Production method of membrane electrode diffusion layer for fuel cell

Abstract

The invention belongs to the field of fuel cell membrane electrodes, and concretely relates to a production method of a membrane electrode diffusion layer for a fuel cell. The production method comprises the following steps: 1, cleaning carbon paper with ethanol, drying the cleaned carbon paper, impregnating the dried carbon paper in a polytetrafluoroethylene emulsion, and sintering the impregnated carbon paper to obtain polytetrafluoroethylene supported carbon paper; 2, coating the carbon paper obtained in step 1 with a carbon powder slurry prepared from acetylene black, water and a binder; 3, sequentially carrying out hot air box drying and cold air box cooling on the carbon paper obtained in step 2; and 4, drying the carbon paper obtained in step 3 in a drying box to obtain the carbon paper which is the membrane electrode diffusion layer. A dispersant used in the invention is water, is cheap, has a good kneading effect with the binder, does not generate irritating smell in the production workshop, and is highly safe; and the produced diffusion layer has the advantages of uniform thickness, flat surface, improvement of the performances of a membrane electrode, large coating area, simplicity in production, and greatly improved production efficiency.

Description

technical field [0001] The invention belongs to the field of fuel cell membrane electrodes, and in particular relates to a preparation method of a fuel cell membrane electrode diffusion layer. Background technique [0002] The fuel cell membrane electrode is mainly composed of proton exchange membrane, catalytic layer and diffusion layer. Among them, the diffusion layer is composed of carbon paper and surface coating. The main function of carbon paper is to support the catalytic layer and collect current. The surface coating mainly improves gas diffusion channels and electron mass transfer channels for internal reactions. When preparing the diffusion layer, first configure carbon Powder slurry, the carbon powder slurry is coated on the carbon paper by spraying method to form a surface coating, the carbon powder slurry includes acetylene black carbon powder, dispersant and binder, and the dispersant is selected from ethanol, isopropyl Alcohol dispersants such as alcohol and ...

AI Technical Summary

Problems solved by technology

Among them, the diffusion layer is composed of carbon paper and surface coating. The main function of carbon paper is to support the catalytic layer and collect current. The surface coating mainly improves gas diffusion channels and electron mass transfer channels for internal reactions. When preparing the diffusion layer, first configure carbon Powder slurry, the carbon powder slurry is coated on the carbon paper by spraying method to form a surface coating, the carbon powder slurry includes acetylene black carbon powder, dispersant and binder, and the dispersant is selected from ethanol, isopropyl Alcohol dispersants such as alcohol and ethylene glycol, these dispersants are irritating, and the production safety is not high. In the prior art, the fuel cell membrane electrode diffusion layer is prepared by spraying, and the prepared diffusion layer has uneven thickness and uneven surface. The flatness makes the utilization rate of the catalyst decrease after the combination of the diffusion layer and the catalytic layer. At the same time, it also makes the contact between the catalytic layer and the proton exchange membrane poor, which affects the performance of the membrane electrode, and the preparation time is long, which limits the wide application of fuel cells.

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