Multicomponent, multiphase interactions in fuel-cell inks

Abstract

Fuel-cell catalyst layers (CLs) are porous electrodes that are fabricated from CL inks: colloidal dispersions of catalyst particles and ion-conducting polymer (ionomer), dispersed in solvent(s). The complex interactions between the ink components ultimately dictate CL microstructure and electrochemical performance. To control the CL formation process and optimize fuel-cell performance, knowledge of these ink interactions is vital. In this review, we analyze data from ink-focused papers to elucidate how ink parameters (solvent type, ionomer-to-carbon ratio, etc.) impact ink interactions and CL performance. We then discuss these results in the context of the current understanding of two critical ink interactions: ionomer/solvent and ionomer/catalyst particle interactions. • Catalyst layer microstructure/performance controlled by ink interactions/parameters. • Regression analysis performed to analyze most sensitive parameters. • Ionomer-to-carbon ratio and ink solvent determine final catalyst layer properties. • Ionomer/particle and ionomer/solvent interactions are critical.