CN-122025666-A - Multi-scale gradient coupling proton exchange membrane fuel cell catalytic layer water retaining structure and preparation method thereof

CN122025666ACN 122025666 ACN122025666 ACN 122025666ACN-122025666-A

Abstract

The present invention belongs to the field of proton exchange membrane fuel cells, especially a multi-scale gradient coupled proton exchange membrane fuel cell catalytic layer water retention structure and preparation method. In response to the existing hydrophilic and hydrophobic regulation, which is mostly chemical component adjustment and lacks synergistic design with physical pore structure, water retention materials are mostly static hydrophilic substances that cannot dynamically respond to humidity changes. The preparation method often uses spraying or coating, which makes it difficult to achieve precise control of materials and structures, resulting in insufficient performance stability of fuel cells under wide temperature range and variable humidity conditions. The present invention includes a proton exchange membrane and a gas diffusion layer. The proton exchange membrane is sequentially stacked in the direction of the gas diffusion layer with a water retention core layer, a transition regulation layer, and a drainage buffer layer. The synergistic regulation of chemical components and physical structures, Realize dynamic equilibrium management of water in the catalytic layer.

Inventors

WANG SHANGSHANG
WANG XIAOXING

Assignees

常州氢龙科技有限公司

Dates

Publication Date: 20260512
Application Date: 20251224

Claims (10)

1. The water-retaining structure of the catalytic layer of the proton exchange membrane fuel cell is characterized by comprising a proton exchange membrane (1) and a gas diffusion layer (5), wherein the proton exchange membrane (1) is sequentially provided with a water-retaining core layer (2), a transition regulating layer (3) and a drainage buffer layer (4) in a laminated manner towards the gas diffusion layer (5); The water-retaining core layer (2) adopts a design with high hydrophilic component and low porosity, the drainage buffer layer (4) adopts a design with high hydrophobic component and high porosity, and the transition regulating layer (3) is used for realizing smooth transition of hydrophilic-hydrophobic characteristic and porosity from the water-retaining core layer (2) to the drainage buffer layer (4); the water-retaining core layer (2), the transition regulating layer (3) and the drainage buffer layer (4) are respectively dispersed with a responsive core-shell nano-carrier, the responsive core-shell nano-carrier takes a porous Fe-N-C material as an inner core and takes a humidity-sensitive metal organic framework material as an outer shell.
2. The multi-scale gradient coupled proton exchange membrane fuel cell catalytic layer water retaining structure according to claim 1, wherein hollow SiO 2 nanospheres are additionally added in the water retaining core layer (2).
3. The multi-scale gradient-coupled proton exchange membrane fuel cell catalyst layer water retention structure of claim 1, wherein the moisture sensitive metal organic framework material is Co-MOF-74.
4. The multi-scale gradient coupled proton exchange membrane fuel cell catalytic layer water retention structure according to claim 1, wherein the thickness of the water retention core layer (2), the transition regulating layer (3) and the drainage buffer layer (4) is 10 μm, the porosity of the water retention core layer is 20%, the porosity of the transition regulating layer is 32%, and the porosity of the drainage buffer layer is 42%.
5. A method for preparing the water retention structure of the catalytic layer of the proton exchange membrane fuel cell as claimed in any one of claims 1 to 3, comprising the steps of: s1, preparing a response type core-shell nano-carrier, namely dispersing a porous Fe-N-C material in a methanol solution containing a cobalt source and an organic ligand, and performing solvothermal reaction, centrifugal washing and drying to obtain the Co-MOF-74 coated core-shell nano-carrier; S2, preparing three-layer catalytic slurry: S2.1, preparing slurry of a water-retaining core layer (2), namely dispersing a Pt/C catalyst, the core-shell nano-carrier prepared in the step S1, hollow SiO 2 nano-spheres and low-equivalent perfluorinated sulfonic acid resin in a mixed solvent of water and alcohol, and performing ultrasonic dispersion to form uniform slurry; S2.2, preparing slurry of a transition regulating layer (3), namely dispersing the Pt/C catalyst, the core-shell nano-carrier prepared in the step S1, low-equivalent perfluorinated sulfonic acid resin and high-equivalent perfluorinated sulfonic acid resin in a mixed solvent of water and alcohol, and performing ultrasonic dispersion to form uniform slurry; S2.3, preparing slurry of a drainage buffer layer (4), namely dispersing the Pt/C catalyst, the core-shell nano-carrier prepared in the step S1, and a compound of high-equivalent perfluorinated sulfonic acid resin and polytetrafluoroethylene in a mixed solvent of water and alcohol, and performing ultrasonic dispersion to form uniform slurry; S3, sequentially printing the three-layer structure on the surface of the pretreated proton exchange membrane by adopting a microfluidic ink-jet 3D printing technology, and then carrying out hot pressing treatment to be compounded with the gas diffusion layer.
6. The method for preparing the water-retaining structure of the catalytic layer of the multi-scale gradient coupled proton exchange membrane fuel cell according to claim 1, wherein in the step S1, the pore volume of the porous Fe-N-C material is 0.105cm 3 /g, the cobalt source is cobalt nitrate, the organic ligand is 2-methylimidazole, the solvothermal reaction condition is 150 ℃ for 8 hours, and the thickness of MOFs shells of the prepared core-shell nano-carrier is about 50nm.
7. The method for preparing the water-retaining structure of the catalytic layer of the multi-scale gradient coupled proton exchange membrane fuel cell according to claim 1, wherein in the step S2.1, the equivalent of the low-equivalent perfluorinated sulfonic acid resin is 750, and the diameter of the hollow SiO 2 nanospheres is 200nm. In step S2.2, the equivalent weight of the low equivalent weight perfluorosulfonic acid resin is 750, and the equivalent weight of the Gao Dangliang perfluorosulfonic acid resin is 1100. In step S2.3, the compound consists of perfluorinated sulfonic acid resin with the equivalent weight of 1100 and polytetrafluoroethylene, wherein the mass ratio of the polytetrafluoroethylene is 15%.
8. The method for preparing a water-retaining structure of a catalytic layer of a multi-scale gradient coupled proton exchange membrane fuel cell according to claim 1, wherein in step S2, the mixed solvent of water and alcohol is a solvent in which water and isopropanol, ethanol or n-propanol are mixed according to a volume ratio of 1:4.
9. The preparation method of the multi-scale gradient coupling proton exchange membrane fuel cell catalytic layer water retention structure is characterized in that in the step S3, the diameter of a nozzle for microfluidic ink-jet 3D printing is 75 mu m, a dense lattice pattern is adopted when a water retention core layer (2) is printed, the printing speed is 5mm/S, a gradual change pattern is adopted when a transition regulating layer (3) is printed, the printing speed is 7mm/S, a grid pattern is adopted when a drainage buffer layer (4) is printed, and the printing speed is 10mm/S.
10. The method for preparing the water-retaining structure of the catalytic layer of the multi-scale gradient coupled proton exchange membrane fuel cell according to claim 1, wherein in the step S3, the condition of the hot pressing treatment is that the temperature is 130 ℃, the pressure is 6MPa, and the time is 3 minutes.

Description

Multi-scale gradient coupling proton exchange membrane fuel cell catalytic layer water retaining structure and preparation method thereof Technical Field The invention relates to the technical field of proton exchange membrane fuel cells, in particular to a multi-scale gradient coupling water-retaining structure of a catalytic layer of a proton exchange membrane fuel cell and a preparation method. Background Proton Exchange Membrane Fuel Cells (PEMFCs) function as efficient and clean energy conversion devices, whose performance is highly dependent on the level of water management within the catalytic layer. The Catalytic Layer (CL) needs to maintain proper humidity to ensure proton conduction, and at the same time, needs to drain the reaction generated water in time to avoid flooding, and this contradictory requirement puts severe demands on the structural design of the catalytic layer. In the prior art, chinese patent CN200910248843.2 discloses that the water retention of the catalytic layer is improved by adding nitrogen and titanium dioxide modified by metal oxide, but only by single material modification, and no structural gradient design is involved. CN120505647a patent published by university of company proposes a hydrophilic-hydrophobic gradient catalytic layer, which forms a three-layer structure by perfluorosulfonic acid resins of different EW values, but does not incorporate physical structure regulation of porous materials. Patent CN110380060B of Jiangsu dry Jing Xin energy adopts covalent organic framework materials to realize self-humidification, but the material distribution lacks gradient design, and is difficult to cope with dynamic working condition changes. The prior art has the following defects that (1) hydrophilic and hydrophobic regulation is mostly chemical component regulation and is lack of cooperative design with a physical pore structure, (2) a water-retaining material is mostly a static hydrophilic substance and cannot dynamically respond to humidity change, and (3) the preparation method is mostly spray-coated or coated, so that accurate regulation of the material and the structure is difficult to realize. These defects result in insufficient performance stability of the fuel cell over a wide temperature range and variable humidity operating conditions. Therefore, a water-retaining structure of a catalytic layer of a multi-scale gradient coupled proton exchange membrane fuel cell and a preparation method thereof are needed to solve the above-mentioned problems. Disclosure of Invention According to the multi-scale gradient coupling proton exchange membrane fuel cell catalytic layer water-retaining structure and the preparation method, dynamic balance management of water in the catalytic layer is achieved through cooperative regulation and control of chemical components and physical structures. In order to achieve the above purpose, the present invention adopts the following technical scheme: The water-retaining structure of the multi-scale gradient coupled proton exchange membrane fuel cell catalytic layer comprises a proton exchange membrane and a gas diffusion layer, wherein the proton exchange membrane is sequentially provided with a water-retaining core layer, a transition regulation layer and a drainage buffer layer in a laminated manner towards the gas diffusion layer; The water-retaining core layer adopts a design with high hydrophilic component and low porosity, the drainage buffer layer adopts a design with high hydrophobic component and high porosity, and the transition regulating layer is used for realizing smooth transition of hydrophilic-hydrophobic characteristic and porosity from the water-retaining core layer to the drainage buffer layer; the water-retaining core layer, the transition regulating layer and the drainage buffer layer are all dispersed with a response type core-shell nano-carrier, wherein the response type core-shell nano-carrier takes a porous Fe-N-C material as an inner core and a humidity sensitive metal-organic framework material as an outer shell. Preferably, hollow SiO 2 nanospheres are additionally added in the water-retaining core layer. Preferably, the humidity sensitive metal organic framework material is Co-MOF-74. Preferably, the thicknesses of the water-retaining core layer, the transition regulating layer and the drainage buffer layer are 10 mu m respectively, the porosity of the water-retaining core layer is 20%, the porosity of the transition regulating layer is 32%, and the porosity of the drainage buffer layer is 42%. The preparation method of the water-retaining structure of the catalytic layer of the proton exchange membrane fuel cell comprises the following steps: s1, preparing a response type core-shell nano-carrier, namely dispersing a porous Fe-N-C material in a methanol solution containing a cobalt source and an organic ligand, and performing solvothermal reaction, centrifugal washing and drying to obtain the Co-MOF-74 coated