Low-cost PEM water electrolysis coating material and preparation method thereof

Abstract

The invention provides a low-cost PEM water electrolysis coating material which comprises a base layer 2, a high-potential-resistant layer 3 and an enhanced conductive layer 4, the base layer 2 is deposited on the upper surface of a base body 1, the high-potential-resistant layer 3 is located on the surface of the base layer 2, and the enhanced conductive layer 4 is located on the high-potential-resistant layer 3. The coating material provided by the invention has high-potential corrosion resistance, can be suitable for a water electrolysis application scene, has excellent conductivity, and can effectively reduce the cost of the coating material in the field of water electrolysis without using noble metal or using trace noble metal.

Description

Technical Field:

[0001] The present invention relates to the field of coating technologies, and particularly to a low-cost coating material for PEM water electrolysis and a preparation method thereof. Background Art:

[0002] The PEM water electrolysis technology is an efficient and environmentally friendly hydrogen production method. By using a proton exchange membrane (PEM) as the separation membrane of the electrolytic cell, water is decomposed into hydrogen and oxygen. The PEM water electrolysis technology has the advantages of high current density, high hydrogen purity, fast response speed, etc., and has a wide range of application scenarios, including industrial, transportation, and power and other fields.

[0003] In the industrial field, the green hydrogen prepared by PEM water electrolysis can be applied to carbon-intensive industries such as ammonia synthesis, oil refining, chemical industry, and steel. In the transportation field, the PEM water electrolysis hydrogen production technology can be used to build hydrogen refueling stations to prepare green hydrogen on-site to support the development of fields such as fuel cell vehicles, railways, aviation, and shipping. In the power field, the PEM water electrolysis technology can be combined with new energy power such as wind power and photovoltaic power to electrolyze water to produce green hydrogen, and then generate electricity and grid-connect through a hydrogen fuel cell to supply power to the power grid, which helps to solve the problem of large-scale consumption of renewable energy.

[0004] However, the unit cost of the PEM electrolytic cell is much higher than that of the alkaline electrolytic cell, and the unit cost is 4-5 times that of the alkaline electrolytic cell. Among them, the bipolar plate cost accounts for about 53% of the electrolytic cell cost. One of the core problems is the coating cost of the metal plate. At present, the solutions of most suppliers are noble metal coatings such as platinum, iridium, Au, etc. Although they have excellent performance, they are costly and account for 60%-90% of the metal plate cost; while the cost of non-noble metal coatings such as carbon-based is relatively low, but the service life cannot meet the test of the harsh environment of water electrolysis. Therefore, the PEM water electrolysis technology needs to go further in commercialization, and the coating cost and life problems are the prerequisites. Summary of the Invention:

[0005] To solve the above problems, the present invention provides a low-cost coating material for PEM water electrolysis.

[0006] The technical solution of the present invention is realized as follows: It includes a primer layer 2, a high potential resistant layer 3, and a conductive enhancement layer 4. The primer layer 2 is deposited on the upper surface of the substrate 1, the high potential resistant layer 3 is located on the surface of the primer layer 2, and the conductive enhancement layer 4 is located above the high potential resistant layer 3.

[0007] According to another embodiment of the present invention, it further includes that the bottom layer material is one of nickel, nickel alloy, titanium, and titanium alloy. The percentage of nickel atoms in the nickel alloy is 80% - 99%, and the titanium content in the titanium alloy is 90% - 99% in atomic percentage.

[0008] According to another embodiment of the present invention, it further includes that the anti-high potential layer 3 is composed of one or more components of titanium, tantalum, niobium, titanium suboxide (Ti n O2 n-1 , 4≤n≤10), nitrogen, carbon, oxygen, and the titanium suboxide is of the Magneli phase. The contact resistance of the anti-high potential layer 3 under a pressing force of 1.2 MPa is 10 mΩ·cm 2 ~3000 mΩ·cm 2 , and the coating thickness is 5 nm~1000 nm.

[0009] According to another embodiment of the present invention, it further includes that the enhanced conductive layer 4 is composed of one or more of titanium, carbon, tantalum, platinum, gold, iridium, ruthenium, oxygen, nitrogen, wherein the atomic percentage of tantalum is 1%~10%, the atomic percentage of platinum is 10%~50%, the atomic percentage of gold is 1%~5%, the atomic percentage of ruthenium is 1%~10%, the atomic percentage of iridium is 1%~10%, and oxygen can be combined with at least one of titanium, carbon, tantalum, ruthenium, iridium, and the atomic percentage of oxygen is 5%~30%. The contact resistance of the enhanced conductive layer 4 under a pressing force of 1.2 MPa is 1 mΩ·cm 2 ~5 mΩ·cm 2 , and the coating thickness is 5 nm~500 nm.

[0010] According to another embodiment of the present invention, it further includes that when the material composition of the anti-high potential layer 3 contains titanium and oxygen, the oxygen vacancy concentration in the formed titanium oxide is 2%~10%, and the proportion of the anatase structure in the titanium oxide is 80%~100%.

[0011] According to another embodiment of the present invention, it further includes that when the enhanced conductive layer 4 is titanium and oxygen, the oxygen vacancy concentration in the formed titanium oxide is 2%~10%, the coating thickness is 5 nm~10 nm, and the coating thickness can be adjusted by plasma etching.

[0012] According to another embodiment of the present invention, it further includes that the contact resistance of the coating material under a pressing force of 1.2 MPa is 1 mΩ·cm 2 ~5 mΩ·cm 2 , the corrosion potential in a sulfuric acid environment with a pH of 3 containing 0.5 ppm of F ions is -0.1 V~0.5 V, and the corrosion current density is 0.005 μA / cm 2 ~0.08 μA / cm 2 , and the corrosion current density at a potential of 2 V vs. SHE is 0.5 μA / cm 2 ~2 μA / cm 2 .

[0013] In addition, the present application also provides a method for preparing a coating material for low-cost PEM water electrolysis, comprising the following steps:

[0014] (1) Adopt ultrasonic cleaning method, and use an alkaline aqueous cleaning solvent to clean the oil stain on the surface of the substrate and dry it;

[0015] (2) Deposit the underlayer 2, high-potential-resistant layer 3 and enhanced conductive layer 4 by multi-arc ion plating, magnetron sputtering or other common PVD methods;

[0016] (3) Put the cleaned and dried substrate into a PVD vacuum device, close the vacuum chamber door, evacuate the vacuum to 5x10 -3 Pa and then turn on the heating. When the temperature reaches 150°C to 350°C and the pressure is 5x10 -3 Pa, introduce argon into the vacuum chamber, maintain the pressure in the vacuum chamber at 0.2 Pa to 0.5 Pa, turn on the bias voltage, turn on the target power supply, and start depositing the underlayer 2. The coating time is 5 min to 10 min; after completion, keep the pressure in the vacuum chamber unchanged, and start depositing the high-potential-resistant layer 3. When the high-potential-resistant layer 3 contains titanium and oxygen, introduce oxygen with a partial pressure of 1% to 5%; after completion, keep the pressure in the vacuum chamber unchanged, and start depositing the enhanced conductive layer 4; after completion, the argon flow rate can also be increased, maintain the pressure in the vacuum chamber at 1 Pa to 3 Pa, turn on the ion source, set the bias voltage to -600 V to -900 V, and the duty cycle to 50% to 90%, and perform ion etching to control the coating thickness of the enhanced conductive layer 4 to adjust the conductivity of the enhanced conductive layer 4.

[0017] The beneficial effects of the present invention are:

[0018] By coating the coating material on the metal components for water electrolysis, the present invention has the ability to resist high-potential corrosion, can be applied to the water electrolysis application scenario, the coating simultaneously has excellent electrical conductivity, and the coating material used overcomes the problems of insufficient high-potential tolerance of current non-precious metal coatings and too high cost of precious metal coatings. It can not use precious metals or use a small amount of precious metals, and can effectively reduce the cost of coating materials in the field of water electrolysis. Description of the drawings:

[0019] Figure 1 It is a schematic structural diagram of the coating material for low-cost PEM water electrolysis of the present invention.

[0020] In the figure: 1 substrate 1; 2 underlayer 2; 3 high-potential-resistant layer 3; 4 enhanced conductive layer 4. Specific embodiments:

[0021] The following elaborates on the preferred embodiments of the present invention in conjunction with the drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0022] Example 1

[0023] See Figure 1 , a coating material for low-cost PEM water electrolysis, including a primer layer 2, a high potential resistant layer 3, and a conductive enhancement layer 4. The primer layer 2 is deposited on the upper surface of the substrate 1, the high potential resistant layer 3 is located on the surface of the primer layer 2, and the conductive enhancement layer 4 is located above the high potential resistant layer 3. The material of the primer layer 2 is titanium alloy, and the titanium content in the titanium alloy is 95 atomic percentage.

[0024] The high potential resistant layer 3 is tantalum, titanium suboxide (Ti n O 2n-1 , n = 4), and nitrogen. The contact resistance of the high potential resistant layer 3 under a pressing force of 1.2 MPa is 12 mΩ·cm 2 , and the coating thickness is 500 nm.

[0025] The conductive enhancement layer 4 is a composite coating composed of titanium, tantalum, oxygen, and nitrogen. The contact resistance of the conductive enhancement layer 4 under a pressing force of 1.2 MPa is 3 mΩ·cm 2 , and the coating thickness is 30 nm.

[0026] The contact resistance of the multi-layer coating material under a pressing force of 1.2 MPa is 3.5 mΩ·cm 2 , the corrosion potential in a sulfuric acid environment with a pH of 3 containing 0.5 ppm of F ions is 0.2 V, and the corrosion current density is 0.05 μA / cm 2 , and the corrosion current density at a potential of 2 V vs. SHE is 0.82 μA / cm 2 .

[0027] Example 2

[0028] In this example, different from Example 1, the material of the primer layer 2 is nickel alloy, and the nickel content in the nickel alloy is 90 atomic percentage.

[0029] The high potential resistant layer 3 is titanium, oxygen, and nitrogen. The oxygen vacancy concentration in the formed titanium oxide is 5%, and the anatase structure accounts for 80% in the titanium oxide. The contact resistance of the high potential resistant layer 3 under a pressing force of 1.2 MPa is 25 mΩ·cm 2 , and the coating thickness is 1000 nm.

[0030] The conductive enhancement layer 4 is titanium and oxygen. The oxygen vacancy concentration in the formed titanium oxide is 10%, and the anatase structure accounts for 90% in the titanium oxide. The contact resistance of the conductive enhancement layer 4 under a pressing force of 1.2 MPa is 5 mΩ·cm 2 , and the coating thickness is 10 nm.

[0031] The contact resistance of the multi-layer coating material under a pressing force of 1.2 MPa is 6 mΩ·cm 2 , the corrosion potential in a sulfuric acid environment with a pH of 3 containing 0.5 ppm of F ions is 0.35 V, and the corrosion current density is 0.004 μA / cm 2 , the corrosion current density at a potential of 2 V vs. SHE is 0.63 μA / cm 2 .

[0032] Example 3

[0033] In this example, different from Example 2, the enhanced conductive layer 4 is titanium and oxygen, the oxygen vacancy concentration in the formed titanium oxide is 8%, the proportion of anatase structure in the titanium oxide is 85%, and the contact resistance of the enhanced conductive layer 4 under a pressing force of 1.2 MPa is 3.5 mΩ·cm 2 , the coating thickness is 300 nm, and after coating, the coating thickness is etched to 5 nm using plasma etching.

[0034] The contact resistance of the multi-layer coating material under a pressing force of 1.2 MPa is 3.7 mΩ·cm 2 , the corrosion potential in a sulfuric acid environment with a pH of 3 containing 0.5 ppm of F ions is 0.25 V, and the corrosion current density is 0.008 μA / cm 2 , the corrosion current density at a potential of 2 V vs. SHE is 0.75 μA / cm 2 .

[0035] Example 4

[0036] In this example, different from Example 1, the enhanced conductive layer 4 is carbon and ruthenium, and the atomic percentage of ruthenium is 2%. The contact resistance of the enhanced conductive layer 4 under a pressing force of 1.2 MPa is 2 mΩ·cm 2 , and the coating thickness is 150 nm.

[0037] The contact resistance of the multi-layer coating material under a pressing force of 1.2 MPa is 2.1 mΩ·cm 2 , the corrosion potential in a sulfuric acid environment with a pH of 3 containing 0.5 ppm of F ions is 0.5 V, and the corrosion current density is 0.01 μA / cm 2 , the corrosion current density at a potential of 2 V vs. SHE is 0.95 μA / cm 2 .

[0038] Example 5

[0039] In this example, different from Example 1, the enhanced conductive layer 4 is carbon, nitrogen, and oxygen, and the atomic percentage of oxygen is 10%. The contact resistance of the enhanced conductive layer 4 under a pressing force of 1.2 MPa is 3 mΩ·cm2 , the coating thickness is 300 nm.

[0040] The contact resistance of the multi-layer coating material under a pressing force of 1.2 MPa is 3.2 mΩ·cm 2 , the corrosion potential is 0.52 V and the corrosion current density is 0.03 μA / cm² in a sulfuric acid environment with a pH of 3 containing 0.5 ppm of F ions 2 , the corrosion current density is 2 μA / cm² at a potential of 2 V vs. SHE 2 .

Claims

1. A low-cost coating material for PEM water electrolysis, characterized in that: The invention comprises a base layer 2, an anti-high potential layer 3, and an enhanced conductive layer 4, wherein the base layer 2 is deposited on the upper surface of the substrate 1, the anti-high potential layer 3 is located on the surface of the base layer 2, and the enhanced conductive layer 4 is located on the anti-high potential layer 3. The base layer 2 is made of one of nickel, nickel alloy, titanium, and titanium alloy, wherein the atomic percentage of nickel in the nickel alloy is 80% to 99%, and the atomic percentage of titanium in the titanium alloy is 90% to 99%.

2. The low-cost PEM water electrolysis coating material according to claim 1, characterized in that: The anti-high potential layer 3 is made of titanium, tantalum, niobium, titanium oxide (Ti n O 2n-1 , 4≤n≤10), nitrogen, carbon, oxygen or one or more components, the titanium oxide is a Magneli phase. The contact resistance of the high potential resistant layer 3 under a compressive force of 1.2MPa is 10mΩ·cm 2 ~3000mΩ·cm 2 , the coating thickness is 5nm~1000nm.

3. The low-cost PEM water electrolysis coating material according to claim 1, characterized in that: The enhanced conductive layer 4 is one or more of titanium, carbon, platinum, gold, iridium, ruthenium, oxygen, and nitrogen, wherein the atomic percentage of tantalum is 1% to 10%, the atomic percentage of platinum is 10% to 50%, the atomic percentage of gold is 1% to 5%, the atomic percentage of ruthenium is 1% to 10%, and the atomic percentage of iridium is 1% to 10%. Oxygen can be combined with at least one of titanium, carbon, tantalum, ruthenium, and iridium, and the atomic percentage of oxygen is 5% to 30%. The contact resistance of the enhanced conductive layer 4 under a compression force of 1.2 MPa is 1 mΩ·cm 2 ~5mΩ·cm 2 , the coating thickness is 5nm~500nm.

4. The high potential resistant layer 3 according to claim 1, characterized in that: When the coating material composition contains titanium and oxygen, the concentration of oxygen vacancies in the formed titanium oxide is 2% to 10%, and the proportion of anatase structure in the titanium oxide is 80% to 100%.

5. The enhanced conductive layer 4 according to claim 3, characterized in that: When the enhanced conductive layer 4 is titanium and oxygen, the oxygen vacancy concentration in the formed titanium oxide is 2% to 10%, and the coating thickness is 5nm to 10nm. The coating thickness can be controlled by plasma etching.

6. The low-cost PEM water electrolysis coating material according to claim 1, characterized in that: The contact resistance of the coating material under a compression force of 1.2 MPa is 1 mΩ·cm 2 ~5mΩ·cm 2 In a sulfuric acid environment with a pH of 3 and containing 0.5 ppm of F ions, the corrosion potential is -0.1 V to 0.5 V, and the corrosion current density is 0.005 μA / cm 2 ~0.08μA / cm 2 , the corrosion current density is 0.5μA / cm at 2V vs.SHE potential 2 ~2μA / cm 2 .

7. A method for preparing a low-cost coating material for PEM water electrolysis, characterized in that: The following steps are involved: (1) Using ultrasonic cleaning, use alkaline aqueous cleaning solvent to clean the oil stains on the surface of the substrate and dry it; (2) using multi-arc ion plating, magnetron sputtering or other common PVD methods to deposit the base layer 2, the high potential resistance layer 3 and the enhanced conductive layer 4; (3) Place the cleaned and dried substrate into the PVD vacuum equipment, close the vacuum chamber door, and pump the vacuum to 5x10 -3 Pa, heating is turned on. When the temperature reaches 150℃~350℃ and the pressure reaches 5x10 -3 After Pa, argon gas is introduced into the vacuum chamber, the pressure in the vacuum chamber is maintained at 0.2Pa~0.5Pa, the bias is turned on, the target power supply is turned on, and the deposition of the base layer 2 begins, and the coating time is 5min~10min; after completion, the pressure of the vacuum chamber is kept unchanged, and the deposition of the anti-high potential layer 3 begins. When the anti-high potential layer 3 contains titanium and oxygen, the partial pressure of the oxygen introduced is 1%~5%; after completion, the pressure of the vacuum chamber is kept unchanged, and the deposition of the enhanced conductive layer 4 begins; after completion, the argon flow rate can also be increased, the vacuum chamber pressure is maintained at 1Pa~3Pa, the ion source is turned on, the bias is set at -600V~-900V, the duty cycle is 50%~90%, ion etching is performed, and the coating thickness of the enhanced conductive layer 4 is controlled to adjust the conductive properties of the enhanced conductive layer 4.

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