Novel PEM water electrolysis hydrogen production bipolar plate structure, preparation method thereof and electrolytic bath

Abstract

The invention provides a novel PEM water electrolysis hydrogen production bipolar plate structure which is characterized by comprising a bipolar plate body and a protective layer, and the protective layer is formed on the surface of the bipolar plate body and is a conductive diamond layer. The invention provides a preparation method of a novel PEM water electrolysis hydrogen production bipolar plate structure. The preparation method comprises the following steps: S1, providing a bipolar plate body; and S2, growing conductive diamond on the surface of the bipolar plate to obtain the bipolar plate with the conductive diamond layer. In the invention, the conductive diamond provides low-cost anti-oxidation corrosion treatment for the bipolar plate, and the service life of the bipolar plate of the electrolytic cell is prolonged. And the conductive diamond growth layer provides durable conductivity for the bipolar plate, so that the bipolar plate has higher mechanical strength and better gas sealing effect.

Description

Technical Field

[0001] The invention relates to the field of materials for producing hydrogen by electrolyzing water, and in particular to a current collector material for producing hydrogen in a proton exchange membrane electrolyzer. Background Art

[0002] The Proton Exchange Membrane Water Electrolyzer is an efficient and green water electrolysis device for hydrogen production. It will serve as an important energy conversion bridge in the green transformation of economic energy. Due to its fast startup response, low operating temperature and modular stack installation, it is considered to be the earliest type of device for commercializing water electrolysis to produce hydrogen. The core components of the proton exchange membrane electrolyzer are the membrane electrode assembly, gas diffusion layer and bipolar plate. The bipolar plate serves as a current collector and also serves as a mechanical support for the electrolyzer structure. During the electrolysis process, the currently common titanium-based metal is gradually oxidized because the anode maintains a high potential for a long time, causing the contact resistance of the electrolyzer to increase. The oxidized metal surface changes its hydrophilicity and hydrophobicity, which makes it difficult for the electrolyzer to drain water and conduct gas, indirectly causing the deterioration of mass transfer. At present, in order to improve the oxidation resistance of metal bipolar plates, the mainstream approach is to introduce precious metal coatings. However, since the electrolytic cell itself requires more precious metal catalysts, this mainstream approach cannot significantly reduce the precious metal usage of the system. In addition, due to the scarcity of precious metals themselves, the cost of the entire electrolytic cell is very high, and large-scale commercialization is seriously hindered. Summary of the invention

[0003] Based on the above-mentioned problems, it is necessary to provide a diamond-core-shell metal composite catalyst and a preparation method thereof, as well as an electrolytic cell using the diamond-core-shell metal composite catalyst. Conductive diamond, as a corrosion-resistant electrode material, is very suitable for supporting anode catalysts. The use of such carrier technology can significantly reduce the use of precious metals without affecting the electrolysis efficiency, thereby reducing the cost of PEM-WE and realizing a solution for large-scale application.

[0004] A novel PEM water electrolysis hydrogen production bipolar plate structure comprises a bipolar plate body and a protective layer, wherein the protective layer is formed on the surface of the bipolar plate body and is a conductive diamond layer.

[0005] In one embodiment, the substrate of the bipolar plate is one of aluminum, nickel, titanium, tantalum metal or metal alloys thereof or stainless steel.

[0006] In one embodiment, the bipolar plate type is one of a serpentine flow field, an interdigitated flow field, a parallel flow field or a needle flow field.

[0007] In one embodiment, the flow channel width of the bipolar plate is 0.2-2.6 mm.

[0008] In one embodiment, the flow channel angle of the bipolar plate is 80-155°.

[0009] In one embodiment, the width of the flow channel ridge of the bipolar plate is 0.14-2.6 mm.

[0010] In one embodiment, the flow channel depth of the bipolar plate is 0.3-2.1 mm.

[0011] In one embodiment, the growth loading of the conductive diamond layer is 0.05-2 mg / cm 2 , the growth layer thickness is 0.3-5.7μm.

[0012] A novel method for preparing a bipolar plate structure for PEM water electrolysis hydrogen production comprises the following steps:

[0013] S1:

[0014] Providing a bipolar plate body;

[0015] S2:

[0016] Conductive diamond is grown on the surface of the bipolar plate body to obtain a bipolar plate with a conductive diamond layer.

[0017] In one embodiment, in step S2, the growth parameters of the conductive diamond layer are: the number of hot wires is 10 to 24, the hot wire distance is 10 to 17 mm, the distance between the hot wire and the base is 5 to 20 mm, the total flow rate of methane, boron source and hydrogen is 250 to 500 sccm, wherein the flow rate ratio of methane to hydrogen is 1 / 50 to 1 / 1000, the flow rate ratio of boron source to hydrogen is 1 / 50 to 1 / 1000, the gas pressure is 10 to 40 Torr, the hot wire temperature is 1800 to 2400 degrees Celsius, the base temperature is 500 to 900 degrees Celsius, and the growth time is 2 to 20 hours.

[0018] A novel PEM water electrolysis hydrogen production bipolar plate structure is prepared using any of the above-mentioned methods for preparing the novel PEM water electrolysis hydrogen production bipolar plate structure.

[0019] An electrolyzer using the novel PEM water electrolysis hydrogen production bipolar plate structure described in any one of the above items.

[0020] The beneficial effects of the present invention are:

[0021] 1. Provide low-cost anti-oxidation and corrosion treatment for bipolar plates to extend the service life of bipolar plates in electrolyzers.

[0022] 2. The conductive diamond growth layer provides durable conductivity for the bipolar plate, giving the bipolar plate higher mechanical strength and better gas sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 The present invention is a flowchart of a method for preparing a novel bipolar plate structure for producing hydrogen by PEM water electrolysis according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the partial structure of a novel PEM water electrolysis hydrogen production bipolar plate structure according to an embodiment of the present invention.

[0026] Figure 3 A comparison chart of the electrolytic durability of Example 1, Comparative Example 2, and Comparative Example 1 and Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention provides a novel PEM water electrolysis hydrogen production bipolar plate structure, comprising a bipolar plate body and a protective layer, wherein the protective layer is formed on the surface of the bipolar plate body, and the protective layer is a conductive diamond layer. The bipolar plate structure is prepared by the preparation method of the bipolar plate provided by the present invention. In one embodiment, Figure 1 As shown, a novel method for preparing a bipolar plate structure for producing hydrogen by PEM water electrolysis comprises the following steps:

[0029] Step S1:

[0030] A bipolar plate body is provided.

[0031] For example, the substrate of the bipolar plate body is a metal-based material. Further, in one embodiment, the substrate of the bipolar plate body is one of aluminum, nickel, titanium, tantalum metal or its metal alloy or stainless steel. For example, the substrate of the bipolar plate body is aluminum or an aluminum alloy, for example, the substrate of the bipolar plate body is nickel or a nickel alloy, for example, the substrate of the bipolar plate body is stainless steel, and in this embodiment, they are not described one by one.

[0032] For example, a flow channel is formed on the bipolar plate body. Further, in one embodiment, the bipolar plate type is one of a serpentine flow field, an interdigitated flow field, a parallel flow field or a needle flow field.

[0033] Step S2:

[0034] Conductive diamond is grown on the surface of the bipolar plate body to obtain a bipolar plate with a conductive diamond layer.

[0035] The number of the conductive diamond layers can be single layer, double layer or multi-layer.

[0036] In a preferred embodiment, in step S2, before growing conductive diamonds on the surface of the bipolar plate body, the bipolar plate body is surface treated. In one embodiment, step S2 includes: using methanol and acetone in an ultrasonic cleaning tank to clean the plate in sequence, blowing dry with nitrogen after cleaning, sandblasting the plate, placing the plate in a HF-CVD vacuum furnace, biasing nucleation at -20 to -150V for 10 to 120 minutes, growing conductive diamonds on the surface of the bipolar plate body, and obtaining a bipolar plate with a conductive diamond layer. In another embodiment, step S2 includes: using methanol, acetone, and pure water in an ultrasonic cleaning tank to clean the plate in sequence, blowing dry with nitrogen after cleaning, placing the plate in a HF-CVD vacuum furnace, biasing nucleation at -20 to -150V for 10 to 120 minutes, growing conductive diamonds on the surface of the bipolar plate body, and obtaining a bipolar plate with a conductive diamond layer.

[0037] In one embodiment, in step S2, the growth parameters of the conductive diamond layer are: the number of hot wires is 10 to 24, the hot wire distance is 10 to 17 mm, the distance between the hot wire and the base is 5 to 20 mm, the total flow rate of methane, boron source and hydrogen is 250 to 500 sccm, wherein the flow rate ratio of methane to hydrogen is 1 / 50 to 1 / 1000, the flow rate ratio of boron source to hydrogen is 1 / 50 to 1 / 1000, the gas pressure is 10 to 40 Torr, the hot wire temperature is 1800 to 2400 degrees Celsius, the base temperature is 500 to 900 degrees Celsius, and the growth time is 2 to 20 hours.

[0038] The beneficial effects of the present invention are:

[0039] 1. Provide low-cost anti-oxidation and corrosion treatment for bipolar plates to extend the service life of bipolar plates in electrolyzers.

[0040] 2. The conductive diamond growth layer provides durable conductivity for the bipolar plate, giving the bipolar plate higher mechanical strength and better gas sealing effect.

[0041] Bipolar plate physical properties Before growth (pure) After growth (Example 1) After growth (Example 2) Conductivity S / cm 165 158 153 Bending strength MPa 25MPa 32MPa 30MPa <![CDATA[Air permeability cm 3 / cm 2 ·s]]> <![CDATA[2×10 -8 ]]> <![CDATA[1.5×10 -8 ]]> <![CDATA[1.1×10 -8 ]]>

[0042] Table 1

[0043] Table 1 shows the comparison of physical properties of bipolar plates before and after the growth of the conductive diamond layer. 2 Conductive diamond titanium bipolar plate, Example 2 is a 0.2 mg / cm 2 A titanium bipolar plate with conductive diamond, wherein the thickness of the titanium bipolar plate is 0.1 mm.

[0044] After the conductive diamond layer is grown according to this patent, the conductivity of the bipolar plate decreases slightly, but it still maintains a relatively high overall conductivity with a small change in conductivity. The bending strength of the bipolar plate after the conductive diamond layer is significantly improved, while the air permeability decreases, indicating that the bipolar plate after the conductive diamond layer is grown has higher mechanical strength and better gas sealing effect.

[0045] In one embodiment, the flow channel width of the bipolar plate is 0.2-2.6 mm.

[0046] In one embodiment, the flow channel angle of the bipolar plate is 80-155°.

[0047] In one embodiment, the width of the flow channel ridge of the bipolar plate is 0.14-2.6 mm.

[0048] In one embodiment, the flow channel depth of the bipolar plate is 0.3-2.1 mm.

[0049] In one embodiment, the growth loading of the conductive diamond layer is 0.05-2 mg / cm 2 The thickness of the growth layer is 0.3-5.7 μm. The thickness of the growth layer is the overall thickness of the conductive diamond layers. If the number of conductive diamond layers is a single layer, the thickness of the single layer is 0.3-5.7 μm. If the number of conductive diamond layers is multiple layers, the overall thickness of the multiple conductive diamond layers is 0.3-5.7 μm.

[0050] The present invention provides an electrolytic cell using the bipolar plate described in any one of the above embodiments.

[0051] like Figure 3 As shown, it is a comparison chart of the electrolytic durability of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 of the present invention. Among them, Example 1 is a comparison chart of the electrolytic durability of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 of the present invention. 2 Conductive diamond titanium bipolar plate, Example 2 is a 0.2 mg / cm 2 The titanium bipolar plate is made of conductive diamond, wherein the thickness of the titanium bipolar plate is 0.1 mm. Comparative Example 1 is a pure titanium bipolar plate without precious metals, and Comparative Example 2 is 1 mg / cm 2Platinum-plated titanium bipolar plate. Among them, Example 1, Example 2, Comparative Example 1 and Comparative Example 2 all use the same membrane electrode, and the anodic oxide iridium loading is 2 mg Ir / cm 2 , cathode platinum carbon loading 0.4mg Pt / cm 2 The test was conducted at 80 degrees Celsius and a current density of 2.3A / cm.

[0052] See also Figure 3 The test results using the membrane electrode of the same specifications show that the voltage change of the electrolytic cell composed of the bipolar plates of the embodiment of the present invention is less than 12mV after 1000 hours of constant current electrolysis, which is better than the platinum-plated bipolar plate of comparative example 2 (voltage change is less than 24mV) and the pure titanium bipolar plate without precious metal coating of comparative example 1 (voltage change is less than 90mV). The bipolar plate preparation method of the present invention can realize the design of long-life bipolar plates without precious metal coating.

[0053] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A novel bipolar plate structure for PEM water electrolysis hydrogen production, characterized in that: It comprises a bipolar plate body and a protective layer, wherein the protective layer is formed on the surface of the bipolar plate body and is a conductive diamond layer.

2. The novel PEM water electrolysis hydrogen production bipolar plate structure according to claim 1 is characterized in that: The substrate of the bipolar plate is one of aluminum, nickel, titanium, tantalum metal or metal alloys thereof or stainless steel.

3. The novel PEM water electrolysis hydrogen production bipolar plate structure according to claim 1 is characterized in that: The bipolar plate type is one of a serpentine flow field, an interdigitated flow field, a parallel flow field or a needle flow field.

4. The novel PEM water electrolysis hydrogen production bipolar plate structure according to claim 1 is characterized in that: The flow channel width of the bipolar plate is 0.2-2.6 mm.

5. The novel PEM water electrolysis hydrogen production bipolar plate structure according to claim 1 is characterized in that: The flow channel angle of the bipolar plate is 80-155°.

6. The novel PEM water electrolysis hydrogen production bipolar plate structure according to claim 1 is characterized in that: The width of the flow channel ridge of the bipolar plate is 0.14-2.6 mm.

7. The novel PEM water electrolysis hydrogen production bipolar plate structure according to claim 1 is characterized in that: The flow channel depth of the bipolar plate is 0.3-2.1 mm.

8. The novel PEM water electrolysis hydrogen production bipolar plate structure according to claim 1 is characterized in that: The growth loading of the conductive diamond layer is 0.05-2mg / cm 2 , the growth layer thickness is 0.3-5.7μm.

9. A novel method for preparing a bipolar plate structure for PEM water electrolysis hydrogen production, characterized in that: The steps include: S1： Providing a bipolar plate body; S2： Conductive diamond is grown on the surface of the bipolar plate body to obtain a bipolar plate with a conductive diamond layer.

10. The method for preparing the novel PEM water electrolysis hydrogen production bipolar plate structure according to claim 9, characterized in that: In the step S2, the growth parameters of the conductive diamond layer are: the number of hot wires is 10 to 24, the hot wire distance is 10 to 17 mm, the distance between the hot wire and the base is 5 to 20 mm, the total flow rate of methane, boron source and hydrogen is 250 to 500 sccm, wherein the flow rate ratio of methane to hydrogen is 1 / 50 to 1 / 1000, the flow rate ratio of boron source to hydrogen is 1 / 50 to 1 / 1000, the gas pressure is 10 to 40 Torr, the hot wire temperature is 1800 to 2400 degrees Celsius, the base temperature is 500 to 900 degrees Celsius, and the growth time is 2 to 20 hours.

11. A novel bipolar plate structure for PEM water electrolysis to produce hydrogen, characterized in that: The method for preparing a bipolar plate with a conductive diamond layer according to any one of claims 1 to 10 is used to prepare the bipolar plate.

12. An electrolytic cell, characterized in that: A novel PEM water electrolysis hydrogen production bipolar plate structure is used as described in any one of claims 1-11.

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