Understanding Ink Dispersion as an Essential Tool in Large-Scale CCM Manufacturing

At the basic R&D scale (<50 ml), the primary focus is on preserving the properties of the catalyst and ionomer and their interactions within a given solvent system. These inks are applied using single-sheet techniques such as bar coating, doctor blade, and Mayer rod coating—methods that are more forgiving in terms of viscosity, particle size distribution, and ink rigidity. However, at prototype scale (2L) and during second-phase validation, the rheological properties of the ink, ensuring adaptability to roll-to-roll (R2R) manufacturing, become a priority alongside safety considerations.Achieving consistent, scalable, and safe prototype-scale ink dispersions is a complex process requiring careful evaluation of available technologies. This paper explores the influence of different dispersion technologies on ink performance, particularly focusing on how particle size distribution (PSD), viscosity, and ionomer-catalyst interactions impact coating quality and electrochemical performance. We demonstrate that both grinding (BM) and high-pressure dispersion (HPD) techniques achieve desirable PSDs and coating homogeneity. However, differences in viscosity significantly affect catalyst layer morphology and high-current-density performance. Our findings highlight that beyond achieving target PSD, the drying behaviour and ink flow—strongly influenced by viscosity and dispersion method—are critical to optimizing the final electrode structure and performance.