The microstructure of the catalyst layer has a great influence on the performance of the fuel cell. Industrial camera and optical microscope are used to observe the drying process and deposition of catalyst inks, and electrochemical tests are performed by linear sweep voltammetry. The focus is on the drying kinetics of the catalyst ink with different isopropyl alcohol (IPA) contents in the solvent and the effect on the formation of the microstructure. Experiments have found that the deposition height is symmetrical in the diameter direction. A coffee ring is formed at the edge of the deposition, and the slender aggregates are arranged in the shape of petals inside the edge. As the IPA content decreases, the deposition becomes more uneven, the circulatory flow is gradually activated, and a large number of particles run from the edge of the droplet to the center.
Keywords Catalyst ink, Solvent evaporation, Drying kinetics, Catalyst layer, Microstructure, Proton exchange membrane fuel cell