that are connected to the fuel electrode, reference electrode, and oxygen electrode, respectively.

8. A method for preparing a solid oxide battery according to any one of claims 1-7, characterized in that, The preparation method includes the following steps: S1 provides a half-cell, on which a reference electrode is supported by screen printing on the surface of the half-cell; S2, an oxygen electrode is prepared on the surface of a reference electrode by screen printing and spraying to provide a full cell; S3 involves high-temperature sintering of the entire battery.

9. The preparation method according to claim 8, characterized in that, When the reference electrode is made of platinum or gold, the sintering temperature in step S3 is 900-1200℃; when the reference electrode is made of silver, the sintering temperature in step S3 is 900℃.

10. The preparation method according to claim 8, characterized in that, The preparation method also includes the following steps: S4, printing current collectors on the surface of the full cell; S5, connecting wires.

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