A high-conductivity corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates, a preparation method and applications

Abstract

This invention discloses a highly conductive and corrosion-resistant coating for titanium bipolar plates used in PEMWE hydrogen production, its preparation method, and its application. The preparation method includes the following steps: Step 1: A Ti seed layer is deposited on a substrate using magnetron sputtering, with a Ti target power of 100~130 W and a substrate bias voltage of -100~-250 V; Step 2: A TiMo alloy transition layer is deposited on the surface of the Ti seed layer using magnetron sputtering; Step 3: A TiMoC composite layer is deposited on the surface of the TiMo alloy transition layer using magnetron sputtering. This invention modifies titanium bipolar plates through a three-layer coating system formed by Ti / TiMo / TiMoC. The Ti seed layer improves the adhesion between the coating and the substrate, the TiMo alloy transition layer enhances corrosion resistance, and the TiMoC composite layer improves conductivity while ensuring corrosion resistance. The resulting coating exhibits excellent comprehensive performance in the PEMWE hydrogen production environment.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane electrolysis (PEMWE) for hydrogen production, specifically to a highly conductive and corrosion-resistant coating for titanium bipolar plates used in PEMWE hydrogen production, its preparation method, and its application. Background Technology

[0002] Hydrogen energy, as a clean and renewable high-quality secondary energy source, is an ideal alternative to traditional fossil fuels and has become a core carrier and development strategy of the new energy revolution. Hydrogen production through water electrolysis driven by renewable energy is a key path to achieving carbon neutrality and sustainable development. Proton exchange membrane electrolysis (PEMWE) hydrogen production technology is a highly efficient hydrogen production technology with advantages such as high energy conversion efficiency, fast start-up, low operating temperature, and compact structure. It can be efficiently coupled with fluctuating renewable energy sources such as wind power and photovoltaics, making it one of the most promising green hydrogen production technologies currently available. The bipolar plate, as the core component of the PEMWE preparation equipment, directly affects the hydrogen production efficiency and equipment lifespan.

[0003] PEMWE bipolar plates face extreme synergistic conditions of high oxygen evolution overpotential and strong acidic medium at the anode, imposing stringent requirements on the corrosion resistance of the materials. Pure Ti bipolar plates exhibit excellent corrosion resistance in the PEMWE hydrogen production environment, making them the current mainstream preferred material. However, long-term operation in the high-potential, oxygen-rich environment of the anode easily leads to the formation of an insulating TiO2 passivation film on the surface, resulting in a significant increase in the interfacial contact resistance between the bipolar plate and the porous transport layer, severely limiting the battery's output performance. To solve this problem, a conductive coating is typically deposited on the surface of the Ti bipolar plate.

[0004] Existing coating technologies suffer from the following problems: traditional conductive coatings, such as precious metal coatings like Au and Pt, are expensive and unsuitable for large-scale applications; while pure carbon-based coatings are low-cost, they lack corrosion resistance and have poor adhesion to Ti-based materials, making them prone to electrochemical oxidation (C + 2H₂O → CO₂ + 4H₂O) under PEMWE anodic conditions. + +4e - This leads to coating dissolution and poor durability; while existing non-precious metal coating systems are not corrosion resistant enough in the acidic environment of PEMWE hydrogen production, and their performance degrades significantly after long-term use. Summary of the Invention

[0005] The technical solution adopted in this invention is: a highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates, its preparation method and application.

[0006] It includes a Ti seed layer, a TiMo alloy transition layer and a TiMoC composite layer stacked sequentially; the Ti seed layer is coated on the surface of the substrate.

[0007] Furthermore, the thickness of the Ti seed layer is 0.25~0.3 μm, the thickness of the TiMo alloy transition layer is 0.35~0.5 μm, and the thickness of the TiMoC composite layer is 0.75~1 μm.

[0008] A method for preparing a highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates includes the following steps: Step 1: A Ti seed layer is deposited on the substrate using magnetron sputtering. The Ti target is subjected to a power of 100~130 W, and the substrate is subjected to a bias voltage of -100~-250 V. Step 2: A TiMo alloy transition layer is deposited on the surface of the Ti seed layer by magnetron sputtering; wherein the power applied to the Ti target is 130-160 W, the power applied to the Mo target is 15-30 W, and a bias voltage of -150 to -250 V is applied to the substrate; Step 3: A TiMoC composite layer is deposited on the surface of the TiMo alloy transition layer by magnetron sputtering, wherein the power applied to the Ti target is 130-160 W, the power applied to the Mo target is 15-30 W, the power applied to the graphite target is 150-180 W, and a bias voltage of -150 to -250 V is applied to the substrate.

[0009] Furthermore, the substrate is first pretreated, and then the substrate and the target are pre-sputtered.

[0010] Furthermore, the substrate pre-sputtering process is as follows: The substrate was cleaned by plasma etching. Ar gas of 20-40 sccm was introduced and a bias voltage of -700 to -900 V was applied to the substrate at a pressure of 3-6 Pa for 8-15 min.

[0011] Furthermore, the pre-sputtering process of the target material is as follows; Sputtering cleaning was performed by applying 90-120 W power to the Ti target, 90-120 W power to the Mo target, and 100-150 W power to the graphite target using a DC pulse power supply.

[0012] Furthermore, the substrate is heated during the magnetron sputtering process to a temperature of 120–200 °C.

[0013] Furthermore, the preprocessing procedure is as follows: The substrate is ground and polished, then ultrasonically cleaned, dried, and placed in a magnetron sputtering device, and a vacuum is drawn; Ar gas is introduced until the pressure reaches 5 Pa.

[0014] Application of a highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates, the coating being used in PEMWE hydrogen production titanium bipolar plates.

[0015] Furthermore, the bipolar plate is used on the anode side.

[0016] The beneficial effects of this invention are: This invention modifies titanium bipolar plates using a three-layer coating system formed by Ti / TiMo / TiMoC. The Ti seed layer improves the adhesion between the coating and the substrate, the TiMo alloy transition layer enhances corrosion resistance, and the TiMoC composite layer improves conductivity while maintaining corrosion resistance. The resulting coating exhibits excellent overall performance in the PEMWE hydrogen production environment, with an interfacial contact resistance as low as 4.53 mΩ·cm² (at 3 MPa) and a corrosion current density of only 1.65 μA / cm². 2 The stable current density after being maintained at a constant potential polarization of 1.8 V for 10 h in a 0.5 M sulfuric acid solution at 70 °C was as low as 16.84 μA / cm². 2 The ICR of the coating after constant potential polarization increased slightly to 10.32 mΩ·cm 2 @3 MPa, far lower than TA4 matrix (74.25 mΩ·cm) 2 @3 MPa). Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the preparation method of the present invention.

[0018] Figure 2 This is a microscopic morphology diagram of the coating obtained in Example 1 of the present invention.

[0019] Figure 3 This is a microscopic morphology diagram of the coating cross-section obtained in Embodiment 1 of the present invention.

[0020] Figure 4 The initial interface contact resistance curve between the coating and the substrate TA4 obtained in Embodiment 1 of the present invention is shown.

[0021] Figure 5 The image shows the potentiodynamic polarization curves of the coating and the TA4 substrate obtained in Example 1 of this invention.

[0022] Figure 6 The corrosion current density response curve of the coating after 10 h of constant potential polarization at 1.8 V is obtained in Example 1 of the present invention.

[0023] Figure 7 The image shows the interface contact resistance curve obtained in Example 1 of this invention after the coating and the TA4 substrate were polarized at a constant potential of 1.8 V for 10 h. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1As shown, a method for preparing a highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates includes the following steps: Step 1: The substrate is first pretreated, and then the substrate and target are pre-sputtered. The preprocessing process is as follows: The substrate is ground and polished, then ultrasonically cleaned, dried, and placed in a magnetron sputtering device, and a vacuum is drawn; Ar gas is introduced until the pressure reaches 5 Pa.

[0026] The substrate pre-sputtering process is as follows: The substrate was cleaned by plasma etching. Ar gas of 20-40 sccm was introduced and a bias voltage of -700 to -900 V was applied to the substrate at a pressure of 3-6 Pa for 8-15 min.

[0027] The pre-sputtering process of the target material is as follows; Sputtering cleaning was performed by applying 90-120 W power to the Ti target, 90-120 W power to the Mo target, and 100-150 W power to the graphite target using a DC pulse power supply.

[0028] Ar gas of 20-40 sccm was introduced, and Ti seed layer was deposited on the substrate by magnetron sputtering at a chamber pressure of 0.3-0.8 Pa. The Ti target power was 100-130 W, the substrate was subjected to a bias voltage of -100--250 V, and the deposition time was 10-30 min.

[0029] Step 2: Introduce 20-40 sccm of Ar gas and perform magnetron sputtering at a chamber pressure of 0.3-0.8 Pa to deposit a TiMo alloy transition layer on the surface of the Ti seed layer; wherein the applied power of the Ti target is 130-160 W, the applied power of the Mo target is 15-30 W, and the deposition time is 0.4-0.6 h.

[0030] Step 3: Introduce 20-40 sccm of Ar gas and perform magnetron sputtering at a chamber pressure of 0.3-0.8 Pa to deposit a TiMoC composite layer on the surface of the TiMo alloy transition layer. The bias voltage of the Ti target is 130-160 W, the bias voltage of the Mo target is 15-30 W, the bias voltage of the graphite target is 150-180 W, and the deposition time is 1.5-2.5 h.

[0031] During magnetron sputtering, the substrate is heated to a temperature of 120–200 °C. After magnetron sputtering, the gas path is shut off, while the mechanical and molecular pumps are kept running to maintain the coating under vacuum for at least 3 hours, followed by natural cooling.

[0032] The resulting coating has a Ti seed layer thickness of 0.25~0.3 μm, a TiMo alloy transition layer thickness of 0.35~0.5 μm, and a TiMoC composite outermost layer thickness of 0.75~1 μm.

[0033] Example 1 A method for preparing a highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates includes the following steps: First, the substrate was pretreated. The 0.2 mm thick TA4 foil was polished with SiC sandpaper of 400#, 800#, 1200# and 2000#, and then polished with diamond polishing liquid (0.5 μm particle size) until the surface roughness Ra≤0.1 μm. Then, it was ultrasonically cleaned in acetone and anhydrous ethanol for 10 min to remove surface oil and impurities, and then dried with compressed air and placed in a vacuum desiccator for later use.

[0034] The pretreated substrate was mounted on the substrate stage of the magnetron sputtering equipment, and the pure Ti substrate was heated to a target temperature of 150°C. A mechanical pump and a molecular pump were then used to sequentially evacuate the substrate to a vacuum level of 5 × 10⁻⁶. -3 Below Pa, high-purity Ar gas is introduced until the pressure in the chamber stabilizes at around 5 Pa, and the substrate stage speed is set to 20 rpm.

[0035] The substrate was sputtered cleaned using a bias power supply, the Ti and Mo targets were sputtered cleaned using a DC pulse power supply, and the targets were sputtered cleaned using an RF power supply.

[0036] The substrate pre-sputtering process is as follows: The Ar gas flow rate was 30 sccm, the pre-sputtering pressure was 5 Pa, the substrate baffle was opened, the target baffle was closed, the bias voltage was -800V, and the time was 10 min.

[0037] The target sputtering process is as follows: Close the substrate baffle, open the target baffle, and apply power to the target using a DC pulse power supply. The power for the Ti target is 100 W, the power for the Mo target is 100 W, and the power for the graphite target is 120 W. The time is 10 min.

[0038] Step 1: Ar gas flow rate is 30 sccm, pressure is 0.5 Pa, turn on the Ti target DC pulse power supply for 20 min, DC pulse power supply applied power is 120 W, sample (i.e. the above-treated substrate, the intermediate system formed by the substrate and the coating on the substrate in the following preparation process are all referred to as the sample) applied bias voltage of -200 V.

[0039] Step 2: The Ar gas flow rate is 30 sccm and the pressure is 0.5 Pa. At the same time, the DC pulse power supply of Ti and Mo targets is turned on for co-deposition. The power of Ti target is 150 W and the power of Mo target is 20 W. The bias voltage applied to the sample is -200 V and the deposition time is 0.5 h.

[0040] Step 3: Simultaneously turn on the DC pulse power supply for the Ti and Mo targets and the RF power supply for the graphite target for co-deposition. The pressure is 0.5 Pa, the power of the Ti target is 150 W, the power of the Mo target is 20 W, the power of the graphite target is 160 W, the bias voltage applied to the sample is -200 V, and the deposition time is 2 h.

[0041] The sample is heated during the magnetron sputtering process at a temperature of 200 °C.

[0042] After sputtering, the gas path is shut off while the mechanical pump and molecular pump are kept running, allowing the coating to remain under vacuum for more than 3 hours. Then, it is allowed to cool naturally to room temperature to relieve internal stress in the coating, suppress defect formation, and improve adhesion.

[0043] Example 2 A method for preparing a highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates includes the following steps: First, the substrate was pretreated. The 0.2 mm thick TA4 foil was polished with SiC sandpaper of 400#, 800#, 1200# and 2000#, and then polished with diamond polishing liquid (0.5 μm particle size) until the surface roughness Ra≤0.1 μm. Then, it was ultrasonically cleaned in acetone and anhydrous ethanol for 10 min to remove surface oil and impurities, and then dried with compressed air and placed in a vacuum desiccator for later use.

[0044] The pretreated substrate was mounted on the substrate stage of the magnetron sputtering equipment, and the pure Ti substrate was heated to a target temperature of 150°C. A mechanical pump and a molecular pump were then used to sequentially evacuate the substrate to a vacuum level of 5 × 10⁻⁶. -3 Below Pa, high-purity Ar gas is introduced until the pressure in the chamber stabilizes at around 5 Pa, and the substrate stage speed is set to 20 rpm.

[0045] The substrate was sputtered cleaned using a bias power supply, the Ti and Mo targets were sputtered cleaned using a DC pulse power supply, and the targets were sputtered cleaned using an RF power supply.

[0046] The substrate pre-sputtering process is as follows: The Ar gas flow rate was 20 sccm, the pre-sputtering pressure was 6 Pa, the substrate baffle was opened, the target baffle was closed, the bias voltage was -700V, and the time was 15 min.

[0047] The target sputtering process is as follows: the substrate baffle is closed, the target baffle is opened, and a DC pulse power supply is used to apply power to the target. The power for Ti target is 120 W, the power for Mo target is 90 W, and the power for graphite target is 150 W. The time is 8 min.

[0048] Step 1: Ar gas flow rate is 20 sccm, pressure is 0.8 Pa, turn on the Ti target DC pulse power supply for 30 min, DC pulse power supply applied power is 130 W, sample (i.e. the above-treated substrate, the intermediate system formed by the substrate and the coating on the substrate in the following preparation process are all referred to as the sample) applied bias voltage of -250 V.

[0049] Step 2: The Ar gas flow rate is 20 sccm and the pressure is 0.8 Pa. At the same time, the DC pulse power supply of Ti and Mo targets is turned on for co-deposition. The power of Ti target is 130 W and the power of Mo target is 30 W. The bias voltage applied to the sample is -250 V and the deposition time is 0.6 h.

[0050] Step 3: Simultaneously turn on the DC pulse power supply for the Ti and Mo targets and the RF power supply for the graphite target for co-deposition. The pressure is 0.8 Pa, the power of the Ti target is 130 W, the power of the Mo target is 30 W, the power of the graphite target is 180 W, the bias voltage applied to the sample is -150 V, and the deposition time is 2.5 h.

[0051] The sample is heated during the magnetron sputtering process at a temperature of 200 °C.

[0052] After sputtering, the gas path is shut off while the mechanical pump and molecular pump are kept running, allowing the coating to remain under vacuum for more than 3 hours. Then, it is allowed to cool naturally to room temperature to relieve internal stress in the coating, suppress defect formation, and improve adhesion.

[0053] Example 3 A method for preparing a highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates includes the following steps: First, the substrate was pretreated. The 0.2 mm thick TA4 foil was polished with SiC sandpaper of 400#, 800#, 1200# and 2000#, and then polished with diamond polishing liquid (0.5 μm particle size) until the surface roughness Ra≤0.1 μm. Then, it was ultrasonically cleaned in acetone and anhydrous ethanol for 10 min to remove surface oil and impurities, and then dried with compressed air and placed in a vacuum desiccator for later use.

[0054] The pretreated substrate was mounted on the substrate stage of the magnetron sputtering equipment, and the pure Ti substrate was heated to a target temperature of 150°C. A mechanical pump and a molecular pump were then used to sequentially evacuate the substrate to a vacuum level of 5 × 10⁻⁶. -3Below Pa, high-purity Ar gas is introduced until the pressure in the chamber stabilizes at around 5 Pa, and the substrate stage speed is set to 20 rpm.

[0055] The substrate was sputtered cleaned using a bias power supply, the Ti and Mo targets were sputtered cleaned using a DC pulse power supply, and the targets were sputtered cleaned using an RF power supply.

[0056] The substrate pre-sputtering process is as follows: The Ar gas flow rate was 40 sccm, the pre-sputtering pressure was 3 Pa, the substrate baffle was opened, the target baffle was closed, the bias voltage was -900 V, and the time was 8 min.

[0057] The target sputtering process is as follows: the substrate baffle is closed, the target baffle is opened, and a DC pulse power supply is used to apply power to the target respectively. The power of the Ti target is 90 W, the power of the Mo target is 120 W, and the power of the graphite target is 100 W, for a time of 15 min.

[0058] Step 1: Ar gas flow rate is 40 sccm, pressure is 0.3 Pa, turn on the Ti target DC pulse power supply for 10 min, DC pulse power supply applied power is 100 W, sample (i.e. the above-treated substrate, the intermediate system formed by the substrate and the coating on the substrate in the following preparation process are all referred to as the sample) applied bias voltage of -100 V.

[0059] Step 2: The Ar gas flow rate is 40 sccm and the pressure is 0.3 Pa. At the same time, the DC pulse power supply of Ti and Mo targets is turned on for co-deposition. The power of Ti target is 160 W and the power of Mo target is 15 W. The bias voltage applied to the sample is -150 V and the deposition time is 0.4 h.

[0060] Step 3: Simultaneously turn on the DC pulse power supply for the Ti and Mo targets and the RF power supply for the graphite target for co-deposition. The pressure is 0.3 Pa, the power of the Ti target is 160 W, the power of the Mo target is 15 W, the power of the graphite target is 150 W, the bias voltage applied to the sample is -250 V, and the deposition time is 1.5 h.

[0061] The sample is heated during the magnetron sputtering process at a temperature of 200 °C.

[0062] After sputtering, the gas path is shut off while the mechanical pump and molecular pump are kept running, allowing the coating to remain under vacuum for more than 3 hours. Then, it is allowed to cool naturally to room temperature to relieve internal stress in the coating, suppress defect formation, and improve adhesion.

[0063] The coating surface obtained in Example 1 was observed using a scanning electron microscope, and the results are as follows: Figure 2As shown in the figure, the obtained TiMoC composite coating has a smooth surface, no cracks or pores, and exhibits a uniform granular structure.

[0064] The cross-section of the coating obtained in Example 1 was scanned, and the results are as follows: Figure 3 As shown in the figure, the three-layer structure has a clear interface and tight bonding, with no obvious delamination or peeling. The coating system covers the surface of the TA4 substrate, with a Ti seed layer thickness of 0.28 μm, a TiMo alloy transition layer thickness of 0.42 μm, and a TiMoC composite outermost layer thickness of 0.9 μm.

[0065] To illustrate the results of the coating obtained by the present invention, electrochemical tests and interfacial contact resistance (ICR) tests were performed on the coating obtained in Example 1 and on a TA4 substrate without the coating. The results are as follows: Figures 4-7 As shown.

[0066] The electrochemical testing method is as follows: Electrochemical tests were performed on the coated samples in a PEMWE simulated environment. The test solution was 0.5 M H₂SO₄ + 5 ppm NaF at 70℃, pre-purged with air for 10 h. The electrochemical experiment used a water bath heated electrolytic cell. The reference electrode was Ag / AgCl with a salt bridge (filled with saturated KCl solution), the auxiliary electrode was Pt foil, and the working electrode was the sample to be tested. Before the electrochemical test, an open-circuit potential test was performed for 1 h, followed by a potential scan range of potentiodynamic polarization (PDP) testing. The scanning range was 0.3 V (vs. OCP) to 2.5 V (vs. Ag / AgCl), with a scan rate of 1 mV / s. The accelerated stress cycle test adopted the constant potential polarization mode, with a potential of 1.8 V (vs. Ag / AgCl).

[0067] During the interfacial contact resistance (ICR) test, the sample is sandwiched between two sheets of hydrophobic carbon paper, and then pressed firmly between two gold-plated copper cylinders on the resistance tester. The software records the ICR value in real time during the pressure change process. When only a single sheet of hydrophobic carbon paper is placed between the upper and lower copper electrodes, the measured total resistance is... R 1; When the sample and carbon paper are sandwiched in a structure, the total resistance measured is: R 2. Assuming the resistivity of both the hydrophobic carbon paper and the sample is sufficiently low and negligible, the ICR between the sample and the hydrophobic carbon paper is calculated using the following formula: ICR=( R 2– R 1) / 2 As shown in the figure, the initial interfacial contact resistance between the TA4 substrate and the Ti / TiMo / TiMoC composite coating is 25.19 mΩ·cm. 2 @3 MPa and 4.54 mΩ·cm 2@3 MPa; the corrosion current densities of the TA4 substrate and the Ti / TiMo / TiMoC composite coating were 57.9 μA / cm², respectively. 2 and 1.65 μA / cm 2 The stable current densities of the TA4 substrate and the Ti / TiMo / TiMoC composite coating under constant potential polarization at 1.8 V were 118.51 μA / cm², respectively. 2 and 16.84 μA / cm 2 This indicates that the passivation film is stable and there is no continuous corrosion; after potentiostatic polarization, the ICR of TA4 soared to 74.25 mΩ·cm. 2 At 3 MPa, the coating ICR only increased slightly to 10.32 mΩ·cm. 2 @3 MPa indicates that the coating obtained by the present invention can maintain low contact resistance and high corrosion resistance for a long time under extreme working conditions.

[0068] The coating obtained by this invention comprises a Ti seed layer, a TiMo alloy transition layer, and a TiMoC composite layer stacked sequentially. The three-layer structure is synergistically designed and functionally coupled, rather than a simple superposition of functional layers. Without the Ti seed layer, the TiMo or TiMoC layer would be directly deposited on the TA4 surface. Due to lattice mismatch and abrupt changes in elastic modulus, the interface defect density would increase, making it prone to early delamination under electrochemical cyclic stress. Without the TiMo alloy transition layer, the oxygen diffusion barrier effect of Mo would be lost; simultaneously, the compositional buffering effect of Mo would be lacking, and abrupt changes in C concentration would lead to localized embrittlement or residual stress concentration. If a single layer of TiMoC is directly deposited, although the initial ICR is low, the lack of a gradient transition and the mismatch in thermal expansion coefficients would lead to the accumulation of huge internal stress during cooling and service, inducing microcracks; while the F in the PEMWE environment... - Ions can penetrate along cracks to the interface, accelerating localized corrosion and ultimately causing the coating to blister and peel off. This invention obtains a three-layer gradient system in the coating, with a Ti seed layer to ensure interfacial bonding, a TiMo transition layer to inhibit oxygen diffusion and regulate carbide nucleation, and a TiMoC outermost layer to provide a conductive and corrosion-resistant surface—only in this way can the triple contradiction of "bonding strength – corrosion resistance – conductivity" be synergistically resolved, and long-term stable operation of the PEMWE bipolar plate can be achieved without any precious metals.

Claims

1. A highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates, characterized in that, It includes a Ti seed layer, a TiMo alloy transition layer and a TiMoC composite layer stacked sequentially; the Ti seed layer is coated on the surface of the substrate.

2. The highly conductive and corrosion-resistant coating for PEMWE hydrogen production titanium bipolar plates according to claim 1, characterized in that, The thickness of the Ti seed layer is 0.25~0.3 μm, the thickness of the TiMo alloy transition layer is 0.35~0.5 μm, and the thickness of the TiMoC composite layer is 0.75~1 μm.

3. The method for preparing a highly conductive and corrosion-resistant coating for a PEMWE hydrogen production titanium bipolar plate as described in any one of claims 1 to 2, characterized in that, Includes the following steps: Step 1: A Ti seed layer is deposited on the substrate using magnetron sputtering. The Ti target is subjected to a power of 100~130 W, and the substrate is subjected to a bias voltage of -100~-250 V. Step 2: A TiMo alloy transition layer is deposited on the surface of the Ti seed layer by magnetron sputtering; wherein the power applied to the Ti target is 130-160 W, the power applied to the Mo target is 15-30 W, and a bias voltage of -150 to -250 V is applied to the substrate; Step 3: A TiMoC composite layer is deposited on the surface of the TiMo alloy transition layer by magnetron sputtering, wherein the power applied to the Ti target is 130-160 W, the power applied to the Mo target is 15-30 W, the power applied to the graphite target is 150-180 W, and a bias voltage of -150 to -250 V is applied to the substrate.

4. The method for preparing a highly conductive and corrosion-resistant coating for a PEMWE hydrogen production titanium bipolar plate according to claim 3, characterized in that, The substrate is first pretreated, and then the substrate and the target are pre-sputtered.

5. The method for preparing a highly conductive and corrosion-resistant coating for a PEMWE hydrogen production titanium bipolar plate according to claim 4, characterized in that, The substrate pre-sputtering process is as follows: The substrate was cleaned by plasma etching. Ar gas of 20-40 sccm was introduced and a bias voltage of -700 to -900 V was applied to the substrate at a pressure of 3-6 Pa for 8-15 min.

6. The method for preparing a highly conductive and corrosion-resistant coating for a PEMWE hydrogen production titanium bipolar plate according to claim 5, characterized in that, The pre-sputtering process of the target material is as follows; Sputtering cleaning was performed by applying 90-120 W power to the Ti target, 90-120 W power to the Mo target, and 100-150 W power to the graphite target using a DC pulse power supply.

7. The method for preparing a highly conductive and corrosion-resistant coating for a PEMWE hydrogen production titanium bipolar plate according to claim 3, characterized in that, The substrate is heated during the magnetron sputtering process to a temperature of 120–200 °C.

8. The method for preparing a highly conductive and corrosion-resistant coating for a PEMWE hydrogen production titanium bipolar plate according to claim 4, characterized in that, The preprocessing procedure is as follows: The substrate is ground and polished, then ultrasonically cleaned, dried, and placed in a magnetron sputtering device, and a vacuum is drawn; Ar gas is introduced until the pressure reaches 5 Pa.

9. The application of the highly conductive and corrosion-resistant coating as described in any one of claims 1 to 2 for PEMWE hydrogen production titanium bipolar plates, characterized in that, The coating is used in PEMWE's hydrogen-producing titanium bipolar plates.

10. The application of the highly conductive and corrosion-resistant coating for a PEMWE hydrogen production bipolar plate according to claim 9, characterized in that, The bipolar plate is used on the anode side.

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