The influence of ultrasonic spray technology parameters on the electrochemical characterization of the catalyst layer directly sprayed onto the diffusion layer in membrane electrode assembly (MEA)

In PEMFC fuel cells, the catalyst layer plays a crucial role, significantly influencing the characteristics of the fuel cell. Various methods for fabricating this catalyst layer, such as brushing, decanting, and spraying, are employed. In this report, the method of fabricating the catalyst layer by directly spraying the catalyst onto the gas diffusion layer with an ultrasonic spraying device is implemented. The impact of some spraying parameters, such as solvent ratio and spraying rate, on the electrochemical activity of the catalyst layer is investigated. The electrochemical properties are evaluated using techniques such as LSV and CV. The uniformity and surface morphology of the catalyst layer are assessed using optical microscopy. The electrical properties of the catalyst layer are assessed through the employment of I-V curve measurements. The results are discussed and indicate that the spraying mode gives a high-quality catalyst layer at a solvent dilution ratio of 60% of the initial catalytic ink solution and a spraying rate of 1.5 ml/min. And this mode is applied to fabricate the catalytic layer for PEMFC fuel cells.