Photovoltaic coupling electrolysis hydrogen production chip, preparation method and stacked module thereof

Abstract

The application provides a composite ceramic-based photovoltaic coupling electrolytic hydrogen production chip, which comprises an anode current collecting substrate, an anode diffusion layer, an anode catalytic layer, a proton exchange membrane, a cathode catalytic layer, a cathode diffusion layer and a cathode current collecting substrate which are vertically and layerwisely arranged, the anode current collecting substrate and the cathode current collecting substrate comprise a Ti3AlC2 MAX phase ceramic core layer, a nano-diamond gradient composite layer and a passivation layer. The application further provides a preparation method of the photovoltaic coupling electrolytic hydrogen production chip. The application further provides a photovoltaic coupling electrolytic hydrogen production stacking module. The anode current collecting substrate and the cathode current collecting substrate of the application are integrated and have no adhesive structure, which greatly increases the overall structural strength and interface bonding force, and greatly improves the service life of the existing metal-based electrolytic cell. A full-link gradient mass transfer system from inside to outside and an in-situ hydrophilic and hydrophobic integrated flow field are formed, which can fully guide water vapor to enter and condensate water to discharge, and maintain the smoothness of the electrolysis reaction system, thereby greatly reducing the green hydrogen production cost.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic electrolysis hydrogen production technology, and in particular to photovoltaic coupled electrolysis hydrogen production chips, preparation methods and their stacking modules. Background Technology

[0002] Hydrogen energy, as a clean, low-carbon, diversified, and energy storage-oriented secondary energy source, is a core carrier for global energy structure transformation, deep industrial decarbonization, and the construction of new power systems. Relying on diverse production paths such as electricity, fossil raw materials, and industrial by-products, it can achieve cross-domain, long-term energy storage and cross-industry energy transmission, effectively addressing the pain points of intermittency and volatility in wind and solar power generation, and providing key support for large-scale new energy consumption.

[0003] Electrolysis of water to produce hydrogen is currently the core technology for the large-scale deployment of green hydrogen. It relies on renewable energy to drive an electrochemical reaction that splits water molecules, producing zero carbon emissions throughout the process. It can be coupled with green power resources such as photovoltaics and wind power to form photovoltaic-hydrogen and wind-hydrogen coupling systems. Based on the technical temperature and electrolyte system, it can be differentiated into several technical routes, including alkaline electrolysis, low-temperature proton exchange membrane electrolysis, medium-temperature proton exchange membrane electrolysis, and high-temperature solid oxide electrolysis. Among these, proton exchange membrane electrolysis, with its advantages of rapid start-up and shutdown, wide power adjustment range, adaptability to fluctuating renewable energy conditions, high gas purity, and strong system integration, has become the mainstream development direction for distributed green hydrogen, renewable energy-coupled hydrogen production, and high-end precision electrolysis scenarios. Medium-temperature proton exchange membrane electrolysis, because it can utilize photovoltaic waste heat / industrial low-pressure steam to compensate for reaction entropy changes, reduces the theoretical power consumption of lower-temperature electrolysis by more than 15%, making it particularly suitable for coupling with photovoltaic power generation to achieve hydrogen production. It is the core technology direction for distributed, low-cost green hydrogen production.

[0004] For example, Chinese invention patent CN120945399A discloses a Ti-Nb-Zr / MAX phase / Cr-CN multilayer composite coated bipolar plate and its preparation method. Using stainless steel / titanium alloy as the metal substrate, a multilayer coating structure is sequentially deposited on the surface, consisting of a Ti-Nb-Zr alloy transition layer, a MAX phase intermediate layer, and a Cr-CN nanocomposite surface layer. This structure is prepared by pulsed laser deposition and is used to improve the corrosion resistance and conductivity of the metal bipolar plate. Chinese invention patent CN115821300A discloses a proton exchange membrane (PEM) water electrolysis hydrogen production electrolyzer device. This device immerses the electrolyzer stack in the shell for electrolysis water, balancing the anode and cathode pressure differences through shell water pressure, thus reducing sealing requirements. It is designed for room-temperature PEM water electrolysis scenarios.

[0005] However, the aforementioned patents and other existing proton exchange membrane electrolysis hydrogen production technologies still have the following problems:

[0006] I. Existing electrolytic cells mainly use metal bipolar plates, which are prone to pitting corrosion and intergranular corrosion under acidic and oxygen-containing conditions at 120℃, resulting in a continuous operating life of less than 3000 hours. Current technologies usually address these issues by applying a corrosion-resistant ceramic coating to the surface of the metal bipolar plates. However, because an integrated ceramic matrix is ​​not formed, it cannot solve the problems of large differences in the thermal expansion coefficients of heterogeneous materials, cracking and delamination during thermal cycling, and soaring interfacial contact resistance. At the same time, the coating peeling problem also reduces the service life of the material.

[0007] II. In medium-temperature steam electrolysis at around 120℃, condensation forms in the catalyst layer due to water molecule migration and steam condensation, causing micropore blockage and hindering gas flow. Current technologies typically use additional hydrophilic / hydrophobic coatings to guide condensation out; however, these coatings are prone to peeling, have short lifespans, and lack a comprehensive, end-to-end water-vapor bidirectional synergistic control design, resulting in a 1A / cm² flow rate... 2 Electrolysis voltage is generally higher than 1.55V under current density, resulting in high power consumption.

[0008] III. Existing PEM electrolytic cells are all m 2 The large-size structure makes effective stacking difficult, requiring a complete redesign for power expansion. This results in high costs and difficulties in large-scale application, hindering its use in hydrogen production coupled with photovoltaic power plants. Furthermore, the lack of a unified standardized interface leads to incompatibility between products from different manufacturers, making it impossible to adapt to general-purpose stacking modules. Poor supply chain collaboration also prevents cost reduction through mass production. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a photovoltaic-coupled electrolytic hydrogen production chip, its preparation method, and its stacking module, which solves problems such as the metal plates being susceptible to corrosion, the lack of effective guidance for condensate discharge, and the difficulty in achieving large-scale stacking for scalability in existing technologies.

[0010] In a first aspect, the present invention proposes a photovoltaic coupled electrolytic hydrogen production chip based on composite ceramics, comprising a vertically stacked anode current collector substrate, an anode diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer, a cathode diffusion layer, and a cathode current collector substrate. The anode current collector substrate and the cathode current collector substrate are composite ceramic substrates, comprising a Ti3AlC2MAX phase ceramic core layer, a nanodiamond gradient composite layer grown in situ on the surface of the core layer, and a passivation layer grown in situ on the surface of the gradient composite layer. The anode current collector substrate and the cathode current collector substrate are integrally formed with a flow field on opposite sides.

[0011] The anode diffusion layer and the cathode diffusion layer are porous titanium fiber felt structures, with their pore size gradually decreasing from the side near the anode catalyst layer or the cathode catalyst layer to the side near the anode current collector or the cathode current collector.

[0012] The anode catalyst layer and the cathode catalyst layer are applied to two opposite surfaces of the proton exchange membrane by spraying and curing. The anode catalyst layer and the cathode catalyst layer have a gradient pore structure, and their pore size and porosity gradually increase from the side near the proton exchange membrane to the anode diffusion layer or the cathode diffusion layer.

[0013] The anode current collector and / or cathode current collector are provided with fluid interfaces and electrical interfaces on their sides, mechanical positioning structures at the four corners, and an encapsulation frame integrally formed on the outer edge; thus, the anode current collector and cathode current collector sequentially sandwich the anode diffusion layer, anode catalyst layer, proton exchange membrane, cathode catalyst layer, and cathode diffusion layer inside to form an integral closed structure, thereby constituting a chip as a whole;

[0014] The non-reactive regions at the edges of the anode current collector and / or cathode current collector integrate a ceramic-based photovoltaic direct-drive power module, which in turn integrates a sensor module.

[0015] Preferably, in the composite ceramic matrix, the thickness of the Ti3AlC2MAX phase ceramic core layer is 0.2mm-0.8mm, the thickness of the nanodiamond gradient composite layer is 5μm-15μm, and the thickness of the passivation layer is 0.5-1.5nm.

[0016] Furthermore, the inner wall of the anode current collector is provided with an anode flow field, which is a variable cross-section serpentine structure with a linearly increasing cross-sectional area and a linearly decreasing flow velocity along the flow direction; a superhydrophilic region is generated at the bottom through laser induction, and a superhydrophobic region is generated on the sidewalls, thereby forming a hydrophilic-hydrophobic partition in the vertical flow direction;

[0017] The inner wall of the cathode current collector is provided with a cathode flow field, which is a 3D microneedle structure. The microneedles are arranged in a forked pattern, and the surface of the microneedles is laser-induced to generate axial superhydrophobic water-conducting grooves, forming a hydrophilic-hydrophobic partition between the bottom surface of the flow field and the microneedles.

[0018] Preferably, the thickness of the anode diffusion layer and the cathode diffusion layer is 0.1mm-0.2mm, the large-pore side is a hydrophobic layer with a pore size of 10μm-20μm, and is doped with 25-35% polytetrafluoroethylene by mass; the small-pore side is a hydrophilic layer with a pore size of 0.5μm-2μm, and is doped with 3-7% polytetrafluoroethylene by mass.

[0019] Preferably, the proton exchange membrane is a YSZ nanowire-modified perfluorosulfonic acid composite membrane with a thickness of 10μm-15μm, wherein the amount of YSZ nanowires added is 4%-8% of the mass of the perfluorosulfonic acid resin; the anode catalyst layer is an IrO2-RuO2@TiO2 nanowire core-shell structure catalyst, and the cathode catalyst layer is a Pt / C@BN nanosheet catalyst.

[0020] Furthermore, the fluid interface includes a water vapor inlet, a hydrogen outlet, an oxygen outlet, and a condensate outlet; the electrical interface includes elastic conductive posts disposed on both sides of the anode current collector and / or the cathode current collector; and the mechanical interface includes positioning pin holes disposed at the four corners of the anode current collector and / or the cathode current collector.

[0021] Secondly, the present invention proposes a method for preparing the above-mentioned photovoltaic-coupled electrolytic hydrogen production chip, comprising the following steps:

[0022] S1. The Ti3AlC2 raw material powder is dry-pressed into a green body, and the Ti3AlC2MAX phase ceramic matrix is ​​prepared by high-temperature sintering in an argon atmosphere. The flow field, packaging frame, interface structure and mechanical positioning structure are integrally formed by laser milling. Then, the nanodiamond gradient composite layer is grown in situ by MPCVD process, and a passivation layer is generated on the surface of the gradient composite layer by oxygen plasma treatment. Finally, the in-situ hydrophilic and hydrophobic partitions are generated in the flow field by laser induction.

[0023] S2. A porous titanium fiber felt structure with an anode diffusion layer and a cathode diffusion layer is prepared by a double-layer sintering process.

[0024] S3. YSZ nanowires were modified with silane coupling agent and a modified perfluorosulfonic acid composite membrane was prepared by casting method. After activation treatment, a proton exchange membrane was obtained.

[0025] S4. Prepare anodic and cathode catalyst slurries separately, and use ultrasonic spraying process to prepare anodic and cathode catalyst layers on both sides of the proton exchange membrane prepared in step S3.

[0026] S5. After aligning the layers prepared in the above steps using a mechanical positioning structure, stack them together, encapsulate them by hot pressing and sintering the encapsulation frame, assemble the electrical interface and fluid interface in accordance with the interface structure position, and finally integrate the photovoltaic direct drive power module and sensor module to complete the chip fabrication.

[0027] Furthermore, in step S1, the green blank is placed in a graphite crucible and heated to 1300℃-1400℃ at a heating rate of 2-4℃ / min under argon atmosphere protection, and sintered at a constant temperature for 3-5 hours. Then, it is cooled to room temperature with the furnace at a rate of 1.5-2.5℃ / min to obtain a Ti3AlC2MAX phase ceramic matrix.

[0028] When depositing a gradient composite layer of nanodiamond using the MPCVD process, the diamond content gradually increases from 0% to 100% starting from the surface of the Ti3AlC2MAX phase ceramic matrix by adjusting the methane / hydrogen flow ratio from 0% to 5% to 10% to 15%.

[0029] Furthermore, in step S4, a three-step ultrasonic spraying process is adopted: the first layer of slurry has a solid content of 3%, the spraying temperature is 130℃, and the solution flow rate is 0.7mL / min; the second layer of slurry has a solid content of 5%, the spraying temperature is 140℃, and the solution flow rate is 1.1mL / min; the third layer of slurry has a solid content of 8%, the spraying temperature is 150℃, and the solution flow rate is 1.5mL / min.

[0030] Thirdly, the present invention also proposes a photovoltaic coupled electrolytic hydrogen production chip stacking module, which consists of several of the above-mentioned photovoltaic coupled electrolytic hydrogen production chips, which are tightly stacked by mechanical positioning structure and connectors, and connected in parallel to electrical and fluid inlet and outlet components through electrical interfaces and fluid interfaces.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The anode current collector and cathode current collector in this invention are composite ceramic substrates, comprising a Ti3AlC2MAX phase ceramic core layer, a nanodiamond gradient composite layer grown in situ on the surface of the core layer, and a passivation layer grown in situ on the surface of the gradient composite layer. The overall structure is an integrated, non-adhesive architecture, which greatly increases the overall structural strength and interfacial bonding force. The interfacial bonding force is ≥40MPa. After 1000 thermal cycles, there is no cracking or delamination. The corrosion current density under acidic conditions at 120℃ is <0.05μA / cm². 2 It has a continuous operating life of over 10,000 hours, which is more than three times longer than that of existing metal-based electrolytic cells. At the same time, it also reduces costs compared to the traditional method of using large amounts of Pt-based metal materials.

[0033] 2. In this invention, the anode and cathode catalyst layers, closely attached to the proton exchange membrane, have a gradient pore structure. The outer anode and cathode diffusion layers are porous titanium fiber felt structures. The outermost anode and cathode current collectors are integrally formed on opposite sides with a flow field. This creates a full-link gradient mass transfer system from the inside out, along with an in-situ hydrophilic / hydrophobic integrated flow field. This effectively guides water vapor in and condensate out, preventing pore blockage and maintaining the smooth operation of the electrolysis reaction system, achieving a flow rate of 1 A / cm². 2 Electrolysis voltage ≤ 1.42V at current density, DC power consumption ≤ 3.95kWh / Nm 3 H2 reduces power consumption by more than 12% compared to existing medium-temperature electrolyzers. Based on an annual production of 1,000 tons of green hydrogen, it can save more than 1.2 million kWh of electricity per year, significantly reducing the cost of green hydrogen production.

[0034] 3. In this invention, the anode current collector and cathode current collector are located in the flow field of the nanodiamond gradient composite layer. Through laser induction, hydrophilic and hydrophobic regions with an integral structure with the substrate are formed in situ. There is no additional coating, and there is no coating peeling. There is no performance degradation after 1000 hours of continuous operation. The lifespan is increased by more than 5 times compared with the existing coating modification scheme, which greatly reduces the equipment operation and maintenance cost and the operation and maintenance frequency is reduced by more than 80%.

[0035] 4. This invention establishes a full-link gradient mass transfer system. The anode and cathode catalytic layers provide a water-vapor separation interface, utilizing the pore size difference to create an initial capillary driving force, rapidly transporting water vapor to the reaction site. The cathode diffusion layer and anode diffusion layer are symmetrically designed, forming a 1.5 kPa capillary pressure gradient, continuously drawing condensate into the flow field layer. The flow field of the anode current collector substrate exhibits an increasing cross-sectional area and decreasing velocity along the flow direction. Combined with the in-situ partitioning of the bottom superhydrophilic and sidewall superhydrophobic components, and the gravity assistance of the vertical layout, condensate is rapidly collected and discharged. The flow field of the cathode current collector substrate features 3D microneedle-like superhydrophobic water-guiding channels, enabling rapid separation and discharge of hydrogen and condensate. Ultimately, this achieves bidirectional, directional, high-speed water vapor-condensate transfer.

[0036] 5. This invention replaces the traditional electrolyzer with a standardized chip design. Combined with standardized electrical, fluid, and mechanical interfaces, it enables automated modular stacking with a power scaling linearity >99%. The unit cost of hydrogen production equipment is reduced by more than 60% compared to traditional electrolyzers. After mass production, the cost per chip can be reduced to below 50 yuan, making it suitable for low-cost deployment in distributed scenarios. Standardized stacking allows for linear power scaling from 100W to 1MW, adapting to various applications including distributed photovoltaic hydrogen production, industrial byproduct steam coupled hydrogen production, off-grid photovoltaic hydrogen storage, and hydrogen production at hydrogen refueling stations. No customized design is required, and project delivery cycles are shortened by more than 70%. Attached Figure Description

[0037] Figure 1 This is a schematic cross-sectional view of the chip structure according to an embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of the water vapor directional transport principle of the full-link gradient mass transfer system according to an embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram of a stacked module according to an embodiment of the present invention.

[0040] In the above figures: 1. Anode current collector substrate; 2. Anode diffusion layer; 3. Anode catalyst layer; 4. Proton exchange membrane; 5. Cathode catalyst layer; 6. Cathode diffusion layer; 7. Cathode current collector substrate; 8. Flow field. Detailed Implementation

[0041] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0042] Example 1:

[0043] like Figure 1 , 2 As shown, the photovoltaic-coupled electrolytic hydrogen production chip based on composite ceramics in this embodiment includes a vertically stacked anode current collector 1, an anode diffusion layer 2, an anode catalyst layer 3, a proton exchange membrane 4, a cathode catalyst layer 5, a cathode diffusion layer 6, and a cathode current collector 7. The anode current collector 1 and the cathode current collector 7 are composite ceramic substrates, including a Ti3AlC2MAX phase ceramic core layer, a nanodiamond gradient composite layer grown in situ on the surface of the core layer, and a passivation layer grown in situ on the surface of the gradient composite layer. A flow field 8 is integrally formed on one side of the anode current collector 1 and the cathode current collector 7.

[0044] The Ti3AlC2MAX phase ceramic core layer has an electrical conductivity ≥5×10⁻⁶ at 25℃. 6 With a current-to-weight ratio (S / m) comparable to metallic copper, efficient current collection can be achieved without an additional conductive layer; thermal conductivity ≥170W / (m·K) ensures uniform temperature distribution on the chip, preventing localized overheating; coefficient of thermal expansion 9.0×10⁻⁶. -6 The coefficient of thermal expansion (COP) of the nanodiamond-coated proton exchange membrane is ≥95% compatible with that of the perfluorosulfonic acid proton exchange membrane, and the COPs of the positive and negative electrode substrates are 100% identical, completely eliminating thermal stress during the -40℃ to 150℃ thermal cycling process. The nanodiamond gradient composite layer and the Ti3AlC2MAX phase ceramic core layer are metallurgically bonded with a bonding strength ≥40MPa, eliminating the risk of detachment. After 1000 thermal cycles, the interfacial bonding strength retention rate is ≥98%. The passivation layer combines high conductivity with superior corrosion resistance, exhibiting a corrosion current density <0.05μA / cm² under acidic fluorine-containing conditions at 120℃ and 1.6V vs. RHE. 2 Surface contact resistance <1mΩ·cm 2 It reduces the corrosion current of titanium alloy current collectors by more than three orders of magnitude compared to existing titanium alloy current collectors.

[0045] Specifically, the anode flow field has a variable cross-section serpentine structure with a narrow inlet of 0.6 mm, an outlet width of 0.9 mm, a channel depth of 0.3 mm, and a ridge width of 0.5 mm. The cross-sectional area of ​​the channel increases linearly along the flow direction, while the flow velocity decreases linearly. A superhydrophilic region (contact angle θ = 12° ± 3°) is induced at the bottom of the channel by a femtosecond laser, and a superhydrophobic region (contact angle θ = 152° ± 3°) is induced on the sidewall of the channel, forming a hydrophilic-hydrophobic gradient design.

[0046] The cathode flow field has a 3D microneedle structure, integrally milled, with a microneedle density of 150 needles / cm. 2The needle is 1.0 mm high, with a base diameter of 0.4 mm and a tip diameter of 0.1 mm. The microneedles are arranged in a forked pattern with a center-to-center distance of 1.0 mm between adjacent microneedles. The surface of the microneedles is laser-induced to generate axial superhydrophobic water-conducting grooves with a depth of 0.2 mm, a width of 0.15 mm, and a contact angle θ = 148° ± 5°.

[0047] The anode diffusion layer 2 and the cathode diffusion layer 6 are porous titanium fiber felt structures, with their pore size gradually decreasing from the side near the anode catalyst layer 3 or the cathode catalyst layer 5 to the side near the anode current collector 1 or the cathode current collector 7.

[0048] The anode catalyst layer 3 and the cathode catalyst layer 5 are applied to the two opposite surfaces of the proton exchange membrane 4 by spraying and curing. The anode catalyst layer 3 and the cathode catalyst layer 5 have a gradient pore structure, and their pore size and porosity gradually increase from the side near the proton exchange membrane 4 to the side of the anode diffusion layer 2 or the cathode diffusion layer 6.

[0049] The anode current collector 1 and / or cathode current collector 7 are provided with fluid interfaces and electrical interfaces on their sides, and mechanical positioning structures are provided at the four corners. An encapsulation frame is integrally formed on the outer edge. This allows the anode current collector 1 and cathode current collector 7 to sequentially sandwich the anode diffusion layer 2, anode catalyst layer 3, proton exchange membrane 4, cathode catalyst layer 5, and cathode diffusion layer 6 inside to form an integral closed structure, thereby constituting a chip as a whole.

[0050] A ceramic-based photovoltaic direct-drive power module (not shown) is integrated into the non-reactive region at the edge of the anode current collector substrate 1 and / or the cathode current collector substrate 7, and a sensor module (not shown) is integrated inside. The photovoltaic direct-drive power module is integrated into the non-reactive region at the edge of the anode current collector substrate and the cathode current collector substrate using low-temperature co-fired ceramic (LTCC) technology, without additional volume occupation; the circuit topology is a non-isolated Buck-Boost topology, with an input voltage of 20-60V DC, an output voltage of 10-30V DC, and a rated output current of 5A; it integrates a hardware-based MPPT acceleration unit and an electrolysis-condition dynamic response PID unit, and implements disturbance observation method MPPT tracking with pure hardware logic, with a response delay of <1μs and a conversion efficiency of >99.6%, eliminating 8%-10% of the energy loss of traditional inverter stages. The sensor module employs a MEMS passive sensor array, integrally laser-processed with the anode current collector and / or cathode current collector, embedded between the flow field and diffusion layer, and completely electrically isolated from the power circuit. It includes a platinum resistance temperature sensor (located at the center and four corners of the reaction area, with an accuracy of ±0.3℃), a voltage monitoring electrode, a capacitive humidity sensor (located at the fluid inlet and outlet, with an accuracy of ±2%RH), and a piezoresistive pressure sensor (with an accuracy of ±0.5%FS). All sensor signal leads are laid along the edge of the substrate and led out to the signal pins of a standardized electrical interface, realizing single-chip-level precise monitoring and fault early warning.

[0051] The chip prepared in this embodiment is based on the following specifications, and the specific method is as follows:

[0052] (1) Using 99.2% pure Ti3AlC2 powder, adding 3wt% yttrium oxide sintering aid, anhydrous ethanol as solvent, and PVB as binder, ball milling for 24h to obtain a uniform slurry, spray granulation, and dry pressing to prepare a 0.6mm thick green body, forming pressure 200MPa, holding time 30s; using ultraviolet laser to pre-etch tenon and tenon positioning structure, flow field profile, and interface structure on the surface of the green body, with positioning accuracy ±10μm; placing the green body in a graphite crucible, protecting it with a high-purity argon atmosphere, heating to 1350℃ at a heating rate of 3℃ / min, sintering at a constant temperature for 4h, and then cooling to room temperature with the furnace at a rate of 2℃ / min to obtain a Ti3AlC2MAX phase ceramic matrix with a thickness of 0.5mm; using five-axis femtosecond laser milling (laser wavelength 1030nm, pulse width 300fs, repetition frequency 100kHz), integrally processing a variable cross-section serpentine flow field on the matrix, 3D microneedle flow field, fluid interface, and positioning pin hole were fabricated with a machining accuracy of ±5μm. After processing, the substrate was ultrasonically cleaned with anhydrous ethanol for 10 min and dried with high-purity nitrogen. A 10μm thick nanodiamond gradient composite layer was grown in situ on all surfaces of the substrate using MPCVD technology. The microwave power was 3kW, the deposition temperature was 800℃, the deposition pressure was 4kPa, the stage bias was -150V, the stage rotation speed was 10rpm, the pulse period was 10μs, and the deposition time was 2h. The diamond content was gradually increased from 0% to 100% by adjusting the methane / hydrogen flow rate ratio from 0% to 5% to 10% to 15%. The substrate surface was treated with oxygen plasma for 10 min at a radio frequency power of 200W and an oxygen flow rate of 50sccm to generate a 1nm thick CO-Ti passivation layer in situ. Finally, a femtosecond laser was used to induce the formation of the passivation layer (laser wavelength 1030nm, pulse width 200fs, energy density 3.2J / cm²). 2 (Scanning speed 500 mm / s) to generate superhydrophilic / superhydrophobic regions in situ in the designated area of ​​the flow channel, thus completing the preparation of composite ceramic matrices in the anode current collector and cathode current collector.

[0053] (2) A porous titanium fiber felt with anode diffusion layer and cathode diffusion layer was prepared by double-layer sintering process. The total thickness was 0.15 mm. The pore size of the macropore layer was 15 μm and the PTFE content was 30%. The pore size of the micropore layer was 1 μm and the PTFE content was 5%. The sintering temperature was 1100℃, and the argon atmosphere was protected for 2 hours.

[0054] (3) YSZ nanowires were prepared by hydrothermal method. Surface modification was performed using KH550 silane coupling agent. After modification, the nanowires were dispersed in DMAc solvent. The ultrasonic power was 200W, the dispersion time was 30min, and the temperature was controlled at ≤10℃ in an ice-water bath. Short-chain perfluorosulfonic acid resin was added to prepare a casting solution with a solid content of 15%, and the solution was stirred for 24h. A biofilm was prepared using a doctor blade coating process with a doctor blade gap of 20μm and a coating speed of 2m / min. The biofilm was pre-baked at 60℃ for 30min and vacuum dried at 120℃ for 2h. Activation was performed with 5% dilute sulfuric acid at 80℃ for 2h, and the biofilm was rinsed with deionized water until neutral to obtain a 12μm thick composite membrane with 6% YSZ added. A proton exchange membrane was obtained.

[0055] (4) Preparation of IrO2-RuO2@TiO2 anode catalyst and Pt / C@boron nitride cathode catalyst slurries: graded slurries with solid contents of 3%, 5%, and 8% were prepared respectively. These slurries were coated on both sides of the composite membrane using a three-step ultrasonic spraying process. The anode loading was 0.3 mg / cm³. 2 Cathode loading 0.1 mg / cm 2 A gradient pore structure is formed, and the coating process is controlled with an accuracy of ±1μm. The three-step ultrasonic spraying process is as follows: the first layer has a solid content of 3%, a spraying temperature of 130℃, and a solution flow rate of 0.7mL / min; the second layer has a solid content of 5%, a spraying temperature of 140℃, and a solution flow rate of 1.1mL / min; and the third layer has a solid content of 8%, a spraying temperature of 150℃, and a solution flow rate of 1.5mL / min. A proton exchange membrane with coated anode and cathode catalyst layers is obtained.

[0056] (5) The anode current collector substrate, anode diffusion layer, proton exchange membrane with catalyst coating, cathode diffusion layer, and cathode current collector substrate are stacked sequentially, with the four corner positioning pin holes aligned to an alignment accuracy of ±20μm; the integrated PEEK packaging frame is fitted in, and hot-pressed at 130℃ and 2.5MPa for 10min; standardized fluid / electrical interfaces are assembled, and the on-chip photovoltaic direct-drive power module and MEMS sensor array are integrated using LTCC process to complete chip fabrication. The overall helium leak detection rate of the chip is <5×10 -7 Pa·m 3 / s, insulation class >1500V.

[0057] The test results of the chip product in this embodiment are as follows: at 120℃ and 1A / cm² 2 At the specified current density, the electrolysis voltage is 1.41V, and the DC power consumption is 3.92kWh / Nm³. 3 H2, Faraday efficiency 99.8%; after 1000 thermal cycles, interfacial adhesion retention rate 98.1%; corrosion current density under acidic conditions at 120℃ 0.042μA / cm² 2The performance degradation rate after 1000 hours of continuous operation is <1%; the photovoltaic direct drive conversion efficiency is 99.7%, the MPPT response delay is 0.8μs, and the photovoltaic absorption rate is 98.7%; the contact angle at the bottom of the anode channel is 11.2°, the contact angle on the sidewall is 153.5°, the contact angle of the cathode microneedle groove is 147.8°, and the contact angle change rate after 1000 hours of operation is <2%.

[0058] like Figure 3 As shown, based on the aforementioned chip product, this embodiment presents a photovoltaic-coupled electrolytic hydrogen production chip stacking module, consisting of several of the aforementioned photovoltaic-coupled electrolytic hydrogen production chips, tightly stacked using a mechanical positioning structure and connectors, and connected in parallel to electrical and fluid inlet / outlet components via electrical and fluid interfaces. The specific design is as follows:

[0059] Fluid Interfaces: Four standardized fluid interfaces are provided: water vapor inlet, hydrogen outlet, oxygen outlet, and condensate outlet. The interface diameter is 2mm, and the center distance tolerance is ±0.05mm. Each interface is equipped with a standardized φ3mm×0.5mm fluororubber O-ring sealing groove. When multiple chips are stacked, a common fluid manifold is automatically formed. Based on the optimized design of the flow resistance network model, it can ensure that when 1-1000 chips are stacked, the deviation of hydrogen and water vapor flow rate of a single chip is <3%, and the standard deviation of flow distribution is <3%, which is better than the industry-standard 5%.

[0060] Electrical interface: Standardized gold-plated flexible conductive pillars are set, with a diameter of 1mm, a height of 1.5mm, and a spacing of 2.54mm. There are 8 power pins and 8 signal pins, and the pin definitions are completely unified. A comb-shaped grid current collection design is adopted, which automatically realizes series and parallel electrical connection when multiple chips are stacked. The single contact resistance is <1mΩ and the power expansion linearity is >99%.

[0061] Mechanical interface: The chip is equipped with φ2mm high-precision positioning pin holes at the four corners, with a positioning accuracy of ±5μm and a hole position tolerance of ±0.02mm, which is compatible with automated stacking production lines and ensures the alignment accuracy when stacking multiple chips.

[0062] Example 2:

[0063] The chip prepared in this embodiment is of ultra-thin specification, and its preparation method is basically the same as that in Example 1, except that:

[0064] (1) Using 99.2% pure Ti3AlC2 powder, adding 3wt% yttrium oxide sintering aid, anhydrous ethanol as solvent, and PVB as binder, ball milling for 24h to obtain a uniform slurry, spray granulation, and dry pressing to prepare a 0.25mm thick green body, forming pressure 200MPa, holding time 30s; using ultraviolet laser to pre-etch tenon and tenon positioning structure, flow field profile, and interface structure on the surface of the green body, with positioning accuracy ±10μm; placing the green body in a graphite crucible, protecting it with a high-purity argon atmosphere, heating to 1300℃ at a heating rate of 2℃ / min, sintering at a constant temperature for 3h, and then cooling to room temperature with the furnace at a rate of 1.5℃ / min to obtain a MAX phase ceramic matrix with a thickness of 0.2mm; using five-axis femtosecond laser milling (laser wavelength 1030nm, pulse width 300fs, repetition frequency 100kHz), integrally processing a variable cross-section serpentine flow field and 3D on the matrix. The microneedle flow field, fluid interface, and positioning pin holes were machined with a precision of ±5μm. After machining, the substrate was ultrasonically cleaned with anhydrous ethanol for 10 min and dried with high-purity nitrogen. A 5μm thick nanodiamond gradient composite layer was grown in situ on all surfaces of the substrate using MPCVD technology. The microwave power was 3kW, the deposition temperature was 800℃, the deposition pressure was 4kPa, the stage bias was -150V, the stage rotation speed was 10rpm, the pulse period was 10μs, and the deposition time was 1h. The diamond content was gradually increased from 0% to 100% by adjusting the methane / hydrogen flow ratio from 0% to 5% to 10% to 15%. The substrate surface was treated with oxygen plasma for 5 min at a radio frequency power of 200W and an oxygen flow rate of 50sccm to generate a 0.5nm thick CO-Ti passivation layer in situ. Finally, a femtosecond laser was used to induce the formation of the passivation layer (laser wavelength 1030nm, pulse width 200fs, energy density 3.2J / cm²). 2 (Scanning speed 500 mm / s) to generate superhydrophilic / superhydrophobic regions in situ in the designated area of ​​the flow channel, thus completing the preparation of the composite ceramic matrix.

[0065] (2) A porous titanium fiber felt was prepared by a double-layer sintering process with a total thickness of 0.1 mm, a macropore layer with a pore size of 10 μm and a PTFE content of 25%, a micropore layer with a pore size of 0.5 μm and a PTFE content of 3%, a sintering temperature of 1100℃, an argon atmosphere protection, and a holding time of 2 h.

[0066] (3) YSZ nanowires were prepared by hydrothermal method. KH550 silane coupling agent was used for surface modification. After modification, the nanowires were dispersed in DMAc solvent. The ultrasonic power was 200W and the dispersion time was 30min. The temperature was controlled at ≤10℃ in an ice-water bath. Short-chain perfluorosulfonic acid resin was added to prepare a casting solution with a solid content of 15% and stirred for 24h. A film was prepared by blade coating process with a blade gap of 20μm and a coating speed of 2m / min. The film was pre-baked at 60℃ for 30min and vacuum dried at 120℃ for 2h. The film was activated with 5% dilute sulfuric acid at 80℃ for 2h and rinsed with deionized water until neutral to obtain a 10μm thick composite film with 4% YSZ added.

[0067] Performance test results of the product in this embodiment: 120℃, 1A / cm 2 At the specified current density, the electrolysis voltage is 1.42V, and the DC power consumption is 3.94kWh / Nm³. 3 H2; flexural strength 168MPa, no cracking or delamination after 1000 cycles of hot and cold; volumetric power density is 2.9 times higher than the basic specification.

[0068] Example 3:

[0069] The chip prepared in this embodiment is a thickened specification for high-load operation, and its preparation method is basically the same as that in Example 1, except that:

[0070] (1) Using 99.2% pure Ti3AlC2 powder, adding 3wt% yttrium oxide sintering aid, anhydrous ethanol as solvent, and PVB as binder, ball milling for 24h to obtain a uniform slurry, spray granulation, and dry pressing to prepare a 1.0mm thick green body, forming pressure 200MPa, holding time 30s; using ultraviolet laser to pre-etch tenon positioning structure, flow field profile, and interface structure on the surface of the green body, with positioning accuracy ±10μm; placing the green body in a graphite crucible, protecting it with a high-purity argon atmosphere, heating to 1400℃ at a heating rate of 4℃ / min, sintering at a constant temperature for 5h, and then cooling to room temperature with the furnace at a rate of 2.5℃ / min to obtain a MAX phase ceramic matrix with a thickness of 0.8mm; using five-axis femtosecond laser milling (laser wavelength 1030nm, pulse width 300fs, repetition frequency 100kHz), integrally processing a variable cross-section serpentine flow field and 3D microneedles on the matrix. The flow field, fluid interface, and positioning pin holes were machined with a precision of ±5μm. After machining, the substrate was ultrasonically cleaned with anhydrous ethanol for 10 minutes and dried with high-purity nitrogen. A 15μm thick nanodiamond gradient composite layer was grown in situ on all surfaces of the substrate using MPCVD technology. The microwave power was 3kW, the deposition temperature was 800℃, the deposition pressure was 4kPa, the stage bias was -150V, the stage rotation speed was 10rpm, the pulse period was 10μs, and the deposition time was 3h. The diamond content was gradually increased from 0% to 100% by adjusting the methane / hydrogen flow rate ratio from 0% to 5% to 10% to 15%. The substrate surface was treated with oxygen plasma for 15 minutes at a radio frequency power of 200W and an oxygen flow rate of 50sccm to generate a 1.5nm thick CO-Ti passivation layer in situ. Finally, a femtosecond laser was used to induce the formation of the passivation layer (laser wavelength 1030nm, pulse width 200fs, energy density 3.2J / cm²). 2 (Scanning speed 500 mm / s) to generate superhydrophilic / superhydrophobic regions in situ in the designated area of ​​the flow channel, thus completing the preparation of the composite ceramic matrix.

[0071] (2) A porous titanium fiber felt was prepared by a double-layer sintering process with a total thickness of 0.2 mm. The macropore layer had a pore size of 20 μm and a PTFE content of 35%, while the micropore layer had a pore size of 2 μm and a PTFE content of 7%. The sintering temperature was 1100℃, and the sintering was protected by an argon atmosphere for 2 hours.

[0072] (3) YSZ nanowires were prepared by hydrothermal method. KH550 silane coupling agent was used for surface modification. After modification, the nanowires were dispersed in DMAc solvent. The ultrasonic power was 200W and the dispersion time was 30min. The temperature was controlled at ≤10℃ in an ice-water bath. Short-chain perfluorosulfonic acid resin was added to prepare a casting solution with a solid content of 15% and stirred for 24h. A film was prepared by blade coating process with a blade gap of 20μm and a coating speed of 2m / min. The film was pre-baked at 60℃ for 30min and vacuum dried at 120℃ for 2h. The film was activated with 5% dilute sulfuric acid at 80℃ for 2h and rinsed with deionized water until neutral to obtain a 15μm thick composite film with a YSZ addition of 86%.

[0073] Performance test results of the product in this embodiment: 120℃, 2A / cm 2 At the specified current density, the electrolysis voltage is 1.51V, and the DC power consumption is 4.15kWh / Nm³. 3 H2; performance degradation rate of <2% after 1000 hours of continuous operation, suitable for high-load industrial hydrogen production scenarios.

[0074] Comparative Example 1:

[0075] The technical solution adopts the existing Chinese invention patent, publication number CN120945399A, entitled "A Ti-Nb-Zr / MAX phase / Cr-CN multilayer composite coated bipolar plate and its preparation method".

[0076] Comparative Example 2:

[0077] The technical solution adopted is from an existing Chinese invention patent, publication number CN115821300A, entitled "A Proton Exchange Membrane Water Electrolysis Hydrogen Production Electrolyzer Device".

[0078] Comparative Example 3:

[0079] The rest of this comparative example is the same as that in Example 1, except that: in step (2), the pore size of the porous titanium fiber felt is consistent and is 10 μm; PTFE is evenly distributed and has a content of 10%.

[0080] Comparative Example 4:

[0081] The rest of this comparative example is the same as that in Example 1, except that the hydrophilic / hydrophobic partitions were not generated by laser induction in step (1).

[0082] The parameters of the products from Example 1 and Comparative Examples 1-4 were compared, and the results are shown in Table 1:

[0083]

[0084] Table 1

[0085] The following conclusions can be drawn from Table 1:

[0086] 1. The MAX phase-nanodiamond gradient composite integrated matrix of the present invention, compared with the metal matrix MAX phase coating scheme of patent CN120945399A, reduces the corrosion current density by one order of magnitude and the attenuation rate after 1000 hours of operation by more than 94%, completely solving the problems of metal matrix corrosion and coating peeling, and greatly improving corrosion resistance and service life.

[0087] 2. The integrated non-adhesive structure of the present invention, compared with the conventional metal PEM electrolytic cell solution of patent CN115821300A, improves the interface bonding retention rate by 43.8% after 1000 thermal cycles and reduces the corrosion current density by 3 orders of magnitude, thus solving the problems of interface delamination and thermal mismatch in traditional technology.

[0088] 3. The full-link gradient mass transfer system is the core to overcome the energy efficiency bottleneck. For chips without a gradient system, the electrolysis voltage increases by more than 12%, which proves the synergistic effect of the present invention.

[0089] 4. Comparative Example 4 verifies the core role of in-situ hydrophilic / hydrophobic modification by laser: Under the same substrate and the same flow channel structure, the chip without in-situ hydrophilic / hydrophobic modification has a condensate coverage rate of up to 28% in the flow channel. In comparison, the 1A / cm in Example 1... 2 With an increase of 0.11V in electrolysis voltage, the performance degradation rate after 1000 hours of operation is improved by more than 15 times, significantly improving the drainage defects of traditional technology.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, 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 photovoltaic-coupled electrolytic hydrogen production chip based on composite ceramics, comprising a vertically stacked anode current collector substrate, an anode diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer, a cathode diffusion layer, and a cathode current collector substrate, characterized in that: The anode current collector and cathode current collector are composite ceramic substrates, including a Ti3AlC2MAX phase ceramic core layer, a nanodiamond gradient composite layer grown in situ on the surface of the core layer, and a passivation layer grown in situ on the surface of the gradient composite layer. The anode current collector and cathode current collector are integrally formed on opposite sides with a flow field. The anode diffusion layer and the cathode diffusion layer are porous titanium fiber felt structures, with their pore size gradually decreasing from the side near the anode catalyst layer or the cathode catalyst layer to the side near the anode current collector or the cathode current collector. The anode catalyst layer and the cathode catalyst layer are applied to two opposite surfaces of the proton exchange membrane by spraying and curing. The anode catalyst layer and the cathode catalyst layer have a gradient pore structure, and their pore size and porosity gradually increase from the side near the proton exchange membrane to the anode diffusion layer or the cathode diffusion layer. The anode current collector and / or cathode current collector are provided with fluid interfaces and electrical interfaces on their sides, mechanical positioning structures at the four corners, and an encapsulation frame integrally formed on the outer edge; thus, the anode current collector and cathode current collector sequentially sandwich the anode diffusion layer, anode catalyst layer, proton exchange membrane, cathode catalyst layer, and cathode diffusion layer inside to form an integral closed structure, thereby constituting a chip as a whole; The non-reactive regions at the edges of the anode current collector and / or cathode current collector integrate a ceramic-based photovoltaic direct-drive power module, which in turn integrates a sensor module.

2. The photovoltaic-coupled electrolytic hydrogen production chip based on composite ceramics as described in claim 1, characterized in that: In the composite ceramic matrix, the thickness of the Ti3AlC2MAX phase ceramic core layer is 0.2mm-0.8mm, the thickness of the nanodiamond gradient composite layer is 5μm-15μm, and the thickness of the passivation layer is 0.5-1.5nm.

3. The photovoltaic-coupled electrolytic hydrogen production chip based on composite ceramics as described in claim 1, characterized in that: The inner wall of the anode current collector is provided with an anode flow field, which is a variable cross-section serpentine structure with a linearly increasing cross-sectional area and a linearly decreasing flow velocity along the flow direction; a superhydrophilic region is generated at the bottom through laser induction, and a superhydrophobic region is generated on the sidewalls, thereby forming a hydrophilic-hydrophobic partition in the vertical flow direction; The inner wall of the cathode current collector is provided with a cathode flow field, which is a 3D microneedle structure. The microneedles are arranged in a forked pattern, and the surface of the microneedles is laser-induced to generate axial superhydrophobic water-conducting grooves, forming a hydrophilic-hydrophobic partition between the bottom surface of the flow field and the microneedles.

4. The photovoltaic-coupled electrolytic hydrogen production chip based on composite ceramics as described in claim 1, characterized in that: The thickness of the anode diffusion layer and the cathode diffusion layer is 0.1mm-0.2mm. The side with large pores is a hydrophobic layer with a pore size of 10μm-20μm and is doped with 25-35% polytetrafluoroethylene by mass. The side with small pores is a hydrophilic layer with a pore size of 0.5μm-2μm and is doped with 3-7% polytetrafluoroethylene by mass.

5. The photovoltaic-coupled electrolytic hydrogen production chip based on composite ceramics as described in claim 1, characterized in that: The proton exchange membrane is a YSZ nanowire-modified perfluorosulfonic acid composite membrane with a thickness of 10μm-15μm, wherein the amount of YSZ nanowires added is 4%-8% of the mass of the perfluorosulfonic acid resin; the anode catalyst layer is an IrO2-RuO2@TiO2 nanowire core-shell structure catalyst, and the cathode catalyst layer is a Pt / C@BN nanosheet catalyst.

6. The photovoltaic-coupled electrolytic hydrogen production chip based on composite ceramics as described in claim 1, characterized in that: The fluid interface includes a steam inlet, a hydrogen outlet, an oxygen outlet, and a condensate outlet; the electrical interface includes elastic conductive posts disposed on both sides of the anode current collector and / or the cathode current collector; the mechanical interface includes positioning pin holes disposed at the four corners of the anode current collector and / or the cathode current collector.

7. A method for preparing a photovoltaic-coupled electrolytic hydrogen production chip as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. The Ti3AlC2 raw material powder is dry-pressed into a green body, and the Ti3AlC2MAX phase ceramic matrix is ​​prepared by high-temperature sintering in an argon atmosphere. The flow field, packaging frame, interface structure and mechanical positioning structure are integrally formed by laser milling. Then, the nanodiamond gradient composite layer is grown in situ by MPCVD process, and a passivation layer is generated on the surface of the gradient composite layer by oxygen plasma treatment. Finally, the in-situ hydrophilic and hydrophobic partitions are generated in the flow field by laser induction. S2. A porous titanium fiber felt structure with an anode diffusion layer and a cathode diffusion layer is prepared by a double-layer sintering process. S3. YSZ nanowires were modified with silane coupling agent and a modified perfluorosulfonic acid composite membrane was prepared by casting method. After activation treatment, a proton exchange membrane was obtained. S4. Prepare anodic and cathode catalyst slurries separately, and use ultrasonic spraying process to prepare anodic and cathode catalyst layers on both sides of the proton exchange membrane prepared in step S3. S5. After aligning the layers prepared in the above steps using a mechanical positioning structure, stack them together, encapsulate them by hot pressing and sintering the encapsulation frame, assemble the electrical interface and fluid interface in accordance with the interface structure position, and finally integrate the photovoltaic direct drive power module and sensor module to complete the chip fabrication.

8. The method for preparing a photovoltaic-coupled electrolytic hydrogen production chip as described in claim 7, characterized in that: In step S1, the green blank is placed in a graphite crucible and heated to 1300℃-1400℃ at a heating rate of 2-4℃ / min under argon atmosphere protection. It is then sintered at a constant temperature for 3-5 hours and cooled to room temperature with the furnace at a rate of 1.5-2.5℃ / min to obtain a Ti3AlC2MAX phase ceramic matrix. When depositing a gradient composite layer of nanodiamond using the MPCVD process, the diamond content gradually increases from 0% to 100% starting from the surface of the Ti3AlC2MAX phase ceramic matrix by adjusting the methane / hydrogen flow ratio from 0% to 5% to 10% to 15%.

9. The method for preparing a photovoltaic-coupled electrolytic hydrogen production chip as described in claim 7, characterized in that, In step S4, a three-step ultrasonic spraying process is adopted: the first layer of slurry has a solid content of 3%, the spraying temperature is 130℃, and the solution flow rate is 0.7mL / min; the second layer of slurry has a solid content of 5%, the spraying temperature is 140℃, and the solution flow rate is 1.1mL / min; the third layer of slurry has a solid content of 8%, the spraying temperature is 150℃, and the solution flow rate is 1.5mL / min.

10. A photovoltaic-coupled electrolysis hydrogen production chip stacking module, characterized in that: The photovoltaic-coupled electrolytic hydrogen production chip as described in any one of claims 1-6 is tightly stacked by means of a mechanical positioning structure and connectors, and is connected in parallel to electrical and fluid inlet and outlet components through electrical and fluid interfaces.

Images