Hydrophilic/hydrophobic composite multilayer membrane electrode and preparation method thereof

Abstract

The invention discloses a hydrophilic / hydrophobic compound multilayer membrane electrode and a preparation method thereof. The membrane electrode comprises an anode catalyst layer, a proton exchange membrane, and a cathode catalyst layer, wherein the cathode catalyst layer comprises a three-layer composite structure with a hydrophilic gradient, the layer which is near the proton membrane is a hydrophilic modification layer, the layer which is near a gas diffusion layer is a hydrophobic modification layer, and the middle part between the two layers is a unmodified layer, so that the hydrophilic gradient is formed in the cathode catalyst layer. The hydrophilic layer has moisture retention effects for ionic polymers in the proton exchange membrane and the catalysis layer in a condition with low relative humidity, so that ionic conduction resistance of the membrane electrode is reduced. The hydrophobic layer reduces a capillary pressure gradient between the catalyst layer and the gas diffusion layer, and diffusion of water from the diffusion layer to the catalyst layer in a condition with high relative humidity is inhibited. The scheme is used for realizing the purpose for optimizing water distribution in catalyst layers.

Description

technical field [0001] The invention relates to the technical field of proton exchange membrane fuel cells, in particular to a hydrophilic / hydrophobic composite multilayer membrane electrode for proton exchange membrane fuel cells and a preparation method thereof. Background technique [0002] As the core component of a fuel cell, the membrane electrode includes an anode catalyst layer, a proton exchange membrane and a cathode catalyst layer. It is the reaction site of the fuel cell and realizes the conversion of chemical energy into electrical energy. The catalytic layer of the membrane electrode is mainly porous structure, the reaction gas enters the catalytic layer through the pores to react, and the generated water is discharged from the pores. Under low humidity conditions, the water content in the catalytic layer is less, the conductivity of the proton membrane decreases, and the performance of the battery decreases; under high humidity conditions, liquid water accumul...

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Problems solved by technology

Increasing the doping amount will lead to a decrease in the porosity of the catalytic layer, which will affect the mass transfer of the battery.

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