CN-122000375-A - Gas diffusion layer and preparation method and application thereof

CN122000375ACN 122000375 ACN122000375 ACN 122000375ACN-122000375-A

Abstract

The application relates to the technical field of fuel cells, and provides a gas diffusion layer, a preparation method and application thereof. The gas diffusion layer comprises a substrate layer and a microporous layer attached to one side surface of the substrate layer, wherein the substrate layer is provided with stacked carbon fibers, pores of the substrate layer are formed among the carbon fibers, the microporous layer comprises stacked conductive particles, at least part of the conductive particles penetrate into the substrate layer, the microporous layer comprises first pores and second pores, the pore diameter of the first pores is R1, R1 is less than or equal to 5 mu m and less than or equal to 10 mu m, the pore diameter of the second pores is R2, R2 is less than or equal to 1 mu m and less than 5 mu m, and the pore area ratio of the first pores is 25% -35%. The gas diffusion layer effectively improves the air permeability while improving the performance through the synergistic effect of the pores with the pore size and the multilevel distribution, so that the gas diffusion layer has good drainage performance and air permeability.

Inventors

JIA JIANDONG
YANG YINJING
LI NANXING
ZHOU HAO
KONG ZHIQI

Assignees

杭州科百特过滤器材有限公司

Dates

Publication Date: 20260508
Application Date: 20251231

Claims (13)

1. A gas diffusion layer comprising a substrate layer and a microporous layer attached to a side surface of the substrate layer, the substrate layer having stacked carbon fibers with substrate layer pores formed therebetween, wherein the microporous layer comprises stacked conductive particles, at least a portion of the conductive particles penetrating into the substrate layer, the microporous layer comprising first pores and second pores; The aperture of the first pore is R1, R1 is less than or equal to 5 μm and less than or equal to 10 μm, the aperture of the second pore is R2, R2 is less than or equal to 1 μm and less than 5 μm, and the pore area ratio of the first pore is 25% -35%.
2. A gas diffusion layer according to claim 1, wherein the second pores have a pore area ratio of 5% to 15%, and/or The microporous layer further comprises a third pore, the pore diameter of the third pore is smaller than that of the second pore, and the average pore diameter of the microporous layer is 0.1-1.5 mu m.
3. The gas diffusion layer of claim 1, wherein the microporous layer comprises through voids, wherein the through voids extend through the microporous layer and communicate with the substrate layer voids, and/or At least a portion of the carbon fibers extend into the microporous layer.
4. The gas diffusion layer of claim 3, wherein the sidewall of the through-pores comprises the carbon fibers extending to the microporous layer.
5. A gas diffusion layer according to any one of claims 1 to 4, wherein the maximum pore diameter in the through pores is d1, the minimum pore diameter is d2, the ratio of d1 to d2 is 1 to 2, and/or The roughness of the base layer is a, which satisfies at least one of the following (1) to (3); (1) The A and d1 are positively correlated; (2) The relation between A and d1/d2 is A (d 1/d 2) =10-20 mu m; (3) The A is 10-20 mu m.
6. The gas diffusion layer according to any one of claims 1 to 4, wherein the gas diffusion layer satisfies at least one of the following (1) to (4): (1) The compression ratio of the gas diffusion layer under 1MPa is 10% -30%; (2) The thickness of the gas diffusion layer is 150-350 mu m; (3) The resistivity of the gas diffusion layer is 400-500 mΩ cm; (4) The tensile strength of the gas diffusion layer is 10-15 MPa.
7. The method of manufacturing a gas diffusion layer according to any one of claims 1 to 6, comprising the steps of: The microporous layer slurry is arranged on one side surface of the substrate layer to obtain a gas diffusion layer precursor; Sintering the precursor of the gas diffusion layer to obtain the gas diffusion layer; wherein the substrate layer is provided with stacked carbon fibers, and substrate layer pores are formed among the carbon fibers; The microporous layer slurry comprises conductive particles, a hydrophobic agent and a pore-forming agent, wherein the pore-forming agent comprises ammonium salt and carbonate, and the mass ratio of the ammonium salt to the carbonate is (0.1-1) to 1; the sintering treatment comprises a first sintering treatment and a second sintering treatment, wherein the temperature of the first sintering treatment is 250-320 ℃, and the temperature of the second sintering treatment is 350-400 ℃.
8. The method of manufacturing of claim 7, wherein the microporous layer slurry satisfies at least one of the following (1) to (5): (1) The mass ratio of the conductive particles to the pore-forming agent is (10-20): 3-6; (2) The content of the conductive particles is 10% -20%; (3) The particle size of the conductive particles is 30-100 nm; (4) The conductive particles include carbon particles; (5) The content of the pore-forming agent is 3% -6%.
9. The method according to claim 7 or 8, wherein the content of the hydrophobizing agent is 5% -10%, and/or The hydrophobizing agent comprises at least one of polytetrafluoroethylene and polydifluoroethylene.
10. The method of making of claim 7 or 8, wherein the microporous layer slurry further comprises a dispersant, and the dispersant satisfies at least one of the following (1) to (2): (1) The content of the dispersing agent is 1% -6%; (2) The dispersing agent comprises at least one of cellulose ether, triton X-100, PVP and SDS.
11. The method of claim 7 or 8, wherein the microporous layer slurry further comprises at least one of a thickener, a leveling agent, and a defoaming agent, and the contents of the thickener, the leveling agent, and the defoaming agent are respectively: 1% -2% of a thickening agent; 1% -3% of a leveling agent; 1% -3% of a defoaming agent.
12. The method according to claim 7 or 8, wherein the first sintering treatment is performed for 1 to 5 minutes, and/or The second sintering treatment time is 10-30 min, and/or The temperature rising rate of the sintering treatment is 3-9 ℃ per minute.
13. A proton exchange membrane fuel cell comprising a gas diffusion layer according to any one of claims 1 to 6 or a gas diffusion layer produced by the production method according to any one of claims 8 to 12.

Description

Gas diffusion layer and preparation method and application thereof Technical Field The application belongs to the technical field of fuel cells, and particularly relates to a gas diffusion layer, a preparation method and application thereof. Background Proton exchange membrane fuel cells (Proton Exchange Membrane Fuel Cell, PEMFCs) are devices that convert energy released by the reaction of clean energy hydrogen and oxygen to produce water into electrical energy. The core monomer structure of the membrane consists of a proton exchange membrane (Proton Exchange Membrane, PEM), a catalytic layer (CATALYST LAYER, CL) which is symmetrically arranged on two sides, a gas diffusion layer (Gas Diffusion Layer, GDL) and a Bipolar Plate (BP). The gas diffusion layer is used as a key mass transfer component and plays roles of gas transmission and liquid water management. The porous structure can convey the reaction gases (hydrogen and oxygen) from the bipolar plate flow channels to the reaction interface of the catalytic layer, and simultaneously discharge the water generated by the electrochemical reaction to the bipolar plate. Specifically, when the proton exchange membrane fuel cell is in operation, oxygen (or air) reaches the cathode catalytic layer through the gas diffusion layer to form oxygen ions under the action of the cathode catalyst, and hydrogen reaches the anode catalytic layer through the gas diffusion layer to lose electrons to become protons under the action of the anode catalyst (H +). Electrons flow through an external circuit to the cathode, creating an electric current, while protons (H +) are specifically transported across the proton exchange membrane to the cathode and react with oxygen ions to produce water molecules, which are expelled through the gas diffusion layer. In order to better improve the performance of the proton exchange membrane, the gas diffusion layer needs to have good air permeability so as to ensure that enough hydrogen and oxygen enter the catalytic layer to react, and meanwhile, the gas diffusion layer needs to have good drainage performance so that generated water can be discharged in time, and the performance of the proton exchange membrane fuel cell is prevented from being reduced due to flooding. The gas diffusion layer is typically composed of a base layer (Macro-porous Substrate, MPS) and a microporous layer (Micro-porous Layer, MPL), wherein the microporous layer is in direct contact with the catalytic layer. The gas enters the catalytic layer from the microporous layer, while the water produced by the catalytic layer first enters the microporous layer. Therefore, the drainage performance and air permeability in the gas diffusion layer are mainly dependent on the microporous layer. However, in the prior art, the air permeability of the microporous layer is difficult to be ensured while the microporous layer has good drainage properties, and the drainage properties are reduced when the air permeability of the microporous layer is improved. For example, in the prior art, drainage of the microporous layer mainly depends on the hydrophobic gradient inside the microporous layer and between the microporous layer and the substrate layer, the preparation process of the scheme is complex, accurate control is difficult, and excessive hydrophobic agent easily causes pore blocking in the microporous layer, so that the ventilation performance of the microporous layer is affected. In order to provide the microporous layer with good air permeability, the air is uniformly delivered to each region of the microporous layer, and fine channels are arranged in the microporous layer. Drainage of the microporous layer relies on capillary action to drive liquid water into the pores of the microporous layer and transport the water to the substrate layer for drainage under the combined action of capillary force and a hydrophobic gradient. When the pores in the microporous layer are too fine, the surface tension of the liquid water may prevent the liquid water from entering the pores of the microporous layer, thereby resulting in poor drainage performance. This results in the inability of existing gas diffusion layers to simultaneously compromise both drainage and gas permeability, thereby affecting the performance of proton exchange membrane fuel cells. Disclosure of Invention The application aims to provide a gas diffusion layer, a preparation method thereof and a proton exchange membrane fuel cell, so as to solve the technical problem that the gas diffusion layer in the proton exchange membrane fuel cell in the prior art cannot simultaneously consider drainage performance and air permeability. In order to achieve the purposes of the application, the technical scheme adopted by the application is as follows: In a first aspect, embodiments of the present application provide a gas diffusion layer. The gas diffusion layer comprises a substrate layer and a microporous layer attached to one side