A high-strength electrode sheet, its preparation method and application

Abstract

This invention belongs to the field of electrolysis technology, specifically relating to a high-strength electrode sheet, its preparation method, and its application. The electrode sheet of this invention comprises n base layers, n-1 resin carbon layers, a first microporous layer, and a second microporous layer; the electrode sheet, from top to bottom, consists of: a first microporous layer, a first base layer, a first resin carbon layer, a second base layer, a second resin carbon layer, ..., an n-1th base layer, an n-1th resin carbon layer, an nth base layer, and a second microporous layer, where n is a value between 3 and 10. This invention, by filling the interior and spaces between the base layers with resin carbon, cleverly designs multiple carbon papers to form a carbon paper suitable for the electrolytic synthesis of hydrogen peroxide, possessing high strength, high conductivity, and high air permeability. Simultaneously, by designing a dense microporous layer coating on both sides, the water resistance of the electrode sheet is further improved while ensuring oxygen diffusion capacity, thus making it suitable for the electrolytic synthesis of hydrogen peroxide.

Description

Technical Field

[0001] This invention belongs to the field of electrolysis technology, specifically relating to a high-strength electrode sheet, its preparation method, and its application. Background Technology

[0002] Electrolytic synthesis of hydrogen peroxide has attracted much attention due to its potential for green and decentralized production. As the core component determining oxygen mass transfer and reaction efficiency, the technological innovation of the cathode electrode is crucial to driving the development of this field. Existing technologies mainly focus on resolving the contradiction between the transport of reactants (oxygen) and products (hydrogen peroxide) by optimizing the structure and materials of the electrode.

[0003] The invention patent with publication number CN117684190A provides a method for highly efficient electro-generation of hydrogen peroxide. This method uses an aerated conductive porous membrane as the cathode and the anode as an auxiliary electrode in an electrochemical system. Oxygen-containing gas is continuously introduced into the aerated conductive porous membrane, allowing it to diffuse through the membrane's internal cavity and porous structure to the electrolyte outside the membrane for aeration. Hydrogen peroxide is then electro-generated in the electrolyte via an electrocatalytic reaction. By using the aerated conductive porous membrane as the cathode and introducing oxygen-containing gas from within, the method integrates gas-liquid mass transfer and electrocatalytic reaction, resulting in high oxygen mass transfer efficiency, good mechanical strength, and solving the problem of poor stability in traditional aeration electrodes.

[0004] While the aforementioned traditional electrode sheets can provide a gas-liquid-solid three-phase interface, they face the fundamental contradiction of insufficient oxygen supply and the further reaction or decomposition of the generated H2O2. The decomposition of hydrogen peroxide produces OH-. － The presence of -OH groups can cause the hydrophobicity of traditional electrode sheets to fail, leading to hydrophilicity at the cathode and blocking oxygen diffusion. When the material becomes hydrophilic, its mechanical strength is insufficient to withstand the high water pressure during electrolysis. To resolve this contradiction, the industry uses a method of pressing two flexible, dense, waterproof, and breathable membranes together on both sides of a nickel mesh with a certain mechanical strength. While this solution addresses both waterproofing and mechanical performance, the dense structure results in poor oxygen diffusion and low efficiency. Furthermore, after prolonged electrolysis, hydrogen evolution can occur at the cathode.

[0005] Managing the oxygen diffusion capacity, mechanical strength, and water resistance of the cathode is of paramount importance in the electrolytic synthesis of hydrogen peroxide. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high-strength electrode sheet, its preparation method, and its application. This invention cleverly uses resin carbon to fill the interior and spaces between the substrate layers, forming multiple sheets of carbon paper suitable for high-strength, high-conductivity, and high-permeability electrolytic synthesis of hydrogen peroxide. Furthermore, by designing a dense microporous layer on both sides, the water resistance of the electrode sheet is further improved while ensuring oxygen diffusion capacity, thus making it suitable for electrolytic synthesis of hydrogen peroxide or electrolytic water.

[0007] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows:

[0008] In a first aspect, embodiments of the present invention provide a method for preparing an electrode sheet with high strength, comprising the following steps:

[0009] Step S1, Stacking of base paper: Cut multiple sheets of high-grammage carbon fiber paper and stack them neatly;

[0010] Step S2, Impregnation treatment: The multiple sheets of carbon fiber paper stacked neatly in step S1 are immersed in the impregnation solution for impregnation.

[0011] Step S3, Pulping Treatment: Multiple sheets of carbon fiber paper impregnated with resin solution are placed into pulping rollers for rolling, and the weight gain is controlled to be 150-300% of the total basis weight of the carbon fiber paper;

[0012] Step S4, Drying and Shaping: The carbon fiber paper after liquid injection is dried at a temperature of 80-110℃ for 30-60 minutes to achieve surface dryness.

[0013] Step S5, Curing and Thickness Limiting: Place the carbon fiber paper dried in step S4 into a flatbed hot press for curing.

[0014] Step S6, Cooling and Shaping: After curing is complete, remove the cooled and shaped material to obtain the carbon paper precursor;

[0015] Step S7, High-temperature heat treatment: The carbon paper precursor obtained in step S6 is placed in a carbonization and graphitization furnace for high-temperature heat treatment. The carbonization temperature is 1000-1100℃ and the holding time is 30-60 minutes; the graphitization temperature is 2400-2800℃ and the holding time is 30-60 minutes.

[0016] Step S8, Cutting: After heat treatment, the paper is cooled and cut to form carbon paper;

[0017] Step S9, Hydrophobic treatment: The carbon paper described in step S8 is placed in a polytetrafluoroethylene solution for hydrophobic treatment, and then dried.

[0018] Step S10, High-temperature sintering: Place the carbon paper impregnated with polytetrafluoroethylene into a high-temperature furnace for programmed heating. Increase the temperature from room temperature to 240°C at a rate of 5-10°C / min, hold for 30-60 min, and continue heating at a rate of 5-10°C / min to 350-400°C. Sinter at high temperature for 30-60 min.

[0019] Step S11, microporous layer coating: The microporous layer slurry is uniformly coated onto one side of the hydrophobic carbon paper, and then dried to form the first microporous layer. After drying, the microporous layer slurry is coated on the other side to form the second microporous layer, thus forming a dense microporous layer on both sides of the carbon paper.

[0020] Step S12, Sintering treatment: Place the coated sample into a high-temperature furnace for programmed heating, raising the temperature from room temperature to 240°C at a rate of 5-10°C / min, holding for 30-60 min, and continuing to raise the temperature to 350-400°C at a rate of 5-10°C / min, and sintering at high temperature for 30-60 min.

[0021] Step S13, Sample Completion: After cooling, the electrode sheet is obtained;

[0022] In step S1, the number of sheets of carbon fiber paper is 3-10;

[0023] In step S2, the impregnation solution comprises phenolic resin and a conductive medium, wherein the mass ratio of the phenolic resin to the conductive medium is 70-90:30-10, and the conductive medium is one or more combinations of graphite powder, graphene, and acetylene black.

[0024] Furthermore, in step S1, the basis weight of the carbon fiber paper is 30-50 g / m³. 2 Thickness is 300-800μm@25KPa.

[0025] Furthermore, in step S5, the pressure of the flatbed hot press is set to 3-5 MPa, the temperature to 150-180℃, the holding time to 3-8 minutes, and the final thickness of the cured paper is controlled to be 500-2000 μm.

[0026] Further, in step S9, the mass concentration of the polytetrafluoroethylene solution is 10-15%, and the mass fraction of polytetrafluoroethylene in the carbon paper is 15-30% of the carbon paper basis weight.

[0027] Further, in step S11, the microporous layer slurry is composed of a conductive medium, polytetrafluoroethylene, carbon nanotubes, surfactant, and deionized water, with a mass ratio of 10-15:20-30:10-15:1-1.5:200-300.

[0028] The conductive medium is one or more of XC-72R, acetylene black, graphene, and graphite powder.

[0029] The wet thickness of the first and second microporous layers is 90-150 μm.

[0030] In a second aspect, embodiments of the present invention provide an electrode sheet with high strength, which is prepared by the preparation method described in the first aspect. The electrode sheet includes n base layers, n-1 resin carbon layers and two microporous layers.

[0031] The electrode sheet consists of, from top to bottom, a first microporous layer, a first substrate layer, a first resin carbon layer, a second substrate layer, a second resin carbon layer, ..., an (n-1)th substrate layer, an (n-1)th resin carbon layer, an nth substrate layer, and a second microporous layer, where the value of n is 3-10.

[0032] Furthermore, the overall thickness of the electrode sheet is 450-2000 μm.

[0033] Furthermore, the substrate layer comprises conductive carbon fiber, resin carbon, conductive dielectric and hydrophobic layer, and the pore size of the substrate layer is 10-50 μm;

[0034] The resin carbon layer comprises resin carbon, a conductive medium, and a hydrophobic layer, and the pore size of the resin carbon layer is 0.1-5 μm;

[0035] The microporous layer comprises a conductive medium, a hydrophobic layer, and carbon nanotubes, and the pore size of the microporous layer is 0.01-1 μm.

[0036] Thirdly, embodiments of the present invention provide an application of an electrode sheet with high strength, wherein the electrode sheet described in the second aspect is applied to the electrolytic synthesis of hydrogen peroxide or the electrolysis of water.

[0037] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows:

[0038] I. High Mechanical Strength. This invention constructs a "multi-layer carbon fiber substrate / resin carbon composite skeleton" as the core support, increasing the electrode sheet thickness to 500-2000μm. This significantly enhances the overall rigidity and compressive strength of the structure. The dense microporous layer coated on both sides not only optimizes the interface but also forms a mechanical interlock with the internal skeleton. This allows the structure to effectively resist deformation, delamination, or collapse under long-term immersion in electrolyte, gas pressure fluctuations, and assembly stress, ensuring the long-term integrity of the electrode structure and fundamentally avoiding the problem of unstable reaction interface caused by the mechanical decay of the electrode sheet.

[0039] II. Strong Water Resistance. The unique thick-layer design and multi-layered internal structure significantly extend the physical path for oxygen transport. Simultaneously, through resin carbonization and hydrophobic agent modification, a robust hydrophobic network is constructed on the carbon skeleton. The double-sided dense microporous layer acts as a selective barrier, allowing efficient gas passage while greatly increasing the capillary resistance to electrolyte permeation. This synergistic design of "long-path hydrophobic skeleton + double-sided dense barrier" ensures that the gas diffusion channel is not submerged in electrolyte during long-term operation, maintaining a stable gas-liquid-solid three-phase reaction interface, which is the cornerstone of achieving continuous and efficient electrolysis.

[0040] III. High Electrolysis Efficiency. The structure of this invention achieves integrated optimization of multiple transport properties: (1) The highly graphitized macroporous carbon paper skeleton provides excellent in-plane conductivity and extremely low electronic transport resistance; (2) The open macroporous structure ensures low-resistance diffusion of oxygen from the flow field to the catalyst layer; (3) The double-sided microporous layer finely controls the local distribution of gas at the catalyst interface. The combination of these three features reduces the mass transfer polarization and ohmic polarization of the reaction, thereby maintaining high Faraday efficiency and electrical energy utilization efficiency even at high current densities.

[0041] IV. Low Cost. Unlike traditional nickel or titanium mesh, this invention completely eliminates expensive metal substrates (such as titanium or nickel mesh) and precious metal coatings. It is based entirely on low-cost, widely available carbon materials (carbon fiber, resin carbon precursors, etc.), prepared through mature coating, carbonization, and graphitization processes. This technical route not only significantly reduces material costs but also possesses excellent feasibility for large-scale production and cost control potential, providing crucial material support for the commercial application of electrolytic hydrogen peroxide synthesis technology. Attached Figure Description

[0042] Figure 1 This is a flowchart of the electrode sheet preparation process in Embodiment 1 of the present invention.

[0043] Figure 2 This is a schematic diagram of the structure of the carbon paper layer in an embodiment of the present invention.

[0044] Figure 3 This is a schematic diagram of the electrode sheet structure in an embodiment of the present invention.

[0045] Figure 4 These are the carbon paper compression thickness curves in Embodiment 4 and Comparative Example 6 of the present invention.

[0046] Figure 5 These are the resistivity compression curves of the electrode sheets in Embodiment 4 and Comparative Example 6 of the present invention.

[0047] Figure labeling: 1a - base paper stacking; 1b - impregnation treatment; 1c - molten liquid treatment; 1d - drying and shaping; 1e - curing thickness limit; 1f - cooling and shaping; 1g - high temperature heat treatment; 1h - cutting; 1i - hydrophobic treatment; 1j - high temperature sintering; 1k - microporous layer coating; 1l - sintering treatment; 1m - sample completion;

[0048] 8-1-Base layer; 8-1-1-First base layer; 8-1-2-Second base layer; 8-1-n-1-n-1st base layer; 8-1-n-nth base layer; 8-2-Resin carbon layer; 8-2-1-First resin carbon layer; 8-2-2-Second resin carbon layer; 8-2-n-1-n-1st resin carbon layer; 8-Carbon paper layer; 11-Microporous layer; 11-1-First microporous layer; 11-2-Second microporous layer; 13-Electrode sheet. Detailed Implementation

[0049] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "inner" and "outer", "upper" and "lower", "left" and "right" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention.

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0051] Example 1

[0052] A method for preparing a high-strength electrode sheet includes the following steps:

[0053] Step S1: Cut to a weight of 30g / m 2 The carbon fiber paper measures 10×10cm and has a thickness of 300μm at 25kPa. Three sheets are stacked neatly and set aside. Figure 1 As shown in Figure 1a;

[0054] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 70:30 to form an impregnation solution, wherein the mass of phenolic resin is 70g and the mass of graphite powder is 30g. After stirring the phenolic resin solution for a period of time, pour it into a basin and turn on the ultrasonic treatment. Immerse the entire carbon fiber paper in the impregnation solution for 5 minutes. Figure 1 As shown in Figure 1b;

[0055] Step S3: Remove the impregnated carbon fiber paper as a whole and control the loading through the liquid rolling rollers, controlling the increment to be 150% of the total basis weight of the carbon fiber paper. Figure 1 As shown in 1c;

[0056] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying at 80℃ for 60 minutes to achieve overall surface dryness of the sample. Figure 1 As shown in 1d;

[0057] Step S5: After drying, place the sample in a flatbed hot press for curing. The curing temperature is 150℃, the pressure is set to 3MPa, and the holding time is 3 minutes. The final thickness of the cured paper is controlled at 500μm. Figure 1 As shown in 1e;

[0058] Step S6: After curing, remove and cool to set to obtain the carbon paper precursor, such as... Figure 1 As shown in 1f;

[0059] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, improving the sample's rigidity and conductivity. The carbonization temperature is set to 1000℃ for 60 minutes, and the graphitization temperature is set to 2400℃ for 60 minutes. Figure 1 As shown in 1g;

[0060] Step S8: After heat treatment, cool and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheets, such as... Figure 1 As shown in the middle 1h;

[0061] Step S9: Immerse the carbon paper in a polytetrafluoroethylene (PTFE) solution with a mass concentration of 10%, ensuring that the PTFE content in the carbon paper accounts for 15% of the carbon paper's basis weight. Then dry it. Figure 1 As shown in 1i;

[0062] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 5°C / min, hold for 30 minutes, then continue increasing the temperature to 400°C at a rate of 5°C / min, and sinter for another 30 minutes. This yields hydrophobic carbon paper with certain hydrophobic properties for use in electrolytic hydrogen peroxide electrode sheets. Figure 1 As shown in Figure 1j;

[0063] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 10:20:10:1:200, with 10g of XC-72R. After high-speed stirring and dispersion, a microporous slurry is formed. The microporous slurry is then coated onto the surface of hydrophobic carbon paper with a wet thickness of 90μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous slurry is coated onto the other side with a wet thickness of 90μm to form the second microporous layer. This is then dried. Figure 1 As shown in 1k;

[0064] Step S12: Place the dried assembly into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 5°C / min, hold for 30 minutes, then continue increasing the temperature to 400°C at a rate of 10°C / min, hold for 30 minutes, to obtain the electrode sheet. This electrode sheet will be used as the cathode material for the electrolytic synthesis of hydrogen peroxide. Figure 1 As shown in 1l and 1m.

[0065] like Figure 2 and 3 As shown, the electrode sheet consists of the following layers from top to bottom: first microporous layer 11-1, first substrate layer 8-1-1, first resin carbon layer 8-2-1, second substrate layer 8-1-2, second resin carbon layer 8-2-2, third substrate layer 8-1-3, and second microporous layer 11-2.

[0066] Example 2

[0067] A method for preparing a high-strength electrode sheet includes the following steps:

[0068] Step S1: Cut to a weight of 40g / m³ 2 The carbon fiber paper is 10×10cm in size and 550μm@25kPa in thickness. Six sheets are stacked neatly and set aside.

[0069] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 80:20 to form an impregnation solution, wherein the mass of phenolic resin is 80g. After stirring for a period of time, pour the mixture into a basin and turn on the ultrasonic treatment to immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0070] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 250% of the total basis weight of the carbon fiber paper;

[0071] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 90℃ and the time is 45 minutes to achieve overall surface dryness of the sample.

[0072] Step S5: After drying is complete, the sample is placed in a flatbed hot press for curing. The pressure is set to 4MPa, the temperature to 170℃, and the holding time to 6 minutes. The final thickness of the cured paper is controlled to be 1250μm.

[0073] Step S6: After curing, remove and cool to set to obtain the carbon paper precursor;

[0074] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1050℃ and the holding time is 45 minutes. The graphitization temperature is 2600℃ and the holding time is 45 minutes.

[0075] Step S8: After heat treatment, the material is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheets;

[0076] Step S9: Immerse the carbon paper in a PTFE solution with a mass concentration of 12.5%, and the PTFE in the carbon paper accounts for 22.5% of the carbon paper's basis weight. Then dry it.

[0077] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 5°C / min, hold for 45 minutes, and continue to increase the temperature to 375°C at a rate of 5°C / min, hold for 45 minutes, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheets with certain hydrophobic properties for later use.

[0078] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 12:24:12:1.2:250, with XC-72R weighing 12g. After high-speed stirring and dispersion, a microporous layer slurry is formed. The microporous layer slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 120μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous layer slurry is coated onto the other side with a wet thickness of 120μm to form the second microporous layer. After drying, the microporous layer is formed.

[0079] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 5°C / min and hold for 45 minutes. Continue to increase the temperature to 375°C at a rate of 5°C / min and hold for 45 minutes to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0080] like Figure 2 and 3As shown, the electrode sheet, from top to bottom, consists of: a first microporous layer 11-1, a first substrate layer 8-1-1, a first resin carbon layer 8-2-1, a second substrate layer 8-1-2, a second resin carbon layer 8-2-2, a third substrate layer 8-1-3, a third resin carbon layer 8-2-3, a fourth substrate layer 8-1-4, a fourth resin carbon layer 8-2-4, a fifth substrate layer 8-1-5, a fifth resin carbon layer 8-2-5, a sixth substrate layer 8-1-6, and a second microporous layer 11-2.

[0081] Example 3

[0082] A method for preparing a high-strength electrode sheet includes the following steps:

[0083] Step S1: Cut to a weight of 50g / m³ 2 The carbon fiber paper is 10×10cm in size and 800μm@25kPa in thickness. Ten sheets are stacked neatly and set aside.

[0084] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 90:10 to form an impregnation solution, wherein the mass of phenolic resin is 90g. After stirring for a period of time, pour the mixture into a basin and turn on the ultrasonic treatment to immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0085] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 300% of the total basis weight of the carbon fiber paper;

[0086] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 110℃ and the time is 30 minutes to achieve overall surface dryness of the sample.

[0087] Step S5: After drying is complete, the sample is placed in a flatbed hot press for curing. The pressure is set to 5MPa, the temperature to 150℃, and the holding time to 8 minutes. The final thickness of the cured paper is controlled to be 2000μm.

[0088] Step S6: After curing, remove and cool to set to obtain the carbon paper precursor;

[0089] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1100℃ and the holding time is 30 minutes. The graphitization temperature is 2800℃ and the holding time is 30 minutes.

[0090] Step S8: After heat treatment, the material is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheets;

[0091] Step S9: Immerse the carbon paper in a PTFE solution with a mass concentration of 15% and the PTFE content in the carbon paper is 30% of the carbon paper's basis weight, then dry it.

[0092] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 10°C / min, hold for 60 min, and continue to increase the temperature to 350°C at a rate of 10°C / min, hold for 60 min, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheets with certain hydrophobic properties for later use.

[0093] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 15:30:15:1.5:300, with 15g of XC-72R. After high-speed stirring and dispersion, a microporous slurry is formed. The microporous slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 150μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous slurry is coated onto the other side with a wet thickness of 150μm to form the second microporous layer. After drying, the second microporous layer is formed.

[0094] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 10°C / min and hold for 60 min. Continue to increase the temperature to 350°C at a rate of 10°C / min and hold for 60 min to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0095] like Figure 2 and 3 As shown, the electrode sheet, from top to bottom, consists of: a first microporous layer 11-1, a first substrate layer 8-1-1, a first resin carbon layer 8-2-1, a second substrate layer 8-1-2, a second resin carbon layer 8-2-2, a third substrate layer 8-1-3, a third resin carbon layer 8-2-3, a fourth substrate layer 8-1-4, a fourth resin carbon layer 8-2-4, a fifth substrate layer 8-1-5, a fifth resin carbon layer 8-2-5, a sixth substrate layer 8-1-6, a sixth resin carbon layer 8-2-6, a seventh substrate layer 8-1-7, a seventh resin carbon layer 8-2-7, an eighth substrate layer 8-1-8, an eighth resin carbon layer 8-2-8, a ninth substrate layer 8-1-9, a ninth resin carbon layer 8-2-9, a tenth substrate layer 8-1-10, and a second microporous layer 11-2.

[0096] Example 4

[0097] A method for preparing a high-strength electrode sheet includes the following steps:

[0098] Step S1: Cut to a weight of 50g / m³ 2The carbon fiber paper is 10×10cm in size and 500μm@25kPa in thickness. Four sheets are stacked neatly and set aside.

[0099] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 70:30 to form an impregnation solution. The mass of phenolic resin is 70g and the mass of graphite powder is 30g. After stirring the phenolic resin for a period of time, pour it into a basin and turn on the ultrasonic treatment. Immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0100] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 150% of the total basis weight of the carbon fiber paper;

[0101] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 80℃ and the time is 60 minutes to achieve overall surface dryness of the sample.

[0102] Step S5: After drying is complete, the sample is placed in a flatbed hot press for curing. The curing temperature is 150℃, the pressure is set to 3MPa, the holding time is 3 minutes, and the final thickness of the cured paper is controlled to be 900μm.

[0103] Step S6: After curing, remove and cool to set to obtain the carbon paper precursor;

[0104] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1000℃ and the holding time is 60 minutes. The graphitization temperature is 2400℃ and the holding time is 60 minutes.

[0105] Step S8: After heat treatment, the material is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheets;

[0106] Step S9: Immerse the carbon paper in a polytetrafluoroethylene (PTFE) solution with a mass concentration of 10% and the PTFE content in the carbon paper is 15% of the carbon paper's basis weight. Then dry it.

[0107] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 10°C / min, hold for 60 min, and continue to increase the temperature to 400°C at a rate of 10°C / min, hold for 30 min, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheet with certain hydrophobic properties for later use.

[0108] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 10:20:10:1:200, with 10g of XC-72R. After high-speed stirring and dispersion, a microporous layer slurry is formed. The microporous layer slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 90μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous layer slurry is coated onto the other side with a wet thickness of 90μm to form the second microporous layer. After drying, the second microporous layer is formed.

[0109] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 10°C / min and hold for 60 min. Continue to increase the temperature to 400°C at a rate of 10°C / min and hold for 30 min to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0110] like Figure 2 and 3 As shown, the electrode sheet consists of the following layers from top to bottom: first microporous layer 11-1, first substrate layer 8-1-1, first resin carbon layer 8-2-1, second substrate layer 8-1-2, second resin carbon layer 8-2-2, third substrate layer 8-1-3, third resin carbon layer 8-2-3, fourth substrate layer 8-1-4, and second microporous layer 11-2.

[0111] Comparative Example 1

[0112] A method for preparing an electrode sheet includes the following steps:

[0113] Step S1: Cut to a weight of 30g / m 2 The carbon fiber paper has a size of 10×10cm and a thickness of 300μm@25kPa, and is available for later use;

[0114] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 70:30 to form an impregnation solution, wherein the mass of phenolic resin is 70g. After stirring for a period of time, pour the mixture into a basin and turn on the ultrasonic treatment to immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0115] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 150% of the total basis weight of the carbon fiber paper;

[0116] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 80℃ and the time is 60 minutes to achieve overall surface dryness of the sample.

[0117] Step S5: After drying is complete, place the sample into a flatbed hot press for curing. Stack the three sheets together, set the curing temperature to 150°C, the pressure to 3MPa, and the holding time to 3 minutes. The final thickness of the cured paper is controlled to be 500μm.

[0118] Step S6: After curing, remove and cool to set to obtain the carbon paper precursor;

[0119] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1000℃ and the holding time is 60 minutes. The graphitization temperature is 2400℃ and the holding time is 60 minutes.

[0120] Step S8: After heat treatment, the paper is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheet.

[0121] Step S9: Immerse the carbon paper in a PTFE solution with a mass concentration of 10% and the PTFE content in the carbon paper accounts for 15% of the carbon paper's basis weight. Then dry it.

[0122] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 10°C / min, hold for 60 min, and continue to increase the temperature to 400°C at a rate of 10°C / min, hold for 30 min, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheet with certain hydrophobic properties for later use.

[0123] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 10:20:10:1:200, with 10g of XC-72R. After high-speed stirring and dispersion, a microporous layer slurry is formed. The microporous layer slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 90μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous layer slurry is coated onto the other side with a wet thickness of 90μm to form the second microporous layer. After drying, the second microporous layer is formed.

[0124] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 10°C / min and hold for 60 min. Continue to increase the temperature to 400°C at a rate of 10°C / min and hold for 30 min to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0125] Comparative Example 2

[0126] A method for preparing an electrode sheet includes the following steps:

[0127] Step S1: Cut to a weight of 20g / m³ 2 The carbon fiber paper is 10×10cm in size and 200μm@25kPa in thickness. After stacking 3 sheets neatly, it is ready for use.

[0128] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 70:30 to form an impregnation solution, wherein the mass of phenolic resin is 70g. After stirring for a period of time, pour the mixture into a basin and turn on the ultrasonic treatment to immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0129] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 150% of the total basis weight of the carbon fiber paper;

[0130] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 80℃ and the time is 60 minutes to achieve overall surface dryness of the sample.

[0131] Step S5: After drying is complete, the sample is placed in a flatbed hot press for curing. The curing temperature is 150℃, the pressure is set to 3MPa, the holding time is 3 minutes, and the final thickness of the cured paper is controlled to be 400μm.

[0132] Step S6: After curing, remove and cool to set to obtain the carbon paper precursor;

[0133] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1000℃ and the holding time is 60 minutes. The graphitization temperature is 2400℃ and the holding time is 60 minutes.

[0134] Step S8: After heat treatment, the material is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheets;

[0135] Step S9: Immerse the carbon paper in a PTFE solution with a mass concentration of 10% and the PTFE content in the carbon paper accounts for 15% of the carbon paper's basis weight, and then dry it.

[0136] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 5°C / min, hold for 30 min, and continue to increase the temperature to 400°C at a rate of 5°C / min, hold for 30 min, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheets with certain hydrophobic properties for later use.

[0137] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 10:20:10:1:200, with 10g of XC-72R. After high-speed stirring and dispersion, a microporous layer slurry is formed. The microporous layer slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 90μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous layer slurry is coated onto the other side with a wet thickness of 90μm to form the second microporous layer. After drying, the second microporous layer is formed.

[0138] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 5°C / min and hold for 30 minutes. Continue to increase the temperature to 400°C at a rate of 5°C / min and hold for 30 minutes to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0139] Comparative Example 3

[0140] A method for preparing an electrode sheet includes the following steps:

[0141] Step S1: Cut to a weight of 30g / m 2 The carbon fiber paper is 10 cm × 10 cm in size and 300 μm @ 25 kPa in thickness. After stacking two sheets neatly, they are ready for use.

[0142] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 70:30 to form an impregnation solution, wherein the mass of phenolic resin is 70g. After stirring for a period of time, pour the mixture into a basin and turn on the ultrasonic treatment to immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0143] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 150% of the total basis weight of the carbon fiber paper;

[0144] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 80℃ and the time is 60 minutes to achieve overall surface dryness of the sample.

[0145] Step S5: After drying is complete, the sample is placed in a flatbed hot press for curing. The curing temperature is 150℃, the pressure is set to 3MPa, the holding time is 3 minutes, and the final thickness of the cured paper is controlled to be 400μm.

[0146] Step S6: After curing, remove and cool to set to obtain the carbon paper precursor;

[0147] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1000℃ and the holding time is 60 minutes. The graphitization temperature is 2400℃ and the holding time is 60 minutes.

[0148] Step S8: After heat treatment, the material is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheets;

[0149] Step S9: Immerse the carbon paper in a PTFE solution with a mass concentration of 10% and the PTFE content in the carbon paper accounts for 15% of the carbon paper's basis weight, and then dry it.

[0150] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 5°C / min, hold for 30 min, and continue to increase the temperature to 400°C at a rate of 5°C / min, hold for 30 min, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheets with certain hydrophobic properties for later use.

[0151] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 10:20:10:1:200, with 10g of XC-72R. After high-speed stirring and dispersion, a microporous layer slurry is formed. The microporous layer slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 90μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous layer slurry is coated onto the other side with a wet thickness of 90μm to form the second microporous layer. After drying, the second microporous layer is formed.

[0152] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 5°C / min and hold for 30 minutes. Continue to increase the temperature to 400°C at a rate of 5°C / min and hold for 30 minutes to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0153] Comparative Example 4

[0154] A method for preparing an electrode sheet includes the following steps:

[0155] Step S1: Cut to a weight of 30g / m 2 The carbon fiber paper is 10×10cm in size and 300μm@25kPa in thickness. Eleven sheets are stacked neatly and set aside.

[0156] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 70:30 to form an impregnation solution, wherein the mass of phenolic resin is 70g. After stirring for a period of time, pour the mixture into a basin and turn on the ultrasonic treatment to immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0157] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 150% of the total basis weight of the carbon fiber paper;

[0158] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 80℃ and the time is 60 minutes to achieve overall surface dryness of the sample.

[0159] Step S5: After drying is complete, the sample is placed in a flatbed hot press for curing. The curing temperature is 150℃, the pressure is set to 3MPa, the pressure holding time is 3 minutes, and the final thickness of the cured paper is controlled to be 2500μm.

[0160] Step S6: After curing, cool and set to obtain the carbon paper precursor.

[0161] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1000℃ and the holding time is 60 minutes. The graphitization temperature is 2400℃ and the holding time is 60 minutes.

[0162] Step S8: After heat treatment, the material is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheets;

[0163] Step S9: Immerse the carbon paper in a PTFE solution with a mass concentration of 10% and the PTFE content in the carbon paper accounts for 15% of the carbon paper's basis weight. Then dry it.

[0164] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 5°C / min, hold for 30 min, and continue to increase the temperature to 400°C at a rate of 5°C / min, hold for 30 min, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheets with certain hydrophobic properties for later use.

[0165] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 10:20:10:1:200, with 10g of XC-72R. After high-speed stirring and dispersion, a microporous layer slurry is formed. The microporous layer slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 90μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous layer slurry is coated onto the other side with a wet thickness of 90μm to form the second microporous layer. After drying, the second microporous layer is formed.

[0166] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 5°C / min and hold for 30 minutes. Continue to increase the temperature to 400°C at a rate of 5°C / min and hold for 30 minutes to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0167] Comparative Example 5

[0168] A method for preparing an electrode sheet includes the following steps:

[0169] Step S1: Cut to a weight of 30g / m 2 The carbon fiber paper is 10×10cm in size and 300μm@25kPa in thickness. Three sheets are stacked neatly and set aside.

[0170] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 50:50 to form an impregnation solution, wherein the mass of phenolic resin is 50g. After stirring for a period of time, pour the mixture into a basin and turn on the ultrasonic treatment to immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0171] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 150% of the total basis weight of the carbon fiber paper;

[0172] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 80℃ and the time is 60 minutes to achieve overall surface dryness of the sample.

[0173] Step S5: After drying is complete, the sample is placed in a flatbed hot press for curing. The curing temperature is 150℃, the pressure is set to 3MPa, the holding time is 3 minutes, and the final thickness of the cured paper is controlled to be 500μm.

[0174] Step S6: After curing, remove and cool to set to obtain the carbon paper precursor;

[0175] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1000℃ and the holding time is 60 minutes. The graphitization temperature is 2400℃ and the holding time is 60 minutes.

[0176] Step S8: After heat treatment, the paper is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheet.

[0177] Step S9: Immerse the carbon paper in a PTFE solution with a mass concentration of 10% and the PTFE content in the carbon paper accounts for 15% of the carbon paper's basis weight. Then dry it.

[0178] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 5°C / min, hold for 30 min, and continue to increase the temperature to 400°C at a rate of 5°C / min, hold for 30 min, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheet with certain hydrophobic properties for later use.

[0179] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 10:20:10:1:200, with 10g of XC-72R. After high-speed stirring and dispersion, a microporous layer slurry is formed. The microporous layer slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 90μm. After drying, the first microporous layer is formed. Then, the carbon paper is flipped over, and the microporous layer slurry is coated onto the other side with a wet thickness of 90μm to form the second microporous layer. After drying, the second microporous layer is formed.

[0180] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 5°C / min and hold for 30 minutes. Continue to increase the temperature to 400°C at a rate of 5°C / min and hold for 30 minutes to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0181] Comparative Example 6

[0182] This comparative example mainly uses Toray 055 commercial diffusion layer, with four sheets stacked together.

[0183] Comparative Example 7

[0184] A method for preparing an electrode sheet includes the following steps:

[0185] Step S1: Cut to a weight of 30g / m 2 The carbon fiber paper is 10×10cm in size and 300μm@25kPa in thickness. Three sheets are stacked neatly and set aside.

[0186] Step S2: Mix phenolic resin solution and graphite powder at a mass ratio of 70:30 to form an impregnation solution, wherein the mass of phenolic resin is 70g. After stirring for a period of time, pour the mixture into a basin and turn on the ultrasonic treatment to immerse the carbon fiber paper in the impregnation solution for 5 minutes.

[0187] Step S3: Remove the impregnated carbon fiber paper as a whole and control the load through the liquid rolling roller, controlling the increment to be 150% of the total basis weight of the carbon fiber paper;

[0188] Step S4: After the liquid rolling is completed, the carbon fiber paper is placed in an oven for drying. The oven temperature is 80℃ and the time is 60 minutes to achieve overall surface dryness of the sample.

[0189] Step S5: After drying is complete, the sample is placed in a flatbed hot press for curing. The curing temperature is 150℃, the pressure is set to 3MPa, the holding time is 3 minutes, and the final thickness of the cured paper is controlled to be 500μm.

[0190] Step S6: After curing, cool and set to obtain the carbon paper precursor.

[0191] Step S7: Transfer the carbon paper precursor to a high-temperature carbonization and graphitization furnace for high-temperature treatment to form a resin carbon structure inside the sample, thereby improving the rigidity and conductivity of the sample. The carbonization temperature is set to 1000℃ and the holding time is 60 minutes. The graphitization temperature is 2400℃ and the holding time is 60 minutes.

[0192] Step S8: After heat treatment, the material is cooled and cut to form carbon paper for electrolytic hydrogen peroxide electrode sheets;

[0193] Step S9: Immerse the carbon paper in a PTFE solution with a mass concentration of 10% and the PTFE content in the carbon paper accounts for 15% of the carbon paper's basis weight, and then dry it.

[0194] Step S10: Place the PTFE-impregnated carbon paper into a high-temperature furnace for high-temperature sintering. Increase the temperature from room temperature to 240°C at a rate of 5°C / min, hold for 30 min, and continue to increase the temperature to 400°C at a rate of 5°C / min, hold for 30 min, and obtain hydrophobic carbon paper for electrolytic synthesis of hydrogen peroxide electrode sheets with certain hydrophobic properties for later use.

[0195] Step S11: Mix XC-72R, PTFE, carbon nanotubes, surfactant, and deionized water uniformly in a mass ratio of 10:20:10:1:200, with XC-72R weighing 10g. After high-speed stirring and dispersion, a microporous layer slurry is formed. The microporous layer slurry is coated onto the surface of hydrophobic carbon paper with a wet thickness of 90μm. After drying, the first microporous layer is formed.

[0196] Step S12: Place the dried whole into an oven for high-temperature heat treatment. Increase the temperature from room temperature to 240°C at a rate of 5°C / min and hold for 30 minutes. Continue to increase the temperature to 400°C at a rate of 5°C / min and hold for 30 minutes to obtain an electrode sheet, which is used as a cathode material for electrolytic synthesis of hydrogen peroxide.

[0197] The raw materials used in the examples and comparative examples are as follows: The phenolic resin used is thermosetting phenolic resin, model 2130. The polytetrafluoroethylene (PTFE) raw material used is DuPont DISP30, with a solids content of 60%, which was diluted as needed in the examples and comparative examples. The surfactant used is Tween 80. The parameters of the graphite powder are as follows: D 50 2-4μm; D 90 ≤6μm; specific surface area (WFEC): 9~14m² / g. The parameters of carbon nanotubes are as follows: diameter 150nm, length 6μm, specific surface area 13m² / g. 2 / g.

[0198] The electrode sheets in Examples 1-4 and Comparative Examples 1-7 were coated with a loading of 0.5 mg / cm³. 2 A carbon-based catalyst (Cabot BP2000) forms the cathode, while the anode material remains unchanged, both being carbon-based catalysts (Cabot BP2000) with a loading of 0.5 mg / cm³. 2 The titanium plate material has a total electrolytic activation area of ​​25 cm². 2 Electrolysis conditions: Cross-current conditions, current density 20 mA / cm² 2 The current was 0.5A, the water flow rate was 100mL / min, and the anode materials and reaction conditions were kept the same in all examples and comparative examples, except that the cathode materials were changed.

[0199] Table 1 Summary of performance parameters of electrode sheets in Examples 1-4 and Comparative Examples 1-7

[0200]

[0201] As shown in Table 1, the electrode sheet prepared by this invention meets the strength requirements for cathode electrodes used in hydrogen peroxide electrolysis under controllable thickness conditions. Furthermore, through the combination of multiple substrate layers and resin carbon layers, it exhibits high overall integrity and mechanical strength, maintaining high structural integrity even under prolonged strong oxidizing electrolysis environments. In Examples 1-3, the final thickness increases from 450 μm to 1800 μm with increasing layer count, while the resistivity increases with increasing electrode sheet thickness. In Example 3, when n=10 layers, the resistivity reaches 18 mΩ·cm. 2The corresponding hydrogen peroxide concentration at the outlet decreased from 1500 ppm in Example 1 to 830 ppm. In Comparative Example 4, as the number of layers increased to 11, the resin carbon filled in the system and the large pores of the substrate blocked gas transmission, making it relatively dense. In the actual electrolysis process, the oxygen diffusion capacity of the cathode was greatly reduced, resulting in an outlet concentration of only 300 ppm. Similarly, in Comparative Example 5, due to the close ratio of resin to conductive medium, the amount of resin carbon formed after graphitization was insufficient, resulting in insufficient strength of the carbon paper during use. Water seepage occurred during long-term electrolysis. Moreover, due to the excessive amount of conductive medium added (50%), there were more small pores and fewer large pores inside the resin carbon layer and the substrate layer. The oxygen diffusion capacity of the cathode was limited during electrolysis, and the outlet hydrogen peroxide concentration was only 576 ppm.

[0202] The electrode sheet for the cathode of hydrogen peroxide electrolysis requires attention to structural integrity. The stacking of multiple layers ensures a tight bond between the macropores and micropores of the substrate. This invention utilizes the bonding effect of resin during impregnation, filling a certain amount of resin inside the carbon fiber paper and between the two layers, thus initially forming a unified structure. After hot pressing, curing, and graphitization, the two structures become inseparable. In contrast, in Comparative Example 1, a single layer was pre-impregnated with resin, dried, and then hot-pressed together. Although a unified structure was formed during curing, the internal structure collapsed and delamination occurred during prolonged electrolysis. Similarly, stacking multiple sheets of GDL to meet the strength requirements for hydrogen peroxide electrolysis, as in Comparative Example 6, where a single sheet of Toray 055 is 160 μm thick, and four sheets stacked together have a total thickness of 600 μm, seemingly meeting the thickness requirements for the carbon paper of the hydrogen peroxide cathode, results in a lack of interlayer bonding and a high interfacial resistance, with an overall resistivity reaching 21 mΩ·cm. 2 Due to the large ohmic loss, its effective electrolysis efficiency is low, and the hydrogen peroxide concentration at the outlet is only 300ppm. Moreover, there is an interface inside, and after a long period of electrolysis operation, water seepage occurs on the outside, that is, the hydrophobic properties of the body are damaged.

[0203] In the electrolytic synthesis of hydrogen peroxide, hydroxyl groups are continuously generated at the cathode. The formation of hydroxyl groups causes some damage to the material itself, gradually diminishing its hydrophobic properties. In Comparative Example 7, only a microporous layer was coated. This microporous layer has a dense microporous structure, which is effective in inhibiting water leakage. However, the carbon paper has large pores inside, which effectively diffuse oxygen. Although it has high strength, air permeability, and low resistivity, and the initial electrolytic concentration is high, after long-term operation, water seepage appeared on the side without the microporous layer. Water blocked the large pores and internal pore channels, resulting in poor oxygen diffusion. Ultimately, the hydrogen peroxide concentration decreased from 1500 ppm to 200 ppm.

[0204] like Figure 4 As shown, the electrode sheet for electrolytic synthesis of hydrogen peroxide prepared in Example 4, after compression at 0-1.5 MPa, had its thickness reduced from 824 μm@50 kPa to 703 μm@1.5 MPa, a thickness compression rate of 14.7%@1.5 MPa. In contrast, the thickness of the four sheets of Toray 055 in Comparative Example 6, after being stacked, was reduced from 671 μm@50 kPa to 498 μm@1.5 MPa, a thickness compression rate of 25.8%@1.5 MPa. This thickness compression rate is twice that of the present invention, indicating that the electrode sheet prepared by the present invention has a strong rigid structure. Furthermore, after compression at 1.5 MPa, the thickness of the electrode sheet of the present invention returned to 804 μm@50 kPa, with a permanent mechanical thickness compression of 2.4%. In contrast, the thickness of the four sheets of Toray 055, after compression at 1.5 MPa, was only 586 μm@50 kPa, with a permanent mechanical thickness compression of 12.7%. This demonstrates that the mechanical properties of the electrode sheet prepared by the present invention far exceed commercial performance.

[0205] like Figure 5 As shown, although the electrode sheet prepared in this invention contains excessive amounts of PTFE and other polymer materials to improve rigidity, and this material is non-conductive, it can strongly provide hydrophobic properties. Data shows that the four stacked Toray 055 commercial diffusion layers, although relatively thin, have a high bulk resistivity, with a resistivity of 31.35 mΩ·cm at 1 MPa. 2 The electrode sheet prepared by this invention has a bulk resistance of only 26.7 mΩ·cm. 2 With a pressure of 1 MPa, this invention achieves higher thickness, higher mechanical strength, and higher hydrophobicity, while also exhibiting lower bulk resistance and further improved electrolysis efficiency.

[0206] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a high-strength electrode sheet, characterized in that, Includes the following steps: Step S1, Stacking of base paper: Cut multiple sheets of high-grammage carbon fiber paper and stack them neatly; Step S2, Impregnation treatment: The multiple sheets of carbon fiber paper stacked neatly in step S1 are immersed in the impregnation solution for impregnation. Step S3, Pulping Treatment: Multiple sheets of carbon fiber paper impregnated with resin solution are placed into pulping rollers for rolling, and the weight gain is controlled to be 150-300% of the total basis weight of the carbon fiber paper; Step S4, Drying and Shaping: The carbon fiber paper after liquid injection is dried at a temperature of 80-110℃ for 30-60 minutes to achieve surface dryness. Step S5, Curing and Thickness Limiting: Place the carbon fiber paper dried in step S4 into a flatbed hot press for curing. Step S6, Cooling and Shaping: After curing is complete, remove the cooled and shaped material to obtain the carbon paper precursor; Step S7, High-temperature heat treatment: The carbon paper precursor obtained in step S6 is placed in a carbonization and graphitization furnace for high-temperature heat treatment. The carbonization temperature is 1000-1100℃ and the holding time is 30-60 minutes; the graphitization temperature is 2400-2800℃ and the holding time is 30-60 minutes. Step S8, Cutting: After heat treatment, the paper is cooled and cut to form carbon paper; Step S9, Hydrophobic treatment: The carbon paper described in step S8 is placed in a polytetrafluoroethylene solution for hydrophobic treatment, and then dried. Step S10, High-temperature sintering: Place the carbon paper impregnated with polytetrafluoroethylene into a high-temperature furnace for programmed heating. Increase the temperature from room temperature to 240°C at a rate of 5-10°C / min, hold for 30-60 min, and continue heating at a rate of 5-10°C / min to 350-400°C. Sinter at high temperature for 30-60 min. Step S11, microporous layer coating: The microporous layer slurry is uniformly coated onto one side of the hydrophobic carbon paper, and then dried to form the first microporous layer (11-1). After drying, the microporous layer slurry is coated on the other side to form the second microporous layer (11-2), thus forming a dense microporous layer on both sides of the carbon paper. Step S12, Sintering treatment: Place the coated sample into a high-temperature furnace for programmed heating, raising the temperature from room temperature to 240°C at a rate of 5-10°C / min, holding for 30-60 min, and continuing to raise the temperature to 350-400°C at a rate of 5-10°C / min, and sintering at high temperature for 30-60 min. Step S13, Sample Completion: After cooling, the electrode sheet is obtained; In step S1, the number of sheets of carbon fiber paper is 3-10; In step S2, the impregnation solution includes phenolic resin and a conductive medium, wherein the mass ratio of the phenolic resin to the conductive medium is 70-90:30-10, and the conductive medium is one or more combinations of graphite powder, graphene, and acetylene black. In step S11, the microporous layer slurry is composed of a conductive medium, polytetrafluoroethylene, carbon nanotubes, surfactants, and deionized water.

2. The method for preparing a high-strength electrode sheet according to claim 1, characterized in that, In step S1, the basis weight of the carbon fiber paper is 30-50 g / m³. 2 Thickness is 300-800μm@25KPa.

3. The method for preparing a high-strength electrode sheet according to claim 1, characterized in that, In step S5, the pressure of the flatbed hot press is set to 3-5 MPa, the temperature to 150-180℃, the holding time to 3-8 minutes, and the final thickness of the cured paper is controlled to be 500-2000 μm.

4. The method for preparing a high-strength electrode sheet according to claim 1, characterized in that, In step S9, the mass concentration of the polytetrafluoroethylene solution is 10-15%, and the mass fraction of polytetrafluoroethylene in the carbon paper is 15-30% of the carbon paper basis weight.

5. The method for preparing a high-strength electrode sheet according to claim 1, characterized in that, In step S11, the mass ratio of conductive medium, polytetrafluoroethylene, carbon nanotubes, surfactant and deionized material in the microporous layer slurry is 10-15:20-30:10-15:1-1.5:200-300. The conductive medium is one or more of XC-72R, acetylene black, graphene, and graphite powder. The wet thickness of the first microporous layer (11-1) and the second microporous layer (11-2) is 90-150 μm.

6. An electrode sheet with high strength, characterized in that, The electrode sheet (13) is prepared by any one of the preparation methods described in claims 1-5, and comprises n-layer substrate layer (8-1), n-1-layer resin carbon layer (8-2), and two microporous layers (11). The electrode sheet, from top to bottom, consists of: a first microporous layer (11-1), a first substrate layer (8-1-1), a first resin carbon layer (8-2-1), a second substrate layer (8-1-2), a second resin carbon layer (8-2-2), ..., an (n-1)th substrate layer (8-1-n-1), an (n-1)th resin carbon layer (8-2-n-1), an nth substrate layer (8-1-n), and a second microporous layer (11-2), where n is between 3 and 10.

7. The high-strength electrode sheet according to claim 6, characterized in that, The overall thickness of the electrode sheet (13) is 450-2000 μm.

8. The high-strength electrode sheet according to claim 6, characterized in that, The substrate layer (8-1) includes conductive carbon fibers, resin carbon, conductive dielectric and hydrophobic layer, and the pore size of the substrate layer (8-1) is 10-50 μm; The resin carbon layer (8-2) comprises resin carbon, a conductive medium, and a hydrophobic layer, and the pore size of the resin carbon layer (8-2) is 0.1-5 μm; The microporous layer (11) includes a conductive medium, a hydrophobic layer and carbon nanotubes, and the pore size of the microporous layer (11) is 0.01-1μm.

9. An application of a high-strength electrode sheet, characterized in that, The electrode sheet according to any one of claims 6-8 is used in the electrolytic synthesis of hydrogen peroxide or the electrolysis of water.

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