Integrated renewable fuel cell oxygen electrode amphipathic high-conductivity titanium-based porous transmission layer as well as preparation method and application of integrated renewable fuel cell oxygen electrode amphipathic high-conductivity titanium-based porous transmission layer
By employing an amphiphilic, highly conductive titanium-based porous transport layer on the oxygen electrode side, the problems of easy corrosion and flooding of porous transport layers in URFCs were solved, achieving efficient water management in water electrolysis and fuel cell modes, and improving the overall performance and efficiency of URFCs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2026-03-10
AI Technical Summary
The existing porous transport layer on the oxygen electrode side is prone to corrosion and flooding in integrated regenerative fuel cells, affecting its efficiency and stability in water electrolysis and fuel cell modes.
A highly conductive titanium-based porous transport layer is prepared by using a surface-modified titanium-based porous material with alternating hydrophilic and hydrophobic regions. The hydrophobic region accounts for 10% to 90% of the effective surface area. The hydrophobic polymer is coated by printing, coating, spraying or other methods, and then subjected to high-temperature heating or ultraviolet crosslinking treatment.
It achieves efficient water transport in water electrolysis mode and rapid drainage in fuel cell mode, improves the conductivity of oxygen electrode and the overall performance of URFC, and enhances cycle efficiency and stability.
Smart Images
Figure CN121642008A_ABST
Abstract
Description
Technical fields:
[0001] This invention relates to the field of integrated renewable fuel cell technology, specifically to an amphiphilic, highly conductive titanium-based porous transport layer for an oxygen electrode in an integrated renewable fuel cell, its preparation method, and its application. Background technology:
[0002] Integrated Regenerative Fuel Cells (URFCs) combine fuel cells (FCs) with water electrolysis (WE) technology. The fuel cell produces water using H2 fuel and O2 oxidant, and water electrolysis generates the necessary H2 fuel and O2 oxidant for fuel cell operation, thus "regenerating" the fuel cell through water electrolysis. URFCs combine the advantages of both fuel cells and water electrolysis, featuring a compact system, low-temperature start-up, and green, pollution-free operation. Furthermore, URFCs have a theoretical specific energy density of 3.7 kWh / kg and a packaged specific energy density (including the H2 / O2 tank) of 0.4–1 kWh / kg, offering significant advantages in high-energy-density storage and conversion.
[0003] The porous transport layer (PTL), a crucial component of URFC, plays a vital role in transporting gas and liquid two-phase fluids. While ordinary carbon paper is generally sufficient for the hydrogen electrode side, the PTL for the oxygen electrode needs to effectively fulfill its conflicting roles in both fuel cell and water electrolysis modes. In fuel cell mode, the oxygen reduction reaction (ORR) requires a hydrophobic PTL for efficient drainage and gas-phase reaction; in water electrolysis mode, the oxygen evolution reaction (OER) requires a hydrophilic PTL, which is more suitable for transporting aqueous reactants to the catalyst layer for water separation. Furthermore, the high temperature, high humidity, and acidic environment of water electrolysis mode places higher demands on PTL stability. Commonly used polytetrafluoroethylene-modified carbon materials (such as carbon black) are highly effective at drainage in fuel cell mode, but they are highly susceptible to corrosion in water electrolysis mode, especially since current oxygen electrodes contain Pt components, further reducing the decomposition voltage to 0.118V. Even with anti-corrosion treatment, electrochemical degradation and flow imbalances still occur, limiting the rate and efficiency of the oxygen electrode reaction. Corrosion-resistant porous titanium-based materials (such as titanium mesh, titanium felt, and titanium sheets) have good hydrophilicity and exhibit significant water transport efficiency in water electrolysis mode. However, they face drainage difficulties in fuel cell mode, easily leading to "flooding." Therefore, high-efficiency corrosion-resistant PTLs are one of the key technologies affecting the power generation performance and conversion efficiency of URFCs. Summary of the Invention:
[0004] The purpose of this invention is to provide an amphiphilic, highly conductive titanium-based porous transport layer for an integrated regenerative fuel cell oxygen electrode, along with its preparation method and application. This invention solves the problems of easy corrosion of the porous transport layer (PTL) on the oxygen electrode side in the URFC water electrolysis mode and easy flooding in the fuel cell mode.
[0005] This invention is achieved through the following technical solutions:
[0006] An integrated regenerative fuel cell oxygen electrode features an amphiphilic, highly conductive titanium-based porous transport layer. The substrate is a surface-modified highly conductive titanium-based porous material with alternating hydrophilic and hydrophobic regions. The hydrophilic regions are the surface-modified highly conductive titanium-based porous material itself, while the hydrophobic regions are composed of hydrophobic polymer materials. The hydrophobic regions are orderly and spaced on the hydrophilic titanium-based porous material, and the total geometric area of the hydrophobic regions accounts for 10% to 90% of the effective surface area of the porous transport layer.
[0007] Preferably, the highly conductive titanium-based porous material is a titanium mesh, titanium felt, titanium sheet, or the like, and the hydrophobic polymer material is polytetrafluoroethylene, polystyrene, polydimethylsiloxane, or the like.
[0008] Preferably, the total geometric area of the hydrophobic region accounts for 50% of the effective surface area of the porous transport layer.
[0009] The hydrophobic and hydrophilic regions are distributed alternately in one or more of the following ways: striped, lattice-shaped, or radial. Preferably, the hydrophobic and hydrophilic regions are distributed alternately in striped patterns.
[0010] When it is a lattice, the hydrophobic region can be in the shape of a triangle, square, trapezoid, polygon, star, etc.
[0011] The method for preparing the amphiphilic, highly conductive titanium-based porous transport layer includes the following steps:
[0012] (1) Cut the highly conductive titanium-based porous material to the appropriate size according to the area of the URFC membrane electrode, clean it ultrasonically in NaOH solution to remove impurities such as grease, then clean it with deionized water and dry it in a vacuum oven.
[0013] (2) The titanium-based porous material obtained in step (1) is calcined at a high temperature of 500-1000℃ in an ammonia atmosphere to obtain a surface-modified high-conductivity titanium-based porous material.
[0014] (3) Dissolve the hydrophobic polymer in a selective solvent to prepare a 2-10 wt% hydrophobic polymer solution. Coat the surface of the highly conductive titanium-based porous material with surface modification treatment obtained in step (2) with the hydrophilic and hydrophobic regions alternately distributed. Allow it to air dry naturally for 12 hours.
[0015] (4) The template coated with hydrophobic material obtained in step (3) is subjected to crosslinking treatment.
[0016] Preferably, the concentration of the NaOH solution in step (1) is 1M, and the ultrasonic cleaning time is 1h.
[0017] Preferably, the calcination temperature in step (2) is 800°C.
[0018] Preferably, in step (3), the hydrophilic and hydrophobic regions are alternately distributed using a mask, and the hydrophobic polymer solution is coated using one or more of the following methods: printing, coating, spraying, deposition, sputtering; the hydrophilic and hydrophobic regions are alternately distributed using one or more of the following methods: strip, dot matrix, radial, etc.
[0019] Preferably, in step (3), the hydrophobic polymer is polystyrene, the selective solvent is toluene, and the polystyrene concentration is 5 wt%; the mask is a strip-shaped spacer structure; and the coating method is spray gun spraying.
[0020] Step (4) crosslinking treatment includes one or more of the following: high temperature heating, ultraviolet irradiation, plasma treatment, etc. Preferably, the crosslinking treatment method in step (4) is ultraviolet irradiation.
[0021] The present invention also protects the application of the amphiphilic high conductivity titanium-based porous transport layer on the oxygen electrode side in an integrated renewable fuel cell (URFC), wherein the amphiphilic high conductivity titanium-based porous transport layer is used alone or in combination of multiple layers.
[0022] The beneficial effects of this invention are as follows:
[0023] (1) In this invention, surface modification of titanium-based porous materials can effectively improve the electrical conductivity of titanium oxide, thereby improving the conductivity of the porous transport layer (PTL) on the oxygen electrode side and the overall performance of the integrated renewable fuel cell (URFC).
[0024] (2) The hydrophilic and hydrophobic regions are distributed alternately on the surface of the porous titanium material to achieve a balance between oxygen electrode PTL water transport in fuel cell and water electrolysis functions. While maintaining the water transport efficiency in the water electrolysis mode, it effectively improves the rapid removal of water in the fuel cell mode, thereby improving the overall cycle efficiency of URFC and overcoming the problems of easy corrosion of the existing porous transport layer (PTL) on the oxygen electrode side in the URFC water electrolysis mode and easy flooding in the fuel cell mode.
[0025] (3) The hydrophilic and hydrophobic region spacing control method in this invention is simple and easy to operate, which is conducive to technology scale-up and reduces the cost of commercial URFC.
[0026] In summary, this invention uses an amphiphilic, highly conductive titanium-based porous transport layer as the oxygen electrode of URFC, which can improve the electrical transfer efficiency of URFC, solve the contradiction in water transport under the two modes of URFC, and thus improve the overall efficiency of URFC. Attached image description:
[0027] Figure 1This is a schematic diagram of the lattice-distributed amphiphilic highly conductive titanium-based porous transport layer prepared in Example 1. Hydrophobic regions are orderly distributed on the surface of the hydrophilic titanium-based porous material. The proportion of hydrophobic regions can be controlled by adjusting the area of the hydrophobic regions as needed.
[0028] Figure 2 The image shows the strip-shaped, spaced, amphiphilic, highly conductive titanium-based porous transport layer prepared in Example 2; where A is a schematic diagram and B is a finished product image.
[0029] Figure 3 The porous transport layers obtained in Example 2 and Comparative Example 1 were tested in URFC fuel cells and water electrolysis modes. As can be seen from the figures, the amphiphilic, highly conductive titanium-based porous transport layer obtained in Example 2 significantly improves the performance of the URFC, achieving a performance of 0.5 A / cm². 2 At the current density, the fuel cell voltage reaches 0.64V, which is much higher than the 0.46V of ordinary titanium sheets. Detailed implementation method:
[0030] The following is a further description of the invention, but not a limitation thereof.
[0031] Due to the limited range of processing sizes, coating equipment can often only process workpieces with limited width. In this regard, the present invention can prepare large-size porous transport layers by splicing small-size porous transport layers using common welding processes such as arc welding, gas welding, and laser welding, or by using processes such as adhesive bonding; during splicing, it can be splicing porous transport layers with a single characteristic interval distribution of hydrophobic regions, or it can be splicing porous transport layers with multiple characteristic interval distributions.
[0032] Example 1: A porous transport layer based on amphiphilic high conductivity titanium with an ordered dot matrix distribution was prepared by printing.
[0033] Figure 1 This is a schematic diagram of the amphiphilic, highly conductive titanium-based porous transport layer with ordered lattice distribution characteristics in this invention. In the diagram, x and y represent the length and width of the effective region of the transport layer, respectively; a and b represent the length and width of the hydrophobic region, respectively; and c and d represent the longitudinal and transverse spacing distances of the hydrophobic region, respectively. The values of a, b, c, and d can be flexibly adjusted to meet the requirements of practical applications based on the proportion of the hydrophobic region to the effective region of the transport layer.
[0034] It should be noted that, due to the diversity of lattice structures, the hydrophobic region can be constructed into shapes such as triangles, squares, trapezoids, polygons, and stars, all of which are considered variations or improvements of the lattice structure and are within the scope of protection of this invention.
[0035] Example 2: An amphiphilic, highly conductive titanium-based porous transport layer with strip-shaped spacing of hydrophilic and hydrophobic regions was prepared on a titanium sheet by spraying.
[0036] First, titanium sheets with a thickness of 200 micrometers were cut into 2.5×2.5 squares, degreased in 1M NaOH solution, ultrasonically cleaned, rinsed with deionized water, vacuum dried, and placed in a tube furnace. Ammonia gas was then introduced, and the sheets were calcined at 800℃ for 12 hours to obtain surface-modified high-conductivity titanium sheets. 1g of polystyrene was dissolved in 20g of toluene to form a 5wt% toluene solution. Under a strip mask, the polystyrene solution was sprayed onto the calcined surface-modified high-conductivity titanium sheets using a spray gun. The sheets were then air-dried in a fume hood for 12 hours and then irradiated under a UV lamp for 4 hours to perform polystyrene crosslinking. Figure 2 Figure A is a schematic diagram of the amphiphilic, highly conductive titanium-based porous transport layer with a strip-shaped regional distribution characteristic in this invention. Here, x and y represent the length and width of the effective region of the transport layer, respectively, and a and b are the widths of the hydrophilic and hydrophobic regions, respectively. Based on the proportion of the hydrophobic region to the effective region of the transport layer, the values of a and b can be flexibly adjusted to meet the requirements of practical applications. Figure 2 Image B shows the finished product of the highly conductive titanium-based porous transport layer with strip-shaped spacing of hydrophilic / hydrophobic regions prepared in this embodiment. The hydrophobic regions account for approximately 50% of the effective area of the porous transport layer.
[0037] Secondly, the amphiphilic, highly conductive titanium-based porous transport layer obtained in this embodiment was used in the assembly of a URFC, and the IV polarization curves were tested in fuel cell and water electrolysis modes. The test conditions were: temperature 80℃, 1 atm, hydrogen electrode catalyst was Pt / C, and the porous transport layer was carbon paper; the oxygen electrode catalyst was Pt / IrO2 with a weight ratio of 3:1. The amphiphilic, highly conductive titanium-based porous transport layer with strip-shaped spacing of hydrophilic / hydrophobic regions obtained in this embodiment was used, denoted as Am-Ti-PTL. The results are as follows... Figure 3 As shown.
[0038] Comparative Example 1:
[0039] Using the same conditions as in Example 2, except that the porous transport layer on the oxygen electrode side is made of ordinary titanium sheet, denoted as (Ti-PTL), the resulting IV polarization curve is shown below. Figure 3 As shown, the amphiphilic, highly conductive titanium-based porous transport layer obtained in Example 2 significantly improves the performance of URFC, achieving a performance increase of 0.5 A / cm². 2 At the specified current density, the fuel cell voltage reaches 0.64V, significantly higher than the 0.46V of ordinary titanium sheets. In fuel cell mode, ordinary titanium sheets are prone to flooding, resulting in extremely poor fuel cell performance, with a cycle efficiency of only 25.3% at 0.5A / cm². 2 (0.46 / 1.82); while the amphiphilic, highly conductive titanium-based porous transport layer of this invention has little effect on water electrolysis performance, it significantly improves fuel cell performance, increasing cycle efficiency to 34.2% @ 0.5 A / cm. 2(0.64 / 1.87). This demonstrates that the present invention effectively improves the rapid removal of water in the fuel cell mode while maintaining the water transport efficiency in the water electrolysis mode.
[0040] Finally, it should be noted that the above are merely preferred embodiments of the present invention. Those skilled in the art can still modify the technical solutions described in the foregoing embodiments, make equivalent substitutions for some technical features, or improve some operational steps. Any modifications, substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. An integral regenerative fuel cell oxygen electrode amphiphilic high conductive titanium-based porous transport layer characterized by, The base is a high-conductivity titanium-based porous material with surface modification treatment, and the hydrophilic and hydrophobic regions are distributed in intervals; the hydrophilic region is the high-conductivity titanium-based porous material with surface modification treatment itself, and the hydrophobic region is composed of a hydrophobic polymer material, and the hydrophobic regions are orderly and interval-distributed on the hydrophilic titanium-based porous material, and the total geometric area of the hydrophobic regions accounts for 10% to 90% of the effective surface area of the porous transmission layer.
2. The amphiphilic highly conductive titanium-based porous transport layer of claim 1, wherein, The high-conductivity titanium-based porous material is one of a titanium mesh, a titanium felt and a titanium sheet, and the hydrophobic polymer material is one of polytetrafluoroethylene, polystyrene and polydimethylsiloxane; the total geometric area of the hydrophobic regions accounts for 50% of the effective surface area of the porous transmission layer.
3. The amphiphilic, highly conductive, titanium-based, porous transport layer of claim 1, wherein, The interval distribution of the hydrophobic and hydrophilic regions adopts one or more of the following: a strip shape, a dot matrix and a radial shape.
4. The method of claim 1, wherein the preparation of the amphiphilic high- conductive titanium-based porous transport layer is characterized by, The method comprises the following steps: (1) The high-conductivity titanium-based porous material is cut into a corresponding size according to the size of the URFC membrane electrode area, ultrasonic cleaned in a NaOH solution, then cleaned with deionized water, and dried in a vacuum oven; (2) The titanium-based porous material obtained in step (1) is calcined at a high temperature of 500 to 1000 ℃ in an ammonia atmosphere to obtain a high-conductivity titanium-based porous material with surface modification treatment; (3) The hydrophobic polymer is dissolved in a selective solvent to prepare a 2 to 10 wt% hydrophobic polymer solution, the hydrophobic polymer solution is coated on the surface of the high-conductivity titanium-based porous material with surface modification treatment obtained in step (2) to make the hydrophilic and hydrophobic regions interval-distributed, and the interval-distributed hydrophilic and hydrophobic regions are naturally dried in air for 12 h; (4) The template coated with the hydrophobic material obtained in step (3) is subjected to cross-linking treatment.
5. The method of claim 4, wherein the method further comprises the step of: The concentration of the NaOH solution in step (1) is 1 M, and the ultrasonic cleaning time is 1 h.
6. The method of claim 4, wherein the amphiphilic high conductive titanium-based porous transport layer is prepared by the steps of: The calcination temperature in step (2) is 800 ℃.
7. The method of claim 4, wherein the method further comprises the step of: In step (3), the interval distribution of the hydrophilic and hydrophobic regions is controlled by a mask plate, the coating of the hydrophobic polymer solution adopts one or more of the following methods: printing, coating, spraying, deposition and sputtering, and the interval distribution of the hydrophilic and hydrophobic regions adopts one or more of the following: a strip shape, a dot matrix and a radial shape.
8. The method of claim 4, wherein the amphiphilic high conductive titanium-based porous transport layer is prepared by the steps of: In step (3), the hydrophobic polymer is polystyrene, the selective solvent is toluene, the concentration of the polystyrene is 5 wt%, the mask plate is a strip interval structure, and the coating method is spray gun spraying.
9. The method of claim 4, wherein the method further comprises the step of: The cross-linking treatment in step (4) comprises one or more of the following: high-temperature heating, ultraviolet irradiation and plasma treatment.
10. Use of the amphiphilic highly conductive titanium-based porous transport layer of claim 1 on the oxygen electrode side of an integrated regenerative fuel cell, characterized in that, The amphiphilic high-conductivity titanium-based porous transmission layer is used alone or in combination with multiple layers.