Preparation method of coating part, proton exchange membrane water electrolyser and part

Abstract

The invention provides a preparation method of a coating part, a proton exchange membrane water electrolyser and a component, and the preparation method comprises the following steps: carrying out electrochemical deposition on the surface of the conductive component of the proton exchange membrane water electrolyser by adopting an electric brush plating mode; wherein the electric brush plating is configured as follows: a precious metal or precious metal alloy coating is only formed in a preset target area on the surface of the conductive part, and the target area is a rough peak area on the microscopic scale on the surface of the conductive part, so that when the conductive part is pressed and assembled with other parts at intervals in the proton exchange membrane water electrolyser, the precious metal or precious metal alloy coating is formed; the rough peak region can form micro-viewpoint contact with other parts; by controlling the plating area of brush plating, the precious metal or precious metal alloy coating preferentially covers the rough peak area, so that a functional coating is prevented from being formed in the area except the rough peak area or the non-contact area on the surface of the conductive component. The coating adhesive force is improved, precious metal waste is reduced, the production efficiency is improved, the corrosion resistance and conductivity of components are enhanced, and the service life of the electrolytic bath is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen energy, and in particular to a preparation method of a coated part, a proton exchange membrane water electrolyzer and a part. BACKGROUND

[0002] Hydrogen energy plays a huge role in replacing non-renewable energy because hydrogen has the advantages of abundant source, high combustion value and zero pollutant emission. Using renewable energy to electrolyze water to produce hydrogen not only can produce high-purity hydrogen, but also can greatly reduce carbon emissions. Although the alkaline electrolyzer technology is mature and widely commercialized, its long start-up time, low current density and working pressure, and low hydrogen purity limit its development. Proton exchange membrane water electrolyzer (PEMWE) has the advantages of high current density, wide power range, high hydrogen purity and compact structure, which makes it one of the most critical technology paths in the development of green hydrogen production. Metal materials (especially titanium metal materials) and carbon-based materials have excellent electrical conductivity, so they are widely used in the preparation of gas diffusion layer (GDL) and bipolar plate (BP) in proton exchange membrane electrolyzer (PEMWE). However, the anode of proton exchange membrane water electrolyzer (PEMWE) has high working potential and is in a harsh environment of acidity and easy oxidation. Under long-term operation of the electrolyzer, a thick passivation layer (oxidation layer) will form on the surface of titanium-based materials, and other metal materials will corrode, resulting in increased contact resistance and the precipitation of harmful cations. At the same time, there is a large amount of hydrogen gas in the cathode, and metal materials are prone to hydrogen embrittlement. Recent studies have shown that the oxidation layer of titanium metal in contact with amorphous catalysts will produce Schottky contact, which will hinder the transmission of electrons and affect the performance of electrolysis. These problems need to be solved by coating the surface of the components with noble metals (gold, platinum, iridium, etc.). Since the electron transport and electrochemical reaction between the components of the electrolyzer only occur at the contact points between the components, these areas are subject to high mechanical stress, chemical corrosion and other harsh conditions, and electron transport barriers. In order to increase the utilization rate of the coating and reduce the load of the noble metal coating, the best coating position is the contact part between the components. At the microscale (nanometers to microns), the contact between components is composed of many point contacts, so even if two components are tightly attached together at the macroscale (millimeters to centimeters), there are still a large number of uncontacted areas at the microscale, which requires partitioning the components at the microscale to further reduce the use of noble metal coatings. Currently, physical vapor deposition, immersion plating (the object needs to be completely immersed in the plating solution) and other coating methods are commonly used to prepare partitioned coatings by shielding the areas that do not need to be coated.

[0003] Physical vapor deposition (PVD) coatings involve directly depositing target atoms onto the component surface. Since the deposited atoms and substrate lack chemical bonds, adhesion is poor, leading to coating detachment over time, reduced electrolytic cell lifespan, and higher maintenance costs. Furthermore, target atoms can deposit at any location on the component surface, inevitably affecting non-contact areas within the microstructure of the components. Immersion plating, due to the plating solution penetrating into the porous structure of the gas diffusion layer, inevitably involves internal electrodeposition, resulting in coating waste. Therefore, both PVD and immersion plating cannot avoid coating non-contact areas at the microscale, leading to low coating utilization, high load capacity, and increased electrolytic cell costs. Partitioned coating requires shielding of non-contact areas, which is inefficient and costly for complex components. Currently, partitioned coatings are performed at a macroscale, while actual contact between electrolytic cell components is at a microscale; there are currently no examples of microscale coating or partitioned coating for contact areas between electrolytic cell components. Summary of the Invention

[0004] This invention provides a method for preparing coated parts, a proton exchange membrane water electrolyzer and components, which at least helps to solve the technical problems that direct use of physical vapor deposition and immersion electroplating cannot avoid the use of coatings in microscale non-contact areas, resulting in low coating utilization, high load, and increased electrolyzer costs; and that partitioned coating requires shielding of non-contact areas, which leads to low efficiency and increased costs in processing structurally complex components.

[0005] The technical solution of the present invention is as follows: On the one hand, a method for preparing a coated part is provided, including: Electrochemical deposition was performed on the surface of conductive components in a proton exchange membrane water electrolyzer using an electrobrush plating method. The electroplating is configured to form a noble metal or noble metal alloy coating only in a predetermined target area on the surface of the conductive component. The target area is a rough peak area on the surface of the conductive component at a microscale, so that when the conductive component is pressed and assembled with other components at intervals in a proton exchange membrane water electrolyzer, the rough peak area can form microscopic contact with other components. By controlling the plating area of ​​the electroplating, the precious metal or precious metal alloy coating is preferentially applied to the rough peak area, thereby avoiding the formation of functional coatings in areas other than the rough peak area or in non-contact areas on the surface of the conductive component.

[0006] In one alternative embodiment, the conductive component is selected from at least one of a gas diffusion layer, a bipolar plate, a catalyst layer, and a current collector.

[0007] In an alternative embodiment, when the conductive component is a gas diffusion layer, the target region is located on its surface for contacting the catalyst layer; and / or, When the conductive component is a bipolar plate, the target region is located on the surface of a raised ridge in its flow channel.

[0008] In one alternative embodiment, prior to the electroplating step, a step of surface activation of the conductive component is included, wherein the surface activation is used to remove the surface oxide layer and increase the surface energy.

[0009] In one alternative embodiment, the surface activation step includes immersing the conductive component in an acidic etching solution for chemical etching. The chemical etching process uses a hydrochloric acid solution with a concentration of 1 wt% to 38 wt% and is carried out at a temperature of 10°C to 54°C for 1 to 48 hours.

[0010] In one optional implementation, the electroplating method is carried out in the following manner: Connect the conductive component to the negative terminal of the power supply as a cathode; A movable plating solution carrier adsorbed with the brush plating solution is connected to the positive terminal of the power supply as the anode. Move the anode so that it remains in contact with the target area on the surface of the conductive component and brush it.

[0011] In one optional embodiment, the brush plating solution is a brush plating solution of gold, platinum, iridium, ruthenium or their alloys; The movable plating solution carrier is made of cotton, wool, sponge, polypropylene (PP) based absorbent cotton, or superabsorbent polymer (SAP) resin.

[0012] In one alternative embodiment, the coating thickness formed during the brushing process is from 0.1 nanometers to 20 micrometers.

[0013] On the other hand, a proton exchange membrane water electrolyzer component is provided, which is prepared by any of the methods described above. The surface of the component has a discontinuously distributed noble metal or noble metal alloy coating, and the distribution position of the noble metal or noble metal alloy coating is highly spatially correlated with the distribution of rough peak regions on the surface of the component at the microscale. The noble metal or noble metal alloy coating mainly covers the rough peak regions.

[0014] In another aspect, a proton exchange membrane water electrolyzer is provided, comprising at least one of the proton exchange membrane water electrolyzer components described above.

[0015] The coated parts prepared by the method provided in this embodiment of the invention have at least the following beneficial effects: This invention addresses the problem of poor adhesion and easy peeling of coatings prepared by physical vapor deposition (PVD). It selects electrochemical deposition for coating preparation, where the coating chemically bonds to the substrate, improving adhesion. Furthermore, it addresses the issue of ineffective coating utilization in immersion plating and PVD when areas not requiring coating are not shielded. This invention employs a special brush plating method to prepare coatings on the surface of electrolytic cell components, applying the coating only to the areas where the brush plating device contacts the component surface. Compared to methods that require shielding before partitioned plating, this method eliminates the shielding step, reducing the number of partitioned coating preparation steps, improving production efficiency, lowering production costs, and reducing the steps involved in recovering precious metals from shielded areas, further enhancing production efficiency. It also fills the gap in microscale partitioned plating, further reducing the use of precious metal coatings. Compared with traditional coating preparation methods, the method proposed in this invention has the following advantages: 1. It improves the adhesion of the coating, increases the service life of the electrolyzer, and reduces maintenance costs; 2. It improves the corrosion resistance and conductivity of the components; 3. It reduces the amount of precious metals used and lowers the cost of the electrolyzer; 4. It improves the production efficiency of partitioned coating; 5. Partitioned coating is performed at both the macroscopic and microscopic scales, improving the utilization rate of the coating. Therefore, the above-mentioned partitioned coating preparation method for coated parts has great application prospects in reducing the use of precious metals, improving the performance of proton exchange membrane electrolyzers (PEMWE), and large-scale production using brush plating technology. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the brush plating steps for preparing the gas diffusion layer surface partition coating in Example 1 (showing the coating deposition in the contact area between the cotton head and the GDL).

[0017] Figure 2 This is a schematic diagram of the brush plating process for preparing the coating on the surface of the bipolar plate flow channel protrusion ridge in Example 2 (showing the coating deposition in the contact area between the cotton head and the ridge).

[0018] Figure 3 This is a comparison diagram of the contact resistance of the embodiments and comparative examples of the present invention.

[0019] Figure 4 This is a comparison diagram of the polarization curves of the embodiments and comparative examples of the present invention. Detailed Implementation

[0020] Embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0021] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0022] On the one hand, a method for preparing a surface-partitioned coated part is provided, including: Electrochemical deposition was performed on the surface of conductive components of a proton exchange membrane water electrolyzer (PEMWE) using an electroplating method. Among them, the electroplating is configured to form a noble metal or noble metal alloy coating only in a preset target area on the surface of the conductive component. The target area is a rough peak area on the surface of the conductive component at a microscale, so that when the conductive component is pressed and assembled with other components at intervals in PEMWE, the rough peak area can form microscopic contact with other components. By controlling the plating area of ​​the brush plating, the precious metal or precious metal alloy coating is preferentially applied to the rough peak area, while avoiding the formation of functional coatings in areas other than the rough peak area or in non-contact areas on the surface of the conductive component.

[0023] The method provided in this embodiment of the invention has at least the following beneficial effects: The method provided in this invention provides the following advantages: 1. Improves coating adhesion, increases the service life of the electrolyzer, and reduces maintenance costs; 2. Improves the corrosion resistance and conductivity of components; 3. Reduces the amount of precious metals used, thus lowering the cost of the electrolyzer; 4. Improves the production efficiency of partitioned coating; 5. Partitioned coating is performed at both macroscopic and microscopic scales, improving the utilization rate of the coating. Therefore, the above-mentioned method for preparing partitioned coatings on the surface of coated parts has excellent application prospects in reducing the use of precious metals, improving the performance of proton exchange membrane electrolyzers (PEMWE), and large-scale production using brush plating technology.

[0024] This invention creatively utilizes the inherent "local contact deposition" physical characteristic of the "electroplating" process to achieve automatic identification and selective enhancement of "rough peak regions." For example, in actual operation, the target region can be identified first. In this invention, the target region is not defined by external patterning methods such as photolithography or masking, but is determined by the inherent microstructure (roughness) of the component surface and its "function" in assembly (forming electrical contact points). These "rough peak regions" are the peaks of the surface profile.

[0025] 2. Setting up electroplating: During operation, a brush head (anode) adsorbed with plating solution is moved across the surface of the component (cathode). The contact between the brush head and the surface is dynamic and localized. Since the micro-roughness peaks are the high points of the surface, the brush head will naturally, more frequently and closely engage in physical contact and electrochemical interaction with these peak regions during its movement.

[0026] 3. Achieving preferential coverage: At the aforementioned contact points, the current density is high, and ion exchange is sufficient, thus noble metal ions are preferentially reduced and deposited. However, for microscopic recessed areas or macroscopic non-contact areas, due to weak or no brush head contact, electrochemical reactions are difficult to occur effectively, thereby "avoiding" the formation of functional coatings. This is essentially an intelligent matching of process characteristics and functional requirements.

[0027] This invention completely solves the problem of wasting precious metals in "non-functional areas" caused by physical vapor deposition (complete coverage) and immersion plating (penetration into the interior) in the prior art. Almost the entire coating material is used to construct the actual conductive channel, significantly reducing the precious metal load compared to existing technologies and directly and substantially reducing the raw material cost of PEMWE.

[0028] Because the coating is precisely positioned on the "microscopic roughness peaks" that bear the mechanical contact forces and current transmission, it directly strengthens the weakest contact points. This significantly reduces the contact resistance between components (e.g., Figure 3 As shown, this invention improves the overall voltage efficiency of the electrolytic cell. Simultaneously, the coating produced by electrochemical deposition exhibits strong adhesion and is not easily peeled off during long-term pressing and start-stop cycles, ensuring performance durability. This invention eliminates the need to design, manufacture, and precisely align a micromask for each component (an expensive and difficult technique). By utilizing the component's own morphology and the characteristics of the brush plating process to "self-select" deposition areas, the fabrication of functional coatings on complex microstructures becomes simple, rapid, and cost-effective, laying the foundation for mass production.

[0029] In one alternative embodiment, the conductive component is selected from at least one of a gas diffusion layer, a bipolar plate, a catalyst layer, and a current collector.

[0030] This invention allows the core methods to be specifically applied to all critical conductive components in a PEMWE. For example, plating the GDL optimizes its interface with the catalyst layer; plating the ridges of the BP reduces its contact resistance with the GDL. This ensures that critical interfaces along the entire electron transport path are strengthened, systematically improving electrolyzer performance rather than providing localized improvements.

[0031] In an alternative embodiment, when the conductive component is a gas diffusion layer, the target region is located on its surface for contacting the catalyst layer; and / or, When the conductive component is a bipolar plate, the target area is located on the surface of the raised ridge in its flow channel.

[0032] This invention employs a microscopic peak-region selective coating on the plane of GDL in contact with the catalyst layer. This enhances electron transport from the bulk phase to the reaction sites without clogging the porous structure, directly improving reaction efficiency. Figure 4 Significant performance improvement in Example 1 (in Chinese).

[0033] Coating the surface of the BP channel ridges ensures efficient electron collection and transfer from the bipolar plates to the GDL. The ridges are also the primary areas bearing assembly pressure; the coating enhances their pressure resistance and conductivity. This precise positioning targets the area with the greatest impact on performance.

[0034] In one alternative embodiment, prior to the electroplating step, a step of surface activation of the conductive component is included, wherein surface activation is used to remove the surface oxide layer and increase the surface energy.

[0035] It should be noted that surface activation is a key pretreatment to ensure high adhesion of the brush-plated coating. Acidic chemical etching (such as with hydrochloric acid) can effectively remove the inert oxide layer (TiO2) on the surface of materials such as titanium, exposing the active metal substrate and increasing surface roughness (i.e., creating or exposing more "microscopic roughness peaks"). This not only makes the subsequent electrochemical deposition reaction easier to occur and the resulting metal-metal bonds stronger, but also, by moderately increasing the roughness, creates a more ideal basic morphology for the "microscopic peak region selective deposition" of this invention, making the beneficial effects more prominent.

[0036] The oxide layer can also be removed by grinding and polishing, plasma sputtering, electrolysis, heat treatment, high-pressure water jetting, sandblasting, etc.

[0037] In this embodiment of the invention, coatings can also be prepared on the surface of electrolytic cell components such as catalyst layer, current collector (current collector), and end plate.

[0038] In one alternative embodiment, the surface activation step includes immersing the conductive component in an acidic etching solution for chemical etching. Chemical etching is performed using a hydrochloric acid solution with a concentration of 1 wt% to 38 wt% at a temperature of 10°C to 54°C for 1 to 48 hours.

[0039] This embodiment defines a preferred activation process window. This parameter range is an experimentally verified balance point: if the concentration, temperature, and time are too low, the oxide layer will not be completely removed, affecting the adhesion; if they are too high, it may lead to excessive corrosion of the substrate, damaging the mechanical strength or surface morphology. Etching within this preferred range can stably obtain a clean substrate surface with moderate activity and suitable microstructure, providing a reliable guarantee for subsequent high-quality selective brush plating, ensuring process reproducibility and product performance consistency.

[0040] In one alternative implementation, the electroplating method is carried out in the following manner: Connect the conductive component to the negative terminal of the power supply as the cathode; A movable plating solution carrier adsorbed with the brush plating solution is connected to the positive terminal of the power supply as the anode. Move the anode to keep it in contact with the target area on the surface of the conductive component and brush it.

[0041] This invention clarifies the basic circuit connections and operation methods of brush plating. Using the component as the cathode ensures that noble metal cations can be reduced and deposited on its surface. The use of a "movable" anolyte carrier (such as a brush head) is the physical basis for achieving "localized contact" and "area control." This limitation clearly distinguishes this invention from "electroplating" processes that require the entire component to be immersed in the electrolyte, emphasizing its essential nature of localized processing.

[0042] In one optional embodiment, the brush plating solution is a brush plating solution of gold, platinum, iridium, ruthenium or their alloys; The movable plating solution carrier can be made of cotton, wool, sponge, polypropylene (PP) based absorbent cotton, or super absorbent polymer (SAP) material.

[0043] Understandably, gold, platinum, iridium, ruthenium, and their alloys are known precious metals with excellent corrosion resistance and high conductivity in PEMWE (high-voltage, high-acid) environments. Selecting their corresponding brush plating solutions ensures that the prepared coating meets the long-term use requirements under extreme operating conditions, which is a necessary condition for achieving long-life electrolytic cells.

[0044] Materials such as cotton balls and sponges are porous, soft, and highly absorbent. They can effectively absorb and maintain contact between the plating solution and the cathode, while their softness ensures that they can adapt to the micro-undulations of the surface during brushing and maintain good contact with the "micro-rough peaks." These are key features that enable the "peak region preferential deposition" effect.

[0045] For example, the brush plating solution can also be a single metal brush plating solution such as platinum, iridium, nickel, ruthenium, tantalum, copper, zinc, silver, iron, cobalt, and lithium, or an alloy brush plating solution such as nickel-tungsten alloy, tin-zinc alloy, platinum alloy, platinum-iridium alloy, gold-iridium alloy, lithium metal alloy, and iron-lithium alloy.

[0046] In one alternative implementation, the coating thickness formed during the brushing process is from 0.1 nanometers to 20 micrometers.

[0047] This invention defines an effective range for coating thickness. At the 0.1 nanometer level, ultrathin coatings of a single atomic layer or a few atomic layers can be achieved, maximizing material savings while ensuring conductivity. An upper limit of 20 micrometers provides sufficient protection for areas under harsh conditions or with special wear resistance requirements. This range covers all needs from ultrathin films to functional thick films. By flexibly controlling parameters such as brushing time and voltage within this range, customized coating designs can be implemented for different components and locations, achieving the optimal balance between performance and cost.

[0048] In one optional embodiment, the present invention further includes pre-cleaning the gas diffusion layer, and the cleaning solution may also be hydrochloric acid, sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, propanol, etc.

[0049] In an optional embodiment, the present invention further includes an etching solution used for oxide removal, which can be used for cleaning with 0.11wt%~98wt% sulfuric acid and 0.11wt%~20wt% oxalic acid and 0.11wt%~70wt% nitric acid.

[0050] On the other hand, a proton exchange membrane water electrolyzer (PEMWE) component is provided, which is prepared by any of the above methods. The surface of the component has a discontinuously distributed noble metal or noble metal alloy coating, and the distribution position of the noble metal or noble metal alloy coating has a high spatial correlation with the distribution of rough peak regions on the surface of the component at the microscale. The noble metal or noble metal alloy coating mainly covers the rough peak regions.

[0051] The method of the present invention will be further explained and described below through specific embodiments.

[0052] Example 1 Please see Figure 1 This invention mainly uses an electroplating device to prepare a gas diffusion layer (GDL) surface coating for a PEM electrolytic cell, specifically including the following steps: Step 1: Pre-clean the gas diffusion layer by ultrasonic cleaning in acetone solution for 5-20 minutes and then drying it, ultrasonic cleaning in ethanol solution for 5-20 minutes and then drying it, and ultrasonic cleaning in deionized water for 5-20 minutes and then drying it.

[0053] Step 2: Remove the oxide layer from the gas diffusion layer by immersing it in 1wt%~38wt% hydrochloric acid at a temperature of 10℃~54℃ for 1~48h, followed by rinsing with deionized water and drying. Step 3: Prepare the surface coating of the gas diffusion layer. Place the negative electrode of the brush plating equipment into the gas diffusion layer. After immersing the positive electrode cotton head in the gold plating solution, brush the coating onto the side of the GDL where it needs to be coated. Control the temperature of the solution and the gas diffusion layer to 10℃-80℃, the brushing time to 1-3600s, the voltage to 1-10V, and the coating thickness to 0.1nm~20um (see [reference]). Figure 1 ).

[0054] Step 4: Clean the gas diffusion layer by ultrasonic cleaning in acetone solution for 5-60 minutes and then drying, ultrasonic cleaning in ethanol solution for 5-60 minutes and then drying, and ultrasonic cleaning in deionized water for 5-60 minutes and then drying.

[0055] Example 2 Please see Figure 2 This invention mainly uses an electroplating device to prepare a partitioned coating on the surface of a PEM electrolytic cell bipolar plate (BP), specifically including the following steps: Step 1: Pre-clean the bipolar plates, immerse them in acetone solution for ultrasonic cleaning for 5-20 minutes and then dry them, immerse them in ethanol solution for ultrasonic cleaning for 5-20 minutes and then dry them, immerse them in deionized water for ultrasonic cleaning for 5-20 minutes and then dry them.

[0056] Step 2: Remove the oxide layer from the bipolar plate by immersing it in 1wt%~38wt% hydrochloric acid at a temperature of 10℃~54℃ for 1~48h, followed by rinsing with deionized water and drying. Step 3: Prepare the surface coating of the bipolar plate. The negative electrode of the brush plating equipment is brought into contact with the bipolar plate. After the positive electrode cotton head is soaked in the gold plating solution, it is brushed onto the raised ridge surface of the bipolar plate flow channel. The temperature of the solution and gas diffusion layer is controlled at 10℃-80℃, the brushing time is 1-3600s, the voltage is 1-10V, and the coating thickness is 0.1nm~20um.

[0057] Step 4: Clean the bipolar plates by ultrasonic cleaning in acetone solution for 5-60 minutes and then drying, ultrasonic cleaning in ethanol solution for 5-60 minutes and then drying, and ultrasonic cleaning in deionized water for 5-60 minutes and then drying.

[0058] The preparation of the surface coating of the PEM electrolytic cell component described above is an embodiment of the present invention. In embodiment 1, a gas diffusion layer (GDL) surface coating of a PEM electrolytic cell was prepared using a brush plating device. In embodiment 2, a surface coating of the raised ridge of the flow channel of a PEM electrolytic cell bipolar plate (BP) was prepared using a brush plating device. In the comparative example, an uncoated commercial sintered titanium sheet was combined with an uncoated bipolar plate. Figure 3 These are contact resistance test diagrams for both examples and comparative models. (From...) Figure 3 As can be seen, the contact resistance of both the embodiment and the comparative example decreases with the increase of average pressure. However, the contact resistance of the embodiment is lower than that of the comparative example under all average pressures, which shows that the conductivity of the embodiment is superior.

[0059] Figure 4 The polarization curve test graphs for the examples and comparative examples are from... Figure 4 As can be seen from the data, the voltage in both the examples and the comparative examples gradually increases with the increase of current. Under the same voltage, the current density of Examples 1 and 2 is higher than that of the comparative example, resulting in the production of more hydrogen gas and improving the performance and efficiency of the electrolyzer. (Note: Since the reaction occurs at the point where the gas diffusion layer and the catalyst layer are in direct contact, the surface coating of the gas diffusion layer has a more significant impact on the performance of the electrolyzer than the surface coating of the bipolar plate.)

[0060] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for producing a coated part, characterized in that The application relates to a method for preparing a coated part, comprising the following steps: (1) electrochemical deposition on the surface of a conductive part of a proton exchange membrane water electrolysis cell by using a brush plating method; (2) wherein the brush plating is configured to form a noble metal or noble metal alloy coating layer only on a preset target area of the surface of the conductive part, the target area being a rough peak area on the surface of the conductive part in a microscale, so that when the conductive part is assembled with other parts in the proton exchange membrane water electrolysis cell, the rough peak area can form microscale point contact with other parts; (3) by controlling the plating area of the brush plating, the noble metal or noble metal alloy coating layer is preferentially covered on the rough peak area, and functional coating layers are avoided to be formed on the areas other than the rough peak area or non-contact areas on the surface of the conductive part. The conductive part is selected from at least one of a gas diffusion layer, a bipolar plate, a catalyst layer and a current collector plate. When the conductive part is a gas diffusion layer, the target area is located on the surface used for contacting the catalyst layer; and / or, When the conductive part is a bipolar plate, the target area is located on the surface of a ridge protruding in a flow channel.

2. The method of claim 1, wherein, Before the brush plating step, the surface of the conductive part is activated to remove the surface oxide layer and increase the surface energy.

3. The method of claim 2, wherein, The surface activation step comprises chemical etching of the conductive part by immersing the conductive part in an acid etching solution. The chemical etching treatment adopts a hydrochloric acid solution with a concentration of 1wt% to 38wt%, and is carried out at a temperature of 10 DEG C to 54 DEG C for 1 to 48 hours.

4. The method of claim 1, wherein, The brush plating method is implemented by the following steps:

5. The method of claim 4, wherein, The conductive part is connected to the negative pole of a power supply as a cathode; A movable plating liquid carrier adsorbing a brush plating liquid is connected to the positive pole of the power supply as an anode; 6. The method of claim 1, wherein, The anode is moved to keep contact with the target area on the surface of the conductive part and to perform brush plating. The brush plating liquid is a brush plating liquid of gold, platinum, iridium, ruthenium or an alloy thereof; The movable plating liquid carrier is a cotton head, wool, sponge, polypropylene (PP) based liquid absorbing cotton or super absorbent polymer (SAP) material. In the brush plating process, the thickness of the formed coating layer is 0.1 nanometer to 20 micrometers.

7. The method of claim 6, wherein, The part prepared by the method has a discontinuous noble metal or noble metal alloy coating layer on the surface, and the distribution position of the noble metal or noble metal alloy coating layer has high spatial correlation with the rough peak area on the surface of the part in a microscale, and the noble metal or noble metal alloy coating layer mainly covers the rough peak area. The application further relates to a proton exchange membrane water electrolysis cell comprising at least one part as described in claim 9.

8. The method of claim 6, wherein, ​ 9. A proton exchange membrane water electrolyzer component, characterized by, ​ 10. A proton exchange membrane water electrolyzer characterized by, ​

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