A hydrophilic-hydrophobic alternating stripe electrode and a method for preparing the same

Abstract

The application discloses a kind of hydrophilic and hydrophobic alternating stripe electrode and preparation method thereof, belong to electrochemical energy conversion device technical field;The method mixes hydrophilic substance precursor, hydrophobic substance precursor and soluble transition metal salt, adds solvent and dispersing agent, forms uniform composite slurry;The composite slurry is coated on the surface of conductive substrate, then pre-drying is carried out, to obtain the electrode covered with solid composite precursor film;Using femtosecond laser system, the electrode covered with solid composite precursor film is arrayed focused scanning, scanning forms stripe region, completes laser selective striping treatment;The electrode after laser selective striping treatment is immersed in water, and a hydrophilic and hydrophobic alternating stripe electrode is obtained.The application creates "functional stripe" on the electrode surface through ultrafast laser processing technology, realizes the spatial decoupling and cooperation of reaction zone and desorption zone.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy conversion device technology, and relates to a hydrophilic and aerophilic alternating stripe electrode and its preparation method. Background Technology

[0002] Electrolysis of water to produce hydrogen, as a core technology for green hydrogen production, is rapidly upgrading towards industrialization with high current density, low energy consumption, and long lifespan. Electrodes, as the core components of the electrolyzer, directly determine the system's energy efficiency and economy through their surface reactions and mass transfer efficiency. However, bubble management under high current density conditions is currently a key bottleneck restricting technological breakthroughs.

[0003] Existing water electrolysis electrodes generally employ a homogeneous catalytic layer design, requiring the simultaneous fulfillment of two conflicting functional requirements on a single surface: efficient catalysis and rapid bubble desorption. On one hand, the catalytic reaction demands good hydrophilicity to ensure sufficient wetting and transport of water molecules and electrolyte ions, thereby improving the utilization rate of active sites. On the other hand, bubble desorption requires the surface to possess certain hydrophobic or gas-philic properties to reduce bubble adhesion energy and prevent bubble retention that covers active sites. This functional coupling contradiction forces traditional electrodes to operate only within a compromise between hydrophilicity and hydrophobicity: excessive hydrophilicity makes bubble detachment difficult, causing bubble accumulation on the surface, physically shielding active sites, increasing ohmic impedance, and mass transfer polarization; excessive hydrophobicity hinders reactant supply, reducing catalytic reaction efficiency. Even with attempts to optimize these technologies through surface coating modification and microstructure design, the fundamental problem of the mutual incompatibility between these two performance characteristics remains unresolved. The issues of increased electrode overpotential, increased energy consumption, and decreased stability at high current densities (≥500 mA / cm²) persist.

[0004] Meanwhile, existing electrode fabrication processes mostly employ traditional methods such as physical coating and thermal sintering, resulting in weak adhesion between the catalytic layer and the substrate. During long-term operation, these layers are susceptible to erosion by air bubbles, leading to coating peeling and activity degradation. Conventional etching and template methods struggle to achieve nanoscale functional partitioning, failing to simultaneously meet the dual requirements of precise catalytic site construction and controllable bubble channel design. Therefore, a novel electrode structure design approach and fabrication process are urgently needed to decouple catalysis and desorption functions spatially, breaking through the performance limitations of traditional homogeneous electrodes while considering the scalability and cost requirements of industrial production. This would provide core support for the large-scale application of water electrolysis for hydrogen production. Summary of the Invention

[0005] The purpose of this invention is to provide a hydrophilic and aerophilic alternating stripe electrode and its preparation method, so as to solve the technical problem that existing electrodes are difficult to simultaneously meet the requirements of high hydrophilicity catalysis and high hydrophobicity bubble desorption.

[0006] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a method for preparing a hydrophilic-aerophilic alternating stripe electrode, comprising the following steps: A hydrophilic precursor, a gas-philic precursor, and a soluble transition metal salt are mixed, and a solvent and dispersant are added to form a uniform composite slurry. The composite slurry is coated on the surface of a conductive substrate and then pre-dried to obtain an electrode coated with a solid composite precursor film. A femtosecond laser system is used to perform array-type focused scanning on the electrode covered with a solid composite precursor film, and the scanning forms a striped region to complete the laser selective striping process. Electrodes treated with laser selective striping are subjected to water immersion to obtain hydrophilic and aerophilic alternating stripe electrodes.

[0007] Further, the hydrophilic precursor includes one or more mixtures of silica sol, tetrabutyl titanate, alumina sol, and zirconate ester, and the solid content of the hydrophilic precursor in the composite slurry is 5% to 40%; the aerophilic precursor includes one or more mixtures of fluorinated silane, perfluorosulfonic acid resin, polytetrafluoroethylene emulsion, and fluorinated acrylate, and the solid content of the aerophilic precursor in the composite slurry is 2% to 30%; the soluble transition metal salt is one or more of nitrate, chloride, acetate, and acetylacetonate, and the metal element in the soluble transition metal salt includes one or more of nickel, cobalt, iron, molybdenum, tungsten, iridium, and ruthenium, and the total concentration of the soluble transition metal salt in the composite slurry, calculated as metal ions, is 0.01 to 2.0 mol / L.

[0008] Further, the solvent is one or more of deionized water, ethanol, isopropanol, N-methylpyrrolidone, and N,N-dimethylformamide; the dispersant is one or more of polyvinylpyrrolidone, polyethylene glycol, and sodium dodecylbenzenesulfonate, and the amount of dispersant added is 0.1% to 5% of the total mass of the slurry; the dry matter mass ratio of the hydrophilic precursor to the aerophilic precursor is (1 to 5):(1 to 5); and the viscosity of the composite slurry is 10 mPa·s to 5000 mPa·s.

[0009] Furthermore, the conductive substrate is nickel foam, nickel felt, titanium foam, titanium mesh, carbon cloth, or carbon paper, and the thickness of the conductive substrate is 0.1 mm to 5 mm, with a porosity of 50% to 98%; the coating method includes scraping, spin coating, dip coating, spraying, or screen printing, and the coating thickness is 5 μm to 200 μm.

[0010] Furthermore, the pre-drying temperature is 40℃~120℃, the drying time is 10 minutes~12 hours, and the drying atmosphere is air or an inert atmosphere; the dry film thickness of the pre-dried solid composite precursor film is 1μm~50μm.

[0011] Furthermore, the parameters of the femtosecond laser system are set as follows: the center wavelength of the femtosecond laser is 1030 nm, 515 nm, or 343 nm; the pulse width is 10~500 fs; the laser single pulse energy is 0.1 μJ~100 μJ; the repetition frequency is 1 kHz~1 MHz; the laser focusing spot diameter is 1 μm~20 μm; the scanning line spacing is 50 μm~500 μm; the laser scanning speed is 1 mm / s~10 mm / s; the scanning path is a parallel straight line; the instantaneous high-temperature micro-area temperature generated during laser scanning is >3000 K; and the high-temperature duration is 10... -9 s ~ 10 -6 s.

[0012] Furthermore, the medium used for the water immersion treatment is deionized water, ultrapure water, or a weakly acidic / weakly alkaline aqueous solution, with a water temperature of 20℃ to 90℃; the water immersion treatment time is 0.5 hours to 24 hours.

[0013] Furthermore, the water immersion process is supplemented by ultrasonic oscillation or mechanical stirring, wherein the ultrasonic power of the ultrasonic oscillation is 50W~500W and the frequency is 20kHz~40kHz.

[0014] Furthermore, after the step of immersing the electrode after laser selective striping treatment in water, the method further includes rinsing the electrode with deionized water to remove residual soluble substances, and then drying it at 40℃~120℃ for 0.5 hours to 5 hours; finally obtaining a hydrophilic and aerophilic alternating striped electrode.

[0015] Secondly, the present invention provides a hydrophilic-aerophilic alternating stripe electrode, which is prepared by the above-mentioned method for preparing a hydrophilic-aerophilic alternating stripe electrode. The surface of the hydrophilic-aerophilic alternating stripe electrode has alternating hydrophilic catalytic stripes and aerophilic stripes; the width of both the hydrophilic catalytic stripes and the aerophilic stripes is 25 μm to 250 μm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for fabricating a hydrophilic and aerophilic alternating stripe electrode. Through an in-situ process of "precise laser synthesis + selective chemical removal," a highly integrated and stable interface is constructed, ensuring the electrode's durability and reliability. The fabrication process of this invention possesses high controllability and inventiveness. First, the ultrafast and ultra-intense thermal effect of femtosecond lasers can not only precisely etch patterns at the micrometer scale, but more importantly, it can instantaneously (10⁻⁶)... -9 ~ 10 -6s) The pyrolysis and transformation of the precursor are completed, generating a catalytically active phase in situ within the striped region and firmly "welding" it to the substrate, avoiding the interfacial resistance and detachment risk caused by physical coating of the catalytic layer. Subsequently, a gentle water immersion treatment cleverly utilizes the difference in chemical stability between the laser-treated and untreated regions to achieve selective functionalization: only non-target components are dissolved and eluted, while a chemically bonded aerophilic coating is constructed in situ in the interstitial region through hydrolysis. The entire process ensures that both the hydrophilic catalytic phase and the aerophilic phase are chemically and firmly bonded to the substrate, forming an integrated composite structure of "electrode substrate-functional coating". This structure endows the electrode with excellent mechanical stability and long-term operational durability, capable of withstanding physical erosion caused by severe bubble precipitation under high current density and corrosion under electrochemical environments, solving the pain points of easy peeling and poor stability of traditional composite electrodes.

[0017] Furthermore, the process of this invention combines nanoscale precision with macroscopic scalability, providing an innovative path for the industrial manufacturing of high-performance water electrolysis electrodes. The femtosecond laser processing technology employed allows for precise control of the spot diameter, scanning spacing, and energy, enabling the fabrication of stripe structures with periods of 50-500 micrometers—a precision difficult to achieve with traditional mechanical or chemical etching methods. This micrometer-level structural control optimizes the distribution of catalytic active sites and the size of bubble desorption channels on the electrode surface, directly improving intrinsic performance. Simultaneously, the entire process flow (coating, laser scanning, water immersion) is theoretically applicable to roll-to-roll or large-area scanning processing. The laser scanning speed is high (up to 1 cm / s), and water immersion processing is a batch operation, possessing the potential for large-scale continuous production. This method has broad applicability to substrate materials (foamed nickel, titanium, etc.) and active ingredients (nickel, cobalt, molybdenum, and noble metals, etc.), and by adjusting the precursor formulation and laser parameters, hydrogen evolution and oxygen evolution electrodes suitable for alkaline or proton exchange membrane electrolyzers can be flexibly customized. Therefore, this invention not only provides a high-performance electrode structure, but also a controllable, efficient, and universal fabrication solution that can take into account both cutting-edge performance and future industrialization needs.

[0018] This invention discloses a hydrophilic and aerophilic alternating stripe electrode with alternating, functionally specialized micro- and nano-stripes on its surface. The hydrophilic catalytic stripes are composed of transition metal nanoparticles generated in situ by laser and embedded in a stable hydrophilic oxide matrix, specifically responsible for providing high-density active sites and ensuring efficient supply of reactant ions. Adjacent aerophilic stripes are formed in situ through subsequent hydrolysis reactions, possessing low surface energy characteristics, and specifically responsible for providing low-adhesion escape channels for generated bubbles. This design, which physically separates but closely adjacent these two functions, allows the catalytic reaction and bubble desorption to proceed efficiently in their respective optimized microenvironments without interference. It breaks through the performance bottleneck of traditional electrodes from the source of material design, achieving micron-scale spatial decoupling and synergy between catalysis and desorption functions. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a process flow diagram of a method for preparing a hydrophilic and aerophilic alternating stripe electrode according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the electrode surface in an embodiment of the present invention; Figure 3 SEM images of the electrodes in an embodiment of the present invention; Figure 4 This is a diagram showing the distribution of electrode elements in an embodiment of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0022] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0023] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0024] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0025] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1 This invention discloses a method for preparing a hydrophilic-aerophilic alternating stripe electrode, comprising the following steps: S1, Preparation of composite precursor slurry: Mix hydrophilic precursor, gas-philic precursor and soluble transition metal salt, add solvent and dispersant to form a uniform composite slurry. Specifically, the hydrophilic precursor includes one or more of silica sol, tetrabutyl titanate, alumina sol, and zirconate ester, with a solid content of 5% to 40% in the composite slurry; the aerophilic precursor includes one or more of fluorosilanes (such as heptadecafluorodecyltrimethoxysilane), perfluorosulfonic acid resin, polytetrafluoroethylene emulsion, and fluoroacrylate, with a solid content of 2% to 30% in the composite slurry; the soluble transition metal salt is one or more of nitrates, chlorides, acetates, and acetylacetone salts, with the metal element including nickel, cobalt, iron, molybdenum, tungsten, iridium, and ruthenium, and the total concentration of the metal salt in the composite slurry (calculated as metal ions) is 0.01 to 2.0%. The solvent is one or more of deionized water, ethanol, isopropanol, N-methylpyrrolidone (NMP), and N,N-dimethylformamide (DMF); the dispersant is one or more of polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and sodium dodecylbenzenesulfonate (SDBS), and the addition amount is 0.1% to 5% of the total mass of the composite slurry; the dry matter mass ratio of the hydrophilic precursor to the aerophilic precursor is 1:5 to 5:1, preferably 1:2 to 2:1. The viscosity of the composite slurry is 10 to 5000 mPa·s (measured at 25°C).

[0027] S2, Slurry coating and pre-drying: The composite slurry is coated on the surface of a conductive substrate and then pre-dried to form a solid composite precursor film containing hydrophilic, gas-loving components and metal salts, thereby obtaining an electrode coated with the solid composite precursor film; Specifically, the conductive substrate is nickel foam, nickel felt, titanium foam, titanium mesh, carbon cloth, or carbon paper, with a thickness of 0.1~5mm and a porosity of 50%~98%; the slurry coating method includes scraping, spin coating, dip-coating, spraying, or screen printing, with a wet film thickness of 5~200 μm; the pre-drying temperature is 40~120℃, the drying time is 10 minutes to 12 hours, and the drying atmosphere is air or an inert atmosphere; the dry film thickness of the solid composite precursor film after pre-drying is 1~50 μm.

[0028] S3, femtosecond laser selective striping: A femtosecond laser system is used to perform array-type focused scanning on the electrode covered with the solid composite precursor film to form striped areas, thus completing the laser selective striping process. Specifically, a femtosecond laser system is used to perform array-focused scanning on electrodes coated with precursor films. Laser parameters are set as follows: pulse width in the femtosecond range, scan line spacing (i.e., the resulting stripe period) in the micrometer range, and instantaneous temperature micro-regions generated at each laser focal point. Within the laser-scanned stripe regions, ultra-high temperatures cause transient pyrolysis and sintering of the precursor. During this process, transition metal salts are reduced or transformed into catalytically active oxide / alloy nanoparticles; the hydrophilic precursor firmly bonds to the substrate, forming a stable hydrophilic catalytic composite phase. Meanwhile, the gas-philic precursor in this region is partially consumed or modified due to pyrolysis. The femtosecond laser has a center wavelength of 1030 nm, 515 nm, or 343 nm, and a pulse width of 10–500 fs; a single pulse energy of 0.1–100 μJ, and a repetition frequency of 1 kHz–1 MHz; a focused laser spot diameter of 1–20 μm, and a scanning line spacing (i.e., fringe period) of 50–500 μm, preferably 100–300 μm; a laser scanning speed of 1–10 mm / s, and a parallel straight scanning path; the instantaneous high-temperature micro-area temperature generated during laser scanning is >3000 K, and the high-temperature duration (heat-affected time) is 10. -9 ~10 -6 s; The width of the laser scanning area (stripes) is 100%~150% of the scanning line spacing.

[0029] S4, Water immersion treatment and gap region functionalization: The electrode after laser selective striping is subjected to water immersion treatment to obtain a hydrophilic and aerophilic alternating stripe electrode.

[0030] Specifically, the laser-treated electrode is immersed in water. In the gap region formed by laser scanning, the composite precursor film, which has not undergone high-temperature treatment, undergoes hydrolysis. During this process, soluble transition metal salts and hydrophilic components are dissolved and eluted; while the gas-philic precursor, through hydrolysis, forms a stable, gas-philic coating rich in low surface energy groups in situ on the substrate surface in the gap region. The medium used for the water immersion treatment is deionized water, ultrapure water, or a weakly acidic / weakly alkaline aqueous solution (pH 4~10), with a water temperature of 20~90℃, preferably 40~70℃; the water immersion treatment time is 0.5~24 hours, preferably 2~12 hours; preferably, ultrasonic oscillation or mechanical stirring can be used during the water immersion treatment to accelerate the dissolution and hydrolysis process, with an ultrasonic power of 50~500 W and a frequency of 20~40 kHz; after the water immersion treatment, the electrode needs to be rinsed with deionized water to remove residual soluble substances, and then dried at 40~120℃ for 0.5~5 hours; the final electrode surface has a width of 25~250 μm for both hydrophilic catalytic stripes and aerophilic stripes.

[0031] See Figure 2 This invention discloses a hydrophilic-hydrophilic alternating stripe electrode, wherein the surface of the electrode has alternating hydrophilic catalytic stripes and hydrophilic stripes; the width of both the hydrophilic catalytic stripes and the hydrophilic stripes is 25 μm to 250 μm. This invention achieves micron-scale spatial decoupling and synergy between catalysis and desorption functions, fundamentally resolving the inherent contradictions of traditional electrodes. Traditional electrode designs force a single active surface to simultaneously undertake two conflicting responsibilities: efficient catalysis and rapid bubble desorption. This forces the electrode to operate within a compromise between "hydrophilic" and "hydrophobic" properties, limiting its performance. This invention uses femtosecond laser processing to precisely define alternating, functionally specialized micro- and nano-stripes on the electrode surface. The hydrophilic catalytic stripes are composed of transition metal nanoparticles generated in situ by laser and embedded in a stable hydrophilic oxide matrix, specifically responsible for providing high-density active sites and ensuring efficient supply of reactant ions; while the adjacent hydrophilic stripes are formed in situ through subsequent hydrolysis reactions, possessing low surface energy characteristics, specifically responsible for providing low-adhesion escape channels for the generated bubbles. This design, which separates the two functions in physical space but keeps them closely adjacent, allows the catalytic reaction and bubble desorption to proceed efficiently in their respective optimized microenvironments without interfering with each other. It breaks through the performance bottleneck of traditional electrodes from the source of material design and achieves a synergistic effect of "1+1>2".

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0034] Example 1: The specific implementation process of this embodiment is as follows: First, at a dry matter mass ratio of 1:1, silica sol with a solid content of 20% is selected as the hydrophilic precursor, and heptadecafluorodecyltrimethoxysilane ethanol solution with a solid content of 15% is selected as the gas-philic precursor. These are mixed with soluble transition metal salts nickel nitrate and molybdenum chloride to prepare a composite slurry with a total metal ion concentration of 0.5 mol / L. 1% (mass fraction) of PVP is added to the slurry as a dispersant, and deionized water is added as a solvent. The final viscosity is 500 mPa·s (25℃).

[0035] Subsequently, the slurry was uniformly coated onto a nickel felt substrate with a thickness of 1 mm and a porosity of 95% using a blade coating method, forming a coating with a wet film thickness of approximately 50 μm. The coating was pre-dried in air at 80°C for 2 hours to obtain a solid composite precursor film with a dry film thickness of approximately 10 μm.

[0036] Next, an array-focused scanning was performed using a femtosecond laser system with a center wavelength of 515 nm, a pulse width of 100 fs, and a repetition rate of 100 kHz. The single-pulse energy was set to 10 μJ, and the focused spot diameter was 5 μm. The scanning path was a parallel straight line, the fringe spacing (fringe period) was 200 μm, and the scanning speed was 5 mm / s. During the scanning process, a transient temperature of 3900 K was generated at the focal point, lasting for approximately 10 seconds. -8 The micro-regional thermal effect of s causes nickel nitrate and molybdenum chloride in this region to pyrolyze into NiMo alloy nanoparticles, which then firmly bond with the silica sol matrix to form a hydrophilic catalytic phase.

[0037] Finally, the entire electrode was immersed in a weakly alkaline aqueous solution (pH 9) at 60°C for 6 hours. Simultaneously, under ultrasonic assistance at 200 W and 28 kHz, the untreated film layer in the stripe gap region underwent hydrolysis. Residual transition metal salts and some silicon components were dissolved and eluted, while the fluorinated silanes hydrolyzed and formed a stable aerophilic coating in situ. After removal, the electrode was rinsed with deionized water and dried at 80°C for 2 hours. The final electrode surface exhibited an alternating stripe structure, with the hydrophilic catalytic stripes approximately 100 μm wide. Figure 3Electrode element distribution diagram as follows Figure 4 As shown.

[0038] The hydrophilic-aerophilic alternating stripe electrode prepared by the above process exhibits excellent comprehensive performance in the high current density hydrogen evolution reaction. Under the test conditions of 1.0 M KOH and 60 °C, the hydrogen evolution overpotential of this electrode at a current density of 1000 mA / cm² is only 180 mV, which is significantly lower than that of the traditional homogeneous NiMo / nickel foam electrode (280 mV overpotential at the same loading) by 100 mV, indicating that the high activity of its hydrophilic catalytic stripes is fully utilized. At the same time, the aerophilic stripes effectively guide the rapid directional desorption of generated hydrogen bubbles, shortening the time for bubbles to completely detach from the electrode surface by about 70% at 500 mA / cm², significantly reducing mass transfer polarization caused by bubble coverage. After 200 hours of continuous operation at a current density of 500 mA / cm², the electrode showed almost no activity decay, and the overpotential increased by only about 5 mV, proving that the catalytic phase formed under femtosecond laser induction has a stable bond with the substrate, and that the hydrophilic / aerophilic binary structure remains stable during long-term operation, providing an efficient and reliable solution to the problem of bubble blockage at high current densities.

[0039] Example 2: A composite slurry with a total metal ion concentration of 0.01 mol / L was prepared by mixing aluminum sol (5% solids content) as a hydrophilic precursor and perfluorosulfonic acid resin ethanol solution (2% solids content) as a gas-philic precursor with soluble transition metal salts cobalt nitrate and ferric chloride at a dry matter mass ratio of 1:5. 0.1% (mass fraction) of SDBS was added to the slurry as a dispersant, and ethanol was added as a solvent, resulting in a final viscosity of 10 mPa·s (25℃).

[0040] Subsequently, this slurry was uniformly coated onto a carbon cloth substrate with a thickness of 0.1 mm and a porosity of 50% using an dip-coating method, forming a coating with a wet film thickness of approximately 5 μm. The coating was pre-dried in a nitrogen atmosphere at 40°C for 12 hours to obtain a solid composite precursor film with a dry film thickness of approximately 1 μm.

[0041] Next, an array-focused scanning was performed using a femtosecond laser system with a center wavelength of 1030 nm, a pulse width of 10 fs, and a repetition rate of 1 kHz. The single-pulse energy was set to 0.1 μJ, and the focused spot diameter was 1 μm. The scanning path was a parallel straight line, the fringe spacing was 50 μm, and the scanning speed was 1 mm / s. During the scanning process, a transient temperature of 3100 K was generated at the focal point, lasting for approximately 10 seconds. -9 The micro-region thermal effect of s.

[0042] Finally, the entire electrode was immersed in deionized water (pH 7) at 20°C for 0.5 hours, while simultaneously undergoing ultrasonic treatment at 50 W and 20 kHz. The untreated film layer in the stripe gap region hydrolyzed. Residual transition metal salts and some aluminum components were dissolved and eluted, while the perfluorosulfonic acid resin hydrolyzed to form a stable, gas-philic coating in situ. The electrode was then rinsed with deionized water and dried at 40°C for 5 hours. The final electrode surface exhibited an alternating stripe structure, with the hydrophilic catalytic stripes approximately 25 μm wide.

[0043] Example 3: A composite slurry with a total metal ion concentration of 2.0 mol / L was prepared by mixing zirconate ester with a solid content of 40% and polytetrafluoroethylene emulsion with a solid content of 30% as the hydrophilic precursor, at a dry matter mass ratio of 5:1. The mixture was also prepared with soluble transition metal salts ruthenium acetylacetone and iridium chloride. 5% (mass fraction) of PEG was added to the slurry as a dispersant, and N-methylpyrrolidone (NMP) was added as a solvent.

[0044] Subsequently, this slurry was uniformly coated onto a 5 mm thick titanium foam substrate with a porosity of 98% using screen printing, forming a wet film thickness of approximately 200 μm. The coating was pre-dried in air at 120°C for 10 minutes to obtain a solid composite precursor film with a dry film thickness of approximately 50 μm.

[0045] Next, an array-focused scanning was performed using a femtosecond laser system with a center wavelength of 343 nm, a pulse width of 500 fs, and a repetition rate of 1 MHz. The single-pulse energy was set to 100 μJ, and the focused spot diameter was 20 μm. The scanning path was a parallel straight line, the fringe spacing was 500 μm, and the scanning speed was 1000 mm / s. During the scanning process, a transient temperature of 4800 K was generated at the focal point, lasting for approximately 10 seconds. -6 The micro-region thermal effect of s.

[0046] Finally, the entire electrode was immersed in a weakly alkaline aqueous solution (pH 10) at 90°C for 24 hours. Simultaneously, under ultrasonic assistance at 500 W and 40 kHz, the untreated film layer in the stripe gap region underwent hydrolysis. Residual transition metal salts and some zirconium components were dissolved and eluted, while the hydrolyzed polytetrafluoroethylene formed a stable, gas-philic coating in situ. After removal, the electrode was rinsed with deionized water and dried at 120°C for 0.5 hours. The final electrode surface exhibited an alternating stripe structure, with the hydrophilic catalytic stripes approximately 250 μm wide.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a hydrophilic-aerophilic alternating stripe electrode, characterized in that, Includes the following steps: A hydrophilic precursor, a gas-philic precursor, and a soluble transition metal salt are mixed, and a solvent and dispersant are added to form a uniform composite slurry. The composite slurry is coated on the surface of a conductive substrate and then pre-dried to obtain an electrode coated with a solid composite precursor film. A femtosecond laser system is used to perform array-type focused scanning on the electrode covered with a solid composite precursor film, and the scanning forms a striped region to complete the laser selective striping process. Electrodes treated with laser selective striping are subjected to water immersion to obtain hydrophilic and aerophilic alternating stripe electrodes.

2. The method for preparing a hydrophilic-aerophilic alternating stripe electrode according to claim 1, characterized in that, The hydrophilic precursor includes one or more mixtures of silica sol, tetrabutyl titanate, alumina sol, and zirconate ester, and the solid content of the hydrophilic precursor in the composite slurry is 5% to 40%; the aerophilic precursor includes one or more mixtures of fluorinated silane, perfluorosulfonic acid resin, polytetrafluoroethylene emulsion, and fluorinated acrylate, and the solid content of the aerophilic precursor in the composite slurry is 2% to 30%; the soluble transition metal salt is one or more of nitrate, chloride, acetate, and acetylacetone salt, and the metal element in the soluble transition metal salt includes one or more of nickel, cobalt, iron, molybdenum, tungsten, iridium, and ruthenium, and the total concentration of the soluble transition metal salt in the composite slurry, calculated as metal ions, is 0.01 to 2.0 mol / L.

3. The method for preparing a hydrophilic-aerophilic alternating stripe electrode according to claim 1, characterized in that, The solvent is one or more of deionized water, ethanol, isopropanol, N-methylpyrrolidone, and N,N-dimethylformamide; the dispersant is one or more of polyvinylpyrrolidone, polyethylene glycol, and sodium dodecylbenzenesulfonate, and the amount of dispersant added is 0.1% to 5% of the total mass of the slurry; the dry matter mass ratio of the hydrophilic precursor to the aerophilic precursor is (1 to 5):(1 to 5); the viscosity of the composite slurry is 10 mPa·s to 5000 mPa·s.

4. The method for preparing a hydrophilic-aerophilic alternating stripe electrode according to claim 1, characterized in that, The conductive substrate is nickel foam, nickel felt, titanium foam, titanium mesh, carbon cloth, or carbon paper, with a thickness of 0.1 mm to 5 mm and a porosity of 50% to 98%. The coating method includes scraping, spin coating, dip coating, spraying, or screen printing, with a coating thickness of 5 μm to 200 μm.

5. The method for preparing a hydrophilic-aerophilic alternating stripe electrode according to claim 1, characterized in that, The pre-drying temperature is 40℃~120℃, the drying time is 10 minutes~12 hours, and the drying atmosphere is air or an inert atmosphere; the dry film thickness of the pre-dried solid composite precursor film is 1μm~50μm.

6. The method for preparing a hydrophilic-aerophilic alternating stripe electrode according to claim 1, characterized in that, The parameters of the femtosecond laser system are set as follows: the center wavelength of the femtosecond laser is 1030 nm, 515 nm, or 343 nm; the pulse width is 10~500 fs; the laser single pulse energy is 0.1 μJ~100 μJ; the repetition frequency is 1 kHz~1 MHz; the laser focused spot diameter is 1 μm~20 μm; the scanning line spacing is 50 μm~500 μm; the laser scanning speed is 1 mm / s~10 mm / s; the scanning path is a parallel straight line; the instantaneous high-temperature micro-area temperature generated during laser scanning is >3000 K; the high-temperature duration is 10... -9 s ~ 10 -6 s.

7. The method for preparing a hydrophilic-aerophilic alternating stripe electrode according to claim 1, characterized in that, The water immersion treatment uses deionized water, ultrapure water, or a weakly acidic / weakly alkaline aqueous solution as the medium, with a water temperature of 20℃ to 90℃; the water immersion treatment time is 0.5 hours to 24 hours.

8. The method for preparing a hydrophilic-aerophilic alternating stripe electrode according to claim 1, characterized in that, The water immersion process is supplemented by ultrasonic oscillation or mechanical stirring, wherein the ultrasonic power of the ultrasonic oscillation is 50W~500W and the frequency is 20kHz~40kHz.

9. The method for preparing a hydrophilic-aerophilic alternating stripe electrode according to claim 1, characterized in that, After the step of immersing the electrode after laser selective striping treatment in water, the method further includes rinsing the electrode with deionized water to remove residual soluble substances, and then drying it at 40℃~120℃ for 0.5 hours to 5 hours; finally, a hydrophilic and aerophilic alternating striped electrode is obtained.

10. A hydrophilic-aerophilic alternating stripe electrode, characterized in that, The electrode is prepared by the method described in any one of claims 1 to 9, wherein the surface of the electrode has alternating hydrophilic and aerophilic stripes; the width of both the hydrophilic and aerophilic stripes is 25 μm to 250 μm.

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