An in-situ aem three-electrode test cell

Abstract

The application discloses an in-situ AEM three-electrode test cell, and relates to the field of hydrogen production by electrolysis of water, which comprises an anode plate, one side of the anode plate is provided with a cathode plate, an anion exchange membrane is arranged between the anode plate and the cathode plate, flow channel regions are formed in the cathode plate and the anode plate, a reference electrode cavity is formed below the flow channel region of the cathode plate, the reference electrode cavity is isolated from the flow channel region, a reference electrode is arranged in the reference electrode cavity, and a part of the anion exchange membrane extends into the reference electrode cavity. The independent reference electrode cavity is arranged below the flow channel region of the cathode plate, the reference electrode cavity and the flow channel region are isolated from each other, the possibility that bubbles generated in a reaction area and electrolyte interfere with each other and interfere with the environment in the reference electrode cavity is effectively prevented, and accurate evaluation of intrinsic activity of a catalyst and in-depth exploration of a reaction mechanism are realized.

Description

Technical Field

[0001] This application relates to the field of hydrogen production by water electrolysis, and in particular to an in-situ AEM three-electrode test cell. Background Technology

[0002] Hydrogen energy, as a clean and efficient secondary energy source, has attracted much attention for its development and utilization. Electrolysis of water to produce hydrogen is one of the important ways to achieve green hydrogen production. Among them, anion exchange membrane electrolysis (AEM) technology has shown good application prospects due to its combination of the advantages of low cost of alkaline water electrolysis, the use of non-precious metal catalysts, and the compactness and high efficiency of proton exchange membrane water electrolysis systems.

[0003] In the development of AEM technology, catalyst activity, membrane electrode performance and durability are key evaluation indicators. Accurate and independent testing of the electrochemical behavior of the working electrode (such as cathode or anode) is crucial for understanding the reaction mechanism and optimizing material design.

[0004] However, most commonly used AEM testing devices currently employ a two-electrode system. This system cannot effectively separate the potential responses of the cathode and anode, making it difficult to accurately distinguish the polarization contribution of each electrode and assess the true activity of the catalyst. Especially under long-term operation or dynamic conditions, factors such as bubble accumulation and concentration polarization can further interfere with the accuracy and repeatability of the measurement results and may affect the service life of the testing device due to unstable operating conditions. Utility Model Content

[0005] The purpose of this application is to address the problem that most commonly used AEM testing devices mentioned in the background art employ a two-electrode system, which cannot effectively separate the potential responses of the cathode and anode, making it difficult to accurately distinguish the polarization contribution of each electrode and evaluate the true activity of the catalyst. Especially under long-term operation or dynamic conditions, factors such as bubble accumulation and concentration polarization can further interfere with the accuracy and repeatability of the measurement results, and may affect the service life of the testing device due to unstable operating conditions. This application provides an in-situ AEM three-electrode testing cell.

[0006] To achieve the above objectives, this application specifically adopts the following technical solution: An in-situ AEM three-electrode test cell includes an anode plate, a cathode plate disposed on one side of the anode plate, the anode plate and the cathode plate being disposed opposite each other, an anion exchange membrane sandwiched between the anode plate and the cathode plate, a gas diffusion layer sandwiched between the anion exchange membrane and both the anode plate and the cathode plate, a flow channel region formed on both the cathode plate and the anode plate, a reference electrode chamber formed below the flow channel region of the cathode plate, the reference electrode chamber being isolated from the flow channel region, a reference electrode disposed in the reference electrode chamber, and a portion of the anion exchange membrane extending into the reference electrode chamber and contacting the end of the reference electrode to form an ion pathway.

[0007] By adopting the above technical solution, an independent reference electrode chamber is set below the flow channel area of ​​the cathode plate, which isolates the reference electrode chamber from the flow channel area. This effectively prevents the possible crosstalk between the bubbles and electrolyte generated in the reaction zone and the environment in the reference electrode chamber, enabling accurate evaluation of the intrinsic activity of the catalyst and in-depth exploration of the reaction mechanism. It also effectively avoids the possible leakage of active materials from the reference electrode, preventing their contamination of the electrolyte and catalyst in the main reaction zone, thereby improving the long-term chemical stability and service life of the testing system.

[0008] Furthermore, insulating gaskets are provided on both sides of the anion exchange membrane, and the insulating gaskets have openings corresponding to the flow channel region and the reference electrode chamber. The flow channel region and the opening of the reference electrode chamber are physically separated by the insulating gaskets.

[0009] By adopting the above technical solution, the insulating gasket achieves physical isolation between the flow channel region and the reference electrode chamber, thereby effectively preventing crosstalk between bubbles and electrolyte generated in the reaction zone and the environment inside the reference electrode chamber, and ensuring the stability of the reference potential. Furthermore, the width of the insulating pad is 0.5mm-5mm.

[0010] By adopting the above technical solution, the insulating pad is set between 0.5mm and 5mm, which can ensure reliable isolation while taking into account the wettability of the membrane.

[0011] Furthermore, a reference electrode clamping module is provided between the reference electrode and the reference electrode chamber, the reference electrode is sealed and installed in the reference electrode clamping module, and the reference electrode clamping module is sealed and connected to the opening end of the reference electrode chamber.

[0012] By adopting the above technical solution and setting up a reference electrode clamping module with a sealed structure, the reference electrode can be quickly installed, reliably fixed and effectively sealed, which fundamentally avoids the leakage of electrolyte in the reference electrode cavity and improves the reliability of the device.

[0013] Furthermore, an annular boss is fixed at one end of the reference electrode clamping module that extends into the reference electrode chamber. The inner diameter of the annular boss is adapted to the outer diameter of the reference electrode, and is used to limit the position of the reference electrode.

[0014] By adopting the above technical solution and setting an annular boss for axial positioning, it is possible to ensure that the reference electrode is installed at the same depth and contact point each time, which greatly improves the repeatability of the experiment and the comparability of the measurement data.

[0015] Furthermore, the reference electrode is one of the following: a mercury / mercury oxide electrode, a silver / silver oxide electrode, a mercury / mercurous sulfate electrode, or a reversible hydrogen electrode.

[0016] By adopting the above technical solution, using one of the following electrodes that are stable in alkaline environments and have good reproducibility: mercury / mercuric oxide electrode, silver / silver oxide electrode, mercury / mercurous sulfate electrode, or reversible hydrogen electrode, a precise and stable potential reference can be provided for the entire testing system, ensuring the accuracy of the measurement results.

[0017] Furthermore, electrolyte channels are provided in the flow channel areas of the anode plate and the cathode plate, and electrolyte inlets and outlets are provided on both the anode plate and the cathode plate, with the electrolyte inlets and outlets connected to the corresponding electrolyte channels.

[0018] By adopting the above technical solution, the flow channels in the flow channel area are designed as serpentine or other flow channels that can cover the flow channel area as much as possible, thereby increasing the flow channel length and the contact time between the electrolyte and the electrode, promoting the uniform transport of reactants and products, avoiding local concentration polarization, and making the test conditions more uniform and the data more reliable.

[0019] Furthermore, multiple bolt fixing holes are provided around both the anode plate and the cathode plate, and the anode plate and the cathode plate are fastened together by bolts.

[0020] The components are secured by bolt holes that are symmetrically distributed around the perimeter, which ensures uniform force distribution among the components, achieves good electrical contact and interface sealing, and prevents damage or leakage of the membrane electrode due to uneven clamping force.

[0021] In summary, this application includes at least one of the following beneficial effects; 1. This application successfully constructs a reliable in-situ three-electrode testing system by setting an independent reference electrode chamber on the cathode plate and directly establishing a stable ion pathway using an extended ion exchange membrane. Then, an insulating gasket physically isolates the reference electrode chamber from the main reaction channel, enabling accurate and independent measurement and study of the potential, current, and interface state of the working electrode during the actual reaction process. This allows for precise evaluation of the intrinsic activity of the catalyst and in-depth exploration of the reaction mechanism. It also effectively avoids interference from bubbles and contaminants in the reaction zone, ensuring the extreme stability of the reference potential under long-term high-temperature alkaline testing conditions. Furthermore, the physical isolation and sealing design effectively prevents bubbles in the reaction zone from interfering with the reference potential, ensuring its extreme stability under long-term high-temperature alkaline testing conditions. It also effectively prevents the possible leakage of active materials from the reference electrode, preventing contamination of the electrolyte and catalyst in the main reaction zone, thereby improving the long-term chemical stability and service life of the testing system.

[0022] 2. In this application, the reference electrode is installed in the inner hole of the reference electrode clamping module by means of an O-ring seal. One end of the reference electrode clamping module has an external thread that mates with the internal thread at the opening of the reference electrode chamber to achieve a sealed connection, ensuring the airtightness of the reference electrode chamber and preventing electrolyte leakage. To ensure that the contact position between the reference electrode and the ion exchange membrane is consistent during each assembly, an annular boss is used to limit the position of the reference electrode clamping module, thereby achieving the goal of enabling rapid installation, reliable fixation, and effective sealing of the reference electrode, reducing electrolyte leakage in the reference electrode chamber, and improving the reliability of the device. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the first three-dimensional structure of the in-situ AEM three-electrode test cell in this application; Figure 2 This is a schematic diagram of the disassembled three-dimensional structure of the in-situ AEM three-electrode test cell in this application; Figure 3 This is a partial structural schematic diagram of the in-situ AEM three-electrode test cell in this application.

[0024] Explanation of reference numerals in the attached figures: 1. Anode plate; 2. Cathode plate; 3. Anion exchange membrane; 4. Flow channel region; 5. Reference electrode chamber; 6. Reference electrode; 7. Insulating gasket; 8. Reference electrode clamping module; 9. Annular boss; 10. Electrolyte inlet; 11. Electrolyte outlet; 12. Bolt fixing hole; 13. Gas diffusion layer. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0026] This application discloses an in-situ AEM three-electrode test cell.

[0027] Reference Figure 1 , Figure 2 and Figure 3 An in-situ AEM three-electrode test cell includes an anode plate 1, a cathode plate 2 disposed on one side of the anode plate 1, the anode plate 1 and the cathode plate 2 being disposed opposite each other, an anion exchange membrane 3 sandwiched between the anode plate 1 and the cathode plate 2, and a gas diffusion layer 13 sandwiched between the anion exchange membrane 3 and both the anode plate 1 and the cathode plate 2, a flow channel region 4 being formed on both the cathode plate 2 and the anode plate 1, a reference electrode chamber 5 being formed below the flow channel region 4 of the cathode plate 2, the reference electrode chamber 5 being isolated from the flow channel region 4, a reference electrode 6 being disposed in the reference electrode chamber 5, and a portion of the anion exchange membrane 3 extending into the reference electrode chamber 5 and contacting the end of the reference electrode 6 to form an ion pathway.

[0028] In addition, insulating pads 7 are provided on both sides of the anion exchange membrane 3. The insulating pads 7 have openings corresponding to the flow channel region 4 and the reference electrode chamber 5. The openings of the flow channel region 4 and the reference electrode chamber 5 are physically separated by the insulating pads 7.

[0029] A corresponding catalyst layer is added between the gas diffusion layer 13 and the anion exchange membrane 3. The anode plate 1 and the cathode plate 2 are fixed together. The flow channel region 4 on the anode plate 1 and the cathode plate 2 is used for electrolyte flow. Below the flow channel region 4 of the cathode plate 2, an independent reference electrode chamber 5 is machined. The reference electrode chamber 5 is physically isolated from the flow channel region 4. The reference electrode 6 is placed in the reference electrode chamber 5. The anion exchange membrane 3 is appropriately extended at the corresponding position so that a part of it can extend into the interior of the reference electrode chamber 5 and directly contact the end of the reference electrode 6, thereby forming an ion pathway without the need for an additional salt bridge. The insulating gasket 7 set between the anode plate 1 and the cathode plate 2 is made of an alkali-resistant corrosion resistant material and has been precisely machined with... The openings corresponding to the flow channel region 4 and the reference electrode chamber 5 are physically separated by the solid material of the insulating gasket 7. By independently separating the flow channel region 4 and the reference electrode chamber 5, and using the insulating gasket 7 to separate them, the possibility of crosstalk between the bubbles and electrolyte generated in the reaction zone and the environment inside the reference electrode chamber 5 can be effectively prevented. This allows for accurate evaluation of the intrinsic activity of the catalyst and in-depth exploration of the reaction mechanism. It also effectively avoids the possible leakage of active materials from the reference electrode 6, preventing contamination of the electrolyte and catalyst in the main reaction zone, thereby improving the long-term chemical stability and service life of the testing system.

[0030] Reference Figure 1 and Figure 2The width of the insulating pad 7 is 0.5mm-5mm. If the width of the insulating pad 7 is too small, such as less than 0.5mm, it may lead to insufficient isolation strength or processing difficulties. If the width is too large, such as greater than 5mm, it will occupy too much of the reaction area, affecting the effective wetting and current distribution of the anion exchange membrane 3. By setting the insulating pad 7 between 0.5mm and 5mm, reliable isolation can be ensured while also taking into account the wettability of the membrane.

[0031] Reference Figure 1 and Figure 2 A reference electrode clamping module 8 is provided between the reference electrode 6 and the reference electrode chamber 5. The reference electrode 6 is sealed and installed on the reference electrode clamping module 8, and the reference electrode clamping module 8 is sealed and connected to the opening end of the reference electrode chamber 5.

[0032] In addition, an annular boss 9 is fixed at one end of the reference electrode clamping module 8 that extends into the reference electrode chamber 5. The inner diameter of the annular boss 9 is adapted to the outer diameter of the reference electrode 6, and is used to limit the position of the reference electrode 6.

[0033] The reference electrode 6 is installed in the inner hole of the reference electrode clamping module 8 by an O-ring seal. One end of the reference electrode clamping module 8 has an external thread that engages with the internal thread at the opening of the reference electrode chamber 5 to achieve a sealed connection, ensuring the airtightness of the reference electrode chamber 5 and preventing electrolyte leakage. To ensure that the contact position between the reference electrode 6 and the ion exchange membrane is consistent during each assembly, an annular boss 9 is used to limit the reference electrode clamping module 8. By installing the reference electrode 6 into the reference electrode clamping module 8 and then using the annular boss 9 to limit the reference electrode clamping module 8, the reference electrode 6 can be quickly installed, reliably fixed, and effectively sealed, fundamentally avoiding electrolyte leakage in the reference electrode chamber and improving the reliability of the device.

[0034] Reference Figure 1 and Figure 2 The reference electrode 6 is one of the following: mercury / mercury oxide electrode, silver / silver oxide electrode, mercury / mercurous sulfate electrode, or reversible hydrogen electrode. Before testing, an electrolyte of the same concentration as the main channel, a 1 mol / L KOH solution, is injected into the reference electrode chamber 5. By employing one of these electrodes—mercury / mercury oxide electrode, silver / silver oxide electrode, mercury / mercurous sulfate electrode, or reversible hydrogen electrode—which offers potential stability and reproducibility in an alkaline environment, a precise and stable potential reference can be provided for the entire testing system, ensuring the accuracy of the measurement results.

[0035] Reference Figure 2 and Figure 3Electrolyte channels are formed in the flow channel region 4 on the anode plate 1 and the cathode plate 2. Both the anode plate 1 and the cathode plate 2 have electrolyte inlets 10 and electrolyte outlets 11, which are connected to their respective electrolyte channels. The flow channels within the flow channel region 4 are designed in a serpentine or other manner to cover the flow channel region 4 as much as possible. The electrolyte flows into the flow channel from the electrolyte inlet 10 on the electrode plate, undergoes sufficient mass and charge exchange, and then flows out from the electrolyte outlet 11. By adopting a serpentine or other flow channel design to cover the flow channel region 4 as much as possible, the flow channel length and the contact time between the electrolyte and the electrode are increased, promoting uniform transport of reactants and products, avoiding localized concentration polarization, and making the test conditions more uniform and the data more reliable.

[0036] Reference Figure 1 , Figure 2 and Figure 3 Both the anode plate 1 and the cathode plate 2 have multiple bolt holes 12 around their perimeter, and the anode plate 1 and cathode plate 2 are fastened together with bolts. To achieve a tight and sealed test cell, multiple bolt holes 12 are symmetrically machined at the four corners and edges of the anode plate 1 and cathode plate 2. During assembly, high-strength bolts are passed through these holes sequentially and tightened with nuts. The components are secured by bolt holes 12 that are symmetrically distributed around the perimeter, which ensures uniform force distribution among the components, achieves good electrical contact and interface sealing, and prevents damage or leakage of the membrane electrode due to uneven clamping force.

[0037] Working principle: After the entire test cell is assembled, the electrolyte is continuously pumped into the flow channel region 4 of the anode plate 1 and the cathode plate 2, and wets the entire anion exchange membrane 3 and gas diffusion layer 13. A catalyst layer is filled between the anion exchange membrane 3 and the gas diffusion layer 13. When current is applied through the external circuit, an oxygen evolution reaction occurs at the anode and a hydrogen evolution reaction occurs at the cathode. The generated hydrogen and oxygen are respectively led out through the gas diffusion layer 13 of the cathode and anode to the corresponding flow channels. The reference electrode 6, located in the reference electrode chamber 5 of the cathode plate 2, establishes an ion exchange membrane connection with the entire membrane electrode system through the extended portion of the anion exchange membrane 3 in direct contact with it. In this conductive path, the reference electrode 6 provides a stable and constant potential reference. An external electrochemical workstation can accurately measure the potential of the working electrode (anode or cathode) relative to this reference electrode 6. Through this design, the potential responses of the anode and cathode are successfully decoupled, enabling accurate and independent evaluation of the intrinsic activity, polarization behavior, and stability of either electrode, especially the catalyst electrode under test. This solves the technical problem that traditional two-electrode systems cannot distinguish the contributions of the anode and cathode. At the same time, the independent reference electrode chamber 5 effectively avoids mutual interference from bubbles and possible contaminants in the reaction zone, ensuring the accuracy and stability of long-term testing.

Claims

1. An in-situ AEM three-electrode test cell, comprising an anode plate (1), characterized in that: A cathode plate (2) is provided on one side of the anode plate (1). The anode plate (1) and the cathode plate (2) are arranged opposite to each other. An anion exchange membrane (3) is sandwiched between the anode plate (1) and the cathode plate (2). A gas diffusion layer (13) is sandwiched between the anion exchange membrane (3) and the anode plate (1) and the cathode plate (2). A flow channel region (4) is opened on both the cathode plate (2) and the anode plate (1). A reference electrode chamber (5) is opened below the flow channel region (4) of the cathode plate (2). The reference electrode chamber (5) is isolated from the flow channel region (4). A reference electrode (6) is provided in the reference electrode chamber (5). A part of the anion exchange membrane (3) extends into the reference electrode chamber (5) and contacts the end of the reference electrode (6) to form an ion passage.

2. The in-situ AEM three-electrode test cell according to claim 1, characterized in that: Insulating pads (7) are provided on both sides of the anion exchange membrane (3). The insulating pads (7) have openings corresponding to the flow channel region (4) and the reference electrode chamber (5). The openings of the flow channel region (4) and the reference electrode chamber (5) are physically separated by the insulating pads (7).

3. The in-situ AEM three-electrode test cell according to claim 2, characterized in that: The width of the insulating pad (7) is 0.5mm-5mm.

4. The in-situ AEM three-electrode test cell according to claim 1, characterized in that: A reference electrode clamping module (8) is provided between the reference electrode (6) and the reference electrode chamber (5). The reference electrode (6) is sealed and installed on the reference electrode clamping module (8). The reference electrode clamping module (8) is sealed and connected to the opening end of the reference electrode chamber (5).

5. The in-situ AEM three-electrode test cell according to claim 4, characterized in that: The reference electrode clamping module (8) has an annular boss (9) fixed at one end that extends into the reference electrode chamber (5). The inner diameter of the annular boss (9) is adapted to the outer diameter of the reference electrode (6) and is used to limit the position of the reference electrode (6).

6. The in-situ AEM three-electrode test cell according to claim 1, characterized in that: The reference electrode (6) is one of the following: mercury / mercury oxide electrode, silver / silver oxide electrode, mercury / mercurous sulfate electrode, and reversible hydrogen electrode.

7. The in-situ AEM three-electrode test cell according to claim 1, characterized in that: Electrolyte channels are provided in the flow channel area (4) on the anode plate (1) and the cathode plate (2). Electrolyte inlet (10) and electrolyte outlet (11) are provided on both the anode plate (1) and the cathode plate (2). The electrolyte inlet (10) and the electrolyte outlet (11) are connected to the corresponding electrolyte channels.

8. The in-situ AEM three-electrode test cell according to claim 7, characterized in that: The anode plate (1) and the cathode plate (2) are provided with multiple bolt fixing holes (12) around their perimeters, and the anode plate (1) and the cathode plate (2) are fastened together with bolts.

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