Electrolyzer assembly and method of making same, electrolyzer, and hydrogen production system

Abstract

The application discloses an electrolytic cell assembly, a preparation method thereof, an electrolytic cell and a hydrogen production system. The electrolytic cell assembly comprises a substrate layer and a composite coating layer located on at least one side of the substrate layer; on the side away from the substrate layer, the composite coating layer comprises a Ti layer, a TiN layer, a Ta layer, a TaN layer and a Ta' layer; and the substrate layer comprises a titanium-containing substrate layer. The application is beneficial to improving the bonding force between adjacent coating layers, reducing the contact resistance of the composite coating layer and improving the corrosion resistance of the electrolytic cell assembly (such as an anode bipolar plate).

Description

Technical Field

[0001] This application relates to the field of hydrogen production technology, specifically to electrolyzer components and their preparation methods, electrolyzers, and hydrogen production systems. Background Technology

[0002] With the increasing prevalence of hydrogen production coupled with wind and solar power plants, PEM electrolyzers (proton exchange membranes) are developing towards larger standard cubic meters (SCMs) and lower energy consumption. Currently, larger SCMs are typically achieved by increasing the active area of ​​individual cells and the number of cells in the entire cell. Increasing the active area of ​​individual cells requires fewer defects in the coating of individual plates, necessitating superior coating processes. Increasing the number of cells raises the terminal voltage. During start-up and shutdown, some components, such as the anode-side bipolar plates, experience higher voltage to ground, requiring greater corrosion resistance. Under the combined effects of acidic electrolyte solutions and high potential, titanium bipolar plates are prone to oxidation, forming low-conductivity titanium oxide, which increases interfacial contact resistance and thus energy consumption. Summary of the Invention

[0003] This application aims to at least partially address one of the technical problems in the related art. To this end, one objective of this application is to provide an electrolyzer assembly and its preparation method, an electrolyzer, and a hydrogen production system that improve corrosion resistance and reduce contact resistance.

[0004] The first aspect of this application provides an electrolytic cell assembly, including a substrate layer and a composite coating located on at least one side of the substrate layer; on the side away from the substrate layer, the composite coating includes a Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta' layer; the substrate layer includes a titanium-containing substrate layer.

[0005] This application improves the adhesion between adjacent coatings and enhances the corrosion resistance of electrolytic cell components (such as anode bipolar plates) by forming a composite coating containing Ti, TiN, Ta, TaN, and Ta' layers on the surface of the substrate layer, while also achieving lower contact resistance.

[0006] In some implementations, the composite coating satisfies at least one of the following:

[0007] (i) The thickness of the Ti layer is 50nm-150nm;

[0008] (ii) The thickness of the TiN layer is 50nm-150nm;

[0009] (iii) The thickness of the Ta layer is ≤200nm;

[0010] (iv) The thickness of the TaN layer is ≤200nm;

[0011] (v) The thickness of the Ta' layer is 300nm-800nm.

[0012] In some implementations, the electrolytic cell assembly includes an anode bipolar plate or an anode diffusion layer.

[0013] A second aspect of this application discloses a method for preparing an electrolytic cell assembly, including preparing a composite coating, wherein the preparation of the composite coating includes:

[0014] A Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta' layer are sequentially formed on at least one side of the substrate layer; the substrate layer includes a titanium-containing substrate layer.

[0015] In some embodiments, the method of sequentially forming a Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta' layer on at least one side of a substrate layer includes physical vapor deposition.

[0016] In some embodiments, the composite coating is prepared to satisfy one or more of the following:

[0017] (A) also includes plasma cleaning treatment, which includes plasma cleaning of any one of the substrate layer, Ti layer, TiN layer, Ta layer, TaN layer, and Ta' layer;

[0018] (B) Forming a Ti layer on a substrate layer using physical vapor deposition includes: bombarding the substrate with a Ti target and depositing a Ti layer;

[0019] (C) Forming a Ta layer on a TiN layer using physical vapor deposition includes: bombarding the substrate with a Ta target and depositing a Ta layer.

[0020] In some embodiments, the plasma cleaning process includes: performing a first plasma cleaning on at least one side of the substrate layer, performing a second plasma cleaning on the TiN layer, and performing a third plasma cleaning on the TaN layer.

[0021] And / or, plasma cleaning methods include one or more of glow discharge cleaning and ion cleaning.

[0022] In some embodiments, the composite coating is prepared to satisfy one or more of the following:

[0023] (a) A Ti layer is formed on the substrate layer by physical vapor deposition, with the following control parameters: temperature 200℃-250℃, bias voltage 160V-200V, and current 10A-15A.

[0024] (b) A TiN layer is formed on the Ti layer by physical vapor deposition, with the following control parameters: temperature 200℃-250℃, bias voltage 160V-200V, and current 10A-15A.

[0025] (c) A Ta layer is formed on the TiN layer by physical vapor deposition. The control parameters include: temperature 200℃-250℃, bias voltage 160V-200V, and current 10A-15A.

[0026] (d) A TaN layer was formed on the Ta layer by physical vapor deposition. The control parameters included: temperature 200℃-250℃, bias voltage 180V-200V, and current 10A-15A.

[0027] (e) A Ta' layer is formed on the TaN layer by physical vapor deposition. The control parameters include: temperature of 200℃-250℃, bias voltage of 180V-200V, and current of 10A-20A.

[0028] The third aspect of this application provides an electrolytic cell, including the electrolytic cell assembly described in the first aspect above, or including the electrolytic cell assembly obtained by the method described in the second aspect above.

[0029] The fourth aspect of this application proposes a hydrogen production system, including the electrolyzer proposed in the third aspect above.

[0030] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0031] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0032] Figure 1 The diagram shows a schematic of the preparation process of the anode bipolar plate composite coating in some embodiments of this application.

[0033] Figure 2 The images show cross-sectional and planar views of the anode bipolar plates provided in Examples 1 and 2 under an electron microscope; wherein, (a) represents a planar view of the anode bipolar plate provided in Example 2, (b) represents a planar view of the anode bipolar plate provided in Example 3, (c) represents a cross-sectional view of the anode bipolar plate provided in Example 2, and (d) represents a cross-sectional view of the anode bipolar plate provided in Example 3.

[0034] Figure 3 The diagram shows the constant potential test results of the anode bipolar plates provided for each embodiment and comparative example; where "bol" indicates the test result of the coating without aging; and "eol" indicates the test result of the coating after aging. Detailed Implementation

[0035] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0036] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0037] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this application.

[0038] In this application, the terms "comprising" or "including" are open-ended expressions, meaning they include the content specified in this application but do not exclude other aspects.

[0039] Currently, the anode-side bipolar plate coating of PEM electrolytic cells is still commercially available using Pt electroplating, but its high price hinders the marketization of PEM electrolytic cells. Therefore, developing non-precious metal coatings is of great significance.

[0040] Therefore, the first aspect of the present application provides an electrolytic cell assembly, including a substrate layer and a composite coating located on at least one side of the substrate layer;

[0041] On the side away from the substrate layer, the composite coating includes a Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta' layer;

[0042] The substrate layer includes a titanium-containing substrate layer.

[0043] In this application, "Ta' layer" is used to distinguish it from the Ta layer formed on the TiN layer; both the Ta layer and the Ta' layer contain the element Ta (tantalum).

[0044] The embodiments of this application form a composite coating containing Ti, TiN, Ta, TaN, and Ta' layers on the surface of the substrate layer, which helps to improve the bonding force between adjacent coatings, reduce the contact resistance of the composite coating, and improve the corrosion resistance of electrolytic cell components (such as anode bipolar plates).

[0045] By forming a Ti layer on the substrate layer, since the substrate layer includes a titanium-containing substrate layer, and both the Ti layer and the titanium-containing substrate layer contain titanium, the types of interatomic interactions and bonding strengths are more compatible, and the crystal structures and parameters are the same or similar. This facilitates better coating growth on the substrate surface, reduces defects at the interface, and thus improves the adhesion between the titanium-containing substrate layer and the Ti layer. By forming a TiN layer on the Ti layer, a strong adhesion can be formed with the Ti layer, further reducing the surface roughness of the substrate layer and promoting a high adhesion of the Ta layer on the TiN layer. By forming a TaN layer on the Ta layer, the TaN layer and the Ta layer, which contain the same Ta element, can form a high adhesion. The TaN layer is also more conducive to the growth of the Ta' layer, forming a cubic crystal structure Ta' layer with good density and stability. The Ta' layer, as the external contact surface of the composite coating (such as in contact with acidic environments), exhibits good corrosion resistance, thereby improving the corrosion resistance of the composite coating. In this embodiment, by optimizing the design of each coating layer, a composite coating with high adhesion is formed, which helps to improve the problem of high contact resistance of the composite coating; in addition, by forming intermediate coatings such as TiN layer and TaN layer, which have high conductivity, it is beneficial to further reduce the contact resistance of the composite coating.

[0046] In summary, the embodiments of this application provide an electrolytic cell assembly with a corrosion-resistant composite coating having low contact resistance.

[0047] In some embodiments of this application, the composite coating satisfies at least one of the following:

[0048] (i) The thickness of the Ti layer is 50nm-150nm;

[0049] (ii) The thickness of the TiN layer is 50nm-150nm;

[0050] (iii) The thickness of the Ta layer is ≤200nm;

[0051] (iv) The thickness of the TaN layer is ≤200nm;

[0052] (v) The thickness of the Ta' layer is 300nm-800nm.

[0053] In this embodiment, the thickness of the Ti layer is 50nm-150nm, which is beneficial for covering defects on the surface of the titanium-containing substrate, improving the surface roughness of the titanium-containing substrate, and improving the adhesion of the TiN layer on the titanium-containing substrate.

[0054] As an example, the thickness of the Ti layer is 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, etc.

[0055] In this embodiment, the thickness of the TiN layer is 50nm-150nm, which enables it to form a strong bond with the Ti layer, further improving the surface roughness of the titanium-containing substrate layer and enhancing the adhesion of the subsequent Ta layer. Furthermore, the TiN layer thickness meeting the above conditions helps to better reduce the contact resistance of the composite coating.

[0056] As an example, the thickness of the TiN layer is 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, etc.

[0057] In this embodiment, the thickness of the Ta layer is ≤200nm, which helps to improve the bonding force between the TiN layer and the TaN layer, that is, to improve the adhesion ability of the subsequent TaN layer.

[0058] As an example, the thickness of the Ta layer is 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, etc.

[0059] In this embodiment, the thickness of the TaN layer is ≤200nm, which can form a good bond with the Ta layer and help reduce the contact resistance of the composite coating; in addition, it is beneficial to the subsequent growth of the Ta layer and promotes the growth of the Ta layer with a cubic crystal structure.

[0060] As an example, the thickness of the TaN layer is 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, etc.

[0061] In this embodiment, the thickness of the Ta' layer is 300nm-800nm, which allows it to adhere firmly to the TaN layer and provide better corrosion resistance.

[0062] As an example, the thickness of the Ta' layer is 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, etc.

[0063] In some embodiments of this application, the composite coating satisfies at least one of the following:

[0064] (a) The thickness of the TiN layer is 50nm-100nm;

[0065] (b) The thickness of the Ta layer is 100nm-200nm;

[0066] (c) The thickness of the TaN layer is 100nm-200nm;

[0067] (d) The thickness of the Ta layer is 300nm-500nm.

[0068] In this embodiment, the thickness of the TiN layer meets the above conditions, enabling it to form a stronger bond with the Ti layer, further improving the surface roughness of the titanium-containing substrate layer and enhancing the adhesion of the subsequent Ta layer. Furthermore, the TiN layer thickness meeting the above conditions helps to further reduce the contact resistance of the composite coating.

[0069] In this embodiment, the thickness of the Ta layer meets the above conditions, which is beneficial to further improve the bonding force between the TiN layer and the TaN layer, that is, to improve the adhesion ability of the subsequent TaN layer.

[0070] In this embodiment, the thickness of the TaN layer meets the above conditions, enabling it to form a better bond with the Ta layer and further reducing the contact resistance of the composite coating; in addition, it is more conducive to the subsequent growth of the Ta layer and promotes the growth of the Ta layer with a cubic crystal structure.

[0071] In this embodiment, the thickness of the Ta' layer meets the above conditions, enabling it to adhere firmly to the TaN layer and further enhance its corrosion resistance.

[0072] In some embodiments of this application, the electrolytic cell assembly includes an anode bipolar plate or an anode diffusion layer.

[0073] In this embodiment, the anode bipolar plate has a meaning known in the art, being a conductive layer located on the anode side, typically with a flow field design on its surface. The anode bipolar plate serves to conduct current and remove oxygen generated at the anode.

[0074] In this embodiment, the anode diffusion layer has a meaning known in the art, typically a conductive layer located between the bipolar plate and the anode catalyst layer. The anode diffusion layer serves to distribute reactant gases to the catalyst layer, exhaust oxygen, and conduct current.

[0075] Furthermore, in the case where the electrolytic cell assembly is an anode bipolar plate, the titanium-containing substrate layer includes a titanium bipolar plate substrate.

[0076] Furthermore, in the case where the electrolytic cell assembly is an anode diffusion layer, the titanium-containing substrate layer includes one or more of titanium fiber felt, titanium porous plate, and titanium mesh.

[0077] A second aspect of this application provides a method for preparing an electrolytic cell assembly, including preparing a composite coating, wherein the preparation of the composite coating includes:

[0078] A Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta layer are sequentially formed on at least one side of the substrate layer; the substrate layer includes a titanium-containing substrate layer.

[0079] This application embodiment forms a Ti layer on a substrate layer. Since the substrate layer includes a titanium-containing substrate layer, and both the Ti layer and the titanium-containing substrate layer contain titanium, the types of interatomic interactions and bonding strengths are more compatible, and the crystal structures and parameters are the same or similar. This facilitates better coating growth on the substrate surface, reduces interface defects, and thus improves the adhesion between the titanium-containing substrate layer and the Ti layer. Forming a TiN layer on the Ti layer allows for strong adhesion, further reducing the surface roughness of the substrate layer and promoting higher adhesion of the Ta layer on the TiN layer. Forming a TaN layer on the Ta layer, with the same Ta element as the Ta layer, allows for high adhesion. The TaN layer also promotes the growth of the Ta' layer, forming a cubic crystal structure with good density and stability. The Ta' layer, as the external contact surface of the composite coating (e.g., in contact with acidic environments), exhibits good corrosion resistance, thereby improving the corrosion resistance of the composite coating. In this embodiment, by optimizing the design of each coating layer, a composite coating with high adhesion is formed, which helps to improve the problem of high contact resistance of the composite coating; in addition, by forming intermediate coatings such as TiN layer and TaN layer, which have high conductivity, it is beneficial to further reduce the contact resistance of the composite coating.

[0080] In summary, the embodiments of this application provide an electrolytic cell assembly with a corrosion-resistant composite coating having low contact resistance.

[0081] In some embodiments of this application, the method of sequentially forming a Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta layer on at least one side of a substrate layer includes physical vapor deposition.

[0082] Currently, the electroplating of Pt layers commonly used in existing technologies has relatively poor coating density, and the electroplating solution is prone to environmental pollution. This application employs physical vapor deposition (PVD) under vacuum or low-pressure conditions, resulting in stronger adhesion between the composite coating and the substrate, as well as stronger adhesion between the individual layers within the composite coating. This facilitates the formation of a composite coating with stronger adhesion and higher density.

[0083] In some embodiments of this application, the composite coating is prepared to satisfy one or more of the following:

[0084] (A) also includes plasma cleaning treatment, which includes plasma cleaning of any one of the substrate layer, Ti layer, TiN layer, Ta layer, TaN layer, and Ta layer;

[0085] (B) Forming a Ti layer on a substrate layer using physical vapor deposition includes: bombarding the substrate with a Ti target and depositing a Ti layer;

[0086] (C) Forming a Ta layer on a TiN layer using physical vapor deposition includes: bombarding the substrate with a Ta target and depositing a Ta layer.

[0087] In this embodiment of the application, the preparation of the composite coating combines physical vapor deposition with plasma cleaning. Plasma cleaning is performed on any one of the substrate layer, Ti layer, TiN layer, Ta layer, TaN layer, and Ta layer to remove surface contaminants, soft structures, and other substances, thereby promoting better adhesion. After plasma cleaning, the next coating is deposited using physical vapor deposition.

[0088] In this embodiment of the application, during the process of forming a Ti layer on the substrate layer, the Ti target can be turned on first to bombard the surface of the substrate layer, which can clean the surface of the substrate layer. In addition, by bombarding the substrate layer with high-energy particles, Ti high-energy ions can penetrate the surface of the substrate layer and enter the substrate layer matrix to form a thin "underlayment". This material can serve as a transition layer for subsequent Ti plating, further enhancing the adhesion between the Ti plating layer and the substrate layer.

[0089] In this embodiment, during the formation of a Ta layer on the TiN layer, a Ta target can be activated first to bombard the surface of the TiN layer, which can clean the surface of the TiN layer. In addition, by bombarding the substrate layer with high-energy particles, Ta high-energy ions can penetrate the surface of the substrate layer and enter the TiN layer matrix to form a thin "underlayment". This material can serve as a transition layer for subsequent Ta plating, further enhancing the adhesion between the Ta plating layer and the TiN layer.

[0090] In some embodiments of this application, plasma cleaning includes: performing a first plasma cleaning on at least one side of the substrate layer, performing a second plasma cleaning on the TiN layer, and performing a third plasma cleaning on the TaN layer; and / or, the plasma cleaning method includes one or more of glow discharge cleaning and ion cleaning.

[0091] In this embodiment, plasma cleaning of the substrate layer helps to remove contaminants, soft structures, and other substances from the surface of the substrate layer, as well as the oxide layer, thereby improving the adhesion between the Ti layer and the substrate layer.

[0092] In this embodiment, plasma cleaning of the TiN layer removes soft surface structures and other substances formed during the formation of the TiN layer, thereby further improving the bonding force between the Ta layer and the TiN layer.

[0093] By sequentially forming Ti, TiN, Ta, and TaN layers on a substrate layer, the overall coating thickness gradually increases, potentially increasing the number of intermediate defect sites and porosity. Furthermore, a columnar crystal structure may also form. In this embodiment, plasma cleaning of the TaN layer further inhibits the continuous growth of defects, improving the adhesion between the Ta' and TaN layers and promoting the formation of the Ta' layer with a cubic crystal structure, thereby enhancing the corrosion resistance of the composite coating.

[0094] In this embodiment, the plasma cleaning method includes one or more of glow discharge cleaning and ion cleaning. Glow discharge cleaning, ion cleaning, or a combination of both can be used.

[0095] Furthermore, the plasma cleaning process includes: first performing glow discharge cleaning, and then performing ion cleaning.

[0096] Because titanium-containing substrates are relatively soft, the sputtering yield of titanium is relatively high, leading to the easy sputtering of Ti atoms on the substrate surface, resulting in a dense and uneven rough surface. This application's embodiments utilize a combination of glow discharge cleaning and ion cleaning to mitigate the titanium sputtering problem and improve the plasma cleaning effect.

[0097] In some embodiments of this application, the control parameters in the glow discharge cleaning step include: temperature of 200℃-250℃, vacuum degree of 0.2Pa-2.0Pa, bias voltage of 500V-800V, and time of 5min-20min.

[0098] In this embodiment, by adjusting various parameters to meet the above conditions, the cleaning effect can be fully utilized, the degree of damage to the cleaned surface can be reduced, and the adhesion between adjacent coatings can be improved.

[0099] In some embodiments of this application, the control parameters in the ion cleaning step include: temperature of 200℃-250℃, vacuum degree of 0.2Pa-2.0Pa, bias voltage of 500V-800V, and time of 5min-20min.

[0100] In this embodiment, by adjusting various parameters to meet the above conditions, the cleaning effect can be fully utilized, the degree of damage to the cleaned surface can be reduced, and the adhesion between adjacent coatings can be improved.

[0101] In some embodiments of this application, the ion cleaning step includes:

[0102] At least one side of the substrate layer is subjected to plasma cleaning once, with glow discharge cleaning time of 15 min-20 min and ion cleaning time of 15 min-20 min;

[0103] The TiN layer was subjected to secondary plasma cleaning, with glow discharge cleaning for 5-15 minutes and ion cleaning for 5-15 minutes.

[0104] The TaN layer was subjected to three plasma cleaning processes: glow discharge cleaning for 5-15 minutes and ion cleaning for 5-15 minutes.

[0105] In this embodiment, by optimizing the cleaning time, it is beneficial to further reduce the degree of damage to the cleaning surface and further improve the adhesion between adjacent coatings.

[0106] In some embodiments of this application, the plasma cleaning method includes the following steps:

[0107] The vacuum level in the working chamber (such as the PVD chamber) is evacuated to 5 × 10⁻⁶. -3 When the pressure is below 1 Pa, argon gas is introduced.

[0108] Raise the temperature to 200℃-250℃ and adjust the argon flow rate until the vacuum level in the PVD chamber is 0.2Pa-2.0Pa;

[0109] Set the bias voltage to 500V-800V and perform glow discharge cleaning;

[0110] Maintain the above temperature and vacuum level; turn on the ion source power supply, set the bias voltage to 500V-800V, and perform ion cleaning.

[0111] In some embodiments of this application, the composite coating is prepared to satisfy one or more of the following:

[0112] (a) A Ti layer is formed on the substrate layer by physical vapor deposition, with the following control parameters: temperature 200℃-250℃, bias voltage 160V-200V, and current 10A-15A.

[0113] (b) A TiN layer is formed on the Ti layer by physical vapor deposition, with the following control parameters: temperature 200℃-250℃, bias voltage 160V-200V, and current 10A-15A.

[0114] (c) A Ta layer is formed on the TiN layer by physical vapor deposition. The control parameters include: temperature 200℃-250℃, bias voltage 160V-200V, and current 10A-15A.

[0115] (d) A TaN layer was formed on the Ta layer by physical vapor deposition. The control parameters included: temperature 200℃-250℃, bias voltage 180V-200V, and current 10A-15A.

[0116] (e) A Ta' layer is formed on the TaN layer by physical vapor deposition. The control parameters include: temperature of 200℃-250℃, bias voltage of 180V-200V, and current of 10A-20A.

[0117] In the embodiments of this application, by controlling parameters such as temperature, bias voltage, and current during the physical vapor deposition coating process, it is beneficial to obtain higher interlayer bonding force and reduce contact resistance; in addition, it is beneficial to form a more stable Ta' layer.

[0118] As an example, if the bias voltage meets the above conditions, it is beneficial to obtain high-energy particles for vapor deposition, improve the adhesion of the coating, and reduce the contact resistance.

[0119] As an example, when the temperature meets the above conditions, it can play a role in sintering and dispersing, reduce the increase of defects, form a continuous and stable coating structure, and reduce contact resistance.

[0120] In some embodiments of this application, the steps for preparing the composite coating include a pretreatment step, a plasma cleaning step, and a coating step, such as... Figure 1 As shown, the specific steps include:

[0121] Provide a substrate layer, such as a bare titanium plate for an anode bipolar plate;

[0122] Pre-treat the substrate layer, such as by cleaning with chemical cleaning agents;

[0123] The pretreated substrate layer is subjected to a plasma cleaning process, such as glow discharge cleaning and ion cleaning.

[0124] A Ti layer is formed on the substrate layer after plasma cleaning;

[0125] A TiN layer is formed on the Ti layer;

[0126] The TiN layer is subjected to secondary plasma cleaning, such as glow discharge cleaning and ion cleaning.

[0127] A Ta layer is formed on the TiN layer;

[0128] A TaN layer is formed on the Ta layer;

[0129] The TaN layer is subjected to three plasma cleaning processes, including glow discharge cleaning and ion cleaning.

[0130] A Ta layer is formed on top of the TaN layer.

[0131] In some embodiments of this application, the steps for preparing the composite coating include a pretreatment step, a plasma cleaning step, and a coating step, wherein:

[0132] Plasma cleaning steps:

[0133] The vacuum level in the PVD chamber was evacuated to 5 × 10⁻⁵. -3 When the pressure is below 1 Pa, argon gas is introduced.

[0134] Raise the temperature to 200℃-250℃ and adjust the argon flow rate until the vacuum level in the PVD chamber is 0.2Pa-2.0Pa;

[0135] Set the bias voltage to 500V-800V and the glow discharge cleaning time to 15min-20min;

[0136] Maintain constant vacuum and temperature, turn on the ion source power supply, set the bias voltage to 500V-800V, and the ion cleaning time to 15min-20min.

[0137] Coating steps:

[0138] Adjust the argon flow rate to a vacuum of 0.1Pa-1.0Pa, set the bias voltage to 160V-200V, turn on the Ti target power supply, bombard the substrate with 20A-25A for 5min-10min, and then adjust the current to 10A-15A to start depositing the Ti layer.

[0139] Turn on the nitrogen gas, adjust the vacuum level to 0.1Pa-1.0Pa, and maintain the Ti target current at 10A-15A to begin depositing the TiN layer;

[0140] Turn off the Ti target power supply and close the nitrogen valve before proceeding with the plasma cleaning step.

[0141] Turn on the Ta target power supply and bombard the substrate with 20A-25A for 5-10 minutes. Then adjust the current to 10A-15A and start depositing the Ta layer.

[0142] Open the nitrogen valve, adjust the vacuum level to 0.1Pa-1.0Pa, set the bias voltage to 180V-200V, keep other parameters unchanged, and start depositing the TaN layer;

[0143] Turn off the Ta target power supply and close the nitrogen valve; proceed with the plasma cleaning step.

[0144] Turn on the Ta target, adjust the current to 10A-20A, and begin plating the Ta layer.

[0145] In some embodiments of this application, the preparation of the composite coating further includes a pretreatment step; after pretreatment of the substrate layer, plasma cleaning and coating are then performed.

[0146] Further preprocessing steps include:

[0147] The substrate is ultrasonically cleaned in isopropanol solution at room temperature for 5-10 minutes; then it is soaked in 5wt%-30wt% oxalic acid solution at 60℃-80℃ for 5-60 minutes; finally, it is repeatedly ultrasonically cleaned and soaked in deionized water until the cleaning solution is neutral.

[0148] The third aspect of this application provides an electrolytic cell, including the electrolytic cell assembly proposed in the first aspect or the electrolytic cell assembly obtained in the preparation aspect proposed in the second aspect.

[0149] In this embodiment, the electrolytic cell includes the electrolytic cell assembly described above, and has the beneficial effects of the electrolytic cell assembly described above, which will not be repeated here.

[0150] The fourth aspect of this application provides a hydrogen production system, including the electrolyzer described in the third aspect above.

[0151] In this embodiment, the hydrogen production system includes the electrolyzer described above, and has the beneficial effects of the electrolyzer described above, which will not be repeated here.

[0152] The following will explain the solution of this application with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0153] [Preparation of the Anode Bipolar Plate]

[0154] Example 1

[0155] (1) Cut the substrate into 5cm×5cm pieces, place them in isopropanol solution and ultrasonically clean them at room temperature for 5min, then use 5wt% oxalic acid solution and soak them at 80℃ for 20min, and then repeatedly ultrasonically clean and soak them in deionized water until the cleaning solution is neutral.

[0156] (2) Place the substrate in the PVD equipment and wait for the vacuum to reach 5.10. -3 At Pa, begin heating the chamber and open the argon gas valve to introduce argon gas. When the temperature reaches 200℃, adjust the argon gas flow rate to a vacuum level of 1.5Pa. Set the bias power supply to 800V and begin glow discharge cleaning for 15 minutes. Turn on the ion source power supply, set the voltage to 600V, and begin ion cleaning for 15 minutes.

[0157] (3) Adjust the argon flow rate to make the vacuum degree 0.5 Pa, turn on the Ti target, set the current to 15 A, bombard the base for 5 min, then adjust the current to 12 A to start the Ti layer deposition. After 20 min, the Ti layer thickness is 100 nm. At the same time, open the nitrogen and argon valves, with a gas volume ratio of 1:1, to ensure the deposition pressure is 0.5 Pa. Set the Ti target current to 12 A and start the TiN layer deposition. The time is 30 min and the TiN layer thickness is 150 nm.

[0158] (4) Turn off the Ti target power supply and nitrogen valve, raise the temperature to 250℃, adjust the argon flow rate to a pressure of 0.5Pa, turn on the Ta target power supply, set the current to 12A, change the bias voltage to 900V, start the Ta layer deposition, the time is 30min, the Ta layer thickness is 150nm. Then simultaneously open the nitrogen and argon valves, the gas volume ratio is 1:1, ensure the deposition pressure is 0.5Pa, set the Ta target current to 12A, keep the bias voltage at 900V, start the TaN layer deposition, the deposition time is 30min, the TaN layer thickness is 100nm.

[0159] (5) Then close the nitrogen valve, adjust the argon flow rate to a pressure of 0.5 Pa, and begin depositing a cubic stable Ta layer. The deposition time is 60 min, and the Ta layer thickness is 300 nm. After completion, close all load and gas valves, turn off the heating, and allow the sample to cool with the furnace to obtain the sample of Example 1. The composite coating composition is Ti / TiN / Ta / TaN / Ta.

[0160] Example 2

[0161] (1) Cut the bare titanium plate into 5cm×5cm pieces, put it into isopropanol solution and ultrasonically clean it at room temperature for 5min, then use 5wt% oxalic acid solution and soak it at 80℃ for 20min, and then repeatedly ultrasonically clean and soak it in deionized water until the cleaning solution is neutral.

[0162] (2) Place the substrate in the PVD equipment and wait for the vacuum to reach 5.10. -3 At Pa, begin heating the chamber and open the argon gas valve to introduce argon gas. When the temperature reaches 200℃, adjust the argon gas flow rate to a vacuum level of 1.5Pa. Set the bias power supply to 800V and begin glow discharge cleaning for 15 minutes. Turn on the ion source power supply, set the voltage to 600V, and begin ion cleaning for 15 minutes.

[0163] (3) Adjust the argon flow rate to make the vacuum degree 0.5 Pa, turn on the Ti target, set the current to 15 A, bombard the base for 5 min, then adjust the current to 12 A to start the Ti layer deposition. After 20 min, the Ti layer thickness is 100 nm. At the same time, open the nitrogen and argon valves, with a gas volume ratio of 1:1, to ensure the deposition pressure is 0.5 Pa. Set the Ti target current to 12 A and start the TiN layer deposition. The time is 30 min and the TiN layer thickness is 150 nm.

[0164] (4) Turn off the Ti target power supply and nitrogen valve, and repeat step (2).

[0165] (5) Raise the temperature to 250℃, adjust the argon flow rate to a pressure of 0.5Pa, turn on the Ta target power supply, set the current to 12A, change the bias voltage to 900V, start the Ta layer deposition, the time is 30min, the Ta layer thickness is 150nm, then simultaneously open the nitrogen and argon valves, the gas volume ratio is 1:1, ensure the deposition pressure is 0.5Pa, set the Ta target current to 12A, keep the bias voltage at 900V, start the TaN layer deposition, the deposition time is 30min, the TaN layer thickness is 100nm.

[0166] (6) Close the nitrogen valve and repeat step (2).

[0167] (7) Adjust the argon flow rate to a pressure of 0.5 Pa, and begin depositing a cubic stable Ta layer. The deposition time is 60 min, and the Ta layer thickness is 300 nm. After the deposition is completed, close all loads and gas valves, turn off the heating, and allow the sample to cool with the furnace to obtain the sample of Example 2. The composite coating composition is Ti / TiN / Ta / TaN / Ta.

[0168] Example 3

[0169] An anode bipolar plate with a composite coating was prepared using the method of Example 2, the difference being that the outermost Ta coating thickness was 600 nm, resulting in the sample of Example 3, with the composite coating composition being Ti / TiN / Ta / TaN / Ta.

[0170] Example 4

[0171] An anode bipolar plate with a composite coating was prepared using the method of Example 2, the difference being that the cleaning step of step (2) was repeated between the preparation of the Ti layer and the TiN layer, and the cleaning step of step (2) was repeated between the preparation of the Ta layer and the TaN layer; the TiN layer and the TaN layer were not cleaned, resulting in the sample of Example 4, with the composite coating composition being Ti / TiN / Ta / TaN / Ta.

[0172] Comparative Example 1

[0173] Bare titanium plates were used as anode bipolar plates, and no composite coating was prepared.

[0174] Comparative Example 2

[0175] (1) Cut the bare titanium plate into 5cm×5cm pieces, put it into isopropanol solution and ultrasonically clean it at room temperature for 5min, then use 5wt% oxalic acid solution and soak it at 80℃ for 20min, and then repeatedly ultrasonically clean and soak it in deionized water until the cleaning solution is neutral.

[0176] (2) Place the substrate in the PVD equipment and wait for the vacuum to reach 5.10. -3 At Pa, begin heating the chamber and open the argon gas valve to introduce argon gas. When the temperature reaches 200℃, adjust the argon gas flow rate to a vacuum level of 1.5Pa. Set the bias power supply to 800V and begin glow discharge cleaning for 15 minutes. Turn on the ion source power supply, set the voltage to 600V, and begin ion cleaning for 15 minutes.

[0177] (3) Adjust the argon flow rate to make the vacuum degree 0.5 Pa, turn on the Ti target, set the current to 15 A, bombard the base for 5 min, then adjust the current to 12 A to start the Ti layer deposition. After 20 min, the Ti layer thickness is 100 nm. At the same time, open the nitrogen and argon valves, with a gas volume ratio of 1:1, to ensure the deposition pressure is 0.5 Pa. Set the Ti target current to 12 A and start the TiN layer deposition. The time is 140 min and the TiN layer thickness is 700 nm.

[0178] After completion, all load and gas valves were closed, heating was turned off, and the sample was allowed to cool with the furnace to obtain Comparative Example 2 sample, with a coating composition of Ti / TiN.

[0179] Comparative Example 3

[0180] (1) Cut the bare titanium plate into 5cm×5cm pieces, put it into isopropanol solution and ultrasonically clean it at room temperature for 5min, then use 5wt% oxalic acid solution and soak it at 80℃ for 20min, and then repeatedly ultrasonically clean and soak it in deionized water until the cleaning solution is neutral.

[0181] (2) Place the substrate in the PVD equipment and wait for the vacuum to reach 5.10. -3 At Pa, begin heating the chamber and open the argon gas valve to introduce argon gas. When the temperature reaches 200℃, adjust the argon gas flow rate to a vacuum level of 1.5Pa. Set the bias power supply to 800V and begin glow discharge cleaning for 15 minutes. Turn on the ion source power supply, set the voltage to 600V, and begin ion cleaning for 15 minutes.

[0182] (3) Adjust the argon flow rate to achieve a vacuum of 0.5 Pa, turn on the Ta target, set the current to 15 A, and bombard the substrate for 5 minutes. Then adjust the current to 12 A to begin depositing the Ta layer. After 20 minutes, the Ta layer thickness is 100 nm.

[0183] (4) Raise the temperature to 250℃, adjust the argon flow rate to a pressure of 0.5Pa, turn on the Ta target power supply, and then simultaneously open the nitrogen and argon valves with a gas volume ratio of 1:1 to ensure a coating pressure of 0.5Pa. Set the Ta target current to 12A and maintain the bias voltage at 900V. Start coating the TaN layer. The coating time is 30min and the TaN layer thickness is 100nm.

[0184] (5) Close the nitrogen valve and repeat step (2).

[0185] (6) Adjust the argon flow rate to a pressure of 0.5 Pa, and begin depositing a cubic stable Ta layer. The deposition time is 120 min, and the Ta layer thickness is 600 nm. After the deposition is completed, close all loads and gas valves, turn off the heating, and allow the sample to cool with the furnace to obtain Comparative Example 3 sample, with a coating composition of Ta / TaN / Ta.

[0186] Comparative Example 4

[0187] An anode bipolar plate with a composite coating was prepared using the method of Example 2, except that the thickness of the TiN coating was changed to 100 nm, and a 600 nm Ta coating was directly deposited on the outside of the TiN coating to obtain the Comparative Example 4 sample, with a coating composition of Ti / TiN / Ta.

[0188] [Performance Testing]

[0189] I. Testing Methods

[0190] 1. Contact resistance test

[0191] The above-described embodiments and comparative samples were each tested independently. Pressure was applied using a universal testing machine (Jinan Zhongluchang Testing Machine Manufacturing Co., Ltd., WDW-10M model, loading speed 0.02 MPa / s, each target pressure value stabilized for 30 seconds), current was applied using a DC power supply (ITECH, IT6722A), and voltage was measured using a multimeter (FLUKE, 8845A). Carbon paper was placed between the electrode plates and the sample during testing. The contact resistance was calculated based on the measured current and voltage.

[0192] 2. Constant Potential Test

[0193] After accelerated corrosion (electrolyte 0.5M H₂SO₄, 60℃, working electrode coating sample, exposed area 1cm²), 2 The reference electrode was a saturated calomel electrode, and the counter electrode was a platinum sheet. Cyclic potentials ranged from -0.2V to 1.9V (vs. RE), with a scan rate of 50mV / s and 20 cycles. The results of the potentiostatic test at 1.9V were obtained (Gamry, Energylab).

[0194] II. Test Results

[0195] The test results are shown in Table 1. Figure 2 and Figure 3 As shown.

[0196] 1. Table 1 shows the contact resistivity of each sample at 2MPa (the pressure was applied using a universal testing machine (Jinan Zhongluchang Testing Machine Manufacturing Co., Ltd., WDW-10M model, loading speed 0.02MPa / s, slowly increasing the pressure to 2MPa).

[0197] Table 1

[0198]

[0199] As shown in Table 1, Examples 1-4 of this application achieve lower resistivity by preparing Ti / TiN / Ta / TaN / Ta on the surface of a titanium plate. Furthermore, as shown in Examples 2 and 4, combining this with plasma cleaning further reduces resistivity; in particular, optimizing the plasma cleaning location leads to even lower resistivity, as shown in Example 2.

[0200] 2. For example Figure 2 As can be seen from the cross-sectional images in (c) and (d) of Example 2, the composite coating prepared by combining vapor deposition with plasma cleaning exhibits reduced delamination; and according to Figure 2 As shown in the planar diagrams (a) and (b), the addition of the plasma cleaning step in Example 2 resulted in a denser surface and smaller particle size in the composite coating. Therefore, the method of combining vapor deposition with plasma cleaning to prepare the composite coating is beneficial for improving its corrosion resistance.

[0201] 3. For example Figure 3 As shown, overall, applying a coating improves corrosion resistance compared to not applying a coating. The composite coating provided in this application embodiment achieves better corrosion resistance than the comparative example, especially when combined with plasma cleaning technology, which further enhances corrosion resistance. Example 3 has a thicker Ta coating than Example 2, resulting in lower current before and after accelerated corrosion. Compared to Example 1, Example 2's coating includes an interlayer cleaning step, resulting in fewer continuous defects and thus greater corrosion resistance; after accelerated corrosion, it exhibits lower current at the same voltage.

[0202] In summary, the composite coating provided in this application embodiment is advantageous for achieving high corrosion resistance while also possessing low contact resistance.

[0203] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An electrolytic cell assembly, characterized in that, It includes a substrate layer and a composite coating located on at least one side of the substrate layer; On the side away from the substrate layer, the composite coating includes a Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta' layer; The substrate layer includes a titanium-containing substrate layer.

2. The electrolytic cell assembly according to claim 1, characterized in that, The composite coating satisfies at least one of the following: (i) The thickness of the Ti layer is 50nm-150nm; (ii) The thickness of the TiN layer is 50nm-150nm; (iii) The thickness of the Ta layer is ≤200nm; (iv) The thickness of the TaN layer is ≤200nm; (v) The thickness of the Ta' layer is 300nm-800nm.

3. The electrolytic cell assembly according to claim 1, characterized in that, The electrolytic cell assembly includes an anode bipolar plate or an anode diffusion layer.

4. A method for preparing an electrolytic cell assembly, characterized in that, The process includes preparing a composite coating, wherein the preparation of the composite coating includes: A Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta' layer are sequentially formed on at least one side of the substrate layer; the substrate layer includes a titanium-containing substrate layer.

5. The method according to claim 4, characterized in that, The method for sequentially forming a Ti layer, a TiN layer, a Ta layer, a TaN layer, and a Ta' layer on at least one side of a substrate layer includes physical vapor deposition.

6. The method according to claim 5, characterized in that, The preparation of the composite coating satisfies one or more of the following: (A) also includes plasma cleaning, wherein the plasma cleaning includes plasma cleaning of any one of the substrate layer, Ti layer, TiN layer, Ta layer, TaN layer, and Ta' layer; (B) Forming the Ti layer on the substrate layer using physical vapor deposition includes: bombarding the substrate with a Ti target and depositing a Ti layer; (C) Forming the Ta layer on the TiN layer using physical vapor deposition includes: bombarding the substrate with a Ta target and depositing a Ta layer.

7. The method according to claim 6, characterized in that, The plasma cleaning process includes: performing a first plasma cleaning on at least one side of the substrate layer, performing a second plasma cleaning on the TiN layer, and performing a third plasma cleaning on the TaN layer. And / or, the plasma cleaning process includes one or more of glow discharge cleaning and ion cleaning.

8. The method according to any one of claims 5 to 7, characterized in that, The preparation of the composite coating satisfies one or more of the following: (a) The Ti layer is formed on the substrate layer by physical vapor deposition, and the control parameters include: temperature of 200℃-250℃, bias voltage of 160V-200V, and current of 10A-15A. (b) The TiN layer is formed on the Ti layer by physical vapor deposition, and the control parameters include: temperature of 200℃-250℃, bias voltage of 160V-200V, and current of 10A-15A. (c) The Ta layer is formed on the TiN layer by physical vapor deposition, and the control parameters include: temperature of 200℃-250℃, bias voltage of 160V-200V, and current of 10A-15A. (d) The TaN layer is formed on the Ta layer by physical vapor deposition, and the control parameters include: temperature of 200℃-250℃, bias voltage of 180V-200V, and current of 10A-15A. (e) The Ta' layer is formed on the TaN layer by physical vapor deposition, with the following control parameters: temperature 200℃-250℃, bias voltage 180V-200V, and current 10A-20A.

9. An electrolytic cell, characterized in that, The electrolytic cell assembly includes any one of claims 1 to 3, or the electrolytic cell assembly obtained by the method of any one of claims 4 to 8.

10. A hydrogen production system, characterized in that, Includes the electrolytic cell as described in claim 9.

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