Sealing ring for electrolytic bath and preparation method of sealing ring

Abstract

The invention belongs to the technical field of polymer sealing materials, and particularly relates to a sealing ring for an electrolytic bath and a preparation method of the sealing ring. Surface anchoring holes are formed in the metal framework ring at intervals so that the fluororubber wrapping layer can penetrate through the surface anchoring holes. The fluororubber wrapping layer comprises the following components in parts by mass: 55 parts of hydrogenated butadiene-acrylonitrile rubber, 45 parts of fluororubber, 20-30 parts of gas-phase SiO2, 4-8 parts of carbon nanotubes, 1-3 parts of an anti-aging agent, 2.5-3.5 parts of a peroxide vulcanizing agent, 3-5 parts of an assistant crosslinking agent, 1-3 parts of a crosslinking agent, 3-8 parts of an acid absorbent and 0.5-2 parts of a processing aid.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer sealing materials, and particularly relates to a sealing ring for an electrolytic cell and a preparation method thereof. Background Art

[0002] Against the backdrop of the rapid development of the hydrogen energy industry, proton exchange membrane (PEM) water electrolysis hydrogen production technology has become one of the key directions in hydrogen production due to its advantages such as high efficiency, cleanliness, and fast system response. As a core equipment, the safety and sealing of the PEM electrolyzer are particularly important under high-pressure operating conditions (such as 35MPa). As a key component of the electrolyzer, rubber sealing rings must operate under multiple harsh conditions such as high pressure, water environment, electric field, and chemical corrosion for a long time. Therefore, extremely high requirements are placed on their material properties, especially in terms of pressure resistance, corrosion resistance, sealing stability, and dimensional stability.

[0003] Traditional rubber materials are prone to permeation in high-voltage electrolysis environments, leading to chemical degradation, and then permanent compression deformation, causing seal failure, making it difficult to meet the application requirements of modern high-performance electrolyzers.

[0004] Therefore, how to overcome the defect that the sealing ring is easily penetrated under high pressure conditions of 35 MPa is a technical problem that needs to be solved urgently in this field.

[0005] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the Invention

[0006] The embodiments of the present disclosure at least provide a sealing ring for an electrolytic cell and a preparation method thereof.

[0007] In a first aspect, an embodiment of the present disclosure provides a sealing ring for an electrolytic cell, comprising: a metal skeleton ring and a fluororubber wrapping layer; surface anchor holes are spaced apart on the metal skeleton ring to allow the fluororubber wrapping layer to pass through; the fluororubber wrapping layer comprises the following components in parts by mass: 55 parts of hydrogenated nitrile rubber, 45 parts of fluororubber, 20-30 parts of gas-phase SiO2, 4-8 parts of carbon nanotubes, 1-3 parts of an anti-aging agent, 2.5-3.5 parts of a peroxide vulcanizing agent, 3-5 parts of a cross-linking aid, 1-3 parts of a cross-linking agent, 3-8 parts of an acid absorbent, and 0.5-2 parts of a processing aid.

[0008] In an optional embodiment, the fluororubber wrapping layer on the inner wall side of the metal skeleton ring is provided with a main lip and a secondary lip; the main lip protrudes radially, one side of the secondary lip is the inner lip surface of the main lip, and the other side is the inner wall of the fluororubber wrapping layer.

[0009] In an optional embodiment, the inner wall of the metal skeleton ring and the fluororubber wrapping layer form a dynamic pressure compensation groove under pressure extrusion of the main lip; the groove cross-section of the dynamic pressure compensation groove is any one of a wedge shape, a wave shape or a spiral shape.

[0010] In an optional embodiment, the contact surface between the metal skeleton ring and the fluororubber wrapping layer is provided with either a friction-reducing texture or a coating.

[0011] In an optional embodiment, the hydrogenation degree of the hydrogenated nitrile rubber is not less than 94%, the acrylonitrile content is not less than 34%, and the Mooney viscosity ML (1+4) at 100°C is 40-60; the fluororubber includes vinylidene fluoride-hexafluoropropylene copolymer fluororubber, and the fluorine content is not less than 66%.

[0012] In an optional embodiment, the acid absorbent includes highly active magnesium oxide; and the processing aid includes perfluoropolyether oil.

[0013] In the second aspect, the embodiment of the present disclosure also provides a preparation method of the sealing ring for the electrolytic cell as described above, comprising the following steps: S1, internal mixing, mixing hydrogenated nitrile rubber, fluororubber, gas-phase SiO2, carbon nanotubes, anti-aging agent, processing aid and acid absorbent, controlling the temperature below 95°C to obtain an internal mixing material; S2, mixing, adding peroxide vulcanizing agent, auxiliary cross-linking agent and cross-linking agent to the internal mixing material at 40-60°C, mixing, and tableting to obtain a mixed material; S3, molding, completing molding on a metal skeleton ring at 160-170°C and an injection pressure of 100-120MPa; S4, two-stage vulcanization, first keeping the molded mixed material at 170-175°C for 10-15 minutes for main vulcanization, and then slowly heating it at 200-220°C and maintaining it for 4-8 hours for post-vulcanization to obtain a vulcanized material; S5, post-treatment, plasma surface treatment of the vulcanized material to obtain a sealing ring for the electrolytic cell.

[0014] In an optional embodiment, the gas-phase SiO2 is hydrophobic gas-phase silica modified with a silane coupling agent, with a particle size range of 7 to 40 nm and a specific surface area range of 200 to 300 m2 / g; the preparation method of the gas-phase SiO2 includes: burning SiCl4 vapor with hydrogen and oxygen at 1200 to 1600°C to generate nano-scale SiO2 particles, and after cyclone separation and deacidification, surface modification with a silane coupling agent to obtain gas-phase SiO2.

[0015] In an optional embodiment, the carbon nanotubes have a particle size range of 10 to 20 nm and a length range of 10 to 30 μm; the method for preparing the carbon nanotubes comprises: decomposing methane or ethylene at 600 to 900° C. over an iron / cobalt / nickel catalyst to generate a crude product of multi-walled or single-walled carbon nanotubes, and washing the crude product with a mixture of concentrated nitric acid and sulfuric acid and purifying it by ultrasonic dispersion to obtain the carbon nanotubes.

[0016] In a third aspect, an embodiment of the present disclosure further provides an electrolytic cell, which uses the sealing ring for the electrolytic cell as described above, and the electrolytic cell includes any one of an AEM electrolytic cell and a PEM electrolytic cell.

[0017] The beneficial effect of the present invention is that the sealing ring for the electrolytic cell and the preparation method thereof use a composite of hydrogenated nitrile rubber and fluororubber as the base material to meet the basic requirements of high temperature resistance, chemical corrosion resistance, and low gas permeability. At the same time, the compressive strength and long-term sealing stability are improved through synergistic reinforcement by gas-phase SiO2, and a peroxide vulcanizing agent is used for vulcanization cross-linking to form a dense cross-linked network, ensuring resistance to compression deformation and low precipitation characteristics. In the dynamic pressure compensation groove formed after being pressurized, the elastic force brought by its elastic deformation and the external pressure offset each other, meeting the low permeability and high reliability requirements of the electrolytic cell for the sealing ring.

[0018] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A physical picture of a sealing ring for an electrolytic cell provided in an embodiment of the present disclosure;

[0022] Figure 2 A schematic structural diagram of a sealing ring for an electrolytic cell provided in an embodiment of the present disclosure;

[0023] Figure 3Partial cross-sectional views of a sealing ring for an electrolytic cell provided in an embodiment of the present disclosure, (a) is a schematic diagram of the static structure, and (b) is a schematic diagram of the compressed structure;

[0024] Figure 4 Pressure distribution diagrams of a sealing ring for an electrolytic cell before (A) and after (B) compression provided by an embodiment of the present disclosure.

[0025] In the picture:

[0026] 1. Metal skeleton ring; 2. Fluororubber wrapping layer; 3. Surface anchor hole; 4. Main lip; 5. Auxiliary lip; 6. Dynamic pressure compensation groove. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations, aspects, or designs. Instead, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0029] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." when following a list of elements modify the entire list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0030] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an" and "the" may also be intended to include plural forms, unless otherwise clearly indicated herein. The terms "comprise", "include" and "have" are inclusive and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the particular order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0031] In this article, PEM (Proton Exchange Membrane) electrolyzer is a proton exchange membrane electrolyzer; AEM (Anion Exchange Membrane) electrolyzer is an anion exchange membrane electrolyzer.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0033] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0034] See also Figure 1-Figure 3 ,like Figure 1-Figure 3 As shown, an embodiment of the present disclosure provides a sealing ring for an electrolytic cell, comprising: a metal skeleton ring and a fluororubber wrapping layer; surface anchoring holes are spaced apart on the metal skeleton ring to allow the fluororubber wrapping layer to pass through; the fluororubber wrapping layer comprises the following components in parts by mass: 55 parts of hydrogenated nitrile rubber, 45 parts of fluororubber, 20-30 parts of gas-phase SiO2, 4-8 parts of carbon nanotubes, 1-3 parts of an anti-aging agent, 2.5-3.5 parts of a peroxide vulcanizing agent, 3-5 parts of a cross-linking aid, 1-3 parts of a cross-linking agent, 3-8 parts of an acid absorbent, and 0.5-2 parts of a processing aid.

[0035] In some embodiments, specifically, the fluororubber wrapping layer on the inner wall side of the metal skeleton ring is provided with a main lip and a secondary lip; the main lip protrudes radially, one side of the secondary lip is the inner lip surface of the main lip, and the other side is the inner wall of the fluororubber wrapping layer.

[0036] See also Figure 3 ,like Figure 3As shown, specifically, the inner wall of the metal skeleton ring and the fluororubber wrapping layer form a dynamic pressure compensation groove when the main lip is squeezed by pressure; the groove cross-section of the dynamic pressure compensation groove is any one of a wedge shape, a wave shape or a spiral shape. After the main lip and the auxiliary lip are squeezed by upper and lower pressures, the dynamic pressure compensation groove formed does not disappear under high-pressure environment, indicating that the elastic force brought by the elastic deformation and the external pressure offset each other, further improving the sealing performance of the sealing ring.

[0037] See also Figure 4 ,like Figure 4 Specifically, the fluoroelastomer sheath and the metal ring form a mechanical interlocking mechanism under high temperature and pressure. The double-lip design allows the buffer flange to undergo radial elastic deformation during pressure increases, creating a transient vacuum gap of 0.5-2mm between the metal ring and the seal body. When pressure decreases, the shape memory polymer (SMP) in the rubber acts as a "molecular spring," generating a rebound pressure of 0.3-1MPa. This dynamic balancing mechanism reduces the peak stress of the main sealing lip by 32-35%. In a 35MPa pulse pressure test, the lip maintained a rebound rate of 89-92% after 5 million cycles.

[0038] In some embodiments, specifically, the contact surface between the metal skeleton ring and the fluororubber wrapping layer is provided with either a friction-reducing texture or a coating.

[0039] In some embodiments, specifically, the hydrogenation degree of the hydrogenated nitrile rubber is not less than 94%, the acrylonitrile content is not less than 34%, and the Mooney viscosity ML (1+4) at 100°C is 40-60; the fluororubber includes vinylidene fluoride-hexafluoropropylene copolymer fluororubber, and the fluorine content is not less than 66%.

[0040] In some embodiments, specifically, the acid absorbent includes highly active magnesium oxide; and the processing aid includes perfluoropolyether oil.

[0041] The embodiment of the present disclosure also provides a preparation method of the sealing ring for the electrolytic cell as described above, comprising the following steps: S1, banburying, mixing hydrogenated nitrile rubber, fluororubber, gas-phase SiO2, carbon nanotubes, anti-aging agent, processing aid and acid absorbent, controlling the temperature below 95°C to obtain a banburying material; S2, mixing, adding a peroxide vulcanizing agent, a co-crosslinking agent and a crosslinking agent to the banburying material at 40-60°C, mixing, and tableting to obtain a mixed material; S3, molding, completing molding on a metal skeleton ring at 160-170°C and an injection pressure of 100-120 MPa; S4, two-stage vulcanization, first keeping the molded mixed material at 170-175°C for 10-15 minutes for main vulcanization, and then slowly heating it at 200-220°C and maintaining it for 4-8 hours for post-vulcanization to obtain a vulcanized material; S5, post-treatment, performing plasma surface treatment on the vulcanized material to obtain a sealing ring for the electrolytic cell.

[0042] In some embodiments, specifically, the gaseous SiO2 is hydrophobic gaseous silica modified with a silane coupling agent, with a particle size range of 7 to 40 nm and a specific surface area range of 200 to 300 m2 / g; the preparation method of the gaseous SiO2 includes: burning SiCl4 vapor with hydrogen and oxygen at 1200 to 1600°C to generate nano-scale SiO2 particles, and after cyclone separation and deacidification, surface modification with a silane coupling agent to obtain gaseous SiO2.

[0043] In some embodiments, specifically, the carbon nanotubes have a particle size range of 10 to 20 nm and a length range of 10 to 30 μm; the method for preparing the carbon nanotubes comprises: decomposing methane or ethylene at 600 to 900° C. over an iron / cobalt / nickel catalyst to generate a crude product of multi-walled or single-walled carbon nanotubes, and washing the crude product with a mixture of concentrated nitric acid and sulfuric acid and purifying it by ultrasonic dispersion to obtain carbon nanotubes.

[0044] An embodiment of the present disclosure further provides an electrolytic cell, which uses the sealing ring for the electrolytic cell as described above, and the electrolytic cell includes any one of an AEM electrolytic cell and a PEM electrolytic cell.

[0045] In this embodiment, specifically, the information of each component is as follows:

[0046] Hydrogenated nitrile rubber: degree of hydrogenation (94%), Mooney viscosity ML (1+4) at 100° C. between 40-60, acrylonitrile content of about 34%; purchased from Shanghai Zannan Technology Co., Ltd., ZN-35158.

[0047] Fluororubber: Vinylidene fluoride-hexafluoropropylene copolymer fluororubber (FKM, G-801, Daikin, Japan), fluorine content 66%, resistant to strong acid and oxidizing media and low gas permeability. Hydrogenated nitrile rubber and fluororubber are preferably blended in a ratio of 55:45 as the matrix material.

[0048] The reinforcing filler is hydrophobic gas-phase SiO2 (Aerosil R812, Evonik, Germany, with a specific surface area of ​​about 260m 2 / g, particle size about 12nm) and plasma surface-modified carbon nanotubes (CNTs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, diameter 10-20nm, length 10-30μm, conductivity >100S / cm).

[0049] Perfluoropolyether oil (Fomblin Y-LVAC 06 / 6, Solvay, Belgium, molecular weight approximately 3,000 g / mol, viscosity approximately 30 cSt) was selected as a processing aid to improve fluidity.

[0050] The vulcanization system includes di-tert-butyl peroxide (DCP, Shanghai Macklin, purity ≥98%), triallyl isocyanurate (TAIC, Mitsubishi Chemical, Japan), and trimethylolpropane triacrylate (TMPTMA, Sartomer, France), preferably added in amounts of 3 phr, 4 phr, and 2 phr, respectively, to construct a high-temperature resistant cross-linked network; 5 phr of highly active magnesium oxide (150 mesh, Kyowa Chemical, Japan) is also preferably added as an acid acceptor.

[0051] A sealing ring for an electrolytic cell, the raw materials used in its preparation and their corresponding weights are shown in Table 1, and the sealing ring is prepared by the following steps:

[0052] (1) preparing HBNR, FKM, fumed SiO2, CNTs, DCP, TAIC, TMPTMA, and MgO according to the ratio;

[0053] (2) In the mixing process, an internal mixer (2L or more) is first used for the internal mixing stage. The temperature is controlled below 95°C to prevent pre-crosslinking. The total mixing time is about 8–10 minutes.

[0054] The specific operation sequence is:

[0055] Put ZN-35158 and G-801 into internal mixer and plasticize for 2 minutes to form a basic mixture;

[0056] Add SiO2 and PFPE oil in two batches, mixing for 2 minutes between each batch to ensure that the filler is fully wetted;

[0057] Add pre-dispersed CNTs (solvent or masterbatch form) in small amounts and multiple additions;

[0058] Add acid absorbent MgO and mix evenly;

[0059] Finally, quickly add DCP, TAIC, and TMPTMA, mix thoroughly, and immediately dispense the rubber to avoid pre-vulcanization. Then, perform open milling and finishing, controlling the temperature at 40–60°C and the sheeting thickness at 4–6 mm to ensure that the filler does not agglomerate, the surface of the rubber is uniform, and it does not stick to the rollers.

[0060] (3) The vulcanization process is divided into compression vulcanization and two-stage post-vulcanization: the main vulcanization temperature is 170–175°C, the time is 10–15 minutes (adjusted according to the thickness), and the pressure is 10–15 MPa; the post-vulcanization adopts a gradual temperature increase (200°C 2h → 220°C 4h, a total of 4–8 hours) to eliminate residues, strengthen the cross-linking network, and improve compression recovery performance.

[0061] Table 1

[0062]

[0063]

[0064] Test method: Compression set test is carried out in accordance with ISO 815-1:2008. The sample is compressed by 25% at room temperature (23±2℃) or high temperature, and the residual deformation is measured after 24 hours.

[0065]

[0066] where t0, t r and t s are the initial, recovered and compressed thicknesses respectively. This method is suitable for evaluating the elastic recovery properties of rubber materials.

[0067] Test results: compression set at 35MPa.

[0068] Table 2

[0069]

[0070]

[0071] Analysis of data from 27 orthogonal experiments revealed that the synergistic reinforcement system of CNTs and SiO2 significantly improves the performance of HNBR / FKM rubber composites. Increasing the CNT addition from 4 to 8 phr significantly increased tear strength, from 22.0 kN / m to a maximum of 27.3 kN / m. Simultaneously, compression set decreased from 26% to a minimum of 18%, demonstrating excellent elastic recovery.

[0072] Increasing the content of gas-phase SiO2 within the range of 20 to 30 phr helps to further enhance the hardness of the material, making the Shore A hardness reach above 90, meeting the rigidity requirements of high-pressure sealing rings.

[0073] In addition, increasing the dosage of DCP as a peroxide curing agent from 2.5phr to 3.5phr can effectively increase the crosslinking density and further reduce the compression set rate.

[0074] The formula with the best comprehensive performance is concentrated in the combination of 8phr of CNTs, 30phr of SiO2, and 3.5phr of DCP. This formula not only has high tear strength and low compression permanent deformation rate, but also has excellent hardness and overall mechanical properties, meeting the use requirements of the high-requirement sealing environment of 35MPa electrolytic cells.

[0075] Specifically, the sealing ring for the electrolytic cell can meet the use requirements of the high-requirement sealing environment of the 35MPa electrolytic cell, but is also applicable in environments below 35MPa and 35-50MPa.

[0076] In summary, the sealing ring for the electrolytic cell and its preparation method use a composite of hydrogenated nitrile rubber and fluororubber as the base material to meet the basic requirements of high temperature resistance, chemical corrosion resistance, and low gas permeability. At the same time, the compressive strength and long-term sealing stability are improved through synergistic reinforcement by gas-phase SiO2. A peroxide vulcanizing agent is used for vulcanization cross-linking to form a dense cross-linked network, ensuring resistance to compression deformation and low precipitation characteristics. In the dynamic pressure compensation groove formed after being pressurized, the elastic force brought by the elastic deformation and the external pressure offset each other, meeting the low permeability and high reliability requirements of the electrolytic cell for the sealing ring.

[0077] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A sealing ring for an electrolytic cell, characterized in that: include: Metal skeleton ring and fluororubber wrapping layer; Surface anchor holes are provided at intervals on the metal skeleton ring to allow the fluororubber wrapping layer to pass through; The fluororubber wrapping layer comprises the following components in parts by mass: 55 parts of hydrogenated nitrile rubber, 45 parts of fluororubber, 20-30 parts of gas-phase SiO2, 4-8 parts of carbon nanotubes, 1-3 parts of anti-aging agent, 2.5-3.5 parts of peroxide vulcanizing agent, 3-5 parts of co-crosslinking agent, 1-3 parts of crosslinking agent, 3-8 parts of acid absorbent, and 0.5-2 parts of processing aid.

2. The sealing ring for electrolytic cell according to claim 1, wherein: The fluororubber wrapping layer on the inner wall side of the metal skeleton ring is provided with a main lip and an auxiliary lip; The main lip protrudes radially, one side of the auxiliary lip is the inner lip surface of the main lip, and the other side is the inner wall of the fluororubber wrapping layer.

3. The sealing ring for electrolytic cell according to claim 2, wherein: The inner wall of the metal skeleton ring and the fluororubber wrapping layer form a dynamic pressure compensation groove when the main lip is squeezed by pressure; The groove cross-section of the dynamic pressure compensation groove is any one of a wedge shape, a wave shape or a spiral shape.

4. The sealing ring for electrolytic cell according to claim 1, wherein: The contact surface between the metal skeleton ring and the fluororubber wrapping layer is provided with either a friction-reducing texture or a coating.

5. The sealing ring for electrolytic cell according to claim 1, wherein: The hydrogenation degree of the hydrogenated nitrile rubber is not less than 94%, the acrylonitrile content is not less than 34%, and the Mooney viscosity ML (1+4) at 100° C. is 40 to 60; The fluororubber includes vinylidene fluoride-hexafluoropropylene copolymer fluororubber, and the fluorine content is not less than 66%.

6. The sealing ring for electrolytic cell according to claim 1, wherein: The acid absorbent includes high-activity magnesium oxide; and the processing aid includes perfluoropolyether oil.

7. A method for preparing a sealing ring for an electrolytic cell according to any one of claims 1 to 6, characterized in that: The steps include: S1, banburying, mixing hydrogenated nitrile rubber, fluororubber, fumed SiO2, carbon nanotubes, anti-aging agent, processing aid and acid absorbent, controlling the temperature below 95°C to obtain banburying material; S2, mixing, adding a peroxide vulcanizing agent, a co-crosslinking agent and a crosslinking agent to the banburying material at 40-60° C., mixing, and tableting to obtain a mixed material; S3, molding, completing molding on the metal skeleton ring at 160-170°C and injection pressure 100-120 MPa; S4, two-stage vulcanization, the formed mixed material is first kept at 170-175℃ for 10-15 minutes for main vulcanization, and then slowly heated to 200-220℃ and maintained for 4-8 hours for post-vulcanization to obtain a vulcanized material; S5, post-processing, subjecting the sulfide material to plasma surface treatment to obtain a sealing ring for the electrolytic cell.

8. The preparation method according to claim 7, wherein The gas-phase SiO2 is a hydrophobic gas-phase silica modified by a silane coupling agent, with a particle size range of 7 to 40 nm and a specific surface area range of 200 to 300 m2 / g; The preparation method of the gas-phase SiO2 comprises: SiCl4 vapor is burned with hydrogen and oxygen at 1200-1600℃ to generate nano-sized SiO2 particles. After cyclone separation and deacidification, the surface is modified with a silane coupling agent to obtain gas-phase SiO2.

9. The preparation method according to claim 7, wherein The carbon nanotubes have a particle size range of 10 to 20 nm and a length range of 10 to 30 μm; The method for preparing the carbon nanotubes comprises: Methane or ethylene is decomposed at 600-900°C over an iron / cobalt / nickel catalyst to generate a crude product of multi-walled or single-walled carbon nanotubes. The crude product is then acid-washed with a mixture of concentrated nitric acid and sulfuric acid and purified by ultrasonic dispersion to obtain carbon nanotubes.

10. An electrolytic cell, characterized in that: The sealing ring for an electrolytic cell according to any one of claims 1 to 6 is used, wherein the electrolytic cell comprises any one of an AEM electrolytic cell and a PEM electrolytic cell.

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