Gas diffusion layer for improving water management capability of fuel cell and preparation method of gas diffusion layer

Abstract

The invention belongs to the technical field of fuel cells, and particularly relates to a gas diffusion layer for improving the water management capability of a fuel cell and a preparation method thereof. Differential gradient structure design is carried out on the microporous layer of the cathode / anode gas diffusion layer, the cathode is designed to be of a double-layer gradient structure, the anode is of a three-layer gradient structure, the purposes of moisturizing under the low-humidity condition and draining under the high-humidity condition in the working state of the fuel cell are achieved, the reaction efficiency in the reaction process of the fuel cell is better improved, and the service life of the fuel cell is prolonged. The water management capability of the fuel cell is greatly improved, so that the output performance of the fuel cell is improved. In addition, the operation process is simple, only slurry preparation, coating, drying and roasting are needed, and rare reagents and complex instruments and equipment are not needed.

Description

technical field [0001] The invention belongs to the technical field of fuel cells, and in particular relates to a gas diffusion layer for improving the water management capability of fuel cells and a preparation method thereof. Background technique [0002] Hydrogen energy is an ideal clean energy. Hydrogen fuel cell vehicles have the advantages of fast filling speed, good low-temperature performance, and long cruising range. It is an important direction for future automobiles to be electrified and low-carbon. Low-carbon transportation has far-reaching significance. Among them, the proton exchange membrane fuel cell (PEMFC) has been widely researched and popularized due to its advantages of high power density and fast start-up speed. During the reaction process of PEMFC, the proton exchange membrane needs to be fully wetted, because the protons generated in the anode catalyst layer are hydrated protons (H 3 o + ) in the form of transmission. In the absence of water, the ...

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Problems solved by technology

Antonacci P et al. (document Balancing mass transport resistance and membrane resistance when tailoring microporous layer thickness for polymer electrolyte membrane fuel cells operating at high current densities. ElectrochimicaActa, 2016,188:888-897) adjusted the thickness of the microporous layer and found that the thickness of the microporous layer was The drainage performance is the best under the condition of high current density at 50 microns, without considering the influence of the pore size of the microporous layer

CN111146467A discloses a preparation method of a microporous layer gas diffusion layer with gradient pore size. Different kinds of carbon powder, absolute alcohol and hydrophobic agent are used to form a slurry, and two layers of microporous layers with different pore sizes are coated on the support layer. , so that the pore size tends to increase from the catalyst layer to the support layer, which is conducive to the discharge of water under high humidity. However, this method cannot achieve the effect of moisturizing under low humidity, and does not consider the difference in the water content of the cathode and anode.

At present, most of the work on gas diffusion layer to improve water management has the following common problems: ① the anode and cathode adopt an indiscriminate gas diffusion layer structure; ② the moisture retention performance under low humidity conditions is not considered

US6821661 discloses a gas diffusion layer with a hydrophilic anode, and carbon fibers with low hydrophobicity are introduced into the carbon paper of the support layer of the anode gas diffusion layer, so that the anode is relatively hydrophilic and the cathode is relatively hydrophobic, so that the effect of moisturizing the anode can be achieved, but There is a microporous layer with a certain thickness (usually dozens or even hundreds of microns) between the supporting layer carbon paper and the catalyst layer, so the moisturizing and drainage effects will be greatly reduced

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