Development of fluorine-free microporous layer composed of thermosetting melamine resin via dry coating process for polymer electrolyte fuel cells

As polymer electrolyte fuel cells (PEFCs) become more widespread, there is growing demand to reduce the environmental impact of their production and to comply with regulations covering perfluoroalkyl and polyfluoroalkyl substances (PFAS). In particular, the conventional polytetrafluoroethylene (PTFE)-based slurry process used to form the microporous layer (MPL) of the gas diffusion layer (GDL) requires high-temperature heat treatment and decomposition of surfactants, leading to significant energy consumption and a high environmental burden. In this study, a dry coating process was applied to the fabrication of GDLs using thermosetting melamine resin as a fluorine-free binder to develop a PFAS-free energy-efficient MPL. By combining hydrophilic carbon black with melamine resin and optimizing the heat treatment conditions, curing was achieved at a lower temperature (approximately 250 °C) than that of conventional PTFE-based MPLs, while significantly improving peel strength. Single cells were fabricated with the developed MPL applied to the anode, and their performance was evaluated. The results demonstrated performance equivalent to or higher than that of PTFE-based MPLs, confirming the practicality of this approach. This process provides a practical pathway toward high-performance, PFAS-free PEFC components with reduced environmental impact. • A PFAS-free microporous layer was fabricated using a dry coating process with melamine resin. • Low-temperature curing (∼250 °C) achieved high peel strength without PTFE or surfactants. • Hydrophilic carbon black improved binder dispersion and mechanical integrity of the MPL. • Single-cell tests showed performance comparable to PTFE-based MPLs when applied to the anode. • The proposed process reduces energy consumption and environmental impact of PEFC manufacturing.