Aluminum-based metal bipolar plate and its preparation method and application

Abstract

The present application relates to the technical field of fuel cells, and particularly relates to an aluminum-based metal bipolar plate and a preparation method and application thereof. The aluminum-based metal bipolar plate comprises: an aluminum-based substrate comprising industrial pure aluminum or an aluminum alloy; a modified layer formed on the surface of the aluminum-based substrate and formed by ion implantation on the aluminum-based substrate; the implanted element of the ion implantation comprises one or more of N, Ti, Cr, Ta, Nb and Ni; and a functional coating layer formed on the surface of the modified layer and formed by magnetron sputtering; the material of the functional coating layer comprises a single layer or a multi-layer structure formed by one or more of Ti, Cr, Ta, Nb, Ni, Al, nitrides thereof and carbonitrides thereof. The aluminum-based metal bipolar plate has advantages in terms of light weight, cost control, thermal conductivity and electrical conductivity, can significantly improve the overall corrosion resistance, improve the quality of the bipolar plate, reduce the cost, and has good prospects for large-scale production and application.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to an aluminum-based metal bipolar plate, its preparation method, and its application. Background Technology

[0002] A fuel cell is a device that directly converts the chemical energy contained in fuel (such as hydrogen, natural gas, etc.) and oxidant (such as air, oxygen) into electrical energy through an electrochemical reaction. It features high energy conversion efficiency and environmental friendliness. Proton exchange membrane fuel cells (PEMFCs) offer advantages such as fast start-up, high efficiency, low operating temperature, long service life, and zero noise and pollution, making them promising for applications in automobiles, homes, small and medium-sized power plants, and portable devices.

[0003] A proton exchange membrane fuel cell (PEMFC) consists of bipolar plates (BPP), end plates (EP), membrane electrode assemblies (MEA), and a gas diffusion layer (GDL). During operation, the bipolar plates support the MEA, current collection, heat conduction, gas distribution, and separation of fuel and oxidant. Since most currently used PEMs are perfluorosulfonic acid (PFSA) membranes, the ends of their molecular branches are highly oxidizing sulfonic acid groups. Furthermore, PFSA membranes degrade during fuel cell use, releasing fluoride ions. Therefore, in the fuel cell operating environment, the bipolar plates must be able to withstand sulfonic acid with a pH of 2–3, approximately 2 ppm of hydrofluoric acid, and environmental conditions of approximately 70°C. This places extremely high demands on the corrosion resistance of the bipolar plates.

[0004] Traditional graphite bipolar plates exhibit excellent corrosion resistance and electrical conductivity, but their poor mechanical strength, large size, brittleness, high processing cost, and low processing efficiency make them increasingly difficult to meet the requirements of smaller size, higher power density, lower manufacturing cost, higher reliability, and ease of large-scale deployment for automotive fuel cells. In contrast, metal bipolar plates offer advantages such as thinness, high mechanical strength, high air resistance, good processability, and high resource recyclability. However, metal bipolar plates are susceptible to surface corrosion. Therefore, surface treatment or special coatings have become the mainstream research direction for improving the corrosion resistance of metal bipolar plates in fuel cells.

[0005] Current research on metal bipolar plates mainly focuses on applying protective coatings to the surfaces of stainless steel or titanium plates. Although significant breakthroughs have been made in preparing protective coatings on these two metal surfaces, and most of the technical objectives specified in DOE 2025 have been achieved, some key objectives remain difficult to meet. For example, titanium alloys are expensive, and using titanium alloys as substrates makes it difficult to meet the DOE 2025 requirement for low-cost bipolar plates (US$2 per kW). -1Stainless steel is relatively heavy, making it difficult to meet the DOE 2025 requirement for mass power density (0.18 kg·kW). -1 According to regulations, while quality can be controlled by reducing the thickness of bipolar plates, excessively reducing thickness will inevitably damage its mechanical properties. Aluminum alloys have low density, low cost, and high conductivity, but their poor corrosion resistance limits their direct application. Moreover, existing composite coating technologies are costly and complex, while traditional coatings, such as MXene / chitosan composite coatings, metal gradient composite coatings, and amorphous carbon coatings constructed by electrodeposition, cannot simultaneously improve corrosion resistance and conductivity, and are still in the stage of tackling key technical challenges. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an aluminum-based metal bipolar plate, its preparation method, and its applications. The aluminum-based metal bipolar plate of this invention offers advantages in terms of lightweight design, cost control, thermal conductivity, and electrical conductivity. It can significantly improve overall corrosion resistance, enhance bipolar plate quality, and reduce costs, demonstrating promising prospects for large-scale production and application.

[0007] In a first aspect, the aluminum-based metal bipolar plate provided by the present invention includes: Aluminum-based matrix: including industrial pure aluminum or aluminum alloy; Modified layer: formed on the surface of the aluminum substrate by ion implantation; the implanted element includes one or more of N, Ti, Cr, Ta, Nb, and Ni; Functional coating: formed on the surface of the modified layer by magnetron sputtering; the material of the functional coating includes one or more of Ti, Cr, Ta, Nb, Ni, Al and their nitrides and carbides, forming a single-layer or multi-layer structure.

[0008] This invention relates to an aluminum-based metal bipolar plate obtained through an interface control method and protective coating technology. It employs a specific ion implantation modification layer and a magnetron sputtering functional coating. The ion implantation surface modification technology is integrated and matched with the magnetron sputtering functional coating to strengthen interlayer bonding and improve coating corrosion resistance. This effectively solves the problems of poor film-substrate bonding in current aluminum-based metal bipolar plates for fuel cells, which fail to effectively improve corrosion resistance and interfacial conductivity, and lack specific industrial applications. It meets the technical requirements of lightweight, high-efficiency metal bipolar plates for fuel cell stacks. Furthermore, aluminum alloys are low-cost and lightweight, and the raw material cost for coating preparation is also relatively low. This invention is of great significance for the fuel cell field, which requires lightweight, low-cost, and high-performance materials.

[0009] Preferably, when the functional coating is chromium nitride, the implanted element is N or Cr; when the functional coating is titanium nitride, the implanted element is N or Ti; and when the functional coating is titanium carbide, the implanted element is C or Ti. The aluminum-based metal bipolar plate provided by this invention can better block the pitting corrosion propagation of the aluminum substrate in an aluminum-based and corrosive acidic environment system. The specific compound formed between the implanted element and the aluminum substrate forms a compositional transition interface with the magnetron sputtered deposition layer, more effectively overcoming the technical difficulties of poor interfacial conductivity and weak adhesion caused by the oxide film on the aluminum substrate surface, resulting in poor aluminum corrosion resistance.

[0010] Preferably, the implanted element is implanted into an aluminum substrate to form a modified layer; more preferably, the implantation energy is 50~200 keV, more preferably 80~100 keV, and the implantation dose is 1~5×10⁻⁶. 17 ions / cm 2 Preferably 2~3×10 17 ions / cm 2 In this invention, the types of injected elements are optimized based on the composition of the functional coating, and high-energy injection under certain conditions can improve the bonding force, enhance the corrosion resistance to acidic working fluids in fuel cells, and facilitate the formation of a continuous compositional gradient transition layer between the modified layer and the functional coating.

[0011] Preferably, the thickness of the modified layer is 10~1000 nm, more preferably 50~500 nm, and even more preferably 100~200 nm. Preferably, the thickness of the functional coating is 10~10000 nm, more preferably 50~1000 nm, and even more preferably 200~400 nm. Optimizing the thickness of the modified layer and the functional coating can better enhance the corrosion resistance of the coating.

[0012] Preferably, the aluminum matrix is ​​a 3-series aluminum alloy, a 5-series aluminum alloy, or a 6-series aluminum alloy; preferably, the thickness of the aluminum alloy is 2 to 10 mm.

[0013] Secondly, the present invention provides a method for preparing the aluminum-based metal bipolar plate, comprising: 1) Perform surface pretreatment on the aluminum substrate.

[0014] 2) Ion implantation is performed on the aluminum substrate treated in step 1) to form a modified layer on the surface of the aluminum substrate.

[0015] 3) The aluminum substrate treated in step 2) is subjected to magnetron sputtering to form a functional coating on the surface of the modified layer.

[0016] This invention combines ion implantation modification with magnetron sputtering functional coating to treat aluminum substrates, effectively controlling costs, reducing weight, improving conductivity, and enhancing corrosion resistance. Specific elements are implanted into the pretreated aluminum alloy substrate surface using a high-energy ion beam, achieving surface activation and interface modification, significantly improving surface properties. Simultaneously, a functional coating is deposited on the modified layer using magnetron sputtering. During coating deposition, high-energy particles bombard and densify the coating, while simultaneously etching the interface, resulting in a dense, defect-free, and uniform coating structure that firmly bonds with the substrate formed by ion implantation and the modified layer.

[0017] Preferably, in step 1), the surface pretreatment is to grind, polish and degrease the aluminum substrate.

[0018] Preferably, the grinding and polishing includes sequentially grinding the aluminum substrate with sandpaper and polishing with polishing paste, and the degreasing and cleaning includes ultrasonic cleaning and drying.

[0019] More preferably, the grinding and polishing is performed by grinding with #400, #600, #1000, #1500, and #2000 sandpaper in sequence, followed by polishing with 2.5 μm and 0.5 μm polishing pastes; the degreasing and cleaning is performed by ultrasonic cleaning in acetone, ethanol, and deionized water, respectively, followed by drying.

[0020] Preferably, in step 2), the injection energy is 50~200 keV and the injection dose is 1~5×10⁻⁶ keV. 17 ions / cm 2 Preferably, the vacuum level is set to 1.0 × 10⁻⁶. -1 ~1.0×10 -3 Pa, target power 50~150 W, injection energy 80~100 keV, injection dose 2~3×10 17 ions / cm 2 While better protecting the aluminum substrate, the injected elements form a concentration gradient transition zone on the surface of the aluminum substrate, resulting in better adhesion and strong corrosion resistance on the aluminum substrate surface, and facilitating subsequent processing.

[0021] More preferably, the ion implantation further includes: evacuating to a vacuum of 1.0 × 10⁻⁶. -3 When the pressure is below Pa, argon gas is introduced.

[0022] Preferably, step 3) includes glow discharge cleaning of the aluminum substrate followed by magnetron sputtering deposition.

[0023] Preferably, in the glow discharge cleaning, the vacuum level is set to 0.8~6 Pa, the target power to 10~50 W, the bias power supply voltage to 800~1200 V, the duty cycle to 30%~80%, and the glow discharge cleaning time to 10~60 min; in the magnetron sputtering deposition, a vacuum is drawn and argon gas is introduced, the vacuum level is set to 0.1~0.6 Pa, the target power to 50~150 W, the bias power supply voltage to 50~300 V, the duty cycle to 30%~80%, and the deposition time to 5~180 min. By coordinating and optimizing the parameters of the glow discharge cleaning and deposition processes, the corrosion resistance and conductivity of the aluminum-based bipolar plate for fuel cells can be further improved.

[0024] Further preferably, the glow discharge cleaning and / or magnetron sputtering deposition process further includes evacuating to a vacuum level of 3.0 × 10⁻⁶. -3 When the pressure is below Pa, argon gas is introduced.

[0025] The third invention provides the application of the aluminum-based metal bipolar plate or the preparation method of the aluminum-based metal bipolar plate in an electrolytic water hydrogen production device or a hydrogen fuel cell, preferably applied to the bipolar plate, end plate, diffusion layer of a fuel cell, or the coating preparation of an electrodialysis plate or a bipolar membrane plate.

[0026] The method of this invention can be well applied to hydrogen production devices through water electrolysis or hydrogen fuel cells, especially to the interface control of aluminum-based metal bipolar plates used in hydrogen fuel cells. It improves the quality of metal bipolar plates while reducing costs, giving them better corrosion resistance and conductivity, providing technical support for the engineering application of bipolar plates and laying the foundation for the widespread application of hydrogen fuel cells. Optimizing the coating control of aluminum-based metal bipolar plates, ion implantation surface modification can effectively remove the Al2O3 film on the aluminum alloy surface, enhancing the adhesion between the coating and the substrate. Simultaneously, based on the composition of the functional coating prepared by magnetron sputtering, the type of ion implanted is selected, and by controlling the elemental composition of the implanted ions, a continuous compositional gradient transition layer is constructed between the modified layer and the functional coating. This can more effectively alleviate stress concentration at the interface, significantly enhance the adhesion between the modified layer and the functional coating, and improve the overall corrosion resistance of the coating. This invention not only helps reduce the quality and manufacturing cost of bipolar plates but also has excellent prospects for large-scale production and application.

[0027] The beneficial effects of this invention are at least as follows: the aluminum-based metal bipolar plate of this invention has significant advantages in terms of lightweight, cost control, thermal conductivity, and electrical conductivity. Ion implantation surface modification of the pretreated substrate effectively removes the oxide film on the substrate surface, significantly enhancing the adhesion between the coating and the substrate, and improving overall corrosion resistance. Simultaneously, the seamless integration and compositional matching of the ion implantation surface modification technology with the magnetron sputtering functional coating formation process further enhances the adhesion between the two layers, alleviates interfacial stress concentration, and thus improves the overall structural stability and corrosion resistance of the coating. This invention not only helps reduce the weight and manufacturing cost of bipolar plates but also has excellent prospects for large-scale production and engineering applications. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be introduced one by one below. Obviously, the drawings described below are some embodiments of this invention. Without creative effort, those skilled in the art can further obtain other drawings based on the drawings of this application.

[0029] Figure 1 The potentiodynamic polarization curves of the aluminum-based metal bipolar plate protective coatings prepared in the embodiments and comparative examples of the present invention were measured at 70°C in an acidic etching solution of 0.5 M H2SO4 containing 2 ppm hydrofluoric acid.

[0030] Figure 2 This is a corrosion morphology diagram of the aluminum-based metal bipolar plate protective coating prepared in Example 1 of the present invention.

[0031] Figure 3 This is a corrosion morphology diagram of the aluminum-based metal bipolar plate protective coating prepared in Comparative Example 1 of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] The endpoints and any values ​​of the ranges disclosed in this invention 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 invention.

[0034] Unless otherwise specified, the techniques or conditions described in the embodiments of this invention shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Devices, instruments, reagents, etc., without specified manufacturers, are all conventional products that can be purchased through legitimate channels. All experimental reagents and raw materials involved are commercially available products, and all reagents are analytical grade products.

[0035] Example 1 This embodiment provides an aluminum-based metal bipolar plate and its preparation method, the steps of which are as follows: The 5083 aluminum alloy substrate (14×14×2 mm) was ground and polished. The substrate was then placed in a hydrocarbon cleaning agent (acetone) for 20 min to remove oil. After the oil removal was completed, the substrate was ultrasonically washed with water. The substrate was then placed in another hydrocarbon cleaning agent (ethanol) for 20 min to ultrasonically clean. After the cleaning was completed, the substrate was placed in pure water for ultrasonic cleaning and then dried.

[0036] Ion implantation surface modification: The cleaned substrate is placed into the ion implantation chamber, and a vacuum of 1.0 × 10⁻⁶ is drawn. -3 Below Pa, argon gas is introduced, and the vacuum degree is set to 1.0 × 10⁻⁶. -3 At Pa, nitrogen gas is introduced, the injected ions are nitrogen ions, the injection energy is set to 100 keV, and the injection dose is set to 2 × 10⁻⁶. 17 ions / cm 2 The thickness of the modified layer is 118 nm.

[0037] Magnetron sputtering functional coating: After ion implantation, the substrate is loaded into a magnetron sputtering apparatus and evacuated to a vacuum of 3.0 × 10⁻⁶. -3 Below Pa, argon gas is introduced, and the vacuum degree is set to 5.0 Pa. The titanium target is turned on with a power of 20 W, a bias voltage of 800 V, and a duty cycle of 80%. The substrate is then subjected to glow discharge cleaning for 30 min. After the substrate has been treated, it is placed into the coating chamber, and argon gas is introduced, with the vacuum degree set to 5 × 10⁻⁶ Pa. -1 Pa, turn on the chromium nitride target, set the target power to 100 W, set the bias power supply voltage to 80 V, the duty cycle to 50%, set the deposition time to 60 min, and the coating thickness to 306 nm.

[0038] The corrosion morphology of the aluminum-based metal bipolar plate protective coating prepared in Example 1 after testing its potentiodynamic properties in an acidic etching solution containing 2 ppm hydrofluoric acid at 70°C is shown in the figure. Figure 2 As shown.

[0039] Comparative Example 1 This comparative example provides an aluminum-based metal bipolar plate and its preparation method, the steps of which are as follows: A 5083 aluminum alloy substrate (14×14×2 mm) was ground and polished. The substrate was then immersed in a hydrocarbon cleaning agent (acetone) for 20 min to remove oil. After degreasing, the substrate was ultrasonically washed with water. The substrate was then immersed in another hydrocarbon cleaning agent (ethanol) for 20 min to undergo ultrasonic cleaning. After cleaning, the substrate was immersed in pure water for ultrasonic cleaning and then dried. The corrosion morphology of the aluminum-based metal bipolar plate prepared in Comparative Example 1 after testing its potentiodynamic properties at 70°C in a 0.5 M H₂SO₄ acidic etching solution containing 2 ppm hydrofluoric acid is shown below. Figure 3 As shown.

[0040] Comparative Example 2 This comparative example provides an aluminum-based metal bipolar plate and its preparation method, the steps of which are as follows: The 5083 aluminum alloy substrate (14×14×2 mm) was ground and polished. The substrate was then placed in a hydrocarbon cleaning agent (acetone) for 20 min to remove oil. After the oil removal was completed, the substrate was ultrasonically washed with water. The substrate was then placed in another hydrocarbon cleaning agent (ethanol) for 20 min to ultrasonically clean. After the cleaning was completed, the substrate was placed in pure water for ultrasonic cleaning and then dried.

[0041] The cleaned substrate was placed in a magnetron sputtering ion plating furnace and evacuated to a vacuum level of 3.0 × 10⁻⁶. -3 Below Pa, argon gas is introduced, the vacuum degree is set to 5.0 Pa, the titanium target is turned on with a power of 20 W, the bias voltage is set to 800 V, the duty cycle is 80%, and glow discharge cleaning is performed on the substrate for 30 min.

[0042] After the above-treated substrate is placed into the coating chamber, argon gas is introduced, and the vacuum level is set to 5 × 10⁻⁶. -1 Pa, turn on the chromium nitride target, set the target power to 100 W, set the bias power supply voltage to 80 V, the duty cycle to 50%, set the deposition time to 60 min, and the coating thickness to 260 nm.

[0043] Example 2 This embodiment provides an aluminum-based metal bipolar plate and its preparation method, the steps of which are as follows: The 5083 aluminum alloy substrate (14×14×2 mm) was ground and polished. The substrate was then placed in a hydrocarbon cleaning agent (acetone) for 20 min to remove oil. After the oil removal was completed, the substrate was ultrasonically washed with water. The substrate was then placed in another hydrocarbon cleaning agent (ethanol) for 20 min to ultrasonically clean. After the cleaning was completed, the substrate was placed in pure water for ultrasonic cleaning and then dried.

[0044] Ion implantation surface modification: The cleaned substrate is placed into the ion implantation chamber, and a vacuum of 1.0 × 10⁻⁶ is drawn. -3Below Pa, argon gas is introduced, and the vacuum degree is set to 1.0 × 10⁻⁶. -3 Pa, turn on the chromium target, implant ions are chromium ions, set the implantation energy to 80 keV, and set the implantation dose to 2 × 10⁻⁶. 17 ions / cm 2 The thickness of the modified layer is 77 nm.

[0045] Magnetron sputtering functional coating: After ion implantation, the substrate is loaded into a magnetron sputtering apparatus and evacuated to a vacuum of 3.0 × 10⁻⁶. -3 Below Pa, argon gas is introduced, and the vacuum degree is set to 5.0 Pa. The titanium target is turned on with a power of 20 W, a bias voltage of 800 V, and a duty cycle of 80%. The substrate is then subjected to glow discharge cleaning for 30 min. After the substrate has been treated, it is placed into the coating chamber, and argon gas is introduced, with the vacuum degree set to 5 × 10⁻⁶ Pa. -1 Pa, turn on the chromium nitride target, set the target power to 100 W, set the bias power supply voltage to 80 V, set the duty cycle to 50%, set the deposition time to 60 min, and set the coating thickness to 277 nm.

[0046] Example 3 This embodiment provides an aluminum-based metal bipolar plate and its preparation method, the steps of which are as follows: The 5083 aluminum alloy substrate (14×14×2 mm) was ground and polished. The substrate was then placed in a hydrocarbon cleaning agent (acetone) for 20 min to remove oil. After the oil removal was completed, the substrate was ultrasonically washed with water. The substrate was then placed in another hydrocarbon cleaning agent (ethanol) for 20 min to ultrasonically clean. After the cleaning was completed, the substrate was placed in pure water for ultrasonic cleaning and then dried.

[0047] The cleaned substrate was placed into the ion implantation chamber, and a vacuum of 1.0 × 10⁻⁶ was applied. -3 Below Pa, argon gas is introduced, and the vacuum degree is set to 1.0 × 10⁻⁶. -3 At Pa, nitrogen gas is introduced, the injected ions are nitrogen ions, the injection energy is set to 100 keV, and the injection dose is set to 2 × 10⁻⁶. 17 ions / cm 2 Then, the chromium target was activated, chromium ions were implanted, the implantation energy was set to 80 keV, and the implantation dose was set to 2 × 10⁻⁶. 17 ions / cm 2 .

[0048] The potentiodynamic polarization curves of the aluminum-based metal bipolar plates prepared in each embodiment and comparative example were measured at 70°C in an acidic etching solution of 0.5M H2SO4 containing 2 ppm hydrofluoric acid.

[0049] Table 1

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aluminum-based metal bipolar plate, characterized in that, include: Aluminum-based matrix: including industrial pure aluminum or aluminum alloy; Modified layer: formed on the surface of the aluminum substrate by ion implantation; the implanted element includes one or more of N, Ti, Cr, Ta, Nb, and Ni; Functional coating: formed on the surface of the modified layer by magnetron sputtering; the material of the functional coating includes one or more of Ti, Cr, Ta, Nb, Ni, Al and their nitrides and carbides, forming a single-layer or multi-layer structure.

2. The aluminum-based metal bipolar plate according to claim 1, characterized in that, When the functional coating is chromium nitride, the implanted element is N or Cr; when the functional coating is titanium nitride, the implanted element is N or Ti.

3. The aluminum-based metal bipolar plate according to claim 1 or 2, characterized in that, The thickness of the modified layer is 10~1000 nm, preferably 50~500 nm.

4. The aluminum-based metal bipolar plate according to any one of claims 1 to 3, characterized in that, The thickness of the functional coating is 10~10000 nm, preferably 50~1000 nm.

5. The aluminum-based metal bipolar plate according to any one of claims 1 to 4, characterized in that, The aluminum matrix is ​​a 3-series aluminum alloy, a 5-series aluminum alloy, or a 6-series aluminum alloy.

6. The method for preparing the aluminum-based metal bipolar plate according to any one of claims 1 to 5, characterized in that, include: 1) Perform surface pretreatment on the aluminum substrate; 2) Ion implantation is performed on the aluminum substrate treated in step 1) to form a modified layer on the surface of the aluminum substrate; 3) The aluminum substrate treated in step 2) is subjected to magnetron sputtering to form a functional coating on the surface of the modified layer.

7. The preparation method according to claim 6, characterized in that, In step 1), the surface pretreatment includes grinding and polishing the aluminum substrate and degreasing and cleaning; preferably, the grinding and polishing includes sandpaper grinding and polishing with polishing paste on the aluminum substrate in sequence, and the degreasing and cleaning includes ultrasonic cleaning and drying.

8. The preparation method according to claim 6 or 7, characterized in that, In step 2), the injection energy is 50~200 keV, and the injection dose is 1~5×10⁻⁶. 17 ions / cm 2 Preferably, the vacuum degree is set to 1.0 × 10⁻⁶. -1 ~1.0×10 -3 Pa, target power 50~150 W, injection energy 80~100 keV, injection dose 2~3×10 17 ions / cm 2 .

9. The preparation method according to any one of claims 6 to 8, characterized in that, Step 3) includes glow discharge cleaning of the aluminum substrate followed by magnetron sputtering deposition. Preferably, in the glow discharge cleaning, the vacuum level is set to 0.8~6 Pa, the target power is 10~50 W, the bias power supply voltage is 800~1200 V, the duty cycle is 30%~80%, and the glow discharge cleaning time is 10~60 min. In the magnetron sputtering deposition, a vacuum is drawn and argon gas is introduced, the vacuum level is set to 0.1~0.6 Pa, the target power is 50~150 W, the bias power supply voltage is 50~300 V, the duty cycle is 30%~80%, and the deposition time is 5~180 min.

10. The application of the aluminum-based metal bipolar plate according to any one of claims 1 to 5 or the preparation method of the aluminum-based metal bipolar plate according to any one of claims 6 to 9 in a water electrolysis hydrogen production device or a hydrogen fuel cell, preferably in a bipolar plate of a fuel cell.

Images