An in-situ activation method for improving the hydrogen production performance of solid oxide electrolysis cells

Abstract

The present invention belongs to the field of solid oxide electrolytic cells and relates to an in-situ activation method for improving the hydrogen production performance of solid oxide electrolytic cells. The membrane electrode of the solid oxide electrolytic cell includes a hydrogen electrode, an electrolyte, and an oxygen electrode. The in-situ activation method includes applying a voltage of 1 to 2V to the cell, passing an activation gas of hydrogen or a mixture of hydrogen and nitrogen to the hydrogen electrode, and passing an activation gas of air or oxygen to the oxygen electrode. The activation temperature is 600 to 1000°C, and the activation humidity is 3%-80%. The oxygen electrode is a material containing a cobalt-containing perovskite oxide and an electrolyte composite. The method of the present invention can directly improve the electrochemical performance of the cell in a solid oxide electrolysis hydrogen production test device by regulating the activation voltage, the type of gas during the activation process, the activation temperature, and the activation humidity.

Description

Technical Field

[0001] The present invention belongs to the field of solid oxide electrolysis cells, and in particular relates to an in-situ activation method for improving the hydrogen production performance of solid oxide electrolysis cells. Background Art

[0002] The development and progress of society cannot be separated from the support and supply of energy. Traditional fossil energy is facing resource depletion and causes great pollution to the environment. In order to solve the above problems, the development of renewable energy, especially hydrogen energy, is particularly important, because hydrogen has the advantages of being clean, storable, and having high elemental abundance, and has broad development prospects. Water electrolysis hydrogen production technology can produce large-scale green hydrogen, among which solid oxide electrolysis cells (SOECs) have the advantages of being clean, efficient, energy-saving, and environmentally friendly. The required electricity can come from intermittent renewable energy sources such as wind power and solar energy, and the heat can come from waste heat from factories. This technology can effectively combine electricity and heat energy and has received widespread attention.

[0003] The performance of SOECs is primarily affected by the performance of the membrane electrode, with the slow anodic oxygen evolution reaction being the primary limiting factor. To improve the performance of solid oxide electrolysis for hydrogen production, methods such as impregnation can yield an active interface with smaller particle sizes for the preparation of high-performance oxygen electrodes. Impregnation methods typically require repeated impregnation and calcination to achieve an impregnation level in the electrode that can impact performance. These methods are complex, time-consuming, and material-intensive, making them prohibitive for large-scale commercial use. Summary of the Invention

[0004] The present invention proposes an in-situ activation technology for improving the hydrogen production performance of solid oxide electrolysis cells. Compared with cells that do not use in-situ activation technology, cells using the activation technology of the present invention have higher electrochemical performance and thus higher hydrogen production performance.

[0005] The technical solutions of the present invention are as follows:

[0006] The present invention provides an in-situ activation method for improving the hydrogen production performance of a solid oxide electrolytic cell. The membrane electrode of the solid oxide electrolytic cell includes a hydrogen electrode, an electrolyte, and an oxygen electrode. The in-situ activation method includes applying a voltage of 1 to 2 V to the cell, introducing an activation gas, hydrogen or a mixture of hydrogen and nitrogen, into the hydrogen electrode, and introducing an activation gas, air or oxygen, into the oxygen electrode. The activation temperature is 600 to 1000° C., and the activation humidity is 3% to 80%. The oxygen electrode is a composite material containing a cobalt-containing perovskite oxide and an electrolyte.

[0007] In the above technical solution, further, the hydrogen electrode is Ni-YSZ, Ni-GDC or Ni-LSGM; and the electrolyte is YSZ, GDC, SDC or LSGM.

[0008] In the above technical solution, further, the activation humidity is 30%-60%.

[0009] In the above technical solution, further, in the hydrogen and nitrogen mixed gas, the volume ratio of hydrogen to nitrogen is: (1:0)-(1:10).

[0010] In the above technical solution, further, the activation method comprises the following steps:

[0011] (1) Heating the battery to 600-1000°C;

[0012] (2) introducing activated gas into the hydrogen electrode side and the oxygen electrode side respectively;

[0013] (3) The hydrogen electrode side is connected to a water vapor generator, and the water bath temperature is 20-95°C;

[0014] (4) Apply a voltage of 0.5-2V to the battery for activation, and the activation time is 1-12 hours.

[0015] In the above technical solution, further, in the step (1), nitrogen or helium is first introduced into the hydrogen electrode side for purging, and then the temperature is increased at a heating rate of 5°C / min-15°C / min.

[0016] In the above technical solution, further, the flow rate of the nitrogen or helium purge in step (1) is 20-80 sccm.

[0017] In the above technical solution, further, the flow rate of the activation gas introduced in step (2) is 50-150 sccm.

[0018] In the above technical solution, further, in step (3), the water bath temperature is 60-85°C.

[0019] In the above technical solution, further, the method for preparing the battery includes the following steps:

[0020] (1) preparing a hydrogen electrode-supported half-electrolytic cell sheet by tape casting, calendering, or powder dry pressing, wherein the hydrogen electrode support layer is made of Ni-YSZ, Ni-GDC, or Ni-LSGM, and the electrolyte is YSZ, GDC, SDC, or LSGM;

[0021] (2) preparing oxygen electrode powder by combustion method, solid phase synthesis method or chemical precipitation method, wherein the oxygen electrode material is SSC-SDC, LSM-YSZ or BSCF-GDC;

[0022] (3) The oxygen electrode powder and the binder are mixed in a mass ratio of 10:1 to 2:1 to prepare an oxygen electrode slurry, which is then coated on the half-cell sheet supported by the hydrogen electrode and calcined at 700-1200°C for 1-10 hours.

[0023] In the above technical solution, further, the binder is 6%wt ethyl cellulose in terpineol.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention utilizes in-situ activation technology during solid oxide electrolysis hydrogen production full cell testing to simply and effectively improve the electrolytic performance of the electrolytic cell. By applying a suitable activation voltage to the cell, the oxygen electrode and electrolyte are more tightly bonded under the drive of the electric field. In addition, the appropriate activation voltage also activates the reaction sites at the oxygen electrode and the interface, thereby improving the electrochemical performance of the cell.

[0026] (2) Compared with conventional batteries without voltage activation, the batteries tested using in-situ voltage activation technology in the present invention have significantly higher hydrogen production performance.

[0027] (3) The present invention improves the hydrogen production capacity of the electrolytic cell through online in-situ activation technology. This method is simple, effective, low-cost, and has practical application and promotion value.

[0028] (4) The present invention is applicable to a system for producing hydrogen by electrolyzing water using activated high-temperature oxygen ion-conducting solid oxides. The battery composition range is as follows: the hydrogen electrode is Ni-YSZ, Ni-GDC or Ni-LSGM, etc.; the electrolyte is YSZ, GDC, SDC or LSGM, etc.; the oxygen electrode is a composite material of a perovskite-type substance containing Co or (and) Sr elements and an electrolyte. This type of oxygen electrode is relatively active and is prone to interfacial side reactions with the electrolyte. The use of this in-situ activation method can simply and effectively improve the performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Comparison of current density-voltage curves of cell-1, cell-2, cell-3, and cell-4;

[0030] Figure 2 Hydrogen production curves of cell-1, cell-2, cell-3, and cell-4;

[0031] Figure 3 Comparison of current density-voltage curves of cell-a and cell-b;

[0032] Figure 4 Hydrogen production curves of cell-a and cell-b;

[0033] Figure 5 Comparison of current density-voltage curves of cell-4, cell-5, cell-6, and cell-7;

[0034] Figure 6 Hydrogen production curves of cell-4, cell-5, cell-6, and cell-7;

[0035] Figure 7 Graph showing the relationship between water bath temperature and humidity. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0037] The corresponding relationship between the water bath temperature and the battery humidity in the following examples is as follows: Figure 7 As shown, a specific water bath temperature corresponds to a saturated vapor pressure of water, which can be found through the saturated vapor pressure table of water. Then the ratio of the saturated vapor pressure of water to the atmospheric pressure is the absolute humidity of water, which is recorded as the battery humidity at this time. Figure 7 The results show that temperature and battery humidity are in a corresponding relationship. Therefore, the required battery humidity can be adjusted by controlling the temperature during the activation process. In the following examples and comparative examples, the range of δ is 0≤δ≤0.1, and the binder used is 6%wt ethyl cellulose in terpineol.

[0038] Comparative Example 1:

[0039] The performance test of cell-1 without in-situ activation technology is as follows:

[0040] (1) Preparation of battery cells

[0041] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. The slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired battery (denoted as cell-1).

[0042] (2) SOEC test

[0043] Install cell-1 in a solid oxide electrolysis hydrogen production test device, introduce nitrogen gas as a purge to the hydrogen electrode side with a gas flow rate of 30 sccm, and then raise the device temperature to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode. Finally, directly connect the electrochemical performance test device to perform the electrochemical performance test of cell-1, such as Figure 1-4 shown.

[0044] Figure 1 The current density-voltage curve of cell-1 is shown. At an electrolysis voltage of 1.3 V, the electrolysis current density of cell-1 is 0.4503 A / cm 2 . Figure 2 The relationship between the hydrogen production performance of cell-1 and the electrolysis voltage is shown. At an electrolysis voltage of 1.3 V, the hydrogen production of cell-1 is 188.2 mL cm -2 h -1 .

[0045] Comparative Example 2:

[0046] The performance test of activated battery cell-2 was conducted at 800°C, 0.3V, 50% humidity, hydrogen on the hydrogen electrode side, and air on the oxygen electrode side. The steps are as follows:

[0047] (1) Preparation of battery cells

[0048] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. The slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired cell (denoted as cell-2).

[0049] (2) SOEC test

[0050] Install cell-2 in a solid oxide electrolysis hydrogen production test device, introduce nitrogen into the hydrogen electrode side as a purge, with a gas flow rate of 30 sccm, and then raise the temperature of the device to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, first switch the gas to the hydrogen electrode side to hydrogen, and introduce air into the oxygen electrode side, with a gas flow rate of 100 sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode. Connect both ends of the battery to a power control device that can activate the battery. Set the activation voltage to 0.3V and the activation time to 4h. After the activation is completed, the electrochemical performance of cell-2 is tested, such as Figure 1-2 shown.

[0051] Figure 1 The current density-voltage curve of cell-2 is shown. At an electrolysis voltage of 1.3 V, the electrolysis current density of cell-2 is 0.3717 A / cm 2 . Figure 2 The curve showing the relationship between the hydrogen production performance of cell-2 and the electrolysis voltage shows that at an electrolysis voltage of 1.3 V, the hydrogen production of cell-2 is 155.3 mL cm -2 h -1 .

[0052] Comparative Example 3:

[0053] The performance test of the cell-3 battery activated at 800°C, 1.3V, 50% humidity, nitrogen on the hydrogen electrode side and helium on the oxygen electrode side is as follows:

[0054] (1) Preparation of battery cells

[0055] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. The slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired cell (denoted as cell-3).

[0056] (2) SOEC test

[0057] Install cell-3 in a solid oxide electrolysis hydrogen production test device, introduce nitrogen into the hydrogen electrode side as a purge, with a gas flow rate of 30 sccm, and then raise the temperature of the device to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, continue to introduce nitrogen into the hydrogen electrode side and helium into the oxygen electrode side, with a gas flow rate of 100 sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode. Connect both ends of the battery to a power control device that can activate the battery. Set the activation voltage to 1.3V and the activation time to 4h. After the activation is completed, the electrochemical performance of cell-3 is tested, such as Figure 1-2 shown.

[0058] Figure 1 The current density-voltage curve of cell-3 is shown. At an electrolysis voltage of 1.3V, the electrolysis current density of cell-3 is 0.4227A / cm 2 . Figure 2 The curve showing the relationship between the hydrogen production performance of cell-3 and the electrolysis voltage shows that at an electrolysis voltage of 1.3 V, the hydrogen production of cell-3 is 183.3 mL cm -2 h -1 .

[0059] Comparative Example 4:

[0060] The performance comparison of Ni-YSZ|YSZ|GDC|PCF64 batteries using activation technology and direct testing is as follows:

[0061] (1) Preparation of battery cells

[0062] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, where the cathode support layer was made of Ni-YSZ and the electrolyte was YSZ; a GDC interlayer was added to the YSZ surface using magnetron sputtering technology. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Pr 0.6 Ca 0.4 FeO 3-δ (PCF64). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. The slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired cells (denoted as cell-a and cell-b).

[0063] (2) SOEC test

[0064] Cell-a:

[0065] Install cell-a in a solid oxide electrolysis hydrogen production test device, introduce nitrogen gas into the hydrogen electrode side as a purge, with a gas flow rate of 30 sccm, and then raise the device temperature to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode. Finally, directly connect the electrochemical performance test device to perform the electrochemical performance test of cell-a, such as Figure 3-4 shown.

[0066] Cell-b:

[0067] Install cell-b in a solid oxide electrolysis hydrogen production test device, introduce nitrogen into the hydrogen electrode side as a purge, with a gas flow rate of 30 sccm, and then raise the temperature of the device to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, switch the gas introduced into the hydrogen electrode side to hydrogen, and introduce air into the oxygen electrode side, with a gas flow rate of 100 sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode. Connect both ends of the battery to a power control device that can activate the battery. Set the activation voltage to 1.3V and the activation time to 4h. After the activation is completed, the electrochemical performance of cell-b is tested, such as Figure 3-4 shown.

[0068] Figure 3 The current density-voltage curves of cell-a and cell-b are shown. At an electrolysis voltage of 1.3 V, the electrolysis current density of cell-a is 0.1951 A / cm 2 , the electrolysis current density of cell-b is 0.1953A / cm 2 . Figure 2 The relationship between the hydrogen production performance of cell-a and cell-b and the electrolysis voltage is shown. At an electrolysis voltage of 1.3 V, the hydrogen production of cell-a is 81.5 mL cm -2 h -1 , the hydrogen production of cell-b is 81.6 mL cm -2 h -1 From this, it can be seen that the activation effect of in-situ activation technology is basically negligible when the oxygen electrode is a perovskite material that does not contain Co or (and) Sr elements.

[0069] Example 1:

[0070] The performance test of the activated battery cell-4 was conducted at 700°C, 1.3V, 50% humidity, hydrogen on the hydrogen electrode side, and air on the oxygen electrode side. The steps are as follows:

[0071] (1) Preparation of battery cells

[0072] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. This slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired battery (denoted as cell-4).

[0073] (2) SOEC test

[0074] Install cell-4 in a solid oxide electrolysis hydrogen production test device, introduce nitrogen gas into the hydrogen electrode side as a purge, with a gas flow rate of 30 sccm, and then raise the temperature of the device to 700°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, first switch the gas to the hydrogen electrode side to hydrogen, and introduce air into the oxygen electrode side, with a gas flow rate of 100 sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode (50% humidity). Connect the two ends of the battery to a power control device to apply a constant voltage to both ends of the battery. The device can charge and discharge the battery to apply voltage to the battery to activate the battery. Set the activation voltage to 1.3V and the activation time to 4h. After the activation is completed, raise the temperature of the device to 800°C at a heating rate of 5°C / min, and then test the electrochemical performance of cell-4, such as Figure 1-2 shown.

[0075] Figure 1 The current density-voltage curve of cell-4 is shown. At an electrolysis voltage of 1.3V, the electrolysis current density of cell-4 is 0.4959A / cm 2 . Figure 2 The curve showing the relationship between the hydrogen production performance of cell-4 and the electrolysis voltage shows that at an electrolysis voltage of 1.3 V, the hydrogen production of cell-4 is 207.25 mL cm -2 h -1 .

[0076] Example 2

[0077] The performance test of the activated battery cell-5 was conducted at 800°C, 1.3V, 50% humidity, hydrogen on the hydrogen electrode side, and air on the oxygen electrode side. The steps are as follows:

[0078] (1) Preparation of battery cells

[0079] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. The slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired cell (denoted as cell-5).

[0080] (2) SOEC test

[0081] Install cell-5 in a solid oxide electrolysis hydrogen production test device, introduce nitrogen into the hydrogen electrode side as a purge, with a gas flow rate of 30sccm, and then raise the temperature of the device to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, switch the gas introduced into the hydrogen electrode side to hydrogen, and introduce air into the oxygen electrode side, with a gas flow rate of 100sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode (50% humidity). Connect both ends of the battery to a power control device that can activate the battery. Set the activation voltage to 1.3V and the activation time to 4h. After the activation is completed, the electrochemical performance of cell-5 is tested, such as Figure 5-6 shown.

[0082] Figure 5 The current density-voltage curve of cell-5 is shown. At an electrolysis voltage of 1.3V, the electrolysis current density of cell-5 is 0.6298A / cm 2 . Figure 6 The relationship between the hydrogen production performance of cell-5 and the electrolysis voltage is shown. At an electrolysis voltage of 1.3 V, the hydrogen production of cell-5 is 263.2 mL cm -2 h -1 .

[0083] Example 3

[0084] The performance test of the activated cell-6 battery was conducted at 800°C, 1.5V, 30% humidity, with hydrogen and nitrogen (volume ratio of 9:1) on the hydrogen electrode side and air on the oxygen electrode side. The steps are as follows:

[0085] (1) Preparation of battery cells

[0086] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. This was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired battery (denoted as cell-6).

[0087] (2) SOEC test

[0088] Install cell-6 in a solid oxide electrolysis hydrogen production test device, introduce nitrogen into the hydrogen electrode side as a purge, with a gas flow rate of 30sccm, and then raise the temperature of the device to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, switch the gas introduced into the hydrogen electrode side to 90% hydrogen and 10% nitrogen, and introduce air into the oxygen electrode side, with a gas flow rate of 100sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 70°C to control the water vapor content entering the hydrogen electrode (30% humidity). Connect both ends of the battery to a power control device that can activate the battery. Set the activation voltage to 1.5V and the activation time to 4h. After the activation is completed, set the water bath temperature of the water vapor generator to 80°C, and after stabilization, conduct the electrochemical performance test of cell-6, such as Figure 5-6 shown.

[0089] Figure 5 The current density-voltage curve of cell-6 is shown. At an electrolysis voltage of 1.3V, the electrolysis current density of cell-6 is 0.6198A / cm 2 . Figure 6 The curve showing the relationship between the hydrogen production performance of cell-6 and the electrolysis voltage shows that at an electrolysis voltage of 1.3 V, the hydrogen production of cell-6 is 259.0 mL cm -2 h -1 .

[0090] Example 4

[0091] The performance test of the activated battery cell-7 was conducted at 800°C, 1.3V, 50% humidity, with hydrogen flowing through the hydrogen electrode side and oxygen flowing through the oxygen electrode side. The steps are as follows:

[0092] (1) Preparation of battery cells

[0093] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. The slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired cell (denoted as cell-7).

[0094] (2) SOEC test

[0095] Install cell-7 in a solid oxide electrolysis hydrogen production test device, introduce nitrogen into the hydrogen electrode side as a purge, with a gas flow rate of 30 sccm, and then raise the temperature of the device to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, continue to introduce hydrogen into the hydrogen electrode side and oxygen into the oxygen electrode side, with a gas flow rate of 100 sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode (50% humidity). Connect both ends of the battery to a power control device that can activate the battery. Set the activation voltage to 1.3V and the activation time to 4h. After the activation is completed, set the water bath temperature of the water vapor generator to 80°C, and after stabilization, conduct the electrochemical performance test of cell-7, such as Figure 5-6 shown.

[0096] Figure 5 The current density-voltage curve of cell-7 is shown. At an electrolysis voltage of 1.3V, the electrolysis current density of cell-7 is 0.7525A / cm 2 . Figure 6 The curve showing the relationship between the hydrogen production performance of cell-7 and the electrolysis voltage shows that at an electrolysis voltage of 1.3 V, the hydrogen production of cell-7 is 314.5 mL cm -2 h -1 .

[0097] Example 5

[0098] The performance test of the activated cell-8 battery was conducted at 800°C, 1.5V, 30% humidity, with hydrogen and nitrogen (volume ratio of 1:9) on the hydrogen electrode side and air on the oxygen electrode side. The steps are as follows:

[0099] (1) Preparation of battery cells

[0100] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. This slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired battery (denoted as cell-8).

[0101] (2) SOEC test

[0102] The cell-8 was installed in a solid oxide electrolysis hydrogen production test device, and nitrogen was introduced into the hydrogen electrode side as a purge with a gas flow rate of 30 sccm. The temperature of the device was then raised to 800°C at a heating rate of 5°C / min. After the test device was heated to the specified temperature, the gas introduced into the hydrogen electrode side was switched to 90% nitrogen and 10% hydrogen, and air was introduced into the oxygen electrode side, with a gas flow rate of 100 sccm. The heating switch of the water vapor generator connected to the hydrogen electrode side was turned on, and the water bath temperature was set to 70°C to control the water vapor content entering the hydrogen electrode (30% humidity). The two ends of the battery were connected to a power control device that can activate the battery. The activation voltage was set to 1.5V and the activation time was set to 4h. After activation, the water bath temperature of the water vapor generator was set to 80°C. After stabilization, the electrochemical performance of the cell-8 was tested.

[0103] The electrolysis current density and hydrogen production of cell-8 at an electrolysis voltage of 1.3 V are listed in Table 1. At an electrolysis voltage of 1.3 V, the electrolysis current density of cell-8 is 0.4701 A / cm 2 , the hydrogen production was 196.5 mL cm -2 h -1 .

[0104] Example 6

[0105] The performance test of the activated battery cell-9 was conducted at 800°C, 1.3V, 30% humidity, hydrogen on the hydrogen electrode side, and air on the oxygen electrode side. The steps are as follows:

[0106] (1) Preparation of battery cells

[0107] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. The slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired battery (denoted as cell-9).

[0108] (2) SOEC test

[0109] The cell-9 was installed in a solid oxide electrolysis hydrogen production test device, and nitrogen was introduced into the hydrogen electrode side as a purge with a gas flow rate of 30 sccm. Then the temperature of the device was raised to 800°C at a heating rate of 5°C / min. After the test device was heated to the specified temperature, the gas introduced into the hydrogen electrode side was switched to hydrogen, and air was introduced into the oxygen electrode side, with a gas flow rate of 100 sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 70°C to control the water vapor content entering the hydrogen electrode (30% humidity). The two ends of the battery were connected to a power control device that can activate the battery. Set the activation voltage to 1.3V and the activation time to 4h. After the activation is completed, the electrochemical performance of the cell-9 was tested.

[0110] The electrolysis current density and hydrogen production of cell-9 at an electrolysis voltage of 1.3 V are listed in Table 1. At an electrolysis voltage of 1.3 V, the electrolysis current density of cell-9 is 0.5278 A / cm 2 , the hydrogen production was 220.6 mL cm -2 h -1 .

[0111] Example 7

[0112] The performance test of the activated battery cell-10 was conducted at 800°C, 1.5V, 50% humidity, hydrogen on the hydrogen electrode side, and air on the oxygen electrode side. The steps are as follows:

[0113] (1) Preparation of battery cells

[0114] The cathode-supported half-electrolytic cell sheet was prepared by tape casting technology, wherein the cathode support layer material was Ni-YSZ and the electrolyte was YSZ. The oxygen electrode powder was prepared by combustion method, and the oxygen electrode material was Sm 0.5 Sr 0.5 CoO 3+δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC). The oxygen electrode powder and binder were mixed in a mass ratio of 10:3 to prepare an oxygen electrode slurry. The slurry was then coated onto a cathode-supported half-cell and calcined at 900°C for 2 hours to obtain the desired cell (denoted as cell-10).

[0115] (2) SOEC test

[0116] Install cell-10 in a solid oxide electrolysis hydrogen production test device, introduce nitrogen into the hydrogen electrode side as a purge, with a gas flow rate of 30sccm, and then raise the temperature of the device to 800°C at a heating rate of 5°C / min. After the test device is heated to the specified temperature, switch the gas introduced into the hydrogen electrode side to hydrogen, and introduce air into the oxygen electrode side, with a gas flow rate of 100sccm. Turn on the heating switch of the water vapor generator connected to the hydrogen electrode side, and set the water bath temperature to 80°C to control the water vapor content entering the hydrogen electrode (50% humidity). Connect both ends of the battery to a power control device that can activate the battery. Set the activation voltage to 1.5V and the activation time to 4h. After activation is completed, the electrochemical performance of cell-10 is tested.

[0117] The electrolysis current density and hydrogen production of cell-10 at an electrolysis voltage of 1.3 V are listed in Table 1. At an electrolysis voltage of 1.3 V, the electrolysis current density of cell-10 is 0.6872 A / cm 2 , the hydrogen production was 287.2 mL cm -2 h -1 .

[0118] It can be seen from the comparative examples and the examples that the activation effect of the in-situ activation technology on the solid oxide electrolytic cell is related to the material properties of the battery, the activation voltage, the type of gas during the activation process, the activation temperature and the activation humidity. It can be seen from comparative examples 1, 2, and 3 that inappropriate activation parameters will not only not improve the electrochemical performance of the electrolytic cell, but may even cause the battery to decay. It can be seen from comparative example 4 that the activation effect of the in-situ activation technology is basically negligible when the oxygen electrode is a perovskite-like material that does not contain Co or (and) Sr elements. It can be seen from comparative example 1 and Example 1 that the in-situ activation technology of the present invention can significantly improve the electrochemical performance of the battery, and the electrolysis current density and hydrogen production of the battery are significantly increased. It can be seen from Examples 1-7 that the activation temperature, activation voltage, activation humidity, and activation gas type will affect the final activation effect of the battery to varying degrees. By adjusting the appropriate activation parameters, the battery performance can be significantly improved. The activation voltage can provide an electric field during the activation process, and the battery makes the oxygen electrode and the electrolyte more tightly combined under the drive of the electric field force. In addition, the gas atmosphere, activation temperature and activation humidity during the activation process also significantly affect the final activation effect. These parameters mainly affect the reaction sites of the oxygen electrode and the interface, thereby affecting the electrochemical performance of the battery after activation.

[0119] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

[0120] Table 1 Comparison of battery performance activated under different conditions

[0121]

[0122]

Claims

1. An in-situ activation method for improving the hydrogen production performance of a solid oxide electrolytic cell, wherein the membrane electrode of the solid oxide electrolytic cell comprises a hydrogen electrode, an electrolyte and an oxygen electrode, characterized in that: The in-situ activation method includes applying a voltage of 1 to 2 V to the electrolytic cell, introducing hydrogen or a mixture of hydrogen and nitrogen into the hydrogen electrode, and introducing air or oxygen into the oxygen electrode. The activation temperature is 600 to 1000°C, and the activation humidity is 3% to 80%. The oxygen electrode is a composite material containing a cobalt-containing perovskite oxide and an electrolyte.

2. The in-situ activation method according to claim 1, wherein The hydrogen electrode is Ni-YSZ, Ni-GDC or Ni-LSGM; the electrolyte is YSZ, GDC, SDC or LSGM.

3. The in-situ activation method according to claim 1, wherein The activation humidity is 30% to 60%.

4. The in-situ activation method according to claim 1, wherein In the hydrogen and nitrogen mixed gas, the volume ratio of hydrogen to nitrogen is: (1:0)~(1:10).

5. The in-situ activation method according to claim 1, characterized in that The following steps are involved: (1) Raise the temperature of the electrolytic cell to 600~1000℃; (2) Activated gas is introduced into the hydrogen electrode side and the oxygen electrode side respectively; (3) The hydrogen electrode side is connected to a water vapor generator, and the water bath temperature is 20~95℃; (4) Apply a voltage of 1 to 2 V to the electrolytic cell for activation for 1 to 12 hours.

6. The in-situ activation method according to claim 5, characterized in that In the step (1), nitrogen or helium is first introduced into the hydrogen electrode side for purging, and then the temperature is increased at a heating rate of 5°C / min to 15°C / min; the flow rate of the purging nitrogen or helium is 20 to 80 sccm.

7. The in-situ activation method according to claim 5, characterized in that The activation gas flow rate in step (2) is 50-150 sccm.

8. The in-situ activation method according to claim 5, characterized in that The water bath temperature in step (3) is 60-85°C.

9. The in-situ activation method according to claim 5, characterized in that The preparation method of the electrolytic cell comprises the following steps: (1) preparing a hydrogen electrode-supported half-electrolytic cell sheet by tape casting, calendering, or powder dry pressing, wherein the material of the hydrogen electrode support layer is Ni-YSZ, Ni-GDC, or Ni-LSGM, and the electrolyte is YSZ, GDC, SDC, or LSGM; (2) The oxygen electrode powder is prepared by combustion method, solid phase synthesis method or chemical precipitation method, and the oxygen electrode material is SSC-SDC, LSM-YSZ or BSCF-GDC; (3) The oxygen electrode powder and the binder are mixed in a mass ratio of 10:1 to 2:1 to prepare the oxygen electrode slurry, which is then coated on the half-electrolytic cell sheet supported by the hydrogen electrode and calcined at 700 to 1200 °C for 1 to 10 hours.

10. The in-situ activation method according to claim 9, characterized in that: The binder is 6%wt ethyl cellulose in terpineol.

Images