Electrode oxygen evolution potential testing method capable of suppressing current density measurement error

Abstract

The invention relates to the technical field of electrode oxygen evolution potential testing, in particular to an electrode oxygen evolution potential testing method capable of inhibiting a current density measurement error, which comprises the following steps of: fixing the back surface of an electrode on a polymer rod coated with a copper conductive adhesive tape, and connecting the back surface of the electrode with the copper conductive adhesive tape by using silver paste; the current distribution error in the sample preparation process is effectively reduced, the back surface and the side surface of the electrode are insulated and sealed by adopting silicon-based glue, the linear volt-ampere scanning (LSV) test is performed in an electrolyte solution, the interference of back surface and side surface current is effectively eliminated, the experimental result shows that the OEP measurement value of the comprehensively sealed electrode is increased to 1.70 V and is close to the true value, and the accuracy of the test result is improved. According to the method, it is ensured that the real catalytic performance of the electrode can be accurately evaluated, errors caused by overestimation of the current density are reduced, and a reliable basis is provided for electrode material screening and performance optimization.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode oxygen evolution potential testing, in particular to an electrode oxygen evolution potential testing method capable of suppressing current density measurement errors. Background Art

[0002] Oxygen evolution potential (OEP) is one of the important parameters for evaluating the electrocatalytic performance of electrode materials, directly affecting the activity and energy consumption of electrodes in electrochemical reactions. In recent years, electrochemical technology has been widely used in fields such as electrochemical synthesis, among which the oxygen evolution reaction (OEP) is one of the key reactions and is also a key indicator that companies consider when purchasing electrode materials. However, due to differences in equipment, reagents, and testing conditions, OEP measurement results in different laboratories and research environments have significant deviations and may even be far lower than the theoretical value. This difference not only affects the accuracy of the data, but also reduces the comparability between different research results, limiting the promotion and application of new electrode materials.

[0003] During the development of electrode materials, different sample preparation and testing methods have a significant impact on OEP measurements. For example, the exposed electrode area, the contact method with the electrolyte solution, and the uneven current distribution can all lead to underestimation or overestimation of the OEP. Especially when testing small electrode samples of a certain thickness (e.g., 1 cm × 1 cm × 0.5 cm), the current may concentrate at unintended locations on the electrode surface, resulting in an overestimation of the current density at the same potential, thus affecting the true performance evaluation of the electrode material. This phenomenon is particularly prominent in high-performance electrode materials (such as lead dioxide or other efficient oxygen evolution electrodes), potentially obscuring their actual advantages.

[0004] Conventional electrode preparation and testing methods often lack precise control over the effective exposed electrode area, resulting in uneven current distribution and, in turn, affecting accurate OEP measurements. Some studies have attempted to reduce this error by optimizing electrode geometry or adjusting electrolyte concentration, but these methods often require additional processing steps, increasing experimental complexity and cost. Summary of the Invention

[0005] The object of the present invention is to provide a method for testing electrode oxygen evolution potential that can suppress current density measurement errors, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for testing electrode oxygen evolution potential capable of suppressing current density measurement errors comprises the following steps:

[0008] Step 1: Fix the back of the electrode to a polymer rod coated with copper conductive tape and connect the back of the electrode to the copper conductive tape using silver paste to effectively reduce the current distribution error during sample preparation;

[0009] Step 2: The back and sides of the electrode are insulated and sealed with silicone glue, ensuring that only the front of the electrode remains exposed. The silicone glue thoroughly insulates the sides of the electrode and the bottom of the polymer rod, thereby completely isolating the copper conductive tape and the sides of the electrode from the external environment, leaving only the electrode surface in contact with the electrolyte. This treatment further ensures that the current flows only in the predetermined target area, effectively preventing overestimation of the current density;

[0010] Step 3: After the sealing treatment, the electrode is left to stand for 72 hours to allow the silicone glue to cure and form a stable insulating layer. Since the electrode needs to be dried for 72 hours after the insulation treatment, the silicone glue can be fully cured to ensure that the electrode sample has good mechanical and electrochemical stability.

[0011] Step 4: Perform a linear voltammetric sweep (LSV) test in the electrolyte solution and record the potential corresponding to the current density reaching 10 mA / cm² as the oxygen evolution potential (OEP).

[0012] As a preferred solution of the present invention, the silicone-based glue is DuPont 3140 or a material with similar insulation and corrosion resistance properties, and the sealing layer thickness is 0.2 to 0.5 mm.

[0013] As a preferred solution of the present invention, during the fixing process of the electrode sample, the conductive glue used is silver paste, and the amount used is 0.1 to 0.3 g.

[0014] As a preferred solution of the present invention, the electrode sample is placed in a 20° C. environment for 72 hours during the curing process, or placed in a 60° C. environment for 2 to 4 hours to accelerate the curing.

[0015] As a preferred solution of the present invention, the electrode size is 1 cm × 1 cm × 0.5 cm, and the electrode exposure area is strictly controlled in the front area to reduce the overestimation of the current density.

[0016] As a preferred embodiment of the present invention, the back and sides of the electrode are completely sealed, with only the front side exposed to the electrolyte solution. The electrode was subjected to a linear voltammetry (LSV) test in a 0.1 M sodium sulfate solution, and the measured oxygen evolution potential (OEP) reached a relatively high 1.70 V (vs. Ag / AgCl).

[0017] As a preferred solution of the present invention, the electrode sealing treatment significantly reduces the back and side reaction areas, thereby reducing the overestimation of current density and improving the accuracy and reproducibility of oxygen evolution potential (OEP) measurement.

[0018] As a preferred solution of the present invention, the electrode sample is suitable for various electrochemical reaction systems such as water decomposition, electrocatalytic synthesis, and electrolytic hydrogen production, ensuring accurate evaluation of the electrode catalytic performance.

[0019] As a preferred embodiment of the present invention, the electrolyte solution is 0.1 M sodium sulfate, and the counter electrode is a platinum sheet.

[0020] As a preferred solution of the present invention, the oxygen evolution potential (OEP) is usually obtained by recording a linear sweep voltammetry (LSV) curve or a constant current method.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention effectively eliminates interference from the back and side currents by sealing the back and sides of the electrode, leaving only the front exposed to the electrolyte. Experimental results show that the OEP measurement value of the fully sealed electrode is increased to 1.70 V, close to the true value, and significantly higher than that of electrode samples that are not sealed or only have the back sealed. This method ensures that the true catalytic performance of the electrode can be accurately evaluated, reduces the error caused by overestimation of current density, and provides a reliable basis for electrode material screening and performance optimization. The sealing treatment method uses cheap and readily available materials such as silicone glue and silver paste. The process is simple and does not require complex equipment or precision packaging technology. This method is highly compatible with existing electrode fixtures and can be directly applied to various electrode samples. It is particularly suitable for electrochemical reaction systems such as water decomposition and electrocatalytic synthesis, and has wide applicability and operability.

[0023] 2. In the present invention, the unsealed electrode is easily exposed on the back and sides, which can lead to overestimation of current density and underestimation of OEP, thereby affecting the actual application effect of the electrode. By gradually sealing the back and sides of the electrode, the measured OEP value is made closer to the actual oxygen evolution capacity of the electrode, thereby effectively improving the accuracy and credibility of the research data, and making the measured data more conducive to demonstrating the advantages and characteristics of the high OEP of the electrode itself. This method does not require expensive equipment or special materials, the sealing process is simple and low-cost, and is suitable for large-scale promotion and industrial application. The silicone-based glue has high stability after curing, and the electrode maintains good insulation properties during long-term electrolysis, ensuring the durability and reusability of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram comparing linear voltammetric scanning curves of three cases of the structure of the present invention;

[0025] Figure 2 Schematic diagram of the back and side structures of the closed electrode of the present invention;

[0026] Figure 3 It is a schematic diagram of the front exposure structure of the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] For examples, see Figure 1-Figure 3 , the present invention provides a technical solution:

[0029] Example 1: Unsealed Electrode Sample (Using Commercially Available Electrode Holders) In this example, commercially available electrode holders were used, as shown in the attached Figure 2 As shown in the figure, this is equivalent to the electrode sample not undergoing any sealing treatment, and both the front and back sides of the electrode are directly exposed to the electrolyte. Other experimental conditions are as follows: Electrolyte: 0.1 M sodium sulfate ( ) solution; temperature: 20°C; scanning range: open circuit potential to 2.0 V (vs. Ag / AgCl). The final measured OEP is 1.44 V. Figure 3 shown.

[0030] Other experimental conditions are as follows:

[0031] Electrolyte solution: 0.1 M sodium sulfate ( )

[0032] Test temperature: 20 ℃

[0033] Potential scan range: from open circuit potential (OCP) to 2.0 V (vs. Ag / AgCl)

[0034] Scan rate: 0.05 mV / s

[0035] Electrode size: 1 cm × 1 cm

[0036] Reference electrode: Ag / AgCl (saturated KCl)

[0037] Counter electrode: platinum sheet

[0038] The final measured OEP is 1.44 V, which is at a relatively low level.

[0039] Example 2: Sealing the Backside of an Electrode Sample (Side Exposed) In this example, the backside of the electrode sample was sealed to reduce the impact of backside current distribution. However, the electrode side surface was still exposed to the electrolyte, potentially causing some side surface areas to participate in the electrochemical reaction. This experiment aimed to evaluate the effect of sealing the backside of the electrode on oxygen evolution potential (OEP) measurements.

[0040] Other experimental conditions are as follows:

[0041] Electrolyte solution: 0.1 M sodium sulfate ( )

[0042] Test temperature: 20 ℃

[0043] Potential scan range: from open circuit potential (OCP) to 2.0 V (vs. Ag / AgCl)

[0044] Scan rate: 0.05 mV / s

[0045] Electrode size: 1 cm × 1 cm

[0046] Reference electrode: Ag / AgCl (saturated KCl)

[0047] Counter electrode: platinum sheet

[0048] During the linear voltammetry (LSV) scan, the current density gradually increased with increasing potential. When the current density reached 10 mA / cm², the corresponding potential was recorded as the oxygen evolution potential (OEP). The measured OEP was 1.55 V (vs. Ag / AgCl). Figure 3 As shown in the figure, there is a significant improvement compared to the traditional electrode holder. This can be attributed to the fact that after sealing the back side, the measured OEP is improved, but the presence of side reactions still makes the OEP lower than the actual value.

[0049] Example 3: Sealing the Back and Sides of an Electrode Sample (Only the Front Exposed) In this example, the back and side surfaces of the electrode sample were sealed, leaving only the front exposed to the electrolyte. This method aims to minimize current distribution in non-target areas, thereby improving the accuracy and reproducibility of oxygen evolution potential (OEP) measurements.

[0050] Other experimental conditions are as follows:

[0051] Electrolyte solution: 0.1 M sodium sulfate ( )

[0052] Test temperature: 20 ℃

[0053] Potential scan range: open circuit potential (OCP) to 2.0 V (vs. Ag / AgCl)

[0054] Scan rate: 5 mV / s

[0055] Electrode size: 1 cm × 1 cm

[0056] Reference electrode: Ag / AgCl (saturated KCl)

[0057] Counter electrode: platinum sheet

[0058] Sealing method: First use silver paste (such as Kingstar K-818) to fix the back of the electrode on the copper conductive tape.

[0059] Use silicone adhesive (such as DuPont 3140) to evenly coat the back and sides of the electrode to a thickness of approximately 0.3-0.5 mm, ensuring a continuous sealant layer free of bubbles or cracks. Allow the adhesive to cure for 72 hours to form a stable insulating layer.

[0060] In the linear sweep voltammetry (LSV) test, the current density increases with increasing potential. When the current density reaches 10 mA / cm², the corresponding potential is recorded as the OEP. The measured OEP is 1.70 V (vs. Ag / AgCl), which is relatively high. Figure 3 shown.

[0061] By fully sealing the back and sides of the electrode, current is only allowed to occur in the front reaction area of ​​the electrode, eliminating the interference of back and side currents. The main effects include: no overestimation of current density. The current is strictly limited to the front working area, the measurement is more consistent with the actual effective area of ​​the electrode, unnecessary side or back reactions are avoided, and the oxygen evolution potential is accurately measured. The actual effective reaction area of ​​the electrode is consistent with the theory, and the measured OEP reaches the highest value, 1.70 V (vs. Ag / AgCl), which is close to the actual performance level of the electrode.

[0062] This example shows that sealing the back of the electrode can reduce the overestimation of current density to a certain extent and improve the accuracy of OEP. However, if the side exposure is not effectively sealed, the measurement may still be biased. This example further demonstrates the importance of backside sealing in ensuring the true electrocatalytic performance evaluation of the electrode.

[0063] Because both the back and sides of the electrode are exposed to the electrolyte, the current is distributed over a larger area, resulting in current densities of 10 mA / cm² being achieved at lower potentials. This often leads to: an overestimation of the current density—the actual active reaction area of ​​the electrode is much larger than the exposed front surface, resulting in current distribution on both the front and back sides, causing the measurement results to deviate from reality; and an underestimation of the oxygen evolution potential—the oxygen evolution reaction can be observed at lower potentials due to the participation of non-target electrode surfaces in the reaction.

[0064] This example demonstrates that without electrode sealing, the measured OEP is often low, exhibiting a certain degree of deviation. While commercially available electrode clamps are convenient to use, they cannot effectively shield the reaction on the non-working surface of the electrode, resulting in an inflated actual current density, thus affecting the evaluation of the true electrocatalytic performance of the electrode material.

[0065] The working process of the present invention is as follows: When the electrode oxygen evolution potential test method designed by the present invention is used to suppress the current density measurement error, the back of the electrode is fixed on a polymer rod coated with a copper conductive tape, and the back of the electrode is connected to the copper conductive tape using silver paste, which effectively reduces the current distribution error in the sample preparation process. The back and side of the electrode are insulated and sealed with silicone-based glue to ensure that only the front of the electrode remains exposed. The silicone-based glue thoroughly insulates the side of the electrode and the bottom of the polymer rod, thereby completely isolating the copper conductive tape and the side of the electrode from the external environment, leaving only the electrode surface in contact with the electrolyte. This treatment further ensures that the current flows only in the predetermined target area, effectively preventing the overestimation of the current density. After the sealing treatment, the electrode is left to stand for 72 hours to allow the silicone-based glue to cure and form a stable insulating layer. Since the electrode needs to be dried for 72 hours after the insulation treatment, the silicone-based glue can be fully cured, ensuring that the electrode sample has good mechanical stability and electrochemical stability. A linear voltammetric sweep (LSV) test is performed in the electrolyte solution, and the recorded current density reaches 10 The potential corresponding to mA / cm² is taken as the oxygen evolution potential (OEP).

[0066] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for measuring the oxygen evolution potential of an electrode capable of suppressing current density measurement errors, comprising the following steps: Step 1: Fix the back of the electrode to a polymer rod coated with copper conductive tape and connect the back of the electrode to the copper conductive tape using silver paste to effectively reduce the current distribution error during sample preparation; Step 2: The back and sides of the electrode are insulated and sealed with silicone glue, ensuring that only the front of the electrode remains exposed. The silicone glue thoroughly insulates the sides of the electrode and the bottom of the polymer rod, thereby completely isolating the copper conductive tape and the sides of the electrode from the external environment, leaving only the electrode surface in contact with the electrolyte. This treatment further ensures that the current flows only in the predetermined target area, effectively preventing overestimation of the current density; Step 3: After the sealing treatment, the electrode is left to stand for 72 hours to allow the silicone glue to cure and form a stable insulating layer. Since the electrode needs to be dried for 72 hours after the insulation treatment, the silicone glue can be fully cured to ensure that the electrode sample has good mechanical and electrochemical stability. Step 4: Perform a linear voltammetric sweep (LSV) test in the electrolyte solution and record the potential corresponding to the current density reaching 10 mA / cm² as the oxygen evolution potential (OEP).

2. A method for testing electrode oxygen evolution potential capable of suppressing current density measurement error according to claim 1, characterized in that: The silicone-based adhesive is DuPont 3140 or a material with similar insulation and corrosion resistance, and the sealing layer thickness is 0.2 to 0.5 mm.

3. The electrode oxygen evolution potential testing method capable of suppressing current density measurement error according to claim 1, characterized in that: During the fixing process of the electrode sample, the conductive glue used is silver paste, and the amount used is 0.1 to 0.3 g.

4. The electrode oxygen evolution potential testing method capable of suppressing current density measurement error according to claim 1, characterized in that: During the curing process, the electrode sample was placed in a 20° C. environment for 72 hours, or in a 60° C. environment for 2 to 4 hours to accelerate the curing.

5. The electrode oxygen evolution potential testing method capable of suppressing current density measurement error according to claim 1, characterized in that: The electrode size is 1 cm × 1 cm × 0.5 cm, and the electrode exposure area is strictly controlled in the front area to reduce the overestimation of the current density.

6. The electrode oxygen evolution potential testing method capable of suppressing current density measurement error according to claim 1, characterized in that: The back and sides of the electrode are completely sealed, with only the front side exposed to the electrolyte solution. The electrode was subjected to a linear voltammetry (LSV) test in a 0.1 M sodium sulfate solution, and the measured oxygen evolution potential (OEP) reached a high 1.70 V (vs. Ag / AgCl).

7. The electrode oxygen evolution potential testing method capable of suppressing current density measurement error according to claim 1, characterized in that: The electrode sealing treatment significantly reduces the back and side reaction areas, thereby reducing the current density overestimation phenomenon and improving the accuracy and reproducibility of oxygen evolution potential (OEP) measurements.

8. The electrode oxygen evolution potential testing method capable of suppressing current density measurement error according to claim 1, characterized in that: The electrode sample is suitable for various electrochemical reaction systems such as water decomposition, electrocatalytic synthesis, and electrolytic hydrogen production, ensuring accurate evaluation of the electrode catalytic performance.

9. The electrode oxygen evolution potential testing method capable of suppressing current density measurement error according to claim 1, characterized in that: The electrolyte solution is 0.1 M sodium sulfate, and the counter electrode is a platinum sheet.

10. The electrode oxygen evolution potential testing method capable of suppressing current density measurement errors according to claim 1, characterized in that: The oxygen evolution potential (OEP) is usually obtained by recording a linear sweep voltammetry (LSV) curve or a constant current method.

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