Screen Printing Catalyst Inks With Enhanced Process Stability for PEM Fuel Cell Production

Abstract

Current state-of-the-art coating techniques for PEM fuel cell electrode manufacturing such as slot-die coating use closed ink reservoirs, allowing low boiling point solvents as the dispersion matrix for solid components of the catalyst ink. Applying such low boiling point inks to printing methods that expose catalyst inks to air, like flatbed screen printing, results in an instable and nonscalable production process due to the successive evaporation of these solvents. Within this study, a total of 12 different solvents are examined for process stability and electrochemical performance when applied with flatbed screen printing. Ink characteristics, such as contact angle, rheology, and sedimentation experiments, are quantified to reveal the most suitable set of solvents, enabling the use of open-reservoir printing methods like flatbed screen printing. Additionally, electrochemical in situ characterization of catalyst-coated membranes showed that 1,2-propanediol and 1-heptanol are solvents that combine process stability with high fuel cell performance.